SESSION TITLE: Infectious Disease Global Case Reports
SESSION TYPE: Global Case Report
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: In elephants, tuberculosis is a spillover disease resulting mostly from human cohabitation and most cases are caused by the human strains of Mycobacterium tuberculosis. Captive elephants in southern India are kept in hands-on contact with mahouts (elephant keepers) as well as public. In the field settings in southern India where there is a significant prevalence of tuberculosis in humans, human-to-elephant and elephant-to-human transmission of tuberculosis presents disease risks to both the in-contact species. A collaborative research involving medical physicians, veterinarians and molecular biologists is studying the transmission dynamics of tuberculosis infection among captive elephants and mahouts. Systematic tuberculosis screening of the nearly 1000 captive elephants and 5000 mahouts in southern India is underway. Screening of mahouts is done by clinical examination and tuberculin skin testing, followed by chest X-ray and sputum collection as required. Screening of elephants is done with the USDA licensed rapid serum tests Elephant TB STAT-PAK® and DPP Vet Assay® (Chembio Diagnostics Inc. Medford NY), followed by trunk wash culture for isolation and identification of mycobacteria.
CASE PRESENTATION: We identified two probable cases of cross-species transmission of M. tuberculosis between mahouts and captive elephants. First is case of human-to-elephant and second is a case of elephant-to-human transmission of M. tuberculosis. Case#1: A female elephant tested positive on Elephant TB STAT-PAK® and showed clinical symptoms of tuberculosis. There has been hand-on interaction between this elephant and its mahout for the past 25 years. The mahout was found to be suffering from active tuberculosis and tested positive on tuberculin skin test and showed shadows in his chest X-ray. M. tuberculosis culture isolate was obtained from one of the three sputum samples collected from the mahout and was sensitive to first line anti-tuberculous drugs. Case#2: Another male elephant tested positive on Elephant TB STAT-PAK® and also showed symptoms of tuberculosis. The mahout associated with this elephant had a cutaneous nodule on the palm of right hand. This nodule, which was later operated and removed, was confirmed by histopathology as a case of tuberculous granuloma. Further inquiry revealed that this mahout previously suffered injuries to his hand while trying to control the elephant and the wound was contaminated with discharges from the elephant’s trunk. The mahout tested positive on tuberculin skin test, but chest X-ray did not reveal any lesion suggestive of tuberculosis. Trunk wash samples from both elephants are collected for the isolation and identification of mycobacteria.
DISCUSSION: During the life span of nearly 50 years a captive elephant lives in close contact with humans. Also as a wild animal in captivity surviving in unnatural surroundings that add stress, the captive elephants present a unique animal model for an observational study to assess the disease risks of interspecies transmission of tuberculosis. This study intends to identify modifiable risk factors, if any, for effective policy intervention for prevention and control.
CONCLUSIONS: M. tuberculosis infection spillover and the risk of zoonosis from infected elephants is a well researched subject in the United States. In developing countries, mainly due to ineffective surveillance, such cases are rarely reported and documented. This poster presents a pictorial depiction of the different aspects of these two probable cases of cross-species transmission of M. tuberculosis.
Reference #1: Murphree, R., Warkentin, J. V., Dunn, J. R., Schaffner, W., & Jones, T. F. (2011). Elephant-to-human transmission of tuberculosis, 2009. Emerging Infectious Diseases, 17(3), 366-371.
Reference #2: Mikota, S. K., & Maslow, J. N. (2011). Tuberculosis at the human-animal interface: an emerging disease of elephants. Tuberculosis, 91(3), 208-211.
Reference #3: Greenwald, R., Lyashchenko, O., Esfandiari, J., Miller, M., Mikota, S., Olsen, J. H., . . . Moller, T. (2009). Highly accurate antibody assays for early and rapid detection of tuberculosis in African and Asian elephants. Clinical and Vaccine Immunology, 16(5), 605.
DISCLOSURE: The following authors have nothing to disclose: Venugopal Kummannoor Parameswaran Pillai, David Abraham
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