By Karolos Grohmann and Stephen Eisenhammer
ATHENS/RIO DE JANEIRO (Reuters) - The International Olympic Committee will issue an advisory note this week following the outbreak of the Zika virus which is spreading rapidly across South America months before the Rio de Janeiro Games in August.
IOC President Thomas Bach said on Thursday that guidelines would be sent to National Olympic Committees (NOCs) "today or tomorrow at the latest" as Rio prepares to host the world's biggest sporting event and the first Olympics on South American soil.
"We will do everything to ensure the health of the athletes and all the visitors," Bach told reporters during a visit to the Greek capital.
"We are in close contact with the World Health Organisation (WHO) as well as with the organizing committee and the Brazilian authorities."
The WHO warned on Thursday that the mosquito-borne disease, linked to birth defects in thousands of babies, was spreading "explosively" and could affect as many as four million people in the Americas.
Brazil's Health Ministry said in November that Zika is linked to a foetal deformation known as microcephaly, in which infants are born with abnormally small heads and brains.
The virus, a close cousin of dengue and chikungunya, causes rash, mild fever and red eyes. Some 80 percent of those infected typically do not have symptoms, making it difficult for pregnant women to determine if they have the virus. No vaccine or treatment is currently available.
Rio 2016 Games organizers said in a statement that the Olympics, which take place from Aug. 5-21, are during the winter months when the "dryer, cooler climate significantly reduces the presence of mosquitoes".
They added that a meeting was set to take place at the IOC's headquarters in Lausanne from Feb 1-2 for NOCs to discuss the matter.
"The Olympic and Paralympic venues will be inspected on a daily basis during the Rio 2016 Games to ensure there are no puddles of stagnant water and therefore minimize the risk of coming into contact with mosquitoes," organizers said.
"The Rio 2016 organizing committee is in regular contact with the Brazilian Ministry of Health and the Municipal Health department, which are the responsible authorities for guidance on health issues in Brazil and Rio."
Australian officials are warning athletes of child-bearing age they need to be aware of the specific risks of microcephaly in newborns and all team members are being advised to wear long sleeves around stagnant water and heavy vegetation.
The Australian team is also recommending team members in the Athletes' Village do not leave windows or doors open, and instead use the air conditioning provided.
"The health and wellbeing of all our team members is paramount, especially those females in the team of child bearing age," Australia's Chef de Mission Kitty Chiller said.
Several more teams were offering medical advice to athletes, that will be updated constantly as the Games approach and according to the development of the Zika outbreak.
A British Olympic Association spokesperson said: "As part of Team GB’s overall planning, our medical team has been liaising with specialists at the London School of Tropical Medicine, to ensure that team members are given the most up-to-date travel medicine advice, which includes information on bite prevention strategies.
"This information has already been shared with all sports and it will be continually updated prior to departure for the Olympic Games."
(Additional reporting by Jack Stubbs in Moscow, Mitch Phillips in London; Editing by Toby Davis)