The virus hunters

Researchers from Kasetsart University collect bats at the Khao Chong Pran cave in Ratchaburi province, 12th September 2020

Researchers from Kasetsart University collect bats at the Khao Chong Pran cave in Ratchaburi province, 12th September 2020

Dr Supaporn Wacharapluesadee had long feared that a deadly virus with its origins in bats would spill over to humans. The warning signs were there, and the creatures have a track record when it comes to zoonoses – infectious diseases that make the dangerous leap from animal to human. SARS (Severe Acute Respiratory Syndrome), MERS (Middle East Respiratory Syndrome) and Ebola are all thought to have their origins in the species. So when the phone call came from Thailand’s ministry of health in early January, Dr Supaporn and
her team at the Thai Red Cross Emerging Infectious Diseases laboratory at Chulalongkorn University in Bangkok were ready.

“The authorities asked me whether I could identify the disease,” says Dr Supaporn, who has specialised in viruses originating in bats for around 20 years. She was sent several samples of mucus and saliva from travellers who had arrived in Thailand from Wuhan in China with an unknown form of pneumonia. “It was a huge challenge for me and my team, to diagnose this unknown pathogen. I immediately thought about two virus families – coronavirus, which can cause MERS, SARS and other diseases, and influenza.”

Researchers set up a net to catch bats in the Khao Chong Pran cave, 12th September 2020

Thousands of bats fly out of the Khao Chong Pran cave at sunset

A sample from a woman who arrived in Thailand on a flight from Wuhan on 8th January gave her team what they needed. “We had a partial genome of the virus, which when compared to the samples in a DNA database wasn’t a match for any human pathogen, but it was something like a 93 percent match for a coronavirus found in horseshoe bats. We alerted the authorities of our finding on 9th January, while China did not confirm the disease [to the World Health Organization] until a day later.” Dr Supaporn had independently diagnosed the “unknown pneumonia” as caused by a coronavirus with bat origins. “Of course, at that time I never would have thought that this virus would travel around the world,” says Dr Supaporn.

In the months since Covid-19 spread across the planet, a lot has been learned about how people can keep themselves and others safe, how to slow the spread of the disease and how to best treat patients with severe cases. In November 2020 the drug-makers Pfizer and Moderna both announced that their Covid-19 vaccines appear to prevent infection in 90 percent of cases. A potential way out of this pandemic is in sight. But what about the next pandemic, and the one after that? What can we do to prevent zoonotic diseases from reaching humans in the first place? That’s where Dr Supaporn and her fellow virus hunters come in.

Kasetsart University ecologists sort bags of bats they collected from inside the cave

To the bat cave!

In September, Bangkok-based photographer Lauren DeCicca visited central Thailand to document the work of Dr Supaporn and her team. “In Ratchaburi province, bats are part of daily life,” says DeCicca. “Dr Supaporn’s group set up a makeshift lab next to the Khao Chong Pran temple, which has traditionally been a place where families gather every night to watch bats float out across the sky from a cave behind the building. Between 5pm and 7pm, millions of bats fly out of the cave, making it the perfect place for virus experts such as Dr Supaporn to carry out their research.”

“It isn’t yet known why bats harbour so many viruses,” says Dr Supaporn, whose team includes ecology students from Kasetsart University in Bangkok and forestry experts from Thailand’s national parks department. “Some researchers believe that bats have a special immune response, which means that viruses [that can cause serious harm to humans] don’t make the bats unwell. I believe that there are a lot of coronaviruses [in bats] that haven’t been found yet,” she says.

Her team hopes to find some of these viruses in order to get a headstart on future zoonotic diseases. They also aim to discover whether the specific virus that causes Covid-19 is present in the horseshoe bats of Ratchaburi province, and to assess the possible threat of the bat population to local human residents. It’s not unheard of for people in Thailand to include bats in their diet – in 2006, Dr Supaporn co-authored a paper published in the journal Clinical Infectious Diseases entitled ‘Drinking Bat Blood May be Hazardous to Your Health’.

“I think the coronavirus passed from bats to humans because we got too close to the bats,
or to the wildlife that may be the intermediary between the bats and the humans,” says Dr Supaporn. “We have two main jobs: the first is to detect the viruses, the second is to create simple educational tools to educate people in areas that are high-risk in terms of zoonoses, areas with lots of bats. We need to make this kind of intervention to help villagers protect themselves.”

DeCicca joined in with the Ratchaburi bat hunt, heading into the cave at the temple. “The students put on their protective equipment, went into the cave, held their nets up in the air and within seconds they were full of bats,” she recalls. “In the cave they were catching tonnes of wrinkle-lipped free-tailed bats and afterwards they trekked into the jungle to try and get a different kind of bat from a different opening in the cave. It’s hard work – it was around 40 degrees in Thailand at the time, and they were in PPE suits, trekking through the jungle … After the bats are caught they are put in little bags. It’s funny, the bats head straight to the top of these cloth bags, dangle upside down and then fall asleep.”

The bags are then numbered and put on a clothesline, before being taken to the onsite laboratory, where the ecology students from Kasetsart University take measurements and tissue samples, and the Chulalongkorn scientists take blood and mouth swab samples, as well as painting the bats’ claws so they can be identified if caught again. “We measure the wing, the body, the tail and the ears as these are the key measurements to identify which of the more than 1,200 species of bat we are dealing with,” says Dr Supaporn.
“And we collect the blood and faeces and swab the saliva for virus identification.”

“I’m an animal lover so I was worried about how the bats might be treated,” says DeCicca. “But it was really lovely. At the end the students take the bat in their hands and say, ‘Thank you for your service, thank you for your sacrifice’. They’re all thanked individually and if they missed a meal they’re given a drop of sugar. They are let out of the window and they fly back to the cave on their own.”

Scientists collect a blood sample from a wrinkle-lipped free-tailed bat at the on-site laboratory

A scientist collects a saliva swab from a wrinkle-lipped free-tailed bat at the on-site laboratory at the Khao Chong Pran cave

The claws of a bat are painted so that they can easily be identified if caught again

Waiting in the wings

As of early November 2020, there had been just 59 deaths from Covid-19 in Thailand, only five of which occurred after March. Nearby countries such as Vietnam, Cambodia and Laos have been just as successful at controlling the disease.

This may in part be due to the traumatic memory of the SARS outbreak, which saw nearly 800 people
die in the region in 2002 and 2003, meaning that Asian nations may have been better prepared than those in the West for handling Covid-19. Thailand had long been preparing for a serious outbreak of an infectious disease – a nationwide network of testing centres had been built and protocols for virus detection had been established. In November 2019, the World Economic Forum’s Global Health Security Index ranked Thailand as the sixth best country in the world when it came to preparedness for dealing with a pandemic, the only non-high-income country to make the list. The US and the UK – two of the countries worst hit by the Covid-19 pandemic – were ranked number one and two respectively.

Dr Supaporn’s work was part of that preparedness effort. The World Health Organization has credited Thailand’s “long-standing research on coronavirus strains in bats” for helping it “rapidly ramp up its laboratory and testing capacities and curb the spread of the novel strain that causes Covid-19.” Dr Supaporn’s team’s detection of the virus on 8th January gave the country a headstart in its efforts to curb its spread.

“Thailand has been fantastic at stopping the virus spreading,” says DeCicca. “The contact tracing was so fast and efficient, people were put in isolation if they tested positive, and there’s a huge network of volunteer health professionals helping people across the country to be prepared for situations like this.”

“It’s hard to say exactly what Thailand is doing right and what countries like the UK and the US are doing wrong,” adds Dr Supaporn. “But I have a question – how long have you in the UK been told to wear masks for? We started wearing them when the first cases were discovered in January. It makes a difference.”

For the past decade Dr Supaporn has worked with PREDICT, a project funded by the US Agency for International Development to search for unknown zoonoses. It has collected over 140,000 samples from animals, trained scientists across Asia and Africa and seen teams in 31 countries discover over 1,000 new viruses. Two years ago PREDICT identified a new form of the Ebola virus in bats in Sierra Leone, meaning that authorities had the opportunity to educate local populations about living safely alongside the bats in an effort to reduce the chance of the virus jumping species. In her own research Dr Supaporn discovered the rare but deadly Nipah disease lurking in Thailand’s fruit bats – thankfully it hasn’t leapt to humans. The US federal government halted funding for the PREDICT programme in late October 2019, just weeks before the world learned of a new disease appearing in Wuhan. A successor programme to PREDICT, Strategies to Prevent Spillover, was announced in September 2020.

Dr Supaporn and her colleagues around the world can educate people on the dangers of close contact with bats (or other species) in areas where viruses with the potential to jump to humans are present, while giving the authorities more time to develop early-warning systems and prepare responses to future outbreaks. Such early warnings can also give a head-start to pharmaceutical companies and researchers aiming to develop treatments and drugs.

The studies in Ratchaburi province continue. It isn’t yet known whether the specific virus that causes Covid-19 can be found in bats in the temple cave. We do know, however, that several other types of coronavirus have been found in the Ratchaburi bats. “They might jump to humans or other animals one day,” says Dr Supaporn. She and her fellow virus hunters will do all they can to prevent the next pandemic but they can only do so much. “I am just a scientist and I just report the evidence,” she says. “It isn’t my job to decide what happens next.”

Dr Supaporn Wacharapluesadee speaks to members of her team of ecologists at the entrance to the Khao Chong Pran cave
before the start of the mission

Posted on Thursday, September 14th, 2023 - Categories: #40 - Jul-Sep 2020, App Issues.