Epidemiological investigation and phylogenetic analysis of Toxoplasma gondii strains from animal and human hosts as evidence of zoonotic spread in Duhok, Iraq

This study aimed to investigate the genetic diversity and transmission dynamics of Toxoplasma gondii strains isolated from animals and humans in Duhok Governorate, Iraq. A total of 15 strains originating from chickens, horses, sheep, and women with a history of abortion were analyzed using PCR amplification and sequencing of the ITS1 rDNA region. Phylogenetic analysis revealed all local strains clustered into a single, well-supported monophyletic clade, regardless of host species or geographic location, indicating a common ancestral origin. In contrast, global reference strains showed marked genetic divergence and did not cluster with the Duhok isolates. Although most Duhok strains appeared generalist, minor host-associated sub-clustering and unique branching patterns were observed. These findings underscore the importance of region-specific control strategies, including improved sanitation, safer animal management, and public education. The study advocates for a “One Health” approach, integrating human, veterinary, and environmental health efforts to monitor and mitigate the spread of T. gondii in endemic areas.