Classical Swine Fever

Veterinary Services

January 2002

Still a Threat

Classical swine fever (CSF), also known as hog cholera, is a highly contagious viral disease of swine. CSF was eradicated from the United States in 1978 after a 16-year effort by the industry and State and Federal governments. Today, only 16 other countries are free of CSF. In the spring and summer of 1997, outbreaks of CSF were confirmed in Haiti and the Dominican Republic; both countries had eradicated the disease in the early 1980's. Also in 1997, several European countries, including the Netherlands and

Belgium, experienced outbreaks and suffered heavy losses. These outbreaks have animal health officials at the U.S. Department of Agriculture (USDA) concerned that CSF could spread to U.S. swine herds. While CSF does not cause foodborne illness in people, economic losses to pork producers would be severe if the disease were to become established again in this country.

Transmission

The most common method of transmission is direct contact between healthy swine and those infected with CSF. The disease can also be transmitted through contact with body secretions and excrement from infected animals. Healthy pigs coming into contact with contaminated vehicles, pens, feed, or clothing may contract the disease. Birds, flies, and humans can physically carry the virus from infected to healthy swine. Swine owners can inadvertently cause infection through feeding their herds untreated food wastes
containing infected pork scraps.

Signs

The clinical signs of CSF vary with the severity of the infection. There are three forms of the disease: acute, chronic, and mild.

The acute form of CSF is highly virulent, causing persistent fevers that can raise body temperatures as high as 107 °F. Other signs of the acute form include convulsions and lack of appetite. Affected pigs will pile or huddle up together. Signs of CSF may not be apparent for several days following infection. Death usually occurs within 5 to 14 days following the onset of illness.
The chronic form of CSF causes similar clinical signs in affected swine, but the signs are less severe than in the acute form. Discoloration of the abdominal skin and red splotches around the ears and extremities often occur. Pigs with chronic CSF can live for more than 100 days after the onset of infection.
The mild or clinically inapparent form of CSF seldom results in noticeable clinical signs. Affected pigs suffer short periods of illness often followed by periods of recovery. Eventually, a terminal relapse occurs. The mild strain may cause small litter size, stillbirths, and other reproductive failures. High mortality during weaning may also indicate the presence of this mild strain of CSF.

How Animal Health Officials Protect U.S. Animals

USDA's Animal and Plant Health Inspection Service (APHIS) maintains a constant vigil against the entry of foreign animal diseases, such as CSF.

To ensure pigs are free of disease, swine from countries affected by CSF can enter the United States only after a 90-day quarantine at a high-security import center in Key West, FL.

Control

APHIS coordinates an emergency task force made up of Federal, State, and local officials. This task force is ready to respond immediately to any foreign disease outbreak. If an outbreak of CSF should occur, the task force would take the following actions:

Investigate the affected farm to determine the history of illness, the types and number of pigs affected, and to collect any other information relating to the illness.
Quarantine the affected premises and the surrounding areas, if necessary, to restrict the movement of affected and exposed animals.
Trace all movements of swine to and from the affected premises.
Provide laboratory services to test affected and exposed animals.
Euthanize or slaughter and dispose of all infected and exposed animals; dispose of exposed materials like bedding and manure.
Supervise cleaning and disinfection of the affected premises.
Advise and assist area hog farmers if their herds are susceptible to the disease or located near a quarantined area.
Increase public awareness of the outbreak and control efforts through press conferences, news releases, and public service announcements.
Make available an onsite public information specialist to answer questions and provide updates to the media and the public.

How Swine Owners Can Protect Their Animals

Swine owners who suspect their pigs may have CSF should immediately contact their local veterinarian or Federal or State animal health official. Taking the following steps can help swine owners prevent this disease from becoming established in the United States:

Check animals at least twice a week for unusual signs or behaviors.
Make sure food waste is properly heated to destroy pathogens.
Isolate newly purchased hogs for at least 21 days.
Isolate sick pigs until the cause of illness is determined.
Fence property to prevent wild pigs from coming in contact with domestic herds.
Practice standard biosecurity measures, such as cleaning and disinfecting clothing, equipment, and vehicles entering and leaving the farm.

Report Suspicious Cases

Veterinarians and livestock owners who suspect an animal may have CSF or any other foreign animal disease should immediately contact State or Federal animal health authorities.

For more information, contact:
USDA, APHIS, Veterinary Services
Emergency Programs
4700 River Road, Unit 41
Riverdale, MD 20737–1231
Telephone (301) 734–8073
Fax (301) 734–7817

Current information on animal diseases and outbreaks is also available on the Internet. Point your Web browser to http://www.aphis.usda.gov to reach the APHIS home page.

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