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.
KeywordsSpatial distribution Haemaphysalis spinigera Tick abundance KFD vector Kyasarnur Forest Disease
Authors acknowledge their sincere gratitude to all the state and district Government health officials of Wayanad in Kerala, Nilgiris in Tamilnadu, Shimoga in Karnataka, North Goa in Goa and Sindhudurg in Maharashtra for their immense support in executing this study. We would also like to extend our gratitude for all the AFI Project Administrators, Site managers, Specialists, Research assistants, technicians and field support staffs for their support in this study.
Designed the study: NBN, AJ; performed the experiment: NBN, AJ, HKH, PP, ADH, SP, MS, NK, YB, SD and AMA; GIS and data analysis: HM; wrote the paper: NBN, PP and SP; Reviewed: GA and all work supervised: GA and JA. All authors have read and approve the final version of the manuscript.
This work was partially funded from AFI project under the Cooperative Agreement, Grant no U01GH001051, awarded to GA, Manipal Academy of Higher Education by Centers for Disease Control and Prevention (CDC), Atlanta, USA.
Compliance with ethical standards
Conflict of interest
The authors declares that they have no conflict of interest.
The views expressed in this manuscript are those of the authors and do not necessarily represent the official position of the Manipal Academy of Higher Education or the US Centers for Disease Control and Prevention.
- Banerjee K, Bhat HR (1977) Correlation between the number of persons suffering from Kyasanur Forest Disease and the intensity of infection in the tick population. Indian J Med Res 66:175–179Google Scholar
- Bhat HR, Naik SV (1978) Transmission of Kyasanur Forest Disease virus by Haemaphysalis wellingtoni Nuttall and Warburton, 1907 (Acarina: Ixodidae). Indian J Med Res 67:697–703Google Scholar
- Bhat HR, Sreenivasan MA, Goverdhan MK, Naik SV (1975) Transmission of Kyasanur Forest Disease virus by Haemaphysalis kyasanurensis trapido, Hoogstraal and Rajagopalan, 1964 (Acarina: Ixodidae). Indian J Med Res 63:879–887Google Scholar
- Fish DaCH (1999) Methods used for creating a national Lymedisease risk map vol 48. Centers for Disease Control and Prevention, AtlantaGoogle Scholar
- Geevarghese G, Mishra AC (2011) 2-Structurally primitive haemaphysalines. In: Haemaphysalis Ticks of India. Elsevier, London, pp 21–226. https://doi.org/10.1016/B978-0-12-387811-3.00002-4 CrossRefGoogle Scholar
- Ghosh SN, Rajagopalan PK, Singh GK, Bhat HR (1975) Serological evidence of arbovirus activity in birds of KFD epizootic–epidemic area, Shimoga District, Karnataka, India. Indian J Med Res 63:1327–1334Google Scholar
- Gunawardene N et al (2007) A brief overview of the Western Ghats—Sri Lanka biodiversity hotspot vol 93Google Scholar
- Gurav YK et al (2018) Kyasanur Forest Disease prevalence in Western Ghats proven and confirmed by recent outbreak in Maharashtra, India, 2016 vector borne and zoonotic diseases 18:164–172. https://doi.org/10.1089/vbz.2017.2129
- Mourya DT, Yadav PD, Patil DY (2014) 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 3:8–21. https://doi.org/10.4103/2224-3151.206890 Google Scholar
- Pavri KM, Singh KR (1968) Kyasanur Forest Disease Virus infection in the frugivorous bat, Cynopterus sphinx. Indian J Med Res 56:1202–1204Google Scholar
- Rajagopalan PK, Paul SD, Sreenivasan MA (1969a) Involvement of Rattus blanfordi (rodentia: Muridae) in the natural cycle of Kyasanur Forest Disease virus. Indian J Med Res 57:999–1002Google Scholar
- Rajagopalan PK, Paul SD, Sreenivasan MA (1969b) Isolation of Kyasanur Forest Disease virus from the insectivorous bat, Rhinolophus rouxi and from Ornithodoros ticks. Indian J Med Res 57:805–808Google Scholar
- Robbins DRG (2012) Tick-borne diseases: vector surveillance and control. Armed Forces Pest Management Board, Information Services Division, Silver springGoogle Scholar
- Sadanandane C, Gokhale MD, Elango A, Yadav P, Mourya DT, Jambulingam P (2018) 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. Exp Appl Acarol 75:135–142. https://doi.org/10.1007/s10493-018-0223-5 CrossRefGoogle Scholar
- Singh KR, Pavri KM, Anderson CR (1964) Transmission of Kyasanur Forest Disease virus by Haemaphysalis turturis, Haemaphysalis papuana kinneari, Haemaphysalis minuta. Indian J Med Res 52:566–573Google Scholar
- Sreenivasan MA, Rajagopalan PK, Bhat HR (1983) Spatial distribution of infected Haemaphysalis nymphs in the epizootic localities of Kyasanur Forest Disease. Indian J Med Res 78:531–536Google Scholar
- Trapido H, Rajagopalan PK, Work TH, Varma MG (1959) Kyasanur Forest Disease. VIII. Isolation of Kyasanur Forest Disease virus from naturally infected ticks of the genus Haemaphysalis. Indian J Med Res 47:133–138Google Scholar