Jul 27, 2012 (CIDRAP News) – A preliminary genetic analysis of
enterovirus serotype 71 (EV-71) isolates from Cambodia suggests that the virus
is part of ongoing EV-71 outbreaks in Asia and is similar to those in other
countries in the region, including Vietnam.
Writing in a ProMED Mail post yesterday, Philippe Buchy, MD, PhD,
who heads the virology unit at the Pasteur Institute in Cambodia, wrote that the
lab analyzed three randomly selected isolates from patients in different parts
of Cambodia over 4 weeks.
Genetic sequencing showed that the viruses aligned with sequences
from strains isolated in Vietnam in 2011 and 2012, in Shanghai in 2011 and 2012,
and from those in other Asian countries that have been submitted to GenBank. He
added that phylogenetic analysis suggests that the EV-71 sequences from Cambodia
cluster with EV-71 genotype C4 strains recently isolated in Vietnam and are
closely related to those detected in China.
Buchy said further genetic studies continue, but it's useful to
know that the strains in Cambodia are part of an ongoing outbreak of hand, foot,
and mouth disease (HFMD) across the region, an important consideration given
that Cambodia doesn't have enough data to gauge the true case-fatality rate of
its EV-71 outbreak.
In a comment accompanying the post, ProMed moderator Craig
Pringle, PhD, a virologist and emeritus professor at the University of Warwick
in England, proposed that, based on the institute's phylogenetic findings, some
of the subgenotypes should be reclassified. This would include designating the
C4 subgenotype as a new genotype D, he said.
He said scientists await the results of further isolate analysis,
especially of genotype C4 and any possible relation to clinical severity.
In other developments, Beat Richner, MD, founder and head of
Kantha Bopha Children's Hospitals in Cambodia—where many of the country's EV-71
patients with encephalitis and severe lung complications were treated—yesterday
lashed out for the second time against the World Health Organization (WHO) for
statements it made during the outbreak.
He said the WHO statements created panic and gave the impression
that steroid treatment made some of the children's conditions worse.
In a letter posted on his Facebook page, he wrote that all 72
children treated at Kantha Bopha had encephalitis, which must be treated with
steroids to ease brain swelling. He pointed out that HFMD lesions are a symptom
that can be caused by an array of viruses and that the severely ill patients the
hospital treated didn't have the lesions.
Richner said the patients' cause of lung destruction in the last 6
hours of their lives still isn't clear.
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