Zoonotic transmission of Chlamydia psittaci in a chicken and turkey hatchery

Chlamydia psittaci is an obligately intracellular Gram-negative bacterium causing respiratory disease (chlamydiosis) or asymptomatic carriage in birds. C. psittaci is a zoonotic agent causing psittacosis or parrot fever in humans. Vertical and/or horizontal transmission via eggs might have serious repercussions on the C. psittaci infection status of poultry flocks and thus on zoonotic risk for all workers along the poultry supply chain. We therefore studied the presence of C. psittaci in a hatchery. In addition, we examined all (n = 4) employees of the hatchery to evaluate the zoonotic risk. We could not detect C. psittaci on either eggshells or eggshell membranes. However, C. psittaci isolates of different outer-membrane protein A (ompA) genotypes were cultured from the air of both turkey (genotypes A and C) and chicken (genotype D) hatching chambers. Zoonotic transmission occurred in all employees and a mixed infection with up to three different genotypes (A, D and C), also found in air samples, was discovered. Diagnostic monitoring and reporting of C. psittaci infections in poultry workers should be promoted. Additionally, an efficient veterinary vaccine and information campaigns on zoonotic risk and preventive measures against C. psittaci transmission would be beneficial to public health.