Q fever(redirected from nine mile fever)
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Q fever,disease caused by Coxiella burnetii, a small, Gram-negative bacterium. The bacterium infects livestock (cattle, goats, and sheep) and other domesticated animals, and is found in the urine, feces, amniotic fluid and other birth products, and milk of infected animals. It is typically transmitted to humans by inhalation of contaminated dust particles or from contaminated materials; Q fever is an occupational hazard among dairy farm and slaughterhouse workers. C. burnetii infection does not produce symptoms in roughly half of all cases involving humans, and most symptomatic cases involve fever, chills, fatigue, and other flulike symptoms, making Q fever difficult to diagnose. Severe cases may lead to inflammation of the lungs (pneumonia) or liver (hepatitis), and in pregnant women the disease may cause miscarriage, premature birth, or other complications. A small number of infected persons develop chronic Q fever, which is serious and can be fatal. Most people with acute Q fever recover without treatment or after treatment with the antibiotic doxycycline. Chronic cases are treated with a combination of antibiotics including doxycycline and hydroxychloroquine, and treatment lasts for several months.
Australian Q fever (from the first letter of the English query, because the nature of the disease was unknown when it was first described), an acute infectious rickettsial disease occurring with fever, primary pulmonary involvement, and an absence of rash.
Q fever is found all over the world. The causative agent is Coxiella burnettii (after the Australian scientist F. Burnet, who described the organism in 1937). In natural foci, marsupials, rodents, dogs, cattle, and other farm animals that excrete the rickettsiae with urine, feces, and milk serve as the reservoir for the organism. The infection is transmitted by many species of ticks and mites. It is also transmitted from animal to man through milk and other infected food products or by dust when working with infected wool, fur, and straw. Infection is also possible in caring for or slaughtering the diseased animals. The incubation (latent) period lasts from two to five days. The disease has an acute onset, with a sudden elevation of body temperature and chills. Severe headache, general weakness, insomnia, muscular pains, and pulmonary foci of pneumonia are also observed. Recovery follows in 12–15 days. Recurrences are possible.
Q fever is treated with antibiotics. It is prevented by checking for its presence in animals and treating infected herds. Persons working on livestock farms or in slaughterhouses should observe the rules of personal hygiene. Vaccination is also a preventive.
The animals susceptible to Q fever include cattle, dogs, horses, camels, swine, poultry, wild birds, and wild animals. The disease is prevalent in Australia and in certain countries of Europe, Asia, and America. In most cases, its course is asymptomatic and benign.
REFERENCESFedorova, N. I. Epidemiologiia i profilaktika Ku-rikketsioza. Moscow, 1968.
Kasatkina, I. L. Ku-likhoradka. Moscow, 1963.
I. I. ELKIN