Boulder County has two confirmed cases of West Nile virus this year. The first was in Lafayette. The second came Tuesday from the county's sheriff, Joe Pelle.

He made the announcement over Facebook to let friends and family know the disease was back in Boulder County.

Pelle donates blood to Bonfils Blood Center in Boulder every six weeks. He's done that for years. But this time, he got a call from Bonfils saying there was something up with his donation.

"They said, 'Hey, um, there's an issue with your blood donation...It tested positive for West Nile disease.'" Pelle said, "I was surprised because I don't have any symptoms, I feel fine."

MORE: First Colorado mosquito tests positive for West Nile in 2017

MORE: Fort Collins blood donor tests positive for West Nile

Pelle's post about the disease was brief, but its purpose was typical of Pelle, just helping out.

"I just wanted to let people know that it's here," Pelle said. "There's been some confirmed cases and [people] need to do whatever they need to do to protect themselves and their kids."

Pelle was lucky, though. He isn't experiencing any symptoms of West Nile disease. And that's actually pretty common. Boulder County Public Health says only one in five people who contract West Nile actually experience symptoms.

"Fortunately, if you don't show any symptoms and it doesn't make you ill...there's really little to show that there's any long term consequences to that," said Marshall Lipps, an environmental health specialist with Boulder County Public Health.

And West Nile disease in Boulder County is relatively common. Lipps said Boulder, Larimer, and Weld Counties have a high incidence of West Nile compared to other states and counties in the region. Boulder County had 23 cases of West Nile disease in 2016.

The county's public health office already tests mosquito populations in the area frequently. They say the most dangerous months for West Nile disease are June through August. They recommend wearing long sleeves and pants and using repellant during these months. If you experience any symptoms including fever, extreme fatigue and body rashes, tell your doctor as soon as possible.