Evidence is piling up of a causal link between the Zika virus and both microcephaly and Guillain-Barre syndrome, according to the World Health Organization.
WHO reports show that more than 40 countries in four of the WHO's six regions have recorded Zika virus infections while only two places — Brazil and French Polynesia — have shown an increase in microcephaly cases.
The situation is particularly serious in Brazil, which has recorded more than 4,700 cases of babies born with abnormally small heads and brains.
In addition, the WHO has confirmed eight countries where the Zika virus is present and cases of Guillain-Barre syndrome have been reported.
In the case of microcephaly, valuable information is likely to emerge from some 5,000 pregnant women in Colombia who are infected with the Zika virus, Bruce Aylward, the WHO's executive director of outbreaks and health emergencies, told VOA.
The first cases occurred in October, he said, and infections are on the rise.
"Now, women who would have been exposed at that time would probably in the first trimester, [and] would probably deliver in June. So, that is obviously four or five months away,” Aylward said. “So, that is why … it could take six to nine months. … So, you are probably looking at midsummer at the longest."
Several autopsies performed on babies with microcephaly have shown the presence of the Zika virus, he said. Autopsies on people who have died of Guillain-Barre syndrome have turned up similar results.
The WHO is taking the approach of, as Aylward puts it, considering "the virus guilty until proven innocent" because of the devastating potential consequences resulting from Zika.
In the meantime, the WHO says the best way to prevent the virus from spreading is for communities to remove standing water where mosquitoes breed. The health agency urges people, especially pregnant women, to protect themselves by using insect repellent, wearing long clothes to prevent bites, sleeping under mosquito nets, and screening off doors and windows.