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Q Fever


Q fever, also known as query fever, is an infection caused by the bacterium Coxiella burnetii. This infection usually presents with mild symptoms that resemble flu. Many people who carry this bacteria may remain asymptomatic for a long time. This bacteria is commonly found in sheep, cattle, and goats. People working with these animals should take special precautions against this infection. Long-term Q fever can lead to serious complications of multiple organs. 


The causative bacterium is Coxiella burnetii. The infectious potential of this bacterium is so high that even if a single bacteria enters your system, it can cause Q fever. For this reason, it is also one of the most infectious diseases in the world. The bacteria is found in domestic mammals like sheep, goats, etc. Pet animals like cats, dogs, and rabbits can also carry this bacteria.

The infection occurs either due to inhalation of contaminated particles or coming in contact with milk, urine, feces, semen, or vaginal discharge of these animals. The incubation period for this bacteria lasts for 4 – 90 days. During this period, this bacteria replicates itself and grows in number. This infection cannot spread from one person to another. 

Risk Factors And Epidemiology

Q fever is more prevalent among people who work with these animals or live close to a farm. Farmers are at high risk because their occupation makes them exposed to the causative agent at all times. Veterinary doctors, livestock farmers, and animal researchers are at increased risk. If you live close to a farm or travel through such an area, you may be at risk because the air can contain contaminated dust particles. The risk of chronic Q fever is higher in those with weak immune systems, heart valve disease, blood vessel abnormalities, or kidney impairment.

Q fever is predominant among males and elders. It can occur at any time throughout the year, but it peaks during mid-year months. It can also develop in children and presents like pneumonia if the infection progresses for an extended period. 

Signs And Symptoms

Because the incubation period of this bacteria is long, many people don’t show any symptoms for two to three weeks even after getting contaminated. Once the bacteria become active, you may develop mild symptoms including fever, headache, chills, cough, tiredness, nausea/vomiting, diarrhea, and abdominal pain. If your symptoms do not get well within 2 to three weeks, you will need to consult a healthcare expert. The presence of a heart valve disease can increase the risk of endocarditis if this infection is left untreated. 


Q fever is difficult to diagnose based on its symptoms alone because it resembles other respiratory illnesses. Your doctor will need your history, occupation, area of residence, recent travels, and a few other details to suspect Q fever. A blood antibody test can be done to confirm the diagnosis. However, this test may come negative in the first few days of infection. If chronic Q fever is suspected, your doctor may ask for a chest x-ray or echocardiogram to visualize the condition of your heart and lungs. 


Mild Q fever does not require any treatment, and the symptoms fade away within two to three weeks. Severe form of Q fever is treated with the use of antibiotics. If your body does not respond to antibiotics and symptoms persist, your doctor should look for other possible causes. Patients with chronic Q fever that lasts for around 18 to 20 months are also kept on antibiotics until the infection is completely eliminated. Rest well and drink plenty of fluids to replenish your body and avoid weakness.

The preferred antibiotic for the treatment of Q fever is doxycycline. It is safe for both children and adults. It is to be taken in specific dosages as prescribed by your doctor. The antibiotic treatment can last from 2 to 3 weeks. If you are unable to take doxycycline, your doctor will prescribe an alternative antibiotic for your treatment. 


The overall prognosis of Q fever is good. Most cases recover well without developing any severe symptoms. If chronic Q fever develops, it can affect your heart, lungs, brain, liver, and kidneys. Endocarditis is one of the serious complications of Q fever. Pregnant women may experience miscarriage, premature birth, or stillbirth of a child in case of severe Q fever. 


The primary method of prevention against Q fever is vaccination. A vaccine has been made in Australia for this organism, but it is not available in the United States yet. If you are not vaccinated or work close to domestic mammals, take special precautions to reduce the risk of this infection. Wash your hands properly after dealing with animals. Discard the waste or birth products of animals safely while wearing gloves. The air should be regularly decontaminated to kill the bacteria in air particles. Always drink pasteurized milk and use pasteurized milk products. Pasteurization kills harmful bacteria and organisms in milk to decrease the risk of all possible infections. Infected animals should be kept separate until they have recovered.

Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 27, 2023.



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