|Year : 2014 | Volume
| Issue : 1 | Page : 8-21
Expediency of dengue illness classification: the Sri Lankan perspective Highly infectious tick-borne viral diseases: Kyasanur forest disease and Crimean-Congo haemorrhagic fever in India
Devendra T Mourya, Pragya D Yadav, Deepak Y Patil
Maximum Containment Laboratory, Microbial Containment Complex, National Institute of Virology, Pune, Maharashtra, India
|Date of Web Publication||24-May-2017|
Devendra T Mourya
Director, National Institute of Virology, 20-A, Ambedkar Road, Pune-411001
Ticks are distributed worldwide and can harbourand transmit a range of pathogenic microorganisms that affect livestock and humans. Most tick-borne diseases are caused by tick-borne viruses. Two major tick-borne virus zoonotic diseases, Kyasanur forest disease (KFD) and Crimean-Congo haemorrhagic fever (CCHF), are notifiable in India and are associated with highmortality rates. KFD virus was first identified in 1957 in Karnataka state; the tick Haemaphysalis spinigera is the main vector. During 2012–2013, cases were reported from previouslyunaffected areas in Karnataka, and newer areas of Kerala and Tamil Nadu states. These reports may be the result of improved active surveillance or may reflect altered virus transmission because of environmental change. CCHF is distributed in Asia, Africa and some part of Europe; Hyalomma spp. ticks are the main vectors. The existence of CCHF in India was first confirmed in 2011 in Gujaratstate. In 2013, a non-nosocomial CCHF outbreak in Amreli district, as well as positive tick, animal and human samples in various areas of Gujarat state, suggested that the virus is widespread in Gujarat state, India. The emergence of KFDand CCHF in various Indian states emphasizes the need for nationwide surveillance among animals and humans. There is a need for improved diagnostic facilities, more containment laboratories, better public awareness, and implementation ofthorough tick control in affected areas during epidemics.
Keywords: Crimean–Congo haemorrhagicfever, India, Kyasanurforestdisease, tick-borne diseases, ticks
|How to cite this article:|
Mourya DT, Yadav PD, Patil DY. Expediency of dengue illness classification: the Sri Lankan perspective Highly infectious tick-borne viral diseases: Kyasanur forest disease and Crimean-Congo haemorrhagic fever in India. WHO South-East Asia J Public Health 2014;3:8-21
|How to cite this URL:|
Mourya DT, Yadav PD, Patil DY. Expediency of dengue illness classification: the Sri Lankan perspective Highly infectious tick-borne viral diseases: Kyasanur forest disease and Crimean-Congo haemorrhagic fever in India. WHO South-East Asia J Public Health [serial online] 2014 [cited 2019 Jul 18];3:8-21. Available from: http://www.who-seajph.org/text.asp?2014/3/1/8/206890
| Introduction|| |
Globally, ticks are the important arthropod vectors for transmission of numerous infectious agents and are responsible for causing human and animal diseases. Various wild and domestic animals are reservoir hosts for tick-borne pathogens of livestock, pets and humans. Ticks are obligatory blood-sucking ectoparasites that infest mammals, birds, reptiles and amphibians. Eighty per cent of the world’s tick fauna are hard ticks and the remaining 20% are soft ticks. However, only 10% of the total hard and soft tick species are known to be involved in disease transmission to domestic animals and humans. Ticks suck host blood during their lengthy attachment period (7–14 days); this may extendJdepending on the association of the tick species and host. Tick-borne diseases are prevalent only in specific risk areas where favourable environmental conditions exist for individual tick species. Worldwide increases in the incidence of tick-borne diseases have been reported., Human tick-borne diseases have been recognized since the discovery of Lyme borreliosis, which is transmitted by Ixodid ticks. Rocky Mountain spotted fever, caused by Rickettsia rickettsia, is transmitted by Dermacentor spp. in the United States of America 0JSA). There are several other rickettsial infections like rickettsioses and Boutonneuse fever (caused by Rickettsia conorii found in Europe), transmitted by Rhipicephalus sanguineus and other tick species. Generally, tick-borne virai diseases manifest three different clinical conditions: encephalitis, haemorrhagic fevers, and acute febrile illness. Among viral infections, European tick-borne encephalitis and the severe Russian spring–summer encephalitis are transmitted by Ixodid spp.,
Hyalomma anatolicum anatolicum and Haemaphysalis spinigera are the two important species of ticks present in India, which are responsible for causing the fatal tick-borneviral diseases of Crimean-Congo hemorrhagic fever (CCHF) and Kyasanur forest disease (KFD), respectively., The tick species are widely distributed in different parts of world, including India (see [Figure 1] and [Table 1]).,
|Figure 1: The distribution of predominant Hyalomma anatolicum anatolicum and Haemaphysalis spinigera tick species of ruminants in India.|
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|Table 1: Association of virus isolation from ticks (Hyalomma and Haemophysalis) and arboviral zoonotic diseases (KFDV and CCHFV) of India|
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The highly infectious nature of KFD and CCHF causes sporadic outbreaks among humans. These viruses have emerged in comparatively new areas, revealing gaps in many areas in understanding these diseases., This paper focuses particularly on the Indian scenario of KFD and CCHF infections, clinical and epidemiological features of the diseases, active surveillance programmes among humans and animals, the role of ticks as vectors, and current policies for management of their control and for raising public awareness.
Highly infectious tick-borne viral diseases in India
1. Kyasanur forest disease
The KFD virus (KFCV) is a member of the genus Flavivirus and family Flaviviridae. It was first recognized in 1957, when an illness occurred concomitantly in monkeys (Semnopithecus entellus and Macaca radiata) and in humans. The virus was initially suspected as a Russian spring-summer (RSS) complex of viruses, since isolates from monkeys and human showed relatedness to this virus.
Mode of transmission of KFD virus
KFDV is transmitted to the wild monkeys Semnopithecus entellus and Macaca radiate, through the bites of infected H. spinigera ticks. After infection, KFDV is transmitted to other ticks feeding on the infected animals. Infection causes severe febrile iliness in some monkeys. When infected monkeys die, the ticks drop fromtheirbody, thereby generating hotspots of infectious ticks that further spread the virus ([Table 1]). The genus Haemaphysalis includes 177 species. The ticks are smaii (unfed adults <4.5 mm long), brownish or reddish, and eyeless, and have very short mouthparts. They are easy to differentiate from other genera by the characteristic lateral projection of a palpal article 2 beyond the margins of the basis capituli. All Haemaphysalis spp. are three-host ticks. H. spinigera is the main vector of KFD, which is endemic in Karnataka state, India. A large number of isolations have been obtained from ticks, and H. spinigera contributed about 95% of these isolations. This is the predominant tick species found in the forest. Among other susceptible species of Haemaphysalis, in addition toH. spinigera, are H. turturis, H. papuana kinneari, H. minuta, H. cuspidata, H. bispinosa,Η. kyasanurensis,Η. wellingtoni andΗ. aculeate. Transmission of KFDV in the laboratory has been demonstrated in a number of Haemaphysalis and Ixodes species.,,,,,,,,,
Humans become infected through the bite of infected unfed nymphs, which appear to be more anthropophilic than mature ticks. Ticks have also been found to transmit this virus transstadially, thus also acting as a reservoir for the virus. In Karnataka state, the activity of nymphs is very high during November to May, correlating with a higher transmission rate of KFD at this time of year. Adult fed female ticks lay eggs, which hatch to larvae under the leaves. They further infest small mammals and monkeys, as well as accidentally infesting humans, and feed on their hosts. Subsequently, they mature to nymphs, and the cycle is repeated. Nymphs and adults also transmit the disease to rodents and rabbits by bite, and this rodent-tick cycle continues for more than one life-cycle.
The finding that immature stages of H. spinigera infest a variety of hosts, such as birds, monkeys, rodents, cattle and buffaloes, and that these hosts are highly susceptible to the virus, suggests that this species of tick might indeed be an important vector for the disease.,
Although human-to-human transmission is not known, more than 100 human cases have been reported in the past while workingonthevirus. During arecent outbreakof KFD (2013) in Bandipur Tiger Reserve forest, it was found that animal handlers became infected while handling sick monkeys. Owing to the large number of KFD laboratory-associated infections at the National Institute of Virology (NIV), Pune, work on this virus was stopped for 30 years, however NIV started working on the virus again after establishment of a Biosafety Level-3 (BSL-3) laboratory.
Geographical distribution of KFD virus in India and its detection in newer areas
After the discovery of KFD, it was mainly confined to three taluks (Sagar, Shikaripur and Sorab) of the Shimoga district of Karnataka, until 1972’ Thereafter, foci were reportedfromfour additional areas, namely Chikmagalur, Dakshina Kannada, Udipi and Uttar Kanada districts of Karnataka state. For a long time, KFD was thought to be endemic in the Shimoga district However, serological evidence obtained in the past during different studies, suggests that KFD virus or related viruses are present in other areas of India, which include parts of the the Saurashtra region in Gujarat state, forested regions west of Kolkata, West Bengal state, and the Andaman Islands.,
Since 1957, the estimated incidence of KFD in India has been 400–500 cases per year. The epidemic period begins in November or December and peaks from January to Aprii, then declines by May and June. Between 2003 and March 2012, there were 3263 reported human cases and, of these, 823 were laboratory confirmed. Large numbers ofhuman infections were reported in 2003–2004, but a significant decline occurred in 2007 and again in 2010–2011., The frequency of cases can be correlated with the number of confirmed KFD-infected non-human primates. As far as spread in new areas is concerned, an outbreak of KFD was reported for the first time in December 2012 in Chamraj anagar district of Karnataka. In 2013, KFDV was detected in autopsy of dead monkeys in Nilgiris District, Tamil Nadu and in a human case from Wayanad district, Kerala [Figure 2]). Already in 2014, an outbreak of KFD has been confirmed by screening human samples, monkey necropsy samples and tick pools from the Kannangi and Konandur areas in Thirthahalli taluk. Data indicate that, this year, the main focus activity was in Shimoga District (NIV unpublished data).
|Figure 2: Pictorial presentation of KFD activity in Karnataka, Kerala and Tamil Nadu and CCHF positivity in Gujarat State.|
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In earlier years, the geographic area affected was small and the number of cases was relatively low, while, with the increase in the number of foci, the incidence has increased. These facts suggest that constant changes in the ecobiology, including deforestation and new land-use practices for farming and timber harvesting, might have led to the spread of this disease to newer localities.
Phylogenetic relation and ancestry of KFD virus in India
The positive-sense RNA genome of the KFDV is about 11 kb in length and encodes a single polyprotein that is cleaved post-translationally into three structural (C, M and E) and seven non-structural (NS1, NS2a, NS2b, NS3, NS4a, NS4b and NS5) proteins. Evoiutionary studies undertaken earlier for KFDV, based on Bayesian molecular clock analysis (partial E and NS5 gene sequences of ~50 KFD viruses), revealed a rate of evolution of ~6.4 × 10−4 substitutions/site/year withthe divergence of KFDV estimated to have occurred 62 years ago. However, a recent study based on analysis of full-length sequences (KFDV n = 3 and Alkhurma; haemorrhagic fever virus n = 18 – a variant of KFDV in Saudi Arabia) revealed a slower rate of evolution (9.2 × 10−5 substitutions/site/year with substitutions/site/year) and a much older ancestry of KFDV., Though the number of KFDV isolates that were available at the time of the study was limited, it appears that the analysis of full-length genomes might have provided a more accurate estimate of an older ancestry and also suggests that the evolution of tick-borne viruses was more gradual than that of rapidly evolving mosquito-borne viruses. Phylogeography studies for KFDV are also important to geneticaUy characterize the recently circulating KFDVs and understand the dispersal pattern of the virus within Karnataka and to newer geographical areas.
Clinical signs and symptoms
In humans, the incubation period of KFD is estimated to be about 2 to 7 days after tick bites or exposure. The onset is sudden, with chills followed by severe frontal headache. Fever soon follows headache and iapidly rises to 104°F. This raised temperature is continuous and lasts for 5–12 days, or even longer. There is severe myalgia, which is reminiscent of dengue. Body pains are ofhigh intensity at the nape of the neck, lumbar region and calf muscles. Diarrhoea and vomiting occur by the third or fourth day of illness. Bleeding from the nose, gums and intestines begins as early as the third day, but the majority of cases run afull course without any haemorrhagic symptoms. Gastrointestinal bleeding is evidenced by haematemesis or fresh blood in the stoois. Some patients have persistent cough, with blood-tinged sputum and occasionally substantial haemoptysis. Physicaľexaminations during the first few days of illness reveal an acutely ill, febrile patient with a severe degree of prostration. There is usually conjunctival suffusion and photophobia. The cervical lymph nodes are usually palpable, as are the axillary epitrochiear lymph nodes in some cases. A very constant feature is the appearance of papulovesicukr lesions on the soft palate, but no skin eruption has been noted. The convalescent phase of the disease is prolonged. Often, the disease runs abiphasic course; the second phase occurs after a febrile period of 1 to 2 weeks. The fever iasts from 2 to 12 days ([Table 2]). It is initiatedby headache and by this time abnormalities of the central nervous system are generally present. Neck stiffness, mental disturbance, coarse üemors, giddiness, and abnormality of reflexes are noted., Clinically, KFD resembles Omsk hemorrhagic fever (OHF), which occurs in the Omsk Oblast in Siberia The other tick-borne viral disease antigenically related to KFD and OHF is tick-borne encephalitis.
|Table 2: Clinical phases of Kyasanur forest disease virus and Crimean-Congo hemorrhagic fever virus infection and tests used for diagnosis.|
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Owing to the variability in clinical illness associated with KFD infection, and the lack of data available on clinical diagnosis of KFD, it is essential to emphasize the importance of laboratory confirmation of the disease. The following case definitions are proposed:
Case definition:a patient of any age presenting with acute fever, headache and myalgia, and a histoiy of exposure to ticks and/or a visit to a forest area and/or living in, a KFD-endemic area, particularly forest in Karnataka.
Suspected case:a patient, within a radius of 5 km surrounding the villages reporting recent monkey deaths or laboratory-confirmed KFD cases, with sudden onset of high fever and one ofheadache or myalgia.
Probable case:a clinically compatible illness that does not meet the SOPs for a confirmed definition, but with one of the following:
- epidemiological link to a documented exposure to a KFD-affected area (one or more of the following exposures within the 3 weeks before onset of symptoms),
- positive result on testing of clinical serum specimens using the immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA).
Confirmed case:a confirmed case of KFD is defined as a case that fulfils the criteria for a probable KFD case and, in addition, it should cover any of the following:
- exposure to secretions from a confirmed acute or convalescent case of viral haemorrhagic fever (VHF) within 10 days of that person’s onset of symptoms;
- isolation of KFDV in cell culture or in a mouse model, from blood or tissues;
- detection of KFDV-specific genetic sequence by reverse transcription-polymerase chain reaction (RT-PCR) or real-time RT-PCR from blood or tissues.
In the KFD-endemic area of Karnataka state, India, the differential diagnosis should include consideration of influenza, typhoid and rickettsial group of fevers, for example, Q fever and mite-borne typhus in mild cases, and malaria and leptospirosis in moderate to severe cases.
Hospital laboratory testing: The following tests should be performed on blood samples from enrolled patients, according to standard hospital procedures:
- complete blood count (CBC): total leukocytic count (TLC)/ differential leukocytic count (DLC), haemoglobin level, and platelet counts,
- liver function tests (aspartate aminotransferase (AST)/ alanine aminotransferase (ALT), serum bilirubin, aikaIine phosphatase);
- serum electrolytes, blood urea, serum creatinine;
- smear for malaria parasite or malaria rapid diagnostic test.
Standardized, detailed SOPs shoukl be provided to each of the hospital wards and laboratories, to ensure proper collection of each of the specimens. Personal protective equipment should be used by the collecting technician or care provider in all cases. Blood samples shouldbe collected from tiĪe hand or antecubital fossa by the treating physician, by venipuncture with an aseptic techniquee. For surveillance purposes, this should be done on two separate occasions – imtiaily at the time of enrolment/ admission, and then 10 days after initial specimen collection or at the time of discharge from the hospital (if less than 10 days). In cases of fatality, the second specimen should be collected at the time of death.Diagnostic laboratory testing: For a long period, there were no studies done on KFD; hence, hemaggiutination inhibition (HI), hemagglutination (HA), complement fixation and in vivo inoculation of patients’ sera into suckling mice were the tests of choice for diagnosis. During KFDV infection, the level of viraemia reaches up to 3X10” within 3–6 days and remains high for as long as 10–14 days of infection. Therefore, the period of higher viraemia coincides with the time at which patients usuaily report to hospital and collection of a blood sample for laboratory diagnosis. Therefore, an early and effective diagnosis strategy is essential.
After establishment of the first BSL-3 laboratory of India at NIV, Pune, real-time RT-PCR, RT-PCR and detection of IgM and IgG antibodies by ELISA were developed and standardized. KFDV can be isolated from the blood of patients (in acute phase 2–5 days), positive tick pools, or the blood orviscera ofmonkeys by inoculation into infant mice, or in vitro using Vero E6, BHK-21 or chick embryo cells. In all these systems, infant mice are found to be the most susceptible for virus isolation. KFD anti-IgM antibodies can be detected using ELISA during the acute phase (4 days onward) (see [Table 2]). The front-line test for KFD is real-time RT-PCR and RT-PCR from blood/serum of humans, blood and viscera of infected monkeys, or tissues of ticks. According to what is known, real-time RT-PCR can detect the virus m human samples after onset of febrile illness up to the 10th day (NIV data). Clear information about the KFD viraemia phase, the interrelationship of IgM and IgG antibodies, and the duration of persistence of these antibodies in naturally infected patients remains to be understood ([Table 2]). Suspected samples should be shipped according to internationaf regulations for the shipment of infectious agents, following triple container criteria’
No specific treatmentforKFD is available; however, supportive therapy is important. This includes maintenance of hydration and the usual precautions for patients with bleeding disorders.
Guidelines for management of KFD cases
In recent years, state public health agencies in the affected districts have made efforts to ensure adequate staff and infrastructure at primary health-care (PHC) and secondary-level health facilities, to provide health care to critically 111 patients, undertake training of staff, and minimize the frequency of transfer of trained staff. The role and responsibilities of health-care providers at different levels of health facilities are explained, and medical officers are trained to identify the suspected KFD cases. Government has made provision for well-equipped ambulances for transfer of criticaUy ill patients from community to PHC or from PHC to secondary health-care facilities. For better organization of the health-care-delivery system, mapping of primary, secondary and tertiary care health facilities in high-risk areas has been made available. KFD cases are recorded annually, thereby monitoring the annual disease burden at all the health facilities, for better understanding and preparedness for KFD disease. Continuous information, education and communication activities with regard to early recognition of suspected KFD cases are carried out among newiy recruited medical officers and other relevant populations, State government educates the villagers and tourists who visit the forest in Karnataka state about using repellent and gum boots and having prior vaccination. Whenever monkey deaths are reported, rapid action is taken to transmit information to health officers and veterinary staff for necropsy of monkeys, collection of specimens for diagnosis of monkey samples, and proper disposal of dead monkeys. If a monkey is found positive for KFDV, vaccination of human subj ects should be carried out in those areas. Education has been provided in local languages every year. As soon as suspected cases are notified they are referred to NIV, Pune for investigation and confirmation.
Improper storage of vaccine and lack of maintenance of the cold chain result in ineffectiveness of the vaccine and could be another reason for the emergence of KFD despite routine vaccination. The trend of increasing numbers of patients infected with KFD in Karnataka state warrants development of a new vaccine – either recombinant, or a virus-like-particle-based vaccine – which will help in controlling the disease.
The formalin-inactivated KFDV vaccine produced in chick embryo fibroblasts is currently in use in the endemic areas in Karnataka state of India. The vaccine was found to be immunogenic, potent, stable and safe. The production of inactivated vaccines carries the inherent risk of utilizing large quantities of potentially highly pathogenic viruses aiid the possibility of incomplete inactivation of viruses. In addition, vaccines based on inactivated viruses as antigens have shown a certain level of adverse reactions, especially in children, and this has to be carefully balanced with their efficacy and durability.
Infected nymphs and larvae are shed in the forest, mainly by the monkeys, rats, shrews, porcupines, squirrels, and probably a few birds that form enzootic foci. Destruction of infected ticks would necessitate control of ticks throughout the entire forested area, but is not technically and economically feasible. This is the main reason why, once focus of this disease becomes established in any biotope, it cannot be eliminated easily. As association of human infections in the vicinity of dead monkeys has been shown, and the use of spray insecticides has been recommended in a 50-m radius around a dead monkey. However, although recommendations have been made for spraying of insecticides around the place of monkey death, it is technically difficult in certain inaccessible areas to transport the large volumes of water needed for the spray. Economic and logistical problems associated with regular insecticide spray in a large area makes implementation of a control programme difficult. Under these circumstances, the prevention of tick bites by the use of repellents should be considered.
2. Crimean-Congo haemorrhagic fever
The Crimean-Congo haemorrhagic fever virus (CCHFV) is also considered as an importantzoonotic virus, owing to its wide distribution and ability to cause disease in humans, where it causes a high mortality rate. Secondly, it has the potential to cause nosocomial cases/outbreaks. CCHF was recognized for the first time in 1944, in the West Crimean region of the former Soviet Union, during a large outbreak, and the virus was subsequently isolated in 1956 from a human case.,,, It is a member of the genus Nairovirus of the family Bunyaviridae. The average case-fatality rate is 30–50%; this varies between 5% and 80% invarious outbreaks, as reported earlier.
Mode of transmission of CCHF virus
Humans become infected through tick bites, by contact with a CCHF-infected patient during the acute phase of infection, or by contact with secretions, blood or tissues from viraemic livestock. Risk groups include individuals who are exposed to ticks (mainly farmers, shepherds and veterinarians), and persons who come in close contact with CCHF patients. Thus, in hospital settings, family or nosocomial outbreaks are observed. Observationof CCHF transmission in India during the year 2011 showed it was mainly nosocomial, and started with an index case history of tick bites and close contact with animals. During June 2012, another episode of nosocomial infections recorded from Ahmadabad city resuhed in two fatalaties. The history of exposure revealed that the treating physician had an accidental contact with the patient (the index case, resident of Bawla Taluka, Ahmadabad), who had similar symptoms of haemorrhagic fever and had died a week earlier. During the CCHF outbreak of 2013 in Karyana village, Amreli district, the main reason for transmission of virus was infected Hyalomma ticks infested on domestic animals. Once a human was infected, the disease was transferred to other close family relatives who either accompanied the infected individual to hospital, lived in the same house, attended the funeral of a person who had died due to CCHF, or came in contact with infected body fluids.
CCHFV circulates in nature in the enzootic “tick-vertebrate-tick” cycle. Ticks of the Hyalomma genus have been reported to be associated with the incidence of the disease and found to play akey role intransmissionof CCHFVto mammals., The CCHF cases coincide with the life-cycle of Hyalomma ticks, and infection mainly occurs during the period when immature ticks are active. H1gh tick activity is associated with warm winters and hot summers. The predominance of tick species as vectors of CCHFV differs geographically and includes H. anatolicum subspecies (H. anatolicum anatolicum), which are distributed throughout Eurasia, while in the northern hah of Africa H. marginatum subspecies (H. marginatum marginatum, H. marginatum rufipes, H. marginatum turanicum and H. marginatum isaaci) predominate. Hyalomma species of ticks are medium to large sized, with long hypostomes and eyes located in sockets. They are mainly found in semi-arid zones, and infest domestic and wild mammals as well as birds. Of the 25 knownHyalomma spp., 15 are important vectors of infectious agents ofveterinary and public health importance. Among these, Hyalomma anatolicum anatolicum is important, and this species has wide distribution in India. Nymphs and unfed adults remain hidden in the dry and winter season in crevices in stone walls, stables and weedy or fallow fields. The life-cycle involves three hosts. This is medically important, since, during the developmental cycle, ticks infest a variety of hosts – smaller to larger mammals, birds or reptiles. They effectively withstand diverse habitats ranging from warm, arid and semi-arid, harsh lowland, and long dty seasons. H. anatolicum anatolicum is known to transmitvirus to humans.
CCHFV has a wide host range and can cause a transient viraemia in many wild, domesticated and laboratory mammals; antibodies against CCHFV have been detected in the sera of variety of ammals.,,, Viraemia does not develop in birds; however, migratory species could carry infected ticks and play a role in disseminating the virus over long distances.
Geographical distribution of CCHF virus in India
CCHF is transmitted to humans and animals by the bite of Ixodid ticks, mainly those of the Hyalomma genus. Thus, the geographic distribution of CCHF is closely related to the global distribution of Hyalomma spp. ticks. CCHFV has been reported in over 30 countries covering Africa, South-Eastern Europe, the Middle East and Western Asia.,
India has always been considered at high risk for CCHF, owing to its borders with affected countries such as China and Pakistan. Because of the long association of India with these adjoining countries and the possible trade of animals across the border, the risk of CCHFV being passed to the Indian subcontinent was recognized. The viruswas first isolated from ticks in Pakistan in the 1960s and the first reported human case occurred inRawalpindi in 1976., Since then, many sporadic outbreaks have occurred in Pakistan every year, resulting in high case fatality., In March 1998, an outbreak with 19 cases and 12 deaths (case-fatality rate 63.2%) was reported from Takhar Province in the northern part of Afghanistan. Since this episode, Afghanistan has seen many outbreaks of CCHF in subsequent years. In Iran, CCHF was first isolated in 1978 and the disease re-emerged in 1999, with high case fatality., In China, CCHF wasfirst isolated in 1965 from a human case and later, in 1984, from H. asiaticum ticks from the same region of Xinjiang province in north-western China, which is considered to be the most CCHF-affected area in the country.,
Until 2011, the existence of CCHF was not known in India, apart from some serological evidence recorded in the past. Serological evidence of the presence of CCHF in India was reported by screening for HI antibodies in animal sera from Jammu and Kashmi, the western border districts, southern regions and Maharashtra state., Shanmugam et al. had reported the presence, in 1973, of CCHFV-specific antibody in nine human samples from Kerala and Pondicherry and in goats from South India. All these studies were based on serological findings only; no virus isolation couldbe achieved and hence no clear evidence of this virus could be obtained. DuringDecember2010,justpriorto the CCHF outbreak, blood samples were collected by NIV, Pune, to examine livestock from abattoirs in the northern adjoining state of Rajasthanand some more distant areas of Maharashtra and West Bengal states, for the presence of CCHFV-specific IgG antibodies. Serum samples ofbuffalo, goat and sheep from Sirohi district, in southern Rajasthan, were found to be positive for IgG antibodies against CCHFV.
The presence of CCHF disease was confirmed for the first time in India during a nosocomial outbreak, in Ahmadabad district, Gujarat state. Samples from three suspected cases. 83 contacts, Hyalomma ticks and livestock were screened for CCHFV by real-time RT-PCR; of these, samples from two medical professionals and the husband of an index case were positive for CCHFV. About 17.0% ofdomestic animals from Kolat, Ahmadabad were positive for IgG antibodies, while only two cattle and a goat showed positivhy by real-time RT-PCR. Surprisingly, in the adjoining village of Jivanpara, 43.0% of domesticanimals (buffalo, cattle, sheep and goats) showed IgG antibodies but only one of the buffalo was positive for CCHFV. The#. anatolicum anatolicum ticks were positive by PCR and virus isolation. Retrospective screening of suspected human samples revealed that the virus was present in Gujarat state, during the year 2010, earlier than this outbreak (see [Figure 2]). After its confirmation in India, sporadic cases of CCHF were reported in 2011–2012. During the period of 23 June to 25 July 2013, a cluster of suspected VHF cases were reported in Kairyana village, Amreli district and, simultaneously, sporadic cases were recorded from Surendra Nagar, Patan district and Kutch district, Gujarat state. Owing to high alertness over 2 months, a total of 198 human samples were processed by real-time RT- PCR and 19 samples were found to be positive for CCHFV. Human suspected cases from Amreli, Kutch, Patan. Rajkot and Surendranagar were found to be positive for CCHF viral RNA. IgG antibody positivity was recorded in animals from Karyana, Nilwada and Khambhala village from Amreli distrct and Kundal village, Ahmadabad district. Surveillance of anti-CCHF IgG in domestic animals showed a number of animals from 15 districts that were positive (see [Figure 3]) CNIV, unpublished data). This emphasizes the necessity of continuous monitoring and screening of syndrome-based cases for CCHF.
|Figure 3: Pictorial presentation of different outbreaks and spread of CCHF in Gujarat State.|
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Ancestry of CCHF virus in India
Sequence-based moleadar characterization of the Indian CCHFV has shown that the virus possesses the functional motifs known to occur in the S, M andL gene segment products, as in other CCHF viruses. The complete genome was found to be 19.2 kb in length. The CCHFV strains cluster into 6–7 distinct groups; West-Africa in group I, Central Africa in group II, South-Africa and West Africa in group III, Middle-East and Asia in group IV, Europe in group V and Greece in group VI. Group IV may split into two distinct groups, Asia 1 and Asia 2.
The s segment of the six Indian CCHFVs showed 99.8% nucleotideidentity. Notably, both tick isolates shared 100% nucleotide identity with one of the Indian human isolates of 2011. Phylogenetic analysis based on the s segment demonstrated that the Indian CCHFV isolates formed a distinct cluster in the Asian–Middle East group IV of CCHF viruses. The s segment was closest to a Tajikistan strain TADJfliU8966 of 1990 (98.5% nucleotide identity) and was of South-Asia 2 type, while the M segment was of type M2. Both M and L segments were closest to an Afghanistan strain Afg09–2990 of 2009 (93% and 98% nucleotide identity) respectively. Complete genome analysis of Indian CCHFV isolates not oniy revealed high genetic diversity but also showed recombination and reassortment, which resulted in more complicated evolutionary routes of the virus than mutation-based selective forces., The molecular clock of Indian isolates has revealed the ancestry of these viruses is not very recent and dates back to about 33 years, on the basis of the s segment, whereas it is about 15 years based on the M segment.
Clinical signs and symptoms
The initial nonspecific symptoms of CCHF can mimic other common infections that occur in India, which may lead to misdiagnosis. The delay of proper treatment and precautionary measures may result in outbreaks, including nosocomial outbreaks of this high-risk group of viruses.,, In India, this disease needs to be differentiated from other infections such as dengue, leptospirosis, rickettsiosis, brucellosis, Q fever and other haemorrhagic fevers. Patient history is very informative, especially when tick bite or travel to currently known endemic areas in Gujarat is evident.
The clinical signs and symptoms are observed between 1 and 3 days (maximum 9 days) after a tick bite; however, when infection is contracted from direct contact with viraemic livestock or CCHF patients, these signs and symptoms may be seen from 5 to 6 days later (maximum 13 days). They include abrupt high fever, severe headache, malaise, nausea, vomiting, diarrhoeaand sore throat. Typically, the disease follows a four-phase course: incubation, pre-haemorrhagic and haemorrhagic phases, and convalescence., Laboratory investigations during the first 5 days of the CCHF disease mostly show leukopenia, thrombocytopenia, elevated liver enzymes and prolonged blood coagulation times. In most cases, platelets 20 × 10−9 /L. or less, AST 700U/L, or more, ALT 900U/L, or more, partial thromboplastin time 60 s or more, and fibrinogen 110 mg/dL or less are suggestive of a fatal outcome., H1gh viral load is also associated with a fatal outcome. In severe cases, approximately 5 to 7 days after the onset of the disease, haemorrhagic manifestations are observed – mainly petechiae, epistaxis, haematomas and vaginal bleeding. Death usually occurs between 5 and 7 day of illness, while survivors show progressive improvement (see [Table 2]). The disease is milder in children and in secondary or tertiary cases., Haemophagocytosis is also one of the consistent features in many cases; however, increased seramferritin levels causedby haemophagocytosis is also one of the consistent features related to the severity of disease. The average period of incubation is around a week. The first phase includes a few days of fever, tiredness, headache and muscle pain, followed by a long asymptomatic period. After that phase, the first signs that the central nervous system has been compromised startappearing, including meningitis, encephalitis and myelitis, which can lead to neurological sequelae and, in a few cases, even death. Information onthe time of appearance of symptom of VHF has varied, ranging between 1 and 21 days after exposure to the virus. Symptoms also depend on the viral species involved and may include fever, tiredness, dizziness, muscle pain, weakness and exhaustion. In more serious cases, there is bleeding under the skin or in internal organs, or bleeding out of the mouth eyes, ears and vagina. Patients with serious illness can show signs of shock or coma, involving neurological symptoms like delirium and convulsions.,
After a tick bite, the incubation period is of short duration (3–7 days). The pre-haemorrhagic period is characterized by sudden onset of fever, headache, myalgia, dizziness and further symptoms of diarrhoea, nausea and vomiting. Hyperaemia of the face, neck and chest; congested sclera; and conjunctivitis are also noted. The haemorrhagic period is shoit, rapidly progresses and typically begins at the third to fifth day of the illness. The haemorrhagic signs vary from petechiae to the appearance of large haematomas on the mucous membranes and skin. Bleeding, commonly from the nose, gastrointestinal system, urinary tract, respiratory tract and other sites including the vagina; gingival bleeding; cerebral haemorrhage; and bleeding from unexpected sites has been reported. The convalescence period begins 10–20 days after the onset of disease. It is characterized by labile pulse, tachycardia, temporary complete loss of hair, polyneuritis, difficulty in breathing, poor vision, loss of hearing and loss of memory.,
Case definition:Defining a case is an important aspect of a surveillance system. The case definition of the disease will be more accurate when it is combined with laboratory confirmation with clinical manifestations.,
The following are the case definitions for CCHF infection:
Suspected case:a patient with abrupt onset of high fever >38’5°C and one of the following symptoms: severe headache, myalgia, nausea, vomiting, and/or diarrhoea and a history of tick bite within 14 days priorto the onset of symptoms; or history of contact with tissues, blood, or other biological fluids from a possibly infected animal (e.g. abattoirworkers,livestock owners, veterinarians) within 14 days prior the onset of symptoms; or health-care workers in health-care facilities, with a history of exposure to a suspected, probable, or laboratory-confirmed CCHF case, within 14 days prior to the onset of symptoms.
Probable case:a probable CCHF case is defined as a suspected CCHF case fulfilling the following additional criteria: thrombocytopenia <50 000 cells/mL and two of the following haemorrhagic manifestations: haematoma at an injection site, petechiae, purpuric rash, rhinorrhagia, haematemesis, haemoptysis, gastrointestinal haemorrhage, gingival haemonhage, or any other haemorrhagic manifestation in the absence of any known precipitating factor for haemorrhagic manifestation.
Confirmed case:a confirmed CCHF case is defined as a case that fulfils the criteria for probable CCHF and, in addition, is laboratory confirmed with one of the following assays: detection by ELISA or immunofluorescence assay of specific IgM antibodies against CCHFV, or a 4-fold increase in specific IgG antibodies against CCHFV in two specimens collected in the acute and convalescence phases, or detection by RT-PCR of CCHF viral RNA in a clinical specimen, confirmed by sequencing of the PCR product or CCHFV isolation.,
Haemorrhagic fevers are contracted through contact with the blood of infected animals, and the bite of infected ticks (CCHF and KFD) and mosquitoes (dengue fever). Some of these fevers can be transmitted from person to person. Laboratory diagnosis of the disease is established by molecular methods, whiie IgM and IgG antibodies become detectable by indirect immunofluorescence assay or ELISA after the fifth day (see [Table 2]).,, However, there are reports that in severe cases no antibody response is observed. Real-time RT-PCR for rapid diagnosis of CCHFV infections is the test of choice in the acute phase, and for ticks., The isolation of CCHFV requires a high-containment B SL-4 laboratory, while viral RNA detection combined with serology for laboratory diagnosis in BSL-3- or BSL-2-compliant laboratories can be canied out following good microbiological practices with standard protocol. The Gujarat Government has planned to upgrade laboratories to provide CCHF diagnosis, with proper biosafety precautions and handling of these samples, after training and acquisition of all the required biosafety equipment.
So far, there is no specific treatment for CCHF. A vaccine based on formalin-inactivated suckling mouse brain, which is not yet approved by the Food and Drug Administration of the USA (FDA), has been used in Bulgaria and the former Soviet Union. Since no specific treatment is available, supportive treatment includes careful fluid and electrolyte balance, monitoring and replacement with platelets, fresh frozen plasma and erythrocyte preparations. The effect of ribavirin is still controversiar;,,,, the drug has not been approved for the treatment of CCHF by the FDA, but is, at present, the only antiviral agent with promising effect, if administered before the fifth day of the disease. It wasobserved that CCHF cases in India supported the use of ribavirin. Ribavirin is contraindicated in patients with chronic anaemia and haemoglobin levels below 8 g/dL, and in patients with severe renal impairment (creatinine clearance <30 mL/min). The drug may accumulate in patients with impaired renal function. If ribavirin is administered, patients should be carefully monitored during therapy for signs and symptoms of toxicity, such as anaemiaľPatients with hypotension or haemodynamic instability should be managed following standard guidelines forthe treaiment of shock, which include resuscitation, fluid supplements (crystalloids/colloids) and ionotropic support. In suspected secondary bacteriai infection, patients should be treated according to standard guidelines/practice for community-acqmred/nosocomial infections. CCHF-venin, an immunoglobulin preparation particularly from the geographical areaswhere this disease is endemic, may be useful by the intravenous route for treatment of patients with severe CCHF.,,,,
Guidelines for management of CCHF cases
In the hospital setting
The following precautions are recommended:
- isolate the patient in a room that is separate from other patients in the hospital;
- medical staff handling the patient should wear gloves and a gown, to avoid direct contact with the patient;
- after handling the patient, medical staff should thoroughly wash their hands, as well as any other parts of their body that came into contact with tiie patient, using soap and water;
- clinical procedures that are likely to cause spraying of bodily fluids should be avoided, or only performed by medical staff wearing a face shield, or a mask and eye goggles;
- bleach can be used for disinfection. A 1:100 dilution of bleach shouldbe usedto clean surfaces, medical equipment, and bedding and clothes. A 1:10 dilution ofbleach should be used to clean up bodily fluids. Alternatively, 5% Lysol may be used.
In the family/community setting
- Family members and friends who had direct contact with the patient should be monitored for 14 days, for onset of a febrile illness.
Dead body disposal
- Rubber gloves or double surgical gloves should be used for handling the dead body. The persons handling the dead body in hospitals should aiso wear a mask and use personal protective equipment.
- The dead body should be sprayed with 1:10 liquid bleach. It should then be wrapped with a winding sheet, which is then sprayed with bleach solution.
- The wrapped and bleached body should be placed in a plastic bag, which is then sealed with adhesive tape before transport.
- The ambulance/transport vehicle should also be disinfected after use.
The main means of CCHF outbreak control, namely breaking the transmission chains by avoiding/minimizing exposure to the virus-infected material, is recommended for prevention. Barrier nursing techniques are essential while treating confirmed and suspected cases of CCHF. Close contacts of the infected patient should be followed up with daily temperature recording and monitoring of symptoms for at least 15 days aftertheputative exposure. Health-care workers shouldtake all the necessary precautionary measures to prevent occupational exposure.
After confirmation of the CCHF outbreak in Gujarat state, a highly efficient network ofhospital reporting of admissions of suspected cases, and help in monitoring the contacts and family members was activated’ Animal diseases health officials and national vector-borne diseases (NVBCD) officials are on alert for sampling of ticks and domestic animal samples from the area of any suspected case in Gujarat state. With the diagnostic support of NIV, Pune in the last 3 years, every suspected case has been referred to NIV for a quick diagnosis, to avoid the spread of infection.,,, An awareness programme is conducted in different government and private hospitals, for reporting and sending samples to NIV, Pune for confirmation. The strategic actions taken by the state government included active human, animal and entomological surveillance. Whenever any deceased CCHF-positive patient is reported, immediate surveillance is conducted for members of the community, for unusual fever symptoms, as well as IgG antibody screening of domestic animals and viral RNA detection in infested ticks, Isolation and treatment of cases following universal precautions is carried out, with contact tracing andmonitoring of contacts, spraying cattle in the affected area with anti-tick agents, spraying human dwelling with residual sprays, and communicating the risk to the public. Owing to proper precautions and quick preventive measures, avoidance of nosocomial infection in humans is optimized.,,
The individuals in outbreak areas who are vulnerable to tick bites, or exposed to infected animals or animal tissues, or health-care and laboratory workers are considered to be at risk of contracting CCHF. Thus, control measures should be mainly focused on tick control in outbreak areas and on personal protective measures for persons caring for CCHF patients.,,,,
Prevention and control with regard to disease-affected animals:
- segregate the animal from other livestock;
- undertake tick control in infected animals, in consultation with the animal husbandry department;
- cattle sheds should be properly disinfected;
- if milking an animal, the milk should not be used for human consumption;
- if animals are slaughtered, proper disposal of carcasses should be performed;
- the left-over feed should be sprayed with 3% bleach and should be disposed of, to ensure that other animals do not feed on it;
- these procedures should be followed for at least 2 weeks and blood samples should be drawn and confirmed to be free of viraemia
Tick bites are best prevented by people avoiding tick-infested areas orby wearing long trousers that are tucked into boots. Tick bites can be prevented by application of a topical repellent to exposed skin and treatment of clothing with insecticide, which gives nearly 100% protection. Dipping is the primary method of tick control for livestock and has been found to be highly effective for controlling several tick-borne diseases. Spraying is another method used to apply the chemical acaricides that kill ticks.,, However, resistance of ticks to acaricides poses an increasing risk to livestock.
| Discussion|| |
According to a recent study from the Zoological Society of London, United Kingdom, along with researchers from Georgia and New York, USA, India is considered a “hot spot” for emerging infectious disease, on a global map. In recent years, vector-borne diseases have emerged as a serious public health problem in countries of the South-East Asia, including India. Many emerging zoonoses have spread globally at the human-animal interface. Risk factors for emergence reside in multiple sectors. India has extremes of climatological and geographical conditions: temperatures that vary from extremely low to high, temperate regions and desert, thick evergreen forest, and areas of high ramfall. Increased population” urbanization, internationaľ travel, change in agriculturai practices, environmental factors, change in lifestyle, deforestation, close contact of animals, and a porous international border make this country a high-risk area for outbreaks of emerging and new diseases.
Vector-borne zoonoses now occur in epidemic form on an almost annual basis, causing considerable morbidity and mortality. All these have impact not only on public health but also on the livelihood and economy of affected countries. A network of laboratories, trained laboratory staff, more high-containment diagnostic laboratories, surveillance programmes, modern equipment and trained medical professionals are required in order that the country is prepared to deal with this kind of emergency situation. KFD was originally assumed to be restricted only to Karnataka state, but there is now evidence of its spread; similarly, CCHF is not restricted to one district but human positivity has now been recorded in seven districts. The recent sero-survey study by NIV, Pune, has revealed that domestic animals are positive for anti-IgG antibody in at least 15 districts of Gujarat state (NIV unpublished data). Though the main endemic foci are in Gujarat state, CCHF has been suspected in other parts of the country, based on earlier serology data., Strengthening of public health system networking forreporting and circulating information, with participation and education of the generaľpublic in the countiy, is required to deal with these deadly diseases.
| Conclusion|| |
KFD and CCHF are both of high importance for public health in India, as cases are observedalmost every year in Karnataka and Gujarat states, respectively. It is important that the health system should be able to distinguish these tick-borne haemorrhagic diseases from other diseases, which have diverse and often overlapping, clinical presentations. In general, as the incidence of tick-borne diseases increases in any area, surveillance in other/adjoining geographic areas shouid also be expanded. Keeping in view the current status, the Indian Council of Medical Research (ICMR) has taken the initiative to survey to determine the probability of the existence of KFD in states adjoining Karnataka. Similarly, a joint initiative has been taken up byĪCMR and the Indian Council of Agricultural Research (ICAR) to conduct a survey of IgG antibodies against CCHF in domestic animals in different states of India. In view of the “One health concept” put forward by WHO, it is proposed to establish a joint ICMR and ICAR committee on zoonoses, to create facilities for an ICMR–ICAR centre of excellence on zoonoses, which will be upgraded to a National Institute of Zoonoses. This institute W111 be dedicated to research and development in the areas of zoonotic diseases and will significantly contribute towards early diagnosis and control of re-emerging and newly emerging zoonotic diseases.
| Acknowledgements|| |
We gratefully acknowledge the encouragement and support extended by Dr VM Katoch, Secretary, Department of Health Research, Ministry of Health and Family Welfare, New Delhi. We also gratefully acknowledge the cooperation of the Directorate of Health Services, Government of Gujarat, Integrated Disease Surveillance Programme, and authorities of National Vector Borne Disease Control Programme and the State Health Department, Karnataka, and Viras Diagnostic Laboratory, Shimoga, Karnataka.
Source of Support: Nil.
Conflict of Interest: None declared.
Contributorship: : DTM and PDY contributed to the study design and drafted the manuscript as the lead writers. PDY collated and summarized the collected data and DYP carried out extensive systematic review of the literature about Kyasanur forest disease and Crimean-Congo haemorrhagic fever on different databases, and helped in preparing the draft. All the authors were involved in revising the manuscript.
| References|| |
Sonenshine DE. Biology of ticks. Vol 1. New York: Oxford University Press, 1991.
Jongejan F, Uilenberg G. The global importance of ticks. Parasitology. 2004;129(Suppl l):S3-S14.
Parola P, Raoult D. Ticks and tickborne bacterial diseases in humans: an emerginginfectiousthreat. Clin. Infect. Dis. 2001;32:897–928.
Nicholson WL, Allen KE, McQuiston JH, Breitschwerdt EB, Little SE. The increasing recognition of rickettsial pathogens in dogs and people. Trends Parasitol. 2010;26:205–212.
Piesman J, Eisen L. Prevention of tick-borne diseases. Annu. Rev. Entomol. 2008; 53:323–343.
Burgdorfer w, Barbour AG, Hayes SF, Benach JL, Grunwaldt E, Davis JP. Lyme disease -atick-borne spirochetosis. Science. 1982; 216:1317–1319.
Jongejan F, Uilenberg G. The global importance of ticks. Parasitol. 2004;129:S1-S12.
Kjemtrup AM, Conrad PA. Human babesiosis: an emerging tick-borne disease. Int. J. Parasitol. 2000;30:1323–1337.
Yadav PD, Gurav YK, Mistry M, Shete AM, Sarkale P, Deoshatwar AR, Unadkat VB, Kokate P, Patil DY Raval DK, Mourya DT. Emergence of Crimean-Congo hemorrhagic fever in Amreli District of Gujarat state, India, June to July 2013. Int. J. Infect. Dis. 2013 Jan;18:97–1000. http:// dx.doi.org/10.1016/j.ijid.2013.09.019
- accessed 15 March 2014.
Mourya DT, Yadav PD, Sandhya VK, Reddy S. Spread of Kyasanur Forest disease, Bandipur Tiger Reserve, India, 2012–2013. Emerg. Infect. Dis. 2013; 19:1540–1541.
Geevarghese G, MishraAC. Haemaphysalis ticks of India. ist Edition. ElsevierPub, 2011.
Ghosh S, Azhahianambi P, Fuente J. Control of ticks of ruminants, with special emphasis on livestock farming systems in India: present and future possibilities for integrated control—a review. Experiment. Appl. Acarol. 2006;40:49–66.
Yadav PD, Raut CG, Patil DY, Majumdar TD, Mourya DT. Crimean-Congo hemor-rhagic fever: current scenario in India. Proc. Natl. Acad. Sci. India Sect. B. Biol. Sci. 2014 Mar;84(1):9–18. http://dx.doi. org/10.1007/s40011-013-0197–3
- accessed 16 March 2014.
Lahariya C, Goel MK, Kumar A, Puri M, Sodhi A. Emergence of viral hemorrhagic fevers: is recent outbreak of Crimean-Congo hemorrhagic fever in India an indication? J. Postgrad. Med. 2012;58:39–6.
Work TH, Trapido H. Summary of preliminary report of investigations of the virus research centre on an epidemic disease affecting forest villagers and wild monkeys in Shimoga district, Mysore. Indian J. Med. Sci. 1957; 11:340–341.
Trapido H, Rajagopalan PK, Work TH, Varma MG. Kyasanur Forest disease. VIII. Isolation of Kyasanur forest disease virus from naturally infected ticks of the genus Haemaphysalis
. Indian J Med Res. 1959;47:133–138.
Work TH, Trapido H. Summary of preliminary report of investigations of the virus research centre on an epidemic disease affecting forest villagers and wild monkeys in Shimoga district, Mysore. Indian J. Med. Sci. 1957;11:340–341.
Verma MG, Webb HE, Pavri K. studies on the transmission of Kyasanur Forest disease virus by Haemaphysalis spinigera
Newman. Transfusion (Paris). 1960;54:509–516.
Singh KR, Pavri K, Anderson CR. Experimental Transovarial Transmission of Kyasanur Forest Disease Virus in Haemaphysalis Spinigera
. Nature. 1963;199:513.
Singh KR, Pavri K, Anderson CR. Transmission of Kyasanur Forest disease byHaemaphysalis tururis,Haemaphysalispapuanakinneari
and Haemaphysalis minuta
. Ind. J. Med. Res. 1964;52:566–573.
Bhat HR, Sreenivasan MK, Goverdhan MK, Naik SV. Transmission of Kyasanur Forest disease virus by Haemaphysalis Kyasanurensis Trapido
, Hoogstraal and Rajagopalan, 1964 (Acarina : Ixodidae
) . Ind. J. Med. Res. 1975;63:879–887.
Singh KR, Bhatt PN. Transmission of Kyasanur Forest disease virus by Hyalomma marginatum isaaci
. Ind. J. Med. Res. 1968;56:610–613.
Singh KR, Goverdhan MK, Rao TR. Experimental transmission of Kyasanur forest disease virus to small mammals by Ixodes petauristae
and Haemaphysalis spinigera
. Ind. J. Med. Res. 1968;56:594–609.
Boshell J, Rajagopalan PK, Patil AP, Pavri KM. Isolation of Kyasanur Forest disease virus from ixodid
ticks: 1961–1964. Ind. J. Med. Res. 1968;56:541–568.
Singh KR, Goverdhan MK, Bhat UK. Transmission of Kyasanur Forest disease virus by soft tick, Argaspersicus
) . Ind. J. Med. Res. 1971;59:213–218.
Bhat UK, Goverdhan MK. Transmission of Kyasanur Forest disease virus bythe softtick, Ornithodoros rossi
Boshell J, Rajagopalan PK. Preliminary studies on experimental transmission of Kyasanur Forest disease virus by nymphs of Ixodes petauristae
Warburton, 1933, infected as larvae on Suncus murinus
and Rattus blanfordi
. Ind. J. Med. Res. 1968;56:589–593.
TrapidoH. KyasanurForestdisease: anewinfectionofmanandmonkeys in tropical India by a virus of the Russian spring summer-complex. Proceedings of the Nin th Pacific Science Congress. 1957;17:80–84.
Banerjee K. Kyasanur Forest disease. In: Monath TP. Editor. Arboviruses: epidemiology and ecology. Boca Raton (FL): CRC Press. 1990. pp. 93–116.
Pattnaik p. Kyasanur forest disease: an epidemiological view in India. Rev. Med. Virol. 2006;16:151–65.
Sarkar JK, Chatterjee SN. Survey of antibodies against arthropod-borne viruses in the human sera collected from Calcutta and other areas of West Bengal. Indian J Med Res. 1962;50:833–841.
Padbidri VS, Wairagkar NS, Joshi GD, Umarani UB, Risbud AR Gaikwad DL, Bedekar SS, Divekar AD, Rodrigues FM. A serological survey of arboviral diseases among the human population of the Andaman and Nicobar Islands, India. Southeast Asian J Trop Med Public Health. 2002;33:794–800.
Kasabi GS, Murhekar MV, Yadav PD, Raghunandan R, Kiran SK, Sandhya VK, et al. Kyasanur Forest disease, India, 2011–2012. Emerg. Infect. Dis. 2013;19:278–82.
Mehla R, Kumar SR, Yadav P, Barde PV, Yergolkar PN, Erickson BR, Carroll SA, Mishra AC, Nichol ST, Mourya DT. Recent ancestry of Kyasanur Forest disease virus. Emerg Infect Dis. 2009;15:1431–1437.
Dodd KA, Bird BH, Khristova ML, Albarino CG, Carroll SA, Comer JA, Erickson BR, Rollin PE, Nichol ST. Ancient ancestry of KFDV and AHFV revealed by complete genome analyses of viruses isolated from ticks and mammalian hosts. PLoS Negl Trop Dis. 2011;5:el352.
Mourya DT, Yadav PD, Mehla R, Barde PV, Yergolkar PN, Thakare J.p. et al
. Diagnosis of Kyasanur Forest disease by nested RT-PCR, real-time RT-PCR and IgM capture ELISA. J Virol Methods. 2012;186:49–54.
Dandawate CN, Desai GB, Achar TR, Banerjee K. Field evaluation of formalin inactivated Kyasanur Forest disease virus tissue culture vaccine in three districts of Karnatakastate. Ind. J. Med. Res. 1994;99:152–8.
Jaureguiberry S, Tattevin P, Tarantola A, Legay F, Tall A, Nabeth p et al. Imported Crimean-Congo hemorrhagic fever. J. Clin. Microbiol. 2005;43:4905–907.
Simpson DI, Knight EM, Courtois G, Williams MC, Weinbren MP, Kibukamusoke JW. Congo virus: a hitherto undescribed virus occurring in Africa. I. Human isolations-clinical notes. East Afr. Med. J. 1979;44:86–92.
Williams M, Tukei PM, Lule M, Mujomba E, Mukuye A. Virology: identification studies. Rep. E. Afr. Virus. Res. Inst. 1966;16:24–26.
Chumakov MP, Butenko AM, Shalunova NV, Martyanova LI, Smirnova WE, Bashkirtsev VN et al. New data on the virus causing Crimean hemorrhagic fever (CHF). VoprVirusol. 1968;3:377 (in Russian; in English, NAMRU3-T596).
Ergonul O. Crimean-Congo haemorrhagic fever. Lancet Infect. Dis. 2006;6:203–214.
Mourya DT, Yadav PD, Shete AM, Gurav YK, Raut CG, Jadi RS, et al. Detection, isolation and confirmation of Crimean-Congo hemorrhagic fever virus in human, ticks and animals in Ahmadabad, India, 2010–2011. PLoS. Negl. Trop. Dis. 2012;6:el653.
Whitehouse C.A. Crimean-Congo hemorrhagic fever. Antivir. Res. 2004;64:145–160.
Gordon SW, Lin thicum KJ, Moulton JR. Transmission of Crimean-Congo hemorrhagic fever virus in two species of Hyalomma ticks from infected adults to CO feeding immature forms. Am. J. Trop. Med. Hyg. 1993;48:576–580.
Zeller HG, Cornet JP, Camicas JL. Experimental transmission of Crimean-Congo hemorrhagic fever virus by west African wild ground-feeding birds to Hyalommamarginatum rufipes ticks. Am. J. Trop. Med. Hyg. i994;50:676–681.
Logan TM, Lin thicum KJ, Bailey CL, Watts DM, Moulton JR. Experimental transmission of Crimean-Congo hemorrhagic fever virus by Hyalommatruncatum Koch. Am. J. Trop” Med. Hyg. 1989;40:207–212.
Dohm DJ, Logan TM, Lin thicum KJ, Rossi CA, Turell MJ. Transmission of Crimean-Congo hemorrhagic fever virus by Hyalomma impeltatum (Acari:Ixodidae) after experimental infection. J. Med. Entomol. 1996;33:848–851.
Shepherd A.J, Swanepoel R, Cornel A.J, Mathee O. Experimental studies on the replication and transmission of Crimean-Congo hemorrhagic fever virus in some African tick species. Am. J. Trop. Med. Hyg. 1989;40:326–331.
Bakheit MA, Latif AA, VatanseverZ, Seitzer U, Ahmed J. The huge risks due to hyalomma ticks. In: Arthropods as vectors of emerging diseases. Heinz Mehlhorn. Ed. Springer pub. pp.168.
LATIF AA. Tick (Acari: Ixodoidea: Ixodidae
) immature feeding on cattle, camels and sheep in the Sudan, with notes on behaviour of Hyalomma anatolicum anatolicum larvae fed on different hosts. Insect Sci.Applicat. 1985;6:59–61.
Vorou, R.; Pierroutsakos, I.N.; Maltezou, H.C. Crimean-Congo hemorrhagic fever. Curr. Opin. Infect. Dis. 2007;20:495–500.
Shepherd, A.J.; Leman, P.A.; Swanepoel, R. Viremia and antibody response of small African and laboratory animals to Crimean-Congo hemorrhagic fevervirus infection. Am. J. Trop. Med. Hyg. 1989;40:541–547.
Shepherd AJ, Swanepoel R, Shepherd SP, McGillivray GM, Searle LA. Antibody to Crimean-Congo hemorrhagic fever virus in wild mammals from southernAfrica. Am. J. Trop. Med Hyg. 1987;36:133–142.
Palomar AM, Portillo A, Santibanez P, Mazuelas D, Arizaga J, et al. Crimean-Congo hemorrhagic fever virus in ticks from migratory birds, Morocco. Emerg. Infect. Dis. 2013;19:260–263. DOI: 10.3201/ eidl902.121193.
Mishra AC, Mehta M, Mourya DT, Gandhi S. Crimean-Congo haemorrhagic fever in India. Lancet. 2011;378:372.
Flick R, Whitehouse CA. Crimean-Congo hemorrhagic fever virus. Curr Mol Med. 2005; 5:753–760.
Tahmasebia F, Ghiasib SM, Mostafavib E, Moradib M, Piazakc N, Mozafarid A, et al. Molecular epidemiology of Crimean- Congo hemorrhagic fever virus genome isolated from ticks of Hamadan province of Iran. J Vector Borne Dis. 2010;47:211–216.
Olschlager S, Gabriel M, Schmidt-Chanasit J, Meyer M, Osborn E, CongerNG, Allan PF, Gunther S. Complete sequence and phylogenetic characterization of Crimean-Congo hemor- rhagic fever virus from Afghanistan. J Clin Virol. 2011;50”90-92, 753.
Altaf A, Luby S, Ahmed AJ, Zaidi N, Khan AJ. Outbreak of Crimean-Congo haemorrhagic fever in Quetta, Pakistan: con- tact tracing and risk assessment. Trop Med Int Health. 1998;3:878–882.
Whitehouse CA, Hottel H, Deniz A, VatanseverZ, Ergonul O, Paragas J, et al. Molecular detection of Crimean Congo hemorrhagic fever virus in ticks from Turkey. American Society of Tropical Medicine and Hygiene, 55th Annual Meeting, Atlanta, November 12–16, 2006.
Ergonul O, Celikbas A, Dokuzoguz B, Eren S, Baykam N, Esener H. Characteristics of patients with Crimean-Congo hem- orrhagic fever in a recent outbreak in Turkey and the impact of oral ribavirin therapy. Clin Infect Dis. 2004;39:284–287.
Chinikar S, Persson SM, Johansson M, Bladh L, Goya M, Houshmand B et al. Genetic analysis of Crimean-Congo hemorrhagic fever virus in Iran. J Med Virol. 2004; 73(3):404–411.
Begum F, Wisseman CL, Casals J. Tick-borne viruses of West Pakistan. IV. Viruses similar to or identical with, Crimean hemorrhagic fever (Congo-Semunya), Wad Medani and Pak Argas 461 isolated from ticks of the Changa Manga Forest, Lahore District, and of Hunza, Gilgit Agency, W. Pakistan. Am J Epidemiol. 1970;92:197–202.
Burney M.I., Ghafoor A., Saleen M., Webb P.A., Casals J. Nosocomial outbreak of viral hemorrhagic fever caused by Crimean hemorrhagic fever-Congo virus in Pakistan, January 1976. Am J Trop Med Hyg. 1980;29:941–947.
Junaid Saleem, Muhammad Usman, Ahmad Nadeem, Shakeel Afzal Sethi, Muhammad Salman;Crimean-Congo hemorrhagic fever: a first case from Abbottabad, Pakistan. International. Journal of Infectious diseases. 2009;13(3):121–123.
Wallace MR, Hale BR, UteGC, Olson PE, Earhart KC, Thornton SA, et al. Endemic infectious diseases of Afghanistan. Clin Infect Dis. 2002;34(suppl 5):S171-S207.
Mofleh J, Ahmad AZ. Crimean-Congo haemorrhagic fever outbreak investigation in the Western Region of Afghanistan in 2008. Eastern Mediterranean Health Journal. 2012;18:522–526.
Sureau R Klein JM. Casals J, et al. Isolation of Thogoto, wad medani, wanowrie, and Crimean-Congo hemorrhagic fever viruses from ticks of domestic animals in Iran. AnnVirol (Inst Pasteur). 1980;131:185–200.
Izadi S, Holakouie-Naieni K, Majdzadeh SR, Chinikar S, Nadim A, Rakhshani F, Hooshmand B: Seroprevalence of Crimean-Congo hemorrhagic fever in Sistan-va-Baluchestan province of Iran. Jpn J Infect Dis”2006;59(5):326–328.
Tang Q, Prehaud C, Bouloy M, Conghui F, Xiuqing Z, Huaxin C, Sequencing and analysis of S gene segment of XHFV. Chin J Microbiolimmunol. 1999; 19:461–5.
Papa A, Benjiang Ma, Sophie Kouidou, Qing Tang, Changshou Hang, Antonis Antoniadis. Genetic characterization of the M RNAsegment of Crimean Congo hemorrhagic fever virus strains, China. Emerg. Infect. 2002;8(1):50–53.
Rodrigues FM, Padbidri VS, Ghalsasi GR, Gupta NP, Mandke VB. Prevalence of crimean haemorrhagic-Congo virus in Jammu and Kashmir state. Indian J Med Res. 1986;84:134–138.
Shanmugam J, Smirnova SE, Chumakov MP. Presence of antibodies to arboviruses of the Crimean haemorrhagic fever Congo (CHF-Congo) group in human being and domestic animals in India. Indian J Med Res. 1976;64:1403–1413.
Yadav PD, Raut CG, Mourya DT. Re-occurrence of Crimean-Congo haemorrhagic fever in Ahmedabad, Gujarat, India (2012): a fatal case report. Indian J Med Res. 2013;138:1027–1028.
Anagnostou V, Papa A. Evolution of Crimean-Congo hemorrhagic fever virusinfection. Genet Evol. 2009;9:948–954.
Burt FJ, Swanepoel R. Molecular epidemiology of African and Asian Crimean-Congo haemorrhagic fever isolates. Epidemiol Infect. 2005;133:659–566.
Deyde VM, Khristova ML, Rollin PE, Ksiazek TG, Nichol ST. Crimean-Congo hemorrhagic fever virus genomics and global diversity. J Virol. 2006;80:8834–8842.
Carroll SA, Bird BH, Rollin PE, Nichol ST. Ancient common ancestry of Crimean-Congo hemorrhagic fever virus. Mol Phylo Evol. 2010;55:1103–1110.
Hewson R, Chamberlain J, Mioulet V, Lloyd G, Jamil B, Hasanb R, et al. Crimean-Congo hemorrhagic fever virus: sequence analysis of the small RNA segments from a collection of viruses world-wide. Virus Res. 2004;102:185–189.
Yadav PD, Cherian SS, Zawar D, Kokate P, Gunjikar R, Jadhav S, et al. Genetic characterization and molecular clock analyses of the Crimean-Congo hemorrhagic fever virus from human and ticks in India, 2010–2011. Infect Genet Evol. 2013 Mar;14:223–31. doi:10.1016/j! meegid.2012.10.005.
Watts DM, Ksiasek TG, Lin thicum KJ, Hoogstraal H. Crimean-Congo hemorrhagic fever. In: Monath TP. Editor. The arboviruses: epidemiology and ecology. Boca Raton, FL: CRC Press, 1988.
Swanepoel R, Gill DE, Shepherd AJ, Leman PA, Mynhardt JH, Harvey S. The clinical pathology of Crimean-Congo hemorrhagic fever. Rev Infect Dis. 1989;ll:(Suppl 4):S794-S800.
Shepherd AJ, Swanepoel R, Gill DE. Evaluation of enzyme-linked immunosorbent assay and reversed passive hemagglutination for detection of Crimean-Congo hemorrhagic fever virus antigen. J. Clin. Microbiol. 1988;26:347–353.
Burt FJ, Leman PA, Abbott JC, Swanepoel R. Serodiagnosis of Crimean-Congohaemorrhagicfever. Epidemiol. Infect. 1994;113: 551–562.
Drosten C, Kummerer BM, Schmitz H, Gunther S. Molecular diagnostics of viral hemorrhagic fevers. Antiviral Res. 2003;57:61–87.
Schwarz TF, Nsanze H, Longson M, Nitschko H, Gilch S, Shurie H, et al. Polymerase chain reactionfor diagnosis and identification of distinct variants of Crimean-Congo haemorrahgic fever virus in the United Arab Emirates. Am. J. Trop. Med. Hyg.l996;55:190–196.
Ergonul O, Celikbas A, Dokuzoguz B, Eren S, Baykam N, Esener H. Characteristics of patients with Crimean-Congo hemorrhagic fever in a recent outbreak in Turkey and impact of orai ribavirin therapy. Clin. Infect. Dis. 2004;39:284–287.
Mardani M, Jahromi MK, Naieni KH, Zeinali M.The efficacy of oral ribavirin in the treatment of Crimean-Congo hemorrhagic fever in Iran. Clin. Infect. Dis. 2003;36:1613–1618.
Fisher-Hoch SP, Khan JA, Rehman S, Mirza S, Khurshid M, McCormick JB. Crimean- Congo hemorrhagic fever treated with oral ribavirin. Lancet. 1995;346:472–475.
Tignor GH, Hanham CA. Ribavirin efficacy in an in vivo model of Crimean-Congo hemorrhagic fever virus (CCHF) infection. Antiviral Res. 1993;22:309–325.
Watts DM, Ussery MA, Nash D, Peters CJ. Inhibition of Crimean-Congo hemorrhagic fever viral infectivity yields in vitro by ribavirin. Am. J. Trop. Med” Hyg. 1989;41:581–585.
Shepherd AJ, Swanepoel R, Leman PA. Antibody response in Crimean-Congo hemorrhagic fever. Rev. Infect. Dis. 1989;ll:S801–806.
Schreck CE, Snoddy EL, Spielman A. Pressurized sprays of permethrin or deet on military clothing for personal protection against Ixodes dammini (Acari: Ixodidae). J?Med. Entomol.l986;23: 396–9.
Patel AK, Patel KK, Mehta M, Parikh TM, Toshniwal H, Patel K. First Crimean-Congo hemorrhagic fever outbreak in India. JAssoc Physicians India. 2011;59:585–589.
Gambel JM, Brundage JF, Kuschner RA, Kelley PW. Deployed US army soldiers’ knowledge and use of personal protection measuresto prevent arthropod-related casualties. J. Travel Med. 1998;5:217–20.
Ho-Pun-Cheung T, Lamarque D, Josse R, et al. Protective effect of clothing impregnated with permethrin against D. reticulatus and D. Bull. Soc. Pathol’ Exot.l999;92:337–40.
Ergonul O, Whitehouse CA. Risk groups and control measures for crimean-congo hemorrhagic fever. In: Ergonul O, Whitehouse CA. Editors. Crimean-Congo hemorrhagic fever: a global perspective. Dordrecht: Springer, 2007. pp. 273–280.
Wiwanitkit V, Singh MY. Emerging infectious diseases in India. New York: Nova Science Publishers, 2009.
Greger, M. The human/animal interface: emergence and resurgence of zoonotic infectious diseases. Crit. Rev. Microbiol. 2007;33:243–299.
KilpatrickAM, Randolph SE. Drivers, dynamics, and control of emerging vector-borne zoonotic diseases. Lancet. 2012;380(9857):1946–55.
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]
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