Tuesday, February 28, 2017

Polio-like virus causing paralysis in over 200 children

Scientists at UCSF, University of Colorado School of Medicine, and the California Department of Public Health have been trying to identify the culprit of a paralyzing virus that has affected more than 200 children since 2014, including many Bay Area children. In humans, the course of the illness began with a flu-like syndrome followed by paralysis in one or more limbs that resulted in permanent damage. In 2014, 120 cases were found in 34 states. Only 21 cases occurred in 2015, which is apparently on par with the national average. However, in 2016, 132 cases of sudden paralysis were reported in 37 states. This points to a cyclical nature in the virus’ life cycle, which we’ve encountered for many viruses in this course.

Scientists suspected that the culprit virus would be an enterovirus since the symptoms resembled poliomyelitis. A few children tested positive for Enterovirus D68, but the association with the disease appeared to be weak. However, Enterovirus D68 has been increasing in prevalence in the United States, which has renewed interest in investigating the virus.

It had been discovered that the virus had been mutating since the 1960s that have resulted in an increase in virulence and possibility of causing paralysis. Lab mice exposed to the new strains Enterovirus D68 developed paralysis in at least one limb a few days later. Exposure to the old strains of Enterovirus D68 did not produce the same result. Autopsy of the exposed mice showed that the virus was located in the cells of the spinal cord that control the paralyzed limbs. This provides a possible explanation for why the virus couldn’t be isolated in most of the children’s spinal fluid. Perhaps if spinal cord biopsies were taken, the virus could have been isolated sooner. However, spinal cord biopsies are extremely risky.

A promising finding from these studies is that mice given antibodies from exposed mice appeared to be protected from the virus, which points to the possibility of developing a vaccine.


Read more here: http://www.sfchronicle.com/health/article/Science-closing-in-on-polio-like-virus-that-10961180.php

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