DENVER -- At least 28 people in Colorado have tested positive for West Nile virus, according to the latest report from the state Health Department.

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The sharp increase in cases was attributed to a wet spring, dry beginning of the summer and wet weather again, which increased the number of mosquitoes that carry the virus.

The executive director of the Health Department, Douglas H. Benevento, said that 13 additional human cases were confirmed in Colorado over the last two days and that 10 additional cases have tested positive and are awaiting confirmation. With the five human cases already confirmed and reported, the number jumped to 28 -- the highest number of human West Nile virus cases in the country.

"We are seeing the same pattern in Colorado as seen in several Midwestern states last year, with more virus activity in mosquitoes, birds, horses," said Benevento. "Our current experience is not unexpected given that this is Colorado's second year of West Nile virus and that we have a spring and summer than have been particularly favorable for mosquitoes."

Larimer County Woman Paralyzed By Virus

The Larimer County Health Department said Wednesday that two women, both of them in their 60s, have been hospitalized with West Nile virus.

A 61-year-old woman who became ill in late July is hospitalized at Poudre Valley Hospital, suffering from paralysis of the lower legs.

A 62-year-old woman from Loveland is being treated at the same hospital for encephalitis. She became ill in mid-July.

"It is likely that this is just the tip of the iceberg of West Nile virus infections in the county as human cases are occurring much earlier this year and we have found a large number of birds that tested positive for the virus," said Dr. Adrienne LeBailly, director of the Larimer County Health Department. "We believe that infected mosquitoes are present in the lower elevations of the county. So far, we have not found any positive birds in the mountainous areas of the county, such as Estes Park."

The department is also monitoring a large number of people who are contacting their doctors and calling the state health department reporting a variety of symptoms including fever, fatigue, muscle aches, headaches, rashes, and occasionally nausea and vomiting.

"While these may be suggestive of West Nile infections, this pattern of symptoms may also indicate a number of other viral infections that are common at this time of year, such as enteroviruses. Until test results are available, we can't say that these are West Nile virus (cases)," LeBailly said.

The Larimer County Health Department has sent advisories to physicians in Larimer County and is asking that doctors' offices report the numbers of such cases seen in their offices.

Colorado reported 14 cases last year -- none fatal.

Coloradoans, especially those over 50 years old, are being reminded to take precautions by protecting themselves against mosquitoes and by reducing mosquito breeding grounds near their homes.

Such prevention measures include avoiding outdoor activities at dusk and dawn when mosquitoes are most active; wearing long-sleeved shirts, pants, shoes and socks; using mosquito repellents with DEET; and eliminating standing water in tires, birdbaths or similar water-holding containers because these may serve as mosquito breeding sites.

More information on the West Nile virus can be found at FightTheBiteColorado.com or by calling the Colorado Health Education Line at 877-462-2911.