Q fever (Query fever, goat flu) is a disease that is particularly prevalent in cattle, sheep and goats. It is caused by the bacterium Coxiella burnetii. The pathogen can also be transmitted to humans. The infection is often asymptomatic or similar to influenza and is treated with antibiotics. Read all about symptoms and treatment for Q fever here.
Q fever: description
Q fever is a so-called zoonosis. These are diseases that can be transmitted from animals to humans. The causative agent of Q fever is a bacterium that likes to stay in dust or hay.
Since the Q fever was first diagnosed in 1937 in the Australian state of Queensland with workers in slaughterhouses, the disease was first called Queensland fever. Q fever is widespread around the world. Epidemics with hundreds of illnesses occur mainly in rural areas or on the outskirts, because animals and humans live here more closely together.
Q fever: symptoms
The infection usually begins with the inhalation of the pathogen into the lungs. After about one to three weeks, the first symptoms appear. However, in 60 percent of cases Q fever is without signs of illness.
The first phase of the disease
The symptoms of Q fever are similar to those of influenza. High fever, chills, muscle aches and severe headaches are common complaints. Sometimes the lungs, the liver, the heart or the brain become infected. The disease lasts about two weeks and heals on its own. Pregnant women are at risk of miscarriage, especially in the first trimester of pregnancy. In addition, the pathogen can be transferred to the child.
Chronic course
Very rarely, the disease does not heal on its own. Phagocytes of the immune system pick up the pathogen but can not kill it. The pathogen often remains inactive for a long time in the phagocytes, waiting for a chance to reactivate. When the immune system is weakened by pregnancy or other causes, the pathogen may re-spread in the body. The infection is chronic.
Especially the heart is often affected by a chronic infection. If the heart valves are already affected, Coxiella burnetii can infect the endocardium and heart valves. Sometimes that happens only years after the actual Q fever illness. In rare cases, chronic bone, lung and liver infections can occur. Particularly common are diseases in pregnancy chronic.
Q fever: causes and risk factors
The Q fever is triggered by the pathogen Coxiella burnetii. The bacteria are very resistant to chemical and physical influences. They can survive in dust, hay and other dry materials for up to two years.
A pathogen from the farm
Particularly at risk of developing Q fever are people who have close contact with animals. These include, for example, butchers, animal skin processors, pet owners or veterinarians.
Many animals can become infected with the virus of Q fever. Coxiella burnetii is transmitted via ticks as an intermediate host to cattle, sheep or goats, but also to cats, dogs, rabbits or wild animals.
The bacteria in the dust can be carried away by the wind up to two kilometers and infect humans. Therefore, it is possible that a diseased animal population also infects the inhabitants of the area. Mostly, the disease is mild in humans.
How does the human become infected?
In most cases, the animals become infected through direct contact with the bacteria, for example in the hay. Occasionally, however, Coxiella burnetii is carried on ticks. In this case, the tick settles on the fur of an animal and releases infected feces there. Over this the bacteria reach the affected animal. The infected animals then excrete the bacteria via faeces, urine or milk.
If a person has contact with sick animals, there is a risk of becoming infected. However, he can also become infected by inhaling the highly infectious dust. Already ten inhaled bacteria are enough to trigger a Q fever disease in humans.
A direct infection from person to person is rare, but possible. In addition, in a pregnant woman, the pathogen can pass through the placenta and infect the unborn child.
Q fever: examinations and diagnosis
Since the symptoms of Q fever can resemble many other diseases, the diagnosis is not easy to make. Therefore, the history of those affected is crucial. The doctor could ask the following questions:
- Do you have fever? If so, how long has this been? What is the temperature?
- Do you have a headache or muscle ache?
- Do you keep pets or do you have to deal with animals professionally?
To confirm the suspicion of Q fever, a laboratory examination is carried out. One takes blood from the patient to determine if certain antibodies to Coxiella burnetii can be found. The blood test also shows whether the disease has already taken a chronic course.
Q fever: treatment
Q fever is treated with the antibiotic doxycycline for two to three weeks. Since doxycyline is metabolised via the liver, the liver values are checked by means of blood tests during therapy. Some patients, for example, who have a previous illness, need more medication for treatment. Pregnant women are treated with a special drug (trimethoprim) because doxycycline should not be taken during pregnancy.
Q fever: disease course and prognosis
Most Q fever infections heal on their own after one to two weeks. Sometimes, sufferers but still suffer for weeks under a general fatigue. In very rare cases, the immune system can not completely fight the pathogen and the disease breaks out again after years.
Prevent Q fever
The risk of Q fever is increased in people working with sheep, cattle or animal products such as meat, milk or wool. In Germany vaccination against Q fever is not allowed. In some countries it is available for occupationally exposed personnel such as veterinarians, laboratory and abattoir workers.
The pathogen is killed by heating milk or frying meat. If a pregnant woman Q fever sick and gives birth, the helping staff has to comply with strict hygiene measures.