Spread of African Swine Fever Raises Global Concerns
Mar 18, 2019
African Swine Fever (ASF) was identified as a distinct disease in the 1920’s. It was first found in Kenya during that period. Prior to that determination, such outbreaks had been believed to have resulted from classic swine fever brought to the continent by European settlers. The two viruses are unrelated, but their lethality to swine is similar--both highly devastating, with mortality approaching 90 to 100 percent in many instances. This virus does not affect humans, but presents a significant risk to global livestock industry
Over the last century, this highly contagious disease which affects the circulatory system of swine and related wild animals has become endemic in much of Africa. A reservoir of the virus usually persists among the wild relatives (warthogs and tampans) which inhabit the savannahs in much of the continent, making it much more difficult to eradicate. The virus can also be transmitted by certain species of ticks, which can attach themselves to non-targeted species and spread over long distances under the right circumstances.
ASF made its initial foray outside of Africa in the Caribbean region in the late 1970’s and in Spain and Portugal in the mid-1990’s, but those countries were successful in eradicating the disease. Until 2018, the only place outside of Africa that was ASF-endemic was the island of Sardinia, off the coast of Italy in the Mediterranean Sea.
In early August of 2018, the government of China announced that cases of ASF had been detected in three widely dispersed regions of the country, forcing them to depopulate thousands of animals to try to stem the outbreak. In 2018, China was estimated to have more than 700 million hogs, the largest pork-producing country in the world, more than half of which were raised on small family farms with likely inadequate biosafety controls.
Within two months, the ASF outbreak in China had spread to more than 30 cities, despite bans imposed on transporting pigs from provinces with reported cases by the central government when the outbreak was first announced. While the government of China had lifted the transportation ban in most affected regions by early February, new cases continue to be reported. In their place, the government is trying to limit spread of the virus by requiring that slaughterhouses separate out pigs from different provinces of origin, and can only market the products if the blood from a given batch of slaughtered pigs test negative for ASF virus. The government is also trying to ban hog farmers from feeding kitchen waste to their animals, fearing that the virus is being transmitted via this route as well. By early March, at least 950,000 pigs had been destroyed due to the outbreak in China, according to data reported to the UN’s Food and Agriculture Organization (FAO).
In mid-February, the first cases of ASF were detected in Vietnam, almost certainly having arrived by either live animals or pork products shipped from China. The country is estimated to have around 30 million hogs, raised primarily on family farms rather than in confined feeding facilities.
In recent years, a handful of cases have been reported in the European Union, primarily in the Baltic states as well as Poland and Romania. The September 2018 detection of ASF cases in Belgium generated significant concern, because the disease had not been found in Western Europe since the 1990’s cases on the Iberian Peninsula. EU authorities suspect the virus may have arrived in frozen pork product--where it can survive for up to three months--since few live animals are shipped between eastern and western Europe.
To date, no confirmed case of ASF has been detected in the United States, but its relatively rapid spread in both Europe and Asia in recent months has both the U.S. hog sector and relevant U.S. government officials on alert. The U.S. Department of Agriculture is working with its counterparts in our neighboring countries, Canada and Mexico, to strengthen the procedures to keep potentially infected pork product out of this country. On March 12th, the Under Secretary of Agriculture for Marketing and Regulatory Affairs, Mr. Greg Ibach, announced that they would increase by one-third the number of human/beagle teams stationed at U.S. commercial ports, and try to raise the awareness of the general public to the importance of abiding by U.S. quarantine laws.
Just last week, on March 15th, the U.S. Customs and Border Protection Agency announced that they had seized an illegal shipment of about 1 million pounds of pork that was in bound from China. The smuggled shipment was found in shipping containers held in a warehouse in New Jersey.
It is estimated that a widespread outbreak of ASF in the United States could cause the hog sector more than $10 billion in damages in just the first year. There is currently no vaccine against ASF, but scientists working in national agricultural research systems in several countries, including the United States and China, are now working to develop one. Interestingly, a major effort at USDA’s Agricultural Research Service working on this matter at USDA’s Plum Island foreign agricultural disease research facility was initiated on September 1, 2018, less than one month after the first ASF case was detected in China.