The Zika virus is transmitted by mosquitoes. 60 to 80 percent of infected people show no symptoms, but if infected during pregnancy, there is a risk of skull malformation in fetuses and newborns.

There are two lineages of the Zika virus, the African lineage and the Asian lineage (Pacific region and in South and North America). In 2013 and 2014, there were several outbreaks in the Pacific region. In 2015, the Zika virus spread to South America. In principle, transmission within Europe is also possible.

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Zika virus is transmitted by the yellow fever mosquito or by the Asian tiger mosquito. The virus can also be transmitted from mother to child during birth (perinatal) and during sexual intercourse (sexual). Zika has been detected in semen, vaginal fluid, saliva, urine, and breast milk.

60 to 80 percent of infected people show no symptoms. An illness usually manifests itself in mild fever, headache, muscle and joint pain, skin rashes. These symptoms are usually not very pronounced and last two to seven days. However, infection during pregnancy carries the risk of congenital Zika syndrome (malformation of the skull in fetuses and newborns) and other complications such as premature birth or miscarriage.

There is no specific therapy for Zika virus disease

There is no vaccine. When travelling to countries where the Zika virus is present, make sure you have adequate mosquito repellent.

Since 2011, mosquitoes have been monitored for pathogenic viruses such as West Nile virus, dengue, chikungunya and also Zika virus via the AGES mosquito monitoring system.

Zika virus from the genus Flavivirus was first isolated in Africa in 1947 (Zika forest, Uganda). There are two lineages, the African lineage and the Asian lineage (Pacific region and in South and North America). Zika virus is transmitted by mosquitoes of the genus Aedes (yellow fever mosquito Aedes aegypti, Asian tiger mosquito Aedes albopictus). The virus can also be transmitted from mother to child during birth (perinatal) and during sexual intercourse (sexual) (WHO). Zika has been detected in semen, vaginal fluid, saliva, urine, and breast milk(CDC). In 2013 and 2014, there were several outbreaks in the Pacific region. In 2015, Zika virus spread to South America.

Disease pattern

The incubation period is three to 12 days. The majority of infected people (60 to 80 percent) show no symptoms. An illness usually manifests itself in mild fever, headache, muscle and joint pain, skin rashes. These symptoms are usually mild and last two to seven days. There is no vaccine.

Disease outbreaks in French Polynesia and Brazil showed an increase in microcephaly in fetuses and newborns. In microcephaly (literally "small head"), the circumference of the head is significantly smaller than a healthy person of the same age and sex. Microcephaly is associated with mental retardation.

Risk

Since the peak of the Zika epidemic in the Americas in 2016, most countries in the Americas and the Caribbean have seen a decline in cases. In Asia, surveys and epidemiologic surveillance suggest widespread geographic distribution of Zika virus, while information on spread in Africa is still limited. In areas where transmission has been successfully interrupted, the likelihood of large outbreaks is currently low due to herd immunity in the population. Thus, the likelihood of travelers is contact with Zika virus in such settings is also low.

Pregnant women and their partners, as well as couples planning to become pregnant, should be fully informed about the risk of Zika virus infection. Pregnant women are still advised against traveling to affected countries. If they do travel to affected countries, they should discuss the situation with their health care provider before traveling.

Because of this risk, certain rules of conduct should still be followed when planning to travel to endemic areas:

• Avoid insect bites, use insect repellent according to the instructions for use.
• Wearing long-sleeved shirts and long pants. The mosquitoes that transmit the Zika virus are mainly diurnal, so they also bite between sunrise and sunset.
• Sleeping or resting should be done, even during the day, in screened or air-conditioned rooms or under a mosquito net
• Use of condoms. To prevent possible infection of the fetus, consistent use of condoms or abstinence is recommended for the entire duration of an ongoing pregnancy.

In principle, transmission within Europe is also possible, as mosquitoes such as the Asian tiger mosquito, a likely vector, have also become native to Europe (Mediterranean region). In August 2019, the first European-wide transmissions of Zika virus by Asian tiger mosquitoes living here were documented in France. More information European Centre for Disease Prevention and Control (ECDC): Updated rapid risk assessment on Zika virus in the Americas and potential complications Centers for Disease Control and Prevention (CDC): Zika virus World Health Organization (WHO).