Equine chlamydiosis-An emerging infectious disease requiring a one health surveillance approach.

This study explores the infectious disease, Psittacosis, in horses and its potential risk to humans who come in contact with these animals. Despite intensive surveillance and testing, the researchers found no confirmed cases of acute Psittacosis among humans exposed to infected horses.

Background of the Study

• The research focuses on Psittacosis, a rare but severe infection typically related to bird contact.
• However, the pathogen responsible, Chlamydia psittaci, can also infect non-avian hosts including horses, sheep, cattle, and goats.
• The role of C. psittaci as an agent causing abortion in horses raised concerns about the risk it poses to humans who are often in contact with these animals, such as veterinary and breeding personnel.

Research Design

• The research team initiated a joint surveillance program focusing on both humans and animals in a central horse-breeding region in Australia.
• They cross-notified cases of equine Psittacosis to public health agencies and actively followed up with known human contacts. These contacts included stud workers, foaling staff, veterinarians, and laboratory staff – all individuals who have a high probability of coming into contact with the disease through their work.

Findings of the Study

• Despite rigorous surveillance and testing, the investigators found no confirmed instances of acute Psittacosis in people, even those with heavy exposure to infected horses.
• This initial finding indicates that the zoonotic risk (the chance of disease transmission from animals to humans) related to equine Psittacosis might be lower than initially thought.

Conclusions and Future Directions

• The researchers emphasize the need for additional work in the area to corroborate the preliminary findings and to further investigate the zoonotic potential of C. psittaci in horses.
• This study underlines the importance of a “One Health” approach, which considers the health of humans, animals, and the environment as interconnected. It also demonstrates the value of joint human-animal surveillance in controlling and preventing zoonotic diseases.