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Dubey J.P.,U.S. Department of Agriculture | Rajendran C.,U.S. Department of Agriculture | Ferreira L.R.,U.S. Department of Agriculture | Martins J.,U.S. Department of Agriculture | And 6 more authors.
International Journal for Parasitology | Year: 2011

Little information is available concerning the presence of viable Toxoplasma gondii in tissues of goats worldwide. In the present study, hearts of 234 goats obtained from a local USA grocery store were examined for T. gondii infection. Blood clot or fluid removed from each heart was tested for antibodies to T. gondii by using the modified agglutination test (MAT). Antibodies to T. gondii were found in 125 (53.4%) of 234 goats, with titers of 1:5 in 20, 1:10 in 44, 1:20 in 16, 1:40 in five, 1:160 in five, 1:320 in five, and 1:640 or higher in 30. goats. Hearts of 112 goats (46 goats <1:5, and 66 goats 1:10 or higher) were used for isolation of viable T. gondii by bioassays in mice. For bioassays, 50. g of the myocardium were digested in an acid pepsin solution and the digest inoculated into mice; the recipient mice were examined for T. gondii infection. Toxoplasma gondii was isolated from 29 goats; from hearts of one of 46 with titers of <1:5, one of nine with titers of 1:10, one of three with titers of 1:40, and 26 of 40 with titers of 1:160 or higher. Two isolates were highly virulent to outbred Swiss Webster mice; all infected mice died of toxoplasmosis, irrespective of the dose. All T. gondii isolates were subsequently grown in cell cultures. Genotyping of the 29 T. gondii isolates using 10 PCR-restriction fragment length polymorphism markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) from DNA obtained from cell culture grown tachyzoites revealed 12 genotypes. Nine isolates were clonal Type II lineage, four isolates had type II alleles at all loci except a type I allele at the Apico locus, and four isolates were clonal Type III. The remaining 12 strains were divided into nine atypical genotypes, including five new and four previously identified genotypes. DNA sequences of four introns (EF1, HP2, UPRT1 and UPRT7) and two genes (GRA6 and GRA7) were generated for the five new genotypes. Comparing these sequences with previously published data revealed no unique sequences in these goat strains. Taken together, these results indicate high parasite prevalence and moderate genetic diversity of T. gondii in goats, which have important implications in public health. We believe this is the first genetic analysis of T. gondii isolates from goats in the USA. © 2011. Source


Alvarado-Esquivel C.,Mexico State University | Estrada-Malacon M.A.,Laboratorio Of Diagnostico Veterinario Of Valles Centrales | Reyes-Hernandez S.O.,Laboratorio Of Diagnostico Veterinario Of Valles Centrales | Perez-Ramirez J.A.,Laboratorio Of Diagnostico Veterinario Of Valles Centrales | And 3 more authors.
Journal of Parasitology | Year: 2012

Pigs are important in the epidemiology of toxoplasmosis in North America. Seroprevalence of Toxoplasma gondii infection in 525 domestic pigs (337 backyard raised, 188 farm raised) in Oaxaca State, Mexico was determined using the modified agglutination test (MAT, cutoff 1:25). Antibodies to T. gondii were found in 58 (17.2%) of the 337 backyard pigs with MAT titers of 1:25 in 10, 1:50 in 12, 1:100 in 18, 1:200 in 6, 1:400 in 6, 1:800 in 3, and 1:1,600 in 3. Seropositive pigs were found in 39 (37.9%) of 103 homes in all 7 municipalities surveyed. Seroprevalence of T. gondii infection in backyard pigs varied with age, gender, geographic region, climate, and altitude. High seroprevalence was found in pigs ≥9-mo-old (40%), in females (40%), in pigs from the Istmo region (33.3%), and in those raised in a tropical climate (65%). Seroprevalence was higher (24.5%) in pigs raised at 100-660 m above sea level than in those at 20-60 m of altitude (14.2%). With respect to farm pigs, only 1 (0.5%, MAT titer 1:100) of 188 pigs from 5 farms was positive for anti-T. gondii antibodies. The results affirm that the management system (outdoor vs. indoor system with biosecurity) is a key factor in the epidemiology of porcine toxoplasmosis. Because there is no national system of determining the T. gondii infection status at the time of slaughter, precautions should be taken while handling pig carcasses, and all pork should be cooked thoroughly before human consumption. © American Society of Parasitologists 2012. Source


Alvarado-Esquivel C.,Mexico State University | Silva-Aguilar D.,Laboratory of Animal Pathology of Morelia | Villena I.,National Reference Center on Toxoplasmosis | Dubey J.P.,U.S. Department of Agriculture
Preventive Veterinary Medicine | Year: 2013

Toxoplasma gondii infection in sheep is of public health and economic importance. Seroprevalence of T. gondii infection and correlates were determined in 405 sheep from 7 farms in 4 geographical regions in Michoacán State, Mexico using the modified agglutination test (MAT). General sheep and environmental characteristics were obtained by a questionnaire. All sheep were raised in semi-extensive conditions in temperate climate. Antibodies to T. gondii were found in 121 (29.9%) of the 405 sheep with MAT titers of 1:25 in 46, 1:50 in 20, 1:100 in 7, 1:200 in 5, 1:400 in 7, 1:800 in 11, 1:1600 in 5, and 1:3200 or higher in 20. Seropositivity did not vary significantly with age, sex or breed. In contrast, seroprevalence varied among farms, geographic region, municipality, altitude, mean annual temperature, and mean annual rainfall. The median seroprevalence in farms was 32.6% (range 7.1-71.4%). Sheep raised in farms at ≥1900. m above sea level had a higher seroprevalence (44.1%) than those in farms at lower sea level (16.3%). Sheep raised in municipalities with ≤17.7. °C mean annual temperature had a higher seroprevalence (37.2%) than those in municipalities with higher mean annual temperature (14.1%). Sheep raised in a municipality with 600. mm of mean annual rainfall had a higher seroprevalence (71.4%) than municipalities with higher mean annual rainfall (29.1%). This is the first report on the seroprevalence and correlates of T. gondii infection in sheep in Michoacán State, Mexico. The role of environmental characteristics for T. gondii infection in sheep deserves further research. © 2013 Elsevier B.V. Source


Alvarado-Esquivel C.,Mexico State University | Rodriguez-Pea S.,Mexico State University | Villena I.,National Reference Center on Toxoplasmosis | Dubey J.P.,U.S. Department of Agriculture
Journal of Parasitology | Year: 2012

Abstract: The seroprevalence of Toxoplasma gondii infection in horses in Mexico is unknown. Therefore, antibodies to T. gondii were assessed in 495 horses in Durango State, Mexico, using the modified agglutination test (MAT). Horses were from 18 farms in 3 municipalities in the valley region of Durango State. Antibodies to T. gondii were found in 30 (6.1) of 495 horses, with MAT titers of 125 in 19, 150 in 6, and 1100 in 5. Seropositive horses were found in 8 (44.4) of 18 farms sampled in all 3 municipalities. Age, gender, and breed of horses did not influence significantly the seroprevalence of T. gondii infection. The seroprevalence in horses was higher in rural (7.8) versus urban (0) areas, and in larger herds (3064 horses, 7.8) versus smaller ones (328, 3.5). The seroprevalence was higher in stall fed (16.5) than in pastured horses (3.1). Results indicate that infected horses represent a potential source of T. gondii infection for humans in Mexico. This is the first report of T. gondii infection in horses in Mexico. © American Society of Parasitologists 2012. Source


Alvarado-Esquivel C.,Mexico State University | Silva-Aguilar D.,Laboratory of Animal Pathology of Morelia | Villena I.,National Reference Center on Toxoplasmosis | Dubey J.P.,U.S. Department of Agriculture
Journal of Parasitology | Year: 2013

Seroprevalence of Toxoplasma gondii infection in goats in Michoacán, Mexico, is largely unknown. Antibodies to T. gondii were determined in 341 dairy goats in Michoacán, Mexico, using the modified agglutination test. Goats were raised in 9 farms in 6 municipalities. Overall, antibodies to Toxoplasma were found in 52 (15.2%) of 341 goats, with titers of 1:25 in 16, 1:50 in 9, 1:100 in 4, 1:200 in 4, 1:400 in 4, 1:800 in 9, 1:1,600 in 3, and 1:3,200 or higher in 3. Seropositive goats were found in all 9 farms sampled, and seroprevalence varied significantly among farms (1.9-90%). Seroprevalence of T. gondii varied with age, municipality, altitude, and climate but not with breed. Increased seroprevalence was found in goats aged 13-24 and 49-86 mo old (25% and 22.9%, respectively). Goats raised in farms in a municipality with semi-warm humid climate at 1,700 m of altitude had the highest seroprevalence (62.1%). This is the first report of T. gondii infection in goats in Michoacán State, Mexico, and of an association of seropositivity to T. gondii and semi-warm humid climate. Results indicate that infected goats are likely an important source of infection with T. gondii in humans in Michoacán State. © 2013 American Society of Parasitologists. Source

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