The northeast Colorado Health Department reported Tuesday that there has been an increase of West Nile virus cases in the six-county health district.

According to the release issued Tuesday afternoon, there are two cases in Yuma County and one in Phillips County. Additional cases may be identified pending investigation.

West Nile virus is the leading cause of mosquito-borne disease in the U.S. and is spread to people by the bite of an infected mosquito. Mosquitoes that carry West Nile virus are most active in August and September, but because of the unseasonal warm weather they will continue to be active until the first few hard freezes.

There are no vaccines for humans to prevent West Nile virus and there are no specific medications to treat the disease. Fortunately, most people infected do not feel sick and few people infected develop serious symptoms. About one in five people who are infected may develop a fever and have other symptoms which can include headache, body ache, joint pain, vomiting, diarrhea, or rash.

Most people who show symptoms such as fever recover completely. For a few rare cases, however, the virus can cause a serious brain infection such as meningitis or encephalitis. These infections begin suddenly with high fever and headache and may progress to stiff neck, disorientation, tremors and coma. Severe infections can result in permanent brain damage or death.

The most effective way to avoid West Nile virus disease is to prevent mosquito bites. Following the 4 D's will protect against infection:

Dusk/Dawn - mosquitoes are most active during this time, if possible, stay indoors.

Dress - wear long-sleeved shirts and long pants to prevent mosquitos from biting.

DEET – use a repellant when outdoors, preferably with DEET as an ingredient.

Drain – remove any standing water from around your house.

If you have or think you have been exposed to West Nile virus, you should contact a medical professional as soon as possible.