Avian Bornavirus and Proventricular Dilatation Disease in Conures: Neurologic Signs Owners Should Know

Avian bornavirus is a virus that can infect parrots and other birds. In some conures, it is associated with proventricular dilatation disease (PDD), a disorder that inflames nerves in the digestive tract and sometimes the brain, spinal cord, heart, or other tissues. Merck notes that the disease is neurotropic, meaning it targets nervous tissue, which helps explain why some birds show stomach problems while others show tremors, weakness, or trouble balancing.

In the digestive tract, damaged nerves can slow normal movement of food. That may lead to a stretched proventriculus, weight loss despite a good appetite, regurgitation, and undigested food in the droppings. In the nervous system, affected conures may develop ataxia, tremors, seizures, weakness, or vision changes. Some birds have both digestive and neurologic signs at the same time, while others show one pattern first.

PDD is considered a serious condition. Clinical signs may come on gradually or appear more suddenly, and once a bird is clearly sick, long-term outlook is guarded. Still, the course can vary. Some conures decline quickly, while others may have periods of stability with supportive care directed by your vet.

Current veterinary sources link PDD in parrots to avian bornavirus, especially parrot bornavirus genotypes within psittaciform bornavirus 1 and 2. Merck reports that conures are among the species commonly affected. The virus is shed in feces and urine, so exposure may happen through contact with infected birds, contaminated surfaces, food dishes, or shared airspace and husbandry items.

Not every bird that tests positive for bornavirus develops obvious disease. That is one reason this condition can be confusing for pet parents. Some birds may carry or shed the virus without clear signs, while others go on to develop inflammation of the nerves that control digestion or movement. Stress, immune response, and individual susceptibility may all influence whether a bird becomes clinically ill, but the exact reasons one bird gets sick and another does not are not fully understood.

This is not caused by a diet mistake alone, and it is not something a pet parent can confirm at home. Because other illnesses can also cause weight loss, regurgitation, or neurologic changes, your vet will need to rule out look-alike problems such as heavy metal toxicity, bacterial or fungal disease, parasites, and other gastrointestinal disorders.

Diagnosis usually starts with a careful avian exam, body weight and body condition check, and a detailed history about appetite, droppings, regurgitation, and behavior changes. Your vet may recommend bloodwork and fecal testing to look for dehydration, infection, inflammation, or other diseases that can mimic PDD.

Imaging is often an important next step. VCA notes that radiographs can show an enlarged proventriculus, and contrast studies such as barium may help assess how food moves through the digestive tract. These tests do not prove bornavirus by themselves, but they can support the diagnosis and help your vet judge severity.

Bornavirus PCR testing on samples such as cloacal swabs, choanal swabs, or blood may be recommended. A positive result can support exposure or infection, but it does not always mean the bird has active clinical PDD. A negative result also does not fully rule it out, because shedding may be intermittent. In birds that die, necropsy with tissue evaluation by an avian pathologist remains the most definitive way to confirm PDD.

Prevention centers on biosecurity and early detection, because there is no simple home screening method and no guaranteed way to eliminate risk. New birds should be quarantined in a separate airspace when possible, with separate bowls, cleaning tools, and hand hygiene before and after handling. Merck and PetMD both emphasize that infected birds can spread virus through droppings and contaminated environments, so careful sanitation matters.

Routine wellness care with an avian veterinarian is also important. Regular weight checks can catch subtle decline before a conure looks obviously ill. If you keep multiple birds, talk with your vet about whether screening or repeat testing makes sense for your flock, especially before introducing a new bird or if one bird develops suspicious signs.

Good husbandry supports overall health even though it cannot fully prevent bornavirus exposure. Feed a balanced diet, reduce chronic stress, avoid overcrowding, and clean cages and food areas consistently. If one bird is suspected to have PDD, isolate that bird and ask your vet for a practical plan for testing, cleaning, and monitoring the rest of the household flock.