Hantavirus

Hantaviridae

Profile

Hantaviruses are enveloped single-stranded RNA viruses that can be transmitted to humans through the excretions of certain rodents such as mice or rats. Various species occur worldwide, whose distribution depends on the distribution of their host animals and cause infections with different courses of disease. In Central Europe, the most common species are Puumala virus (PUUV) and Dobrava-Belgrade virus type Kurkino (DOBV type Kurkino).

Occurrence

Hantaviruses occur worldwide.

Pathogen reservoir

Hantavirus is transmitted by small mammals such as mice or rats. PUUV is usually transmitted by the bank vole, DOBV type Kurkino by the fire vole. Hantaviruses have also been detected in shrews, bats and moles, but the exact role of these hosts is unclear.

Infection route

Infected animals excrete hantaviruses via saliva, urine and faeces. Infection occurs through inhalation of virus-containing aerosols, fine airborne liquid particles, through bites or through contact of open skin areas with materials such as dust or soil in which virus particles are deposited. Hantaviruses can also be transmitted by ingesting contaminated food.

Depending on the environmental conditions, hantaviruses can survive for several days outside a host animal and remain infectious. Human-to-human transmission is only considered a possibility for highly contagious hantavirus strains from South America.

Incubation period

Usually two to four weeks. In some cases only five days, in others up to 60 days.

Symptomatology

Infections often run asymptomatically or with non-specific general symptoms such as a feeling of fatigue. In symptomatic courses, the symptoms differ depending on the virus species.

The species found in Europe, Asia and parts of Africa cause febrile illness in humans with bleeding and damage to kidney function. Accompanying inflammation of the heart muscles, the thyroid gland or the central nervous system can also occur. Infections with the hantavirus species that occur frequently in Central Europe can have a milder course, in which the kidneys are mainly affected. This is called nephropathia epidemica.

The species found in North and South America cause a clinical picture characterised by damage, especially to the lungs and heart.

Mortality differs greatly between the different species.

Therapy

The therapy of hantavirus disease focuses on symptomatic treatment. If necessary, intensive medical treatment is required to treat bleeding, stabilise the circulation, treat acute kidney damage and, in the case of acute respiratory insufficiency, to provide mechanical ventilation. There is currently no causal therapy available.

Prevention

The most important measure to prevent hantavirus infection is exposure prophylaxis, i.e. avoiding contact with rodent excreta. Food should be stored safely to avoid attracting the animals. In the vicinity of human living areas, rodents should be additionally controlled.

Protective measures such as the wearing of respirators and gloves should be observed when coming into contact with dead rodents or in contaminated places where mice are present. Mouse carcasses and droppings should be wetted with a commercial cleaning agent before disposal.

Situation in Austria

As of 10.10.2023, 85 cases of hantavirus have been reported in Austria for the year 2023.

Subject information

Symptoms

Hantaviruses, which are found in Europe, Asia and parts of Africa, cause haemorrhagic fever, a febrile illness accompanied by severe bleeding, and concomitant kidney damage in those affected. The disease progresses in three phases: In the first phase, there is a high fever, a strong feeling of flu with headache and pain in the limbs, and bleeding into the skin, mucous membranes and conjunctiva. After about a week, the disease moves into the second phase, which is characterised by a lack of blood platelets and a drop in blood pressure up to circulatory shock. In the third phase, after a total of about nine to twelve days, the function of the kidneys and thus urine production is severely restricted. There is a loss of red blood cells and protein via the kidneys and in some cases an acute respiratory syndrome. If the patient survives this phase of the infection, kidney function often recovers after three to ten days without persistent renal impairment.

Hantaviruses found in North and South America typically cause a hantavirus-induced (cardio-) pulmonary syndrome. Here, too, flu-like symptoms with nausea, vomiting, muscle and abdominal pain occur initially. Bleeding does not occur. The second phase of the disease is characterised by coughing, increased breathing frequency and shortness of breath. The pulmonary circulation becomes overloaded, there is water retention in the lungs and a rapidly progressing respiratory distress syndrome. The mortality rate is 25-40%.

Nephropathia epidemidica is a milder form of progression that can occur after infections with Puumala viruses and the Dobrava-Belgrade virus type Kurkino. The course can be divided into two phases, the first of which is characterised by fever, colicky, often unilateral flank pain, nausea, diarrhoea, neck stiffness and visual disturbances and is rarely accompanied by bleeding. In the second phase, there is interstitial nephritis with an increase in CRP and leukocytes, tubular proteinuria, microhaematuria and thrombocytopenia.

The mortality of PUUV infection is <0.1%, that of DOBV type Kurkino is 0.3-0.9%. Other DOBV variants can cause severe courses of disease with a lethality of up to 15%.

Diagnostics

The diagnosis is usually made serologically by detecting specific IgM and IgG antibodies by enzyme-linked immunosorbent assay (ELISA), immunoblot or by indirect immunofluorescence (IFA). IgM antibodies can usually be detected at the onset of the diseases.

Therapy

The effectiveness of early antiviral chemotherapy with ribavirin is discussed among experts. In severe pulmonary manifestations, the bradykinin receptor antagonist Icatibant has been used successfully in off-label use.
For more information, see rki.de.

Contact

You can find the responsible reference centre under the following link:
https://www.sozialministerium.at/Themen/Gesundheit/Uebertragbare-Krankheiten/Statistiken-und-Fallzahlen.html

Last updated: 15.02.2024

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