Ten Massachusetts residents became infected with Zika while traveling to areas where the virus is prevalent, but no local transmission of the illness has been reported, and it’s “extremely unlikely” that will happen, a top state disease tracker told public health officials Wednesday.
The virus is spread primarily by the bites of certain species of mosquitoes, but doctors have identified a few cases of sexual transmission.
Dr. Catherine M. Brown, deputy state epidemiologist, gave a presentation on Zika at the request of the Public Health Council, an appointed board of physicians, academics, and consumer advocates that sets health policy.
Afterward, she said the state would release no information about the people who contracted Zika, including where they traveled or whether they were pregnant. The first person in the state to come down with Zika was identified in January as a Boston man.
The state public health laboratory acquired the ability to test for Zika shortly after the outbreak began in South America and now processes dozens of samples a week, Brown said.
Brown emphasized that pregnant women should avoid traveling to Zika-affected areas because the virus can cause birth defects or miscarriages. Pregnant women who travel to those areas are advised to be tested for Zika even if they have no symptoms.
Otherwise, Zika is a not a big worry: 80 percent of infected people develop no symptoms, and those who get sick typically recover in two to seven days without needing treatment. Symptoms include fever, rash, joint pain, and conjunctivitis.
Because Massachusetts already tests mosquitoes for West Nile virus and Eastern equine encephalitis, Brown said, the state is well positioned to respond to emerging viruses and the arrival of new mosquito species.
Zika is spread chiefly by the Aedes aegypti species of mosquito, which does not live in New England. Another breed, Aedes albopictus, can also transmit Zika and has occasionally been trapped in Massachusetts. The state has been keeping a close watch on a small commercial area in New Bedford, where albopictus mosquitoes have been breeding after being imported in discarded tires, Brown said.
The state stepped up surveillance for albopictus mosquitoes in 2014, before the Zika outbreak, because the species can also carry dengue and other infections, she said.Felice J. Freyer can be reached at email@example.com.