healthHealth and Medicine

Virus That Shrinks Babies' Skulls Is Rapidly Spreading Through The Americas


Robin Andrews

Science & Policy Writer

440 Virus That Shrinks Babies' Skulls Is Rapidly Spreading Through The Americas
The virus is spread by the Aedes aegypti mosquito. mrfiza/Shutterstock

You probably haven’t heard of the Zika virus, which among other things causes babies to be born with abnormally small brains. Belonging to the Flaviviridae family, it is nowhere near as well-known as many other familial viruses, including those that cause yellow, dengue, and West Nile fevers. However, the Zika virus is certain to make headlines this week: it is beginning to spread rapidly across South America, according to The Independent.

First isolated in a rhesus monkey in 1947 in the Zika Forest of Uganda, the eponymous virus is spread through mosquitos of the Aedes genus to many kinds of primates, including humans. Headaches, a body rash, fever, and joint pain are all associated with a Zika virus infection. Although this may not sound particularly dangerous, mothers infected with the virus can produce newborns that suffer from incurable microcephaly – those with dramatically shrunken craniums.


The global spread of the disease outside of Uganda has been continuing for some time, but the virus has recently experienced a surge in successful infections, particularly in South America. In terms of babies born with associated microcephaly, there were only 147 new cases documented in Brazil in 2014; last year, there were 2,782 cases, 40 of which have died. All surviving babies are likely to suffer from impaired intellectual development in adulthood, and will require lifelong care.

MRI scans of a normal individual (left) and one with microcephaly (right). Credit:  Ayacop/Wikimedia Commons; CC BY 2.5

No-one is entirely sure how the virus made its way to Brazil, although several theories have been put forward. Most prominently, the huge influx of global travelers to the country during the 2014 World Cup has been purported to have brought the virus with it. Either way, Brazilian researchers are concerned that Zika is infecting those with no experience of it, and therefore no immune system response to it. In addition, the warm, humid environments of Brazil may be helping the transmitting mosquito to flourish.

As with any outbreak, fear and confusion is spreading along with the virus itself. Although the Brazilian government isn’t quite telling women not to get pregnant – the evidence connecting the virus to microcephaly is not completely clear just yet – some scientists are advising women to delay pregnancy if they can until the outbreak can be stemmed. The Ministry of Health of Brazil has declared a national public health emergency, giving authorities and medical agencies greater flexibility to the investigations.


“The situation is incredibly frightening,” said Andreza Mireli Silva to The New York Times. She is a 22-year-old worker in a shoe factory in Sergipe State in northeast Brazil who is seven months pregnant, and as such she is considered in the highest risk group. She is applying insect repellant every three hours and is wearing long pants despite the searing summer heat, all to avoid any mosquito bites.

The outbreak hasn’t just spread within Brazil: Puerto Rico is the most recent nation to declare that it has detected at least one case of the Zika virus within its borders. Since October of last year, the infection has been diagnosed in Colombia, El Salvador, Guatemala, Mexico, Paraguay, Panama, Suriname and Venezuela. Nevertheless, Brazil, for now, appears to be bearing the brunt of the associated microcephaly outbreaks, most of which are occurring in the northeastern state of Pernambuco.


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