Pathological and molecular studies on elephant endotheliotropic herpesvirus haemorrhagic disease among captive and free-range Asian elephants in India.

In the present research pathology and molecular diagnosis of elephant endotheliotropic herpes virus-haemorrhagic disease (EEHV-HD) among Asian elephants was studied. Out of 76 cases, 20 were positive for EEHV infection in PANPOL and POL1 based semi-nested PCR. Out of 20 samples, 10 samples were fatal cases of EEHV-HD while 10 were of either subclinical or latent infection. Acute onset haemorrhagic disease with EEHV-HD had anorexia, facial and neck swelling, cyanotic buccal mucosa and tongue, nasal and ocular discharge, and colic. The hallmark of gross finding in all cases were severe haemorrhagic lesions in the internal organs viz. cyanosis of tongue with multifocal petechial haemorrhages, diffuse epicardial and endocardial haemorrhages, swollen liver (rounded edges) with parenchymal haemorrhages, serosal and mucosal haemorrhages in gastrointestinal tract, congested kidneys with corticomedullary haemorrhages, highly congested meninges, and brain capillaries with haemorrhages. Microscopic findings in all the cases had severe vascular changes in the visceral organs. Microthrombi was present in the vasculature of tongue, heart, lung, liver, kidney, and brain. The endothelial lining of most of the blood vessels were swollen with apoptotic changes. Amphophilic to basophilic intranuclear inclusion bodies were observed in the endothelial cells. Immunostaining using anti-EEHV DNAPOL hyperimmune sera revealed intense positive signals in the endothelium of blood vessels and their walls. Quantification of viral load in necropsy tissue samples revealed highest in the heart (7.4 × 106/µg of sample) and least in the brain (9 × 103/µg of sample). The PCR amplicons from EEHV1 specific genes (POL1(U38) and TER were subjected to partial genome sequencing which had 99.9% similarity with the EEHV1A subtype. It was concluded that Asian elephants in India are latently infected for EEHV1 and in all the fatal EEHV-HD cases, EEHV1A subtype was the causative agent with characteristic pathomorphological changes in visceral organs.

A study on clinical diagnosis of tuberculosis in free ranging and captive wild animals of India.

Background: Tuberculosis (TB) is a disease of paramount importance at the wildlife-livestock-human interface. Aims: To study the occurrence and Mycobacterium (M) species involved in the TB of free-ranging and captive wild animals in various Indian states. Methods: A total of 396 clinical samples from 207 different wild animal species from various Indian national parks, zoological gardens, etc., were analyzed by lateral flow assay (LFA), Ziehl-Neelsen (ZN) staining, and PCR. Clinical samples include blood (n=156), faecal swabs (n=103), serum (n=73), and nasal swabs or trunk wash fluids (n=64). Results: Clinical signs of TB were absent in 202 animals, although 21 wild animals were seropositive for pathogenic Mycobacterium antigens by LFA. Clinical signs like progressive weight loss, and respiratory distress were exhibited by 4 sloth bears (Melursus ursinus) and an elephant (Elephas maximus), which were also found positive for LFA, PCR, and ZN staining. ZN staining showed positivity for acid-fast bacilli (AFB) in 9 (8.74%) faecal and 9 (14.06%) nasal swabs or trunk wash fluids of sloth bears (7 samples) and elephants (2 samples). M. tuberculosis was detected in 7 sloth bears and 2 elephants, whereas M. bovis was found in a spotted deer (Axis axis) by species-specific PCR. Conclusion: The circulation of TB organisms in wild animals warrants a strict surveillance programme to identify the carrier status of these animals so that effective TB control strategies can be formulated.