The fast evolving Zika virus could become more infectious evade pre-existing immunity, warn scientists.

Symptoms of the virus are usually mild in adults however it can infect a developing foetus leading to a range of serious birth defects including Microcephaly and other congenital abnormalities.

Widespread outbreaks of the mosquito-borne virus have been recorded since 2007 and in 2015 a global medical emergency was declared following an outbreak that started in Brazil and quickly spread across the globe.

Now researchers at La Jolla Institute for Immunology (LJI) have found that it is relatively easy for Zika virus to acquire a single amino acid change that allows it to make more copies of itself  and help infections take hold more easily.

Banbury Cake: An image showing a transmission electron micrograph of the Zika virus (CDC/PA)An image showing a transmission electron micrograph of the Zika virus (CDC/PA)

What is the Zika virus? 

Zika virus is transmitted primarily by Aedes mosquitoes, which bite during the day.

First identified in monkeys in 1947, Zika virus was later identified in humans in 1952 and rare sporadic cases of human infections were found across Africa, the Americas, Asia and the Pacific.

It can lead to serious birth defects and although symptoms are usually mild in adults it can trigger Guillain-Barré syndrome, neuropathy and myelitis.

What are the symptoms of Zika virus?

Symptoms are generally mild including fever, rash, conjunctivitis, muscle and joint pain, malaise, and headache, and usually last for two to seven days; however most people do not develop symptoms. 

Virus 'linked to birth defects in almost 30 countries'

However, the virus can lead to serious defects if it infects a developing foetus. The infection has been linked to birth defects in almost 30 countries, including microcephaly, where babies are born with abnormally small heads and restricted brain development.

Zika infection in pregnancy also results in pregnancy complications such as foetal loss, stillbirth, and preterm birth. 

The World Health Organisation (WHO) states that infection is also a trigger of Guillain-Barré syndrome, neuropathy and myelitis, particularly in adults and older children.

What treatment is there for the Zika virus? 

There is no treatment available for Zika virus infection or its associated diseases.

Pregnant women living in areas with Zika transmission or who develop symptoms of Zika virus infection should seek medical attention for laboratory testing and other clinical care.  

Protection against mosquito bites during the day and early evening is a key measure to prevent Zika virus infection. 

How is the virus transmitted?

Zika virus is primarily transmitted by the bite of an infected Aedes mosquito in tropical and subtropical regions. 

Banbury Cake: A mosquito feeding on a human host (Jim Gathsny/CDC/PA)A mosquito feeding on a human host (Jim Gathsny/CDC/PA)

This is the same mosquito that transmits dengue, chikungunya and yellow fever.

It is also transmitted from mother to fetus during pregnancy, through sexual contact, transfusion of blood and blood products, and organ transplantation.

How much of a threat is the Zika virus to the UK?

Zika virus is found in parts of:

  • South and Central America
  • the Caribbean
  • the Pacific islands
  • Africa
  • Asia

The type of mosquitoes that carry Zika virus are not found in the UK.

According to WHO, the Zika virus is present in more than 87 countries. As of 2020, virus activity continues in the Caribbean, most of Latin America, Central Africa, India, Indonesia, Malaysia, Cambodia, and Papua New Guinea, among other places.