Zika Virus Infection
Causative agent
Zika virus infection is a mosquito-borne disease caused by Zika virus.
Clinical features
Most Zika virus infection is asymptomatic. For patients with symptoms, they commonly present with skin rash, fever, conjunctivitis, muscle or joint pain and general malaise. These symptoms are usually mild and last for a few days.
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.
Mode of transmission
Zika virus is mainly transmitted to humans through the bite of an infected Aedesmosquito. Aedes aegypti, which is currently not found in Hong Kong, is considered the most important vector for Zika virus transmission to humans. Other Aedes mosquito species such as Aedes albopictus which is commonly found in Hong Kong are also considered as potential vectors.
Zika virus 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.
Incubation period
The incubation period of Zika virus infection ranges from 3 – 14 days.
Management
There is no specific medication for Zika virus infection and the mainstay of treatment is symptomatic relief and prevention of dehydration. If symptoms worsen, they should seek medical care and advice.
Prevention
At present, there is no effective vaccine against Zika virus infection. To prevent Zika virus infection, members of the public are reminded to protect themselves from mosquito bites and help prevent mosquito proliferation. The public is also advised to take precautions to prevent sexual transmission of Zika virus.
As the impact of Zika infection on the pregnant woman and her foetus is still evolving, you are advised to refer to the website of Centre for Health Protection for the latest information. http://www.chp.gov.hk/en/content/9/24/43088.html
Beware of Zika Virus Infection
Special notes for pregnant women and women preparing for pregnancy
- Should not travel to areas with Zika virus transmission*
- Those who must travel to any of these areas should arrange consultation with a doctor at least six weeks before the trip
- 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 travelers including pregnant women
- 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
Prevention of sexual transmission#
Special notes for All
- Travellers should consider not having sex during travel to affected areas, or else condoms should be used
- 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
- 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
# 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
* Please refer to CHP website for most updated information on Zika Virus Infection.