Officials from Florida’s Department of Health confirmed the state’s first case in 2018 of the polio-like illness acute flaccid myelitis (AFM) on Saturday.

State health officials did not provide specifics about the case, but the case is the first confirmed case of AFM in the state for this year, adding to a growing number of cases since 2014—when the Centers for Disease Control (CDC) first began monitoring the spread of the illness, the Miami Herald reported.

The nervous system disorder is a rare illness which has many symptoms similar to polio—including sudden weakness in the arms, loss of reflexes, and loss of muscle tone—and mostly affects children between two and six years old, according to the CDC.

In addition to the muscle and limb weakness, AFM can also cause difficulty swallowing, facial drooping, and difficulty moving the eyes, health officials say.

Although the illness can present itself after a viral infection, there is no known cause and there is no treatment or vaccine to prevent the disease.

Officials confirmed 165 cases of AFM in the U.S. for 2018, according to the CDC website, and the agency has announced it would devote more resources to studying the illness due to the increase in cases.

The agency announced last month it would launch a task force dedicated to studying AFM and how it progresses.