HEALTH RISKS TO HUMANS
- By DeAnn Waggoner, Executive Director of Wings of Love Bird Haven
Zoonotic diseases are diseases that are transmissable from animals to humans. Young children, elderly adults and individuals with poorly functioning immune systems are at the greatest risk of being infected by a zoonotic disease. While there are a number of diseases which can be transmitted by companion birds, many are more likely to be transmitted by poultry or wild birds. If your bird has been examined by an avian veterinarian and is considered healthy, the risks of infection are significantly reduced.
There are also some simple things you can do to mitigate any possible risk for you and your pet bird:
* Bathe your bird at least twice a week
* Do not keep birds in your bedroom
* Change cage papers/bedding daily if possible
* Air out your home in nice weather
* Switch to non-aerosol cleaning products and avoid using any chemicals. There are healthy plant-based products that you can buy to substitute. These are safer for both you and your pets.
* Buy and use a quality, HEPA air filter. In addition to doing an excellent job of capturing feather dust/down, these filters will reduce smog, household dust, mold, mildew, yeast and other allergens and toxins--all of which are unhealthy for you and your birds.
The following diseases in birds which are of reasonable significance include: Chlamydiosis (Psittacosis), Salmonellosis, Camphlobacteriosis, New Castles Disease, Allergic Alveolitus, Mycobacterosis (Avian Tuberculosis) Influenza, Giardia, and Cryptospondiosis. Chlamydiosis Chlamydiosis (also known as Psittacosis) is caused by a bacterial parasite. The disease in parrots and humans is called Psittacosis. It is called Ornithosis in bird species other than parrots. It is also called "parrot fever" in Psittacines. It can be transmitted to humans, birds, cows, goats, sheep and pigs. Most human cases are contracted from psittacines, pigeons and turkeys. It can also be transmitted from person to person.
The infected bird will shed the bacteria in their feces, urine, saliva ocular secretions, nasal exudates and feather dust. These infectious particles are inhaled or ingested by other birds and people. Egg transmission has also been documented. The incubation period in birds is several years. Symptoms in birds might include inflamed eyes, difficulty in breathing, watery droppings and green urates. Many birds are carriers and show no symptoms of the infection.
Humans are typically infected by the inhalation of the infected particles in the air. The incubation period is 5 to 14 days. Symptoms are generally flu-like fever, diarrhea, chills, congunctivitis and sore throat. There are several tests available to diagnosis the disease in a live bird. The newest is called PCR and is highly sensitive. Treatment for both humans and birds is doxycycline or tetracycline. People are treated for 3 weeks, while birds are treated for 45 days.
Salmonella is a gram negative aerobic bacteria that can infect birds, humans and other animals. It can persist in soil and water for long periods of time. A large number of serotypes exists. All types are capable of causing food poisoning. Birds can become infected with salmonella by oral ingestion of contaminated food, water and through the egg--either by ventical transmission or by penetration of the egg shell. Infected birds will appear lethargic, lose their appetite, have watery droppings and may develop arthritis. Parrots may also develop bloody diarrhea, profound depression, high white blood count and often die.
Most human cases of salmonella are acquired by eating contaminated food-- especially poultry rather than from pet birds. The incubation period is 6-72 hours in people. Vomiting, bloody diarrhea, fever and dehydration may occur. Recovery may occur in 2-4 days. Salmonella can be transmitted from person to person as well. Humans carrying salmonella can infect their pet birds too.
Diagnosis in the live bird can be difficult since bird may be intermittent shedders. Fecal or cloacal cultures are used for diagnosis. Birds are treated with aggressive antibiotics for 3-5 weeks based on culture and sensitivity. Birds may remain carriers of salmonella for life.
Antibiotics are not typically prescribed for people unless they have a prolonged fever and are septicmenic.
Allergic Alveolitis has a number of names among which include hypersensitivity pneumonitis, parakeet dander pneumoconiosis and pigeon lung disease. It occurs in people who are hypersensitive to feathers, feather dust, and fecal material--- especially from pigeons and parakeets. Signs can occur within two years but often takes as long as 10 to 20 years with continued exposure.
It may occur in an acute, sub-acute or chronic form. The acute form occurs within 4-8 hours of inhalation of a high level of feathers, dust and/or feces, difficulty breathing, chills and fever will occur. If exposure is stopped in time no treatment is necessary and signs will disappear. The sub-acute form results over long term exposure. A dry cough and progressive breathing difficulty occur. This form too may be reversed if exposure is halted. If continued exposure occurs, a chronic, nonreversible form occurs--leading to progressive difficulty breathing, a dry cough and weight loss.
Allergic alveolitis decreases lung capacity and causes impaired diffusion of air through the alveoli of the lungs.
Although this disease is thought to occur in genetically predisposed individuals, one can take certain steps to minimize dander in the environment. These steps include: cleaning cages daily, bathing birds frequently, avoid overcrowding, providing good ventilation and using a good air purification system.
Campylobacteriosis is caused by a gram negative. It can affect people and a variety of animals--especially parrots, finches and canaries. This bacterial organism lives in the small intestines and colon and may be isolated from clinically ill as well as healthy birds. Free-living wild birds maintain and spread the disease by the fecal-oral route. Clinically ill birds develop hepatitis, lethargy, loss of appetite, weight loss and yellow diarrhea. Mortality can be high.
People may become ill from eating contaminated poultry or poultry products. People develop cramps, fever, diarrhea and headaches within 2-5 days of exposure. Pregnant women, debilitated individuals, and the immuno-compromised are at the greatest risk. The risk is primarily from contaminated poultry rather than from pet birds. A blood test, culture and isolation of the organism from the feces may be used to diagnose the disease. Recovery occurs with appropriate antibiotics and support occurs within 7-10 days. Fecal cultures may be done to screen birds for camphylobacter.
Newcastle Disease is a paramyxo virus that can affect birds and people. It is more commonly seen in wild birds. The virus is shed through oral and respiratory secretions and through feces. It causes respiratory signs, diarrhea and neurologic signs--such as tremors, abnormal head position, circling and seizures in birds. Some birds may recover while others die.
The people who are at greatest risk are those who work in poultry processing plants or those who handle diseased wild birds. Incubation in people is only 1-2 days. Conjuntivitis, chills, fever and lethargy may develop. Recovery generally occurs within 3 weeks.
Diagnosis in birds and people is by virus isolation. There is no specific treatment other than support--fluids, rest and adequate nutrition.
Avian Tuberculosis (Mycobacterios)
Avian Tuberculosis occurs throughout the world and has been found in waterfowl, turkeys, psittacines, passerines, columbiformes and raptors. Tuberculosis is transmitted by ingestion and inhalation of aerosolized infectious organisms from feces. Incubation in birds is weeks to months. Any species can be infected, however this is most commonly found in Amazons and Green Cheek Conures. It is believed that immunocompetent humans are resistant to the strains of tuberculosis found in birds, but that immunocompromised people--such as those infected with HIV, those on chemotherapy, the elderly and children are at increased risk.
In adult humans, tuberculosis frequently affects the lungs, producing respiratory signs. In young children, the cervical lymph nodes are often involved, while immunocompromised people often have the disseminated form. Diagnosis of tuberculosis in the live bird can be very difficult due to intemittent fecal shedding and obscure signs. Physical finds, very elevated white blood cell and low red blood cell count and other diagnostic tests which include radiology (x-rays), endoscopy and identification of acid fast bacteria in feces or tissue can lead to a preliminary diagnosis. Definitive diagnosis is based on culturing the organism from the feces or from an organ.
If a positive bird is identified, it should be separated from the collection. Treatment of a positive bird is controversial because of the large number of organisms shed in the feces and because the organism is resistant to many of the drugs used to treat human T.B. The infected bird must be treated for a long period using combination drug treatment. All contact birds should be quarantined for 2 years and tested at 6- to 12-week intervals.
People who are infected with human tuberculosis should not own birds, since these people may serve as a source of infection for their pet birds.
Giardia is an intestinal protozoan that is found in the small intestine of infected birds, dogs, cats, humans and other mammals. The motile form, the trophozoite, attaches to the villi (fingerlike projections) of the small intestine by means of a sucking disk. The cyst form is passed in the feces (as well as the trophozoite) and is able to survivie in the environment.
People, birds and other animals become infected when they ingest contaminated food and water. Giardia cysts are not destroyed by standard chlorination. Boiling will destroy them, however.
The most frequently infected companion birds include budgies, cockatiels, lovebirds and grey cheeked parakeets. This may be the result of the way these birds are raised--in very densely populated environments. Other species may also be infected. Infected adult budgies and cockatiels (as well as other species) often appear clinically normal, but shed the infective cysts intermittently in their feces. Certain stresses, such as reproduction, molting or other diseases, may cause clinical signs such as the passing of voluminous, foul smelling, watery droppings, passing whole seeds in the droppings, ruffled feathers and death. The highest mortality is in nestlings and birds weakened by other illness. Some birds, especially budgies and cockatiels, are thought to become itchy as a result of a toxin secreted by the parasite. These birds tear out their feathers, frequently screaming as they do. People can develop severe cramping and diarrhea from Giardia.
Giardia appears to be limited in host range. The giardia infecting budgies is Giardia psittcai. It is unknown if these species can infect other types of birds. Giardia from mammals may infect humans, but the zoonotic potential for avian giardiasis is believed to be low, since it is not thought that avian giardia can infect mammals. Diagnosis of giardia in live birds can be difficult. Feces must be fresh--examined within ten minutes--in order to find the motile trophozite. If the feces cannot be examined immediately, it may be placed in polyvinyl alcohol and later trichrome stained for cysts. Multiple specimens may need to be examined because the parasite is shed intermittently.
Infected birds may be treated with metronidazole. Unfortunately, not all birds may be cleared and reinfection from the environment is common. Multiple courses of treatment are often necessary.
Quarantine, avoidance of overcrowding, and treatment of birds showing clinical signs will decrease the incidence of Giardia in a collection.
Influenza is caused by an enveloped RNA virus. It is an infectious disease of birds, swine, humans and other animals. Three types of Influenza viruses exist - types A, B, and C. Influenza A viruses infect birds and other animals, while B and C infect people.
Hundreds of subtypes of Influenza A viruses have been isolated from birds and other mammals. Influenza viruses are continuously undergoing change, resulting in new serotypes. Migratory birds, especially waterfowl are believed to be reservoirs for Influenza A virus. The infection often causes an inapparent intestinal disease in waterfowl. These infected waterfowl don't show signs of disease unless severely stressed by other diseases or transport. These unapparently infected birds shed the virus from their respiratory tract, conjunctiva (lining of the eyes) and in their feces - serving as a source of infection for other birds. Incubation may be as short as a few hours.
The signs of illness depend upon the species infected, the age, environmental factors, and virulence of the viral strain. Birds may die suddenly without showing signs of illness or develop depression, appetite loss, coughing, sneezing and decreased egg production.
Influenza A has been isolated from captive birds, including psittacines (parrots) and passerines (canaries, finches, sparrow, starlings, etc). Psittacines my demonstrate loss of balance, torticollis (twisted neck) and may die.
The virus may be isolated from swabs of the cloaca and upper respiratory tract in the live bird. It may be isolated from the lungs, liver, spleen and brain at postmortem. A companion bird could serve as a source of virus exposure for humans, but it is more likely that humans could serve as a source of virus exposure for susceptible companion birds. If a human has clinical signs of the "flu", he should avoid contact with his bird.
Wild migratory birds should not be allowed contact with companion birds, chickens and turkeys - as they may serve as a means of spreading Influenza.
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