Enterovirus

71 type of enteroviruses have been discovered. Among these are Coxsackie A viruses, Coxsackie B viruses, echoviruses and polioviruses.

Enteroviruses, unlike herpesviruses, usually leave the body after an effective immune response. However, they can cause chronic or life-threatening conditions in certain populations, such as in patients with X-linked agammaglobulinemia (XLA).

Role in Myalgic Encephalomyelitis
Enterovirus infection has been posited as a key etiological factor in Myalgic encephalomyelitis (ME). The evidence for enteroviral persistence in ME patients has been mixed, due in part to different methods of testing and types of tissue samples (for example muscle biopsies, stool samples, stomach biopsies, cerebrospinal fluid).

Some studies have found evidence of Enteroviral infection in muscle biopsies in a subset of patients while others have failed to replicate those results.

Research by John Chia and his son, Andrew Chia has looked for enteroviruses in gut biopsies. 82% of samples were positive for viral capsid protein 1 (VP1) compared to 20% of controls. Enteroviral RNA was detected in 37% of biopsy samples 4.7% of controls. They posit that a subset of Chronic Fatigue Syndrome patients have a chronic enteroviral infection.

Treatment
There are no FDA-approved treatments for enteroviruses. The drug Pleconaril has been shown to have activity against a number of enteroviruses    but has not been approved by the FDA.

Treatment usually involves supporting the immune response particularly in those with documented immune dysfunction. Dr. Chia treats his patients with enteroviral infection with Equilibrant, gammaglobulin and interferon.

Published Studies

 * In one study, enterovirus-specific RNA three standard deviations greater than controls was found in muscle biopsies of 20% of ME patients studied.
 * A Swedish study using the Fukuda criteria was unable to find evidence of any persistent enteroviral infection in fecal samples, muscle biopsies, or cerebrospinal fluid.
 * A study on brain tissue samples from a deceased ME patient found evidence of enterovirus specific genomic sequences and enteroviral protein in the patient's cerebral cortex.
 * A second postmortem tissue study found positive enterovirus PCR sequences in the muscle, heart, brain stem, and hypothalamus of a deceased ME patient.
 * A study on stomach tissue samples from CFS patients found that 82% of patients have evidence of chronic enterovirus infection of the stomach.
 * A longitudinal study found that a percentage of patients presenting to emergency care with acute enterovirus infection would go on to develop symptoms of ME and CFS and had demonstrable evidence of viral persistence.
 * A retrospective cohort study found that 31% of ME patients had elevated enteroviral IgM antibody levels. Sixteen of these patients were retested annually over three years and all showed persistently elevated Coxsackie B neutralizing antibody levels and intermittently positive enteroviral IgM, indicating the possibility of a persistent infection.