Expert Q&A: Zika and the Rio Olympics

Friday, 5 August 2016, 12:12 pm
Press Release: Science Media Centre

Expert Q&A: Zika and the Rio Olympics
5 August 2016

With the Rio Games about to kick off, we've asked NZ experts about Zika virus, the risks and recommended precautions.

An excerpt of the Q&A is below - journalists registered with the SMC can access the full Q&A at Scimex.org.

Register here for instant access to research and expert recommendations.

We'll update Scimex as more experts respond or if new issues arise during the Games. Feel free to use these comments in your reporting and contact the SMC if you have specific questions or stories that you'd like to talk to experts about.

Professor John Crump, McKinlay Professor of Global Health, Dunedin School of Medicine, University of Otago:
What are the symptoms of Zika infection in most people? Is it different in pregnant women?
"Most people (80%) with Zika virus infection have no symptoms and remain well. For the 20% who develop symptoms, 90% develop a rash, 65% have fever or joint pains. About half get conjunctivitis without pus (red eyes).

"Rash and fever are common symptoms of a number of other tropical infections, including dengue and chikungunya. In those unlucky enough to get ill, symptoms could last for several days and sometimes longer. Zika virus infection is not more severe in pregnant women, but they may pass the infection to their foetus leading to risk for birth defects, especially babies with small brains (called microcephaly)."

How would NZ respond if we had an increase in Zika cases in the country?

"Unlike the southern United States, New Zealand lacks the mosquito vectors required to transmit Zika virus. An increase in cases in New Zealand would most likely be due to travel to areas with active Zika virus transmission or onward sexual transmission of Zika virus.

"The New Zealand Ministry of Health has guidelines for healthcare providers for dealing with Zika virus in pregnancy. New Zealand has a registry of pregnant women with Zika virus infection, as well as enhanced surveillance for babies born with small heads to pick up potentially affected neonates and infants who were not identified earlier."

Dr José Derraik, senior research fellow, Liggins Institute, University of Auckland:

What new research is there regarding which mosquito species could potentially carry Zika? How does this relate to the mosquitoes we have in NZ and their distribution?

"The known mosquito vectors of Zika virus are Aedes aegypti and Aedes albopictus. However, recent evidence from the Oswald Cruz Foundation in Brazil has indicated that Culex quinquefasciatus may also be a vector of this virus.

"The relevance to New Zealand is that while Aedes aegypti and Aedes albopictusare not present here, Culex quinquefasciatus has been in this country since at least 1848. It is present in much of the North Island and in northern areas of the South Island.

"In addition, the ability of other Aedes species to transmit Zika virus is unknown, such as the introduced Aedes notoscriptus, which thrives in close association with humans in northern New Zealand and is a laboratory vector of other flaviviruses. Therefore, although the risk of Zika virus transmission to humans is much lower in New Zealand than in other countries, this possibility cannot be simply disregarded."

What are the recommendations for travellers - including pregnant women - going to Rio, or other countries where Zika is present?

"As it is usual for the prevention of any mosquito-borne disease, travellers should take protective measures to avoid being bitten by mosquitoes. These include using appropriate insect repellents (e.g. containing DEET), sleeping under a mosquito net, staying in areas where doors and windows have screens and using long-sleeved shirts and long pants.

"It is recommended that pregnant women simply do not travel to areas where there is ongoing transmission of Zika virus.

"For women attending the Olympic Games who plan to become pregnant, they should wait 8 weeks after their return to New Zealand before attempting pregnancy. If their partner has symptoms of Zika virus infection, this period should be extended to 6 months.

"Sexual transmission of Zika virus from male to female has been repeatedly reported, but more recently there has been a case of female to male transmission. As a result, it is advisable to use condoms during intercourse, not only while in Rio but for 8 weeks after returning to New Zealand (for 6 months in case a male partner has developed symptoms of Zika virus infection)."

What about people coming back from overseas possibly infected with Zika - should they take precautions to avoid being bitten by local mosquitoes?

"The Olympic Games are happening during the Southern Hemisphere winter. As a result, the risk of local transmission of Zika virus in New Zealand is very low, because mosquito populations in the country tend to dwindle considerably at this time of the year.

"Nonetheless, one can never be too careful, and it would be advisable to avoid being bitten by mosquitoes in New Zealand for at least 3 weeks after first developing the symptoms of Zika virus infection."

Read the full Q&A on Scimex.org

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