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Mosquitoes are a vector of concern in Saint Joseph County because they can transmit diseases to humans such as West Nile Virus and Eastern Equine Encephalitis. For further information on mosquito-borne diseases.

There are 55 different mosquito species documented in Indiana.

Mosquitoes have four life stages:

  • egg
  • larva
  • pupa
  • adult

Mosquitoes need water to hatch their eggs; some species prefer shallow, stagnant water with high organic content while others prefer swamps and floodplains. Larvae and pupae are completely aquatic while adults are free-flying insects.

Adult females need blood meals from a host to produce their eggs; males do not bite. Most mosquitoes are active from dusk to dawn. Female mosquitoes find their hosts by sight, sensing carbon dioxide and body odors such as sweat.

The Indiana State Department of Health (ISDH) monitors the population and types of mosquitoes in Saint Joseph County every year. ISDH also collects samples or “pools” of mosquitoes and tests each pool for West Nile Virus. To view a current surveillance map of mosquito-borne disease in Indiana, please visit

The Saint Joseph County Department of Health does not treat for mosquitoes. The Department of Health responds to mosquito complaints that involve stagnant swimming pools or other stagnant water that could potentially be a mosquito breeding habitat.

Fogging updates 2023