Background
Zika virus, a single stranded RNA virus, is transmitted primarily through infected Aedes aegypti mosquitoes. Zika virus can also be transmitted through unprotected sex with an infected partner or from mother to fetus during pregnancy.
Clinical features of Zika virus infection
The incubation period is around 3-14 days. Symptoms are present in about 20% of those who are infected, and the symptoms are nonspecific, including fever, rash, muscle and joint pain.
Complications
- Zika virus can be transmitted from mother to fetus during pregnancy, resulting in microcephaly (smaller than normal head size) and other congenital malformations in the infant, collectively referred to as Congenital Zika Syndrome. Microcephaly is caused by underlying abnormal brain development or loss of brain tissue. Child outcomes vary according to the extent of the brain damage. Congenital Zika Syndrome also includes other malformations such as limb contractures, high muscle tone, eye abnormalities, and hearing loss. The risk of congenital malformations following infection in pregnancy remains unknown; an estimated 5–15% of infants born to women infected with Zika virus during pregnancy have evidence of Zika-related complications. Congenital malformations occur following both symptomatic and asymptomatic infections.
- Guillain-Barre Syndrome and other neurological conditions including meningitis, meningoencephalitis and myelitis.
Prevention
- At present, avoid exposure is the best.
- The Department of Health and the Hong Kong Council on Human Reproductive Technology of HKSAR advise that pregnant women and women preparing for pregnancy should not travel to areas with Zika virus transmission (affected areas). In order to avoid sexual transmission, travellers should consider not having sex during travel to affected areas, or else condom should be used. Male and female travellers returning from affected areas should consider abstinence from sex for at least 3 months and at least 2 months respectively upon return, or else condom should be used. Pregnant women should not have sex with her partner who had travelled to affected areas, or else condom should be used throughout the pregnancy.
- During their stay in the outbreak areas, travellers should strictly follow steps to avoid mosquito bites during day and night including (a) the use and reuse of Environmental protection Agency (EPA)-approved insect repellents with DEET as directed on the product label, (b) wearing light-colored, loose, long- sleeved skirts and pants to cover exposed skin, (c) avoid using fragrant cosmetics or skin care products, (d) staying in air-conditioned or screened-in areas, and (e) treating clothing (but not skin) with permethrin. Both DEET and permethrin can be used safely during pregnancy.
- After returning from outbreak areas, travellers should continue steps to avoid mosquito bites including applying mosquito repellent for 21 days to prevent human- to- mosquito- to- human transmission.
Management
Zika virus disease is usually relatively mild and requires supportive treatment which includes rest, fluids, and treating pain and fever with panadol. Aspirin and other non-steroidal anti-inflammatory drugs should be avoided until Dengue Fever (with similar symptoms as Zika but with potential bleeding complications) is excluded. If symptoms worsen, seeking medical care and advice is recommended. There is no antiviral agent or vaccine available.
**For couples trying to conceive or planning to have fertility treatment**
Couples should avoid travelling to areas with Zika outbreaks. Check the related information before travel.
More information about Zika virus infection can be obtained from the website of the Department of Health:
https://www.chp.gov.hk/en/healthtopics/content/24/43088.html
A list of areas with Zika virus infection can be found at:
https://www.chp.gov.hk/en/features/43209.html
https://www.gov.uk/guidance/zika-virus-country-specific-risk#atoz
