#13,742
Although the number of new and suspected AFM cases continues to slow
in the most recent reporting period - a hopeful sign that we are now past this year's peak - the CDC added 7 new confirmed Acute Flaccid Myelitis cases this past week, and 9 new PUIs (patients under investigation).
While the precise cause of these polio-like outbreaks remain a mystery, a number of enteroviruses (EV-71, EV-D68, etc.) are high on the suspect list. The CDC notes, however, that most cases have tested negative for any virus.
Paralysis - while exceedingly rare - can appear days or even weeks following a suspected viral infection, which may help explain the lack of positive lab tests.It is also possible that this paralysis is due to some sort of autoimmune response to more than one virus, or even that some unknown virus - not currently picked up by testing - is at work.
Some snippets from this week's surveillance update:
AFM Investigation
What CDC has learned since 2014
- Most of the patients with AFM (more than 90%) had a mild respiratory illness or fever consistent with a viral infection before they developed AFM.
- Viral infections such as from enteroviruses are common, especially in children, and most people recover. We don’t know why a small number of people develop AFM, while most others recover. We are continuing to investigate this.
- These AFM cases are not caused by poliovirus; all the stool specimens from AFM patients that we received tested negative for poliovirus.
- We detected coxsackievirus A16, EV-A71, and EV-D68 in the spinal fluid of four of 458 confirmed cases of AFM since 2014, which points to the cause of their AFM. For all other patients, no pathogen (germ) has been detected in their spinal fluid to confirm a cause.
- Most patients had onset of AFM between August and October, with increases in AFM cases every two years since 2014. At this same time of year, many viruses commonly circulate, including enteroviruses, and will be temporally associated with AFM.
- Most AFM cases are children (over 90%) and have occurred in 46 states and DC
(SNIP)
AFM Cases in the U.S.
So far in 2018, there are 165 confirmed cases of AFM in 36 states. These 165 confirmed cases are among the total of 320 reports that CDC received of patients under investigation (PUIs). CDC and state and local health departments are still investigating some of these PUIs.
The case counts represent only those cases for which information has been sent to and confirmed by CDC.
- In 2017, CDC received information for 35 confirmed cases of AFM in 16 states.
- In 2016, CDC received information for 149 confirmed cases of AFM in 39 states and DC.
- In 2015, CDC received information for 22 confirmed cases of AFM in 17 states.
- From August to December 2014, CDC received information for 120 people confirmed cases of AFM in 34 states.
(SNIP)
Prevention
Poliovirus and West Nile virus may sometimes lead to AFM.
You can protect yourself and your children from poliovirus by getting vaccinated.
You can protect against bites from mosquitoes, which can carry West Nile virus, by using mosquito repellent, staying indoors at dusk and dawn (when bites are more common), and removing standing or stagnant water near your home (where mosquitoes can breed).
While we don’t know if it is effective in preventing AFM, washing your hands often with soap and water is one of the best ways to avoid getting sick and spreading germ to other people. Learn about when and how to wash your hands.
For more information on what CDC is doing, see our AFM Investigation page.
A few recent studies on the possible causes of AFM include:
mBio: Contemporary EV-D68 Strains Have Acquired The Ability To Infect Human Neuronal Cells
Notes from the Field: Enterovirus A71 Neurologic Disease in Children — Colorado, 2018
Eurosurveillance Review: Association Between Acute Flaccid Myelitis (AFM) & Enterovirus D68 (EV-D68)
