SOURCES: Feb. 5, 2016 news conference with Tom Frieden, M.D., director, U.S. Centers for Disease Control and Prevention; Feb. 4, 2016, CDC statement; Feb. 3, 2016, statement, American Red Cross; Feb. 2, 2016, statement, Dallas County Health and Human Services; Feb. 1, 2016, statement, Margaret Chan, M.D., director general, World Health Organization, Geneva, Switzerland; Ashley Thomas Martino, Ph.D., assistant professor of pharmaceutical sciences, St. John's University, New York City; Associated Press
MONDAY, Feb. 8, 2016 (HealthDay News) -- The Obama administration is seeking $1.8 billion in emergency funds from Congress to combat the threat of the mosquito-borne Zika virus, the White House announced Monday.
The funding will allow an expansion of mosquito control programs, speed development of a vaccine, develop diagnostic tests and improve support for low-income pregnant women, the Associated Press reported.
In an interview on CBS Monday morning, President Obama said, "What we now know is that there appears to be some significant risk for pregnant women and women who are thinking about having a baby."
The White House move followed a World Health Organization (WHO) emergency declaration last week that the Zika virus was now a global health threat, based on the suspicion that the virus may be to blame for thousands of birth defects in Brazil in the past year.
Though a cause-and-effect link has not been proven, many public health experts fear the virus causes microcephaly, a condition in which babies are born with permanent brain damage and very small heads.
The U.S. action also followed a new advisory from the U.S. Centers for Disease Control and Prevention that pregnant women with a male sexual partner who has traveled to, or lives in, an area affected by active Zika virus transmission should refrain from sex or use condoms until the pregnancy is over.
The CDC said the precaution is in place "until we know more" about the dangers of sexual transmission of the virus.
The Feb. 4 advisory followed a report out of Texas that one confirmed case of Zika virus infection was transmitted through sex, not a mosquito bite.
Speaking at a Feb. 5 news conference, CDC director Dr. Tom Frieden said the agency is investigating Brazilian research that detected Zika virus in patients' saliva and urine. At this point, however, the CDC's guidance to pregnant women does not include anything about kissing, he said.
"We're not aware of any prior mosquito-borne disease associated with such a potentially devastating birth outcome on a scale anything like appears to be occurring with Zika in Brazil," Frieden added.
"Because this phenomenon is so new, we are quite literally discovering more about it each and every day," he said.
In the new advisory, the CDC added two new countries, Jamaica and Tonga, to its travel alert list of nations that pregnant women should avoid due to ongoing Zika virus transmission.
While the Zika epidemic first surfaced in Brazil last spring, Zika virus has since spread to 30 countries and territories in South and Central America and the Caribbean. The WHO now estimates there could be up to 4 million cases of Zika in the Americas in the next year, AP reported.
But over the weekend, a small ray of hope on that front emerged in Colombia. Although 3,177 pregnant women in the country have been diagnosed with the virus, President Juan Manuel Santos said there's no evidence Zika has caused any cases of the birth defect, according to the AP.
Meanwhile, health officials in the Dallas County Health and Human Services Department reported last week that an unidentified patient had become infected with the Zika virus after having sex with an individual who had returned from Venezuela, one of the Latin American countries where Zika is circulating.
Scientists have suspected that Zika could be transmitted sexually, and there have been scattered reports of similar occurrences in recent years.
If research proves that the virus can be spread through sex, it could complicate efforts to contain infections from the virus, which health officials have said is "spreading explosively" across South and Central America.
Ashley Thomas Martino is an assistant professor of pharmaceutical sciences at St. John's University, in New York City, who teaches infectious disease.
"We are dealing with an emerging strain of this virus. Zika is not new -- it has been around since the 1950s -- but this strain is showing that it can be transmitted from the mother to the developing fetus," he said. "So, the occurrence of sexual transmission may be new, but it's not that surprising given that we're dealing with a new strain of this virus."
Martino added that "most cases will be transmitted via mosquito, and this form of sexual transmission is likely to be a rare occurrence of infection."
The blood supply is also being monitored closely. The American Red Cross on Feb. 3 asked potential blood donors who have traveled to areas where Zika infection is active to wait 28 days before giving blood.
The chances of Zika-infected blood donations remain extremely low in the United States, Dr. Susan Stramer, vice president of scientific affairs at the American Red Cross, said in a statement
According to the White House, the CDC has reported 50 laboratory-confirmed cases among U.S. travelers from December 2015 through Feb. 5, 2016. There has so far been no transmission of the Zika virus by mosquitoes within the United States, but some Americans have returned to the U.S. with infections from affected countries in South America, Central America, the Caribbean and the Pacific Islands, the AP reported.
The Zika virus was first identified in Uganda in 1947, and until last year was not thought to pose serious health risks. In fact, approximately 80 percent of people who become infected never experience symptoms.
But the increase of cases and birth defects in Brazil in the past year -- suspected to exceed more than 4,100 -- has prompted health officials to warn pregnant women or those thinking of becoming pregnant to take precautions or consider delaying pregnancy.
For more on Zika virus, visit the U.S. Centers for Disease Control and Prevention.
To see the CDC list of sites where Zika virus is active and may pose a threat to pregnant women, click here.