Tuberculosis in Rhinoceros: An Underrecognized Threat?

Abstract

Historical evidence of tuberculosis (TB) affecting primarily captive rhinoceroses dates back almost two centuries. Although the causative Mycobacterium tuberculosis complex (MTC) species has not been determined in many cases, especially for those that occurred before bacterial culture techniques were available, the spectrum of documented reports illustrates the importance of TB as cause of morbidity and mortality in different rhinoceros species across continents. In more recent years, sporadic suspected or confirmed cases of TB caused by Mycobacterium bovis (M. bovis) have been reported in semi-free or free-ranging rhinoceroses in South Africa. However, the true risk TB may pose to the health and conservation of rhinoceros populations in the country's large conservation areas where M. bovis is endemic, which is unknown. Underlying the current knowledge gap is the lack of diagnostic tools available to detect infection in living animals. As documented in other wildlife species, TB could establish itself in a rhinoceros population but remain unrecognized for decades with detrimental implications for wildlife conservation at large and should such animals be moved to uninfected areas or facilities. This paper reviews the current state of knowledge regarding TB in rhinoceros including critical gaps that need to be addressed to effectively assess the threat that this disease may present to rhinoceros.

Experimental Mycobacterium bovis infection in three white rhinoceroses (Ceratotherium simum): Susceptibility, clinical and anatomical pathology

“…In rhinoceroses, M . bovis infections have been occasionally reported in captive individuals [6,7], and extremely rarely in free-ranging animals. In 2009, localised incidental BTB lesions were reported in a semi-captive black rhinoceros ( Diceros bicornis minor ) in South Africa [8] and, in 2014, a semi-free ranging black rhinoceros was found dead with extensive lesions consistent with BTB from which M .…”

Risks from disease caused byMycobacterium orygisas a consequence of Greater one‐horned Rhinoceros (Rhinoceros unicornis) translocation in Nepal

“…Evidence suggests the exposure of GOH rhino to Mycobacterium orygis and susceptibility to infection are both low: infection and disease associated with Mycobacterium orygis has only been identified in one GOH rhino in Chitwan National Park, despite their relatively high density in Chitwan (601 individuals in 932 km 2 ), while no artiodactyls have been found infected in the same Park (Thapa et al, 2017). The susceptibility of Rhinocerotidae to infection and disease from other Mycobacterium species is apparently low, judging by the sporadic cases of Mycobacterial disease reported in these species, for example only one case of Mycobacterium bovis infection in an adult black rhino in the Kruger National Park, South Africa had been reported by 2016, despite Mycobacterium bovis-associated disease having been present in other species in the Park since 1950-1960(Michel et al, 2006Miller, Buss, van Helden, & Parsons, 2017;Miller, Michel, Helden, & Buss, 2016). A second reported case of Mycobacterium bovis infection in free-ranging black rhino was detected in Mkuzi game reserve in South Africa (Espie et al, 2009;Michel et al, 2006 Exposure assessment for Mycobacterium orygis as a source hazard GOH rhino and other susceptible species already present in Bardia National Park may be exposed to Mycobacterium orygis via direct and indirect transmission from infected released animals by (a) air droplets, which are inhaled by the susceptible animals, and once the Mycobacteria reach the pulmonary alveoli they invade and replicate within endosomes (McVey et al, 2013), (b) ingestion, (c) percutaneous transmission, through breaks in the mucosal membrane, (d) via fomites, where the pathogen can have a survival time of over three months (Kramer et al, 2006), (e) venereal transmission or through (f) vertical transmission; calves becoming infected via ingestion of contaminated milk (Coggin, 2006).…”

Wildlife Tuberculosis: An Emerging Threat for Conservation in South Asia

“…The strongest impact of M. bovis for wildlife conservation is probably in South Africa where the bacillus is maintained within African buffalo and has spilled over into 13 different wild animals including protected species like the lion, cheetah, and greater kudu [34]. Recently, TB caused by M. bovis in free-ranging rhinoceros in Southern Africa has been considered as an under recognized threat [35].…”