Chlamydiosis, formerly called ornithosis, and most commonly known to human physicians as psittacosis, or archaic parrot fever, is caused by the organism Chlamydophila psittaci.
Bird owners should be fully informed of the implications and the potential for transmission to humans.
Transmission
Transmission of the disease is primarily through inhalation of contaminated dust from droppings or feathers.
Risk of infection is increased by close contact with infected birds that are shedding the organism.
For this reason, the disease is more common in stressed birds, such as birds experiencing shipping, overcrowding, or malnutrition, since birds tend to shed the organism when stressed.
Infected birds do not have to show specific signs of the illness in order to transmit the disease.
Clinical Signs
The visible signs of chlamydiosis are typically respiratory or gastrointestinal in nature.
Lime-green diarrhea is not an uncommon sign in many species.
Some birds may show general signs of illness, including:
- Lack of appetite
- Weight loss
- Depression
- Diarrhea
- Discharge from the eyes or nares
- Death
However, birds may exhibit few visible signs of illness, and these same signs can represent a number of other diseases.
Some birds that are actively infected with Chlamydophila psittaci may show no signs of illness.
An infected bird may carry the organism and not become identifiably ill until some stressful incident brings it out, if at all.
Breeding birds can pass the organism to their young.
Baby birds are more susceptible to severe infection than adult birds and may die in the nest or soon after weaning.
Diagnosis
A confirmed diagnosis of chlamydiosis in a live bird is sometimes difficult and depends on the species, length of time since exposure, and general condition of the bird.
The most commonly used diagnostic tests are:
- Polymerase chain reaction, DNA-PCR, assay
- Serology
- Culture of the organism
A positive test indicates the presence of disease but not necessarily an ill-appearing bird.
A negative test does not guarantee that a bird is not infected. Birds may shed the organism intermittently, so a negative test may need to be repeated.
Current recommendations are that a suspect bird be given more than one type of test and that these results be considered, along with the bird’s condition and history, to achieve a diagnosis.
Some veterinarians recommend treatment of all suspected cases with or without a positive test result.
The biggest problem with treatment is lack of compliance by the bird owner in completing the recommended course of medication.
Treatment
If chlamydiosis has been diagnosed, or if treatment has been recommended by your veterinarian, all exposed birds in the household should be treated at the same time to reduce the spread or recurrence of the disease.
It is imperative that infected birds be isolated during treatment and that certain sanitary measures be employed to prevent spread or reinfection of the disease.
The success of treatment depends on all of the medication being given in recommended dosage and time frame.
Antibiotic dosage and feeding should be directed by your veterinarian to ensure adequate levels are being consumed.
There are several ways to administer medication:
- By mouth
- By injection
- By mixture of antibiotic in soft foods or drinking water
- Through commercially available medicated pellets
Depending on the condition of the patient, other supportive treatment may be recommended as well.
Your veterinarian will discuss the most appropriate treatment for your bird.
Treatment must be continued for a minimum of 45 days to be effective.
During Treatment the Owner Must
Clean the premises with an appropriate disinfectant.
Use caution when handling droppings and cage debris, take care not to stir up dust while cleaning, and keep dust and feather circulation to a minimum.
Separate or isolate and seek medical care for other birds showing signs of disease.
Avoid contact with the birds by elderly, pregnant, sick or very young persons, immunosuppressed persons, or persons on anti-rejection drugs.
Remove all mineral supplements containing calcium, as calcium interferes with the medication.
Reduce stress in the bird’s environment as much as possible.
Follow all treatment instructions as prescribed by your veterinarian.
Transmission to Humans
Chlamydiosis is transmissible from birds to humans, although the incidence of transmission is rare considering the high incidence of infection in birds.
If anyone in the household with an infected bird develops persistent flu-like symptoms, respiratory distress, fever, chills, headache, weakness, or fatigue, that person should seek the advice of a physician as soon as possible.
Treatment is simple and most often successful in humans, but neglect of symptoms or delayed diagnosis may result in serious illness, especially in compromised persons.
Chlamydophila psittaci is not the same organism that causes genital Chlamydia infection in humans.
Preventative Measures
The following recommendations help reduce the increase of Chlamydia in flock companion birds.
Immediately after purchase, take all newly acquired birds to an avian veterinarian for chlamydiosis screening tests.
Buy birds from suppliers who routinely screen their birds for the presence of Chlamydophila psittaci or who are willing to stand behind the health of their birds in some manner, such as a health guarantee.
Isolate and quarantine all newly acquired birds for a minimum of six weeks.
Maintain appropriate preventative health management as recommended by your avian veterinarian.
For additional information on Chlamydia, spread of the disease and disinfection measures, please visit the following websites.
Center for Disease Control — Compendium of Measures To Control Chlamydia psittaci Infection Among Humans, Psittacosis, and Pet Birds, Avian Chlamydiosis
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr4908a1.htm
American Veterinary Medical Association — Psittacosis/avian chlamydiosis
http://avmajournals.avma.org/doi/pdf/10.2460/javma.2002.221.1710
