The mosquito-spread West Nile Virus has been reported in past years in Montana and this year might see more cases, according to the Department of Public Health and Human Services (DPHHS). West Nile Virus season starts in July and actually lasts until early October. Four out of five people infected with the virus will not have symptoms, but that one case could get a headache, body aches, joint pain, vomiting, diarrhea or a rash and it can be more severe. Montana has had deaths from West Nile in past years but not in the 11 reported cases last year. No vaccine exists for West Nile in humans. However, a vaccine for horses is available. Eight equine cases were reported in 2017.

The virus can infect birds. In fact, DPHHS reports that birds can be infected and then pass the infection to other mosquitoes that then bite humans. The 4 D's of West Nile Virus prevention:
DEET - Use insect repellents with DEET or picaridin.
Drain - Drain standing water to prevent mosquito breeding.
Dawn/Dusk - Mosquitoes are most active at sunrise and sunset. Stay inside or take precautions.
Dress - When possible, wear long-sleeved shirts and pants.