This is a claim that I have seen on several "Did You Know?" lists so far. They all state that when a mosquito bites you, they also urinate on you at the same time
and that is what causes the area around the bite to swell, rather than the actual bite itself.
From woman's day:
While the average mosquito weighs about 2.5 milligrams, according to the AMCA, when they bite, they drink more than 5 milligrams—twice their body weight—of blood. For a 150-pound person, "that's like drinking a 300-pound milkshake," says Dr. Sirot. Once filled to the brim with blood, mosquitoes often excrete waste so they can fly away. This process, known as diuresis, happens with all species—though the type of waste product varies. Mosquitoes that can transmit malaria (anopheles) excrete plasma, while those that can transmit dengue and yellow fever (aedes) excrete urine.
- Is it true that mosquitoes urinate on the victim when they bite?
- Does the urination cause an allergic reaction leading to swelling around the bite area?