Zika Virus: New Findings
All content is checked by medical journalists.The Zika virus continues to spread rapidly in tropical countries. It has now been proven that the pathogen can also be transmitted during sex. And the suspicion that the mostly harmless disease can be dangerous not only to the unborn but also to adults in individual cases seems to be confirmed. An overview of the current state of knowledge about Zika.
How is the disease transmitted?
Through mosquitoes: In the vast majority of cases, Zika is transmitted through the bite of mosquitoes, especially the Egyptian tiger mosquito, and probably also by the related Asian tiger mosquito.
From mother to child: If pregnant women are infected, the virus can be transmitted to the child.
During sex: Zika viruses were found in the semen of sick men some time ago. The suspicion of sexual transmission has now been confirmed. One such case recently became known in France. There a woman was infected from her partner who had returned from a trip to Brazil. However, the probability of transmission during sex is many times lower than with a bite from infected mosquitoes.
Other routes of transmission: It is not yet known whether Zika viruses can also be transmitted through blood, urine and saliva, and if so, how high the risk of infection is in this way.
How dangerous is the disease really?
For unborn babies: The infection can be the most dangerous for unborn babies. It is now considered highly likely that Zika virus infection in the mother can cause severe brain damage in the unborn child.
In Brazil, for example, where Zika fever has been increasing since 2015, a certain malformation of the skull in newborns has suddenly increased - so-called microcephaly. There are now 500 confirmed and hundreds of suspected cases. In this developmental disorder, the child's head is too small. Brain damage and disabilities are the result. Even if final proof of the connection is still pending, experts (including the German Foreign Office) warn pregnant women against traveling to Zika regions.
For healthy adults: An infection in adults is usually mild and only one in five infected people experience symptoms of the disease. Typical signs of an infection are a slight fever, lumpy skin rashes, joint pain, and sometimes reddened eyes as a result of conjunctivitis. However, some patients feel very ill and also suffer from headache and muscle pain, some also from dizziness, stomach pain, nausea with vomiting and diarrhea. Such severe disease courses, as is otherwise known from the related dengue or yellow fever, are very rare.
Exceptional complication Guillain-Barré Syndrome (GBS): In isolated cases, the virus can apparently cause severe nerve damage in the long term: After the outbreak on the islands of French Polynesia, the incidence of the otherwise rare Guillain-Barré Syndrome (GBS) increased twenty-fold. According to the latest projections, 24 out of 100,000 Zika infected people are believed to develop GBS. In this disease, the immune system attacks the protective covering of the nerve fibers. Then significant paralysis and sensitivity disorders occur, especially of the limbs. The nerve damage can also affect the heart and breathing, putting life in danger.
Why is the disease spreading so quickly?
Initially, the infection occurred mainly in Africa, Southeast Asia and the Pacific islands. Since the beginning of 2015, the disease has spread rapidly from Brazil across the South American continent and has now also reached North America. The main reason for the rapid spread is that the infection is new in South America and therefore there is no immunity in the population. Since the mosquitoes that transmit the disease are found all over North, Central and South America, with the exception of Chile and Canada, the World Health Organization expects Zika to conquer all of America. Experts expect four million infected people on the American continent in the near future.
Can the disease also come to Germany?
Zika viruses are usually transmitted by the Egyptian tiger mosquito. Whether mosquitoes native to Germany could also act as a vector is questionable and is currently being researched. However, specimens of the Asian tiger mosquito that has a higher potential to transmit Zika can already be found in this country. In order to be infected by a bite, the animal must first have sucked blood from an infected person. Since there is no virus reservoir in Germany, the risk of becoming infected in this way is, at least currently, almost zero.
So far, the isolated cases registered in Germany had all been infected while traveling to Zika areas. However, infected travelers can infect their sexual partners. Therefore, experts recommend practicing safe sex to protect your partner for at least four weeks after a trip to Zika areas.
How can you protect yourself?
So far there is no effective drug against Zika - you can only treat the symptoms of the disease. There is also no corresponding vaccination yet. The best protection for travelers is therefore not to get stung in the first place. You should also note the following:
- Do not travel to risk areas if you are pregnant.
- After traveling to affected areas, practice safe sex for at least four weeks. This also applies if you do not feel sick.
- Wear light colored clothing with long sleeves and pants when in Zika areas.
- Apply repellants (anti-mosquito repellants) to uncovered areas of skin several times a day.
- Use impregnated mosquito nets over the bed and on the windows.
- Avoid and eliminate watering holes where the mosquitoes multiply.
- If symptoms of illness such as fever, red eyes, skin rash, nausea, headache and body aches occur after traveling to risk areas, you should consult a doctor.
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Sources:
Press release German Center for Infection Research, March 2nd, 2016
WHO, www.who.int, accessed on 02.03.2016
Robert Koch Institute, Answers to Frequently Asked Questions (FAQ): Zika virus infections, as of February 25, 2016
