Scientists from around the world came to Kansas State University’s Biosecurity Research Institute (BRI) May 15-17 to take a global look at the highly contagious viral disease, African swine fever (ASF). The researchers assembled to give updates on research and in some cases, the status of ASF in their countries.
ASF has not been found in the United States, but is a serious problem in Africa and outbreaks have occurred in other countries, including Spain, Italy, Russia and the Dominican Republic. There is no vaccine or treatment. Changes in production practices and increasing globalization have increased the risk of introducing ASF into North America and other parts of the world, according to the Center for Food Security and Public Health at Iowa State University.
“ASF is spreading in many areas of the world which means that there is an increasing threat of introduction into the United States,” says Stephen Higgs, research director of the BRI and symposium coordinator. “Something as simple as a discarded sandwich containing meat from an infected pig could be enough to cause an outbreak. Although we might be able to contain an outbreak in commercial pigs, the consequences could be devastating to our booming and highly competitive pork industry. Due to the growing numbers of feral swine that are widely distributed in the United States, the virus could then become established here.”
Humans are not susceptible to the African swine fever virus (ASFV), but when an outbreak occurs in any region or country, the financial and physical implications can be devastating to the swine industry and those related to it. During outbreaks in Malta and the Dominican Republic, for example, the swine herds of the entire countries were completely depopulated.
The effect on a swine herd can vary depending on the strain, from near 100% mortality to cases of low virulence isolates that can be difficult to diagnose.
Species that can be infected include domesticated members of the pig family, as well as wild species, such as wild boars, warthogs and bush pigs, the latter species usually without clinical signs.
“We have 20 million feral pigs in Australia, so if African swine fever arrives, we might have a problem we could never get rid of,” says Martyn Jeggo, director of the Australian Animal Health Laboratory. He said Australia has a commercial swine herd of about 2.5 million head.
ASF can be transmitted by direct contact with infected animals, ticks, or indirect contact with fomites – inanimate objects or substances such as clothing, furniture or soap – that are capable of transmitting infectious organisms from one individual to another. Other blood-sucking insects such as mosquitoes and biting flies may also be able to mechanically transmit the virus.
With the economic, physical and emotional toll of the foot-and-mouth disease (FMD) outbreak in the United Kingdom (UK) during 2001 still fresh, John Fazakerley, director of the Institute of Animal Health in Pirbright, UK says, “The country wants the capacity to deal with whatever comes along.” Estimated costs of the FMD outbreak ranged from $8 billion to $13 billion, and 6.5 million animals were slaughtered.
“The emergence of African swine fever virus (ASFV) in the Republic of Georgia, followed by further spread throughout Russia, establishes this pathogen as a high-threat pathogen for the United States,” says Juergen Richt, director of the Department of Homeland Security Center of Excellence for Emerging and Zoonotic Animal Diseases headquartered at Kansas State University (KSU). For that reason, KSU, in collaboration with national and international partners, is planning to conduct research on the virus.
“Our short term plans include adaptation and validation of the ASFV challenge model developed by our colleagues at the Plum Island Animal Disease Center,” Richt says. The model will establish a baseline for future vaccine studies.
Richard Bishop, senior molecular biologist with the International Livestock Research Institute in Nairobi, Kenya spoke of the importance of the swine herd in Africa, adding that even one pig can make a significant difference in a family’s income. He said that the pig population in Africa increased 284% from 1980 to 1999 and that pork consumption during the period almost doubled.
ASF is currently a problem in Russia, but scientists are facing challenges in combating the disease.
“It’s difficult to explain to authorities that this is very important,” says Denis Kolbasov, director of the National Institute of Veterinary Virology and Microbiology in Vladimir, Russia. “The cost of control is an impediment,” he says, adding that because Russia does not export pork, ASF is not considered a trade issue.
Scientists from Spain, Kenya, Canada, Ukraine and several U.S. states also participated in the symposium.
More information on African swine fever is available at: www.cfsph.iastate.edu/Factsheets/pdfs/african_swine_fever.pdf .