First report on coinfection of Fasciola jacksoni and Pseudodiscus collinsi in a free-ranging wild Asian elephant (Elephas maximus) in the Nilgiris, Tamil Nadu, India.

Abstract

In the present study 32 wild elephants across different forest ranges of the Nilgiris were screened for the presence of flukes during necropsy from December 2023 to November 2024, out of which only one elephant was found to be infected with flukes. The occurrence of Fasciola jacksoni flukes in liver and Pseudodiscus collinsi flukes in the caecum and colon of a Thirty five year old, free ranging male elephant (Elephas maximus) is reported. The infected elephant harboured a total of 22 numbers of F. jacksoni in the liver and 487 numbers of P. collinsi flukes in the caecum and colon. Morphologically F. jacksoni flukes were flat with ill-defined cephalic end armed with numerous minute dermal spines at both dorsal and ventral surfaces. Oral sucker was terminal and small whereas ventral sucker was large and well forward. Intestinal caeca were branched occupying nearly the whole extent of the body internally. Body of P. collinsi flukes were tapering anteriorly and rounded posteriorly with oral pouches and wavy intestinal caeca. The testes were deeply lobed, placed side by side and ovary was single, posterior to testes. The ventral sucker was subterminal. Liver of the elephant infected with F. jacksoni was enlarged, congested, hemorrhagic and bile tracts were filled with a dark yellowish deposition with numerous immature and mature flukes present inside the liver. Though numerous P. collinsi flukes were found in the caecum and colon, no pathological lesions were appreciable. The present observations on coinfection of Fasciola jacksoni and Pseudodiscus collinsi in a free ranging wild elephant seems to be the first report of its kind and will be important to map the status of fluke infections in wild elephants and to frame control strategies.