Understanding the seasonality of KFD, leptospirosis and scrub typhus transmission dynamics and risk to humans.

The forested regions of the Western Ghats have high biodiversity and complex ecological communities. We are investigating three zoonoses (diseases passed to humans from animals) where small mammals have an important role in the transmission cycle: Kyasanur Forest Disease (KFD), leptospirosis and scrub typhus. Human cases of these diseases have been reported from rural communities within the Western Ghats but we lack up to date knowledge about how the vectors and wildlife and domestic animal hosts for these diseases are distributed spatially within the fragmented habitats of the Western Ghats and how vector and host behaviour and abundance may change seasonally across the year within this landscape. 

Historically, evergreen, semi-evergreen and moist-deciduous forests were considered to be the highest risk habitats for KFD-infected ticks. However, our previous MonkeyFeverRisk project (https://www.monkeyfeverrisk.ceh.ac.uk/) suggests that the risk of spillover of Kyasanur Forest Disease from vectors and animals to people is highest in diverse agro-forestry landscapes that are created when moist evergreen forest is replaced with plantations and paddy cultivation. We also found that the risk of human exposure to infected ticks is not just restricted to forests but extends to forest edges, plantations, houses and gardens and involves other tick species as well as Haemophysalis spinigera. Within the Western Ghats, we lack understanding of spatial and temporal risk of leptospirosis and scrub typhus, and whether the seasonality of KFD transmission cycles has changed since the pioneering work of Dr Rajagopalan and others last century, which occurred prior to advanced climate warming and extensive habitat fragmentation in the region.
 

Approach

We aim to gather crucial empirical data on how disease, vector and host communities vary across habitats and through the annual seasonal cycle for sites known to have had relatively high case numbers of human infections of the three focal diseases. 

Tick samples‚Äč

Some of the tick species collected from wild animal and livestock hosts

We will undertake monthly sampling of the environment, vectors and wildlife and domestic animal hosts across habitat gradients, including around houses, within the agricultural matrix and forests. We will also evaluate how hosts, including humans, move seasonally within the forest landscape and how this is related to risk of acquiring vectors and disease.

Map showing study area transects, tick collecting and small mammals

Transects of traps through the agro-forest matrix will be used to sample small mammals and ticks. Sampling of water bodies, primates, dogs, livestock and birds will also take place monthly at each site

Outcomes and Impact

Better ecological understanding of spatial and temporal variation in disease risk from vectors and wildlife or domestic animal hosts, and how human behaviour maps onto this risk, is crucially important so that disease prevention and management strategies can be refined and developed. In conjunction with peer-reviewed publications, we aim to develop practical, structured guidance and policy on best disease management practices, and educational materials to increase knowledge of the risk posed by zoonotic diseases and how to prevent infections.