A unique kind of swine fever is spreading rapidly though China.
The UN Food and Agricultural Organization (FAO) reports a severe outbreak of a disease called African Swine Fever, or ASF, that may cross Chinese borders and spread throughout Asia. So far, thousands have domestic pigs have been culled to slow the spread of the disease.
This could be an economic disaster. There are about 500 million pigs in China — it produces about half the world’s pork. And ASF is spreading fast. It’s already been detected in regions 1000 miles apart. There is no vaccine for ASF, and it’s almost 100% fatal in domestic pigs. Outbreaks are stopped by rapidly culling infected pigs, and applying rigorous hygiene and biosafety measures.
To date Chinese authorities have culled 24,000 pigs. The real fear here is not just China – if ASF could move this fast across China, it could also move into Korea and Southeast Asia.
African Swine Flu doesn’t infect people, so the harm it causes to humans is economic rather than medical. Still, the scary thing about African swine fever is that its spread is not restricted to live pigs. It can also be spread through food like pork meat, and even cured pork products. Think: contagious bacon. Outbreaks often start when pigs get into garbage left where they can eat it. Or, in at least one example, when a tourist shared food with a wild boar, triggering an outbreak that led to twelve herds being culled.
This is the first time that African swine fever has been reported in China.
The source of the initial outbreak is unknown, but the most likely cause is an infected pork product being brought across the border from Russia and discarded where domestic pigs could scavenge it. The disease has been prevalent in Russia for decades, as well as in Eastern Europe and Sardinia; 100,000 pigs have been culled in Romania this year because of ASF. In addition to the risks of pork products, the ASF virus lingers on surfaces, and can survive in very hot or very cold weather. This means the disease can be transmitted through the trucks used to transport swine, or even on shoes or farm equipment.
This is not the only disease that spreads among animals with human help. Hoof and mouth disease which infects pigs and cattle, but not humans, is an ongoing threat to European and British farming. It’s spread by infected meat products, and originally arrived in the UK from Asia because of improperly discarded food waste. Any time large numbers of animals are kept in close quarters, there is a risk of disease. Minor failures in hygiene or quarantine can lead to rapid outbreaks.
ASF is endemic and largely symptomless among wild pigs in Africa. In domestic swine that have been bred for food, however, it causes fatal hemorrhaging. And, of course, as more wild land is turned into farmland, more wild pigs are forced into contact with domestic animals. It was first identified when European settlers brought domestic swine to Africa in the early 20th century, but virus research indicates the disease probably evolved in the 1700s.
FAO is now working closely with governments in Asia to ramp up biosecurity efforts and contain the virus. They have activated a regional ASF contingency plan, and are training veterinarians in the region. Beijing has asked farmers to stop transporting live hogs from high risk areas. Chinese authorities, however, don’t sound optimistic. The Ministry of Agriculture and Rural Affairs issued a statement that, “We cannot rule out the possibility of new African swine fever outbreaks,” going on to state that neighboring countries have been infected with the disease for a long time.
The evolving economic catastrophe of Africa Swine Fever is reminder of why international health regulations, and institutions, exist. Rapid detection of ASF infections, good biosafety techniques in farms and at borders, and close cooperation among regions and nations will be required to keep ASF contained. Detection, biosafety, cooperation – they’re the same tools that are being used against Ebola in Congo right now, and against Zika virus in Brazil. When governments stop taking those tools seriously, epidemics get the chance to spread.