Investigation of Lethal Concurrent Outbreak of Chlamydiosis and Pigeon Circovirus in a Zoo.

Wei-Tao Chen,Pao-Jung Wang,Chin-Ann Teng,Cheng-Hsin Shih,Chian-Ren Jeng,Yi-Fan Jiang,Hui-Wen Chang,Yen-Hsueh Lai,Chiu-Hung Cheng,Wei-Hsiang Huang,Yen-Chen Chang,Jun-Cheng Guo

doi:10.3390/ani11061654

Wei-Tao Chen, Pao-Jung Wang + Show 10 more

Open Access

https://doi.org/10.3390/ani11061654

Copy DOI

Abstract

Simple SummaryThe present study aimed to investigate a lethal outbreak of chlamydiosis and pigeon circovirus (PiCV) infection in a zoo. A retrospective follow-up indicates that the lethal outbreak might be an independent episode. The high prevalence of PiCV positivity in the aviaries suggests that PiCV infection might play a key role in augmenting the lethality of chlamydiosis in birds. Persistently monitoring both pathogens and identifying potential PiCV carriers or transmitters might also help prevent lethal disease outbreaks.During the spring, an outbreak of sudden death involving 58 birds occurred in a zoo. Histopathological examinations revealed variable numbers of intracytoplasmic basophilic microorganisms in the macrophages, hepatocytes, and renal epithelium of most birds, along with occasional botryoid intracytoplasmic inclusion bodies within histiocytes in the bursa of Fabricius. Based on the results of histopathological examinations, immunohistochemical staining, transmission electron microscopy, and polymerase chain reactions, genotype B Chlamydia psittaci infection concurrent with pigeon circovirus (PiCV) was diagnosed. A retrospective survey, including two years before the outbreak and the outbreak year, of C. psittaci and PiCV infections of dead birds in the aviaries, revealed that the outbreak was an independent episode. The findings of this study indicate that concurrent infection with C. psittaci and PiCV might lead to lethal outbreaks of chlamydiosis, particularly Streptopelia orientalis. In addition, persistently monitoring both pathogens and identifying potential PiCV carriers or transmitters might also help prevent lethal disease outbreaks.

Highlights

Chlamydia psittaci (C. psittaci) is a gram-negative obligate intracellular bacterium that can infect a wide range of hosts [1]
We report a lethal outbreak of C. psittaci in Columbiformes species in the aviaries, which were managed by the same group of keepers in a zoo
In the other 16 species across seven orders in the present study (Table 3), but no PiCVrelated histopathological lesions were observed in these species. These results suggest that Streptopelia orientalis might be more vulnerable to pigeon circovirus (PiCV) infection, which might lead to immunosuppression in this species and enhance the pathogenicity of other infections, such as lethal chlamydiosis

Summary

Introduction

Chlamydia psittaci (C. psittaci) is a gram-negative obligate intracellular bacterium that can infect a wide range of hosts [1]. More than 470 species from at least 30 orders are known to be susceptible to C. psittaci infection, among which psittacine birds, pigeons, and mynah birds are most commonly affected [2]. Infection of C. psittaci in birds, known as avian chlamydiosis or psittacosis, gives rise to a range of non-specific clinical manifestations with various degrees of severity, and in extreme cases, sudden death. Subclinical infections have been frequently reported in pigeons, older psittacine birds, and poultry [5]. C. psittaci can infect humans via inhalation of contaminants or contact with the eyes, resulting in asymptomatic signs, flu-like symptoms, or severe pneumonia. Individuals who are routinely in close contact with birds, such as birdkeepers, poultry workers, and veterinarians, are at a high risk of infection. Passing or transient contact with feral pigeons results in many (40%)

Methods

Results

Discussion

Conclusion