Tissue distribution and molecular characterization of chicken isolates of Toxoplasma gondii from Peru.

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii antibodies in sera of 50 free-range chickens (Gallus domesticus) from Peru was 26% on the basis of the modified agglutination test (MAT). Hearts, pectoral muscles, and brains of seropositive (MAT > or =1:5) chickens were bioassayed individually in mice. Tissues from the remaining 37 seronegative chickens were pooled and fed to 2 T. gondii-free cats. Feces of cats were examined for oocysts; they did not shed oocysts. Toxoplasma gondii was isolated from the hearts of 10 seropositive chickens but not from their brains and pectoral muscles. Genotyping of these isolates using the SAG2 locus indicated that 7 isolates were type I and 3 were type III. Six of the 7 type-I isolates were avirulent for mice, which was unusual because type-I isolates are considered virulent for mice. The T. gondii isolates were from chickens from different properties that were at least 200 m apart. Thus, each isolate is likely to be different. This is the first report of isolation of T. gondii from chickens from Peru.

Toxoplasma gondii infections in cats from Paraná, Brazil: seroprevalence, tissue distribution, and biologic and genetic characterization of isolates.

Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete environmentally resistant oocysts. The prevalence of T. gondii was determined in 58 domestic cats from 51 homes from Santa Isabel do Ivai, Parana State, Brazil where a water-associated outbreak of acute toxoplasmosis had occurred in humans. Antibodies to T. gondii were found with the modified agglutination test in 49 of 58 (84.4%) cats at a serum dilution of 1:20. Tissues (brain, heart, and skeletal muscle) of 54 of these cats were bioassayed in T. gondii-free, laboratory-reared cats; T. gondii oocysts were excreted by 33 cats that were fed feline tissues. Brains from these 54 cats were bioassayed in mice; T. gondii was isolated from 7. Skeletal muscles and hearts of 15 cats were also bioassayed in mice; T. gondii was isolated from skeletal muscles of 9 and hearts of 13. The results indicate that T. gondii localizes in muscle tissue more than the brains of cats. In total there were 37 T. gondii isolates from 54 cats. Most isolates of T. gondii were virulent for mice. Genotyping of the 37 isolates of T. gondii, using the SAG2 locus, revealed that 15 isolates were type I and 22 were type III. The absence of type II genotype in cats in this study is consistent with the previous studies on T. gondii isolates from Brazil and is noteworthy because most T. gondii isolates from the United States are type II. These findings support the view that Brazilian and North American T. gondii isolates are genetically distinct. This is the first report of genotyping of T. gondii isolates from the domestic cat.

Isolation and genotyping of Toxoplasma gondii from free-ranging chickens from Argentina.

The prevalence of Toxoplasma gondii in free-ranging chickens can be considered a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 29 free-range chickens (Gallus domesticus) from Argentina was investigated. Blood, heart, and brain from each chicken were examined for T. gondii infection. Antibodies to T. gondii, assayed with the modified agglutination test (MAT), were found in 19 of 29 (65.5%) chickens. Hearts and brains of seropositive (MAT > or = 1:5) chickens were bioassayed in mice. Toxoplasma gondii was isolated from 9 of 19 seropositive chickens. Genotyping of chicken isolates of T. gondii using the SAG2 locus indicated that 1 was type I, 1 was type II, and 7 were type III. This is the first report of isolation of T. gondii from chickens from Argentina.

Characterization of Toxoplasma gondii isolates from free range chickens from Paraná, Brazil.

The prevalence of Toxoplasma gondii in free range chickens is a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 40 free range chickens (Gallus domesticus) from a rural area surrounding Paraná, Brazil was assessed. Blood, heart, and brain from each chicken were examined for T. gondii infection. Antibodies to T. gondii, assayed with the modified agglutination test (MAT> or =1:5) were found in 16 chickens. Hearts and brains of seropositive (MAT> or =1:5) chickens were bioassayed in mice. Additionally, hearts and brains of seronegative (MAT<1:5) chickens were bioassayed in two T. gondii-free cats (12 chickens per cat). T. gondii was isolated from 13 of 16 (81%) seropositive chickens. Of the two cats fed tissues pooled form seronegative chickens, one shed T. gondii oocysts. Nine of the 13 T. gondii isolates killed 100% of infected mice. The T. gondii isolate from the cat was also virulent for mice. Genotyping of 13 chicken isolates of T. gondii using the SAG2 locus indicated that seven isolates were type I and six were type III; three of these type III isolates killed all infected mice suggesting that all strains virulent for mice are not type I. The isolate from the feces of the cat fed chicken tissues was type I.