- Advisory number:
- Date issued:
- 15 Dec 2020
- Issued by:
- Dr Annaliese van Diemen, Deputy Chief Health Officer (Communicable Disease)
- Issued to:
- Victorian consumers and health professionals
- There has been an increase in notified cases of psittacosis since 1 September 2020 within Victoria’s Alpine Local Government Area.
- Psittacosis is an uncommon type of lung infection (pneumonia) caused by the bacterium Chlamydia psittaci, and carried by wild birds in feathers, dander, secretions or droppings, which can be inhaled.
- Exposure is typically via contact with wild birds, recently purchased pet birds or pet birds kept outdoors.
- Symptoms including headache, fever, chills, muscle pains and a dry cough develop one to two weeks after exposure.
- These symptoms can be similar to those caused by COVID-19, so a COVID-19 test is recommended as well as a test for psittacosis.
- Psittacosis can be more serious in pregnant women, who should take particular care to avoid contact with birds.
- People who develop symptoms should seek medical attention. Antibiotics can be given to treat psittacosis.
- Person to person transmission of psittacosis is extremely rare.
- Psittacosis numbers can fluctuate seasonally, with environmental factors such as drought, floods and bushfires or anything affecting availability of food and causing stress in birds and their environment.
- Many of the recent cases from the Alpine region had indirect contact with wild birds via lawn mowing, gardening or other outdoor maintenance.
- To reduce the risk of exposure, avoid close contact with wild birds if possible, use a catcher and wear a dust mask when mowing lawns, and wash hands after tending pets or wild birds.
- Seek medical attention if pet or caged birds develop signs of a respiratory illness.
What is the issue?
The Department of Health and Human Services has been notified of 24 cases of psittacosis across Victoria since 1 September 2020. This is the highest number of notifications for this time period since 2012.
Ten of the recent psittacosis cases were residents of Alpine Local Government Area, which is an increase on the expected number of cases in this region.
Psittacosis is a relatively uncommon condition which is required to be notified by pathology services in Victoria.
Who is at risk?
At-risk groups include bird owners, pet shop employees, veterinarians, poultry-processing workers, zoo workers and taxidermists. The risk is greater for people who keep birds or maintain aviaries in which droppings and feathers can accumulate. Wild birds are a natural reservoir for the bacterium, and they excrete the bacteria when they are stressed, if something in their environment has changed. However, people can also contract Psittacosis from contact with wild birds.
Lawn mowing without a grass catcher and gardening have also been associated with disease transmission. Alpine areas of Victoria where wild birds are particularly abundant are also at increased risk.
Older adults and pregnant women may have a more severe illness. Immunocompromised people do not appear to be at increased risk of contracting the disease. Immunity following infection may be incomplete, and reinfection occurs occasionally.
Symptoms and transmission
Person-to-person transmission is extremely rare, with birds being the major reservoir of infection.
The clinical presentation can be variable, but the onset of psittacosis is usually sudden, with fever, prominent headache, photophobia, myalgia, and upper or lower respiratory tract symptoms. Dry cough is a common feature. The pulse may be slow relative to temperature; splenomegaly and rash may also occur. In association with pneumonia, these features are said to be suggestive of the diagnosis. Chest X-rays may show patchy or focal consolidation that can be more extensive than respiratory symptoms would suggest.
The illness usually lasts for 7–10 days and is mild or moderate in severity. It may be more severe in pregnant or older untreated patients. Asymptomatic infection or mild flu-like illness may also occur.
Complications include encephalitis, endocarditis, myocarditis and thrombophlebitis. Relapses may occur, especially when there has been inadequate treatment.
Symptoms of psittacosis can be similar to those caused by COVID-19, so a COVID-19 test is also recommended.
If there is clinical suspicion of Chlamydia psittaci infection, the following tests can help confirm the diagnosis:
- Polymerase chain reaction (PCR) performed on respiratory specimens is the preferred diagnostic method. Appropriate respiratory specimens include nasopharyngeal swabs, sputum specimens, and bronchoalveolar lavage specimens.
- If also collecting specimens for COVID19 PCR, please collect two swabs to enable testing in different laboratories.
- Serology may be useful for retrospective diagnosis. Paired acute and convalescent serologic samples taken 10-14 days apart are recommended. Antibiotic treatment may delay antibody response, so a third specimen collected after 8 weeks may be required.
Infection is generally acquired by inhaling dust from dried faeces or fresh or dried ocular and nasal secretions from infected birds, which may remain infectious for months. Direct contact with birds is not required for infection.
In response to the increased numbers, the following precautions are recommended:
- avoid breathing in dust from dried bird droppings, feathers or cage dust
- always wash hands thoroughly after tending to pet or wild birds
- avoid close contact with wild birds, for example, feeding or handling
- always use a catcher on lawn mowers and wear a dust mask or P2 respirator while mowing to avoid throwing up dust and dried bird droppings which can be inhaled
- seek medical attention if pet or caged birds develop signs of a respiratory illness.
Psittacosis is a ‘routine’ and must be notified by pathology services in writing within 5 days of diagnosis. Medical practitioners are not required to notify cases of psittacosis. This is a Victorian statutory requirement.
For more information please contact the Communicable Disease Prevention and Control section at the Department of Health and Human Services on 1300 651 160 (24 hours).
Reviewed 16 December 2020