National Hog Farmer
Feral Swine Surveillance Focuses on Classical Swine Fever

Feral Swine Surveillance Focuses on Classical Swine Fever

USDA's Animal and Plant Health Inspection Service  conducts regular testing to monitor the disease risks posed by feral swine. Of primary concern is the possibility that feral swine populations may carry classical swine fever (CSF), also known as hog cholera.


Feral swine represent another food security issue addressed in part by USDA’s Animal and Plant Health Inspection Service (APHIS) classical swine fever (CSF) surveillance program, according to David Pyburn, DVM, Swine Health Programs, APHIS, Des Moines, IA. The CSF program began in 2006.

Each year, from 2,500 to 4,000 mostly blood samples are collected by APHIS’ Wildlife Services while trapping or hunting feral pigs to thin out the population, Pyburn explains. Testing helps ensure that CSF, or hog cholera as it was known during the eradication campaign that was successfully completed in 1978, hasn’t found its way back into the United States, he adds.

 “CSF still exists in neighboring Mexico, and the adjacent states of California and Texas, plus Florida and North Carolina, comprise the areas of highest risk due to larger feral pig populations and because of the way that pigs are raised in those areas,” Pyburn says.

The proximity of feral swine to outdoor-raised swine in those states heightens the security risk. Wildlife Services also harvests more feral swine from those states, enhancing the probability of detection.

“The point of the CSF surveillance program is we have not had this disease within our borders since before 1978 and we want to keep it that way. If it should come back, the CSF surveillance program is set up in such a way that we would be trying to find it just as quick as we can, stamp it out just as quick as we can and at as low a cost as we can,”
Pyburn points out.

Educational videos on CSF produced in partnership with the Center for Food Security and Public Health at Iowa State University (, the National Pork Board ( and the American Association of Swine Veterinarians ( are available from those sources. For veterinarians who are not members of the AASV, contact Pyburn at for videos.

Pseudorabies (PRV) and swine brucellosis have been eradicated from the commercial swine population of the United States. But those diseases are thought to be endemic in feral swine, so testing is not normally pursued, except when feral swine are traced to a new area. A few years ago, feral swine moving from Missouri to southern Iowa were tested as a new population.

“We want all of our producers to assume the worst and keep them (feral swine) separate from their domestic swine, as even in the Midwest they represent a concern for brucellosis, but especially for PRV,” he stresses.  

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