- The CDC says 252 cases are under investigation
- Now, 90 cases of acute flaccid myelitis have been confirmed in 27 states
- The average age of those affected is four years old and more than 90 percent of cases overall are in children aged 18 and younger
- The rare disease affects the nervous system and most resembles the polio virus
- Most children regain movement but, in some cases, they are required to be on respirators and could even die from neurological complications
- Earlier today, the parents of two children diagnosed with AFM in 2016 said their children's deaths in 2018 had not been 'counted' by the CDC
- The CDC maintains there are zero deaths linked to the 2018 outbreak, but admits 'gaps' in its tracking of cases from previous years
Another 16 children have contracted the rare polio-like disease, acute flaccid myelitis (AFM) - bringing the total number of confirmed cases this year to 109 across 29 states, the CDC has revealed.
Another 167 children are showing tell-tale symptoms of the mysterious illness which has emerged as a major public health threat every other year since 2014.
It seems to be caused by a combination of viruses but this year, the third time AFM has surged, the CDC is still struggling to identify exactly how and why it takes hold.
As such, the agency today formed a task force designed to investigate the driving forces and possible treatments of AFM, and to establish what post-AFM life looks like for sufferers.
'I want to reaffirm to parents, patients, and our Nation CDC's commitment to this serious medical condition,' said CDC Director Robert R. Redfield, MD.
'This Task Force will ensure that the full capacity of the scientific community is engaged and working together to provide important answers and solutions to actively detect, more effectively treat, and ultimately prevent AFM and its consequences.'
AFM is not new, but cases have been on the rise since 2014.
Though the condition remains very rare - affecting only one in a million people in the United States - CDC director Dr Robert Redfield, who took the job in March this year, says it is the agency's top priority.
Scientists are investigating a number of causes, including viruses, environmental toxins and genetic disorders.
In previous outbreaks, a virus called EV-D68 was implicated in the development of AFM.
'We know that EV-D68 - as well as other enteroviruses - can cause limb weakness, but we don't know what's triggering AFM in these patients,' said Dr Nancy Messonnier, director of the CDC's National Center for Immunization and Respiratory Diseases last week.
'We want to take advantage of all of [our] resources to figure out what is causing AFM.'
She said that the presence of pathogens in the spinal fluid is among the best indicators of AFM - but that doesn't mean the pathogens are the cause, per se.
'It could be one of the viruses we've detected, or it could a virus we haven't detectred, or it could be that [viruses are] kicking off another process' - such as an autoimmune disease or response - 'that is triggering AFM,' Dr Messonnier said.
It's unlikely that the disease is transmissible from human to human, and some children recover from their paralysis, though others never do.
Earlier today, the parents of two children who died of AFM earlier this year after their 2016 diagnoses told CNN they were outraged that that the CDC was not 'counting' their children's deaths.
Hours later, several reporters on the CDC telebriefing reiterated questions about deaths this year to Dr Messonnier.
'It's a gap in our understanding. We don't understand the long-term effects' but now she says the agency intends to 'follow-up with patients that have gotten [AFM] in previous years.'
The average age of those affected is four years old and more than 90 percent of cases overall are in children under 18.
The condition, caused by a viral infection, appears to start off as a common cold, before progressing to paralysis.
Ominously, data show there seems to be a spike in cases every two years, which has also left the agency baffled.
'CDC's been working very hard on this, since 2014, to try to understand causation and etiology,' Dr Redfield said in the interview, which will be aired on Tuesday.
'As we sit here today, we don't have understanding of the cause. We are, you know, continuing to strengthen our efforts, working in partnership with state and territorial health departments, and academic experts to try to figure this out.'
Symptoms often develop after a viral infection, such as enterovirus or West Nile virus, but often no clear cause is found.
Patients start off having flu-like symptoms including sneezing and coughing. This slowly turns into muscle weakness, difficulty moving the eyes and then polio-like symptoms including facial drooping and difficulty swallowing.
'If [AFM affects gray matter] lower in the spinal cord [paralysis will] be more in the legs and if it's higher up, it'll be more in the arms,' Dr Fernando Acosta, a pediatric neurologist at Cook Children's Medical Center, in Fort Worth, Texas, told Daily Mail Online in an interview last week.
'Or if it's closer to the neck, they can't move head, neck and shoulders. We had one case of that and that was just awful.'
In the most severe cases, respiratory failure can occur when the muscles that support breathing become weak.
In rare cases, AFM can cause neurological complications that could lead to death.
'It's a pretty dramatic disease; children have a sudden onset of weakness,' said Dr Messonier.