Southeast Asia Samples Bats, Pigs and People to Track New Viruses
Scientists backed by USAID are hard at work to stop deadly diseases like Ebola and Zika before they can appear in humans.
The fruit bats hanging out in trees next to Thailand’s Wat Luang Phrommawat temple are a rowdy lot. One would think after a long night of carousing and feasting on mangoes, papayas and bananas they would be in for a long afternoon nap. Not this flapping, screeching crowd.
These swinging socialites are all about putting on a show, and it is certainly entertaining for visitors — as long as you keep a wide berth from the base of the massive Burma padauk tree.
But here in Chonburi Province, an hour’s drive southeast of Bangkok, a small group of veterinarians get to see another, radically quieter side of these bats — Lyle’s flying foxes, to be precise.
With USAID support, they catch them in wide, thin nets and bring them down for sampling and inspection. It’s part of groundbreaking new field work to discover more about how viruses that could prompt a future pandemic jump between animals and humans. And, it’s a three-step diagnostic dance choreographed on the heels of SARS, Ebola, Zika and pandemic influenza. And the routine goes like this.
Step one — bats. Long before sunrise, the USAID PREDICT project team puts on raincoats and stretches out plastic sheets under trees to catch urine from roosting fruit bats overhead. Later in the morning and into the afternoon, the team traps about 100 bats in nets strung up high, removing them gently in gloved hands and putting them in white cloth bags hung on a clothes line. Skilled technicians then carefully remove the bats from their individual bags, draw blood and take swab samples before painting the bats’ claws bright purple for identification. The bats, hearts beating wildly in the excitement, take in a long draw of pink sugar water before they are released, slowly climbing up the tall trees from whence they came.
These researchers are keen to find out more about the bats that provide essential services such as fruit tree pollination, but can also host some of the world’s deadliest viruses. All the samples from the day’s work are cooled down by liquid nitrogen to minus 320 Fahrenheit in steel tanks and sent back to Bangkok for analysis.
Step two — pigs. Less than 20 miles from the bat colony lie several small-scale and commercial pig farms. Here too, USAID is busy sampling, this time with veterinarians from the Thai Ministry of Agriculture and Cooperatives. They are following a similar protocol to the bat sampling. The squealing, excitable pigs selected for this sampling are not as docile as the bats from phase one, but once they settle down the procedure only lasts a couple minutes until they are back to their feed.
“Studies of various livestock diseases are important, especially those in swine given a high number of pig raisers in the province,” said Dr. Saroch Ngarmkum, director of the Chachoengsao Provincial Livestock Office. “The information from results and analysis of the sampling collected will help us in the planning and control of swine disease transmission. It is important for pig farmers to be educated so that they can find ways to improve their methods and prevent diseases from transmitting to other nearby provinces.” This surveillance can also trigger early detection of viruses moving from bats to pigs and other domestic animals, which in turn can threaten human health.
Step three — people. A good stone’s throw from the temple, the staff of Wat Luang Tambon Health Promoting Hospital carries out a behavior survey to determine the risk of infection for the people living in the shade of the bat-laden trees and sample their blood, urine and saliva. In 2017, the simultaneous surveillance of humans, their domestic animals and wildlife in close contact at locations with spillover risk is the innovative new piece of disease detection now getting underway in Thailand, Laos and Cambodia with USAID support. The local community, with the backing of volunteers, is fully onboard.
Close Quarters
“The study is very good as it provides baseline data as well as general health check-up for villagers, many of whom cannot afford it,” said Thanaphol Puttharaksa, leader of the 62 community health volunteers covering seven villages. “The people are glad that the team from Chulalongkorn University comes to conduct the surveillance and provide the knowledge to villagers, because in the past, they had no idea they can get infected from a bat.”
Following community education, they now know not to eat fruit left over from a bat or touch live or dead bats with their bare hands. They also stay clear of bat urine and feces.
Along the fruit bat flight path is Sanan Chaingam’s small pig farm in Wat Bot sub-district of Phanat Nikhom District. He’s been raising pigs for over 30 years, earning enough income to take care of his family.
“I am not particularly concerned about bats,” he said, speaking up over the grunting of his prized sows. “We have been living near the bats for such a long time, and I have never heard about any report of human or pig infected with the virus from bats. I’m pleased to be part of this study, though. It gives me confidence, and I feel safe.”
But local officials remain vigilant.
“The bats are part of our community, and we live very close together. We consider it a high risk situation,” said Sonjai Pornpattananikom, director of Wat Luang Tambon Health Promoting Hospital. She is helping conduct behavior surveys for all of the people tested in her community. “It is good to have USAID and the [Thai] government support the study and ongoing surveillance in our community.”
Sampling and testing procedures are guided by USAID PREDICT, a project that over the past five years has worked in 31 countries to detect 1,000 new viruses in its quest to help map and prevent emerging infectious diseases that can rapidly become pandemics and threaten global health. Deforestation and ever-expanding farmland reduces natural habitat and forces bats, rodents and other forest dwellers into closer contact with livestock and people.
“USAID’s approach is making use of land use change, agricultural production, demographic data, human behavior studies and years of surveillance to help refine the picture of where and how pandemics get their start,” said Dr. Daniel Schar, the senior regional emerging infectious diseases advisor at the USAID’s Regional Development Mission for Asia. “Armed with these insights, we can now shift strategies toward prevention, identify and contain pandemic-prone viruses and reign in those practices that are driving the emergence of new diseases.”
New Piece of the Pandemic Puzzle
The new study is filling a key knowledge gap as scientists race to fence in viruses before they can unleash and pose serious health threats around the world. A leading mind and champion of the USAID PREDICT work is Dr. Supaporn Wacharapluesadee of the Thai Red Cross Emerging Infectious Health Science Centre at Chulalongkorn University.
Working with provincial health authorities, she helped orchestrate the sampling of volunteers in Chonburi. Those samples are then screened in her lab against the same five viral families that serve as the foundation of the USAID-supported surveillance in bats, pigs and humans. For the curious, these viral families are coronavirus, influenza, paramyxovirus, flavivirus and filovirus, which include such notorious offenders as SARS, Nipah, Zika, West Nile and Ebola viruses.
“We will go back to the lab and do the testing using the same protocol as in bats,” said Supaporn. “If we find any positive viruses in human specimens these can be compared with other countries where they might have similar pathogens.” By cross-referencing results from wildlife, livestock and human sampling, health officials are better placed to spot early cases of viruses jumping from animals to people, hopefully halting an emerging outbreak in its tracks.
This lab is part of a network of 20 national labs supported by USAID and its partners, including the USAID PREDICT consortium and the Food and Agriculture Organization, across South and Southeast Asia that use polymerase chain reaction machines that take small fragments of genetic material and make a billion copies so they can be more easily detected.
And increasingly, officials from the 10 Association of Southeast Asian Nations (ASEAN) governments are joining USAID and its partners to bring together animal and human health professionals to detect, and respond to disease outbreaks quickly and set up systems to prevent them under the approach now commonly known as One Health.
“There are possibilities that a pandemic could start in Southeast Asia,” said Dr. Wantanee Kalpravidh, regional manager of United Nations Food and Agriculture Organization (FAO) Emergency Center for Transboundary Animal Diseases. She noted the experience with SARS, when the disease spread to several countries within a few weeks. Yet, the preparation continues. “We are on track in producing information, we are on track in helping the countries plan, but on a smaller scale. So scaling to be the national policy still requires lots of policy advocacy.”
Thailand’s animal health experts have recognized the timely importance of the new collaboration. “The partnership with USAID and FAO is very important,” said Dr. Weerapong Thanapongtham of Thailand’s Department of Livestock Development. “It is widely known that bats are able to transmit many diseases such as Ebola, MERS and Nipah. Having support and cooperation from international organizations provides a good opportunity for joint research projects.”
Thailand is one of the first countries to conduct human sampling under the USAID PREDICT project. The community sampling will be helpful to understand pandemic risk at a global level.
“Any spillover event in a community could become a global threat,” said Dr. Kevin Olival, associate vice president for research at EcoHealth Alliance and USAID PREDICT program coordinator for Thailand and Indonesia. “We are piecing together all of these parts of information from around the world to better understand the risk of diseases emerging into people, particularly diseases that jump between animals and people — wildlife, domestic animals and humans.”
And according to Dr. Sudarat Damrongwatanapokin, USAID’s Regional Animal Health Advisor, predicting that critical link between the three groups through the One Health lens near the source of viruses could potentially be the key to preventing the next pandemic.
“The community is at the front line of disease detection through coordinated surveillance with officials from the animal health, human health and wildlife health sectors,” she said. “Disease always occurs at the community level, so we need the active participation of local people to help us succeed.”
About the Author
Richard Nyberg is a senior regional communications adviser at USAID’s Regional Development Mission for Asia based in Bangkok, Thailand.
