Hospital.Help

Hamburg – Due to West Nile fever, doctors in Germany have recently been confronted with a virus that is transmitted by mosquitoes. The Robert Koch Institute (RKI) registered the first infections in this country in 2019. This year, the RKI has already reported four cases transmitted in Germany (as of September 13). However, most infections are likely to remain under the radar. Jonas Schmidt-Chanasit explained to the German Medical Journal.

5 questions for Jonas Schmidt-Chanasit, Head of the Arbo Department­virology and entomology at the Bernhard Nocht Institute for Tropics­medicine (BNITM)

Which symptoms should lead to West Nile fever being considered in patients?
In most cases, the West Nile virus (WNV) causes only mild symptoms or no symptoms at all. About 20% of those infected develop West Nile fever with non-specific symptoms such as fever, headache or muscle pain.

In rare cases, in about 1% of infections, severe neurological diseases such as encephalitis or meningoencephalitis can occur. Differential diagnosis of encephalitis or meningoencephalitis includes other viral and bacterial pathogens.

What should a doctor do if WNV is suspected?
In cases of suspicion, a PCR test of blood, urine and, if necessary, cerebrospinal fluid should be carried out, as well as serological diagnostics for WNV antibodies (IgM and IgG). A diagnosis cannot be made based on symptoms alone. According to Section 7, Paragraph 1 of the Infection Protection Act, there is a reporting obligation for direct or indirect detection of pathogens.

How should treatment be carried out in suspected cases or after diagnosis?
There is no specific antiviral therapy against WNV. Treatment is symptomatic. In mild cases, symptomatic therapy with fever reduction and painkillers is sufficient. Severe cases, especially neurological complications, often require intensive care.

Should Infected In case of suspicion or after diagnosis, isolate or sleep under a mosquito net so as not to endanger family members, for example?
No, that is not necessary. Direct human-to-human transmission is not possible – except through blood transfusion or transplantation. And mosquitoes transmit the virus from birds to humans, but not between two people. This is because humans are what is known as a false host for WNV and the viral load is not high enough for mosquitoes to absorb it in sufficient quantities to then pass it on.

So far, WNV acquired in Germany has been isolated cases. Do you expect WNV to become a common infectious disease in Germany in the medium or long term?
Given climate change and the nationwide spread of mosquito vectors, it can be assumed that WNV will continue to spread in Germany in the coming years. However, whether there will be a significant increase in cases depends on various factors, such as temperature, mosquito density and immunity in the amplification hosts (birds). © fri/aerzteblatt.de