Tuberculosis (TB) is a reemerging disease in captive elephants, with increasing numbers of cases reported in the past two decades from different countries. Asia in particular houses a large population of captive elephants including 3400-3600 of them in India alone. Reports from Asian countries indicate that it is not unusual to find TB on postmortem examination in captive elephants.
According to Elsevier, a medical Journal published in May 2011, of the 446 elephants living in the U.S. between 1996 and 2013, fully 57 (12.4 per cent) had received a diagnosis of TB infection, a surprising number given the low rates of TB among humans in the U.S.
Dr. Susan Mikota has been investigating TB since it emerged in elephants in the U.S. in 1996. She is the Director of Elephant Care International that supported the initial elephant TB study in India. Research in Southern India found 20 per cent of the 350 elephants in Kerala were reactive on the STAT‐PAK test, a precursor to the currently available DPP Vet TB test, licensed by the USDA as a screening test for TB in elephants.
In Kerala, 19 captive elephants have died this year through October. Animal welfare groups suspect at least two were TB-infected. Heritage Animal Task Force Secretary Mr. Venkitachalam decries, even after the orders from the Guruvayur temple principal secretary, the authorities failed to segregate 15 TB-suspect elephants. Additionally, the HATF secretary says he is convinced that two elephants from Guruvayur Temple's Punnathoor Kotta that died this year were infected with TB:
"[A]s 13 of them stand on their urine and feces creating a prime environment for diseases like foot rot and TB. And sadly, post mortem results are never made public."
In an exclusive interview with me, Dr.Mikota voices similar concerns, "the elephants at that temple are highly stressed and live in crowded conditions with many management questions, all of which could increase susceptibility to disease."
For humans, TB is already a pandemic, and reported to be one of the top 10 causes of death worldwide. According to World Health Organization's 2016 report, six countries account for 60 per cent of the global cases of TB, with India leading the count at 20 per cent, followed by Indonesia, China, Nigeria, Pakistan and South Africa.
"Given how endemic TB is among humans in India and how political TB is as a disease I think there is reason for concern. Certainly from a One-Health standpoint, elephants are part of the TB equation in the range countries," says Mikota.
The One Health movement argues for the integration of human and veterinary medicine, so the health and well-being of all animal species can be protected. Under the One-Health umbrella is a branch called zoonotic diseases, which simply means diseases caused by microorganisms that can spread from animals to humans.
M. tuberculosis, the human TB strain spreads among humans through respiratory droplets. Inter-species transmission of TB between elephants and humans has been documented, and public health evaluations in the USA have recorded a risk for human exposure from infected elephants.
"In the U.S. many facilities that have had TB in elephants have also had staff that reacted on skin test and were treated. The recent TB cases at the Oregon Zoo in Portland also had human cases reported in the news."
But as far as Kerala is concerned, one of the vets who spoke with me on condition of anonymity said, he fears reverse zoonoses - that is TB is being spread from humans to elephants, given the close interactions with elephants in religious places.
Of dire concern to veterinarians is that undetected elephant TB may spill over from captive elephants to free-ranging wildlife. There were reported cases in a wild elephant in Sri Lanka and one in an African elephant that had been raised in an orphanage and was released. So, TB is already in the wild probably because of factors like habitat encroachment that make the spread of disease easier.
"This is my greatest concern. That TB would become established in the wild. There is not much we could do. Spread of M. bovis (the bovine strain) is already a huge problem in South Africa among buffalo in Kruger Natl Park and has spilled over into 10 other mammalian species."
TB could be catastrophic for the Asian elephant population, for three reasons. First, Asian elephants are an endangered species, teetering ever so precariously on a delicate balance. Secondly, more than 60 per cent of elephants live in India, according to a world renowned ecologist Dr. Raman Sukumar. Thirdly, and most importantly, TB is endemic in India, making it imperative for the nation to adopt proactive measures.
Early detection is key to preventing the spread of TB. Rather than the age old way of diagnosing TB using the sputum from the trunk, which is extremely cumbersome and time consuming, a rapid method, the DPP, licensed by the United States Department of Agriculture can be used to screen elephants. This is a blood test that identifies antibodies against TB that can predict TB months and sometimes years before the disease can be confirmed by culture. Elephants identified as TB suspects based on this test can undergo early treatment or increased testing (by culture). This in turn can limit the transmission of TB to other susceptible animals and humans.
Among other suggestions to prevent the spread of this deadly disease, human-elephant interactions need to be limited. Stringent enforcement to maintain safe distance between the elephants and general public is vitally important. Infected elephants need to be monitored, and segregated or treated following a strict regimen. Mikota is concerned:
"There is clearly TB in elephants in India. Unless a plan is put into place TB can become a political nightmare. The 2010 Elephant TB Guidelines in the U.S. and those used in Nepal can be a starting point. The health and well-being of both humans and elephants is at stake. TB is a serious disease and must be approached from a One-Health standpoint."
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