Tuberculosis surveillance of elephants (Elephas maximus) in Nepal at the captive-wild interface

Authors: MIKOTA, SUSAN - Elephant Care International; GAIRHE, KAMAL - Department Of National Parks And Wildlife Conservation; GIRI, KAMAL - Tribhuvan University; HAMILTON, KARIN - University Of Minnesota; MILLER, MICHELE - Stellenbosch University; PAUDEL, SARAD - Hokkaido University; LYASHCHENKO, KONSTANTIN - Chembio Diagnostic Systems, Inc; LARSEN, R - Denver Zoological Gardens; PAYEUR, JANET - Animal And Plant Health Inspection Service (APHIS); Waters, Wade; GREENWALD, RENA - Chembio Diagnostic Systems, Inc; DUMONCEAUX, GENEVIEVE - Palm Beach Zoo; VINCENT, BARBARA - Elephant Care International; KAUFMAN, GRETCHEN - Washington State University

Submitted to: European Journal of Wildlife Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2014
Publication Date: 1/10/2015
Citation: Mikota, S.K., Gairhe, K., Giri, K., Hamilton, K., Miller, M., Paudel, S., Lyashchenko, K., Larsen, R.S., Payeur, J.B., Waters, W.R., Greenwald, R., Dumonceaux, G., Vincent, B., Kaufman, G. 2015. Tuberculosis surveillance of elephants (Elephas maximus) in Nepal at the captive-wild interface. European Journal of Wildlife Research. 61:221-229.

Interpretive Summary: Tuberculosis is common in elephants in zoos, circuses, and wildlife parks worldwide. This infection represents a serious risk to elephant handlers, exhibit visitors, and other animals; and threatens the sustainability of this species in the wild. Two methods are currently recognized to diagnose tuberculosis in elephants: trunk wash culture and a recently developed assay to detect antibodies to the infection. In the present study, a comprehensive screening of elephants (both government and private owned captive Asian elephants) in Nepal was performed using culture and serology. Findings indicate that the antibody-based test is a much more sensitive and reliable measure of the disease. From the results, elephants were assigned to risk groups to prioritize management activities and recommendations. These findings will be useful for wildlife authorities in Nepal to protect their captive elephants and the people coming into contact with these animals, and to safeguard tourism.

Technical Abstract: A comprehensive elephant tuberculosis (TB) survey using culture and four serological screening tests was conducted in Nepal. Private and government-owned male and female captive Asian elephants (Elephas maximus) were included in the study. The mean reported age was 38 years (range 5-60 years). A total of 289 samples from 120 elephants were collected for mycobacterial culture. Culture samples were processed at the National Tuberculosis Centre in Nepal (NTC) and the National Veterinary Services Laboratories (NVSL) in Ames, Iowa. Acid-fast organisms were observed in 11 and 21 samples processed at NTC and NVSL respectively, and non-tuberculous mycobacteria (NTMs) were isolated from six elephants. There were no isolations of M. tuberculosis or M. bovis. Blood samples were also collected from 115 of the elephants for serological testing using the Chembio ElephantTB STAT-PAK®, the Chembio MultiAntigen Print Immunoassay test, a multi-antigen ELISA, and an immunoblot assay. Results from culture and serological testing were highly variable and required careful interpretation to develop criteria for assessment of TB risk. Elephants were assigned to one of four disease risk groups (high, moderate, low, and undetermined) and management recommendations were made for each group to government authorities. Given the limitations of culture and inconclusive culture results, priority was placed on serological results when developing recommendations. This strategy was based on evidence for early predictive value of serological tests and the urgent need expressed by wildlife authorities in Nepal to protect their captive elephants, mitigate TB at the captive-wild interface, and safeguard tourism.