The Zika virus (ZIKV) is a virus first detected in East Africa that is transmitted by mosquitoes. While Zika infection is mostly safe for healthy adults and usually causes no or only mild symptoms, infection during pregnancy can cause serious damage to the fetus.
Transmission by mosquitoes
The virus is mainly transmitted by the yellow fever mosquito, also known as the Egyptian tiger mosquito (Aedes aegypti), which is found in all tropical and some subtropical countries. In addition, it is suspected that other mosquito species of the genus Aedes, such as the Asian tiger mosquito, can infect humans with the virus.
Occasionally, cases of sexual transmission of the Zika virus or infection during childbirth (from mother to child) have been described. Also due to blood transfusions, it came to the disease. Whether an infection by urine or saliva is possible, is not yet known.
Symptoms of Zika infection
Infection with Zika virus causes symptoms similar to those of other mosquito-borne diseases such as dengue fever. In comparison, however, Zika infections are significantly milder. Signs include:
- Fever (hence the name "Zika Fever")
- nodular-blotchy rash
- joint pain
- Conjunctivitis (conjunctivitis)
- less common: muscle and headache as well as vomiting
The incubation period, ie the time from the infection with the virus to the onset of symptoms, is usually three to twelve days. The complaints usually last a few days to a week.
It is estimated that about four out of five people have no symptoms at all. Usually the infection heals without further consequences.
Treatment of Zika infection
Since there is currently no specific treatment for the Zika virus, only a treatment of the symptoms. As a rule, analgesics and antipyretic drugs are administered. In addition, rest and drinking sufficient amounts of fluid are recommended.
Trigger of sequelae?
The Zika virus is usually safe for a healthy adult. However, it is likely that the virus can trigger Guillain-Barré syndrome, a nerve disorder that causes paralysis.
In addition, speculation about a connection with the emergence of other secondary diseases, such as spinal cord or meningitis, which were observed in individual cases after a Zika infection.
Zika infection in pregnancy
It has been proven that Zika infection in the first trimester of pregnancy in the unborn baby can trigger microcephaly, a malformation of the brain.
In the risk areas, an increasing number of microcephaly cases in newborns could be observed. However, it is still unclear how often infecting the virus with babies actually results in microcephaly.
The sick children are born with a much smaller head and a mostly underdeveloped brain.
Protection against infection
So far there is no vaccine against the Zika virus. As a precautionary measure, avoiding the risky regions and general methods for repelling mosquitoes is recommended, if possible, especially for pregnant women.
Since sexual transmission is probably also possible, the use of condoms is also recommended.
Anyone who has survived a Zika infection is then considered immune to re-infection with the virus.
Origin and distribution of the Zika virus
The virus was first isolated in 1947 in a rhesus monkey in Zika Forest in Uganda and thus got his name. There are two lines of the Zika virus: the African and the Asian. The virus belongs to the genus Flavivirus, which is assigned to various viruses that are transmitted by ticks or mosquitoes. These include the viruses that cause yellow fever, TBE and dengue fever.
In humans, the Zika virus was first detected in Uganda and Tanzania in 1952. By 2007, people were infected only in Africa and Southeast Asia. Since the beginning of 2015, the virus has been frequently observed in Central and South America, especially in Brazil and Colombia.
Through travelers, the Zika virus has also spread to other areas, causing cases of Zika fever in many countries among travelers. However, no cases of transmission in Germany are known.