Experimental toxoplasmosis in house sparrows (Passer domesticus)

A total of 31 house sparrows (Passer domesticus) were divided into five groups of six to seven birds. Birds were infected per os with 1, 10, 102, 103 and 104 oocysts of Toxoplasma gondii of the K1 strain, respectively. When the general health, production of antibodies against T. gondii and isolation positivity of the sparrows were examined in weeks 3, 7 and 12 post-infection (p.i.), no clinical signs of toxoplasmosis were observed. Seroprevalences ascertained in weeks 3, 7, and 12 p.i. were 64% (18 positive/28 tested), 95% (21/22) and 70% (7/10) when tested by indirect immunofluorescence (titre 20); 54% (15/28), 59% (13/22) and 70% (7/10) when tested by the latex agglutination test (titre 20); and 59% (4/7), 0% (0/12) and 20% (2/10) when tested by the Sabin Feldman dye test (titre 4), respectively. T. gondii was re-isolated from 45% (13/29) infected sparrows. House sparrows were found to exhibit some resistance to the K1 strain of T. gondii after oocyst infection, and the results suggest that sparrows may not be a significant source of environmental infection.