First comprehensive histopathological and seroepidemiological investigations of Toxoplasma gondii infection in meat goats in Algeria.

Abstract

This study assessed Toxoplasma gondii infection in 92 slaughtered goats from four ecologically distinct regions of Algeria: Laghouat, Medea, Bouira, and Djelfa. Serological analysis was performed using a multispecies indirect ELISA, and histopathological examination targeted heart and diaphragm tissues to detect cysts or suggestive inflammatory lesions. The overall seroprevalence was low (4.3%), with no significant associations with age, sex, or breed. Geographic region significantly influenced seroprevalence: Bouira exhibited the highest rate (18.8%, p < 0.01), while other regions ranged from 0-8.3%. Histopathological analysis revealed a higher prevalence of lesions compatible with T. gondii (10.9%) in both heart and diaphragm. Young goats had higher lesion rates (18.8%) than adults (6.7%), though differences were not statistically significant. Regional differences were pronounced: Bouira showed 37.5% of animals with lesions (p < 0.001), El-Djelfa 16.7% (p < 0.04), while Laghouat remained free of lesions. These findings highlight a geographically clustered distribution of infection. Comparison of ELISA with histopathology indicated high concordance: 4 goats were positive across all methods, while 6 goats were ELISA-negative but tissue-positive, suggesting early, chronic, or low-antibody infections. Overall agreement between ELISA and tissue examination was 93.5%, with a Cohen's kappa of 0.54, indicating moderate to substantial agreement. The study demonstrates that intensive, closed-system goat farming effectively limits exposure to T. gondii, as evidenced by low seroprevalence and limited tissue infection. Importantly, combining serological and histopathological approaches provides a more comprehensive assessment of infection, capturing cases that may be missed by either technique alone. This dual diagnostic strategy enhances epidemiological understanding and improves surveillance, particularly in areas with environmental hotspots like Bouira.