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    Compendium of Measures To Control Chlamydia psittaci Infection Among Humans (Psittacosis) and Pet Birds (Avian Chlamydiosis), 2000Psittacosis by Dr. Rob Marshall

    Psittacosis, also known as chlamydiosis or parrot fever, is a disease seen in birds, humans and other animals, and is caused by the bacteria Chlamydia psittaci.



    Symptoms depend upon the strain with which the bird in infected, the bird’s immune system status, species, age, and the presence of other concurrent infections. Mild outbreaks of psittacosis may go unnoticed because there will be very few symptoms. Alternatively there may be very mild respiratory symptoms and diarrhea (Avian Disease Manual, 1983)


    • Some bird species are more susceptible to this disease than others, including cockatiels, lovebirds and parakeets. Some become carriers and don’t show any symptoms of disease, but they can pass the bacteria on to other birds or their owners. Infected birds can remain asymptomatic until their immune system gets weakened for some reason, which usually happens when they experience stress.

      Typical Acute Symptoms may include any of the following (Gerlach, 1986b) :
      In acute cases, the affected bird becomes suddenly ill shortly after being infected.

      • Respiratory problems:
        • such as sinus infection, labored breathing, shortness of breath, noisy breathing or “runny nose”
      • General well-being:
        • eye discharge or swelling
        • lethargy, ruffled / fluffed-up feathers, loss of appetite, weightloss, weakness
      • Digestion:
        • dehydration, polyuria (excess urine); diarrhea or yellowish, grayish, or lime green urates

      Chronic Symptoms (Gerlach, 1986b)
      Chronic cases are more difficult to recognize. If untreated, it can lead to severe pneumonia and nonrespiratory health problems. Some infected birds remain assymptomatic.

      • Tremors and / or convulsive movements
      • Unusual head positions; Opisthotonos (neurologic disease in which the top of the head is bent over and approaches the back. Avian viruses, Function and Control, Branson W. Ritchie, DVM, PhD.)
      • Partial or complete paralysis of the legs


    Similar to influenza, with lethargy, fever, chest pains, dry cough, headaches and /or nauseay. Unlike flu, sore throats, runny nose, and large amounts of mucus may not be present.



    Chlamydophila psittaci is excreted in the feces and nasal discharges of infected birds. Infection usually occurs when a bird or a person inhales organisms that have been aerosolized from dried feces or respiratory tract secretions of infected birds. Other means of exposure include mouth-to-beak contact and handling infected birds’ plumage and tissues. Even brief exposures can lead to symptomatic infection. Some infected birds can appear healthy and shed the organism intermittently. Shedding can be activated by stress factors, including relocation, shipping, crowding, chilling, and breeding. At high risk are birds that are kept in overcrowded conditions, including pet stores, breeding facilities and multi-bird households – especially if new birds are added without following proper quarantine procedures.

    The organism is environmentally labile but can remain infectious for several months if protected by organic debris (eg, litter and feces).

    Macaws, cockatiels and amazons seem to be particularly susceptible. Young birds and birds that are stressed (by moving to a new home, ill, on a poor diet) also seem to be prime targets for infection.

    Chlamydia can also exist in a carrier state, in which the affected bird acts and looks normal, but can shed the bacteria and infect other birds in the household or aviary. This is particularly true with cockatiels, who have a notorious reputation as being carriers of psittacosis, many of which appear healthy or only mildly ill.

    Birds that survive Psittacosis may shed the organism intermittently in their feces for at least several months and possibly longer (Gerlach, 1986b). Clipsham (1988c) feels carriers may remain so for life, but may not always be a danger to other birds. Worrell (1986b) cites one case in which a bird with asymptomatic (latent) psittacosis developed overt psittacosis after a period of ten years, during which time exposure to other birds had not occurred. The discovery of nestlings of apparently healthy parents suddenly and inexplicably dead (either in the nest or at the bottom of the enclosure) could point to the presence of latent psittacosis in a breeding flock.




    Any bird suspected of having this disease should have a blood profile with a white blood cell count performed. A high white blood cell count and an elevation in liver enzymes indicating liver damage can signal infection with chlamydia. There are also several other blood tests available that test specifically for the presence of the chlamydia organism, or that detect the antibodies to the bacteria, indicating exposure. A positive test is usually definitive, and indicates current infection or recent exposure, however, a negative test does not always mean the bird is free of the disease, and other tests should be run in addition to assure the health of the bird.

    The physical condition of the bird should also play a role in the diagnosis of the disease.


    Diagnosis of psittacosis in humans can be made by isolation of C. psittaci or by serology. Serologic tests include complement fixation or immunofluorescent tests. However, individuals treated with antibiotics may not develop antibodies. A presumptive diagnosis is sometimes made, based on exposure to birds and clinical signs as described above under “Symptoms.”.


    Prognosis & Treatment:

    The outcome of treatment depends upon the individual bird’s species, age, immune status, length of illness before treatment was sought, the virulence of the strain with which it is infected, treatment protocol, and responsiveness to treatment. In general, the sooner the treatment commences, the better the prospects.

    Treatment is usually by the antibiotics Tetracyline or Doxycycline, however some newer drugs are also effective. Duration of treatment is for 45 days. All sources of calcium need to be removed for this period, as calcium affects the uptake of the antibiotic. Treatment of individual birds is done by twice daily dosing with liquid antibiotic, or by injections every ten days. In flocks where birds cannot be handled, or where there are too many birds to treat individually, medicated food or water can be given. Chlortetracyline (CTC) medicated food may be fed as the only source of food. Small birds, such as budgies, canaries and finches, may readily consume medicated seed and millet. Larger birds oftentimes do not accept this food readily. Sick birds may not eat and thus not receive any medication. If the pellets aren’t adequately consumed, insufficient antibiotic blood levels occur, resulting in treatment failure and continued shedding of chlamydia. In addition, because of the highly contagious nature of this bacteria, all birds in the household or aviary should be treated, not just the ill ones.



    High standard of flock husbandry important. Avoid producing dust, maintain good ventilation and screen flocks for the organism.

    • Quarantine:
      • All sick birds should be isolated
      • Contact with infected birds by humans should be kept to an absolute minimum.
      • Strict quarantine techniques should be applied.
    • Sanitation:
      • Thoroughly clean and disinfect cages, surroundings, and equipment used for a chlamydia patient. Quaternary ammonium disinfectants have proved very effective against this bacteria. (i.e. A-33, Barquat, Cetylcide, Floquat, Hitor, Merquat, Omega, Parvosol, Quintacide, Roccal, Zephiran. [Avian Viruses, Function and Control])
      • Keep circulation of feather dust to a minimum.
    • Testing:
      • Test birds with symptoms, such as diarrhea, weight loss or respiratory problems should be tested for this disease
    • Treatment:
      • Avian veterinarian may treat infected birds with Doxycycline for 45 days (or whatever he or she prescribes).
    • Human Infection:
      • Any flu-like symptoms in human caretakers requires immediate attention by a physician. The medical personnel needs to be alerted to the fact that psittacosis has been diagnoses, or is suspected. Psittacosis in humans is treatable, but without proper treatment can develop into a serious problem.



    by Dr. Rob Marshall


    After consulting with you, looking at your bird and from the tests I have taken, your bird has been diagnosed with Psittacosis. I have performed a Psittacosis test that has returned positive using a special ELISA test. When this test returns a weak positive result I like to confirm the accuracy. This is achieved by culture testing the throat and droppings. This culture test takes up to 24 hours to process. Please phone me for the results tomorrow evening. I will, however, begin a Psittacosis treatment immediately as a wise precaution.


    What is Psittacosis?
    Psittacosis is a serious infection of birds and humans which is caused by a virus-like bacteria called Chlamydia psittaci. Veterinarians call the disease Chlamydiosis and doctors call it Psittacosis. I will call it Psittacosis to avoid confusion. Most birds have been exposed to or may carry a disease but in this state it does not cause any problems and they are not contagious. However, Psittacosis may become highly contagious (it is spread by the air or by the droppings) from bird to bird and even from bird to human when stressful conditions arise. Stressful conditions for the bird may be anything which upsets the bird’s normal routine such as overcrowding, poor food quality, fungal and viral infections, a new home and so on.

    So why has your bird got this problem? Either it has been under stress or exposed to high levels of the Psittacosis germ. We must understand exactly how and why your bird has got this disease in order to prevent reinfection after the treatment programme has been completed. Unfortunately, birds do not develop immunity to this very serious illness.


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      How is Psittacosis treated?
      Psittacosis is a life threatening disease and the treatment programme includes an initial injection of Chlamydia treatment (doxycycline) which renders the bird non contagious within two days. Your ill bird must be hospitalised if it is not eating and crop fed until it is well enough to go home. Birds that are eating well are best treated as outpatients receiving a weekly injection or by medicating the drinking water or a soft food.

      The complete treatment takes six weeks. It is a very long course of treatment because the germ lives inside the cell for up to 45 days and the medicine must wait until the germ leaves the cell before it can be fully effective. Of course the treatment will not be effective if the bird does not drink enough of the medicine so you must check the water intake daily. Often the weekly injection course is the best avenue to follow. The germ in the cage or aviary must be killed at the same time as the germ in the bird to prevent reinfection. This is achieved by disinfecting with an appropriate cage cleaner today then once weekly for the six week Chlamydia treatment course.


      Are there any other special instructions?
      If the medication is given by treating the drinking water or soft food with Chlamydia treatment, Megamix must also be used. The addition of Megamix allows vitamin and mineral supplements to be given during the course of treatment. These supplements are important in accelerating the recovery process as Psittacosis is often related to vitamin, mineral and protein deficiencies.

      I recommend birds receive Turbobooster and F-Vite on a sterile seed, each day during treatment. Those receiving injections should also receive Dufoplus/Ioford in the drinking water daily for one week then twice weekly after this time. Following the Chlamydia treatment treatment your bird should revert to Dr. Marshall’s special health programme.

      I would advise your bird to return one week after the cessation of the Chlamydia treatment for a repeat ELISA test. This test ensures that your bird has fully recovered from the disease and is no longer contagious to you or other birds.


      Are there any long term problems?
      When detected early, the treatment for Psittacosis is remarkably successful as long as there are no underlying illnesses. This is why I recommend a culture test. Unfortunately when an underlying illness is left undetected, Psittacosis may become fatal irrespective of our every effort. In long standing but non fatal infections, Psittacosis can damage the immune system permanently making the bird susceptible to illness in the future. Psittacosis is commonly associated with infertility and the deaths of babies in breeding aviaries. In such aviaries we medicate before the breeding season to prevent problems. To protect your bird from stress related diseases like Psittacosis, follow one of Dr. Marshall’s health programmes.


      Is this disease contagious to humans and other birds?
      Psittacosis causes many different symptoms and is contagious to other birds and humans. All birds in contact with the ill bird must be treated for the full 45 day course. You must consult your doctor for a blood test to see if you have contracted the illness. The treatment in humans is a course of tablets if you have caught the illness and are not very sick with it. Humans can get kidney failure, severe liver disease and may even die if the disease is not identified and treated early enough. Signs of Psittacosis in humans include chronic fatigue, headaches, flu-like symptoms, nausea, chest pain, abdominal cramps and fever.

      The following recommendations may help keep your bird Psittacosis-free:

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        • Quarantine all new birds and Psittacosis test them before mixing with your flock.
        • Health check and Psittacosis test any new pet birds within 48 hours of purchase.
        • Clean and disinfect the cage or aviary once a week with an appropriate cage cleaner.
        • Use a weekly health programme.



        Psittacosis Treatment

        by Dr. Rob Marshall

        Chlamydia treatment Instructions for Pet Birds


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          Chlamydiosis (Psittacosis) is a serious and common disease frequently encountered in Budgerigars, canaries and parrots. The symptoms of Chlamydiosis are not always obvious. Eye infections, breathing difficulties, feather picking (itchiness) and lethargy are common signs in pet birds. The droppings are usually green in color and may be watery in nature.

          Psittacosis is diagnosed by a special cloacal sway test, together with a culture from the throat and of the dropping. Once diagnosed, treatment with Chlamydia treatment and Megamix is given for 45 days. This treatment in birds with Psittacosis will markedly improve the activity and happiness of your pet bird. Megamix is a citric acid solution and when mixed with the Chlamydia treatment antibiotic, it permits minerals and grits to be given during treatment. Dr. Marshall recommends that Turbobooster, F-vite and Energy supplement are mixed with sterile seed during the long antibiotic treatment. These additional supplements help recovery and limit the side effects often seen with prolonged antibiotic use. *See attached sheet.

          After treatment, reinfection with Psittacosis can occur immediately after this treatment for any of the following reasons:

          1. Re-infection from new untreated birds.
          2. Re-infection from other birds (especially wild or aviary parrots, pigeons, doves, finches or canaries).

          Dosage Instructions

          Type of Bird Dosage
          For Budgies, cockatiels, peach-faces and other parrots: Chlamydia treatment – ¼ teaspoon to 250 mls of water.Megamix – 1 ml (10 drops) to 250 mls of water.
          For doves, pigeons and poultry birds: Chlamydia treatment – ¼ teaspoon to 500 mls of water.Megamix – 2 mls to 500 mls of water.
          Lorikeets: Chlamydia treatment – ¼ teaspoon to 500 mls of water. Megamix – 2 mls to 500 mls of water.
          Canaries and finches: Chlamydia treatment – ¼ teaspoon to 500 mls of water. Megamix – 2 mls to 500 mls of water.

          Other Instructions

          1. Clean and disinfect cage one a week with an appropriate cage cleaner.
          2. At conclusion of treatment, return to our clinic for a repeat Psittacosis test.
          3. Introduce Ongoing Health Programme.

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          Information contained on this website is provided as general reference only. For application to specific circumstances, professional advice should be sought.