Credit: DNP

SPECIAL REPORT: Call them “Virus Hunters”

A team of veterinarians, ecologists, and virologists has been chasing viruses in wildlife hard_to save people’s lives

If not on his routine duty, DNP’s senior veterinarian Pattarapol Maneeon would drop his pack of medical supplies and a tranquillizer gun and switch his uniform to a biosafety suit in a chase for one animal critical to the country’s public health; a bat.

Since emerging infectious diseases have become more and more critical to the country’s public health, especially amid the emergence of Coronavirus disease or COVID-19, the new global public health threat, veterinarians of the National Parks, Wildlife, and Plant Conservation Department like Dr.Pattarapol have come up with a plan to reunite with biologists like Associate Professor Prateep Duengkae from Kasetsart University’s Faculty of Forestry, and virologists like Dr.Supaporn Wacharapluesadee from the Emerging Infectious Diseases Health Science Center of King Chulalongkorn Memorial Hospital_this time to chase for all 23 bat species reported in the country in a bid to conduct more in-depth surveys and records of new infectious diseases derived from those bats, especially coronaviruses.

For almost 20 years, this ad-hoc specialist team has pursued the mission of “active surveillance” on emerging infectious diseases from wild animals, particularly bats.

The work is considered to be the forefront of prevention and control of emerging infectious diseases, which pose a challenge to the country’s public health capacity every time they emerge, and integrated into the 20-year national strategy already.

“The world now has embraced an integrated public health approach which is called, One Health, meaning everything is interconnected. These too cannot be separated anymore_animal health science and public health.

“This is active surveillance against any newly emerging infectious diseases from wild animals to people. If effective, we can level up our prevention and control of outbreaks to not spread on a large scale,” said Dr.Pattarapol.

Dr.Pattarapol in a biosafety suit while chasing for bats.
Credit: DNP

Why wildlife, and bats?

A number of research and studies, including the latest citation made by Wildlife Conservation Society in a wake of Coronavirus disease, have shown that over 70% of newly emerging infectious diseases are zoonotic, with wildlife being identified as the prime reservoirs.

Throughout history of infections, it is learned that bats are the prime reservoirs carrying various viral components and such, especially coronaviruses, and therefore become critical sources of several critical emerging infectious diseases of modern time, including MERS (Middle East Respiratory Syndrome that occurred in the Middle East in 2012) and SARS (Severe Acute Respiratory Syndrome that occurred during 2002-2003, mainly in China).

However, bats themselves are normally not infected and that is the reason why they are called “reservoirs”.

Once viruses from bats are transmitted to other intermediate hosts, they can be re-assorted, exchanged, and amplified to the point they can mutate and become transmittable to humans.

Surveillance on newly emerging infectious diseases from bats is, therefore, more and more widely adopted as part of prevention and control of emerging infectious diseases in humans.

A Lyle’s flying fox found to carry a critical disease, Nipah.

The chase

In Thailand, the study on bats in regard to this aspect began around 15-20 years. When it started, the researchers received funding from the government to survey on viruses in bats to see their genetic diversity in an attempt to assess infection risks to humans.

As the world learned more about bats that they acted as reservoirs of critical diseases to humans, especially by coronaviruses they carried, the team became more serious about the study and surveillance on emerging infectious diseases from wildlife to humans.

They received funding from USAID, under the program called PREDICT USAID, which is part of the worldwide program, Wildlife Trust PREDICT that was supported by the US-based Wildlife Trust and in collaboration with Wildlife Conservation Society, Global viral Forecasting initiative, and Smithsonian.

Under the Wildlife Trust PREDICT, the integrated team of scientists tried to initiate the Emerging Pandemic Threats, or PREDICT worldwide with an aim to develop and introduce warning systems and risk assessments on newly emerging infectious diseases from wildlife to humans for countries with high risks.

The program focused on studies on the diversity of viruses in wildlife with transmission potentials so that the new body of knowledge could facilitate the development of assessments on health risks of emerging infectious diseases from wildlife and models to help project the risks and guide planning against potential diseases.

It was hoped that this body of knowledge and new systems derived from it would be integrated into public health safeguard systems of countries involved.

So far, it is known that at least two prime genera of coronaviruses could be transmitted to humans; be they alpha and beta. The two others have had no confirmed reports yet; gamma and delta.

Throughout the years of 2011 to 2018, this integrated team of researchers kept chasing for bats all over the country, learning that at least the country hosted 139 bat species, including the ones that carried coronavirus that caused MERS like bamboo bats, Tomb bats, and Pipistrelle bats.

They collected droppings from 4,021 bats by a rectal swab technique and extracted their DNAs to test in a lab.

The team found that among those samples, 57 carried coronaviruses; 19 were alpha, 36 beta.

Furthermore, 8 samples showed positive to MERS viral components; 2 from Greater bamboo bats, and 6 from Wrinkle lipped bats, while some few more showed positive to SARS viral components from an intermediate round leaf bat, and Malayan horseshoe bats, which were the same family as those also found in China.

Although the team learned about the presence of some viruses with potentials to contract people here, up until this point, there have been no reports of infections in humans from those viruses here yet.

Dr.Pattarapol said the study at least has served as a warning sign for Thai people to keep a close watch on potential infections from those viruses as they can mutate over time and transmit to people both indirectly and directly.

“We need to learn what risks are, the probability of virus infections to humans. It depends on several things, but among those are the viruses’ capacity, in hiding, in mutating, and others.

“The study and surveillance on newly emerging infectious diseases from wildlife to humans, therefore, help us predict what could happen, and I make this a success when our research results reach policy makers and are integrated into our public health system for more effective prevention and control of emerging infectious diseases,” said Dr.Pattarapol, while adding there are a number of challenges ahead, including capacity building, as well as public awareness-raising.

Assoc. Prof. Prateep with a textbook on bats.

From wildlife to humans

As an ecologist specializing in bat biology in the country, Associate Professor Prateep realizes why diseases from wild animals can jump to humans.

Besides some probability that the diseases can jump to humans directly via the reservoirs, like bats, this process is generally considered as being rare. It is rather human activities that bring those diseases close to themselves, Assoc. Prof. Prateep pointed.

Assoc. Prof. Prateep said normally wild animals do not succumb to diseases they carry and that’s the reason why they are called “reservoirs”.

However, when those diseases jump to intermediate hosts, which may be other wild animals, viral components could be amplified, with genes being exchanged or re-assorted.

And once those wild animals come to contact with humans, this process increases chances for those diseases to jump to humans and be transmitted to them, he said.

This is made possible with human activities including habitat encroachment as well as wildlife trafficking and trade, he concluded.

“It’s not quite right to blame animals, because mostly it’s us who bring those diseases close to ourselves, increasing our risks. Bats, for example, have lived in parallel to us for a long time, but once COVID-19 has occurred, we then have put blame on bats. This is not right because it’s us who interrupted their world and increased the risk to ourselves,” said Assoc. Prof. Prateep.

Besides suppression against illegal activities that could increase risks to humans like wildlife trafficking and trade or forest encroachment, Assoc. Prof. Prateep said surveillance on emerging infectious diseases from wildlife to humans is crucial to the overall work of prevention and control of newly emerging infectious diseases in the country.

The work, he said, has helped build up a new body of knowledge and protocols about new infectious diseases in wildlife that could help scientists trace back to the origins and identify them for effective public health prevention and control.

As diseases change over time due to mutation processes of genetic components, they should be monitored over time too, the process Assoc. Prof. Prateep calls, “active surveillance”.

In search of infectious diseases, the scientists have also been trying to resolve a puzzle to see why reservoirs like bats are tolerant to several diseases.

This, Assoc. Prof. Prateep pointed, might be the key to the cure for humans, another reason why the work cannot stop.

Assoc. Prof. Prateep said the work needs continuity, and more capacity building among scientists is what is also needed. But so far, there is only their team working on this (with the limited budget), which Assoc. Prof. Prateep said is not enough.

“The implication of what we have been doing for all those years is trying to get to the origins of emerging infectious diseases. We have been learning about them and managing them to level up our public health prevention and control against the diseases.

Prevention and protection is always the best approach in fighting with an outbreak because once they become an outbreak, it literally gets out of our hands,” said Assoc. Prof. Prateep.

Wildlife trade is still rampant in local markets in Southeast Asia.

Prevention and control against emerging infectious diseases

Dr.Supaporn said the rate of infections of emerging diseases in humans largely depends on a period of time used to detect and identify the diseases.

The earlier the diseases are detected and identified, the lower the chance of an outbreak. So, early detection of the diseases and the surveillance on emerging diseases from wildlife to humans has an implication to the success of prevention and control of newly emerging infectious diseases in humans, she said.

With the database built up along with the protocols and lab capacity building, the virologists could quickly detect the diseases and identify them before reporting them to policymakers to come up with responsive policies and directives against the diseases, Dr.Supaporn explained.

COVID-19, for instance, had been detected by the team of Dr.Supaporn in early January even before China released an official confirmation of the disease.

This happened after the team had received samples for a lab test from a suspected Chinese traveller before finding out within one day by the protocol and database available that it’s the novel coronavirus.

“We have a protocol to pursue as we have practised this for years from the work, that’s the reason why we detected it quickly and reported to our policymakers fast,” said Dr.Supaporn.

Dr.Supaporn said surveillance on emerging infectious diseases from wildlife to humans is about preparedness right start at the origins.

Scientists can learn about newly emerging infectious diseases at their origins. Even though they are not yet transmissible to people, but from the knowledge and database built, scientists can know where they are or what host them and can trace back to them when needed, she said.

“It’s an accumulation of knowledge about emerging infectious diseases as well as experience to deal with them so that we can handle them effectively when the time comes, especially at a policy level.

“Bear in mind that like its name, a newly emerging infectious disease is new every day, it occurs every day, and if we do not follow or monitor them, we would never know and keep up with them. We would never have the knowledge to back our reaction against them, and effective surveillance would never have a chance,” concluded Dr.Supaporn.

The team at the recent seminar, From Wild Meat to Virus: A wake-up call on illegal wildlife trade, on an occasion of World Wildlife Day held by National Science Museum on March 3.