Hindustan Times (Delhi)

After Bronx tiger tests positive, zoos, reserves put on high alert

- Jayashree Nandi letters@hindustant­imes.com

nNEW DELHI: The environmen­t ministry on Monday advised the chief wildlife wardens of all states to take immediate steps to prevent the spread of the coronaviru­s disease (Covid-19) in national parks and tiger reserves, including restrictin­g the movement of people near national parks and sanctuarie­s.

This was in response to the report of a Malayan tiger testing positive for Sars-cov-2 in New York’s Bronx zoo.

Is it far-fetched to imagine that wildlife in national parks or outside could be infected with Covid-19? No. In fact, scientists have flagged that informatio­n on potential animal hosts of the virus is crucial to deal with the pandemic. This is because the virus could find new hosts, which can infect other animals or lead to the re-emergence of the disease in humans. This kind of possible cross-species transmissi­on of infection can be dangerous, they said.

A few reports of pet cats and dogs testing positive have surfaced in the past couple of months from Belgium and Hong Kong but a Malayan tiger testing positive (first infection in a wild animal after outbreak) has got many scientists worried about the potential of new animal reservoirs for Sars-cov-2, the virus that causes Covid-19, outside China.

“Inter species transmissi­on is extremely worrisome, whether it be from pangolins, bats, civets or tigers. Clearly mammals are vulnerable but we don’t know enough at this point. From the science so far, it appears that there are multiple strains evolving and the potential to find new reservoirs exist,” said Krithi Karanth, chief conservati­on scientist at Centre for Wildlife Studies and Adjunct Associate Professor, Duke University (USA).

“Human activities, specifical­ly consumptio­n of wild meat, wildlife trade, habitat change and fragmentat­ion, are leading to increasing contact between people and wildlife. Multiple zoonotic diseases have emerged, resulting in transmissi­ons between wildlife, domestic animals and people. Covid-19 is perhaps the most destructiv­e example,” she added.

On Monday, the National Tiger Conservati­on Authority (NTCA) also directed states to observe tigers for symptoms like dry cough or laboured breathing through direct observatio­n and camera trapping, careful handling of post mortem of dead tigers in consultati­on with state veterinary officials and safeguardi­ng of staff with personal protective equipment (PPE), among others.

NTCA has asked states to send samples of suspected cases to laboratori­es approved by the Indian Council for Agricultur­al Research.

The Central Zoo Authority of India (CZAI) also issued an advisory to all zoos in India, asking them to remain on high alert and monitor animals for any abnormal behaviour. Samples of any suspect animals, if any, have to be sent to animal health institutes to initiate Covid-19 testing, the advisory added.

“Sometime in the past at an unknown time the Sars-cov-2 crossed over to humans through an intermedia­te host. But we haven’t found that host animal. Cross-species transmissi­ons happen all the time. The case of the tiger getting infected in Bronx tells me a few things. First, that there is a lot of infection in New York. Second, we should study if cross-species transmissi­on is happening. Best would be to sequence the virus in the tiger and the humans working close to the tiger and to see the variables. We must also study the tiger very closely to see how long and how much virus it is shedding, and finally investigat­e if the human got infected by the tiger or vice versa. A body of knowledge about this is very important at this point,” said a senior virologist, who declined to be named because of government advisories on not commenting on Covid-19.

This can be done with more tests in labs and natural conditions, scientists said. “I’m not sure we have enough evidence to say that the Covid-19 virus has several potential animal reservoir hosts based on current spillback (transmissi­on from humans to animals) evidence. We need to do a lot more testing and lab experiment­s to see if any other species can maintain reservoir host status for this virus. Thus far, all we know is that a few cases of spillback have been observed. What are the consequenc­es of this? Does the animal get sick? Is it able to transmit the virus via the same routes (aerosol or droplets)? These are all questions that need further investigat­ion,” said Abi Tamim Vanak, fellow, Wellcome Trust and senior fellow at Ashoka Trust for Research in Ecology and the

Environmen­t.

“We do not know much about the condition of the animals inside the forests, There is a possibilit­y of tigers contractin­g the infection. So we have asked field staff to observe the animals very carefully and look for signs of Covid-19 while conducting post mortem,” said AK Nayak, member secretary, NTCA.

“It doesn’t surprise me that a tiger has got infected. This is because during the SARS outbreak in 2002 (the Sars-cov-2 virus is 85% similar to the SARS virus) civet cats were reservoirs and there were mass killings of civet cats which may have led to spillover then. So the feline or cat family has a pre-dispositio­n to the virus. But so do bats and many other animals. At this point we cannot rule out the possibilit­y of cross-species transmissi­on. We need study and documentat­ion of animal reservoirs,” said Dr Nivedita Gupta, scientist at Indian Council of Medical Research, (ICMR)— country’s apex biomedical research organisati­on.

Several scientific studies in the past have shown how coronaviru­ses are common among several wild species, including bats, pangolins, racoon dogs, masked palm civet, monkeys and mice.

According to United Nations Environmen­t Programme (UNEP), 75% of all emerging infectious diseases in humans are zoonotic and that these zoonotic diseases are closely interlinke­d with the health of ecosystems.

While scientists have been stressing on the impact of loss of biodiversi­ty, a new study estimated that there has been a 71.5% reduction in large forest patches (> 10,000 km sq) in Central India and the Western Ghats if the existing size of forest patches are compared to a scenario that excludes land taken up by infrastruc­tural projects. The study, by scientists from the Foundation for Ecological Research, Advocacy and Learning (India), Centre for Wildlife Studies (India), University of Goettingen (Germany) and Columbia University (US), was released on Monday.

 ?? PTI ?? A sanitation worker disinfects a tiger's enclosure at the Alipore Zoo n in Kolkata, West Bengal on Monday.
PTI A sanitation worker disinfects a tiger's enclosure at the Alipore Zoo n in Kolkata, West Bengal on Monday.

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