Mosquitoes are already out in droves across Montana, but they will get even worse by late July. That’s when communicable disease epidemiologist Joel Merriman says mosquitoes are expected to start spreading West Nile Virus.

"The disease ranges anywhere from West Nile Fever, which can be a fever ranging from mild to real high,"  Some people have rashes and joint pain, and then a very small percentage, 1 or 2 percent, develop a neuro-invasive disease that effects their central nervous system and can cause encephalitis (swealling of the brain) or meningitis (swelling of the meninges around the brain), which can also result in death."

Merriman says the public should follow the Five ‘D’s in order to help prevent the spread of West Nile Virus:

"Be careful during Dawn and Dusk when mosquitoes are feeding the most. Dress appropriately and wear long sleeves and long pants. Use Deet or another EPA registered insect repellent, and Drain any standing water around your home."

Although the effects of West Nile virus can be severe, about 80 percent of the people who get it never show symptoms.

The number of West Nile Fever cases can vary wildly. In 2007 alone, Montana had 202 cases of West Nile Fever, then between 2007 and 2013 the number of cases dropped down to about six per year.