Doctors have found the Zika virus in areas of the body protected from the immune system, such as seminal fluid, fetal brain tissue, and the placenta.
“Right now, we know it’s in the blood for a very limited period of time, measured in a week to at most 10 days,” explained Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “We know now, as we accumulate experience, it can be seen in the seminal fluid. We’re not exactly sure after the infection clears, where else it would be.”
He added, “These are all things that need to be carefully examined in natural history and case-control studies.”
The Centers for Disease Control (CDC) recently announced that doctors confirmed the presence of Zika virus in the tissue of infants who died from microcephaly, a rare birth defect.
“This is the strongest evidence to date that Zika is the cause of microcephaly,” explained CDC Director Tom Frieden. “Zika is new, and new diseases can be scary, particularly when they can affect the most vulnerable among us.”
Frieden stopped short of asserting that Zika causes microcephaly, a disorder in which the brain does not form properly during pregnancy or after birth and results in a small head. He said scientists need to perform more tests to confirm an actual link.
The CDC stated the disorder is typically uncommon. Following the Zika outbreak, however, Brazil has documented over 4,000 cases and is diagnosing an average of 200 cases a week. In 2015, the country tracked over 2,400 cases, compared to the 147 in 2014.
Doctors found 404 cases of microcephaly in newborns since November. They tied seventeen “to the Zika virus.” Fifteen of the 404 passed away, “with five linked to Zika.” Authorities are investigating 56 other deaths and 3,670 cases.
Reuters reported researchers in Slovenia described “a severely brain damaged fetus from a mother who was infected in Brazil” in a paper for the Emerging Infectious Diseases journal. The doctors found “high levels of Zika in the brain and some evidence that the virus had been replicating.” They concluded Zika survived “because it is an immunologically privileged site.”
Brazil, El Salvador, and Colombia have advised women against getting pregnant.
“It’s a very personal decision, but at this moment of uncertainty, if families can put off their pregnancy plans, that’s what we’re recommending,” stated Angela Rocha, the pediatric infectologist at Oswaldo Cruz Hospital in Brazil.
The Dallas County Health and Human Services (DCHHS) confirmed a person received the virus after “sexual contact with an individual with Zika.”
“Now that we know Zika virus can be transmitted through sex, this increases our awareness campaign in educating the public about protecting themselves and others,” explained Zachary Thompson, DCHHS director. “Next to abstinence, condoms are the best prevention method against any sexually-transmitted infections.”
Harvey Stern, medical director at Fairfax Cryobank, told USA Today that scientists do not “know how long the Zika virus can survive in semen, or whether the virus is present in the semen of men without symptoms.”
Last Friday, British researchers reported doctors found the Zika virus in a 68-year-old man 62 days after he contracted the virus.
U.S. officials recommended that any man coming from a Zika country use “condoms even with nonpregnant sex partners because the virus may persist in semen even after it clears the bloodstream.”
“They don’t say for how long,” said Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center in Nashville. “That’s because they don’t know. As it was with Ebola, we’re learning as we go.”
Brazilian scientists detected live Zika virus in human saliva and urine, which may indicate that a person in contact with these bodily fluids can contract the virus.
“I think we need to be careful that don’t we [sic] jump to any conclusions about transmissibility,” said Fauci. “When you find a virus or fingerprints of a virus in a body secretion, it absolutely does not mean that it is transmitted that way.”
Saliva can hold HIV, but it cannot spread the disease.
Others said the “low levels” can make it “impossible or unlikely” to transfer to another person. Substances in the saliva could also prevent transmission.
“I think it’s important to step back and emphasize that Zika is a mosquito-borne virus and the overwhelming majority of cases are spread by mosquitoes,” stated Frieden.
Aedes aegypti mosquitoes carry the disease. While primarily found in Africa, all but two nations in the Western Hemisphere have recorded populations of the mosquito species living there. (Chile and Canada are the exceptions.) They also carry dengue, yellow fever, and chikungunya. Doctors found Zika in one infant during an autopsy, and numerous mothers reported symptoms.