The number of cases of acute flaccid myelitis (AFM) reported across the USA may have topped out for the year, the CDC said.
While there's still a lot experts don't know about AFM - including, most importantly, what causes it and how best to treat it - health officials have noted distinct seasonal patterns associated with the condition. 12 states report only one confirmed case and 19 states have reported zero confirmed cases. A total of 299 possible cases had been referred to the CDC this year, as of November 30. It affects the nervous system, specifically the area of the spinal cord called gray matter, which causes the muscles and reflexes in the body to become weak. More than 400 confirmed cases, majority in children, have been reported in the past four years, and one child with AFM died last year.
Competing theories have emerged about what triggers AFM. Symptoms of this type are often the result of a viral infection; and a specific family of enterovirus-EV-D68-is a prime suspect in these cases.
Lead author and clinical fellow, Matthew Elrick, M.D., Ph.D., and his neurologist colleagues reviewed the medical records and available MRIs of patients and categorized the children as definitively having AFM or having a potential alternative diagnosis.
Without clear guidance, doctors are trying several different kinds of treatment.
Last week, the CDC said that more than 95% of the patients with AFM this year have been children younger than 18, and the average age of those infected was 5. In 2014, there were 120 confirmed cases; in 2016, there were 149 cases.
The CDC began monitoring AFM in 2014, and though the agency is still unsure what causes the disease to spread so rapidly, a pattern has developed in which more cases of AFM are confirmed every two years. Of these cases, 116 have been confirmed while 170 cases are still pending as they are under investigation. In its weekly apprised on cases of the ailment the agency said there have been 134 chronic cases in 33 states this year.