New figures from Brazil show a further rise in the number of babies born with abnormally small heads to mothers infected with the Zika virus.
There have been 3,893 cases of microcephaly since October, when the authorities first noticed a surge, up from 3,500 in last week's report.
Zika is transmitted by the bite of the Aedes aegypti mosquito, which also spreads dengue and chikungunya.
Brazil is experiencing the largest known outbreak of Zika.
The Zika virus has already killed five babies in the country, said the Health Ministry. Another 44 deaths are being investigated to determine if they were caused by Zika.
Last week, Health Minister, Marcelo Castro, said a new testing kit was being developed to identify quickly the presence of either of the three viruses.
He also announced extra funds to speed the development of a vaccine for Zika "in record time".
At the moment, the only way to fight Zika is to clear standing water where mosquitoes breed.
There has been a sharp rise in the number of cases of Zika in several other Latin American countries.
CREDIT: BBC
