By: Jared Timmons, James C. Cathey, Don Davis, Nikki Dictson, and Mark McFarland
Landowners in the Plum Creek Watershed of Hays, Caldwell, and Travis counties are battling feral hogs on their properties. They are upset about the destruction of crops, livestock pastures, wildlife habitat and degradation of water quality.
Many of them are also asking the question, do feral hogs have diseases that cause concern? The answer is yes. Three diseases that cause the most concern are swine brucellosis, psuedorabies, and tularemia, although, feral hogs harbor other diseases as well.
Swine brucellosis (Brucella suis), is a bacterium transmitted among feral hog populations through breeding (semen, reproductive fluids), and ingestion of the bacteria (placenta and aborted fetuses, milk and urine).
When humans contract swine brucellosis it is called undulant fever because body temperature rises and falls along with flu-like symptoms. In pigs, symptoms include abortions, lameness, arthritis, abscesses, infertility, and sometimes death.
Swine brucellosis is of concern to the cattle industry because this bacterium can cause a false positive test for bovine brucellosis (Brucella abortus). When a positive test for bovine brucellosis is found, the cattle herd is quarantined leaving the rancher with an economic loss.
Humans do not contract pseudorabies (Herpesvirus suis); however, domestic livestock like sheep, cattle and some wildlife can be affected. This disease is not a form of rabies as the name implies. Pseudorabies is spread by nose-to-nose or sexual contact, and ingestion or inhalation of the virus. Symptoms include abortion, mortality among piglets, coughing and fever among adults. Cattle and dogs experience intense itching and may incessantly scratch and bite at the skin. Other neurological symptoms may occur, and the endpoint is death.
Tularemia (Francisella tularensis) is commonly known as rabbit fever. Humans contract the disease by direct contact through a wound, eating infected meat, and by ticks and biting flies that harbor this disease. When humans contract tularemia, flu-like symptoms occur along with swollen lymph nodes. Severe cases can result in pneumonia, blood infections, or meningitis.
This bacterium can survive weeks in wet environments. Researchers at Texas Tech University tested 130 feral hogs and found that 50% of tested hogs in Crosby County and 15% in Bell and Coryell counties showed past exposure or were currently infected with tularemia.
Some diseases are transmitted in feral hog fecal material. This can be an issue when supplemental feed for livestock or wildlife is placed on the ground, increasing the chances of fecal contamination by hogs (Figure 1). Bacterial diseases such as swine brucellosis and tularemia are not generally spread this way, but other diseases such as salmonellosis, foot rot, intestinal bacteria, viruses, and parasites are commonly transmitted by this route.
Meat Processing and Handling
Hunters are also at risk for exposure to swine brucellosis, tularemia and other diseases. They should not process a feral hog that shows any signs of illness. To reduce chances of exposure, a double set of rubber or plastic gloves should be worn while processing and handling meat from feral hogs (Figure 2). Likewise, safety glasses should be worn to shield your eyes. Hands also should be washed often with soap and warm water, and tools and work surfaces cleaned with a dilute bleach solution.
Feral hogs make great table fare. However, always use a meat thermometer to ensure an internal temperature of 160°F has been reached and the meat is thoroughly cooked.
To hone your knowledge of feral hogs and reduction methods, several publications were developed by Texas AgriLife Extension Service and can be downloaded at no charge by going to the Plum Creek Watershed Partnership website at http://plumcreek.tamu.edu/feralhogs.
This website also has an on-line tool to report feral hog sightings or control measures, one report for cooperating landowners and another for the general public.
Download a printer-friendly version of this publication: Feral Hogs and Disease Concerns
Do you have a question -or- need to contact an expert?