The Michigan Department of Health and Human Services confirmed the state’s first human cases of West Nile virus for 2017 on Thursday.
Four cases of WNV have been confirmed; two residents of Montcalm County, and one each from Oakland and Macomb Counties. Their illness onsets range from August 6-11, and all have been hospitalized with neurologic disease.
“This is an important reminder to stay vigilant and protect against mosquito bites throughout the summer and into the fall,” said Dr. Eden Wells, Chief Medical Executive at the MDHHS.
“All residents should take steps to prevent bites, such as use repellent and take extra care during peak mosquito-biting hours between dusk and dawn.”
Surveillance for mosquito-borne diseases is being conducted by the MDHHS and Departments of Natural Resources and Agriculture and Rural Development (MDARD).
In 2017, WNV activity appears to be widespread statewide in Michigan. In addition to the four human cases, five Michigan blood donors have had WNV detected in their blood.
To date, 148 birds have tested positive for WNV from 44 of Michigan’s 83 counties.
In addition, 86 WNV positive mosquito pools have been detected in seven Michigan counties.
Finding infected birds, mosquitoes and horses in a community is an indication of risk for human infection.
Most people who become infected with WNV will not develop any symptoms of illness. However, some become sick three to 15 days after exposure.
About one-in-five infected persons will have mild illness with fever, and about one in 150 infected people will become severely ill.
People 50 and older are more susceptible to severe WNV disease symptoms.