Molecular detection of Chlamydia psittaci in wild birds, broiler chickens, and sheep in Egypt: a public health concern

Chlamydia psittaci is a neglected pathogen of global concern, characterized by significant zoonotic and spillover potential, posing considerable risks to public health. This study aimed to investigate the prevalence of C. psittaci in broiler chickens, wild resident birds, and sheep in Egypt using molecular detection and sequence analysis to explore possible zoonotic relevance. A total of 230 oropharyngeal swabs were collected from apparently healthy animals, including broiler chickens (n = 100), resident wild birds (n = 80; hooded crows n = 20, cattle egrets n = 20, rock pigeons n = 20, and laughing doves n = 20), and sheep (n = 50). Genomic DNA was extracted and screened using PCR targeting the Chlamydia genus-specific 16S rRNA gene. Species identification of C. psittaci was confirmed by amplification of the ompA gene. Moreover, sequencing and phylogenetic analysis of the ompA gene were performed. The overall prevalence of C. psittaci was 3.5% (8/230). Positive samples were identified in broiler chickens (5/100; 5%), hooded crows (1/20; 5%), rock pigeons (1/20; 5%), and sheep (1/50; 2%), while cattle egrets and laughing doves tested negative. Phylogenetic analysis of the ompA gene sequence showed close clustering with previously reported C. psittaci strains from seabirds, confirming a strong genetic relationship. The detection of C. psittaci in broiler chicken, wild birds, and sheep within the same geographic area highlights the potential circulation of this pathogen among multiple host species. These findings emphasize the importance of developing targeted surveillance systems and implementing One Health control strategies.