Ticks as a potential vector for spotted fever group Rickettsiae (SFGR): An epidemiological study from Wayanad district, South India

The Microbe Pub Date : 2024-12-16 DOI:10.1016/j.microb.2024.100225

M. Swathy Viswanath , Rouchelle Charmaine Tellis , Vipin Viswanath , Sohanlal Thiruvoth

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Abstract

Ticks are the known vectors of Spotted Fever Group Rickettsia (SFGR), a pathogen responsible for several tick-borne diseases. Wayanad, a hilly district in Kerala, India, has reported recurring cases of these diseases, prompting this epidemiological study. The study was conducted from October 2022 to December 2023, and aimed to find the geographical distribution of ticks in forest-adjacent areas and evaluate their role as potential SFGR vectors. A total of 520 ticks were collected from animals (Cows, Buffaloes, Goats and Dogs) in 23 locations in Wayanad district, with Haemaphysalis bispinosa emerging as the most abundant species, accounting for 79.2 % of the total ticks collected. Haemaphysalis spinigera and Haemaphysalis turturis represented 18.2 % and 2.3 % of the ticks, respectively. Using nested PCR to target the gltA and ompA genes, SFGR-DNA was detected exclusively in H. bispinosa pools. In total, 52.17 % of the sampled areas contained ticks positive for SFGR. Of the 516 ticks screened, 408 ticks from 40 pools of H. bispinosa were found positive for SFGR. The Minimum Infection Rate (MIR) was highest in Zone-1 (10.7 %), followed by Zone-2 (9.69 %) and Zone-3 (9.52 %). The current study is the first of its kind to report the presence of SFGR in South India which has significant public health concerns as it is a neglected tropical disease. Molecular characterization and sequencing are further recommended along with continuous surveillance of tick vectors and the implementation of preventive strategies in this region.