Toxoplasma gondii levels in swine operations: differences due to technology choice and impact on costs of production

Abstract

Serum samples were collected from 3236 sows and 4712 market hogs in 1995. Sera were collected from sows on 226 farms, while market hog sera was obtained from 282 farms. Herds were randomly selected to participate in the 1995 National Animal Health Monitoring System (NAHMS) swine survey. Serawere assayed for antibodies against Toxoplasma gondii using the modified direct agglutination test. Herd data and serologic information were used to study the association between T. gondii infection in sows and specific herd characteristics and farm management practices. Overall, 15.1 percent ofsows and 3.2 percent offinishers were positive for toxoplasmosis. Analysis ofthe data showed significant associations between toxoplasmosis in sows or herds and three factors: 1) method of rodent control, 2)type of production facility, and 3) access of cats to production facilities. In particular, seronegativity was associated with the use of bait and/or traps only" for rodent control as compared to the use of cats for rodent control. Thus, use ofcats as a method ofrodent control should be avoided by producers. No regional differences in prevalence were detected and toxoplasmosis in sows was not associated with a reduced level of reproductive performance. were randomly selected to participate in the 1995 National Animal Health Monitoring System (NAHMS) swine survey. Serawere assayed for antibodies against Toxoplasma gondii using the modified direct agglutination test. Herd data and serologic information were used to study the association between T. gondii infection in sows and specific herd characteristics and farm management practices. Overall, 15.1 percent of sows and 3.2 percent of finishers were positive for toxoplasmosis. Analysis ofthe data showed significant associations between toxoplasmosis in sows or herds and three factors: 1) method ofrodent control, 2) type of production facility, and 3) access of cats to production facilities. In particular, seronegativity was associated with the use of bait and/or traps only" for rodent control as compared to the use of cats for rodent control.Thus, use ofcats as a method of rodent control should be avoided by producers. No regional differences in prevalence were detected and toxoplasmosis in sows was not associated with a reduced level of reproductive performance.

Pathogens of Interest to the Pork Industry: A Review of Research on Interventions to Assure Food Safety

“…Thus, outdoor cats on farms which scavenge other animals are a major concern for spreading T. gondii to swine. Sows were 14.3% more likely to be infected with the parasite when cats were present (Wang and others ).…”

“…Animal Health Monitoring Survey (NAHMS) was conducted in 2006 for swine and revealed a 2.6% seroprevalence of T. gondii in pigs from 16 of the leading swine production states in the United States (Hill and others ). T. gondii prevalence at the farm is highly dependent on production stage and management practices, with a higher prevalence in breeding swine than market swine (Dubey and others ; Wang and others ). Prevalence in breeding swine can be decreased with management practice.…”

“…Prevalence in breeding swine can be decreased with management practice. Lower sow prevalence of T. gondii has been associated with larger herd size and indoor confinement (Wang and others ). Sow prevalence in the United States decreased from 20% in 1990 to 6.5% in 2000, likely due to the switch to indoor confinement and increased biosecurity measures (Hill and others ).…”

“…Cats on the farm put swine at the highest risk for T. gondii because felines are the only known shedders of the cysts (Wang and others ; García‐Bocanegra and others ; Hill and others ). Cats become infected by consumption of contaminated rodents, wildlife, meat, soil, or water.…”

“…Despite the advances in vaccination use in cats, management practices for controlling cross‐contamination from cats or other animals to swine is probably more realistic and economical. Various researchers determined that farms where swine were totally confined and cats were not present had a significantly lower prevalence of T. gondii (Wang and others ; García‐Bocanegra and others ). Additional farm management techniques, including heating of feed to destroy the pathogen and ensuring clean drinking water is provided, also reduce prevalence of the parasite (Mateus‐Pinilla and others ).…”