Enterovirus 68, a common respiratory virus has transpired as a primary suspect for possibly paralyzing scores of children all over the world, researchers reported on Monday.
The virus has produced polio-like paralysis on the arms and legs in 115 children in 34 states since August. The Journal Lancet Infectious Diseases contains a research which was published on Monday that supports the possibility. However, it still remained questionable.
The University of California, San Francisco examined genetic sequences of enterovirus 68 from 25 children in Colorado and California with limb paralysis, also known acute flaccid myelitis. Scientists found that the viruses were very similar, sharing mutations that resemble those of poliovirus genome.
Using the method called molecular clock analysis, the researchers concluded that the viruses were a fresh strain of enterovirus 68, which they refer to as B1. It was estimated that B1 strain occurred about four and half years ago.
Dr. Charles Chiu, the senior writer and the subordinate professor of the study at the University of California, San Francisco says, “I don’t think it’s coincidental that it’s around the time the first cases were described”.
The study found only one child who had proof of the infection of his blood. This child was a 6-year old who was brought to Children’s Hospital Los Angeles for his complaints of difficulty in moving his left leg. The hospital chief of infectious disease, Dr. Grace M. Aldrovandi, conducted tests to check if there was enterovirus 68 in his nasal passages or stool. The boy’s blood was also examined, which was weakly positive for the infection. That is important because poliovirus may also enter the bloodstream before attacking the central nervous system.
Dr. Chiu says, “We were fortunate to detect it”. He added, “we are diagnosing these cases after the fact, when the sample you want is one taken when they start developing symptoms.” Advance sequencing was used to inspect 14 samples of spinal fluid in children with paralysis in which millions of DNA strands can be gathered and sequenced at the same time, this was done by Dr. Chiu and his associates. After the sequencing, Dr. Chiu says, “We didn’t find a virus, bacteria, fungus or parasite.”
He also stated that the B1 strain of enterovirus was found in half of the children’s nasal discharges, which was linked to their paralysis. From Nov. 24, 2013, to Oct. 11, 2014, nine out of 25 children in the study were admitted to Children’s Hospital Colorado. As early as June 2012, others were identified at Children’s Hospital Los Angeles by the Children’s Hospital Los Angeles. It was suggested that paralysis will not occur in children infected with the new strain.
A school-age girl and her younger brother were both infected with the same B1 strains of enterovirus 68 and got chills. The team found that the girl’s brother had no lifelong effects while the girl suffered paralysis in her arms and trunk. Dr. Chiu wants to develop the blood cells of the two siblings to see the difference between his and her cells.
Priya Duggal, Johns Hopkins Bloomberg School of Public Health’s genetic epidemiology program director who is not part of the study stated that Enterovirus 68 may be a funder to the children’s paralysis. “But it must not be acting alone, because children with the same virus and siblings with the same clade have different outcomes.”
Dr. Duggal conducted another study by enrolling paralytic children with their siblings to compare if there are differences in their genes.
One mother, identified under the name Marie said that her 4-year-old son could clutch something with both hands and clumsily hops after experiencing faintness in his arms and legs. His neck is crooked and his right shoulder and upper arm is weakened and limp.
Dr. Aldrovandi says “I can’t emphasize how scary this is. You have a normal child, and then all of sudden they are pretty incapacitated.”