title: Molecular and biological characterization of Toxoplasma gondii isolates from free-range chickens from Guyana, South America, identified several unique and common parasite genotypes.
abstract: The prevalence of Toxoplasma gondii in free-ranging chickens (Gallus domesticus) 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 in 76 free-range chickens from Guyana, South America was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 50 (65.8%) of 76 chickens with titres of 1:5 in four, 1:10 in one, 1:20 in five, 1:40 in seven, 1:80 in six, 1:160 in eight, 1:320 in four, 1:640 or higher in 15. Hearts and brains of 26 chickens with titres of <1:5 were pooled in 5 batches and bioassayed in mice. Hearts and brains of 50 chickens with titres of 1:5 or higher were bioassayed in mice. Toxoplasma gondii was isolated by bioassay in mice from 35 chickens with MAT titres of 1:20 or higher. All mice inoculated with tissues of 30 infected chickens remained asymptomatic. Toxoplasma gondii isolates from 35 chickens were genotyped using 11 PCR-RFLP markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, a new SAG2, and Apico. A total of 9 genotypes were identified, with 5 genotypes (nos 1, 4, 5, 6 and 7) unique to Guyana, 2 genotypes (nos 2 and 3) previously identified in chickens from Brazil, 1 genotype (no. 8) previously identified in chickens from Brazil, Costa Rica and Nicaragua, and 1 genotype (no. 9) belonging to the clonal type III lineage that exists globally. Infection with 2 genotypes was found from 1 chicken. This is the first report of genetic characterization of T. gondii isolates from any host from Guyana.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA. jdubey@anri.barc.usda.gov
authors.forename: J P
authors.initials: JP
authors.lastname: Dubey
authors.forename: L
authors.initials: L
authors.lastname: Applewhaite
authors.forename: N
authors.initials: N
authors.lastname: Sundar
authors.forename: G V
authors.initials: GV
authors.lastname: Velmurugan
authors.forename: L A
authors.initials: LA
authors.lastname: Bandini
authors.forename: O C H
authors.initials: OC
authors.lastname: Kwok
authors.forename: R
authors.initials: R
authors.lastname: Hill
authors.forename: C
authors.initials: C
authors.lastname: Su
mesh_terms: D000372:Agglutination Tests; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001681:Biological Assay; D001921:Brain / Q000469:parasitology; D002645:Chickens / Q000469:parasitology*; D017125:Genes, Protozoan / Q000235:genetics*; D005838:Genotype; D005843:Geography; D006172:Guyana; D006321:Heart / Q000469:parasitology; D051379:Mice; D011201:Poultry Diseases / Q000469:parasitology*; D014122:Toxoplasma / Q000235:genetics* / Q000302:isolation & purification*; D014124:Toxoplasmosis, Animal / Q000469:parasitology*
chemical_list: D000913:Antibodies, Protozoan