The fact that the novel coronavirus infection has spread to at least one tiger in the Bronx Zoo has turned the focus on tuberculosis, a bigger threat for captive animals, with animal rights activists calling for steps to help ensure the elimination of zoonotic disease transmission between animals and humans.
Activists have also urged zoos in the U.S., India and elsewhere to phase out vulnerable animals such as the elephant, and sought a ban on the use of elephants, exotic birds and all other animals in circuses.
“It is too early to say whether COVID-19 will end up as a bigger threat than the highly-infectious TB (tuberculosis), which is rampant in the captive elephant population in the U.S. and continues to be contracted by zookeepers,” Laura Bridgeman of the U.S.-based In Defense of Animals told The Hindu via e-mail.
Her organisation has appealed to all member zoos of the Association of Zoos and Aquariums, including the Bronx Zoo, to end elephant captivity in a phased manner. “Like COVID-19, tuberculosis can be transmitted from non-human animals to humans, but its effects can be deadlier because of the possibility of wider contagion through zoo visitors,” she said.
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Manilal Valliyate, the CEO of People for the Ethical Treatment of Animals (PETA) India, cited a 2003 review on “occupational zoonoses in zoos” that said 868, or 61%, of the 1,415 infectious agents causing diseases in humans are zoonotic in nature.
“It is also important to note that more than 70% of the emerging zoonotic diseases have wild animals as reservoir hosts. The major zoonotic diseases that are transmitted from wild animals to humans include rabies, anthrax, leptospirosis, Q-fever, psittacosis, hendra virus, nipah virus, herpes B encephalitis and toxoplasmosis,” the review said.
But TB has been the biggest worry in zoos across India.
“A scientific study in 2012 conducted on 600 elephants in Kerala, Tamil Nadu and Karnataka said there was evidence for high prevalence of asymptomatic tuberculosis infection in Asian elephants in a captive Indian setting,” observed Dr. Valliyate . “Another paper published in 2016 concluded there is evidence to suggest cross-species (between elephants and humans) TB transmission based on a one-time screening of nearly 800 elephants and their mahouts over a period of three years,” he added.
According to the 2016 report, an average 25 elephants die every year in Kerala because of TB, and at this rate the entire captive elephant population would be wiped out from the State in 15-20 years.
An April 2018 evaluation report by the Animal Welfare Board of India revealed that 10% of the captive elephants (10 out of the 91 tested for TB) used for rides and other tourist interactions in Jaipur were found to be reactive in a rapid serological test for TB. The report also cites official documents stating that five Jaipur elephants died of respiratory diseases within five months in 2017.
In the 1990s, the zoo in Lucknow had recorded TB as a major ailment in some herbivores as well as felines.
There is an urgent need for not using elephants in temple festivals and for joyrides to save them as well as humans from tuberculosis, PETA India said. It has also sounded State governments on the importance of quarantining and treating affected animals.