ARIZONA, USA — Health experts said they're noticing an increasing number of West Nile virus infections across the country and Arizona has become one of the nation's hotspots for the mosquito-borne illness.
According to the Centers for Disease Control and Prevention, Arizona has had more confirmed cases of West Nile virus than any other state in 2021.
As of Sept. 21, Arizona reported having had 97 infections this year and four virus-related deaths. Only California has reported that many virus-related fatalities so far this year.
North Dakota, South Dakota, Nebraska, and Colorado have also been identified as hotspots for West Nile virus cases.
Medical providers with the Mayo Clinic say they're observing a higher number of cases involving neuroinvasive disease, the most severe form of the West Nile infection.
"In neuroinvasive disease, the brain and surrounding tissues become inflamed, resulting in permanent brain damage and even death," said Dr. Bobbi Pritt, director of the Mayo Clinic's clinical parasitology laboratory. "Approximately 1 in 10 people with neuroinvasive disease die, and those who survive are often left with permanent disabilities."
According to CDC data, Arizona has reported 77 cases of neuroinvasive disease in 2021 -- more than any other state.
Nationwide, more than 65% of all West Nile infections in 2021 have resulted in neuroinvasive disease.
"That is significantly higher than what we usually see, in which only about 1 in 150 people with West Nile virus disease develop neuroinvasive disease," Pritt added. "However, we need to be cautious in interpreting the statistics, since many of the West Nile virus cases without brain involvement may be underdiagnosed."
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