CHEYENNE, Wyo. (AP) — There have been fewer and fewer human cases of West Nile virus in Wyoming over the last few years.

But the Wyoming Department of Health is reminding residents not to let their guard down.

Three human West Nile virus infection cases were reported in Wyoming last year. There were 6 human cases and no deaths in 2010; 12 human cases with 1 death in 2009; 10 human cases with no deaths in 2008; and 185 human cases with 2 deaths in 2007.

Emily Thorp, of Health Department, says the agency doesn’t want people to think the low case numbers means this disease is definitely gone forever.

West Nile virus can cause potentially serious illness in humans. It is spread by mosquitoes.