Tiger mosquitoes bring fever virus to Europe

Chikungunya: mosquitoes bring virus to Europe

02/26/2014

Experts are currently warning that several Chikungunya infections have been registered in the Caribbean. The Chikungunya fever is transmitted by various mosquitoes such as the tiger mosquito. This insect, originally from Asia, has spread to other parts of the world in recent decades. They were also spotted in southern Germany.

Pathogen has made it to the Americas
Several Chikungunya infections have been reported in the Caribbean since December of last year. The Düsseldorf Center for Travel Medicine (CRM) warns against that. The French part of St. Martin, where almost 400 cases were reported by the end of January, was particularly affected. Further cases were reported from Martinique, Guadeloupe, the Virgin Islands, Dominica and Saint-Barthélemy. The pathogen, originally native to Asia and Africa, has demonstrably made the leap to the American continent for the first time. Tomas Jelinek, the scientific director of CRM, expects a further geographical spread of the virus. Especially in Central and South America, but also in Europe it is „already come to transmissions.“

Diseased people could hardly keep upright because of the pain
The Chikungunya fever is transmitted, among other things of the tiny, only about five millimeters large Asian tiger mosquito (Aedes albopictus). „Chikungunya fever is a feverish disease characterized by severe muscle and joint pain“, said Susanne Glasmacher, biologist and spokeswoman for the Robert Koch Institute in Berlin. „After an incubation period of three to seven days, a fast-rising high fever occurs.“ The patient is often unable to sustain himself because of the severe pain in his muscles and joints. This fact has also given the disease its name, because Chikungunya in the language of a Bantu people means something like: „The bowed one“. Lymphadenopathy, redness, headache, mucosal bleeding in the nose or mouth, as well as stomach and intestinal complaints can also occur in the case of an illness.

Americans and Europeans lack protection
The virus was first discovered in East Africa in the 1950s and spread to West Africa, India, and Southeast Asia, where it did not pose any particular problems, as the local population apparently had encountered it early in its evolution and become immune to it. However, this protection is lacking to Americans and Europeans. Scientists at the Institut Pasteur have discovered that the pathogen, which was originally transmitted mainly by the yellow fever mosquito, had a serious mutation around 2005. Accordingly, the pathogen can since then optimally multiply in the diurnal Asian tiger mosquito.

Tiger mosquitoes found in southern Germany
As a result of climate change and global trade routes, the tiger mosquito has long spread far away from the original area of ​​origin. In 2007, for example, eggs were first discovered by her in Baden-Württemberg, and four years later live females went into the net, preferably at motorway rest stops. Even in Bavaria already living specimens have been caught. In addition, the mosquitoes are also located in other European regions and in 2007, there was an outbreak of fever in the Italian province of Ravenna with more than 200 registered cases.

There is still no vaccine against Chikungunya fever
There is still no effective vaccine protection against Chikungunya fever. „It will probably take a few years before there will be an approved vaccine, because such a vaccine must fulfill many requirements“, said Susan Knoll from the Association of Research-Based Pharmaceutical Companies (vfa) in Berlin. The vaccine must ideally be able to combat the three previously known variants of the virus. And since the fever so far occurs mainly in developing countries, he must also be low in production. „Research on a vaccine is not only time-consuming, but development must pay off for industry as well“, said Jonas Schmidt-Chanasit, working group leader for arboviruses at the Bernhard Nocht Institute in Hamburg.

After survival of the disease lifelong immune
A doctor, who already had to do with the disease, is the Munich tropical medicine Nikolaus Frühwein. He has already dealt with several cases that had been introduced by travelers. „Chikungunya is not as dangerous as dengue fever, but extremely uncomfortable because it is so painful“, so early wine. The disease can currently only be treated symptomatically by the administration of analgesic and antipyretic drugs. Although there is also a hemorrhagic form of fever, which can lead to life-threatening bleeding in the infected, but this risk is low. „However, deaths at Chikungunya have so far been very rare“, said Jonas Schmidt-Chanasit from the Bernhard Nocht Institute. In most patients, the disease resolves after one to two weeks and no damage is left. However, around five to ten percent of the infected people suffer from months of illness, and in rare cases even years, joint pain as a result of the disease. On the positive side, however, those who once become infected with Chikungunya fever and have survived the disease are immune to it for a lifetime.

Protection against mosquito bites
Experts like the CRM recommend travelers who are in the main distribution areas of the mosquito to protect themselves from stings. This is especially true in the affected regions in the Caribbean, but also in Central Africa or in Southeast Asia. To protect against the mosquitoes carrying mosquitoes, mosquito-repellent sprays and lotions help, which should not only be applied to the skin and clothing in the evening. The funds should contain a high proportion of the active substance DEET, as this distributes the annoying insects. In addition, mosquito nets can keep out the annoying mosquitoes. In addition, it is advisable to wear light clothing that is better than dark or porous. (Sb)

Image: Kerstin 197016351a2cc0b08c03>