Q Fever

About

Q Fever takes its origin from word "query" and is caused by bacteria Coxiella burnetii that infects some animals and is passed on to humans due to inhalation of infected air particles.

Q Fever is a worldwide zoonotic disease caused by, a bacterium called Coxiella burnetii. It was first identified in Queensland, Australia, in 1935 by Derrick. A zoonotic disease is an animal disease that can be transmitted to humans. Cattle, sheep, and goats are the primary reservoirs of C. burnetii. Pets (cats and dog) are common sources of infection. Milk, birth products, urine, and feces of infected animals contain the disease-causing organisms that are resistant to heat, drying, and many common disinfectants. This resistance allows bacteria to survive for long periods in the environment. Humans are usually infected by inhalation of aerosols or infected air particles. Coxiella can be spread far through the air. Exposure to milk products is a less frequent source of infection.

Spread from human to human (though extremely rare) can occur through sexual intercourse, during delivery, or by blood transfusion. Q Fever is partially seasonal and often related to lambing time.

Males have more severe disease. Middle-aged people are more frequently affected and hospitalized. Only about 50 percent of all people infected with C. burnetii show features of clinical illness. Indirect immunofluorescence assay (IFA) is the most dependable and widely used method to detect Q Fever. Diagnosis of Q Fever is made based on laboratory investigations. Doxycycline is the most efficient antimicrobial for Q Fever.

Q Fever is considered by the CDC (Centers for Disease Control and Prevention) to be a potential agent of bioterrorism. As the Coxiella burnetii is highly resistant to heat and drying, it can survive for long periods in the environment and can be used in biological warfare.

References:

1. Cecil Medicine, 23^rd ed.
2. Harrison's PRINCIPLES OF INTERNAL MEDICINE, Seventeenth Edition.