The US Centers for Disease Control and Prevention recently announced that they are investigating more new cases of potential sexual transmission of the mosquito-borne disease."State public health departments are now investigating 14 new reports of possible sexual transmission of Zika virus, including several involving pregnant women," the CDC said in a statement. "In two of the new suspected sexual transmission events, Zika virus infection has been confirmed in women whose only known risk factor was sexual contact with an ill male partner who had recently traveled to an area with local Zika virus transmission; testing for the male partners is still pending."

zika virus The mosquito-borne virus, which is widespread in Brazil and has been linked to birth defects, has prompted concern among athletes and sports officials around the world as they prepare for the Olympic Games in Rio de Janeiro. REUTERS/Nacho Doce

While sexual transmission of the virus happens, it's unusual; the primary way for people to get infected is through mosquito bites."We were surprised, given the numbers actively being investigated," said CDC Deputy Director Anne Schuchat. "We were concerned enough that we thought it was important to share that information. ... We are seeing more than we expected to see." There have been approximately 90 cases reported in the U.S. of the infection that it's suspected to cause birth defects and a rare condition of temporary paralysis called Guillain Barré syndrome.