Risk of Zika transmission by mosquitos in Germany analysed
Under certain conditions, Asian tiger mosquitoes that have been imported into South Germany are able to transmit the Zika virus
In laboratory experiments, scientists at the Bernhard Nocht Institute for Tropical Medicine (BNITM) and the DZIF have confirmed that some specimens of the Asian tiger mosquito Aedes albopictus that had been imported into southern Germany are able to transmit the Zika virus at temperatures of at least 27°C. In contrast, the widespread common mosquito Culex pipiens and related species such as Culex torrentium seem to be unable to transmit the virus. The work has recently been published in the journal Eurosurveillance.
“The risk of a Zika transmission is estimated to be very low because the tiger mosquito has only been found sporadically in Germany to date,” says Prof Egbert Tannich from the BNITM. Additionally, the existence of the mosquitoes alone does not suffice for a transmission. “To start, the tiger mosquito has to bite a person who has the Zika virus in his/her blood—which is rather rare. And secondly, very warm temperatures of at least 27°C need to exist over a period of 10 to 20 days so that the mosquito can replicate and transmit the virus,” adds Prof Norbert Becker from the “Gesellschaft zur Förderung der Stechmückenbekämpfung (GFS)” in Speyer, which participated in the study.
For the transmission analysis, the mosquitoes were experimentally infected by being fed on blood containing the virus in a special safety laboratory. After two to three weeks, a small drop of mosquito saliva was collected and investigated for virus particles.
The Zika virus is a member of the Flaviviridae family and was originally isolated in Uganda in 1947. It is transmitted by mosquitoes, especially the yellow fever mosquito Aedes aegypti and, in rare cases, causes fever with joint pain. Most infected people have no symptoms at all and the virus disappears from the body after a few days. However, infection during pregnancy can cause severe damage to the unborn child. To date, a vaccine or effective treatment has not yet been available.
