title: Effects of freezing on the infectivity of toxoplasma gondii cysts for white mice.
abstract: The infectivity of Toxoplasma gondii cysts in the brains of mice, after storage at -21 degrees C for various periods of time, was studied by intraperitoneally inoculation into mice. Infective parasites were not demonstrated after freezing for 5 hours or longer. Even after 1 1/2 hours exposure to -21 degrees C, many cysts seemed to lose their infectivity. The role of low temperatures as a limiting factor in the epidemiology of cyst-induced toxoplasmosis, is discussed.
mesh_terms: D005516:Food Microbiology; D005615:Freezing; D006801:Humans; D008460:Meat; D008675:Metamorphosis, Biological; D013696:Temperature; D013997:Time Factors; D014122:Toxoplasma / Q000472:pathogenicity*; D014123:Toxoplasmosis / Q000517:prevention & control