Psittacosis

Generality

Psittacosis, also called ornithosis or parrot disease, is an infection that humans usually contract from birds due to a bacterium called Chlamydia psittaci .

Figure: close contact with parrots and other infected birds favors the extraction of psittacosis. From the site: birdchannel.com

The birds capable of transmitting this infectious disease are: parrots, budgies, canaries, sparrows, pigeons etc.

To get sick, direct contact with urine, faeces, eggs or feathers of infected animals is required.

The less severe forms of psittacosis can be asymptomatic or characterized by flu-like symptoms; the most serious forms, on the other hand, can give rise to pneumonia.

For a correct diagnosis, a blood sample should be taken to measure antibody levels against the infecting bacterium. If the antibiotic therapy is adequate, healing takes place within 2-3 weeks.

What is psittacosis?

Psittacosis, also called ornithosis or parrot disease, is an infectious disease transmitted from birds to humans through the bacterium Chlamydia psittaci .

SOME INFORMATION ABOUT CHLAMYDIA PSITTACI

Chlamydia psittaci, or Chlamydophila psittaci, is a bacterium approximately 0.5 micrometres in size, belonging to the genus Chlamydophila, like the more famous Chlamydophila pneumoniae ( Chlamydia pneumoniae ).

Widespread especially among birds (in particular among parrots, canaries, budgies, pigeons, sparrows, ducks, hens and seagulls), this bacterium can be found very rarely even among cattle, pigs, sheep and horses.

As for birds, Chlamydia psittaci can reside in the gastrointestinal tract, in epithelial cells of most organs, in eggs, in excrements, in respiratory secretions and in plumage.

The bacterium can survive in the air for some time (even months), as it belongs to a very resistant species.

IS PSITTACOSIS A ZOONOSIS?

Psittacosis belongs to the class of zoonoses, or infectious diseases that are transmitted from animals to humans. Unless they adapt to the human species, zoonoses cause problems only to the individual who contracts them.

HISTORY AND EPIDEMIOLOGY

The first cases of psittacosis were recorded in Switzerland, in 1879: the 7 infected people fell ill with pneumonia after contact with birds typical of tropical areas.

The discovery of the infectious nature of psittacosis dates back to 1930, but the identification of the bacterium Chlamydia psittaci occurred only in 1960, after the advent of electron microscopy.

Today, the registered cases of psittacosis are few, mainly because the infection is often mistaken for a simple flu.

According to a US statistical research, from 2002 to 2009 the cases of ornithosis were just 66 (but probably the figure is underestimated).

Causes

Chlamydia psittaci can be transmitted from birds to humans through contact with urine, feces, respiratory secretions or the plumage of infected animals.

Very often, even the simple inhalation of air particles contaminated by the bacterium is sufficient.

Other less common transmission routes:

Contact mouth-beak of an infected bird
Infected bird pecking
Direct contact with body tissues belonging to an infected bird

HOW DO YOU NOTICE THAT A BIRD IS SICKED?

Birds infected with Chlamydia psittaci may look completely healthy ( latent infection ) or present the following pathological signs:

Extreme drowsiness
Chills
Body weight loss
Breathing difficulties
Diarrhea

In cases of latent infection, animals are nevertheless able to transmit the disease, especially when they are in a situation of stress (poor food, cages in which they live overcrowded, prolonged transport, forced coupling, etc.).

In cases where symptoms are evident, these can appear after a few days (3 in general) or after several weeks.

IS TRANSMISSION BETWEEN MAN AND MAN?

Human-to-human transmission is very rare and occurs only in cases of very serious infection.

RISK FACTORS

The people most at risk of psittacosis are those who spend a lot of time in close contact with birds, that is:

Bird lovers
Pigeon Breeders
Workers of poultry farms
Workers of companies that produce bird feeds
Employees of pet stores
Vets
Exotic bird breeders
Employees of diagnostic laboratories

Symptoms and Complications

Psittacosis has an extremely variable incubation time, which can range from 5 to 69 days.

The symptomatic picture depends on the severity of the infection: severe psittacosis can cause symptoms and signs similar to pneumonia ; mild or moderate psittacoses, on the other hand, can cause manifestations similar to those of a normal flu.

A general summary of all the possible effects of a Chlamydia psittaci infection is as follows:

Temperature
Chills
Cough
Breathing difficulties (in the most severe cases)
Sense of weakness and fatigue
Nose blood ( hemoptysis )
Muscle pain ( myalgia ) and joint ( arthralgia )
Chest pain
Loss of appetite
Nausea and vomit
Diarrhea
Headache
Excessive sweating
Intolerance to light
splenomegaly
Rosaceae also called "Horder spots"

In most cases, the typical incubation time is around 10.

WHY DO PSITTACOSIS CAUSE PULMONITE?

Psittacosis is primarily an infection of the respiratory tract and lungs. This explains why a serious Chlamydia psittaci infection can cause pneumonia, that is, a severe inflammation of the respiratory system.

PSYCHACOSIS ASINTOMATICA

Sometimes, psittacosis can also be asymptomatic or characterized by very mild symptoms. In these situations, the infection goes unnoticed, so it is not even diagnosed.

WHEN TO REFER TO THE DOCTOR?

Individuals most at risk of psittacosis (ie bird breeders, enthusiasts, etc.) should immediately contact their doctor, as a precaution, as soon as they experience flu-like disorders or suspicious respiratory tracts.

CAN PSITTACOSIS INTEREST MORE ORGANS? COMPLICATIONS

In addition to the lungs, psittacosis can involve other organs, such as the liver, heart, brain and / or cornea . The effects that may arise from these interests are: hepatitis (inflammation of the liver), endocarditis (inflammation of the endocardium, or the membrane that surrounds the internal cavities and valves of the heart), myocarditis (inflammation of the myocardium, ie the heart muscle ), encephalitis (inflammation of the brain) and keratoconjunctivitis (inflammation of the cornea and conjunctiva).

Diagnosis

To diagnose psittacosis, a blood sample of the suspect individual must be taken and its antibody content analyzed (ie the type of antibodies present). If there are antibodies against Chlamydia psittaci in the blood sample, it means that the patient under examination has psittacosis.

Although to a lesser extent than the antibody content, high levels of liver enzymes and low blood counts of white blood cells ( leukopenia ) and platelets ( thrombocytopenia ) may also be significant for diagnostic purposes.

Pathologies similar to psittacosis

Typhoid fever
Atypical pneumonia due to Mycoplasma pneumoniae
Legionella pneumonia
Q fever
Bird flu
Tularemia
Tuberculosis
Infective endocarditis

WHEN DOES THE DOCTOR NEED TO SUSPECT PSITTACOSI?

If the history shows that the patient with pneumonia-like symptoms spends a lot of time in close contact with the birds, the doctor is obliged to suspect psittacosis and to prescribe blood tests.

Treatment

Chlamydia psittaci infection is treated with antibiotics, in particular with tetracycline ( doxycycline and tetracycline hydrochloride ) and with chloramphenicol palmitate .

Generally, at the beginning of the therapeutic course it is better that the drug administration takes place intravenously.

The treatment should last about 2-3 weeks, even if the first improvements are already after just 48-72 hours. A premature suspension of treatment could slow healing and cause the same symptoms to reappear.

ARE THERE OTHER EFFECTIVE ANTIBIOTICS?

If tetracyclines and chloramphenicol are contraindicated (this is the case, for example, of young patients and pregnant women), it is possible to replace them with erythromycin .

MOST SERIOUS CASES

Patients with severe pneumonia symptoms should receive the classic treatments they need in such circumstances: then respiratory and cardiocirculatory support therapy, drainage of pleural effusions and painkillers.

Prevention

To prevent the spread of Chlamydia psittaci in a bird farm (but also in the domestic and recreational context), it is good to follow the following recommendations:

Administer safe food and at adequate doses.
Avoid overcrowding of the cages.
Provide the establishment where the animals are located with a suitable ventilation system. This serves to clean the air of any pathogenic microorganisms, including Chlamydia psittaci .
Avoid stacking the cages, so that faeces, feathers or food residues of a cage do not end up in the adjacent ones
Periodically clean the cages.

IN CASE OF SUSPECTED INFECTION

If it is suspected that some animal has been infected with Chlamydia psittaci, it is advisable to add a small dose of antibiotics to the administered food, and isolate the possible sick specimens.

Furthermore, it is recommended to disinfect all environments that come into contact with sick birds.

The disinfectants that can be used are: quaternary ammonium compounds, 70% ethanol, isopropyl alcohol, glutarladehyde and bleach.