Zika not a threat to South African population

From left to right: Prof Wolfgang Preiser and Dr Jantjie Taljaard from the Centre for Infectious Disease (CID) at the Faculty of Medicine and Health Sciences (FMHS) at Stellenbosch University; (in front) Prof Lucille Blumberg from the National Institute for Communicable Disease (NICD) and FMHS; Prof Jean Nachega from the CID at the FMHS and Dr Mike Urban from the Division of Molecular Biology and Human Genetics at the FMHS
There is a very limited possibility that South Africa will experience an outbreak of Zika fever similar to the one seen in Brazil.

This viral infection is transmitted by a variety of the Aedes aegypti mosquito that is not endemic to South Africa, explained Prof Lucille Blumberg from the National Institute for Communicable Disease at a Zika Symposium recently held at the Faculty of Medicine and Health Sciences (FMHS), Stellenbosch University.

"The Aedes aegypti mosquitos found in some regions of the country prefer outdoor areas and do not have an appetite for human blood," said Blumberg, who is also an extraordinary professor at the FMHS Centre for Infectious Diseases (CID).

Zika fever causes flu-like symptoms and is not considered to be particularly dangerous to the person infected, however it is believed to cause birth defect in babies whose mothers had Zika fever during pregnancy, explained Dr Jantjie Taljaard who heads the Division of Infectious Diseases at the FMHS.

"In four out of five cases Zika infection does not present any symptoms, but the minority of people who do have symptoms may develop a mild fever, skin rash, joint and muscle pain, headache or other non-specific symptoms that clear up within a few days," said Taljaard.

Although Zika-infection is usually not life threatening, it is thought to hold serious complication for babies whose mothers are infected during pregnancy.

"Although not yet confirmed, evidence is growing that Zika causes microcephaly – a condition whereby a child has a significant reduced head circumference compared to children of the same sex and age," Dr Mike Urban from the Division of Microbiology and Human Genetics at the FMHS explained.  "Children with this condition have a high chance of intellectual disability."

Microcephaly normally occurs in one or two children out of every 10 000, but in parts of Brazil experiencing Zika outbreaks the rate of microcephaly has increased to 20 cases per 10 000 children, he said.

According to Prof Wolfgang Preiser, head of the FMHS' Division of Virology, once a person had been infected by the Zika virus they become immune.

"We believe that the outbreak in Brazil was so severe because this area was previously unaffected by the disease and therefore the population had no immunity against it," said Preiser.

Zika was first detect in a macaque monkey in Uganda's Ziika forest in 1947 and first identified in humans five years later. Since then the virus has been detected in several African and Asian countries. In 2007 it was for the first time identified on Yap Island in Micronesia, progressing to Tahiti in French Polynesia in 2013 and reaching New Caledonia and the Cook Islands in 2014  and Easter Island in 2015. Also in 2015 it reached the South American mainland, starting with Brazil.
Wilma Stassen