Cobboldia elephantis (Cobbold, 1866) larval infestation in an Indian elephant (Elephas maximus)

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

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.

First record and analysis of the COI gene of Cobboldia elephantis obtained from a captive Asian elephant from Myanmar

The stomach bot fly species in Asian elephants has long been known as Cobboldia elephantis. However, there is no genetic information available for this species to date. Here, we report that a third-instar fly larva was excreted from a captive Asian elephant four months after export from an elephant camp in Myanmar to a zoological garden in Japan. Morphological characteristics of the larva were coincident with published descriptions of C. elephantis. The mitochondrial cytochrome c oxidase subunit I (COI) gene was amplified from the larva by PCR using primers modified from those designed for DNA barcoding of insects and amphibians. The COI gene of C. elephantis showed 76.6 % and 83.6 % identity at the nucleotide and amino acid levels, respectively, to that of C. loxodontis, the stomach bot fly species in African elephants. Phylogenetic analysis of the COI genes of several stomach bot fly species revealed that the two Cobboldia species formed a clade separate from the stomach bot fly species found in rhinoceros and equids.

Wound and gastric myiasis due to Chrysomyia bezziana and Cobbaldia elephantis and its pathological lesions in wild elephants in the Nilgiris hills of Tamil Nadu

Thirty-five years old female and 12 years old male wild elephant were found dead at Seviyodu and Cherangode of Cherambadi range at Nilgiris district, Tamil Nadu state. On post mortem examination, maggots were recovered from palate of oral cavity and gastric mucosa of the stomach and identified as Chrysomyia bezziana and Cobbaldia elephantis, respectively. Histopathology of oral tissue specimen revealed myonecrosis of soft palate due to myiasis and cross section of encysted larvae surrounded by fibrous capsule and inflammatory cells. This study reports the mixed infection of wound and gastric myiasis due to C. bezziana and C. elephantis and its histopathological lesions in wild elephants.