So they replaced a gene with a fake one into a mosquito and now it can't reproduce one virus - big deal. The real problem is not one virus, it's the mosquito itself, since it carries and favours the reproduce of several bacteria as well, par exemple Plasmodium.
Modifying genetically the vectors shouldn't be even a step to take to fight a virus. Fight to kill the vector or just fight another step of the reproducting ("life") cycle, called Vogralik's chain - The steps are:
- Infection's reservoir (mostly humans & animals)
- Way of spread (of the disease)
- Lieu of intake
- Concetration and virulency of the infection agent
- Sensitivy of the host (how immune the host is)