What is the Zika Virus?

Zika virus is spread to people through mosquito bites. The most common symptoms of Zika virus disease are fever, rash, joint pain, and red eye. The illness is usually mild with symptoms lasting from several days to a week. Severe illness requiring hospitalization is uncommon.

Outbreaks of Zika have occurred in Africa, Southeast Asia, and the Pacific Islands.

The Aedes species mosquitoes that spread Zika virus are found throughout the world, however, most cases of Zika have been reported in returning travelers.

There is no vaccine to prevent or medicine to treat the Zika virus.



Through mosquito bites

The Zika virus is transmitted to people primarily through the bite of an infected Aedes species mosquito. These are the same mosquitoes that spread dengue and chikungunya viruses.

  • These mosquitoes typically lay eggs in and near standing water in things like buckets, bowls, animal dishes, flower pots and vases.  They are aggressive daytime biters, prefer to bite people, and live indoors and outdoors near densely populated areas.
  • Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites.


Rarely, from mother to child

  • A mother already infected with Zika virus near the time of delivery can pass on the virus to her newborn around the time of birth, but this is rare.
  • To date, there are no reports of infants getting Zika virus through breastfeeding.

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Possibly through infected blood or sexual contact

  • In theory, Zika virus could be spread through blood transfusion. To date, there are no known reports of this happening.
  • There has been two reports of possible spread of the virus through sexual contact.

ZIKA Virus and Pregnancy

Pregnant women have the same risk as the rest of the population of being infected with Zika virus, which is transmitted by the  bite of infected Aedes mosquitoes.

Many women may remain unaware they have the virus, as they may not develop any symptoms.

Only one in four people infected with Zika develops symptoms, and in those with symptoms the illness is usually mild.

Research is being done to determine what effects Zika can have on fetuses.

On 28 November 2015, the Ministry of Health of Brazil established a relationship between an increase in cases of microcephaly in newborns and Zika virus infections in the country’s northeast.

According to a preliminary analysis of research carried out by Brazilian authorities, the greatest risk of microcephaly and malformations appears to be associated with infection during the first trimester of pregnancy.

PAHO/WHO urges women who are pregnant or planning to become pregnant to seek prenatal care to receive information and monitoring of their pregnancy and to follow their doctors’ recommendations.

Press Release: Ministry of Health is Advising Women to Delay Pregnancy in Light of Zika Virus Links to Birth Defects

More from JIS: PAHO and WHO Question and Answers: Zika and Pregnancy


Symptoms & Treatment


  • About 1 in 5 people infected with Zika virus become ill (i.e., develop Zika).
  • The most common symptoms of Zika are fever, rash, joint pain, or red eyes. Other symptoms include muscle pain, headache, pain behind the eyes, and vomiting.
  • The illness is usually mild with symptoms lasting for several days to a week.
  • Severe disease requiring hospitalization is uncommon.
  • Deaths due to Zika have not been reported.


  • The symptoms of Zika are similar to those of dengue and chikungunya, which are diseases caused by other viruses spread by the same type of mosquitoes.
  • See your healthcare provider if you develop the symptoms described above.
  • If you have recently traveled, tell your healthcare provider.
  • Your healthcare provider may order blood tests to look for Zika or other similar viruses like dengue or chikungunya viruses.


  • There is no medicine to treat Zika.
  • Treat the symptoms:
    • Get plenty of rest
    • Drink fluids to prevent dehydration
    • Take medicines, such as acetaminophen or paracetamol, to relieve fever and pain
    • Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided until dengue can be ruled out to reduce the risk of hemorrhage


Reduce the risk of getting Zika

There is no vaccine to prevent Zika Fever (Zika Virus Infection). The best prevention is to:

  1. Reduce or eliminate mosquito breeding sites as follows:
  • Check premises weekly for water-filled containers.
  • Throw away or recycle water containers that are not needed.
  • Containers such as drums should be fully and tightly covered, turned over or placed under a roof that does not allow them to fill with water.
  • Clean and scrub flower vases and pet’s water containers weekly and dump the water from overflow saucers under potted plants and flower pots.
  • Clear roof gutters and eaves to prevent water from settling.
  • Fill tree holes and other cavities in plants with soil or sand.
  • Repair leaking pipes and outside faucets

2. Protect yourself from mosquito bites by:

  • Using a mosquito repellent that contains DEET, IR3535 or Icaridin
  • Sleeping under a mosquito net
  • Wearing light coloured clothing and cover body as much as possible


Geographic Distribution

Outbreaks of Zika virus disease (or Zika) previously have been reported in tropical Africa, Southeast Asia, and the Pacific Islands. Zika virus likely will continue to spread to new areas. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infections in Brazil.

The map below shows the global distribution of the Zika Virus from the Centres for Disease Control and Prevention as at January 22, 2016



History of the Zika Virus 

The Zika virus was first isolated in 1947 in Zika Forest (Uganda), in a Rhesus monkey during a study of the transmission of wild yellow fever.

It was first isolated in humans in 1952 (Uganda, Tanzania). In 1968 the virus was detected in human samples in Nigeria. In 2007 the first major outbreak of Zika virus fever occurred on the island of Yap (Micronesia) where 185 suspected cases were reported, of which 49 were confirmed and 59 were considered probable. The outbreak lasted 13 weeks (April to July).

Subsequently there was an outbreak in French Polynesia, which began at the end of October 2013. Around 10,000 cases were registered, of which approximately 70 were severe cases, including neurological or autoimmune complications.

To date, no death attributed to Zika virus infection has been reported in any of the outbreaks.



Zika Virus Related Stories on the JIS 

Centres for Disease Control and Prevention: Zika Virus  

Ministry of Health: Frequently Asked Questions on Zika Fever 

PAHO and WHO Questions and Answers: Zika and Pregnancy


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