1.   He also used to take me into the insect house, where he kept mosquitoes infected with tropical diseases.

2.   Humans usually get the disease from mosquito bites when the population of infected city birds is sufficiently large to infect enough mosquitoes.

3.   It has spread into New York state and Massachusetts in birds that have been bitten by infected mosquitoes.

4.   Several dozen U.S. travelers bring dengue back from vacation every year, fodder for infecting local mosquitos.