Mosquito Bites
The Zika virus is one of the most feared infectious diseases of our day. The illness is usually
mild with symptoms lasting about a week, but if it occurs during a pregnancy, it often leads
to serious birth defects (e.g., microcephaly). This disease is spread primarily through bites
of Zika-infected female mosquitoes. As of right now, there is no vaccine for Zika and all
prevention techniques focus on
a) reducing the chances of mosquito bites through human behavioral measures
(e.g., travel restrictions, insect repellants, long-sleeved shirts, bed nets, etc);
b) reducing the local population of mosquitoes (e.g., use of insecticides, eliminating
breeding grounds);
c) reducing mosquitoes’ capacity to transmit Zika to humans. .
Both (b) and (c) can be accomplished by introducing into the environment some “modified
mosquitoes”. This is precisely the plan currently considered in Puerto Rico and your team
was hired to evaluate its feasibility.
In particular, the plan is to grow in the laboratory and release into the environment
mosquitoes carrying the Wolbachia bacterium. Female mosquitoes of this type (fW) are far
less likely to spread Zika. Moreover, “regular” female mosquitoes (fR) lay eggs that do not
hatch after mating with Wolbachia-carrying male mosquitoes (mW). In contrast all (fW +
mR) matings produce Wolbachia-carrying offspring. (See the diagram at
www.eliminatedengue.com/library/feature/ft/CI-Wolbachia-spread-diagram-large.jpg)
So, Puerto Rico is considering two different options:
1) Introducing only mW’s with the goal of (temporarily) reducing the overall mosquito
population