Fine-needle aspiration findings of the liver in a case of Q fever

Acute Renal Failure Associated with Rhabdomyolysis in Acute Q Fever

The clinical presentation of Q fever is polymorphic and non-specific, and it may be presented as an acute or chronic disease. Renal complications of acute Q fever such as acute glomerulonephritis are not uncommon. Acute renal failure induced by rhabdomyolysis in acute Q fever has until now never been reported in the literature. We presented a case of acute Q fever associated by extreme rhabdomyolysis and consecutive acute renal failure. A male patient was treated with doxycycline and continuous venovenous hemodiafiltration. After two weeks of treatment, the patient completely recovered kidney function, and there were no clinical abnormalities. Acute Q fever must be considered as a possible cause of rhabdomyolysis and acute renal failure. The continuous venovenous hemodiafiltration may be effective, and it seems to be the treatment of choice in severe rhabdomyolysis and consecutive acute renal failure.

Q fever in humans and animals in the United States

Coxiella burnetii, the etiologic agent of Q fever, is a worldwide zoonotic pathogen. Although Q fever is present in the United States, little is known about its current incidence or geographic distribution in either humans or animals. Published reports of national disease surveillance, individual cases, outbreak investigations, and serologic surveys were reviewed to better characterize Q fever epidemiology in the United States. In national disease surveillance reports for 1948-1986, 1,396 human cases were reported from almost every state. Among published individual case reports and outbreak investigations, occupational exposures (research facilities, farm environments, slaughterhouses) were commonly reported, and sheep were most frequently implicated as a possible source of infection. In studies conducted on specific groups, livestock handlers had a significantly higher prevalence of antibodies to C. burnetii than did persons with no known risk. Animal studies showed wide variation in seroprevalence, with goats having a significantly higher average seroprevalence (41.6%) than sheep (16.5%) or cattle (3.4%). Evidence of antibody to C. burnetii was reported among various wild-animal species, including coyotes, foxes, rodents, skunks, raccoons, rabbits, deer, and birds. This literature review suggests that C. burnetii is enzootic among ruminants and wild animals throughout much of the United States and that there is widespread human exposure to this pathogen. Sheep and goats appear to be a more important risk for human infection in the United States than cattle or wild animals, and research studies examining the natural history and transmission risk of Q fever in sheep and goats in this country should be encouraged.

Current laboratory diagnosis of Q fever

Q fever is a worldwide zoonosis caused by the strictly intracellular bacterium Coxiella burnetii. Among symptomatic patients (one-half of patients remain asymptomatic), acute Q fever most frequently manifests as a self-limited febrile illness, pneumonia, or hepatitis. Endocarditis is the predominant form of chronic Q fever. All the classical techniques of bacteriology may be used for diagnosis of C burnetii infection. Nonetheless, because of the risk of contamination, isolation must be performed in biosafety level 3 laboratories. Moreover, to date no diagnostic tests for detection by polymerase chain reaction or specific antibodies for immunochemistry are available commercially. Hence, Q fever is diagnosed in most cases by serology. The most reliable technique appears to be micro-immunofluorescence, which exhibits both good sensitivity and specificity. A wider use of this serology in cases of blood culture-negative endocarditis, atypical pneumonia, unexplained fever, and hepatitis should lead to an increase of diagnosed cases.

Q fever

Q fever is a zoonosis with a worldwide distribution with the exception of New Zealand. The disease is caused by Coxiella burnetii, a strictly intracellular, gram-negative bacterium. Many species of mammals, birds, and ticks are reservoirs of C. burnetii in nature. C. burnetii infection is most often latent in animals, with persistent shedding of bacteria into the environment. However, in females intermittent high-level shedding occurs at the time of parturition, with millions of bacteria being released per gram of placenta. Humans are usually infected by contaminated aerosols from domestic animals, particularly after contact with parturient females and their birth products. Although often asymptomatic, Q fever may manifest in humans as an acute disease (mainly as a self-limited febrile illness, pneumonia, or hepatitis) or as a chronic disease (mainly endocarditis), especially in patients with previous valvulopathy and to a lesser extent in immunocompromised hosts and in pregnant women. Specific diagnosis of Q fever remains based upon serology. Immunoglobulin M (IgM) and IgG antiphase II antibodies are detected 2 to 3 weeks after infection with C. burnetii, whereas the presence of IgG antiphase I C. burnetii antibodies at titers of >/=1:800 by microimmunofluorescence is indicative of chronic Q fever. The tetracyclines are still considered the mainstay of antibiotic therapy of acute Q fever, whereas antibiotic combinations administered over prolonged periods are necessary to prevent relapses in Q fever endocarditis patients. Although the protective role of Q fever vaccination with whole-cell extracts has been established, the population which should be primarily vaccinated remains to be clearly identified. Vaccination should probably be considered in the population at high risk for Q fever endocarditis.