More time spent outside linked to higher likelihood of Zika infection

A recent study by a Northeastern University associate research scientist found that increased time spent outdoors correlated to a higher risk for Zika infection.

The researcher, Marco Ajelli, surveyed residents of the Miami-Dade area and found that while the majority of people spent less than one hour outside per day, a small group did spend much more time outside. That group had a higher risk of becoming infected with the Zika virus.

The majority of Zika infections in the United States occur outdoors, but in areas such as the tropics, most infections occur indoors. Ajelli said this means that time spent outdoors should be a consideration when creating strategies for combating the Zika virus.

“Maybe just looking at the areas with the highest density of mosquitos is not enough,” Ajelli said. “Of course, it is crucial, because you need to target interventions in those areas of the city, but you also have to take into account whether people spend time outdoors.”

Ajelli developed a computational model using his survey data and other recent information on Zika infection time and transmissibility that showed that Zika would infect few people, those who spend a lot of time outdoors but spread quickly among those populations.

Ajelli described in his paper in the journal PLOS Neglected Tropical Diseases that this is because there are fewer of these people, they have a high likelihood of being bitten and it would take a relatively small number of bites to infect the whole group.

“That means you have less time to put in place a vector control strategy,” Ajelli said. “Whatever strategy you want to implement, you have to be very quick and ready to take action, otherwise it could be too late.”