Zika made headlines when it broke out in Brazil in 2015, and 3 762 babies were born with small, misshapen heads and underdeveloped brains. Although the Asian strain linked to this has been brought under control there, it is reported to be spreading quietly through South America and into Central America.
It grabbed headlines again last in October this year when the Duke and Duchess of Sussex, Prince Harry and his pregnant bride Meghan, opted to go ahead with a visit to Fiji and Tonga in spite of a foreign office guidance that pregnant women should not visit the region because Zika cases were occurring there.
Now it has emerged that the same Asian strain may have surfaced in Africa for the first time – in Angola, just over the border from South Africa.
How concerned should you be?
Zika virus is spread by the bite of an infected Aedes aegypti mosquito – the kind that also spreads dengue fever. Unlike other mosquitoes, they bite mostly during the day. And once someone is infected, they can pass on the virus to others through sexual contact; it can also be transmitted from a pregnant mother to her child, and through blood transfusions.
There is at present no drug treatment or vaccine for Zika. “Treatment, as for most other viral infections, is support care to manage the symptoms,” says Nevashan Govender, head of the emergency operations centre at the National Institute for Communicable Diseases (NICD).
But in most cases the effects of Zika are mild, flu-like symptoms that last only a day or two – fever, possible skin rash, conjunctivitis, pain in the muscles and joints, tiredness and headache. It is only when there are complications or the person is immune-suppressed due to an additional disorder that problems arise, Govender says.
Zika is suspected to be linked to a number of neurological disorders, including Guillain-Barre syndrome, where the immune system attacks the nerves, resulting in muscle weakness and possible paralysis; and microcephaly, the birth defect where babies are born with small heads, sight and hearing problems and learning disabilities.
Before South Africans panic, they should to know that Zika originated in Africa: it was first detected in Uganda in 1947 in monkeys, and later in mosquitoes. The same Aedes aegypti mosquitoes are common in South Africa in the warmer northern parts and on the Kwa-Zulu Natal coast. “They’ve been here for years, but there has never been a local case of Zika infection in the country,” says Govender. “However, our prevailing climatic conditions do seem to be favourable for the proliferation of the Zika virus, much like dengue.”
A separate Asian strain developed, and it’s this that is linked to serious infections – and 2015 outbreak in Brazil. This Asian strain has now been detected in Angola, a travel hub for the rest of Africa. And according to a report in the journal Transactions of the Royal Society of Tropical Medicine and Hygiene, “Travel data was superimposed onto season environmental suitability maps that predict the potential for subsequent Zika virus transmission. Windhoek, Maputo, Durban and Kinshasa have the greatest potential for Zika virus introduction and transmission during the summer months.”
There is now scientific consensus that Zika virus infection during pregnancy is a cause of microencephally, says Govender, citing a report in The Lancet of March this year. But while the World Health Organisation (WHO) reported two cases of the Asian strain of Zika in Angola in 2017, and more than 70 babies were born there with microcephaly between February 2017 and May this year, there are other potential causes too, such as rubella and syphilis. “Rubella can be covered for through pregnancy vaccination, and syphilis through responsible sexual practices,” Govender says.
Most people who contract the Zika virus have it so mildly they may not realise they have it. And in Brazil, the virus has now all but vanished – it’s been suggested that the high infection rate resulted in most of the population developing immunity.
Bottom line for South Africans?
Relax and carry on as normal, says Govender. But pregnant women should take care travelling abroad, especially to South and Central America and Asian countries: speak to a travel doctor. If you can’t avoid going, take precautions against mosquitoes: wear long dark clothing and closed shoes, liberally apply repellant to all exposed skin, especially ankles, and keep to places with air conditioning or fans.
And because Zika can be passed on through sexual intercourse, the Centers for Disease Control and Prevention recommend that couples with a male partner who has the virus or travelled to an area with Zika always use a condom or abstain from sex for six months.
IMAGE CREDIT: Gallo Images