Zika virus: new findings

The Zika virus continues to spread rapidly in tropical countries. Now it has been proven that the pathogen can also be transmitted during sex. And the suspicion that the mostly harmless disease can be dangerous not only unborn, but also adults in individual cases seems to be confirmed.

Zika virus: new findings

The Zika virus continues to spread rapidly in tropical countries. Now it has been proven that the pathogen can also be transmitted during sex. And the suspicion that the mostly harmless disease can be dangerous not only unborn, but also adults in individual cases seems to be confirmed. An overview of the current state of knowledge on Zika.

How is the disease transmitted?

By mosquitoes: In the vast majority of cases Zika is transmitted by the bite of mosquitoes, especially the Egyptian tiger mosquito, and probably also by the related Asian tiger mosquito.

From mother to child: In infected pregnant women, the virus can be transmitted to the child.

During sex: Zika viruses have been detected in sperm of ill men some time ago. In the meantime the suspicion of a sexual transferability has been confirmed. One such case has recently become known in France. There, a woman had been infected by her partner, who had returned from a trip to Brazil. However, the likelihood of transmission during sex is much lower than in the case of a sting caused by infected mosquitoes.

Other transmission paths: Whether Zika viruses can be transmitted by blood, urine and saliva, and if so, how high the risk of infection in this way, is not yet known.

How dangerous is the disease really?

For unborn children: Most dangerous, the infection may well be unborn. It is now considered highly likely that a mother's Zika virus infection can cause serious brain damage to the unborn child.

For example, in Brazil, where Zika fever has been on the increase since 2015, a certain malformation of the skull in newborns has suddenly increased - the so-called microcephaly. There are now 500 confirmed and hundreds suspected cases. In this developmental disorder, the child's head is too small. Brain damage and disability are the result. Even if definitive proof of the connection is still pending, experts (including the German Foreign Office) warn pregnant women from traveling in Zika regions.

For healthy adults: In most cases, infection in adults is mild, with only one in five infected with symptoms of disease. Typical signs of an infection are mild fever, gnarled skin rashes, joint pain, sometimes red eyes due to conjunctivitis. However, some patients feel very ill and also suffer from headaches and muscle aches, some with dizziness, stomach aches, nausea with vomiting and diarrhea. Such severe illnesses, as they are otherwise known from the related dengue or yellow fever, but are very rare.

Exceptional complication Guillain-Barrรฉ syndrome (GBS): Sporadically, the virus may cause severe nerve damage in the long term: For example, after the outbreak in the French Polynesian islands, the incidence of the otherwise rare Guillain-Barrรฉ syndrome (GBS) increased twentyfold. Of the 100,000 Zika infected people, the latest projections suggest that 24 are suspected of having GBS. In this disease, the immune system attacks the protective sheaths of the nerve fibers. Then there are significant paralysis and sensory disturbances, especially of the limbs. The nerve damage can also affect the heart and breathing, so there is a danger to life.

Why is the illness spreading so fast?

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 to the South American continent and has since reached North America. The reason for the rapid spread is above all that the infection is new in South America and thus there is no immunity in the population. As the mosquitoes that transmit the disease, with the exception of Chile and Canada, are found throughout North, Central and South America, the World Health Organization (WHO) assumes that Zika will conquer all of America. Experts expect four million infected people in the Americas for the near future.

Can the disease also come to Germany?

Zika viruses are usually transmitted by the Egyptian tiger mosquito. Whether even domestic mosquitoes could act as transmitters in Germany, is questionable and is still being researched. However, you can already find specimens of the Asian tiger mosquito in this country, which has a higher potential to transfer Zika. In order to be infected by a sting, the animal must have previously sucked blood from an infected person. Since the virus reservoir is missing in Germany, the risk of becoming infected in this way, at least currently still approaches zero.

So far, the isolated in Germany registered patients had all infected on trips to Zika areas. However, infected travelers can infect their sexual partners. Therefore, experts recommend practicing safe sex at least four weeks after traveling to Zika areas to protect their partner.

How can you protect yourself?

There is no effective drug against Zika - you can only treat the symptoms of the disease. Also a corresponding vaccination does not exist yet. The best protection for travelers is therefore not to be stung. You should also note the following:

  • Do not travel in 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 bright, long-sleeved clothing and pants when staying in Zika areas.
  • Apply Repellentien (anti-mosquito) several times daily on uncovered skin surfaces.
  • Use impregnated mosquito nets over the bed and windows.
  • Avoid and eliminate waterholes where mosquitoes multiply.
  • If symptoms of illness such as fever, red eyes, rash, nausea, headache and body aches occur after traveling to high-risk areas, you should consult a doctor.

(Cf)

Sources:

Press release German Center for Infection Research, 02.03.2016

WHO, who.int, call 02.03.2016

Robert Koch Institute, answers to frequently asked questions (FAQ): Zikavirus infections, as of 25.02.2016


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