14. April 2022 – 16:30 watch
by Ingo Jacobs
Scientists warn the world could be on the verge of a new Zika virus outbreak. The virus made headlines around the world in 2016. Thousands of babies have been born with brain damage after their mothers became infected during pregnancy. According to US researchers, a single mutation is enough to trigger an explosive spread. The BBC reports. Are invasive mosquito species a threat to us in times of climate change?
Zika infection in pregnancy leads to microcephaly
If a mother contracts the Zika virus during pregnancy, it can damage the baby’s development and result in microcephaly, with damaged brain tissue. Zika is transmitted through bites from infected Aedes aegypti mosquitoes.
A laboratory study from the La Jolla Institute for Immunology in California, which has now been published in the journal Cell Reports, says: The Zika virus can change very easily and quickly create new variants. They would then be much more successful in the transfer. And this even in countries that have built up immunity after previous Zika outbreaks, according to the research team.
Reading Tip: First Zika virus transmission of 2019 in Europe
Skull malformations in a baby from Zika infection during pregnancy.
Laboratory testing only shows the obvious
“Ultimately, however, the researchers here in the laboratory have only proven that the Zika virus can also mutate quickly,” says medical expert Dr. Christopher Specht. “But that’s not surprising, that applies to almost every virus.” There would therefore be no cause for acute concern for the individual in Europe and Germany – because the spreading mosquito species Aedes aegypti is primarily at home in Asia and on the American continent.
In addition, only 20 percent of all those affected are symptomatic after an infection and a Zika disease course is rather harmless, according to the expert. In this country, only people who want to travel to the affected regions of the world and plan to have offspring have to worry.
Health authorities monitor invasive mosquito species
Nevertheless, German health authorities such as the Robert Koch Institute also monitor very closely which mosquitoes and thus viruses and parasites are spreading in Europe and Germany. Because since 2015 there have been increasing observations that certain species are increasingly settling here.
“In principle, the famous old tire filled with water on a ship is enough to provide the mosquitoes with a breeding ground,” says Specht, who enjoyed part of his training at the Liverpool School of Tropical Medicine. In this way, previously non-native species are brought to Europe.
Reading Tip: Our mosquitoes are becoming more and more dangerous – serious illnesses after mosquito bites are possible
IN VIDEO: Mosquito sterilization to save lives (archive, 2019)
Malaria was not defeated in Europe until the late 1960s
For example, after decades of absence, the Aedes aegypti mosquito reappeared in 2020 on the Black Sea coast of southern Russia, Georgia and also in Turkey. In addition, the species was responsible for a dengue fever epidemic in 2012-2013 with around 2,000 registered cases in Madeira, and in 2017 it was detected in Fuerteventura.
And indeed, it is not that long ago that malaria, for example, was an issue in Europe, especially in Italy – albeit, thank God, the more harmless variant Plasmodium vivax. Only at the end of the 1960s was it possible to eradicate mosquitoes and thus the disease-causing parasites in Europe.
cycle between humans, animals and insects
In order for mosquitoes to be able to transmit the diseases at all, the climatic conditions here have to change. Because the development cycle of the mosquitoes – and thus the viruses and parasites – runs faster at high temperatures and good food availability. “This is the classic case in the Rhine Graben,” says Specht.
Viruses, bacteria and parasites can also develop there under appropriate climatic conditions. Before diseases such as dengue, Zika, West Nile fever and malaria can actually spread again, a stable cycle of infections in humans, animals and insects is also required.
Reading Tip: WHO warns – Malaria could spread again in Europe
Climate change is becoming a problem for us too
“It’s a coming problem,” the prevention doctor tells us, “you definitely have to keep that on your radar.” At the moment, however, it does not look like an acute threat – but it will come if climate change continues to develop. “Surveillance, that is, monitoring by the authorities, is needed in order to first recognize: ‘Where is what?'” says Specht, “but that is not very easy.”
In further steps, attempts will then be made, for example in the case of the Rhine ditches, to decimate the mosquito populations by means of biological pesticides or sterilization of the males.