CDC is not releasing a list of the 22 states with confirmed and suspected cases because of privacy issues. Most of the cases have occurred in children. The symptoms tend to occur about a week after they had a fever and respiratory illness.
CDC officials say they haven't found the cause. Although the cause remains a mystery in the majority of cases, the 2014 jump coincided with "a national outbreak of severe respiratory illness among people caused by enterovirus D68", though it wasn't found in all patients, according to the CDC. Another spike came in 2016. The CDC knows of one child who died with the disorder in 2017. Officials have been baffled by the increase, and are starting to count suspected cases as well as confirmed ones to better anticipate increases in confirmed cases over the coming months. But Messonnier cautioned that it would be "premature" to be confident that this year will be the same as the earlier years.
Parents have reported that the limbs of affected children appear lifeless.
There is no specific treatment for the disorder, and long-term outcomes are unknown.
However, officials have not been able to identify the cause of most of the AFM cases, or the reason for the spikes in 2014, 2016 and now 2018. Maryland's first case was reported September 21. It's also important to note that the number of known or suspected cases is small, so the odds of contracting the illness are extremely low.
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"The most common etiology is probably a viral infection that starts off the process, and there's probably several different viruses that can cause acute flaccid myelitis", said Dr. Samuel Dominguez, medical director of the clinical microbiology laboratory at Children's Hospital Colorado. "Parents need to know that AFM is rare even with the increase in cases we are seeing now". Other symptoms may include trouble moving the eyes, drooping eyelids or facial droop and weakness.
Some patients recover quickly, while others experience paralysis and require ongoing care.
AFM may be caused by other viruses, including enterovirus, environmental toxins and a condition in which the body's immune system attacks and destroys tissue that it mistakes for foreign material, Messonnier said: "This is a mystery so far, and we haven't solved it yet, so we have to be thinking broadly".
Officials said they will be conducting additional analysis on this year's cases. "Our medical team has been reviewing vaccine records when available during this year's investigation and do not see a correlation", said CDC spokeswoman Kristen Nordlund.
That's up from 22 people who were said to have it in 2015. But so far, no pathogen has been consistently detected in the patients' spinal fluid.