• In this Feb. 1, 2016 photo, a technician from the British biotec company Oxitec, inspects the pupae of genetically modified Aedes aegypti mosquitoes, a vector for transmitting the Zika virus, in Campinas, Brazil. The company said tests begun last April as part of a dengue-fighting program in the small southeastern city of Piracicaba suggested the release of the GM males reduced the wild Aedes larvae population in the target neighborhood by more than 80 percent. Brazil is in the midst of a Zika outbreak and authorities say they have also detected a spike in cases of microcephaly in newborn children, but the link between Zika and microcephaly is as yet unproven. (AP Photo/Andre Penner)

    British Olympic Association providing guidance on Zika

    LONDON (AP) — The British Olympic Association says it will provide medical guidance to athletes about the Zika virus ahead of the Olympics in Rio de Janeiro.

  • In this Jan. 27, 2016, file photo, an Aedes aegypti mosquito is photographed through a microscope at the Fiocruz institute in Recife, Pernambuco state, Brazil. The mosquito behind the Zika virus seems to operate like a heat-driven missile of disease. Scientists say the hotter it gets, the better the mosquito that carries Zika virus is at transmitting a variety of dangerous illnesses. (AP Photo/Felipe Dana, File)

    Health officials want more Zika samples, data from Brazil

    RIO DE JANEIRO (AP) — Brazil is not sharing enough samples and disease data to let researchers determine whether the Zika virus is, as feared, linked to the increased number of babies born with abnormally small heads in the South American country, U.N. and U.S. health officials say.

  • Brazil's Health Minister Marcelo Castro speaks to the press before attending the Mercosur Health Ministers summit to address the spread of Zika virus in the region, at the Mercosur building in Montevideo, Uruguay, Wednesday, Feb. 3, 2016. The ministers of 13 countries are meeting to coordinate actions to try and fight the spread of the mosquito born virus. Castro said that efforts are being made to create a vaccine against it. (AP Photo/Matilde Campodonico)

    APNewsbreak: Few Zika samples being shared by Brazil

    RIO DE JANEIRO (AP) — U.N. and U.S. health officials tell The Associated Press that Brazil has yet to share enough samples and disease data needed to answer the most worrying question about the Zika outbreak: whether the virus is actually responsible for the increase in the number of babies born with abnormally small heads in Brazil.