Unprecedented outbreak: deadly avian disease sweeps through wild bird species in China

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) led not only to a pandemic of coronavirus disease 2019 (COVID-19) but heightened fears about emerging zoonotic diseases.

A new report from China published in the Animal Diseases Journal reveals the importance of Avibacterium paragallinarum as a potential avian pathogen, causing cold and even death among multiple avian species.

Study: Avibacterium paragallinarum: an emerging birds pathogen in Qinling wildlife conservation center, China. Image Credit: martin.dlugo/Shutterstock.comStudy: Avibacterium paragallinarum: an emerging birds pathogen in Qinling wildlife conservation center, China. Image Credit: martin.dlugo/Shutterstock.com


Infectious coryza (IC) is common among chickens and is caused by A. paragallinarum. It affects mainly the upper respiratory tract, leading to inflammation, swelling of the face, conjunctivitis, nasal discharge, diarrhea, and loss of appetite. Affected broiler and layer hens grow poorly and lay less, respectively.

Sometimes the infection becomes chronic, leading to prolonged respiratory tract disease, swollen head syndrome, inflammation of the air saccules, arthritis of the tarsal bones, and even septicemia. When complicated by other bacteria, it may cause increased mortality rates.

This makes it important to diagnose and treat the infection in a timely manner.

Some Avibacterium species are commensals, but others are pathogenic. A. paragallinarum is a gram-negative facultative anaerobe, which can colonize and adhere to the nasal mucosa early in infection. China practices vaccination to prevent this infection among poultry.

The commercial vaccine protects against Serovar A, B, and C. The bacterium is least resistant to cotrimoxazole. When treated with antibiotics, the birds stage a clinical recovery but remain lifelong carriers.

While IC has been reported in multiple countries, the present report focuses on an outbreak in Qinling, which marks the boundary between north and south China. The region is a biodiversity hotspot, containing several natural reserves.

Many endemic species under threat make their home here. Conservation programs operating here include captive breeding as well as wildlife surveillance.

The recent outbreak occurred among wild avian species in Qinling. The researchers analyzed the earliest isolated strain of A. paragallinarum from this area.

The outbreak

The first symptoms of infection were reported in a Golden pheasant in May 2022. It had facial edema, and the infraorbital sinuses presented a discharge. Similar signs were soon observed in a large number of wild birds at the Qinling wildlife shelter, all of which were from a natural reserve.

Despite quarantine and isolation measures, three more wild bird species developed signs of IC. Many of the affected birds had facial swelling. Several died, all of which showed swollen faces and growth failure.

In all, 18 Golden pheasants, two peafowls, and 57 Temminck tragopans were infected. Three of the Golden pheasants succumbed to it.

Postmortem examinations of Golden pheasants revealed that the infraorbital sinuses contained cheesy exudative material while slight bleeding into the trachea. The lungs were spared. The infected birds could not feed properly because of decreased vision.

Specific polymerase chain reaction (PCR) testing confirmed the presence of A. paragallinarum in symptomatic birds but not other species in the area. A common source of infection may have infected all the birds.

Phylogenetic analysis suggests that the strain responsible for the outbreak (LGT2022) has 96.5%-98.2% similarity to isolates from poultry.  

The infected birds were treated with sulfa drugs following sensitivity testing. Most recovered promptly, with full recovery within ten days of treatment. The last case was reported in February 2023.

What are the implications?

The study highlights the spreading of IC caused by A. paragallinarum among wild birds of the same and different species. This is the first such report, which is not common. Some affected species include the Golden pheasant, Temminck's tragopan, and Peafowls.

The resulting deficit in vision may cause affected birds to starve or fall prey to predators. The infection may present differently among different species of birds, and this gives a topic for further research.

The transmission of infectious protozoal disease in avian hosts may reduce the severity of A. paragallinarum infection in birds.

These findings are crucial for understanding the impact of A. paragallinarum infection on wild birds and developing effective prevention and control strategies to protect both commercial and wild birds."

While no novel cases have been observed, it is essential to continue collecting samples and testing for pathogens in this area to forestall further disease clusters.

Journal reference:
Dr. Liji Thomas

Written by

Dr. Liji Thomas

Dr. Liji Thomas is an OB-GYN, who graduated from the Government Medical College, University of Calicut, Kerala, in 2001. Liji practiced as a full-time consultant in obstetrics/gynecology in a private hospital for a few years following her graduation. She has counseled hundreds of patients facing issues from pregnancy-related problems and infertility, and has been in charge of over 2,000 deliveries, striving always to achieve a normal delivery rather than operative.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Thomas, Liji. (2023, June 27). Unprecedented outbreak: deadly avian disease sweeps through wild bird species in China. News-Medical. Retrieved on June 20, 2024 from https://www.news-medical.net/news/20230627/Unprecedented-outbreak-deadly-avian-disease-sweeps-through-wild-bird-species-in-China.aspx.

  • MLA

    Thomas, Liji. "Unprecedented outbreak: deadly avian disease sweeps through wild bird species in China". News-Medical. 20 June 2024. <https://www.news-medical.net/news/20230627/Unprecedented-outbreak-deadly-avian-disease-sweeps-through-wild-bird-species-in-China.aspx>.

  • Chicago

    Thomas, Liji. "Unprecedented outbreak: deadly avian disease sweeps through wild bird species in China". News-Medical. https://www.news-medical.net/news/20230627/Unprecedented-outbreak-deadly-avian-disease-sweeps-through-wild-bird-species-in-China.aspx. (accessed June 20, 2024).

  • Harvard

    Thomas, Liji. 2023. Unprecedented outbreak: deadly avian disease sweeps through wild bird species in China. News-Medical, viewed 20 June 2024, https://www.news-medical.net/news/20230627/Unprecedented-outbreak-deadly-avian-disease-sweeps-through-wild-bird-species-in-China.aspx.


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Study confirms no causal link between COVID-19 and ischemic priapism