Tropical diseases like yellow fever, dengue and Zika soon also in Germany?

Disease-transmitting mosquitoes are spreading

Global trade and travel and climate change have contributed to the spread of mosquitoes that transmit dangerous infectious diseases. In particular, the tiger and the yellow fever mosquito have already established themselves in southern Europe and continue to expand to the north. German researchers have taken a closer look at the distribution of these dangerous mosquitoes in a study. A distribution of these species is also likely in Germany in the near future.

Scientists from the Goethe University and the Senckenberg Gesellschaft für Naturforschung have recently compared the ecological niches of tiger and yellow fever mosquitoes on different continents. The result of the researchers: Over the next ten to 50 years, infections transmitted by these insects will increase. Originally, these insects were native to tropical and subtropical areas. As these species spread, so too does the risk area for the tropical diseases they transmit. The research results were recently published in the journal "Nature Scientific Reports".

A German study project predicts the spread of disease-carrying mosquitoes in Northern Europe in the near future. (Image: Flavio_Brazil / fotolia.com)

Infectious diseases will increase

"In the next one to five decades, vector-borne infectious diseases will increase," reports the study team headed by Prof. Dr. med. Sven Klimpel in a press release on the study results. Vectors are disease carriers that can transmit causative agents to another host without suffering from self-infection. The tiger and yellow fever mosquito belong to the vectors. When such species find pathogens in their new distribution areas, they also contribute to their spread and extend the risk area of ​​these diseases.

About the yellow fever mosquito (Aedes aegypti)

"Due to its longer immigration history of 300 to 400 years, the yellow fever mosquito fills its niche in non-native areas almost completely," explains Klimpel. The yellow fever mosquito is considered the main transmitter of yellow fever, dengue fever and Zika virus as well as some other viral diseases. The spread of this African-born mosquito began several hundred years ago. The scientists suspect that the widespread sugar cane plantations and the slave trade favored this spread.

About the tiger mosquito (Aedes albopictus)

In contrast to the yellow fever mosquito, the immigration history of the tiger mosquito is still relatively young. According to the researchers, this has only spread more and more for 30 to 40 years and has not yet reached all places where it would find suitable environmental conditions, according to Klimpel. The tiger mosquito can also transmit the Zika virus and the dengue virus, but also other pathogens such as the West Nile or the Chikungunya virus.

In bamboo and old car tire over the sea

The tiger mosquito is one of the 100 worst invasive species. She is originally from South and Southeast Asia. Long-distance travel and the transport of goods contributed to the massive spread. In particular, in the water that has collected in old car tires or traded in the bamboo plants, eggs, larvae and pupae of the tiger mosquito find good survival conditions.

New ecological niches

The scientists studied the ecological niches of both species in which the insects can occur. Both species, according to the researchers, have a broad niche and can occur under a variety of environmental conditions. The biggest difference was found by the scientists during the distribution period. While the yellow fever mosquito has already occupied all possible niches in its new distribution areas due to its longer immigration history, the tiger mosquito does not yet appear everywhere, where it would find good living conditions.

Great propagation potential for the tiger mosquito

From this, the researchers deduce a strong spread for this species in the near future. "Meanwhile, the Asian tiger mosquito is widespread in southern Europe," says Klimpel. Because of the broad niche that this insect occupies, the skilled artisan sees a spread to northern Europe as unstoppable. Other exotics among the mosquitoes such as Aedes japoniucs (Asian bush mosquito), Aedes koreicus or Aedes atropalpus will follow in the view of the experts, or have already established themselves in central Europe. (Vb)