How can a mosquito make you sick? The workings of a tiny vector. It weighs barely a few milligrams, flies relatively quietly, and yet is responsible for millions of illnesses each year: the mosquito.

Norovirus is an extremely contagious “vomiting bug” that spreads through food, water, and surfaces contaminated with tiny particles of vomit or fecal matter. Symptoms include diarrhea, vomiting, ...