DENVER (KDVR) — West Nile virus has hospitalized more than a dozen people across Colorado, and the season is not over yet.

Data from the Colorado Department of Public Health and Environment shows 19 people were hospitalized with the virus as of Monday. Experts warn this may not be the worst of it.

“We do believe that West Nile virus is really elevated across the state right now,” said Dr. Rachel Herlihy, state epidemiologist.

West Nile virus season is in full effect here in Colorado. CDPHE data shows 36 people have recently tested positive for the illness.

West Nile can cause neurological illness

While doctors say most people who contract the illness may be asymptomatic, 19 of the people who tested positive are in the hospital battling neurological symptoms.

“We think about 80% of people may not even know they are sick,” said Dr. Daniel Pastula, chief of neuroinfectious diseases and global neurology at UCHealth. “About 20% of the time, people may get a pretty severe, flu-like illness of high fever, rashes, joint pain, muscle pain. And then about 1% of the time, this virus may impact the nervous system.”

Demographic data shows more men are fighting the illness than women in Colorado. The average age of those infected is 50, but the youngest is 7 years old.

Larimer and Weld counties have the most reported cases right now, but Herlihy warned everyone to stay vigilant.

“There are going to be some people who are more at increased risk for West Nile virus, and that tends to be people who are over the age of 60 or people who have underlying medical conditions,” Herlihy said. “But I would say that is certainly not everyone who ends up having severe illness due to West Nile virus infection, so it’s important, really, for everyone to take precautions.”

West Nile: How to prevent mosquito bites

To avoid being bitten, experts say wearing long sleeves around dusk and dawn — when the insects are active — is helpful. Also, using DEET approved by the Environmental Protection Agency will help fend them off, but there are some alternatives too.

“Chemicals such as picaridin, which is based off the pepper plant; IR3535; or even something like oil of lemon eucalyptus, which is based off the lemon eucalyptus plant,” Pastula said.

Experts say the season for West Nile virus slows after September, once temperatures start cooling, so it’s best to be proactive until then.