7Schulzig H S,,Fehlhaber K.Longitudinal study on the sero-prevalence of Toxoplasma gondiiinfectionin four German pigbreeding and raising farms. Berl Munch Tierarztl Wochen-schr . 2005
8Maria Cecilia Venturini Diana Bacigalupe Lucila Venturini Magdalena Rambeaud Walter Basso Juan M. Unzaga and Carlos J. Perfumo.Seroprevalence of Toxoplasma gondii in sows from slaughterhouses and in pigs from an indoor and an outdoor farm in Argentina. Veterinary Parasitology . 2004