Disease-transmitting mosquitoes spread
Global trade in goods and travel and climate change have helped mosquitoes that transmit dangerous infectious diseases to spread widely. The tiger and yellow fever mosquitoes in particular have already established themselves in southern Europe and are expanding further north. German researchers took a closer look at the spread of these dangerous mosquitoes. A spread of these species is also likely in Germany in the near future.
Scientists from Goethe University and the Senckenberg Society for Natural Research recently compared the ecological niches of tiger and yellow fever mosquitoes on different continents. The researchers' result: Over the next ten to 50 years, infections transmitted by these insects will increase. These insects were originally native to tropical and subtropical areas. With the increasing spread of these species, the risk area for the tropical diseases they transmit is expanding. The research results were recently published in the journal "Nature Scientific Reports".
Infectious diseases will increase
"In the next one to five decades, vector-borne infectious diseases will increase," reports the study team led by Prof. Dr. Sven Klimpel in a press release on the study results. Vectors are disease transmitters that can transmit causative agents to another host without becoming ill themselves. The tiger and yellow fever mosquitoes belong to the vectors. If such species find pathogens in their new distribution areas, they also contribute to their spread and widen the risk area of these diseases.
About the yellow fever mosquito (Aedes aegypti)
"Due to its long 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 carrier of yellow fever, dengue fever and Zika viruses as well as some other viral diseases. The spread of this mosquito originating from Africa started 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 been spreading 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 tires over the sea
The tiger mosquito is one of the 100 worst invasive species. It originally comes from South and Southeast Asia. Long-distance travel and the transport of goods contributed to the massive spread. Eggs, larvae and pupae of the tiger mosquito find good survival conditions, especially in the water that has been collected in old car tires or in which bamboo plants are traded.
New ecological niches
The scientists examined the ecological niches of both species in which the insects can occur. According to the researchers, both species have a broad niche and can occur under a variety of different environmental conditions. The scientists found the biggest difference in the dissemination 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 occur wherever it would find good living conditions.
Great spreading potential for the tiger mosquito
From this, the researchers will derive a strong spread for this species in the near future. "In the meantime, the Asian tiger mosquito is almost widespread in southern Europe," says Klimpel. Due to the wide niche that this insect occupies, the specialist considers it unstoppable to spread to Northern Europe. According to the expert, other exotic mosquitoes such as Aedes japoniucs (Asian bush mosquito), Aedes koreicus or Aedes atropalpus will follow, or have already established themselves in Central Europe. (vb)