By NewsDesk  @infectiousdiseasenews

In an Centers for Disease Control and Prevention (CDC) update Tuesday, the number of human West Nile virus (WNV) cases is now 76 in 16 states. Four fatalities have been reported.

Maricopa County/ David Benbennick

Of this total, 57 (42 neuroinvasive and 15 non-neuroinvasive) cases, or 75 percent of the cases in the country have been reported from Arizona. In fact, all 57 cases were reported from Maricopa County.

This compares with 24 total cases in all of 2018.

The remaining 15 states seen cases in the single digits.

West Nile virus (WNV) is a disease caused by a virus that is spread through mosquito bites. WNV is found on every continent except Antarctica. It was first detected in North America in 1999, and has since spread across the continental United States and Canada and is well established.

In fact, WNV is the most common mosquito-borne illness in the country.

WNV is spread to people primarily through the bite of infected Culex species mosquitoes.

Fortunately, most people infected with WNV do not feel sick. About 1 in 5 people who are infected develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness.

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