Molecular Diagnosis of Toxoplasma gondii in Free-Range Chickens (Gallus gallus) Sold at Fairs in the Metropolitan Region of Macapá–AP (Brazil)

Abstract

The informal commercialization of free-range poultry in open markets poses potential food safety risks regarding zoonotic pathogens. This investigation molecularly and histopathologically screened for Toxoplasma gondii in 36 free-range chickens acquired from 12 prominent markets in metropolitan Macapá, Amapá State. Paired heart and brain tissue samples from each animal were processed via conventional PCR and conventional histology. The pathogen was detected in 72.2% (n = 26) of the sampled population, driven by a high prevalence of concomitant tissue infection (58.3%, n = 21) and isolated brain positivity (13.9%, n = 5). Conversely, 27.8% (n = 10) of the flock tested negative, and microscopic examination yielded no evident bradyzoites or associated lesions. Sequenced amplicons were integrated into a genetic distance tree, demonstrating high identity and minimum evolutionary distance when clustered with a prominent group of 98 reference sequences. Spatial analysis confirmed environmental dispersion, with positive tissues originating from birds sold in 91.6% of the investigated commercial sites. The widespread presence of T. gondii in these retail outlets highlights a substantial risk of infection for local consumers. Our findings stress the urgency of establishing sanitary policies tailored to traditional markets in Amapá to control meat contamination and safeguard public health.