What is Psittacosis Pneumonia?
Psittacosis is a systemic disease, which means it affects the body as a whole. It can cause an unusual form of pneumonia when it infects the lungs. It’s also known as avian chlamydiosis, ornithosis, and parrot fever. Psittacosis is caused by a type of bacterium, called Chlamydia psittaci, that humans can catch primarily from birds.
All birds can carry this disease, but pet birds and poultry birds such as chickens are most often the sources of transmission to humans. The bacterium can infect humans through direct contact with birds, bird nasal secretions, infectious bird feces, or even by inhaling dust from bird feathers. So far, there have been no confirmed cases of the disease being passed from person to person.
Chlamydia psittaci played an important role in the history of chlamydia research. It was used as a model organism in the 1960s and 1970s, which paved the way for modern research into this group of bacteria. There have been multiple severe outbreaks as early as 1879, including one in the United States that contributed to the establishment of the National Institute of Health in 1930. Today, psittacosis is recognized for its financial impact on the poultry industry due to the disease’s effect on birds.
What Causes Psittacosis Pneumonia?
Chlamydia psittaci is a type of bacteria that can only live inside the cells of a host. It’s commonly found in poultry, like turkeys and ducks, as well as pet birds, including parrots, cockatiels, macaws, and parakeets. It can also exist in other animals like cattle, sheep, pigs, horses, goats, cats, and even in wildlife. However, it’s important to note that it hasn’t been definitively proven that these non-bird animals can get sick from the bacteria or pass it onto humans.
Risk Factors and Frequency for Psittacosis Pneumonia
Chlamydia psittaci is a notable source of a type of lung infection called community-acquired pneumonia (or CAP). It makes up about 1% of all such pneumonia cases. Less than 50 cases of this disease, often called psittacosis, are recorded in the United States each year. People who likely have high exposure to this infection include those who own pet birds or who work at places like poultry-processing centers, pet stores, bird aviaries, or veterinary facilities.
Since regular tests for this are not conducted, it’s hard to know exactly how common it is. The bacteria are transmitted when people breathe in droplets that are present in bird feces, urine, respiratory secretions, and feather dust. Even when the bacteria are dry, they can still cause illness for several months. Psittacosis tends to occur more frequently in young to middle-aged males, which could be due to them having a higher chance of being exposed.
Signs and Symptoms of Psittacosis Pneumonia
Psittacosis is a disease usually caught from birds, often impacting young to middle-aged males. It can cause a range of symptoms, typically starting with fever, chills, headaches, muscle aches, and a dry cough. In more severe cases, it may affect the whole body and cause liver and spleen enlargement, heart inflammation, and digestive problems. In rare cases, people may even experience confusion or other mental changes. The disease takes about 5 to 19 days to show symptoms after exposure, but in some instances, this could be as long as 28 days. Before antibiotics were developed, this disease was often fatal. Nowadays, it’s quite rare because we have not only antibiotics but also bird quarantine rules and better hygiene standards.
- Most common symptom is fever
- Chills
- Headaches
- Muscle aches
- Dry cough
- Potential liver and spleen enlargement in severe cases
- Heart inflammation in severe cases
- Digestive issues
- Mental changes in rare instances
Pulmonary symptoms include a persistent dry cough. During a physical exam, a doctor might hear crackling or rattling sounds in the patient’s lungs. In rare instances, a rubbing sound may be detected in the relationship between the lung and chest wall. Fever accompanied by an abnormally slow heart rate is another symptom specific to psittacosis pneumonia. If the disease spreads throughout the body, other symptoms may include light sensitivity, nosebleeds, tinnitus, deafness, digestive issues, and joint aches.
Testing for Psittacosis Pneumonia
If you’re being tested for a C. psittacosis infection, your doctor will most likely use a blood test known as the micro-immunofluorescent antibody test (MIF). This test looks for specific antibodies that your body produces in response to chlamydia-specific surface antigens (proteins found on the surface of the bacteria). If your antibodies are above a certain level (1:16), it indicates you’ve been exposed to the bacteria. A fourfold increase, combined with your symptoms, would confirm the diagnosis. Previously, the main diagnostic test was Complement fixation (CF), but this can’t differentiate between different species of chlamydia and so it’s not used as much now.
They might also take a look at your white blood cell count. Even if it’s normal, they might observe a “left shift,” which essentially means that there are more immature white blood cells than usual. They might also run tests for Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), both of which can increase when there’s inflammation in your body. If the infection has spread throughout the body, the doctor might observe abnormal liver enzymes, low sodium levels (hyponatremia), and elevated BUN/creatinine levels, which are indicators of kidney function.
Doctors might also use imaging to get a better idea of what’s happening inside the body. Chest x-rays often show changes in the lower part of the lungs. Computed Tomography (CT) scans are more sensitive and may reveal small nodules (or knots) in the lungs, along with a hazy area known as “ground-glass” opacity.
Treatment Options for Psittacosis Pneumonia
The main form of treatment for a C. psittaci infection is a type of antibiotic called tetracyclines. Tetracycline and Doxycycline are among the forms of tetracyclines often used to treat this infection effectively. Minocycline, another tetracycline antibiotic, may also be used.
If tetracyclines are not suitable, other types of antibiotics, known as macrolides, are used as second-choice treatments. Azithromycin is usually preferred over another macrolide, erythromycin. For children who have a C. psittaci infection, macrolides are typically the preferred treatment option.
What else can Psittacosis Pneumonia be?
The first signs of C. psittaci, which is a bacteria causing infection often spread by birds, include fever, headache, and a dry cough. These symptoms can hint towards many potential illnesses. Therefore, doctors have a long list of conditions to rule out, such as:
- Atypical pneumonia caused by different bacteria like Chlamydia pneumoniae or fungi
- Other infections similar to pneumonia, like mycoplasma infections, Legionnaires’ disease, Q fever, and Tularemia
- Influenza
- Septicemia (blood infection)
- Endocarditis (infection of the heart lining)
- Other types of pneumonia, including those caused by bacteria or fungi
- Various other infections
During their examination, doctors will consider whether the patient has been exposed to birds or bird droppings. Such a scenario can often be found in places like under bridges and would point more toward C. psittaci infection.
What to expect with Psittacosis Pneumonia
The outlook for someone with C. psittacosis, a type of bacterial infection, largely hinges on their overall health, how severe their infection is, and whether they are diagnosed and treated early. Recovery can take 6 to 8 weeks, which might include some lasting changes seen in chest X-rays.
According to the CDC, the current mortality rate in the United States is less than 1% when the infection is diagnosed early and treated appropriately.
Possible Complications When Diagnosed with Psittacosis Pneumonia
Pneumonia is not the only problem that can occur if you’re infected with C. psittaci. This infestation can cause problems throughout your body. Specifically, it can cause endocarditis (an inflammation of the heart’s inner lining), hepatitis (liver inflammation), and encephalitis (brain inflammation).
- Endocarditis (an inflammation of the heart’s inner lining)
- Hepatitis (liver inflammation)
- Encephalitis (brain inflammation)
Preventing Psittacosis Pneumonia
Parrot fever, also known as Psittacosis pneumonia or ornithosis, is a type of infection that you can catch from birds. Common symptoms include sudden fever, headache, body aches, and a dry cough. Certain groups have a higher risk of getting this infection, including pet bird owners, pet shop employees, vets, and people who work at poultry processing plants.
In severe cases, the bacteria causing the infection (C. psittaci) can impact not only the lungs but also the kidneys, liver, and central nervous system which is your brain and spinal cord. This disease can be very serious, potentially even life-threatening, which is why it’s important to start antibiotics as soon as possible. You usually need to take these for 7 to 10 days.
The Centers for Disease Control and Prevention (CDC) advice is to only buy pet birds from reputable pet stores. They also recommend that if you own pet birds or poultry, you should use good hygiene practices when handling and cleaning birds and cages to help prevent infections.
