Six children in Minnesota have been diagnosed with a rare "polio-like" disease since September, baffling health officials. 

The rare condition, known as acute flaccid myelitis (AFM), normally occurs as a complication following a viral infection, but can also have environmental and genetic causes, according to a statement from the Minnesota Department of Health. 

The state typically sees just one or fewer cases of AFM a year, making the six cases extremely concerning. There is no particular treatment for AFM.

Symptoms to watch out for include sudden muscle weakness, drooping facial features, neck stiffness and difficulty swallowing or speaking. 

For reasons unknown, the disease typically develops only in children. The Minnesota cases have all involved kids 10 years old or younger, health officials said. An investigation is underway to determine what caused these specific cases of AFM.

To prevent illness, the department of health recommends washing your hands frequently, staying up to date on vaccinations and avoiding mosquito bites. 

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