Prevalence and genetic characterization of Toxoplasma gondii in free-range chickens from grocery stores and farms in Maryland, Ohio and Massachusetts, USA

Abstract

Chickens are considered important in the epidemiology of Toxoplasma gondii. Chicken hearts (n = 1185) obtained from grocery stores were tested for T. gondii infection. Antibodies to T. gondii were assayed in fluid removed from the heart cavity using the modified agglutination test (MAT) at 1:5, 1:25, and 1:100 dilutions. MAT antibodies were detected in 222 hearts at 1:5 dilution and 8 hearts at 1:25 dilution, but none were positive at 1:100 dilution. Seropositive (n = 230, 19.4%) chicken hearts were bioassayed in mice and seronegative (n = 157) chickens were bioassayed in cats. Viable T. gondii was not isolated from any hearts by bioassays in mice. The 2 cats fed 60 and 97 hearts did not excrete T. gondii oocysts. The results indicate a low prevalence of viable T. gondii in chickens from grocery stores. Molecular typing of 23 archived T. gondii strains isolated from free-range chickens from Ohio and Massachusetts using the 10 PCR-RFLP markers including SAG1, SAG2 (5'-3'SAG2 and altSAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico revealed that seven were ToxoDB PCR-RFLP genotype #1, 11 were genotype #2, one was genotype #3, three were genotype #170, and one was mixed genotype. These results indicate that the clonal genotypes #1 (type II), #2 (type III), and #3 (type II variant) are common in free-range chickens.

Prevalence and Haplotypes of Toxoplasma gondii in Native Village Chickens and Pigs in Peninsular Malaysia

“…Phylogenetic analysis of T. gondii sequences from this study was clustered together with isolates from other studies ( Figure 2 and Figure 3 ). This indicates close genetic relatedness of the isolates, which corroborates previous reports on chickens from the USA [ 54 ] and cats from China [ 55 ]. According to Bontell et al [ 56 ], sexual recombinants of T. gondii in cats are rare in nature, as transmissions commonly occur through carnivorism and scavenging.…”

Prevalence and molecular characterization of Toxoplasma gondii in different types of poultry in Greece, associated risk factors and co-existence with Eimeria spp.

“…It seems plausible that prolonged contact with the ground or litter as well as access to the outdoor area including free-grazing practices typically seen in organic and free-range chicken farming, increases the likelihood of T. gondii infection. As the demand for slow-growth and/or free-range chicken meat keeps increasing (Ying et al 2017), special attention should be paid to T. gondii infections to reduce potential transmission to humans from undercooked meat or other raw preparations like chicken sausages or carpaccio where there might not be sufficient inactivation of the parasite (Schares et al 2018). The majority of published studies referring to free-range chickens include both commercial and hobby/backyard farms, with a range of seroprevalence from 6.6% to 90% (Asgari et al 2009;Cui et al 2010;Zhao et al 2012;Moré et al 2012;Chumpolbanchorn et al2013;Hamidinejat et al 2014;Gebremedhin et al 2014;Magalhães et al 2016;Vismarra et al 2016;Wang et al 2016;ElFadaly et al 2017;Rodrigues et al 2019;Dubey et al 2020).…”

Toxoplasma gondii in Foods: Prevalence, Control, and Safety

“…In China, Japan, and the USA, recent studies indicated a 10–20% infection rate of quick-frozen chickens [ 85 , 130 , 160 ]. In India, the chicken tissue prevalence is 2.3% and the seroprevalence is around 6.5% [ 130 ], whereas in Brazil the seroprevalence is around 36% [ 128 ]. T. gondii infection may be accompanied by infection from other pathogens of chickens, as Eimeria tenella [ 161 ].…”