Toxoplasma gondii infection in sentinel and free-range chickens from Argentina

MORÉ, G.; MAKSIMOV P.; PARDINI L.; HERRMANN, D.; BACIGALUPE, D.; MAKSIMOV, A.; BASSO, W.; CONRATHS, F.J.; SCHARES, G.; VENTURINI M.C.

Buenos Aires

Congreso; The 23rd International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP 2011); 2011

WAAVP

This study aimed at isolating and genotyping Toxoplasma gondii from serologically positive free-range chickens from Argentina, and to evaluate the use of sentinel animals during a short time period of exposure to determine environmental contamination with T. gondii oocysts. Two groups of chickens were used: I. 2-3 month-old broiler-type chickens reared as sentinel animals on the farms in two different seasons, and II. adult chickens reared on the same farms for more than one year. The sentinel animals (240 one-day-old chickens) and the food were donated to 5 farmers in Las Flores and one in La Plata. Seroconversion of 7.0% (8/114) and 5.7% (5/88) (with titers 100 and 200) was observed in sentinel broiler chickens reared for a period of 74 days (January ¨C April 2010) or 68 days (August ¨C November 2010) respectively, as shown by a T. gondii specific immunofluorescent antibody test. Fifty-three percent (17/32) of adult chickens were seropositive and showed higher titers than sentinel animals. Considering both sentinel study periods (summer-autumn; winter-spring), the monthly average seroconversion rate of free range chickens was approximately 3%. This suggests a widespread distribution of T. gondii oocysts in the environment which did not vary much over the year under study. Isolation of T. gondii from tissues (brain and heart) of serologically positive chickens was achieved from six of seven free-range adult birds (from 3 farms) with IFAT titres ¡Ý 200. The isolated parasites were analysed by multi-locus polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). T. gondii isolates corresponding to three different genotypes were obtained: two different genotypes consisted of atypical allele combinations (4 isolates), and the remaining genotype showed exclusively clonal type II alleles (2 isolates). On each farm, all the isolates obtained corresponded to the same genotype. These T. gondii genotypes were previously described in cats, dogs, chickens and capybaras elsewhere in South America. Our observations suggest that a greater diversity of T. gondii strains exists in Argentina than in North America and Europe.