Acute Flaccid Myelitis

One of the most notable medical achievements of the past century in the United States has been the eradication of polio, a highly infectious viral disease that causes paralysis in young children. There have been several significant polio epidemics throughout the history of the United States, with the peak occurring in 1952, when there were 57,879 cases and 3,145 deaths reported. Jonas Salk’s vaccine, which was developed in 1954 through a trial of nearly two million children, was eventually used to vaccinate children across the United States. Through the widespread implementation of this vaccine beginning in 1955, the number of polio cases decreased rapidly until the disease was officially eliminated in 1979.

Over the course of the past four years, however, there have been a rising number of cases of a poliolike disease of unknown causes in the United States. This viral disease is known as acute flaccid myelitis, a rare but serious infection that affects the gray matter of the spinal cord and can cause severe weakening of muscles within the body. The symptoms for acute flaccid myelitis may develop after a viral infection such as adenovirus or West Nile virus; however, in some cases, there are no clear causes. From 2014 to the present, there have been 386 confirmed cases of acute flaccid myelitis in the United States. To this day, possible causes and treatments for all of these cases remain unknown.

This graph illustrates the number of cases of AFM recorded in the United States from August 2014 to August 2018.

What we know about AFM

Acute flaccid myelitis (AFM) is an extremely rare disease, and the sudden increase in the number of cases in the United States has caused public concern. While there are records of AFM cases in the past, they have yet to be compiled. The CDC is currently collaborating with various medical institutions to determine the number of cases that occurred in the United States before 2014, which was when the increase in cases was first noticed. In 2018 alone, there have been cases officially reported in 22 states, the majority of which have been seen in children, with the average age of patients being four years old. It can be difficult to diagnose a patient with AFM, as the symptoms share some similarity to neurological diseases such as transverse myelitis and Guillain-Barre syndrome, both of which also affect the nervous system. The symptoms of AFM include losing control over some reflexes and losing muscle tone in the arms and legs, facial drooping, and slurring of speech. In more severe cases, the muscles controlling the respiratory system may be affected, which can cause difficulty with breathing and ultimately be life-threatening. These symptoms share some resemblance to the more serious symptoms of poliomyelitis, or polio, which include weakness or paralysis in the arms or legs. An emergency room visit is necessary for diagnosing AFM to enable doctors to take a sample of a patient’s spinal fluid, which elucidates any signs of injury or viral infections within the spinal cord. There is still much to be discovered about AFM, and until the necessary research has been conducted, the exact mechanism of the disease will remain unknown.

What we have yet to learn

While there are no confirmed causes for AFM, it may possibly be related to a virus, environmental toxin, or genetic disorder. It is still unclear why some cases are related to previous viral infections and others are not, and it is unknown how those viral infections initiate AFM. Due to the fact that the symptoms are similar to that of polio, some have assumed that a virus may be a possible cause as well; however, no traces of it have been found in any of the confirmed AFM patients. As of now, AFM has no specified treatments other than physical and occupational therapy in order to assist patients dealing with loss of muscle control. Some researchers are also attempting to find ways to diminish the amount of inflammation in the spinal cord in order to prevent further attacks on the nervous system by the patient’s immune system. To prevent the contraction of viruses that could potentially cause AFM, certain precautions have been advised by health organizations such as the CDC, including minimizing exposure to mosquitos and staying up-to-date on available vaccinations.

New age, similar fears

The polio epidemic in the United States left a significant mark on the memories of many. Throughout the early 20th century, late summers were spent wary of swimming pools and public theaters in order to avoid catching the disease, since much about the virus remained unclear. It was later found that the disease was transmitted through contact with nasal, oral, or fecal secretions, which could all be present in public areas. However, without this concrete knowledge, the fears that children may contract this potentially deadly disease were amplified and any assumptions, however outrageous they may have been, about the causes of polio were believed as they were the only preventative measures available. Due to the prevalence and visibility of the disease in everyday life, people were spurred to action, and the necessary time and funds were dedicated to research and development of a vaccine. Once the effectiveness of the vaccine was proven, the US Public Health Service began a national immunization program, leading to a sharp decline in cases across the country. The impact that the polio epidemic has had on the history of the United States provides clarity into why the sudden increase in the number of cases of AFM has caused such alarm. The shadow of polio still looms over our society, and many fear that this may be history repeating itself. The shared fears of an unknown, rare disease affecting young children may incite anxieties; however, it may also lead to the greater dedication of time and commitment to research, allowing for us to discover more about the disease and possible treatments. AFM may not be directly related to the polio virus, but by examining the precedent of the studies and solutions developed during the polio epidemic, the medical and public health communities may be able to discover new approaches to treating AFM and be better prepared for the future.