Work

Inter-species transmission of Chlamydophila psittaci from broiler chickens to ducks, turkeys, pigeons, and quails: an experimental study

Year: 2026

Type: article

Abstract: Introduction Avian chlamydiosis (psittacosis), caused by Chlamydia psittaci , is a contagious bacterial disease of birds with significant economic and zoonotic importance. The infection spreads among avian species and to humans through contaminated secretions, feces, fomites, and close contact, posing challenges to poultry health and public health. Methods In the present study, at 1 day old, 90 birds (two chicken groups [one challenged positive control and the other kept unchallenged negative control], ducks, turkeys, pigeons, and quails) were divided into six equal groups (15 birds/group [species]). The birds were reared in a controlled environment on a deep-litter system, with conditions adjusted to their requirements. On the 7th day of age, the first broiler group (G1) was inoculated in both nostrils with 0.2 ml of C. psittaci at 10 6 inclusion-forming units (IFU) ml −1 . The other four groups of avian species, other than chickens, remained uninfected. When clinical signs appeared in broiler chicks, three infected chicks were transferred to each of the four experimental groups, while the second chicken remained in an unchallenged negative control group. Results Clinical signs appeared within 3–5 days post-contact. Turkeys showed the highest overall clinical susceptibility, where depression was observed in 14 of 15 birds (93.3%) and respiratory signs in 13 of 15 birds (86.7%), compared with 6 of 15 birds (40%) in chickens. Ducks, pigeons, and quails showed the lowest susceptibility, with only 5 of 15 birds (33.3%) affected. Postmortem (PM) lesions followed a similar pattern, with turkeys showing the most severe pathological changes. Histopathological examination confirmed inflammatory and degenerative alterations in several organs, particularly in turkeys and ducks. Molecular detection using quantitative real-time polymerase chain reaction (qRT-PCR) confirmed bacterial shedding. Discussion The current findings indicate that turkeys were the most susceptible species to C. psittaci infection, while chickens showed moderate susceptibility, with responses relatively comparable to ducks, pigeons, and quail, which showed the lowest percentage. Notably, turkeys were the first species to develop clinical signs and exhibited the most severe pathological lesions among the avian species examined. Therefore, it is advisable to enhance biosecurity protocols on mixed-species poultry farms, prioritize surveillance of turkeys given their heightened vulnerability, implement regular molecular monitoring to detect infections early, and segregate avian species during outbreaks to mitigate transmission.

Source: Frontiers in Veterinary Science

DOI: 10.3389/fvets.2026.1870801