This year, more than half of all USA states have had confirmed or possible cases of acute flaccid myelitis, the polio-like illness that can cause paralysis and mostly affects children, according to an exclusive CNN analysis.
The federal Centers for Disease Control and Prevention is investigating 127 cases of possible AFM, including 62 that have been confirmed in 22 states this year.
Maryland health officials said their first case was reported to them September 21. And though enteroviruses have been detected in some paralysis cases, it hasn't been found in others, CDC officials say. It mostly afflicts children and young adults and can be caused by toxins in one's environment, genetic disorders or viruses such as poliovirus, West Nile virus or adenovirus. Despite extensive laboratory and other testing, CDC has not been able to find the cause for the majority of the cases.
Symptoms can include sudden limb weakness, loss of muscle tone and reflexes, facial and eyelid drooping, difficulty moving the eyes, difficulty swallowing, slurred speech and, in the most severe cases, difficulty breathing, according to the CDC. CDC officials added that while they have not seen any geographical clustering, they have seen seasonal clustering, with most cases occurring in the late summer and fall, dating back to when the CDC first noticed an uptick in the illness in 2014.
Carlos Pardo-Villamizar, a neurologist and director of the Johns Hopkins Transverse Myelitis Center, said that the mystery lies in whether the damage seen in AFM is caused by an external agent or the body's own defenses. 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. What happens to patients down the line is unclear; some recover quickly, while others may need long-term care. In 2016, 22 across 17 states in 2015 and 120 across 34 states in 2014.
This year's numbers are similar to 2016 and 2014.
"What we have been told is that he's the best case scenario of a hard situation", she said.
Although symptoms resemble polio, no evidence of poliovirus has been found in specimens from any case diagnosed so far, Messonnier said. "As a parent myself, I understand what it's like to be scared for your child", she said. Health officials are alarmed and frustrated, because a specific cause hasn't been identified.
She recommended that parents take routine protections against viral infections, such as keeping up to date on immunizations, washing hands, and avoiding mosquito bites. It's a rare disease, but the CDC thought that they might glean more about the nature of the outbreak, as well as clues about how to contain it, by releasing a report to the public.
CNN reached out to health departments in every state; 48 states responded, plus the District of Columbia.