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Zika Virus Infection

Zika Virus Infection

Zika virus infection is a cause of microcephaly and Guillain-Barré syndrome

The Alert Response Level under the Government's Preparedness and Response Plan for the Zika Virus Infection is activated

Zika virus infection is a mosquito-borne disease caused by Zika virus. The symptoms of Zika virus infection include skin rash, fever, conjunctivitis, muscle or joint pain and general malaise.

The current major concern is the association with adverse pregnancy outcome (microcephaly) and neurological and autoimmune complications such as Guillain-Barré syndrome (GBS). The World Health Organization has concluded that Zika virus infection during pregnancy is a cause of congenital brain abnormalities, including microcephaly, and that Zika virus is a trigger of GBS.

Apart from GBS, acute disseminated encephalomyelitis (a disease of the central nervous system) was found to be one of the neurologic manifestations possibly resulted from Zika virus infection.

Zika virus is mainly transmitted to humans through the bite of an infected Aedes mosquito. It has also been found in human semen and transmission by sexual contact has been confirmed. Sexual transmission of Zika virus between men who have sex with men has been documented in the literature. Other modes of transmission such as blood transfusion and perinatal transmission are possible.

Microcephaly and Zika virus 

Prevention of sexual transmission*

  1. Travellers should consider not having sex during travel to areas with Zika virus transmission (affected areas) , or else condom should be used.  
  2. Male and female travellers returning from affected areas should abstain from sex for at least 3 months and at least 2 months respectively upon return, or else condom should be used.
  3. Pregnant woman should not have sex with her partner who had travelled to affected areas, or else condom should be used throughout the pregnancy.

*This precautionary measure may be revised as more information becomes available. Individuals with further concerns regarding potential sexual transmission of Zika virus should contact their doctor for advice.

Pregnant women should not travel to areas with Zika virus transmission. Women preparing for pregnancy should note Points A and B above. If they or their male sex partners plan to travel to affected areas, they should consult their doctors for advice on the risk. Use of mosquito repellent containing DEET during travel and returning from these areas for a period of at least 21 days are advised for all travellers including pregnant women.

Pregnant women are advised to:

  • attend antenatal follow up regularly and tell the attending doctor history of recent travel;
  • observe for symptoms of Zika virus infection and seek medical advice as soon as possible if feeling unwell;
  • abstain from sex with her partner who had travelled to affected areas, or else condom should be used throughout the pregnancy.

For details on prevention of Zika virus infection, including those for pregnant women, women preparing for pregnancy and travellers going to affected areas, please refer to the factsheet of Zika Virus Infection.

For other languages [हिन्दी (Hindi), नेपाली (Nepali), اردو (Urdu), ไทย (Thai), Bahasa Indonesia and Tagalog], please click here

For details on screening of blood donors to prevent Zika virus infection, please refer to Hong Kong Red Cross Blood Transfusion Service website. For further details, donors may enquire through hotline: 2710 1234.



Preparedness and Response Plan


Areas with Zika virus transmission


General measures on preventing mosquito bites and mosquito breeding


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