Prevalence of ixodid ticks on goats and risk factors for tick-borne diseases in humans in the Kyasanur forest disease endemic area of Kerala, India.

In India, tick-borne diseases are prevalent in many states due to the presence of tick vectors. However, information on disease-causing ticks from domestic animals and the associated risk factors for residents living in the disease-endemic area is lacking. Therefore, we conducted this study to identify ixodid ticks in goats and human risk factors in three villages of the Wayanad district of Kerala. We examined 202 goats and collected 741 ticks, of which 69.8% were ticks belonging to the genus Haemaphysalis. The maximum number of ticks was collected from Thirunelli (81.3%), followed by Noolpuzha (76.27%) and Pulpally (45.6%). Overall, H. bispinosa Neumann, 1897 (54.6%), was the most common species, followed by H. turturis Nuttall and Warburton, 1915 (38.0%), H. spinigera Neumann, 1897 (5.4%), and H. intermedia Warburton and Nuttall, 1909 (1.8%). We included 428 participants (men and women) in this study. The average age of the respondents was 43 years. We found significant associations between accessing the forest for cattle grazing and other activities and tick-borne diseases (χ2 = 9.5, p = 0.002), between workers who were bitten by ticks and tick-borne diseases (χ2 = 3.8, p = 0.05), and between number of tick bites per day > 6 and tick-borne diseases (χ2 = 12.1, p = 0.001). The high frequency of Haemaphysalis spp. found in goats highlighted the risk of tick exposure and tick-borne diseases, such as Kyasanur forest disease in humans, and the need for the development and implementation of effective measures to control ticks.

Preliminary survey on the distribution of Ixodid ticks in domestic ruminants and vegetation of Pathanamthitta district, Kerala, South India.

BACKGROUND OBJECTIVES: Tick borne diseases (TBD) are becoming a major public and animal health problem in the Kerala. Recently, during 2021 - 2022, a new focus of tick nuisance and associated fever has been reported in some villages of Pathanamthitta district. METHODS: The study on the diversity of tick fauna in Southern Kerala is limited. Therefore, a preliminary survey was carried out for the first time in this focus for implementation of future tick borne pathogen detection and control measures. This research may provide a proper understanding of tick density and acarological risk by tick ecology through surveillance and identification. A cross sectional study was conducted during the summer season of 2021 and 2022 in the tick bite infected area - Naduvathumoozhy, Vayakkara, Malayalappuzha and Pallikuzhi. RESULTS: Ticks were manually collected from ruminants and by dragging method from vegetation. A total of 727 ticks of 8 different species were collected from the genus Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus. The most prevalent species were H. bispinosa and H.turturis, at 38.7% and 29.1%, respectively. Ticks were sampled from 197 animals with the proportion of infestation being 73.60%. It was highest in goats (85.9%), followed by buffalo (73.6%) and cow (65.4%). INTERPRETATION CONCLUSION: The study concludes that, despite the absence of any TBD outbreaks, the Pathanamthitta district has a high diversity of tick fauna and a high rate of tick infestation in domestic ruminants, especially in goats. Hence active tick surveillance is necessary in order to prevent TBD outbreaks in future; the study also emphasizes the importance of performing tick surveillance in both KFD endemic and non-endemic regions.

Influence of environmental factors on tick diversity and abundance in different animal resting habitats in forest areas of the south Western Ghats.

Most tick-borne disease causing pathogens originate in wildlife and are zoonotic in nature. A key to protecting human and animal health is to understand the biology and ecology of tick establishment. The tick distribution in wild animal habitats has been attributed to multiple environmental factors, and the studies on this topic are limited. Therefore, the objective of the study is to understand the influence of environmental factors on tick diversity and abundance in wild animal resting habitats. The study was carried out in 21 different animal resting habitats in the forest areas of Wayanad district, and they were divided into three groups based on the presence or absence of selected environmental parameters. A total of 10,849 ticks with 12 species belonging to five genera were collected. Regardless of the type of habitats, Haemaphysalis spinigera (59.52%) and Haemaphysalis turturis (33.20%) were the dominant species. Tick abundance showed greater variability between types of habitats ranging from 1.23 to 28.5. The greatest diversity and abundance were found in the group one. The group 3 had greater diversity and less abundance than the group 2. Both Simpson's diversity index and Shannon's diversity index were high for groups 2. Substantial variation in diversity and abundance of ticks occurred in different groups based on different environmental factors. The dominance of ticks of the genus Haemaphysalis a primary vector of Kyasanur Forest Disease highlights the need to carry out various control strategies to reduce the tick population.

The species distribution of ticks & the prevalence of Kyasanur forest disease virus in questing nymphal ticks from Western Ghats of Kerala, South India.

Background & objectives: Kyasanur forest disease (KFD) is a zoonotic tick-borne disease across the Western Ghats of India. With the discovery of a cluster of human KFD cases in the Wayanad district of Kerala, the present study was focused on detecting KFD virus (KFDV) in tick populations. To manage this disease, it is necessary to understand the diversity of the tick species and factors influencing the distribution, abundance and prevalence of infected ticks in Wayanad district. Methods: Surveys were conducted from November 2016 to May 2018 in four forest ranges of Wayanad district. Ticks were collected by the dragging method and were identified to species level and assayed for virus detection using real-time polymerase chain reaction. Results: A total of 25,169 ticks were collected from 64 sites. Of the identified species, Haemaphysalis spinigera was the most abundant (56.64%), followed by H. turturis 9047 (35.94%), H. bispinosa 999 (3.96%), Amblyomma integrum 691 (2.74%), H. kyasanurensis (0.55%), Rhipicephalus sanguineus (0.08%), Hyalomma marginatum (0.02%), H. cuspidata (0.01%), R.microplus (0.01%) and Dermacentor auratus (0.003%). The nymphal stage was predominant from December to February having peak activity in January. A total of 572 pools were screened for the presence of KFDV, of which 21 pools were positive. The infection rates in H. spinigera and H. turturis tick were 2.62 and 1.04 per cent, respectively. Interpretation & conclusions: The circulation of KFDV was detected and its correlation with the prevalence in ticks near the fragmented forest and teak plantation areas of Wayanad district. Residents and visitors of these regions may become vulnerable to tick bites and to an increased risk of KFD as the distribution of established, infected tick populations continues to expand.

Ecology of breeding habitats of mosquito population and screening for virus of Japanese encephalitis and West Nile in the coastal area of Kerala, India.

BACKGROUND & OBJECTIVES: Japanese encephalitis (JE) and West Nile virus (WNV) are two mosquito-borne diseases of medical and veterinary importance. Climate impacts in certain ecosystems are better understood; however, coastal brackish water ecosystems and their role in vector borne viral diseases have not been well studied. Hence, the aim of this study is to evaluate the distribution, spatial pattern as well as the screening of these mosquitoes for JE and WN virus in coastal area of Alappuzha district, Kerala, India. METHODS: Immature mosquitoes were collected using dipper methods along the coastal wetlands areas. Adult mosquitoes were collected in four sampling sites with light trap filled with dry ice, operating overnight. The collected mosquitoes were identified by species, using the taxonomic keys. Mosquitoes were pooled for virus detection. Water samples were collected using standard methods. RESULTS: The total quantity of rainfall and salinity varied from zero to 365.2 mm and from 1.5 to 28 ppt respectively. A total of 10,695 adult mosquitoes and 38,083 immatures revealed the presence of five genus and 23 species. The most predominant species was Culex tritaeniorhynchus. Immature collections Cx. sitiens was the only one species collected during the summer season and in the monsoon season the pond was replaced by fresh water mosquitoes such as Cx. tritaeniorhynchus and Cx. gelidus. A total of 186 pools were screened for JEV and WNV. However, none of the pools were found as positive for the virus. INTERPRETATION & CONCLUSION: The major vector of JEV Cx. tritaeniorhynchus and Cx. gelidus have adapted to immature development in coastal brackish water habitats. The public health authorities need to recognize thepotential impact on human health of brackish water-adapted mosquito vectors that weretraditionally considered to be freshwater species, and take appropriate surveillance and control measures.

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.