Psittacosis—also known as parrot fever, and ornithosis—is a
zoonotic
A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. ...
infectious disease
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...
in humans caused by a
bacterium
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
called ''
Chlamydia psittaci
''Chlamydia psittaci'' is a lethal intracellular parasite, intracellular bacterial species that may cause Endemism, endemic Bird, avian chlamydiosis, epizootic outbreaks in mammals, and respiratory psittacosis in humans. Potential hosts include ...
'' and contracted from infected
parrot
Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...
s, such as
macaw
Macaws are a group of New World parrots that are long-tailed and often colorful. They are popular in aviculture or as companion parrots, although there are conservation concerns about several species in the wild.
Biology
Of the many differe ...
s,
cockatiel
The cockatiel (; ''Nymphicus hollandicus''), also known as weiro (also spelt weero), or quarrion, is a medium-sized parrot that is a member of its own branch of the cockatoo family endemic to Australia. They are prized as household pets and com ...
s, and
budgerigar
The budgerigar ( ; ''Melopsittacus undulatus''), also known as the common parakeet or shell parakeet, is a small, long-tailed, seed-eating parrot usually nicknamed the budgie ( ), or in American English, the parakeet. Budgies are the only spe ...
s, and from
pigeon
Columbidae () is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with short necks and short slender bills that in some species feature fleshy ceres. They primarily ...
s,
sparrows,
duck
Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form t ...
s,
hen
Hen commonly refers to a female animal: a female chicken, other gallinaceous bird, any type of bird in general, or a lobster. It is also a slang term for a woman.
Hen or Hens may also refer to:
Places Norway
*Hen, Buskerud, a village in Ringer ...
s,
gull
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
s and many other species of birds. The incidence of infection in canaries and finches is believed to be lower than in
psittacine
Psittacinae is a subfamily of Afrotropical or Old World parrots, native to sub-Saharan Africa, which include twelve species and two extant genera. Among the species is the iconic grey parrot.
The ''Poicephalus'' are usually green birds wit ...
birds.
In certain contexts, the word is used when the disease is carried by any species of birds belonging to the family
Psittacidae
The family Psittacidae or holotropical parrots is one of three families of true parrots. It comprises the roughly 10 species of subfamily Psittacinae (the Old World or Afrotropical parrots) and 157 of subfamily Arinae (the New World or Neotropic ...
, whereas ornithosis is used when other birds carry the disease.
In humans
Signs and symptoms
In humans, after an incubation period of 5–19 days, the symptoms of the disease range from inapparent illness to systemic illness with severe
pneumonia
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity ...
. It presents chiefly as an atypical pneumonia. In the first week of psittacosis, the symptoms mimic
typhoid fever
Typhoid fever, also known as typhoid, is a disease caused by '' Salmonella'' serotype Typhi bacteria. Symptoms vary from mild to severe, and usually begin six to 30 days after exposure. Often there is a gradual onset of a high fever over several ...
, prostrating high
fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
s,
joint pains,
diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
,
conjunctivitis
Conjunctivitis, also known as pink eye, is inflammation of the conjunctiva, outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may ...
,
nose bleeds
A nosebleed, also known as epistaxis, is bleeding from the human nose, nose. Blood can flow down into the stomach, and cause nausea and vomiting. In more severe cases, blood may come out of both nostrils. Rarely, bleeding may be so significant t ...
, and
low level of white blood cells. Rose spots called Horder's spots can appear.
Spleen enlargement is common towards the end of the first week. It may become a serious lung infection. Diagnosis can be suspected in case of respiratory infection associated with splenomegaly and/or epistaxis.
Headache
Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
Headaches can occur as a result ...
can be so severe that it suggests
meningitis
Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...
and some
nuchal rigidity
Neck stiffness, stiff neck and nuchal rigidity are terms often used interchangeably to describe the medical condition when one experiences discomfort or pain when trying to turn, move, or flex the neck. Possible causes include muscle strain or sp ...
is not unusual. Towards the end of the first week, stupor or even
coma
A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...
can result in severe cases.
The second week is more akin to acute bacteremic
pneumococcal
''Streptococcus pneumoniae'', or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic (under aerobic conditions) or beta-hemolytic (under anaerobic conditions), aerotolerant anaerobic member of the genus Streptococcus. They are ...
pneumonia with continuous high fevers, headaches, cough, and
dyspnea
Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathing, breathe well enough. The American Thoracic Society defines it as "a subjective experience of brea ...
.
X-rays
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 Picometre, picometers to 10 Nanometre, nanometers, corresponding to frequency, ...
show patchy infiltrates or a diffuse whiteout of lung fields.
Complications in the form of
endocarditis
Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the ...
,
liver inflammation,
inflammation of the heart's muscle,
joint inflammation,
keratoconjunctivitis
Keratoconjunctivitis is inflammation ("-itis") of the cornea and conjunctiva.
When only the cornea is inflamed, it is called ''keratitis''; when only the conjunctiva is inflamed, it is called ''conjunctivitis''.
Causes
There are several potentia ...
(occasionally
extranodal marginal zone lymphoma of the lacrimal gland/orbit), and neurologic complications (
brain inflammation
Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations ...
) may occasionally occur. Severe pneumonia requiring intensive-care support may also occur. Fatal cases have been reported (less than 1% of cases).
Transmission route
The Chlamydia psittaci bacterium that causes psittacosis can be transmitted by mouth-to-beak contact, or through the airborne inhalation of feather dust, dried faeces, or the respiratory secretions of infected birds.
Person-to-person transmission is possible, but rare.
Diagnosis
Blood analysis usually shows a normal white cell count, but marked
leukocytosis
Leukocytosis is a condition in which the white cell (leukocyte count) is above the normal range in the blood. It is frequently a sign of an inflammatory response, most commonly the result of infection, but may also occur following certain parasi ...
is occasionally apparent.
Liver
The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...
enzymes are abnormal in half of the patients, with mild elevation of
aspartate transaminase
Aspartate transaminase (AST) or aspartate aminotransferase, also known as AspAT/ASAT/AAT or (serum) glutamic oxaloacetic transaminase (GOT, SGOT), is a pyridoxal phosphate (PLP)-dependent transaminase enzyme () that was first described by Arthur ...
. The erythrocyte sedimentation rate and C-reactive protein can be markedly elevated. Differential diagnosis must be made with typhus, typhoid, and atypical pneumonia by ''
Mycoplasma
''Mycoplasma'' is a genus of bacteria that, like the other members of the class ''Mollicutes'', lack a cell wall around their cell membranes. Peptidoglycan (murein) is absent. This characteristic makes them naturally resistant to antibiotics ...
,
Legionella
''Legionella'' is a genus of pathogenic gram-negative bacteria that includes the species '' L. pneumophila'', causing legionellosis (all illnesses caused by ''Legionella'') including a pneumonia-type illness called Legionnaires' disease and a mi ...
'', or
Q fever
Q fever or query fever is a disease caused by infection with ''Coxiella burnetii'', a bacterium that affects humans and other animals. This organism is uncommon, but may be found in cattle, sheep, goats, and other domestic mammals, including ...
. Exposure history is paramount to diagnosis.
Diagnosis involves
microbiological culture
A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diagn ...
s from respiratory secretions of patients or
serologically with a fourfold or greater increase in
antibody
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
titers against ''C. psittaci'' in blood samples combined with the probable course of the disease. Typical inclusions called "Leventhal-Cole-Lillie bodies"
can be seen within macrophages in BAL (bronchoalveolar lavage) fluid. Culture of ''C. psittaci'' is hazardous and should only be carried out in biosafety laboratories.
Treatment
The infection is treated with
antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...
s;
tetracycline
Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including Acne vulgaris, acne, cholera, brucellosis, plague (disease), plague, malaria, and sy ...
s and
chloramphenicol
Chloramphenicol is an antibiotic useful for the treatment of a number of bacterial infections. This includes use as an eye ointment to treat conjunctivitis. By mouth or by injection into a vein, it is used to treat meningitis, plague, cholera, a ...
are the choice for treating patients.
Most people respond to oral therapy
doxycycline
Doxycycline is a broad-spectrum tetracycline class antibiotic used in the treatment of infections caused by bacteria and certain parasites. It is used to treat bacterial pneumonia, acne, chlamydia infections, Lyme disease, cholera, typhus, an ...
,
tetracycline
Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including Acne vulgaris, acne, cholera, brucellosis, plague (disease), plague, malaria, and sy ...
hydrochloride, or chloramphenicol palmitate. For initial treatment of severely ill patients, doxycycline hyclate may be administered
intravenous
Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...
ly. Remission of symptoms is usually evident within 48–72 hours. However, relapse can occur, and treatment must continue for at least 10–14 days after fever subsides.
Epidemiology
Psittacosis was first reported in Europe in 1879.
In 1929, a highly publicized
outbreak of psittacosis hit the United States. Although not the first report of psittacosis in the United States, it was the largest up to that time. It led to greater controls on the import of pet parrots.
The aftermath of the outbreak and how it was handled led to the establishment of the
National Institutes of Health
The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...
.
From 2002 through 2009, 66 human cases of psittacosis were reported to the Centers for Disease Control and Prevention, and most resulted from exposure to infected pet birds, usually cockatiels,
parakeets
A parakeet is any one of many small to medium-sized species of parrot, in multiple genera, that generally has long tail feathers.
Etymology and naming
The name ''parakeet'' is derived from the French wor''perroquet'' which is reflected in ...
, and macaws. Many more cases may occur that are not correctly diagnosed or reported.
Bird owners, pet shop employees, zookeepers, and veterinarians are at risk of the infection. Some outbreaks of psittacosis in poultry-processing plants have been reported.
In birds
In birds, ''Chlamydia psittaci'' infection is referred to as avian chlamydiosis. Infected birds shed the bacteria through feces and nasal discharges, which can remain infectious for several months. Many strains remain quiescent in birds until activated under stress. Birds are excellent, highly mobile vectors for the distribution of chlamydial infection because they feed on, and have access to, the detritus of infected animals of all sorts.
Signs
''C. psittaci'' in birds is often systemic and infections can be inapparent, severe, acute, or chronic with intermittent shedding. Signs in birds include "inflamed eyes, difficulty in breathing, watery droppings, and green urates."
Diagnosis
Initial diagnosis may be by symptoms, but is usually confirmed by an
antigen
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. ...
and
antibody
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the ...
test. A
polymerase chain reaction
The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies (complete or partial) of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it (or a part of it) t ...
-based test is also available. Although any of these tests can confirm psittacosis, false negatives are possible, so a combination of clinical and laboratory tests is recommended before giving the bird a clean bill of health.
It may die within three weeks.
Epidemiology
Infection is usually by the droppings of another infected bird, though it can also be transmitted by feathers and eggs,
and is typically either inhaled or ingested.
''C. psittaci'' strains in birds infect mucosal epithelial cells and macrophages of the respiratory tract. Septicaemia eventually develops and the bacteria become localized in epithelial cells and macrophages of most organs, conjunctiva, and gastrointestinal tract. It can also be passed in the eggs. Stress commonly triggers onset of severe symptoms, resulting in rapid deterioration and death. ''C. psittaci'' strains are similar in virulence, grow readily in cell culture, have 16S-rRNA genes that differ by <0.8%, and belong to eight known
serovar
A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their surface antigens, allowing the epi ...
s. All should be considered to be readily transmissible to humans.
''C. psittaci'' serovar A is endemic among psittacine birds and has caused sporadic zoonotic disease in humans, other mammals, and tortoises. Serovar B is endemic among pigeons, has been isolated from turkeys, and has also been identified as the cause of abortion in a dairy herd. Serovars C and D are occupational hazards for slaughterhouse workers and for people in contact with birds. Serovar E isolates (known as Cal-10, MP, or MN) have been obtained from a variety of avian hosts worldwide, and although they were associated with the 1920s–1930s outbreak in humans, a specific reservoir for serovar E has not been identified. The M56 and WC serovars were isolated during outbreaks in mammals.
Treatment
Treatment is usually with antibiotics, such as doxycycline or tetracycline, and can be administered through drops in the water or injections.
Many strains of ''C. psittaci'' are susceptible to
bacteriophage
A bacteriophage (), also known informally as a ''phage'' (), is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν ('), meaning "to devour". Bacteri ...
s.
Use as a biological weapon
Psittacosis was one of more than a dozen agents that the United States researched as potential
biological weapon
A biological agent (also called bio-agent, biological threat agent, biological warfare agent, biological weapon, or bioweapon) is a bacterium, virus, protozoan, parasite, fungus, or toxin that can be used purposefully as a weapon in bioterroris ...
s before the nation suspended its
biological weapons program.
[Chemical and Biological Weapons: Possession and Programs Past and Present]
, ''James Martin Center for Nonproliferation Studies'', Middlebury College
Middlebury College is a private liberal arts college in Middlebury, Vermont. Founded in 1800 by Congregationalists, Middlebury was the first operating college or university in Vermont. The college currently enrolls 2,858 undergraduates from all ...
, April 9, 2002, accessed November 14, 2008.
Notable casualties
In 1930, during the
1929–1930 psittacosis pandemic, Lena Rose Pepperdine died of parrot fever.
She was the first wife of
George Pepperdine
George Pepperdine (; June 20, 1886 – July 31, 1962) was an American entrepreneur and Christian philanthropist who was the founder of Pepperdine University in California.
Biography Early life
George Pepperdine was born on June 20, 1886, on a far ...
, the founder of
Pepperdine University
Pepperdine University () is a private research university affiliated with the Churches of Christ with its main campus in Los Angeles County, California. Pepperdine's main campus consists of 830 acres (340 ha) overlooking the Pacific Ocean and t ...
.
References
* ''The initial content for this article was adapted from sources available at https://www.cdc.gov.''
External links
Psittacosis on Birds n WaysOrnithosis in Pigeons - Pigeonpedia
{{Authority control
Biological anti-agriculture weapons
Atypical pneumonias
Bacterial diseases
Biological weapons
Bird diseases
Poultry diseases
Respiratory diseases
Zoonotic bacterial diseases