Veterinarians fear devastating disease of livestock might cross international borders
Cow being vaccinated
Photo by Eko Prianto, courtesy of the Food and Agriculture Organization of the United Nations
This cow is among over 1.2 million animals that have been vaccinated for foot-and-mouth disease in Indonesia, which is battling to contain an outbreak that some experts fear could spread to countries that are free of the disease. The government hopes to have used all of its 3 million vaccine doses in the coming weeks and is attempting to procure a total of 29 million by the end of the year.
A large outbreak in Indonesia of foot-and-mouth disease has put the global veterinary community on alert for a potential cross-border spread that could trigger mass cullings of animals and devastate national livestock industries.
While the risk of transmission to far-flung locations is relatively low, tensions are high in neighboring Australia, prompting it to strengthen biosecurity measures that have included deploying detector dogs at airports to sniff out meat and other animal products.
The Australian Veterinary Association, meanwhile, is talking to authorities about how veterinarians in private practice, including companion animal practitioners, might assist in containment efforts should a major outbreak occur Down Under. Veterinarians from overseas, too, likely would be invited to lend a hand.
Since 1986, Indonesia had been considered free of foot-and-mouth — a highly contagious viral disease of cloven-hoofed animals such as cattle, pigs and sheep — until a case was discovered there in late April. The disease has since spread rapidly throughout the archipelagic Southeast Asian nation, infecting 472,667 animals across 24 provinces, according to official Indonesian government figures, though the actual numbers likely are much higher.
Clinical signs of foot-and-mouth include fever and blister-like sores on the mouth, including the lips and tongue, the teats and between the hooves. Sores, though, appear more commonly on cattle. They are less common on pigs and rare on sheep, making the disease identifiable by more subtle signs in those animals, such as lameness and a tendency to lie down more than usual.
Although foot-and-mouth has a relatively low adult mortality rate of 1% to 5%, it kills young animals at a rate of at least 20%, according to the intergovernmental World Organization for Animal Health (WOAH). Survivors can be left debilitated, and the impact on food production can be extreme.
Consequently, foot-and-mouth can be deeply disruptive to cross-border trade in animals and animal products, to the extent that it was the first disease for which the OIE established an official list of disease-free countries.
Disease-free status is enjoyed "without vaccination" — where a foot-and-mouth vaccine hasn't been used recently — by Australia, New Zealand, the United States, Canada, Mexico, the United Kingdom and countries on mainland Europe. The next tier down is disease-free status "with vaccination," where a vaccine has been used in recent months, limiting access to export markets, and for which countries such as Brazil are included. In other places, where the disease is endemic, containment efforts are applied with varying levels of proficiency from country to country.
In a sign of how much nations value disease-free status without vaccination, the U.K. in 2001 culled more than 6 million animals to halt a foot-and-mouth outbreak that had infected a couple of thousand head of livestock there. The mass culling cost the U.K. economy an estimated £8 billion (US$9.78 billion) and delayed national elections there. At least one research paper described the cullings as a "human tragedy," given the strain they put on the mental health of people, including veterinarians, working in rural communities.
The U.S., for its part, hasn't recorded a case of foot-and-mouth since 1929, in California, according to the American College of Veterinary Pathologists. The country experienced its first recorded outbreak in 1870, though that was mild and contained. The most serious outbreak in the U.S. occurred in 1914, affecting 22 states and thousands of animals.
The intensity of the outbreak in Indonesia, the infectiousness of the strain involved and the country's relatively slow response are heightening concerns that more countries are at risk of losing their disease-free status. In June, authorities in the U.K. established an exclusion zone around a pig farm in Norfolk due to a suspected foot-and-mouth case that turned out to be a false alarm.
Fears in Australia have been fanned in recent weeks by the discovery of foot-and-mouth virus fragments in an imported pork-floss product from Indonesia, which has since been pulled from supermarket shelves, and the interception of a passenger from Indonesia with a beef product containing viral fragments.
How likely is foot-and-mouth to spread internationally?
Foot-and-mouth disease, also known as FMD, can spread across international borders via two pathways; direct and indirect. Risks from the direct pathway — encompassing the trade of live animals, meat and other animal products such as milk — are mitigated with trade restrictions and customs checks.
More difficult to quantify from a risk perspective are indirect pathways that entail the illegal carrying of insufficiently treated animal products by individual travelers in their luggage (foot-and-mouth virus, like many pathogens, can be neutralized by cooking). The virus that causes the disease also is apt to contaminate substances and objects, whether it be soil, shoes, farming equipment or human skin.
"On an individual case basis, the risks of cross-border transmission are incredibly low, but if you think about the number of people that are moving between countries, it's a cumulative risk," said Dr. Donald King. "You only need one introduction to potentially cause a big epidemic."
King is the head of the vesicular disease reference laboratory group at the Pirbright Institute, a research institution based in Surrey, England. He also heads up the United Nations' Food and Agriculture Organization World Reference Laboratory for Foot-and-Mouth Disease.
Worryingly, King said the lineage of the virus in Indonesia is an especially active one, known as India 2001e, which caused recent foot-and-mouth outbreaks in Asia, Russia, the Middle East and North Africa.
"It's a viral lineage that we've been tracking now for about eight or nine years, and it's extremely well adapted to spread," he said. "And it has now spread very quickly across Indonesia, so this is a significant event and it has some impact on the risk of onward spread to foot-and-mouth-free countries."
Still, King said the risk of the virus spreading to the U.K. or U.S. is fairly minimal compared to it spreading to countries closer to Indonesia.
The virus can survive only for a limited amount of time outside its host. For instance, on soil, it can survive for two to five days at a temperature above 16 degrees Celsius (60.8 degrees Fahrenheit), up to five weeks at 3 to 7.5 degrees Celsius, and over 20 weeks under snow or at temperatures below 5 degrees Celsius, according to a transmission-risk overview published in 2019.
For its part, Australia also is concerned about the spread of two other diseases currently active in Indonesia that affect livestock: lumpy skin disease and African swine fever. Last year, before the Indonesian foot-and-mouth outbreak had started, a group of experts led by Australia's chief veterinary officer, Dr. Mark Schipp, estimated there was a 42% probability that Australia would experience a major animal disease outbreak in the next five years. The risk for foot-and-mouth specifically was given a probability of 9%.
The government has since revised that guidance, having in June upped the probabiity of a foot-and-mouth outbreak in Australia to 11.6%, with a range of 3% to 20.5%.
At least one veterinarian suspects the probability of the disease reaching Australia could be higher. Dr. Ross Ainsworth, a practitioner based on the Indonesian island of Bali and consultant to the cattle industry, has seen firsthand how quickly the disease has taken root in Indonesia. "It's very widespread here," Ainsworth said, pegging the chance of foot-and-mouth reaching Australia at as high as 40%, while acknowledging, "That's just my gut feeling."
Ainsworth notes that Australian cities with large rural communities such as Darwin and Perth are only a three- or four-hour flight away. "Let's say you step in some virus — in some saliva or some manure or something — and it might last for two days on your shoe," he said. "That's enough time for you to get to Australia and to get near a farm. But if you're traveling to the U.K. or Europe, there's less chance it's going to make it all the way to a cow."
That doesn't mean contamination can't happen over long distances. The devastating outbreak that hit the U.K. in 2001 is widely believed to have originated from contaminated pig feed that had been illegally imported into the country. The strain of the virus responsible was found to be Type O, which is widely present in Asia. A subsequent outbreak in the U.K. in 2007 was quickly contained. Another recent outbreak of global significance occurred in Japan and Korea, in 2010 and 2011.
Additional factors are increasing the risk of an outbreak occurring in Australia, Ainsworth contends. For one, he notes the virus recently cropped up in Bali, a major tourist hub for Australians now holidaying in their droves following an easing of Covid-related travel restrictions. Tourists, he said, are more likely to interact with cattle in Indonesia than in many other places because villagers there tend to keep their animals in small groups and walk them out daily to and from grazing areas. Moreover, Indonesia, a relatively poor country with mixed standards of veterinary care, is struggling to control the outbreak.
When a country is confronted with foot-and-mouth, it typically can be managed either by "stamping out," which involves culling vulnerable animals en masse, or by vaccination. The disadvantage of the second option means losing the "without vaccination" status from the WOAH.
Indonesia, having so far vaccinated around 1.2 million animals and culled more than 8,000, hopes to regain its disease-free status by the end of the year, a government official said last week, though progress has been patchy and monitoring rudimentary: An ear-tagging system to identify vaccinated animals has only just started, Ainsworth said. "Here in Bali, they've been tying a red ribbon around the neck to identify a vaccinated animal — and then a cow eats the ribbon off another cow's neck."
By contrast, countries in which the disease is endemic, such as China, Thailand and Vietnam, routinely vaccinate animals and have more sophisticated and well-practiced case-identification, communication and quarantine protocols.
For his part, Pirbright's King doesn't expect Indonesia to rapidly gain control over the outbreak, increasing the risk of cross-border spread. "I think the pathway to regain FMD freedom is very challenging and may take some time," he said. "It appears that FMD is still spreading across the Indonesian islands, and that the current control measures are not limiting the spread of the disease."
Are veterinarians adequately prepared?
Photograph courtesy of the U.K. government
Blister-like sores on the mouth, including the lips and tongue, hooves and teats are a common clinical sign of foot-and-mouth disease in cattle, for which signs also can include fever, shivering, lameness, slobbering lips and the production of less milk, according to guidance from the U.K. government. Sheep and pigs don't display sores as commonly; lameness is the main clinical sign in those animals.
Since foot-and-mouth showed up in Bali, Australian authorities have installed detector dogs at Darwin and Cairns airports, a spokesperson for the country's department of agriculture confirmed. The dogs' work already has made international news headlines: In late July, a traveler from Bali was fined AUD$2,664 (US$1,887) after a detector dog sniffed out two beef sausage McMuffins and a ham croissant concealed in the passenger's backpack.
Other protective measures include enhancement of mail inspections, installation of footbaths and disinfectant mats at airports and additional signage and distribution of flyers informing travelers of their biosecurity responsibilities.
What the transmission risk means for veterinarians is being considered with particular urgency Down Under. The AVA, the country's chief representative body for the profession, is in talks with state and federal lawmakers to ascertain how veterinarians will fit into an outbreak response, its president, Dr. Bronwyn Orr, told the VIN News Service.
She'd like to see authorities draw up better preparation plans, including ensuring that there will be an adequate number of practitioners on hand to help with testing, monitoring, quarantining, culling and vaccination efforts, as needed. That could involve enlisting companion animal veterinarians, since the AVA fears there may not be enough government-employed and production animal veterinarians in private practice to take the strain.
"We just want to make sure that veterinarians aren't an afterthought," Orr said. "Obviously, government has been engaging extensively with producers and livestock sectors, which are very important and will be hugely affected by this. But we want to ensure that, if the time comes, we know that veterinarians are available, that they're trained and that they'll be fairly compensated."
In the event of a large foot-and-mouth outbreak, containment efforts likely would involve enlisting the help of veterinarians from overseas, too. Orr notes that during the U.K.'s outbreak in 2001, dozens of practitioners from Australia and New Zealand alone headed north to help.
Still, she'd like to see Australian veterinarians given precedence, with adequate compensation. "We would not be OK with a situation where, for whatever reason, government decides they don't want to pay market rates and instead, they're going to get overseas vets to come in and do this work."
More broadly, Orr said the foot-and-mouth crisis in Indonesia has highlighted what she sees as a lack of government investment in a veterinary sector that is suffering from labor shortages in regional and rural communities.
The AVA, she said, is pressing lawmakers to consider a range of policy initiatives that would assist the profession, including, for instance, offering student loan forgiveness to graduates that commit to working in rural areas for, say, three to five years.
"So, in the future, we won't need to wonder, 'Oh, will we have enough vets to respond to this disease outbreak?' " Orr said. "We will know because we will have a sustainable rural veterinary profession."
Correction: This article has been changed to remove a reference to pigs as ruminants. Although pigs are susceptible to foot-and-mouth disease like other cloven-hoofed animals, they are not ruminants.