Those who are infected are also advised to stay indoors and remain as isolated as possible for at least a week after symptoms first present. While the risk of a domestic outbreak is probably low, Dr. St. John said, the more exposure a Zika virus–infected individual has to the outside world, the more likely he or she is to be bitten by another mosquito, which can then carry and transmit the virus to another person.
“Chikungunya and dengue virus, which are transmitted by the same vectors [as Zika virus], have not managed to establish ongoing transmission in the U.S., despite repeated importations, [so] it is likely that Zika virus’ spread would follow a similar pattern,” Dr. St. John noted.
Though rare, sexual transmission of Zika virus has also been found in at least one case, although it had been previously suspected for some time. In December 2013, a 44-year-old Tahitian man sought treatment for hematospermia. Analysis of his sperm, however, found Zika virus, indicating possible sexual transmission of the virus.
“The observation that [Zika virus] RNA was detectable in urine after viremia clearance in blood suggests that, as found for [dengue] and [West Nile virus] infections, urine samples can yield evidence of [Zika virus] for late diagnosis, but more investigation is needed,” the study concluded.
“The best way to control all this is to control the mosquito,” said Dr. Senanayake. “You get a four-for-one deal; not only do you get rid of Zika virus, but also chikungunya, dengue, and yellow fever.” Dr. Senanayake added that advanced research is currently underway in mosquito-control efforts, including the idea of releasing mosquitoes into the wild which have been genetically modified so they can’t breed.
Now that the Illinois Department of Health has confirmed two new cases of Zika virus infection in that state, with other new cases cropping up in Saint Martin and Guadeloupe and El Salvador, providers should remain vigilant, taking note of patients who have traveled to afflicted regions and show mosquito bites. Person-to-person transmission is “rare as hen’s teeth,” said Dr. Senanayake, which is to say, it is highly unlikely to occur. Nonetheless, he said information and communication is the best way to ensure that Zika virus does not spread widely in the United States.
*This story was updated 1/25/2016.