Zika virus has recently emerged as one of the most challenging threats to human health. It can cause microcephaly, a condition where a baby has  a smaller than normal head and brain, among infants born to infected women, as well as neurological disorders such as Guillain-Barré syndrome. Since early 2015, Zika has spread rapidly through the Americas and active transmission is now present in over thirty countries and territories.


According to the CDC, many people infected with Zika do not show symptoms so may not know that they have the virus. When symptoms do occur, they are usually mild and last for a few days to a week. Symptoms include fever, skin rashes, conjunctivitis, muscle and joint pain, and headache.

However, Zika can also cause neurological birth defects such as microcephaly in babies born to infected mothers. The virus has been associated with meningoencephalitis, a dangerous inflammation of the membranes that surround the brain. Zika infection can also result in Guillain-Barré syndrome, a disorder in which the body’s immune system attacks its nerve cells and can lead to paralysis in adults.


Zika was originally identified in Uganda in 1947, and the first major outbreaks occurred in the Pacific, on Yap Island in 2007 and French Polynesia in 2013.

In 2015 an outbreak was reported in Brazil, and in December of that year the Pan American Health Organization/World Health Organization (PAHO/WHO) issued an epidemiological alert given the apparent link between Zika infections and increase in babies born with neurological syndromes. On 1st February 2016, the WHO declared a Public Health Emergency of International Concern and urged aggressive implementation of vector control measures to manage the outbreak.­

Zika has now spread to a large number of countries in the Americas, as well as some Pacific Islands and countries in Southeast Asia. The link between Zika and neurological disorders in babies was confirmed by the CDC in April 2016.


There is currently no vaccine for Zika, so control of the mosquito and avoidance of bites are the best ways to combat the disease. Sexual transmission of the Zika virus has also been described in certain cases and so those who have visited areas with Zika should follow CDC advice on preventing sexual transmission.

Further information

WHO Zika factsheet

CDC: Zika