Although Toxoplasmosis is not a common problem or on top on the public’s watch list it continues to nag the pork industry.
As part of a pork checkoff-funded research project, Sharon Patton with the University of Tennessee, compared prevalence of T. gondii in sows and market-weight pigs. The data came from the National Animal Health Monitoring System Swine 2000 surveys, with changes compared with similar NAHMS surveys from 1990 and 1995.
The NAHMS Swine 2000 survey represents 94 percent of U.S. swine herds, involving operations with 100 or more pigs. The survey covers 17 of the major pork-producing states.
Serum samples from 505 swine herds were analyzed for this comparison.
The prevalence of T. gondii dropped from 1990 to 2000 in U.S. sow herds. Market hogs showed a decline from 1995 to 2000. Presence in sows was significantly greater than in market hogs – sows were seven times more likely to be infected. Market hogs had less than 1 percent prevalence of T. gondii.
Twenty-five percent of the herds had at least one positive animal. Sow herds were 10 times more likely to have a positive animal than market hogs.
The study illustrates that the number of swine herds infected with T. gondii continues to decline. Patton says the reduction is likely a result of improved husbandry practices in the pork industry.
Because carcasses from breeding animals are used in further-processed products there’s little likelihood that they would transmit Toxoplasmosis to humans.