Questions & Answers

Q fever (query fever), also commonly referred to as coxiellosis when it occurs in animals, is a disease caused by the bacterium Coxiella burnetii. Coxiella burnetii can infect humans as well as animals. Usually the pathogen is transmitted from animals to humans – therefore Q fever is a zoonosis.

• Humans (acute Q fever):

Almost all infections in humans manifest as acute Q fever. Due to the unspecific symptoms acute Q fever can easily be confused with a common cold. About 1 to 3 weeks after infection clinical symptoms may occur in about 40 % of the infected individuals. These symptoms include:

- Fever
- Muscle aches und chills
- Severe headaches, often behind the eyes
- Fatique

In about 10 % of the cases patients suffer from atypical pneumonia (inflammation of the lungs) and/or granulomatous hepatitis (inflammation of the liver). Very rarely, the infection results in myocarditis (inflammation of the heart muscle), pericarditis (inflammation of the pericardium, the protective sac surrounding the heart) or meningoencephalitis (inflammation of the brain and its meninges). Important: If there is any clinical suspicion of endocarditis (which among others manifests in changes of the cardiac valves, subfebrile temperature), the possibility of chronic Q fever should always be kept in mind and definitely be checked (see also Category: Long-term Health Complications: What is chronic Q fever?).

• Animals (Coxiellosis):

In particular, ruminants (cattle, sheep, goats) shed the pathogen via birth fluids, milk and faeces. Symptoms may vary considerably.  Especially sheep and cattle infected with Coxiella burnetii appear healthy. Pregnant goats, however, often experience abortions late in pregnancy. In general, the following symptoms may be associated with Q fever in ruminants:

- Abortion
- Stillbirth
- Delivery of weak offspring (lambs, calves)
- Delayed expulsion of the afterbirth

• Humans

Humans mainly get infected by inhaling dust or airborne droplets containing the bacterium Coxiella burnetii when having direct or indirect contact with infected sheep, cattle and goats as well as their excretions. Pets (dogs, cats) and wildlife can also become infected and shed the pathogen, even though a transmission to humans has  rarely been reported. A larger quantity of the infectious pathogen is shed together with birth fluids and the afterbirths of infected ruminants. Even if an infected herd is located several kilometres away, there is still a chance of infection if dust carrying the pathogen is spread through the air. The germ can also be transmitted when  ruminants are slaughtered. However, there is no risk from eating thoroughly cooked meat. The risk of infection from drinking raw milk and eating raw milk products is considered low, but in principle it is possible. (Statement No 018/2010, of 15  March 2010, in German, from the German Federal Institue of Risk Assessment (Bundesinstitut für Risikobewertung (BfR)). The pathogen is inactivated by pasteurisation.

• Animals

Animals are also infected mainly by inhaling dust or airborne droplets containing the pathogen. In particular, the acquisition of infected animals or the presence of other herds/flocks nearby as well as other pets e.g. cats can be the reason for introducing the germ. C. burnetii can also be transmitted by mating. In practice, it is often not possible to fully trace the origin of an infection. Recent scientific studies have shown that infection with C. burnetii has resulted in subsequent shedding of the pathogen with birth fluids and afterbirths only in the case of pregnant goats. Infection of non-pregnant animals does not seem to lead to the shedding of C. burnetii in a subsequent pregnancy. So far there has been no conclusive evidence whether other pets (e.g. cats) and ticks transmit C. burnetii. However, above all tick faeces are thought to play an essential role in spreading the pathogen. Infected ticks shed large quantities of the pathogen together with their faeces.

• Humans

Q fever is diagnosed by serological testing i.e. testing for antibodies against Coxiella antigens.

• Animals

The most sensitive test for diagnosing Q fever is the molecular biological analysis (PCR) of afterbirth products, dead lambs/calves or vaginal swabs which detects the genetic material (DNA) of the pathogen. The PCR test can detect the instantaneous shedding of Coxiella burnetii. Serological testing for antibodies against Coxiella antigens does not reliably detect an acute infection, but does reflect a recent infection.

• Humans

Q fever in humans is a notifiable disease accotding to the German Infection Protection Act (Infektionsschutzgesetz (IfSG)). According to § 7 Section 1 IfSG, direct or indirect detection of Coxiella burnetii indicating an acute infection is reported by name to the local health authorities.

• Animals

In Germany, Q fever or the detection of C. burnetii in ruminants is a notifiable disease under the German Regulation on Notifiable Animal Diseases (Verordnung über meldepflichtige Tierkrankheiten (TKrMeldpflV)). At the same time the heads of the Veterinary Investigation Offices (Veterinäruntersuchungsämter), the local animal health agencies (Tiergesundheitsämter) or other public or private veterinary medicine research facilities as well as veterinarians identifying notifiable diseases while carrying out their professional activities are obliged to immediately report the occurrence of the disease or the pathogen to the authority responsible under federal state law stating the date of detection, the animal species concerned, the herd/flock concerned, the district and the district town.

• Humans

According to the Annual Report 2018 of the Robert Koch Institute there are significant variations in the number of acute diseases that have been reported since 2001. The cases reported vary between 86 and 416 per year (average number of 233 infections). Due to the known mild symptoms of acute Q fever an underreporting of cases can be assumed.

• Animals

According to the Animal Health Annual Report 2018 of the Friedrich-Loeffler-Institut between 146 and 309 infections (average number of 225 infections) with C. burnetii were reported annually in animals or herds between 2014 and 2018. An infection with C. burnetii in animals may occur without obvious symptoms, therefore an underreporting of cases can be assumed.

• Humans

Acute Q fever is treated with antibiotics with antibiotic treatment lasting 14 days and the respective antibiotic tablets being taken (e.g. doxycycline). Children the age of 8 and pregnant women (see section Pregnancy and Breastfeeding) have to be sometimes be treated with antibiotics from other substance groups (e.g. macrolide). It is very important for children to adapt dosing to the child’s weight.

• Animals

According to current knowledge, it is not possible to treat animals that shed large amounts of infectious organisms during an outbreak of acute Q fever in a herd with the aim of significantly reducing or even eliminating the number of pathogens. Treatment with oxytetracycline does not lead to a significant reduction of pathogen shedding. Vaccination does not result in a significant reduction of pathogen shedding either. However, vaccination against C. burnetii decreases shedding of pathogens of infected animals in the long run. Animals should be vaccinated prophylactically, in order to prevent acute Q fever events in herds/flocks.

• For vaccination recommendations see section “Where do you find additional information?“ and check for STIKO-Vet.

Acute infection during pregnancy may increase the risk of miscarriage (especially if primary infection occurs in the first trimester), premature birth, placentitis (inflammation of the placenta) which may result in abortion, or low birth weight of the newborn. Transmission of the pathogen in the womb leading to long-term health consequences has not been described, yet.
Pregnant women diagnosed with acute Coxiella burnetii infection should be serologically tested for chronic Q fever after giving birth.

•  (see also section "What is chronic Q fever?")

If there are signs of acute Q fever during pregnancy, pregnant patients must not be given the same antibiotics as healthy women, which means that antibiotics from another drug class (e.g. cotrimoxazol) must be used (NOTE: administration of cotrimoxazole is recommended up to a maximum of 32 weeks' gestation).

Women suffering from acute Q fever are advised not to breastfeed whether or not they have been treated with antibiotics, as the Q fever pathogen may pass into breast milk and taking antibiotics may not completely prevent the bacteria from being passed into breast milk.

In humans acute Q fever very rarely (in about 1 % of the Q fever cases) results in chronification – i.e. an infection which can be detected even after 6 months.

Chronification may cause the following medical conditions:

- Chronic Q fever with among others inflammation of the heart muscle (endocarditis)

• (see also: What is chronic Q fever?)

- Q fever fatigue syndrome (QFS)

• (see also: What is Q fever fatigue syndrome (QFS)?)

In about 1% of cases, an acute Coxiella burnetii infection becomes chronic - i.e. an infection that can still be detected after 6 months. Patients with chronic Q fever often develop endocarditis (inflammation of the heart muscle). The incidence of, for example, granulomatous hepatitis (inflammation of the liver) or osteomyelitis (inflammation of the bone or bone marrow) is much lower. Treatment of chronic Q fever is time-consuming (several years), and if the disease is not treated at all, there is a mortality rate of up to 40% combined with a high complication rate.
Patients of risk groups with already existing diseases or changes in the blood vessels including heart valves, or with severe immunosuppression (suppression of the body's own defence system) have a significantly increased risk for transition into a chronic Coxiella burnetii infection.
The administration of a prophylactic dose of antibiotics for 12 months after an acute disease may prevent the development of chronification in the above-mentioned risk groups.

Treating the chronic infection is time consuming. Therefore, a high degree of self-discipline is required and should be carried out by experienced medical specialists (infectologists). In case of chronification a combined therapy of at least 24 months with e.g. doxycycline and hydroxychloroquine is carried out. Therapy related regular check-ups of antibody levels in the blood are required.
In addition, the amount of the antibiotics doxycycline and hydroxychloroquine administered should be monitored. Besides this, a regular examination of the ocular fundus should be performed, as chloroquine may cause damage of the eyes depending on dosage.

After acute Q fever persistent symptoms as well as impairments in the quality of life can occur which may last 12-24 months.
Most frequent symptoms:
- Fatigue
- Inconveniences in one's everyday activities
- Muscle pain
- Night sweat
- Affected patients often describe that they haven't reachieved performance and working levels even after one year.
Therapeutically this symptomatic complex is a challenge, as the disease can't be influenced by administering antibiotics. In addition, a diagnostic laboratory test for detecting the disease is not possible. Therefore, psychosomatic and behavioural therapeutic rational approaches are recommended.

• Increased abortion rate
• Stillbirths
• Delivery of weak offspring (lambs/calves)
• Accumulation of delayed expulsion of the afterbirth
• Fertility problems and loss of animal performance such as for example significantly longer calving intervals in cows

If your animals show signs of Q fever, please contact your vet who will arrange the necessary laboratory tests to confirm the suspected diagnosis of Q fever.

• Inform your colleagues and family members about the necessary protective and hygienic measures. Serological surveillance to detect and monitor the infection status of animal owner (including their families) is advisable.
• Put up a sign near your stables: "Valuable livestock – Do Not Enter. Authorised Personnel Only.“
• Prevent unauthorised people from getting access to your animals.
• Don’t exhibit animals and don’t offer your animals in auctions.
• Don’t sell any animals to new herds/flocks.
• Don’t offer raw milk or raw milk products to consumers and stand down from drinking raw milk and eating raw milk products. Pasteurisation inactivates the pathogen.
• Store the manure under foil and away from any population for 9 months before spreading it on fields. Spreading the manure should occur on calm days with high humidity. Then the manure should be immediately incorporated into the soil.
• Control rodents.
• Make sure births and shearing occur in closed premises.
• If possible, birth assistance should be carried out by people already having antibodies from a former infection. It is understood that this group of people is less susceptible to a new infection with C.  burnetii.
• Birth assistance should be carried out by taking safety and hygiene measures into consideration i.e. at least disposable gloves for birth, preferably the farm’s own overalls resistant to boiling or disposable protective clothing, the farm’s own wellies or disposable plastic overshoes, FFP3 protective mask, googles or protective visor.
• Collect all after birth material immediately and store it in a closed container until it is disposed of by animal by-products processing plants (rendering plants). The container should be cleaned and disinfected after having been emptied.
• Strict separation of working and leisure clothes. After leaving the livestock clothing has to be changed. Clean and disinfect your working clothes as well as your working material. Wash clothing as hot as possible, and disinfect surfaces with 70% alcohol or peroxyacetic acid. Disinfect your hands with an alcohol preparation.
• Have your herd/flock vaccinated against C. burnetii.
• Tip: Please consult your Animal Diseases Fund (Tierseuchenkasse) for support for vaccination costs.

• For humans:
There is no vaccine for humans in Germany. Worldwide the only approved vaccine for humans is available in Australia.
• For animals:
There is an approved vaccine for cattle and goats in Germany. This vaccine can also be used for sheep (so-called reclassification of vaccines). Information about reclassification of vaccines can be found in „Statement for reclassification of immunological veterinary drugs" of StIKo Vet (work group ruminants) in German.

Download pdf in German

A vaccination schedule should be set up together with your attending vet. Basically, every animal has to have primary immunization first (twice vaccinated at an interval of 3 weeks). Subsequently, an annual booster vaccination is necessary. Depending on the risk of infection such a vaccination schedule may vary, too.

The Animal Diseases Fund (Tierseuchenkasse) of individual Federal States partly or even completely covers the costs for the vaccine and the vaccination by the vet. The conditions for assumptions of costs have to be inquired with the respective Animal Diseases Fund (Tierseuchenkassen) in advance.

• Robert Koch Institute provides additional information in German relating to Q fever in humans here.
• Friedrich Loeffler Institut provides additional information in German relating to Q fever in animals here.
• Visit our subsite "Q Fever a Global Zoonosis" for further information as to the Q fever pathogen Coxiella burnetii and also learn about Q fever in humans and animals.
• The guideline for Q fever Baden-Wuerttemberg provides recommendations for fighting Q fever in small ruminants in Baden-Wuerttemberg. Download the guidelines in German here.
• The recommendations of the Federal Ministry of Food and Agriculture are intended to assist with checking existing hygiene measures. Especially animal owners and other group of persons being in contact with animals (e.g. live stock traders, carriers) should be made aware of necessary hygiene measures. Download the recommendations in German here.
• The „Guideline Biosecurity in Cattle Farming" deals with the analysis of existing risks of disease introduction in animal husbandry as well as the development of measurements to reduce or prevent this risk. Download the guideline in German here.
• The guideline drawn up by the „work group ruminants" of StIKo Vet (Ständige Impfkommission Veterinärmedizin) for vaccination of cattle and small ruminants is a help for decision-making for the applying vet and can be downloaded in German here. Information in German relating to „ reclassification of vaccines " are found here.
• In addition, further information relating to Q fever can be found on the homepage of the interdisciplinary consortium Q-GAPS (Q fever GermAn Interdisciplinary Program for reSearch).