RESUMEN
The members of the Chlamydiaceae family are important pathogens that infect a wide range of vertebrate hosts, including humans. Among them, Chlamydia psittaci, historically considered as an avian agent, has recently been identified in livestock, primarily sheep and cattle, but also in horses, with the infection being linked to reproductive disorders, such as abortion, absorption of embryos, stillbirth, and the birth of weak foals. Much less is known about chlamydial infections in the Sardinian equine population. This study aimed to identify the chlamydial diversity in genital samples from asymptomatic Sardinian horses. However, some horses had a previous history of reproductive disorders, i.e., abortion and infertility. A total of 60 horses (39 mares and 21 stallions) were opportunistically recruited from 17 equine farms in central-northern Sardinia. Vaginal and uterine swabs from mares and urethral swabs and seminal fluid from stallions were sampled for the presence of chlamydial DNA. Samples from environments where the horses lived were also tested for the detection of Chlamydia spp. Eight vaginal swabs (8/39; 20%), two uterine swabs (2/27; 7%), two seminal fluid samples (2/20; 10%), and one urethral swab (1/21; 4.7%) were found to be positive for Chlamydia spp. by PCR analysis. In addition, results from environmental samples showed the presence of Chlamydia spp. in three environmental swabs (3/8; 37.5%) and five water samples (5/16; 31.2%). Sequencing results revealed that strains here identified were 99-100% similar to members belonging to the Chlamydiaceae family, including C. abortus, C. psittaci, and uncultured Chlamydia genotypes. ompA species-specific PCR performed on samples was found to be positive after 16S rRNA amplification gave positive results for C. psittaci. These results reveal the first presence of C. psittaci in the genital tract of horses and in the environment in Sardinia and indicate that this pathogen could be the prevailing cause of infertility and abortion in the tested equines. However, these findings need further proof and highlight the importance of adopting a 'One Health' approach to control the presence of this zoonotic bacteria in domestic animals in order to understand its impact on people exposed to the infection risk.
RESUMEN
Chlamydia psittaci is an intracellular bacterium belonging to the Chlamydiaceae family. It is the ethiologic agent of psittacosis, an occupational zoonotic disease that mainly concerns people who work in close contact with birds that represent the main infection route for human transmission. In Italy, information about this disease is lacking. This study is the first case of avian chlamydiosis reported from a pet shop in Sardinia, Italy. Chlamydia psittaci detected in psittacine birds by molecular analysis, direct immunofluorescence test together with anatomo-pathological observed lesions, highlighted the importance of focusing the attention over this underestimated zoonosis in a "One Health" prospective.
