Avian Chlamydiosis (Psittacosis) in Macaws

Avian chlamydiosis, also called psittacosis or parrot fever, is an infectious disease caused by the bacterium Chlamydia psittaci. Macaws are part of the psittacine family, so they are among the bird groups commonly affected. The organism can infect the respiratory tract, liver, spleen, eyes, and digestive tract, which is why the signs can look very different from one bird to another.

This disease matters for two reasons. First, it can make a macaw quite sick, especially if the bird is stressed or already dealing with another illness. Second, it is zoonotic, which means people can become infected from contaminated dust, droppings, or respiratory secretions. That does not mean every exposed person gets sick, but it does mean a coughing, lethargic, or diarrhea-prone macaw should be handled carefully until your vet says otherwise.

Some macaws show obvious illness, while others become carriers and shed the organism off and on. Because shedding can be intermittent, a bird may look better for a few days and still need testing and treatment planning. Early veterinary care helps protect both your bird and the people around them.

Avian chlamydiosis is caused by infection with Chlamydia psittaci. Macaws usually become infected by inhaling or ingesting contaminated material from droppings, feather dust, respiratory secretions, or dried debris in the environment. Close housing, poor ventilation, transport, rehoming, breeding stress, and mixing birds from different sources can all increase risk.

A challenging part of this disease is that infected birds do not always shed the organism continuously. A macaw may appear normal, then start shedding during times of stress or illness. That means a newly adopted bird, a bird from a store or breeder, or a bird exposed to other parrots can carry infection without dramatic signs at first.

Spread is more likely when cages are crowded, stacked so droppings fall between birds, or cleaned in ways that aerosolize dust. Dry sweeping and vacuuming around contaminated cages can push infectious particles into the air. Because people can also become infected, your vet may recommend temporary isolation of the sick macaw and extra hygiene steps for everyone in the home.

Diagnosis usually starts with a careful history and exam. Your vet will ask about recent bird purchases, boarding, travel, contact with other birds, appetite changes, droppings, breathing signs, and whether anyone in the household has become ill. Because psittacosis can mimic other bird diseases, testing is important rather than guessing from symptoms alone.

PCR testing is commonly used to look for C. psittaci DNA. Your vet may collect a combination of choanal, conjunctival, and cloacal swabs, and in some cases may also recommend fecal testing. A negative result does not always rule the disease out, because infected birds may shed intermittently. If suspicion stays high, repeat testing or additional sample types may be needed.

Bloodwork can help assess inflammation, dehydration, and liver involvement. Radiographs may be recommended if your vet is concerned about pneumonia, enlarged liver, or other internal changes. In a very sick macaw, diagnosis and treatment may overlap, with supportive care started right away while confirmatory results are pending.

Prevention starts with smart quarantine and low-stress husbandry. Any new bird should be kept separate from resident birds before introductions, and your vet may recommend testing during that period. Avoid housing birds so droppings, dust, or food debris can pass from one cage to another. Good ventilation, daily cleaning of bowls and cage surfaces, and avoiding overcrowding all help lower risk.

How you clean matters. Wet surfaces with water or an appropriate disinfectant before cleaning so dried droppings and feather dust do not become airborne. Avoid dry sweeping or vacuuming around contaminated material. Wash hands well after handling birds, cages, bowls, or droppings, and do not clean bird supplies in kitchen sinks or food-prep areas.

If a macaw is suspected or confirmed to have psittacosis, isolate that bird and follow your vet’s instructions closely. In multi-bird homes, your vet may recommend testing or monitoring exposed birds even if they seem healthy. There is no routine vaccine for pet macaws for this disease, so prevention depends on quarantine, sanitation, reduced stress, and early veterinary attention when signs appear.