HEALTH RISKS TO HUMAN
- 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
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
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
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
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
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.
Avian Influenza
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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