Trapped mosquitoes spread a new disease

The tiger mosquito also transmits the tropical Chikungunya virus in this country

What has been recently suggested repeatedly is scientifically proven for the first time: trapped tiger mosquitoes can transmit diseases in Germany. Researchers have shown that the tiger mosquito in this country is capable of spreading the tropical Chikungunya virus at lower temperatures. Such a viral infection can cause severe, debilitating and often chronic joint pain.

In the high-security insectarium of the Bernhard Nocht Institute of Tropical Medicine (BNITM), a research team has experimentally demonstrated that the Asian tiger mosquito is relatively mild in Germany. Temperatures around 18 degrees Celsius can spread tropical Chikungunya viruses. Thus, a spread of viruses is also likely in German regions if the tiger mosquito population continues to increase. The results of the research were recently published in the journal "Eurosurveillance"

Chikungunya virus can spread in Germany

Unlike many other tropical viruses, Chikungunya virus is also active at temperate temperatures that are common here. In other European countries, such as Italy and France, outbreaks have already been confirmed by the authorities in 2017. BNITM researchers have shown that such outbreaks are also possible in Germany

Moderate temperatures of 18 degrees C are sufficient

In the laboratory, BNITM researchers used Aedes albopictus viral mosquitoes from Germany and Italy for two weeks in climatic chambers. with average temperatures of 18, 21 or 24 degrees. "In the mosquitoes of the German population, the virus has been able to multiply very well even at a temperature of 18 degrees," reports Professor Egbert Tannich, director of the National Reference Center for Tropical Infectious Diseases at BNITM in a press release . After two weeks, more than 50% of the animals had infectious viruses in their saliva, says the expert.

The population is decisive

According to Tannich, it is therefore proved that the Chikungunya virus is less affected by the outside temperature but mainly determined by the appearance of the carrier mosquito. "Currently, the risk of transmission of Chikungunya virus to humans in Germany is considered low," says the professor. The tiger mosquito is currently locally limited and to be found in small numbers in Germany. The tiger mosquito is already native to 25 European countries

The two mosquitoes Aedes aegypti and Aedes albopictus, known as tiger mosquitoes, are considered the most important vectors of Chikungunya viruses. In Germany and Germany, for example, Aedes albopictus is native to Italy and along the Upper Rhine Plain in Germany and France. According to the Bernhard Nocht Institute, this mosquito species has already been established in more than 25 European countries

Caution is advised

Tannich and his colleagues strongly recommend a corresponding system for control and mosquito control in all European countries with established populations of Aedes albopictus. Insect experts conclude that tiger mosquito expansion can be prevented by reduction or elimination.

According to BNITM researchers, the presence of viruses in a mosquito alone is not enough for transmission. out. Two events must occur here: First, a tiger mosquito in Germany must bite a person who has tropical viruses in his blood. Secondly, the mosquito should be able to multiply and transmit the virus. For most tropical viruses, this is usually only possible at outside temperatures above 25 degrees Celsius over a period of several weeks.

Preliminary Relief for Zika, Dengue and West Nile Viruses

For Other Tropical Pathogens Like Zika, Dengue or even West Nile virus, which causes serious tropical diseases, BNITM experts are currently seeing a low risk of spread, because these viruses only multiply at very hot temperatures that last several weeks. "These conditions of an average of 25 to 27 degrees are usually not found here in Germany," Tannich concludes.

Double Control

The professor sees Zika, Dengue and West Nile viruses as a double natural control. On the one hand, these tropical viruses would be inhibited by the prevailing temperatures and, on the other hand, the appearance of carriers would be very small. (Vb)