In 9 months, more than 3,000 cases of microcephaly have been reported in Brazil. This congenital malformation is believed to be linked to infection with the Zika virus.
Since the spring of 2015, the Zika virus has been shaking South America and the Caribbean. In this part of the world, reports are increasing as fast as the spread of the virus by mosquitoes.
In less than a month, 12 cases were confirmed in Martinique and 150 suspected cases were seen in consultation. In Guyana, 17 people were also infected.
But it is in Brazil that the Zika virus is wreaking most havoc. In 9 months, between 440,000 to 1,300,000 suspected cases were reported by Brazilian health authorities. And while the infection with this virus was thought to be mild, more than 3,000 newborns infected during pregnancy suffer from microcephaly compared to 150 in previous years. Infants are born with a head circumference less than 33 centimeters and irreversible mental retardation.
An unprecedented situation that forced the country to declare a state of health emergency in December 2015. Since then, Brazilian women live in fear of being bitten by a mosquito and infecting their child.
An uncertain link
In view of the Brazilian situation, French Polynesia has again analyzed the health registers for 2013-2014, the year of the epidemic. The authorities then found an increase in microcephaly that had gone unnoticed at the time.
In addition, Brazilian authorities have found the virus in a deceased baby with this malformation and in the amniotic fluid of several pregnant women. However, the link between Zika and microcephaly is uncertain.
“Are these abnormalities due only to the Zika virus, or to the joint circulation of other infectious agents or to other factors?” Multidisciplinary research projects must be set up to try to answer these questions, ”explained Dominique Rousset, head of the virology laboratory and of the National Arbovirus Reference Center at the Institut Pasteur in Guyana during the publication this Friday of the complete genetic sequence of this viral strain.
In fact, the Zika virus is transmitted by mosquitoes Aedes aegypti, originally from Africa. Aedes albopictus, the tiger mosquito, could also be a vector of the Zika virus, as it already is for dengue and chikungunya. Malformations could therefore be caused by these infectious agents.
Also, to better understand this infection and know this virus, a team of 4 researchers from the Pasteur Institute in Dakar arrived in Sao Paulo on Tuesday to help Brazilian scientists.
Microcephaly: a neurological malformation that cannot be cured
During pregnancy, the first neurons are put in place at lightning speed. Until the 17th week of gestation, 250,000 neurons form in one minute and create connections.
But, in case of microcephaly caused by a genetic mutation or an environmental factor (alcohol, certain drugs or a viral infection …), the formation of the brain is limited. The perimeter of the head of these children is then less than normal. This anomaly is most often detected during pregnancy during an ultrasound. But it is already too late.
There are different forms of microcephaly and not all of them are very well known. The future of children is therefore difficult to predict. Nevertheless, all will be affected by mild to very severe mental retardation, will have learning difficulties, speech or motor problems.
Thanks to early speech therapy and psychomotor rehabilitation, the neuronal development of these children is promoted. They allow them to acquire a certain autonomy and to evolve at their own pace.
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