Case report of hook worm Grammocephalus hybridatus and stomach bot Cobboldia elephantis infections in a free-ranging Asian Elephant Elephas maximus in Tamil Nadu, India

Abstract

Elephants in the wild are susceptible to many gastrointestinal parasites. In the present study, necropsy was conducted on a free-ranging Asian Elephant Elephas maximus female aged about 15 years which died at Coimbatore forest range, Tamil Nadu state, India. The necropsy revealed that the liver was infected with round worms and the stomach was heavily infested with dipteran larvae. These round worms and larvae were collected and processed by dehydrating in ascending grades of alcohol and then cleared in carbolic acid. The cleared samples were mounted and examined under light microscopy for species identification. Faecal samples collected from the rectum were analysed by sedimentation for the presence of helminth eggs. On microscopic examination, the head end of the round worms showed a buccal capsule which possessed a pair of semilunar ventral cutting plates. Male worms showed well-developed bursa at the posterior end. The anterior end of the dipteran larvae showed two powerful oral hooks with cephalopharyngeal skeleton. Anterior spiracle appeared as a short club-shaped tube with 12 lobes. The abdominal segments of the larvae had a row of belt-like triangular spines. The posterior spiracles of the larvae had three longitudinal parallel slits in each spiracle with closed peritreme. Based on the above morphological characters, the round worms and larvae were identified as Grammocephalus hybridatus and Cobboldia elephantis, respectively.  Strongyle eggs were identified in the faecal sample based on the morphology of thin shell and segmented yolk. This appears to be the first report of G. hybridatus infection in a free-ranging elephant in Tamil Nadu state, India.