As the Zika Virus 2015 raged in Brazil, images of babies around the world born with a deformed, small head. The pathogen spread rapidly, until the end of 2016, 48 countries in Latin America and the Caribbean were affected. The world health organization (WHO) called for in February of 2016, the global health emergency.
Enormous efforts have been made to curb the epidemic: men in yellow safety suits sprayed insecticide fog, Pregnant women should not travel to the affected areas. The magazine “Scientific American” said about: “Is Zika the end of humanity?”
Suddenly, to the global risk mutated
In the process, Zika was not Unknown. The Virus had spread before 2015, however, it seemed mostly harmless. The Infected suffered, if any, under mild fever, joint pains and headaches. The skin rashes were mild and nonspecific symptoms, which resolved most quickly.
That Zika mutated to the global risk came as a surprise. “Who would have warned five years ago before the Virus, would have been a laugh,” says the medical doctor and virologist Jan Felix Drexler of the Charité.
Today, more than three years after the WHO warning, it became quiet around Zika.
- Have been exaggerated the reactions at the time?
- How is the situation now in Brazil?
- And as it goes to the affected families and children?
“The great outbreak ended, but that does not mean that the Virus has disappeared from Latin America,” says the physician, Philip Eisermann from the Bernhard-Nocht-Institute for tropical medicine (medical establishment has treated you) in Hamburg. “As people get there, but will be significantly less.”
Example, Brazil: During the Outbreak of the epidemic in 2015, were reported in the country of 56,000 fell Ill with typical symptoms, in 2016 there were 274.000. In the following year, in 2017, the number dropped to around 32,000, 2018 19.020. A decline was also evident in other countries – such as in Colombia or Venezuela.
The experts from the medical establishment has treated you to confirm this course. “We are testing travellers, but have no Zika cases,” says Eisermann. In 2016, there were several Hundred, 2018 is only four.
The yellow fever mosquito (Aedes aegypti): This Moskitoart transmitting the Zika Virus
“Often Zika goes unnoticed”
Since infection is often without symptoms, the doctors however, a large number of unreported cases. “The Figures are likely to be during the epidemic, significantly higher than specified,” says Eisermann. “Zika often remains unnoticed.”
The disease wave flattening in Latin America, is probably mainly due to the fact that many people have made the infection by. In their blood of antibodies against the Virus are formed, against a new infection, you are immune. Sufficient people are prepared for so, it prevents this so-called herd immunity, the Virus spread quickly. The chain of Transmission is interrupted, the fire suffocated.
“How long will the immunity in the Individual stops, however, is unclear,” says virologist Drexler, one of the researchers of the Virus, and several times in Brazil before the place was. At best, the hope of a lifetime. Then it would behave Zika similar to the closely related yellow fever Virus. Drexler is not to be feared, however, that it is quite as simple as that: “in Brazil Alone, there are twelve different flaviviruses, including Zika. We know little about their Interaction, and whether an infection with another Virus – such as yellow fever – Zika-strengthens the immune system, or weaken.”
Why it came to the outbreak in Brazil?
It is known that the Virus from Asia migrated across the Pacific to South America, so Eisermann. There, it met a completely unprotected population – the ideal conditions to spread. Also suitable to the climate, and the vectors are mosquitoes, which are at home.
El Salvador: A worker of the Ministry of health fumigated a private apartment, in order to combat mosquitoes
It is unclear, however, whether the Virus is genetically changed, that it spreads easier and is more dangerous. Or if rare complications occur simply only revealed when more people are affected.
“The Virus attacks, preferably, the nerve tissue and damage it,” says Eisermann. In adults, infection in rare cases, leads to an inflammatory disease of the nerves called Guillain-Barré syndrome. In the case of Unborn Zika can cause severe neurological damage and a malformation of the brain. The babies often have a very small head called Microcephaly. “These serious problems were seen in 2015 for the first Time,” says Eisermann.
In the Video: How dangerous are the Zika Virus?
Problems with the eyes, hearing, language
Exactly how the Virus makes you sick, scientists are still. A study by the Technical University of Munich and the Max-Planck-Institute for biochemistry, according to the Virus could take advantage of proteins of the human cell to reproduce their genetic material. These proteins are exhausted, not able to form stem cells to nerve cells – the brain does not develop correctly. “The exact way how a Microcephaly develops after an infection, we don’t know but still,” says Drexler.
To better assess on the other hand, how often a infection of the mother causes damage to the child. “At the beginning of the data between quite a few up to 42 percent,” says the virologist fluctuated. Now it is about five to seven percent – where the risk is, especially in the first Trimester large. “The Microcephaly is only the tip of the iceberg,” says Drexler.
Researchers at the University of California in Los Angeles studied in a recent publication of the 216 children whose mothers were infected during pregnancy, about a mosquito bite with the Virus. A third development was delayed, had problems with the eye or the ear. Cognitive, motor or language development deficits were also children who were born with an average head circumference. Two-thirds was unremarkable.
New outbreak is not unlikely
For the scientists a mystery why 95% of all reported Microcephaly cases originate from the North-East of Brazil, however, is still – while the virus in other areas, a similar number of people infected. “Why only get Brazilians from this Region is an abnormal form of a child? There was a Co-infection? Vaccinated mothers in a different way? We don’t know it’s simple,” says Drexler.
Where and when the Zika Virus flares up again, you can’t predict. The WHO has lifted the global health emergency in November 2016. “That it comes to an outbreak, but it is not unlikely,” says Eisermann. “The Virus is out of the way, you can be infected in Africa, Asia or South America with it.” In 2017, there was an apparently long period of time unnoticed larger wave of Illness in Cuba, Peru reports that currently the cases.
Better prepared for further Zika-wave
“There you go Again,” says Drexler. The Virus had migrated from South America to Africa. What Zika is doing there, or even in Asia, is unclear, the reporting systems in the areas of work badly. Also in South America, the Virus could flare up in regions with low herd immunity again. “The mobility has increased, we drag Pathogens around the globe,” says Drexler. “Outbreaks we will see very likely more and more often.”
Physicians Eisermann, however, is convinced that Better prepared you are in each and every case. Due to the emergency in Brazil a lot of money has been invested in the Zika-research. The diagnostic Tests are progressed, though still not perfect. An acute infection is in the body, slightly above the genetic material of the Virus in the blood and urine evidence. However, this is only about a week after the appearance of the first symptoms is possible. After infection through antibodies is observed. Here are the Tests, but are still error-prone. Vaccine candidates there are several, but none is ready for market. The Situation is similar in the case of drugs against the disease.
Also in Abidjan in the ivory coast escorts went with special Sprays against mosquitoes, the Zika-contain Virus
Nevertheless, it Was Zika classified – once as a global threat – in the danger overstated? And other, more dangerous viruses such as the causative agents of Dengue fever have been neglected in the research? “That may be the case, but here you can catch up again,” says Eisermann.
Drexler finds the response suitable. “The situation in South America has been dramatic.” Not least, the Zika-research also help, more about other viruses and their Interaction to find out. The Charité has established a virologist and his Team that a previous infection with a Dengue virus damages, more than a degree of protection against Zika-and this is not, as once believed, still aggravated.
Eisermann is that you have to distinguish: “For adult Zika may continue to be a relatively harmless Virus,” he says. The most contagious run turns mild. “The knowledge that it may harm unborn children is difficult, however, makes it a dangerous pathogen.”