In the lead up to the 2016 Rio Olympic Games let’s take a look at Zika virus…

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  • July 19, 2016

What is Zika and what are the symptoms?

Zika is caused by a flavivirus closely related to dengue and chikungunya. Only 1 in 5 people will exhibit symptoms. Zika infection can cause symptoms like fever, rash, severe headache, joint pain, muscle or bone pain. Illness from Zika is usually not severe and does not require hospitalisation. There is now strong scientific consensus that Zika infection is the cause of the majority of cases of Guillain-Barré syndrome.

How is Zika transmitted?

Transmission can occur via bite from an Aedes mosquito, a blood to blood transfer or sexual contact from an infected male via his semen. Transmission via Aedes mosquito is the most common form of transmission. The Australian Health Department has a regularly updated  list of countries  in which Zika has been confirmed.

Types of Zika transmission

The virus has been known about for some years and the risk of transmission is considered low. There have been hundreds of recorded cases of sexual transmission from male to female and 1 case of male to male in the current epidemic in Central and South America. Sexual transmission of the virus can occur through oral, vaginal or anal sex. It is not known if sexual transmission of Zika can occur from female to male and there has been no evidence of this occurring to date. There have been a number of cases of Zika virus transmission in Brazil and French Polynesia via blood transfusions.

Microcephaly and Zika

The recent epidemics in Central and South America have seen a dramatic increase the number of recorded cases of microcephaly. In the period 2001 and 2014 Brazil had on average, about 163 cases of microcephaly a year (this includes non-Zika related microcephaly). For the year 2016 Brazil has advised that the number of Zika-related microcephaly  cases is stable at 4908. For key facts about Zika virus and pregnancy click here. There is no evidence of Zika virus transmission via breast milk.

What are the Australian recommendations for pregnant women?

The Australian Health Department describes Zika as an evolving situation. Info for clinicians and public health providers can be found here. A useful tool is the interim table for the clinical assessment and screening of asymptomatic pregnant women can be found here.

Sexual contact with a confirmed Zika-positive person or person who has traveled to Zika area

Current CDC guidelines advise abstinence or use of condoms for oral, anal, vaginal sexual contact for up to 6 months after a confirmed symptomatic or asymptomatic infection and abstinence or condoms for 8 weeks post a partner returning an area where there was Zika.