A team of researchers from the University of Miami have created a mathematical model to better understand the role of sexual transmission in overall Zika proliferation, according to a recent study published in Scientific Reports.
As Zika continues its march through the Western Hemisphere and as the number of infants born with microcephaly on American soil continues to increase, fears over virus transmission swirl in the public psyche.
To better understand Zika transmission, Shigui Ruan, PhD, a math professor at the University of Miami in Florida, created a mathematical model with the help of other researchers. The model is designed to establish which transmission pathways will be most important to investigate and control as Zika continues to spread.
For the model, Dr. Ruan and his team examined sexual and mosquito-borne transmission. The team collected epidemic rates from the Pan American Health Organization. They then examined the biting rates and mortality of the Aedes aegypti mosquito and rates of protection use during sexual encounters. Using equations, the team was able to estimate the number of infections resulting from each mode of transmission.
The model indicated that sexual transmission was responsible for only 3 percent of new Zika infections, but the mode also increased the overall risk of infection and prolonged the outbreak.
"Zika is a complicated virus. It's not as simple as passing a cold back and forth," said Dr. Ruan.
Sexual transmission of the virus is further complicated by the fact that Zika can live longer in semen than in blood, though a specific time table is not known. Also, most of those infected never display symptoms.
"You could conceivably have somebody who was infected, and didn't even necessarily know they were infected, carrying the disease around for a while, have some sexual encounter, and infect somebody else," said Chris Cosner, PhD, a University of Miami mathematics professor who has collaborated with Dr. Ruan on other studies. "I don't think it's been documented. But possibly, in theory, that could result in a source for an outbreak that seems to come from nowhere."
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