Tuberculosis and Herpes- an emerging threat to Elephant population

Tuberculosis and Herpes- an emerging threat to Elephant population

T.P.Sethumadhavan
Introduction
Elephant population in the world is facing serious threats. These include habitat loss, human elephant conflict and the emerging diseases. Two emerging diseases, Tuberculosis and Endotheliotropic herpes viral infection are causing heavy mortality among elephants. This paper explains the need for developing better epidemiological, immunological and diagnostic methods, which will hasten the disease control measures in a sustainable manner.
Tuberculosis
Tuberculosis has recently become a significant health problem for captive Asian elephants. Elephant care international estimates that 12 percent elephants are infected. Over the years as habitat diminishes and interaction with human increases Asian Elephant population has decreased dramatically. Although TB prevalence levels among elephants are not exceptionally high at the present time, animals are experiencing increased contacts with humans and cattle, natural reservoirs from Mycobacterium tuberculosis and M.bovis respectively. Thus the possibility of an epidemic exists and reciprocal transmission between humans and elephants could have devastating consequences.
A comprehensive epidemiological assessment of TB among captive Asian elephants is needed. It should expand in three complementary areas like immunological tests on individual animals to document infection status, seroprevalence studies, behavioral studies to infer exposure history and molecular analysis of bacterial DNA from trunk washes for species and strain identification.
The host immune response plays a vital role in the pathogenesis of infectious disease. An appropriate immune response results in clearance of offending pathogens, whereas an inappropriate response can facilitate disease. Tuberculosis is an example of a disease associated with an aberrant or inadequate immune response. Because information on elephant immune function is lacking, development of new tools that can facilitate assessment of immune response in elephants is the first step towards understanding tuberculosis pathogenesis in elephants. This tool will be vital towards gaining a general understanding of elephant immune responses to infectious disease. Information regarding pathogenesis, quantification of cytokine/ inflammatory mediator gene expression in peripheral blood samples can offer new diagnostic and treatment monitoring opportunities which may ultimately impact optimal management of tuberculosis in elephants. Recent findings revealed that a variety of side effects occur in elephants, which are being treated with anti tuberculosis drugs.

Elephant endotheliotropic herpes virus-

Elephant endotheliotropic herpes virus (EEHC, genus-Probosci virus) is a serious threat to all populations of Asian elephants and the diagnosis, prevention and treatment of EEHV is a high priority for the international elephant community. EEHV infects the micro vascular endothelial cells of the heart, liver and tongue. Viral induced endothelial injury leads to multiple areas of hemorrhage with death attributed to cardiac or multi organ failure. A substantial proportion of reproductive failures and young elephant deaths have been attributed to EEHV, continually impeding efforts to maintain a self-sustaining captive Asian elephant population. Multiple elephant mortalities attributed to EEHV have been reported in Asia since 1995. Recent findings revealed that approximately 10 percent of the North American Asian elephant population has been found to be seropositive for EEHV. Information regarding pathogenesis, epidemiology, seroprevalence and treatment will make significant impact on elephant welfare in the country.