Support Provided ByLearn More
Body + BrainBody & Brain

How Vietnam Mastered Infectious Disease Control

ByJoanne SilbernerNOVA NextNOVA Next

It’s the winter of 2003, and Long Thanh Ngo, head of a government biological testing lab in Dong Nai province, watches helplessly as a highly infectious avian influenza virus begins ripping through Vietnam. In a nation heavily dependent on poultry for protein, tens of millions of chickens and ducks are either killed by the disease or culled to prevent it from spreading.

Receive emails about upcoming NOVA programs and related content, as well as featured reporting about current events through a science lens.

The virus even makes the jump to humans. Ninety-three people in Vietnam who plucked or cleaned infected birds or somehow came in contact with their droppings get sick . Mostly, the illnesses begin as normal flu—fevers, aches, pains. Forty-two people develop severe respiratory symptoms and die. Other Asian countries have cases as well, but Vietnam is the hardest hit.

Support Provided ByLearn More
Farmers sell their ducks and chickens at the Ha Vy market outside Hanoi.

The infection spreads like wildfire among poultry, effectively halting the large poultry economy in Vietnam. But veterinarian Long can’t do much. Detecting the virus with his rudimentary tools requires injecting biological samples from birds into poultry eggs, where any viruses would multiply, and then testing the contents of the egg. Results take a week. “By the time we knew it was the influenza virus that can infect humans, there were many flocks infected already,” he says. When talking about that time today, Long looks away. “It was very hard.”

The human deaths, the poultry losses, and the effect on poultry trade galvanized all levels of the Vietnamese government, from local to national. In 2004, the government set up a committee of 27 officials from the health, agriculture, and environment ministries to develop policies aimed at early diagnosis and rapid response to an outbreak. As Long puts it, “If we want to protect people, we have to look at and take care of animals and the environment.”

Long is referring to a concept known as “One Health.” It’s a holistic approach to global health that, over the past decade, has become the dominant force in emerging infectious diseases and global health security. After that first big avian flu scare of 2003, Vietnam became an early adaptor of “One Health” and is now a global leader.

About 70% of new human diseases are like bird flu—they spill over from animals. “Dozens of new infections have emerged from animal populations in the last few decades,” says Michael O’Leary, an infectious diseases advisor with the U.S. Agency for International Development (USAID) in Vietnam. “The intention of One Health is really to help us predict, prevent, detect, and respond at early stages before they become human problems.”

The new strain of highly infectious avian influenza that crippled Vietnam more than a decade ago kills about 60% of the people it infects—a much higher rate than the virus that caused the global flu pandemic of 1918–1919, which had a 2–3% death rate. The H5N1 avian influenza virus that remains in circulation in more than 30 countries , including the U.S., doesn’t spread easily from person to person—yet. “One Health” scientists fear that the virus will mutate or pick up genes from other flu viruses that will allow it to spread easily from person to person.

In some ways, predicting and preventing diseases by going after their origins sounds obvious, but it often doesn’t happen. One Health proponents note that had there been programs to limit human-animal interactions in West Africa or to monitor animal-to-animal transmission of the Ebola virus, the Ebola epidemic that started last year might not have happened—or at least it might have been stopped much sooner.

Viral Hotspot

Southeast Asia is recognized as a hotspot for new viruses—it’s where virus hunters go to figure out what to put in next year’s flu vaccines. O’Leary says that Vietnam’s large population of domestic ducks, chickens, and pigs makes the country particularly vulnerable. “There’s a lot of potential contact with human populations,” he says. And then there’s the continued impact of human activity on forests. “The forests have been extensively logged, and so the opportunities for wildlife, for instance, to come into contact with domestic animals and into contact with humans are great,” he says.

A nurse administers a flu vaccine to a young patient.

Public health leaders in Vietnam are well aware that the country is a breeding ground for new diseases. And they’re sold on One Health, both for Vietnam itself and for global health security. “Diseases used to be enclosed in certain regions or countries,” says Dr. Tran Dac Phu, head of the Ministry of Health’s Preventive Health Department. “Now globalization has made them easier to spread.” In 2003, Vietnam was the second country to report a case of SARS, a disease that whipped up waves of panic as it threatened to spread around the world. It was also the first country to contain the outbreak.

The list of One Health supporters is an alphabet soup of global health agencies. USAID has now spent over half a billion dollars on One Health projects, including $60 million in Vietnam. The Bill and Melinda Gates Foundation has spent $3.1 million on 31 “One Health” projects through its Grand Challenges program. The U.S. Centers for Disease Control and Prevention is helping countries learn how to test for infectious organisms. The Wildlife Conservation Society has programs around the world. The United Nation’s Food and Agriculture Organization, the World Organization for Animal Health, the World Health Organization, the World Bank, EcoHealth Alliance—all have or have had One Health projects. And the list goes on.

Close Contact

Loan Le Minh lives in the bustling village of Long Thanh in the Dong Nai province, an hour and a half drive from Ho Chi Minh City. The 39-year-old repairs the ubiquitous motor scooters that choke the streets in Vietnam’s cities and villages, but his dream is to be a wildlife farmer. A few years ago, he began buying and raising wildlife animals including porcupines, bamboo rats, snakes, and a cat-like animal known as a palm civet, and he’s planning to start selling the meat soon. The meat of all these animals is both popular and pricey in Vietnam.

Just off the path to Loan’s front door, a dozen wooden boxes stacked five feet high line an aisle under a tin roof. The boxes have three shelves each. Loan reaches into one and pulls out a large greyish-brown snake with white zigzag markings. Behind him and around the corner are five cages with about a dozen Asian porcupines, black-and-white spines protruding from their mid- and hind-bodies. His family lives in the same compound, and he’s just a block off the main street of his village—children from the neighborhood like to play amongst the cages.

Chickens awaiting pickup at the Ha Vy poultry market outside Hanoi.

Loan’s dream is to get his pocket farm thriving. But this kind of farming can bring forest microbes into contact with people. Elsewhere, human-animal contact has allowed a number of viruses to spill over. Chimpanzees brought us HIV, the West African Ebola outbreak most likely came from contact with fruit bats, and SARS came to us through palm civets. The close proximity can also provide a place for viruses to mix and trade genes—and become more infectious.

But through One Health programs, the local forestry department and health offices have reached out to Loan and others. They’ve taught him how to handle his animals to prevent infections—keeping them caged in order to prevent bites and scratches, for example, and he knows to alert the authorities if he notices any infections in the animals or the people who handle them.

Tran Van Quang is head of the Dong Nai Animal Health Agency. He followed the Ebola outbreak in West Africa carefully, as well as the deadly outbreak of the Middle East Respiratory Syndrome coronavirus in Korea this past summer . “Animal-related diseases are getting more and more dangerous for humans,” he says.

In Vietnam, at least, the One Health approach is making a difference. Last year poultry in three towns in Dong Nai were hit by avian influenza outbreaks. Animal, forestry, and health officials made sure poultry were vaccinated, 27,000 birds were slaughtered, and the public was warned to look out for sick birds. It took a little over a month to stop, Tran says, but that included 21 days after the last bird got sick. The outbreak was stopped before any humans were infected.

High Stakes

In the global health world, One Health may not have enemies, but it does have challenges, including keeping funders interested in prevention and getting the public on board. It’s the public that has to accept One Health changes, such as switching from backyard poultry to more hygienic store-bought meat.

The first and perhaps biggest challenge to One Health is keeping the funding coming. “I think people around the world, whether it’s Vietnam or any other country, are programmed in a way to deal with emergency response more easily than thinking through preventative measures that would keep the disease from ever occurring,” says Scott Newman, a senior technical coordinator for the UN’s Food and Agriculture Organization in Vietnam.

Monitoring the environment, educating people about animal-based infections, and getting them to change farming and husbandry practices and food preferences requires effort. “The problem is that if you take all these measures, the disease never crosses over to people, and you can’t measure how much money you actually saved as compared to doing an outbreak response,” Newman says.

Within Vietnam, preventative measures haven’t lost their allure yet—the avian influenza outbreak that happened over a decade ago is still fresh on the minds of health officials. “Animal-related diseases are getting more and more dangerous for humans,” says the Department of Health’s Tran Van Quang. One Health is so integral to the country’s budget that its projects are not even broken out in any differentiable way. Plus, foreign aid, such as the $8 million a year from USAID, is a big help.

“Vietnam has made really great progress in promoting One Health,” Newman says. Partnerships on effective detection, education, and prevention programs among departments of health, agriculture, and forestry from the federal to the local level have resulted in only a few sporadic outbreaks in the last few years. All of them were quickly controlled.

Microbes like the avian influenza virus cross borders easily, which is why, for example, Vietnam has been closely monitoring Chinese avian influenza outbreaks. On a global level, the Obama administration has come up with a plan called the Global Health Security Agenda that focuses on using One Health projects to prevent the spread of infectious diseases. In July, the White House announced it is setting aside $1 billion dollars for activities in 17 countries, including Vietnam. It’s a classic One Health strategy—help each country develop the capacity to prevent, detect, and respond to future disease outbreaks by studying animals and the environment as well as humans.

Other countries are in on it as well. In September, Vietnam took part in a meeting in South Korea in which ministers from several dozen countries discussed how to prevent future outbreaks of animal-based diseases. South Korea announced plans to put $100 million into global health security projects in 13 countries.

Changing the System

In northern Vietnam, one of the One Health goals is to redesign the country’s approach to poultry farming. Traditionally, people raise birds—and sometimes pigs as well—at home for their own use or to sell to wholesalers. To epidemiologists, that’s is not a good combination. Avian and pig viruses can jump to humans. And flu viruses—happy in all three species—can exchange genetic material and become more infectious.

The Ha Vy poultry market about an hour’s drive from Hanoi is dedicated to changing the equation. Here 25,000 chickens and ducks a day are sold to wholesalers. From outside the large metal gates, you can hear the clucks and quacks. Inside the gates, the birds mill about in rows upon rows of low-fenced enclosures. The birds have plenty of room, food, and water. For the moment, at least until buyers come and take them off to be slaughtered, the birds seem content.

The four-year-old Ha Vy market demonstrates a One Health principle in action—animal health and human health are intertwined. Here the goal is to create an environment that minimizes the chance that viruses will spread between flocks or to humans. To get into the market, vehicles and people go through shallow pools of disinfectant. Concrete floors make Ha Vy market easy to clean. Cages are elevated from the ground so birds do not sit in their waste, and cages are not stacked one on top of the other. The market is scrubbed daily and closed once a month for a thorough disinfection.

Farmer Quach Thi Hoan selling ducks at the Ha Vy market outside Hanoi.

Government officials check large poultry farms to make sure the birds are vaccinated before they get to Ha Vy. At the market, any animals that look sick are tested. If they test positive, they’ll be killed. “No infected bird has been found at Ha Vy in its four years,” says its manager, Le Xuan Viet.

Do Le Binh, a 56-year-old merchant, appreciates that. Today, he’s sold more than a thousand birds, both his own and for neighboring farmers. He’s all smiles, about to hop on his red scooter to head to his home nearby. “I’m not worried about avian influenza,” he says. “The birds at the market are vaccinated three times.”

Ha Vy is not your hygienic, closed-to-the-world U.S. chicken house, but it is a step up from villagers selling chickens and ducks they’ve raised around the house. In 2006, according to an FAO report, 60% of poultry consumed in Vietnam came from backyard farms. But government One Health policies are slowly changing the entire system by supporting centralized markets with a veterinarian on duty like Ha Vy. The ultimate goal is to minimize the spread of microbes at every stage in the birds’ life cycle. Getting there is a step-by-step process.

Cultural sensitivity is an important part of that, says Newman, the FAO technical coordinator. “The cultural practice of going to these markets and picking out the bird that you want to eat that night is a very strong thing. It has been a way of life for hundreds if not thousands of years, and people strongly prefer to choose the food that they want to consume.”

Modernized Detection

At the lab in Ho Chi Minh City, where a decade ago it took a week or more to identify the avian influenza virus, a USAID program called PREDICT has outfitted Long Thanh Ngo’s lab with five high-tech genetic sequencing machines. The machines can identify highly pathogenic avian influenza in a couple of hours, and Long can do 500 tests in a day. The rudimentary tools he used back in 2003 sit in a corner, repurposed for less time-dependent analyses. Long is ecstatic. It’s One Health at work —focusing on the animal hosts.

“Our system has enough equipment to do the test quickly,” Long says with a broad smile. “We have a lot of experience on how to control the outbreaks and how to communicate to the people and contain the spread of the virus.” Without the equipment? He pauses. “The story of 2003 would happen again,” he says.

In Ho Chi Minh City, veterinarian Long Thanh Ngo can now do rapid tests for bird flu.

Long’s lab is also involved with a Wildlife Conservation Society project that is collecting and testing 4,000 biological samples from the forests—from rats to bats, as he says. They’ve found some new viruses, but so far none that infect humans.

At Vietnam’s Ministry of Agriculture and Resource Development, Nguyen Van Long says the approach has worked well so far. Vietnam has held back avian influenza and prevented a new Chinese avian influenza from coming in.

David Heymann, a One Health proponent and head of the U.K.’s Health Protection Agency, says One Health can’t yet pinpoint where or when the next new infectious disease will emerge. “But it can facilitate its detection and response,” he says. He points to a new fatal virus that showed up in Bangladesh in 2001. Quick research showed bats carrying the Nipah virus were contaminating open buckets collecting sweet date palm syrup. People are now being taught to boil the sap or cover the buckets, effectively preventing infection from a deadly new virus.

So will One Health prevent the next big one in Vietnam or anywhere else? “This is definitely the intent,” says USAID’s Michael O’Leary. Otherwise every country is doomed to dealing with disasters after they happen. “One thing about microbes,” he says. “They don’t respect national borders. It’s been said that a threat anywhere is a threat everywhere.”

At the FAO, chief veterinarian Juan Lubroth says, “We need to have sufficient antennae to tell us when a storm is coming.

This article is part of the “ Next Outbreak ” series, a collaboration between NOVA Next and The GroundTruth Project in association with WGBH Boston.

Photo credits: Joanne Silberner, CDC

Funding for NOVA Next is provided by the Eleanor and Howard Morgan Family Foundation.

Major funding for NOVA is provided by the David H. Koch Fund for Science, the Corporation for Public Broadcasting, and PBS viewers. Additional funding is provided by the NOVA Science Trust.