CDC says few Americans tested For Zika Virus actually infected

A small bit of good news in the fight against the Zika virus.   The Centers for Disease Control and Prevention says few of the over 4,500 U.S. residents tested for the mosquito-borne virus earlier this year have confirmed Zika virus infections.

In the first two months of 2016, just as the CDC and the World Health Organization began to sound the alarm about the fast-spreading Zika virus, more than 3,300 pregnant women in the U.S. were tested for Zika virus infections.  All were considered at increased risk of contracting Zika virus because they'd recently traveled to or lived in more than 3 dozen countries and territories where mosquitoes are spreading the virus.

A CDC report shows between early January and early March, 3,335 pregnant women were tested in the U.S.

In the women who had at least one symptom, 27 had confirmed Zika virus infection or signs of a prior similar infection.

In those with no symptoms, only 19 women were infected or showed signs of a prior infection.

This news comes just days after the CDC confirmed Zika can cause severe fetal brain defects like microcephaly, in which a baby's head is abnormally small.

So, far, the CDC says there has been no local transmission of Zika virus in the 50 U.S. states and the District of Columbia.  But, that, health officials say, is likely coming.

That's because the primary carrier of the virus, the Aedes aegypti mosquito, is already found in 30 states across the southern U.S., and a related species also know to transmit the virus is even more widespread.

The CDC has assigned hundreds of staffers to the Zika virus outbreak, trying to understand more about how the virus works, and how to protect women and their babies.

Speaking in an interview released by the CDC, Dr. Sonja Rasmussen, Director of the CDC’s Center for Public Health Information Dissemination,  said there is a lot investigators still need to learn.

“We don't know what the level of risk is for having a baby with a problem, after a mom is infected with Zika during pregnancy,” Dr. Rasmussen says.  “And those are really critical questions to answer."

But, even in pregnant women exposed, the likelihood of infection remains low.

The CDC says about 99% of asymptomatic pregnant women tested did not have Zika virus infections.

Still, because of the potential risk of birth defects, the CDC says pregnant women with a travel history to Zika-affected reasons should be tested