(CNN) - Four additional cases of Eastern equine encephalitis, including two deaths, have been confirmed in Southwest Michigan, the Michigan Department of Health and Human Services said Tuesday.
Michigan has confirmed seven total EEE cases, including three deaths, officials said.
Typically, only 5 to 10 human EEE cases are reported every year, but about 30% of all cases result in death, according to the US Centers for Disease Control and Prevention.
In addition to the Michigan cases, two more people in Rhode Island have been diagnosed with EEE, the Rhode Island Department of Health and Rhode Island Department of Environmental Management said Tuesday.
In Massachusetts, there have been eight human EEE cases, the Massachusetts Department of Health said Friday.