Zika virus: What is the disease linked to babies being born with smaller heads?

Over 3,000 babies have been born with the virus in Brazil since October 2015

A baby in Hawaii has become the first person in the US to be born with the Zika virus, which is believed to cause brain damage and a child's head to grow smaller than expected. 

The infant born in Oahu hospital was also the first birth in the US to have microcephaly - the term for used to describe the head appearing shrunken - the US Centers for Disease Control and Prevention said on 17 January. 

Medics believe that the baby’s mother contracted the disease spread by mosquitos when she was visiting Brazil. 

Officials have sought to reassure the public that neither the baby nor the mother is infectious, and there is no risk of transmission in Hawaii.

While research into the virus is minimal, agencies who are investigating the disease have a growing body of evidence which suggests that Zika causes microcephaly, but more research is needed to uncover the full extent, according to the World Health Organisation (WHO).

Below is everything you need to know about the disease and how to protect yourself. 

Where am I most at risk of catching Zika?

The largest outbreak of the virus is currently unfolding in Brazil, where it has been linked to a surge in birth defects such as microcephaly. 

Since October 2015, 3,530 babies have been born with microcephaly in Brazil, mainly in the poor north east, while fewer than 150 such cases were seen in all of 2014, according to the country’s Health Ministry. 

The virus is known to circulate in Africa, the Americas, Asia and the Pacific.

How is it spread?

The Zika virus is spread by the bite of the Aedes aegypti mosquito, which can also carry dengue and chikungunya. 

Should I be concerned? 

The US Centers for Disease Control and Prevention  recently issued an alert advising pregnant women and those trying for a baby to take “enhanced precautions” to avoid mosquito bites in Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Suriname, Venezuela, and the Commonwealth of Puerto Rico. The UK Foreign Office has released similar warnings. 

What are the symptoms?

The signs of the virus can include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache. Such symptoms generally last for 2 to 7 days. 

How is it treated?

There is currently no treatment or vaccine available for Zika, according to the WHO.

The symptoms generally pass in a few days, and those with the disease are advised to rest, drink plenty of fluids, and use pain killers if necessary. If the symptoms become worse, a doctor should be consulted. 

How can I protect myself?

The best way to avoid the virus is to protect yourself against mosquito bites. Using insect repellent; wearing light-coloured clothes that cover the body; blocking mosquitos by wearing sun screen, closing doors and windows, and sleeping under mosquito nets can reduce the risk of being bitten.  

The WHO also recommends ensuring mosquotis do not have a place to breed, but emptying and cleaning out containers that can hold water, such as buckets, flower pots or tyres. 

Additional reporting by AP