Colombian President Juan Manuel Santos said Saturday that more than 3,100 pregnant women in his country were infected with the mosquito-borne Zika virus.
But Santos, speaking on national television, said there was no evidence yet definitively linking the virus to the devastating fetal developmental disorder known as microcephaly, which leaves newborns with deformed skulls and underdeveloped brains.
There is no vaccine or treatment for the virus, and scientists have not yet established a direct link between Zika and a spike in birth deformities reported in neighboring Brazil.
In his address, Santos also said U.S. medical investigators would soon arrive in his country to help probe the virus, which he said had most likely infected more than 25,600 Colombians. On Friday, Colombian officials linked Zika to the paralyzing Guillain-Barre syndrome, which authorities said had killed at least three people in the country.
Santos' address came as health officials in Brazil continued to voice strong suspicions that Zika has triggered a dramatic increase in microcephaly cases.
Brazil's Ministry of Health on Wednesday reported 4,180 cases of Zika-related microcephaly since October, while just 147 such cases were recorded there in all of 2014.
The spike has triggered worldwide alarm and warnings for pregnant women to avoid traveling to Latin American and Caribbean countries where Zika cases have been reported.
Live virus in saliva, urine
On Friday, Brazilian health officials said they had found live samples of the Zika virus in saliva and urine samples — a discovery that prompted official warnings that casual kissing "increases the risk" of infection.
However, researcher Paulo Gadelha stopped short of calling for an "anti-kissing" policy, and said colleagues were still trying to determine whether body fluids could spread Zika to new patients.
Brazil entered the alcohol-fueled Carnival season Friday, a time when people commonly kiss strangers they meet at huge street parties.
In other recent developments, the World Health Organization has advised health personnel across the globe not to accept blood donations from people who recently returned from countries affected by the Zika virus.
For its part, the United Nations has urged the Latin American countries affected by Zika to provide women, men and adolescents access to comprehensive sexual and reproductive health services, including contraception and safe abortion services.
Zika has spread to 24 countries in Latin American and the Caribbean. There have been a small number of cases reported in the United States, and experts say they expect to see small outbreaks of Zika in several states bordering the Gulf of Mexico.
However, authorities do not expect widespread U.S. outbreaks, in part because human exposure to mosquitoes is limited in the United States by the widespread use of air conditioning and window screens.