Arizona experiencing spike in West Nile Virus cases

An active monsoon season has brought relief from the summer heat, but Arizona officials are warning the rains have resulted in a spike of mosquito-borne illnesses.

The Maricopa County Department of Public Health is cautioning residents to take preventative measures to deter mosquitoes in announcing the first death attributed to West Nile Virus in 2021.

“We all need to do our part to protect ourselves, our family and our neighborhoods from mosquito-borne diseases,” Dr. Rebecca Sunenshine, medical director of the Disease Control Division at Maricopa County Department of Public Health, said Thursday in a statement. “With so much rain this summer, we all need to stay mindful of eliminating standing water where mosquitos can breed, like pet dishes, potted plants, and even toys.”

The department said the resident who died was a man in his 60s who had additional health issues.

The state has seen a significant increase in confirmed and probable cases of West Nile Virus in 2021 compared with 2020. The Arizona Department of Health Services reported 11 confirmed and probable cases of the virus in 2020. Through Friday this year, that number has grown to 53 confirmed and probable cases. Maricopa County is reporting 33 confirmed cases.

ADHS reports seven counties have set more than 28,000 mosquito traps since April. The traps have caught more than 6,000 Culex spp mosquito pools. That type of mosquito is known to carry West Nile Virus.

The majority of the cases are in Maricopa County, home to much of the Phoenix metropolitan area. The Maricopa County Environmental Services Department (MCESD) has seen a nearly 400% increase in positive West Nile virus mosquito samples compared with 2020.

“Public Health is working very closely with healthcare providers, Maricopa County Environmental Services and state and federal partners to maintain a strong surveillance system both for humans and mosquitoes, and to put prevention strategies in place,” Sunenshine said.

West Nile Virus is spread through the bite of a mosquito that is infected with the virus. While serious, only a fraction of those infected will show symptoms. More serious cases can develop encephalitis or meningitis. People over age 60 with other medical conditions are at higher risk for severe complications.