The little red-eared mouse, a common but inconspicuous representative of the vole, is more dangerous than many believe: it transmits the dangerous hantaviruses. In Germany, the virus is only notifiable since 2001, especially many reported infections occurred in 2007 (1, 688) and 2010 (2, 017). In the record year 2012, 2, 824 cases were reported to the Robert Koch Institute. Afterwards, however, the numbers dropped again; In 2016 there were only 278 reported cases. However, experts estimate that the number of unreported cases is much higher.
What are hantaviruses?
An infection with the Hantavirus can cause a sometimes serious illness. The pathogens belong to the virus group of Bunyaviridae.
The term hantavirus dates back to the time of the Korean War of 1950-53. There several thousand soldiers suffered from the so-called Korea fever, accompanied by internal bleeding and kidney failure. The trigger was the previously unknown hantavirus, which was named after the Korean river Hantaan, on which the onset of the serious illness began.
The pathogens are spread worldwide today. Especially in Southeast Asia hantaviruses are common pathogens. But even in Europe, the infectious disease is not uncommon.
Symptoms of hantavirus infection
If you have flu-like symptoms for more than three days, you may have been infected with Huumavirus type Puumala. Especially characteristic for hantavirus infection are signs such as:
- high fever over 38 degrees Celsius
- a headache
- stomach pain
- back pain
- possibly a conjunctivitis
- Blood in the urine
Disease course of an infection with hantaviruses
The majority of viral infections go unnoticed, that is, the disease is asymptomatic or so easy that the infection does not strike the person concerned.
A severe course, that is, diseases with pronounced symptoms, is summarized by the term "hemorrhagic fever with renal syndrome" (HFRS): in the worst case, this means that the kidney function is disturbed or the kidneys fail. Besides, the liver is enlarged. In exceptional cases, it can lead to a life-threatening bleeding tendency.
Transmission of hantaviruses
An increased occurrence of hantavirus infections is usually associated with a high increase of rodents. The natural hosts of hantaviruses are mice and rats. The viruses are secreted by infected mice via saliva, urine and feces. The main vectors in Central Europe are the red-eared mouse, firefly and brown rat. Transmission from human to human or infection via pets and insects is unlikely.
The Puumalavirus spreads whenever the number of red chickens increases - this is the case when there is plenty of food. Particularly at risk are people who spend a lot of time outdoors, such as foresters, forest workers, farmers, mushroom and berry pickers, but also guests and owners of forest-near apartments that have stood empty for a long time.
Because the virus is transmitted via urine and feces, dried dusty feces, which are whirled up when sweeping, can enter the respiratory tract. The same thing can happen if you collect or split wood, or clean dandruff, garages, and basements where the small rodents with their reddish fur have settled.
Diagnosis of hantavirus infection
The group of hantaviruses includes about 30 serotypes. These are distinguishable variations of bacteria or viruses. In Central and Northern Europe, the Puumala virus, named after the Finnish city of Puumala, where this type first appeared, is mainly distributed.
Hantaviruses are detected by antibodies in the patient's blood. Special tests in laboratories reveal which serotypes are involved. According to the German Green Cross, only 60 to 70 percent of patients in the acute phase develop detectable, specific antibodies.
The problem is that due to the low level of awareness of hantavirus infections among doctors in Europe, the diseases sometimes even confused with cecal and hepatitis or misjudged as "kidney failure of uncertain origin" or severe flu.
Treat an infection with hantavirus
There is no vaccine against hantaviruses yet. At most, a disease can be treated symptomatically: If, for example, pain or fever occurs, they can be alleviated with medication.
The doctor treats severe cases with ribavirin, which is used inter alia in AIDS and hepatitis C, as it inhibits virus proliferation. If a hantavirus infection is detected, it must be reported to the responsible health department.
Prevention of hantavirus infections
As a preventive measure, the Robert Koch Institute recommends that when cleaning long unused rooms, where mice are frequented - such as barns, attics, garages, storage rooms, workshops, but also terraces - a lot to note:
- Ensure adequate ventilation and wear respiratory protection when cleaning.
- Clean with damp cloths to stir up as little dust as possible.
- Spray feces with disinfectant.
- Wash your hands thoroughly after cleaning.
Dead mice should not be touched with their bare hands, but with disposable gloves. It should be sprayed with a disinfectant, put in a plastic bag and sealed with another plastic bag well, then you can dispose of them with the household waste.