What Is Q Fever?

In most cases Q fever runs without complications. But sometimes serious symptoms can arise. You could develop hepatitis, pneumonia, endocarditis, or meningitis, among other things.

Q fever  is caused by a bacteria that is transmitted from animals to humans. The disease was first identified in Australian slaughterhouse workers in 1937. That’s why it was initially called Queensland fever, but it is a pathology that is common around the world. Another explanation of the designation can be found in the initially unknown cause: “Q” also stands for the English word “query”, ie for “question” in the sense of “questionable” or “doubtful”.

Various researches have clarified  that Q fever is caused by the bacterium  Coxielle burnetii  . This bacterium initially settles in farm animals such as cows, goats, sheep or other mammals. However, it does not cause any health problems in animals.

Although this disease can occur at any time of the year, observations have shown that it occurs particularly in spring and the first few summer months. The peak of the spread is reached between April and May. 

Q fever: causes

Q fever is usually a mild illness with flu-like symptoms. But there is also a deadly form that causes brain damage and attacks the heart, liver and lungs. In some cases, the disease is asymptomatic.

The causative bacterium Coxiella burnetii  is particularly present during the birth of animals,  specifically in the placenta and in the amniotic fluid. The milk, urine and stool of animals are also often infected with it.

In some cases, infection can occur without direct contact with the infected animal. This is the case, for example, if you inhale contaminated air with stool particles, urine or amniotic fluid. The bacteria can also be transmitted through consumption of unpasteurized milk obtained from infected animals.

Q fever: characteristics and symptoms

It is estimated that only half of those infected have symptoms. These usually present themselves two to three weeks after contact with the causative bacteria. The most common signs of this include:

• Fever with chills and sweats
• Headache and muscle pain
• Nausea, vomiting and / or diarrhea
• Tiredness and exhaustion

• Chest and / or abdominal pain
• Dry cough
• Weight loss

All of these symptoms can be mild or serious. If the bacteria infest the lungs or liver, pneumonia or hepatitis can occur. Pregnant women need to be especially careful because the disease could trigger a miscarriage.

Only 5 percent of people with Q fever develop a chronic clinical picture. In this case, the symptoms can manifest themselves for months or even years after the infection. It’s a serious problem that can be fatal. Because in this case one heart valve (or several) is often infected.

Risk factors

Some farm animals or pets are infected with this bacterium,  but wild animals and, for example, ticks can also be carriers. The most important risk factor is therefore direct or indirect contact with infected animals.

Therefore there is logically a higher risk for people who breed animals or work in a slaughterhouse. Veterinarians, researchers and people who work in the processing of animal foods are also more likely to get sick. It has also been shown that men are more prone to this than women.

In most cases, people between the ages of 30 and 70 will get Q fever. It rarely happens in childhood. However, if a child develops Q fever, they will usually experience symptoms of pneumonia.

Other dates of interest

The risk of chronic disease progression is much higher in the following situations: 

• If you already have a disease of the heart valves,
• if there are abnormalities in the blood vessels,
• when the immune system is weakened
• and in pregnant women.

No vaccination against Q fever is currently  available. It is therefore important to take precautionary measures to prevent contact with the causative bacteria. In general, the consumption of unpasteurized animal milk should be avoided.

People who work with animals or animal products  should also consider possible symptoms and get examined if necessary. Those who are in a particularly vulnerable risk group should avoid contact with animals.