Psittacosis

A friend of mine called me and asked about his sick bird. Since I never come across the bird diseases (particularly because we only learn domestic avians; not pet birds). I went through browsing the net about typical bird diseases; This is what I found out

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Etiology

The word psittacosis is derived from the Greek work Psittakos, which means parrot. It is a label for a disease in birds that has been recognized for the last century. Called psittacosis if it infects psittacines (parrots, parakeets, cockatoos, etc.), the same malady is termed ornithosis if it infects other types of birds. Other names include parrot fever and chlamydiosis.

The causative agent is Chlamydia psittaci. This "microvarmit" is like a bacteria (in that it responds to antibiotics) as well as like a virus (in that it will grow only on a tissue culture, not on bacterial media).

C. psittaci's ability to mystify us does not end with classification. It can cause disease in humans, other mammals and birds. It can kill a bird in 48 hours or it can survive in birds causing no outward sign of illness, for as long as 10 years. It can be explosively contagious or barely contagious. It can be destroyed by antibiotics easily or with incredible difficulty. It can be easy to diagnose or extremely frustrating. It can kill baby birds and cause no disease in their parents. It can live outside the body, as well as within. It can be easy to control or almost impossible. It causes massive flock outbreaks one year and none the next.

Transmission

Transmission of C. psittaci is also unsettling. The organism is shed in the nasal secretions and in the stool from infected birds, recovering birds and carriers. Once outside the body, the organism can live for a long period of time, drying to form dust and infecting the susceptible hosts as they breathe. Fecal and oral contamination are especially significant in crowded conditions, as well as in nest boxes.

As a general rule, inhaled Chlamydia will cause severe disease, while ingested Chlamydia will tend to develop into carriers.

Clinical signs

The clinical symptoms can be variable, depending on the species infected, the virulence of the agent, the route of exposure and concurrent stresses. The "typical psittacotic bird" is ruffled, depressed, has labored breathing, nasal and ocular discharge, and is neither eating nor vocalizing. The appearance of lime-green or yellow droppings, especially when the urine component is discolored.

One form of psittacosis seen infrequently manifests central nervous system signs. Tremors, shaking, head twisting and convulsions. This clinical peculiarity has been recognized in Amazons, African greys and cockatoos. Cockatiels can develop a psittacosis syndrome that causes paralysis of the limbs, and usually dark, tarry stools. Additionally, cockatiels and neophemas (turquoisines, scarlet-chested parakeets) with low-grade infections may seem to have an eye disease resembling a sty.

Fluffed feathers of Psittacosis bird

Infection in human

In humans the onset of psittacosis is abrupt with fever, chills, headache, muscle aches, general malaise and respiratory tract infections. Cough is often, but not always, a feature. The illness usually lasts for 7-10 days and is generally mild or moderate but may be severe or fatal in older, immunocompromised or untreated patients. The incubation period is 4-15 days.

Diagnosis

The identification of the organism is achieved by stains or a fluorescent antibody test.

Treatment

Most veterinarians use tetracycline and its derivatives, mainly Vibramycin, to treat sick patients as well as carriers. The antibiotic can be given by intravenous or intramuscular injections, orally or mixed in proper ratios with palatable food. Calcium must be withheld - it binds the tetracycline. Blood levels of tetracycline can be enhanced by citric acid in the birds' drinking water.

Patients in chlamydial crisis need intense, supportive care (heat, isolation, extremely clean conditions, absence from stress, etc.) as well as therapy for concurrent problems. Appropriate lactobacillus, as well as antifungal medications, are essential.

Control

Keeping susceptible birds away from the infecting agent. Since this little "microvarmit" can remain infective for many months in dried excrement, cleanliness and disinfection are essential. The Chlamydia species is inactivated by quaternary ammonium compounds. These disinfectants should be used to clean cages and wet-mopped on surrounding areas. Eliminating drafts and spraying the area with disinfectants will help keep infectious feathers and dust to a minimum. Birds that have had the disease or are under treatment are fully susceptible to reinfection since the disease does not convey immunity.

In wild birds, psittacosis is controlled naturally by the inability of sick birds to keep up with the flock. Additionally, infective droppings fall to the ground below the trees in which the birds perch. The clinical disease that we see in pets is promoted by confining, crowding, transporting, dietary changes, exposure to other infections and forced exposure to infective excrement.

Sources: Hotsport for birds understanding Psittacossis by Hannis L.Stoddard III & Burwood bird and animal hospital