Boutonneuse fever: Description
Boutonneuse fever is also known as Mediterranean fever because it is common throughout the Mediterranean region. It is an infectious disease caused by the bacterium Rickettsia conorii. Diseases caused by this or other rickettsiae are also called rickettsioses after their discoverer, Howard Tayler Ricketts.
All rickettsiae are spread by ticks, fleas, mites, or lice. For the causative agent of boutonneuse fever (R. conorii), ticks serve as vectors (especially the brown dog tick). In fact, the disease is one of the most common tick-borne fevers in southern Europe. In Portugal, for example, 10 out of 100,000 people contract boutonneuse fever every year. It is not uncommon for vacationers from Central Europe to be infected as well. Individual cases of infection have also been recorded in Africa and on the Black Sea.
The term “boutonneuse” comes from the French and can be translated as “spotty” or “button-like”. It describes the blotchy skin manifestations that boutonneuse fever produces.
Boutonneuse fever: symptoms
The lymph nodes near the injection site are often inflamed and palpable enlarged (lymphadenitis).
In addition, those affected develop the eponymous boutonneuse fever: the body temperature rises to over 39 degrees Celsius for about one to two weeks.
On the third to fifth day of illness, a coarse-spotted rash (maculopapular exanthema) develops . Together with the fever it disappears again, leaving no traces (such as scales or scars).
The typical symptoms of Boutonneuse fever are often accompanied by headache, joint pain and muscle aches.
Boutonneuse fever: complications
Infection with the causative agent of boutonneuse fever activates the immune system in the body. As a result, the body’s own inflammatory substances (cytokines) may be elevated in the blood and affect the clotting system. Thus, in some people with boutonneuse fever, blood clots form that block vessels – for example, in the form of deep vein thrombosis in the legs.
Boutonneuse fever: Causes and risk factors.
Boutonneuse fever is caused by the bacterium Rickettsia conorii. This bacterium lives as a parasite primarily in ticks, which in turn live in the fur of rodents or dogs. In the Mediterranean region, up to 70 percent of dogs are infected with ticks. About every tenth tick carries rickettsiae.
If vacationers take such dogs home (to Germany, Austria, Switzerland, etc.), rickettsiae can be introduced. The ticks can be transmitted from the dogs to humans. Fortunately, this rarely happens, as this type of tick prefers to infest dogs. However, they can survive for years in homes and repeatedly cause boutonneuse fever in humans.
Boutonneuse fever: examinations and diagnosis
The right contact person for boutonneuse fever is a specialist in internal medicine with the additional title of infectiology. A tropical medicine specialist is also familiar with this clinical picture. However, in the case of the typical symptoms of fever and skin rash, those affected usually first consult their family doctor. He can also initiate the necessary examinations.
The first step in establishing a diagnosis is to take a medical history. For this purpose, the doctor will ask you various questions such as:
- Do you have any other symptoms? If yes, which ones?
- Do other people in your vicinity suffer from similar symptoms?
- Have you noticed a bite mark or a conspicuous area on the skin?
- Are you aware of any tick infestations on pets in your area?
- Have you recently been abroad, especially in Mediterranean areas?
- Have you had close contact with rodents or dogs from these regions?
The doctor will then take your body temperature, examine all of your skin, and palpate the lymph node regions. If Boutenneuse fever is suspected, he will take a tissue sample from a conspicuous area of skin. In the laboratory, this can be examined for the genetic material of the pathogens using polymerase chain reaction (PCR).
It is also possible to detect the pathogen’s genetic material by PCR using a blood sample from the patient. In addition, the blood can be tested for antibodies to rickettsiae. However, such antibodies can only be found several days after infection.
Blood tests also help to rule out other disease with similar symptoms.
Boutonneuse fever: Treatment
Boutonneuse fever is treated with the antibiotic doxycycline. Affected people must take one tablet twice a day for two to seven days.
Boutonneuse fever: course of the disease and prognosis
In most cases, boutonneuse fever is mild. All symptoms of the disease subside within about two weeks and leave no sequelae. Especially if the disease is diagnosed in time and treated with an antibiotic, complications occur very rarely. They are most likely to develop in the elderly, alcoholics and diabetics. In them, internal organs such as the brain may be more easily affected. In one to five percent of cases, Boutonneuse fever is fatal.
Boutonneuse fever: Prevention
In the case of boutonneuse fever, prophylaxis consists of protecting oneself from tick bites. Precautions should be taken especially when in close contact with possibly infected rodents and dogs in Mediterranean areas, around the Black Sea, in Siberia, India, Central and South Africa.
- Wear closed-toe shoes with a high leg and long pants tucked into your socks. This gives ticks no opportunity to reach an exposed area of skin on their feet or legs. Transmission is not possible through clothing.
- Anti-tick sprays – sprayed on clothing or wrists – also keep the bloodsuckers away.
- If you have a dog, you should put a tick collar on it. This reduces the risk of your dog catching infected ticks – which could then infect you with Boutonneuse fever.
