Zika Virus infection is caused by the Zika Virus (ZIKV) belonging to the Flaviviridae family. The virus is primarily transmitted by infected daytime biting female Aedes aegypti and Aedes albopictus mosquitoes which are typically active from dawn to dusk. There is evidence that Zika Virus is also transmitted by other mosquitoes belonging to the Aedes genus.
The virus can be transmitted from a pregnant woman to her fetus. Human transmission can also occur through unprotected vaginal, anal or oral sex. In some patients, researchers have found that the virus can be shed through saliva and urine.
Zika Virus is present in Mexico, Central America, South America, the Caribbean, tropical areas of Southeast Asia, Oceania, and parts of Africa. All travellers are at risk. Long-term travellers and aid or missionary workers going to areas where Zika Virus is endemic are at greater risk.
Information about the virus is continuously evolving. However, there is strong scientific consensus that Zika Virus causes neurological complications: Guillain-Barré syndrome (progressive muscle weakness that can lead to temporary paralysis) and microcephaly (decreased head size which may lead to developmental delays) in infants born to pregnant women infected with the virus.
In the majority of cases, Zika Virus infection is asymptomatic – persons do not exhibit symptoms. Those with symptoms usually get ill 3-12 days after being bitten by an infected mosquito. Symptoms include mild fever, headache, muscle and joint pain, nausea, vomiting, and general malaise. The illness is characterized by pink eye (inflammation of the conjunctiva), a skin rash with red spots on the face, neck, trunk, and upper arms which can spread to the palms or soles, and sensitivity to light. Some may also have a lack of appetite, diarrhea, abdominal pain, constipation, and dizziness. Most people fully recover from the illness within 7 days. Treatment includes supportive care of symptoms. There is no antiviral treatment available.
Travellers going to areas with Zika Virus should take meticulous measures to prevent mosquito bites during the daytime. There is currently no preventive medication or vaccine against Zika Virus.
Travellers who are pregnant or considering pregnancy should postpone travel to areas with Zika Virus transmission.
To avoid sexual transmission of the virus to a pregnant partner, travellers who have been in areas with risk of Zika Virus transmission should practice safe sex for the duration of the pregnancy.
All travellers, particularly partners considering pregnancy, should practice safe sex or abstinence for at least 6 months if one or both partners have travelled to an area with risk of Zika Virus transmission. Practicing safe sex is recommended even if you or your partner do not have symptoms. Most Zika Virus infections are asymptomatic (show no signs or symptoms), but transmission of the virus to another person can still occur.
If you travel to or live in an area with risk of Zika virus transmission, follow meticulous mosquito bite prevention measures during the daytime.
Health risk description last reviewed: February 26, 2018
Country information last updated: September 11, 2018