Predicting Zika Vector Seasonality

Micaela Martinez, PhD, postdoctoral fellow in the Department of Ecology and Evolutionary Biology at Princeton University, explains the statistical software that she uses in her studies to generate a calendar that shows the optimal time to get pregnant.

Interview Transcript (slightly modified for readability)

“The statistical software that I put together takes a couple bits of information. Public health officials will need to know what time of year, so what month or which weeks of the year, Zika virus transmission is at its lowest for their region. They can get this information by either looking at case reports for individuals [who] have come in with Zika infection or they can use a mosquito abundance as a proxy. Mosquitos are transmitting this virus, and if we know what time of year the mosquito population is very small, then we can assume that during that time of year the virus is not going to be transmitted very much.

If local public health officials know what time of year we anticipate to be the low season for Zika, and we also have some information about when during gestation the fetus is susceptible to birth defects or miscarriage [we would take] those two bits of information [and] plug them into the statistical software [which] will generate a calendar. This calendar is essentially the optimal time to get pregnant, so it tells you what calendar week of the year you align particular periods of gestation.

For instance, as an example, I got mosquito data from Puerto Rico, which is one of the US territories that has active Zika transmission, and there the Aedes aegypti mosquito is at its low point during about calendar week 17. If you take that, and you put it into the software, then it will tell you what time of [the] year is best to get pregnant, for [those who live in] Puerto Rico.

This should, and could, be tailored to any country [and] any region. It's really important that it’s done locally because the seasonal changes in the mosquito abundance and the seasonal changes in Zika transmission are very likely to be region-specific. So, the optimal time to get pregnant in Brazil would be very different than let’s say, [that of] somewhere like Florida, if Zika transmission remains active there.”