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 cats and dogs. The infection results from inhalation of a spore-like small-cell variant, and from contact with the milk, urine, feces, vaginal mucus, or semen of infected animals. Rarely, the disease is tick-borne. The incubation period can range from . Humans are vulnerable to Q fever, and infection can result from even a few organisms. The bacterium is an obligate intracellular pathogenic parasite. Signs and symptoms The incubation period is usually two to three weeks. The most common manifestation is flu-like symptoms: abrupt onset of fever, malaise, profuse perspiration, severe headache, muscle pain, joint pain, loss of appetite, upper respiratory problems, dry cough, pleuritic pain, chills, confusion, and gastrointestinal symptoms, such as nausea, vomiting, and diarrhea. About half of infected individuals exhibit no symptoms. During its course, the disease can progress to an atypical pneumonia, which can result in a life-threatening acute respiratory distress syndrome, usually occurring during the first four to five days of infection. Less often, Q fever causes (granulomatous) hepatitis, which may be asymptomatic or become symptomatic with malaise, fever, liver enlargement, and pain in the right upper quadrant of the abdomen. This hepatitis often results in the elevation of transaminase values, although jaundice is uncommon. Q fever can also rarely result in Retinal vasculitis.