The National Institute for Communicable Diseases (NCID) believes South Africa isn't likely to be at risk of the Zika virus (ZIKV) – which is "spreading explosively" in the Americas, according to a warning by the World Health Organisation (WHO).
- When and where did the Zika virus originate?
The Zika virus (ZIKV) was first isolated from the rhesus monkey in the Zika forest in Uganda in 1947, and from humans in Nigeria in 1968.
- How is it transmitted?
ZIKV is transmitted to humans by a certain daytime-active Aedes aegypti mosquitoes. These mosquitoes also play a role in the transmission of other viruses such as dengue fever, yellow fever, and the chinkungunya virus in certain settings.
Although, some travellers infected with the Zika virus, may return to South Africa, they don’t pose any risk to the local population. These viruses are not contagious and usually require the assistance of a mosquito vector between hosts.
- Is this a new virus?
No. Prior to 2015, outbreaks of ZIKV were intermittently reported in a narrow equatorial band extending from Central Africa through Southeast Asia to the Pacific Islands.
In 2015, the Pan American Health Organisation (PAHO), issued an alert regarding the first confirmed ZIKV infections in Brazil. Since then, 18 countries in the Americas have confirmed cases of the Zika virus.
The Brazilian outbreak appears to be associated with the lack of piped water, and the consequent storage of water in indoor vats and pails, which are all ideal habitats for Aedes aegypti mosquitoes to breed in.
- What are the symptoms?
The most common symptoms of illness from the Zika virus disease (ZVD) include an acute onset of:
- joint pain, and
- conjunctivitis (red eyes).
About 1 in 4 people infected are symptomatic. The illness itself is usually relatively mild and persists for up to a week. Severe illness from the virus, which would require hospitalisation, is rare.
- What is the treatment?
Currently, there is no vaccine or specific medicine to treat ZIKV infections.
- How do I treat the symptoms of ZIKV?
If you are starting to show any of the common ZIKV symptoms, you can treat them by:
- getting plenty of rest,
- drink fluids to prevent dehydration,
- taking medicine such as acetaminophen to reduce fever and pain, and
- not taking aspirin or other non-steroidal anti-inflammatory drugs.
If you’re taking medicine for another medical condition, talk to your doctor before taking additional medication. If symptoms worsen, you should seek medical care and advice.
- What preventative measures can I take?
Mosquitoes and their breeding sites pose a significant risk factor for ZIKV infection. Prevention and control relies on reducing mosquitoes through source reduction (removal and modification of breeding sites) and reducing contact between mosquitoes and people.
This can be done by:
- using insect repellent,
- wearing clothes (preferably light-coloured) that cover as much of the body as possible,
- using physical barriers such as screens, closed doors and windows, and
- sleeping under mosquito nets.
It’s also important to empty, clean or cover containers that can hold water such as buckets, flower pots or tyres, so that places where mosquitoes can breed are removed.
- Does ZIKV infection in pregnant women cause birth defects?
There have been reports of a serious birth defect of the brain called microcephaly (a condition in which a baby’s head is smaller than expected when compared to babies of the same sex and age) and other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant.
Knowledge of the link between Zika and these outcomes is still developing and ongoing, however, we recommend these special precautions for the following groups:
- Women who are pregnant (in any trimester):
- Consider postponing travel to any area where ZIKV transmission is ongoing.
- If you must travel to one of these areas, talk to your doctor first and strictly follow steps to prevent mosquito bites during your trip.
- Women who are trying to become pregnant:
- Before you travel, talk to your doctor about your plans to become pregnant and the risk of ZIKV infection.
The NCID has warned pregnant women not to travel to the Americas, where the virus is spreading rapidly. If you’re travelling, you should speak to your doctor, and follow the steps to prevent mosquito bites during your trip.
- What are the risks for ZIKV being introduced in South Africa?
It’s important to emphasize that in Africa, ZIKV has not to date been found further south than Uganda.
Although the possibility of an infected traveller introducing ZIKV to South Africa exists, the short viraemic period (virus present in bloodstream) would lessen the chance of transmission to a susceptible mosquito, particularly because the Aedes aegypti mosquitoes found in South Africa are slightly different than those spreading ZIKV in the Americas, have very limited flight ranges and tend not to enter buildings.
- What next?
The Western Cape Department of Health has notified healthcare workers about ZVD and have introduced indications for testing in:
- returning travellers with symptoms (listed above), and
- recent travel (within 14 days) to an active transmission area.
Personal protection to avoid mosquito bites is essential for travellers visiting areas where ZIKV is circulating.