Action of table salt on Toxoplasma gondii

Abstract

Results of our inquiry on Toxoplasma gondii frequency in pork sausages from Erechim (RS, Brazil), where the incidence of toxoplasmotic chorioretinitis is high (9% according SILVEIRA, 1987)9, revealed only one isolation of the parasite among 40 sausage samples. (MARTINS, 1989)5,6. The sausages were prepared with pork and common table salt, and were ingested, frequently, in raw stale, during its preparation. In this experiment, table salt action on tachyzoites and cysts of Toxoplasma gondii, was investigated. Albino male mice were intraperitoneally inoculated with 0,5 ml of peritoneal exsudates (tachyzoites) or brain macerates (cysts) from previously infected mice. Some strains were isolated from pork and pork sausages from Erechim. Refined common table salt was added to the inocula at 2,2%, 2,5% and 3,0% concentrations, during 24 and 48 hours, 3-5 and 7 days of exposition time, at 4º C. The results demonstrated that at 2,2%, 2,5% and 3,0% salt concentrations and 24 and 48 hours of time exposition all mice inoculated with tachyzoites were dead, except one, probably not infected. At 3,0% and 3-5 and 7 days of contact, 10 in 37 inoculated mice survived (27%). Of the mice inoculated with cysts plus salt at 3,0%, at 5 and 7 days exposition, 85%; survived (17 in 20). All the controls mice inoculated with the same inocula without salt, at the same conditions, died earlier than the test mice. The Toxoplasma was recovered from peritoneal exsudates and brains of recently dead and diyng mice, but not from the survivors. Conclusion: the table salt has an inactive action on Toxoplasma gondii in 3,0% concentration and at 3 to 7 days exposition. Possibly this may explain the rare isolation of the parasite in pork sausages of Erechim inquiry.