Kyasanur Forest Disease Research Articles

Development of a quantitative real-time RT-PCR assay that differentiates between Kyasanur Forest disease virus and Alkhurma hemorrhagic fever virus

Kyasanur Forest disease virus (KFDV) and Alkhurma hemorrhagic fever virus (AHFV) are enveloped, positive-stranded RNA viruses of clinical importance with complex enzootic life cycles involving hematophagous ticks which feed on small and large mammals. Humans and monkeys are dead-end hosts for these viruses. Recent trends in epidemiological data suggest both virus incidences are steadily increasing and their geographical distribution expanding out of previously known circulation regions. For the detection and discrimination of these two closely related flaviviruses, we have developed quantitative real-time RT-PCR assays with 100 % sensitivity and 100 % specificity for KFDV, 100 % sensitivity and 99.4 % specificity for AHFV as determined using 550 clinical samples collected between 2015–2018 from Western Ghats region of India. This rapid and sensitive assay will enable researchers to accurately diagnose the presence of the virus during viremia in human and animal blood samples, and also from tick specimens. Incorporation of these new tests into a routine diagnosis will help in the diagnosis of KFDV as well as AHFV in the endemic areas and also would provide an early warning of the spread of this virus to newer regions with similar epidemiology.

Geographic distribution of Tick-borne encephalitis virus complex.

A comprehensive understanding of the geographic distribution of the tick-borne encephalitis virus (TBEV) complex is necessary due to increasing transboundary movement and cross-reactivity of serological tests. This review was conducted to identify the geographic distribution of the TBEV complex, including TBE virus, Alkhurma haemorrhagic fever virus, Kyasanur forest disease virus, louping-ill virus, Omsk haemorrhagic fever virus, and Powassan virus. Published reports were identified using PubMed, EMBASE, and the Cochrane library. In addition to TBEV complex case-related studies, seroprevalence studies were also retrieved to assess the risk of TBEV complex infection. Among 1406 search results, 314 articles met the inclusion criteria. The following countries, which are known to TBEV epidemic region, had conducted national surveillance studies: Austria, China, Czech, Denmark, Estonia, Finland, Germany, Hungary, Italy, Latvia, Norway, Poland, Romania, Russia, Switzerland, Sweden, Slovenia, and Slovakia. There were also studies/reports on human TBEV infection from Belarus, Bulgaria, Croatia, France, Japan, Kyrgyzstan, Netherland, and Turkey. Seroprevalence studies were found in some areas far from the TBEV belt, specifically Malaysia, Comoros, Djibouti, and Kenya. Kyasanur forest disease virus was reported in southwestern India and Yunnan of China, the Powassan virus in the United States, Canada, and east Siberia, Alkhurma haemorrhagic fever virus in Saudi Arabia and east Egypt, and Louping-ill virus in the United Kingdom, Ireland, and east Siberia. In some areas, the distribution of the TBEV complex overlaps with that of other viruses, and caution is recommended during serologic diagnosis. The geographic distribution of the TBEV complex appears to be wide and overlap of the TBE virus complex with other viruses was observed in some areas. Knowledge of the geographical distribution of the TBEV complex could help avoid cross-reactivity during the serologic diagnosis of these viruses. Surveillance studies can implement effective control measures according to the distribution pattern of these viruses.

India to envision One Health movement for confronting emerging health threats: From concept to approach toward institutionalization

The author's key role in advocating and leading One Health (OH) initiatives in India (especially in Kerala), review the need for and progress of OH from concept to approach and proposes its institutionalization as the way forward. India is currently facing many health threats such as antimicrobial resistance, environmental health hazards, and food safety risks and most importantly, zoonotic diseases such as Nipah, Avian Influenza, Scrub typhus, Congo fever, Kyasanur forest disease, COVID-19, and leptospirosis that grossly impact country's economy. The recent pandemics had exposed the gaps in public health policy and government is prepared to commit on the OH approach and to invest more on public health infrastructure. Further, as challenges have increased in recent years, OH approach was clearly advocated by the experts not only to cope up the pandemic but also to manage the infodemic by promoting the timely dissemination of accurate information. Right from the endorsement of OH in 2007 by India's Prime minister to the present fight against COVID-19 pandemic, the actions to control and manage the disease was ideally oriented toward a collaborative approach. Last year (2019), the representatives from relevant ministries and department had a ground-breaking dialog to develop charter and constitute a National policy on OH. Recently, Health Ministers of the Member States of the World Health Organization South-East Asia signed "Delhi declaration" where the key essence was to implement intersectoral coordination mechanisms following the "OH" approach. India's future policy intervention will emphasize on strengthening of integrated public health labs and contributing to building a national institutional platform for OH to boost research initiatives. Taking stock of OH happenings, resources, challenges, and priorities, the implementation strategy has been proposed across human, animal and environmental health. The article further highlights the key areas that need OH intervention in India, the country's progress in OH and the success stories of OH for a sustainable action to confront emerging health threats.

Epidemic retinitis and community outbreaks.

Purpose:The objective of this study was to correlate seasonal variation of epidemic retinitis (ER) with concurrent community outbreaks.Methods:This is a retrospective, observational, comparative study conducted in a tertiary care eye hospital in south India. Monthly variation in number of ER cases in comparison with reported community outbreaks by Integrated Disease Surveillance Program (IDSP) from 2009 to 2020 in the same region were studied. Month-wise graphs against number of patients were plotted for ER and for each community outbreak.Results:ER was diagnosed in 163 patients. Diagnosis of presumed rickettsial ER was made in 48 cases (29.44%), chikungunya in 5, dengue in 3 and typhoid in 6 cases, while in other cases the etiological diagnosis remained uncertain (n = 101). Multiple positive serological tests were seen in 6 patients (Weil Felix Test (WFT) with WIDAL in 4 and chikungunya IgM with WFT in 2 patients). Relevant reported outbreaks by IDSP were: Pyrexia of unknown origin (PUO) (n = 5148), Chikungunya (n = 6577), Dengue (n = 7350), Measles (n = 1422), Mumps (n = 881), Rubella (n = 288), Malaria (n = 2262), Chicken Pox (n = 2385), Typhoid (n = 597), Kyasanur Forest Disease (n = 381), Scrub Typhus (n = 13), Typhus fever (n = 4), Japanese Encephalitis (n = 15). None of the outbreak graphs pattern was identical or similar to the graph of ER. Inverse relation of the graph of dengue outbreak with ER was observed.Conclusion:Inverse correlation between dengue and ER should be further studied for causation, which we believe may prove dengue as least common cause. Reporting of rickettsial outbreaks should be enhanced by undertaking statewide awareness and procurement of gold standard tests.

Kyasanur Forest Disease vaccination coverage and its perceived barriers in Goa, India-A mixed methods operational research.

Kyasanur Forest Disease (KFD) is a highly infectious viral illness transmitted by infected ticks through contact with monkeys and other forest animals. Till date there is no definite treatment available for KFD. Hence, vaccination is considered to be an important public health intervention to control KFD. This study aimed at estimating the vaccination coverage for primary and booster doses of KFD vaccine and exploring the perceived barriers to vaccination in the affected villages of Goa, India during 2015-18. In this explanatory mixed methods study, vaccine coverage was estimated bydata obtained from the KFD vaccination registers maintained at the health centers catering to the KFD affected villages. To understand the barriers to vaccination,key informant interviews were conducted among implementing health officers, medical officers and nurses involved in vaccination. Perceptions of vaccinees and community members were studied through in-depth interviews and focus group discussions. Out of the 35,500 targeted population (6-65 years)for KFD vaccination, 32% received one dose and 13.2% received two doses. The coverage for first booster and annual booster was 4.9% and 0.5% respectively. The drop out from first to second and third doses was 57% and 85% respectively. 69% of doses were delivered during community outreach programmes and remaining at health facilities. Inadequate vaccine stock, inappropriate timing of vaccination campaign, lack of awareness and misconceptions related to indications of vaccines, travel distance for follow up doses given at community health centre and pain due to injection were perceived as reasons for poor vaccination coverage. KFD vaccination coverage was poor in the villages affected by KFD in Goa. Both left-out and drop-out phenomena were observed in KFD vaccination. Vaccine implementation plan has to consider suitable time for the local people, maintain adequate vaccine stock and encourage community-based vaccination campaigns instead of facility-based to achieve optimal vaccine coverage.

Forest loss shapes the landscape suitability of Kyasanur Forest disease in the biodiversity hotspots of the Western Ghats, India.

Anthropogenic pressure in biodiversity hotspots is increasingly recognized as a major driver of the spillover and expansion of zoonotic disease. In the Western Ghats region of India, a devastating tick-borne zoonosis, Kyasanur Forest disease (KFD), has been expanding rapidly beyond its endemic range in recent decades. It has been suggested that anthropogenic pressure in the form of land use changes that lead to the loss of native forest may be directly contributing to the expanding range of KFD, but clear evidence has not yet established the association between forest loss and KFD risk. The current study sought to investigate the relationship between KFD landscape suitability and both forest loss and mammalian species richness, to inform its epidemiology and infection ecology. A total of 47 outbreaks of KFD between 1 January 2012 and 30 June 2019 were modelled as an inhomogeneous Poisson process. Both forest loss [relative risk (RR) = 1.83; 95% confidence interval (CI) 1.33-2.51] and mammalian species richness (RR = 1.29; 95% CI 1.16-1.42) were strongly associated with increased risk of KFD and dominated its landscape suitability. These results provide the first evidence of a clear association between increasing forest loss and risk for KFD. Moreover, the findings also highlight the importance of forest loss in areas of high biodiversity. Therefore, this evidence provides strong support for integrative approaches to public health which incorporate conservation strategies simultaneously protective of humans, animals and the environment.

Kyasanur Forest Disease: Vector Surveillance and its Control

Kyasanaur Forest Disease (KFD) is a tick-borne viral hemorrhagic fever caused by KFD Virus (KFDV), a member of the virus family Flaviviridae (Genus: Flavivirus). KFD was first recognized as a febrile illness in Shimoga district of Karnataka state, India in 1957. It is also called as monkey fever. KFDV gets transmitted by the bite infective ticks Haemaphysalis spp., especially at its nymphal stage. There is wide range of hosts including human, tick species, rodents (shrews, forest rats) monkeys (black faced langurs and red faced bonnet monkeys), bats, squirrels, ground dwelling birds and porcupines and domestic ruminants. Rodents are the best maintenance hosts (short generation time). In KFD, Human act as dead end host. They do not develop adequate viremia to infect the ticks. Amplification of virus occurs in Monkeys. Domestic ruminants maintain the infected tick population for long time. Trans-stadial transmission in ticks is common, but trans-ovarial transmission is absent except in Ixodes petaurisae. About sixteen species of ticks are known to be involved in transmission. Ten species carry natural infection. Haemaphysalis spinigera and Haemaphysalis turturis are the two major vector playing role in KFD transmission. Other species of Haemaphysalis involved in transmission of KFDV are H. aculeata, H. bispinosa, H. cuspidata, H. kyasanurinsis and H. minuta, H. kinneari and H. wellingtoni. An attempt has been made in this manuscript to discuss the vector surveillance in KFD transmission and vector control options available at present.

Partnership in Surveillance: A Kerala model to Emerging Public Health Threats.

Partnership in Surveillance: A Kerala model to Emerging Public Health Threats.

Growth Kinetics of Kyasanur Forest Disease Virus in Mammalian Cell Lines and Development of Plaque Reduction Neutralization Test.

Kyasanur forest disease virus (KFDV) is a tick-borne flavivirus identified in 1957 in the Karnataka state of India causing fatalities in monkeys and humans. Even after the introduction of a vaccine in the endemic areas, hundreds of cases are reported every year. Being a high-risk category pathogen, the studies on this virus in India were limited till the past decade. The growth characteristics of this virus in various mammalian cell lines have not yet been studied. In this study, we have demonstrated the growth pattern of virus in BHK-21, Vero E6, Vero CCL81, rhabdomyosarcoma, porcine stable kidney, and Pipistrellus ceylonicus bat embryo cell lines, and found BHK-21 to be the best. We have developed KFDV plaque reduction neutralization test for the first time.

Out-Break of Kyasanur Forest Disease: A Review Article

Out-Break of Kyasanur Forest Disease: A Review Article

Spatial distribution of Haemaphysalis species ticks and human Kyasanur Forest Disease cases along the Western Ghats of India, 2017-2018.

Kyasanur Forest Disease (KFD) is a viral haemorrhagic fever, transmitted to humans and other hosts by a tick vector of genus Haemaphysalis. It affects 400-500 people annually in the Western Ghats region of India through spring to summer season. To understand the species composition, distribution, and abundance of Haemaphysalis ticks in endemic taluks (sub-districts) of India, a surveillance for ticks was conducted between October 2017 and January 2018. In total 105 sites were selected based on grid sampling from five taluks representing five KFD endemic states in south India. A sum of 8373 ticks were collected by using standard flagging method. The study showed a wide distribution of host seeking tick species among the selected taluks, wherein Haemaphysalis spinigera was predominant in 3/5 taluks, Haemaphysalis bispinosa in 1/5 taluks, and both the species in 1/5 taluks. Further, the H. spinigera abundance was categorised and compared with the incidence of human cases during the same season. The grids with very high and high H. spinigera abundance had 70% of the 205 human cases reported. This method of tick surveillance could be efficiently used as a standard model for KFD transmission risk assessment and prediction of impending outbreaks.

Historical Expansion of Kyasanur Forest Disease in India From 1957 to 2017: A Retrospective Analysis.

A highly infectious tick‐borne virus causes Kyasanur Forest disease (KFD), which has been expanding in recent decades in India. Current studies do not provide an updated understanding of the disease trends and its expansion in India. We address this gap in the literature through a detailed review to reveal the annual historic expansion of KFD cases across the span of years from 1957 to 2017. In addition, we explore the factors that may have led to the geographic expansion of KFD. The annual numbers of cases of KFD among humans are estimated using peer‐reviewed journal articles, Pro‐MED database, historical and archived newspapers, and government reports, technical reports, publications, and medical websites. From 1957 to 2017, there were an estimated 9,594 cases of KFD within 16 districts in India. The most significant human outbreaks of the disease were in the years 1957–1958 (681 cases), 1983–1984 (2,589 cases), 2002–2003 (1,562 cases), and 2016–2017 (809 cases). In 2015, KFD appeared in Goa. In 2016, new cases emerged in Belgaum, a district in Karnataka state, and in the Sindhudurg district in Maharashtra state. The processes by which KFD persists and spreads are not clear, but demographic, socioeconomic, political, and environmental factors seem to play a role.

Distribution and prevalence of ticks on livestock population in endemic area of Kyasanur forest disease in Western Ghats of Kerala, South India.

Tick borne zoonotic diseases are one of the major emerging threats to live stock and public health in India, especially in Western Ghats of south India. Since livestock and wild animals share habitats and grasslands, it is important to know the species composition of major tick parasitism on live stock as well as their geographical distribution for effective control of tick and tick borne diseases. This study provides basic knowledge that is necessary to initiate Kyasanur Forest Disease (KFD) prevention programs in these areas. Ticks were sampled from Wayanad districts of Kerala from domestic animals and identified morphologically. A total of 195 cattle searched, in which 168 (86.15%) cattle were infested with ticks and a total of 3633 ticks comprising three genera and seven species were collected, Rhipicephalus microplus (52.71%) was prevalent species followed by Haemaphysalis bispinosa (16.9%), Rhipicephalus decoloratus (15.77%), Haemaphysalis turturis (11.42%), Rhipicephalus sanguineus (1.32%), Amblyomma integrum (1.15%) and Haemaphysalis spinigera (0.71%) were identified based on their morphological characters. As R. microplus was the prevalent species, the risk of transmission of babesiosis and anaplasmosis to cattle increases and the presence of Haemaphysalis sp. point out the risk of KFD in among the tribal colony people and it can be reduced by applying with acaricides on domestic animals.

Kinetics of viral RNA, immunoglobulin-M & G antibodies in Kyasanur forest disease

Background & objectives:Kyasanur forest disease (KFD) is an infectious disease discovered in Karnataka State of India in 1957; since then, the State has been known to be enzootic for KFD. In the last few years, its presence was observed in the adjoining five States of the Western Ghats of India. The present study was conducted to understand the kinetics of viral RNA, immunoglobulin M (IgM) and IgG antibody in KFD-infected humans for developing a diagnostic algorithm for KFD.Methods:A prospective follow up study was performed among KFD patients in Sindhudurg district of Maharashtra State, India. A total of 1046 suspected patients were tested, and 72 KFD patients were enrolled and followed for 17 months (January 2016 to May 2017). Serum samples of KFD patients were screened for viral RNA, and IgM and IgG antibodies.Results:KFD viral positivity was observed from 1st to 18th post-onset day (POD). Positivity of anti-KFD virus (KFDV) IgM antibodies was detected from 4th till 122nd POD and anti-KFDV IgG antibodies detected from 5th till 474th POD. A prediction probability was determined from statistical analysis using the generalized additive model in R-software to support the laboratory findings regarding viral kinetics.Interpretation & conclusions:This study demonstrated the presence of KFD viral RNA till 18th POD, IgM antibodies till 122nd POD and IgG till the last sample collected. Based on our study an algorithm was recommended for accurate laboratory diagnosis of KFDV infection. A sample collected between 1 and 3 POD can be tested using KFDV real-time reverse transcriptase polymerase chain reaction (RT-PCR); between 4 and 24 POD, the combination of real-time RT-PCR and anti-KFDV IgM enzyme-linked immunosorbent assay (ELISA) tests can be used; between POD 25 and 132, anti-KFDV IgM and IgG ELISA are recommended.

Kyasanur Forest disease virus infection activates human vascular endothelial cells and monocyte-derived dendritic cells

Kyasanur Forest disease virus (KFDV) is a highly pathogenic tick-borne flavivirus enzootic to India. In humans, KFDV causes a severe febrile disease. In some infected individuals, hemorrhagic manifestations, such as bleeding from the nose and gums and gastrointestinal bleeding with hematemesis and/or blood in the stool, have been reported. However, the mechanisms underlying these hemorrhagic complications remain unknown, and there is no information about the specific target cells for KFDV. We investigated the interaction of KFDV with vascular endothelial cells (ECs) and monocyte-derived dendritic cells (moDCs), which are key targets for several other hemorrhagic viruses. Here, we report that ECs are permissive to KFDV infection, which leads to their activation, as demonstrated by the upregulation of E-selectin, intercellular adhesion molecule 1, and vascular cell adhesion molecule 1 at the mRNA and protein levels. Increased expression of these adhesive molecules correlated with increased leukocyte adhesion. Infected ECs upregulated the expression of interleukin (IL)-6 but not IL-8. Additionally, moDCs were permissive to KFDV infection, leading to increased release of IL-6 and tumor necrosis factor-α. Supernatants from KFDV-infected moDCs caused EC activation, as measured by leukocyte adhesion. The results indicate that ECs and moDCs can be targets for KFDV and that both direct and indirect mechanisms can contribute to EC activation.

Kyasanur Forest Disease Classification Framework Using Novel Extremal Optimization Tuned Neural Network in Fog Computing Environment.

Kyasanur Forest Disease (KFD) is a life-threatening tick-borne viral infectious disease endemic to South Asia and has been taking so many lives every year in the past decade. But recently, this disease has been witnessed in other regions to a large extent and can become an epidemic very soon. In this paper, a new fog computing based e-Healthcare framework has been proposed to monitor the KFD infected patients in an early phase of infection and control the disease outbreak. For ensuring high prediction rate, a novel Extremal Optimization tuned Neural Network (EO-NN) classification algorithm has been developed using hybridization of the extremal optimization with the feed-forward neural network. Additionally, a location based alert system has also been suggested to provide the global positioning system (GPS)-based location information of each KFD infected user and the risk-prone zones as early as possible to prevent the outbreak. Furthermore, a comparative study of proposed EO-NN with state of art classification algorithms has been carried out and it can be concluded that EO-NN outperforms others with an average accuracy of 91.56%, a sensitivity of 91.53% and a specificity of 97.13% respectively in classification and accurate identification of risk-prone areas.

Kyasanur forest disease: a rare viral hemorrhagic disease in India

Kyasanur forest disease (KFD) is a rare hemorrhagic disease in India and isolated in monkeys in the Kyasanur Forest of the Shimoga district, Karnataka State in India in 1957. KFD is a zoonotic disease and endemic in southern part of India. KFD Virus commonly infects the black faced langur monkey (Semnopithecus entellus). No evidence for human-to-human transmission. Large domestic animals (cows, goats, sheep) that become infected are thought be important only for sustaining tick population. When monkeys come in contact with the infected ticks, they get infected, amplify and disseminate the infection creating hot spots of infection. The people who pass through the forest are bitten by the infected nymphs of H. spinigera, which are highly anthropophilic. Local villagers staying in and around the forest area frequently visit the forest for collection of fire woods, grass and get infected through tick bites. The incubation period is 3-8 days and patients presented with following symptoms like chills, frontal headache, bodyache, and high fever for 5-12 days. There were 466 human cases during initial outbreak and 181 more the following year and has caused epidemic outbreaks of haemorrhagic fever affecting 400 to 1000 people per year since then, with mortality rate of 4 and 15%. In 2012, 9 persons were found positive for KFD, in Theerthahlli taluk of district Karnataka. There is no specific treatment for KFD but a timely supportive therapy reduces the mortality in human being.

Comparative genome analysis of Alkhumra hemorrhagic fever virus with Kyasanur forest disease and tick-borne encephalitis viruses by the in silico approach

ABSTRACTAlkhumra hemorrhagic fever virus (AHFV), a relatively new member of the Flaviviruses, was discovered in Saudi Arabia 23 years ago. AHFV is classified in the tick-borne encephalitis virus serocomplex, along with the Kyasanur forest disease virus (KFDV) and tick-borne encephalitis virus (TBEV). Currently, very little is known about the pathologies of AHFV. In this study, using the available genome information of AHFV, KFDV and TBEV, we have predicted and compared the following aspects of these viruses: evolution, nucleotide and protein compositions, recombination, codon frequency, substitution rate, N- and O-glycosylation sites, signal peptide and cleavage site, transmembrane region, secondary structure of 5’ and 3’ UTRs and RNA-RNA interactions. Additionally, we have modeled the 3D protease and RNA-dependent RNA polymerase structures for AHFV, KFDV and TBEV. Recombination analysis showed no evidence of recombination in the AHFV genome with that of either KFDV or TBEV, although single break point analysis showed that nucleotide position 7399 (in the NS4B) is a breakpoint location. AHFV, KFDV and TBEV are very similar in terms of codon frequency, the number of transmembrane regions, properties of the polyprotein, RNA-RNA interaction sequences, NS3 protease and NS5 polymerase structures and 5’ UTR structure. Using genome sequences, we showed the similarities between these closely- related viruses on several different areas.

Epidemiology, Pathogenesis, and Control of a Tick-Borne Disease- Kyasanur Forest Disease: Current Status and Future Directions.

In South Asia, Haemaphysalis spinigera tick transmits Kyasanur Forest Disease Virus (KFDV), a flavivirus that causes severe hemorrhagic fever with neurological manifestations such as mental disturbances, severe headache, tremors, and vision deficits in infected human beings with a fatality rate of 3–10%. The disease was first reported in March 1957 from Kyasanur forest of Karnataka (India) from sick and dying monkeys. Since then, between 400 and 500 humans cases per year have been recorded; monkeys and small mammals are common hosts of this virus. KFDV can cause epizootics with high fatality in primates and is a level-4 virus according to the international biosafety rules. The density of tick vectors in a given year correlates with the incidence of human disease. The virus is a positive strand RNA virus and its genome was discovered to code for one polyprotein that is cleaved post-translationally into 3 structural proteins (Capsid protein, Envelope Glycoprotein M and Envelope Glycoprotein E) and 7 non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5). KFDV has a high degree of sequence homology with most members of the TBEV serocomplex. Alkhurma virus is a KFDV variant sharing a sequence similarity of 97%. KFDV is classified as a NIAID Category C priority pathogen due to its extreme pathogenicity and lack of US FDA approved vaccines and therapeutics; also, the infectious dose is currently unknown for KFD. In India, formalin-inactivated KFDV vaccine produced in chick embryo fibroblast is being used. Nevertheless, further efforts are required to enhance its long-term efficacy. KFDV remains an understudied virus and there remains a lack of insight into its pathogenesis; moreover, specific treatment to the disease is not available to date. Environmental and climatic factors involved in disseminating Kyasanur Forest Disease are required to be fully explored. There should be a mapping of endemic areas and cross-border veterinary surveillance needs to be developed in high-risk regions. The involvement of both animal and health sector is pivotal for circumscribing the spread of this disease to new areas.

Prevalence and spatial distribution of Ixodid tick populations in the forest fringes of Western Ghats reported with human cases of Kyasanur forest disease and monkey deaths in South India.

Kyasanur forest disease (KFD) is a major tick-borne viral haemorrhagic fever caused by KFD virus (KFDV) (Flaviviridae). The disease was reported to beconfined to five districts of Karnataka state India until 2011. During 2012-2016, emergence of KFD has been reported in newer areas of Karnataka and adjoining states. Therefore, survey of tick vectors was carried out in these new areas of Karnataka and adjoining states reported with monkey deaths and human cases of KFD. In all selected sites, ticks from the forest floor were collected by lint clothes using flagging method. Tick samples were tested for KFDV nucleic acid by real-time RT-PCR. A total of 4772 ticks, comprising eight species of genus Haemaphysalis and one species each of genus Amblyomma, Ixodes and Rhipicephalus was collected. Haemaphysalis spinigera, the principal vector of KFDV was the predominant tick species (59.5%) collected followed by H. turturis (8.6%). The abundance of H. spinigera ranged from 9.2 to 33.9 per man-hour in the six districts surveyed. Of 214 (4418 tick samples) pools screened by real-time RT-PCR, two pools of H. spinigera were positive for KFDV. High abundance of Haemaphysalis vectors in the six districts indicated that the districts are receptive for KFD outbreaks. KFDV was detected in the tick vectors in the new foci of the KFD. Data on tick distribution will be useful in creating KFD risk map for strengthening the ongoing preventive measures such as vaccination and supply of insect repellents to the high risk groups and intensive health education.