Find information on thousands of medical conditions and prescription drugs.

Q fever

Q fever is a zoonosis caused by the strictly intracellular, gram negative bacterium Coxiella burnetii which proceeds asymptomatic and self-limiting in 60% of the cases. The infectious organism is commonly found in cattle, sheep, goats and other domestic mammals. more...

 Home
Diseases
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
Q fever
R
S
T
U
V
W
X
Y
Z
Medicines

The infection results from inhalation of contaminated particles of the inhaled air. The incubation time is 9-40 days. It is considered possibly the most infectious disease in the world, as a human being can be infected by a single bacterium.

History

It was first described by Edward Holbroock Derrick in abattoir workers in Brisbane, Queensland, Australia as a disease of unknown origin and therefore “query fever”. In 1937 the bacterium was isolated by Frank MacFarlane Burnet and Freeman from one of Derrick’s patients for the first time and identified as Rickettsia-species. H.R. Cox and Davis isolated the pathogen from ticks in Montana, USA in 1938, described the transmission and it was officially named Coxiella burnetii the same year. Meanwhile Coxiella burnetii is no longer regarded as closely related to Rickettsiae.

Manifestations

The most common manifestation is flu-like symptoms with abrupt onset of fever, malaise, severe headache, myalgia (muscle pain), loss of appetite, dry cough, pleuritic pain, chills, confusion and gastro-intestinal symptoms such as nausea, vomiting and diarrhoea. The fever lasts approximately 7-14 days.

During the course, the disease can progress to an atypical pneumonia, which often results in a life threatening acute respiratory distress syndrome (ARDS), whereby such symptoms usually occur during the first 4-5 days of infection.

Less often the Q fever causes (granulomatous) hepatitis which becomes symptomatic with malaise, fever, liver enlargement (hepatomegaly), pain in the right upper quadrant of the abdomen and jaundice (icterus).

The chronic form of the Q fever is virtually identical with the inflammation of the inner lining of the heart (endocarditis), which can occur after months or decades following the infection. It is usually deadly if untreated. However, with appropriate treatment this lethality is around 10%.

Appearance and incidence

The pathogenic agent is to be found everywhere except Antarctica and New Zealand. In Europe it rather appears as hepatitis and rather as pneumonia in the United States. The bacterium is extremely sustainable and infectious: a single one is able to cause an infection. The common way of infection is inhalation of contaminated dust, contact with contaminated milk, meat, wool and particularly birthing products. Ticks can transfer the pathogenic agent to other animals. Transfer between humans seems extremely rare and has so far been described in very few cases.

Men are slightly more often affected than women, what most likely is attributed to exposition in typical professions such as livestock breeding, dairy and meat production. A vaccination exists and its use is recommended to exposed people in some countries.

Read more at Wikipedia.org
• [List your site here Free!]

Q fever
From Gale Encyclopedia of Medicine, 4/6/01 by Rosalyn S. Carson-DeWitt

Definition

Q fever is an illness caused by a type of bacteria, Coxiella burnetii, resulting in a fever and rash.

Description

C. burnetii lives in many different kinds of animals, including cattle, sheep, goats, tick, cats, rabbits, birds, and dogs. In sheep and cattle, for example, the bacteria tends to accumulate in large numbers in the female's uterus (the organ where lambs and calves develop) and udder. Other animals have similar patterns of bacterial accumulation within the females. As a result, C. burnetii can cause infection through contaminated milk, or when humans come into contact with the fluids or tissues produced when a cow or sheep gives birth. Also, the bacteria can survive in dry dust for months; therefore, if the female's fluids contaminate the ground, humans may become infected when they come in contact with the contaminated dust.

Persons most at risk for Q fever include anybody who works with cattle or sheep, or products produced from them. These include farm workers, slaughterhouse workers, workers in meat-packing plants, veterinarians, and wool workers.

Q fever has been found all over the world, except in some areas of Scandinavia, Antarctica, and New Zealand.

Causes & symptoms

C. burnetii causes infection when a human breathes in tiny droplets, or drinks milk, containing the bacteria. After 3-30 days, symptoms of the illness appear.

The usual symptoms of Q fever include fever, chills, heavy sweating, headache, nausea and vomiting, diarrhea, fatigue, and cough. Also, a number of other problems may present themselves, including inflammation of the liver (hepatitis); inflammation of the sac containing the heart (pericarditis); inflammation of the heart muscle itself (myocarditis); inflammation of the coverings of the brain and spinal cord, or of the brain itself (meningoencephalitis); and pneumonia.

Chronic Q fever occurs most frequently in patients with other medical problems, including diseased heart valves, weakened immune systems, or kidney disease. Such patients usually have about a year's worth of vague symptoms, including a low fever, enlargement of the spleen and/or liver, and fatigue. Testing almost always reveals that these patients have inflammation of the lining of the heart (endocarditis).

Diagnosis

Q fever is diagnosed by demonstrating that the patient's immune system is making increasing numbers of antibodies (special immune cells) against markers (antigens) that are found on C. burnetii.

Treatment

Doxycycline and quinolone antibiotics are effective for treatment of Q fever. Treatment usually lasts for two weeks. Rifampin and doxycycline together are given for chronic Q fever. Chronic Q fever requires treatment for at least three years.

Prognosis

Death is rare from Q fever. Most people recover completely, although some patients with endocarditis will require surgery to replace their damaged heart valves.

Prevention

Q fever can be prevented by the appropriate handling of potentially infective substances. For example, milk should always be pasteurized, and people who work with animals giving birth should carefully dispose of the tissues and fluids associated with birth. Industries which process animal materials (meat, wool) should take care to prevent the contamination of dust within the plant.

Vaccines are available for workers at risk for Q fever.

Key Terms

Antibodies
Specialized cells of the immune system that can recognize organisms that invade the body (such as bacteria, viruses, and fungi). The antibodies are then able to set off a complex chain of events designed to kill these foreign invaders.
Antigens
Markers on the outside of bacteria or viruses which can be recognized by antibodies.
Immune system
The system of specialized organs, lymph nodes, and blood cells throughout the body which work together to prevent foreign invaders (bacteria, viruses, fungi, etc.) from taking hold and growing.
Inflammation
The body's response to tissue damage. Includes increased heat, swelling, redness, and pain in the affected part.

Further Reading

For Your Information

    Books

  • Corey, Lawrence. "Rickettsia and Coxiella." In Sherris Medical Microbiology: An Introduction to Infectious Diseases, edited by Kenneth J. Ryan. Norwalk, CT: Appleton and Lange, 1994.
  • Walker, David, et al. "Rickettsial Diseases." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.

    Periodicals

  • "Q Fever Outbreak: Germany, 1996." Morbidity and Mortality Weekly Report 46, no. 2 (January 17, 1997): 29+.
  • Valero, Frank. "Pericardial Effusion as the Initial Feature of Q Fever." American Heart Journal 130, no. 6 (December 1995): 1308+.

    Organizations

  • Centers for Disease Control and Prevention. 1600 Clifton Road NE, Altanta, GA 30333. (404) 332-4559. http://www.cdc.gov.

Gale Encyclopedia of Medicine. Gale Research, 1999.

Return to Q fever
Home Contact Resources Exchange Links ebay