Published Date: 1999-09-27 23:50:00
Subject: PRO> Enterovirus 71, clinical correlates
Archive Number: 19990927.1726
ENTEROVIRUS 71, CLINICAL CORRELATES
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A ProMED post
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See Also
Enterovirus 71, fatal - China (Hong Kong) (02) 990605201705Enterovirus 71 - Australia (Western) (03) 990730152336
Enterovirus 71 - Taiwan 1998: clinical signs 990821234913
Enterovirus 71 genotypes - Malaysia, Japan, Taiwan... 990821212226
Date: Fri, 24 Sep 1999
From: George A. Robertson <grobertson@bioreliance.com> & Marjorie P.
Pollack <pollackmp@mindspring.com>
Source: Media reports, 23 Sep 1999
Enterovirus 71 was the most prevalent virus in the 1998 epidemic of
enteroviruses in Taiwan, and a new study reports that it may be fatal to
children under 5 years of age. A second study showed that the virus, which
usually causes a form of meningitis, resulted in many more cases of
inflammation of the brain stem in the Taiwan outbreak. Both studies were
published in The New England Journal of Medicine [see reference below.
In the first study, researchers reviewed 129 106 cases indicative of
enterovirus 71 infection, including hand-foot-and-mouth disease and
herpangina (a viral infection in young children featuring sore throat and
headache) reported between March 27 and December 27, 1998 by the Taiwan
National Department of Health. Although a number of enteroviruses were
isolated, enterovirus 71 was identified as being more common in those
experiencing aseptic meningitis, encephalitis, pulmonary edema or
hemorrhage. Ninety-one percent of the 78 patients who died during the
epidemic were 5 years old or younger. The lead author, Dr. Monto Ho of the
National Health Research Institutes in Taipei, Taiwan concludes that
infection with the virus "may be fatal in young children.''
In the second study, a review of the same data found that the most common
neurologic complication to occur in 41 children was rhombencephalitis,
inflammation of the brainstem. The average age of the affected children was
2.5 years.
Pointing out that, historically, aseptic meningitis has been the most
prevalent neurologic condition associated with enterovirus 71 outbreaks,
lead study author Dr. Chao-Ching Huang of the National Cheng Kung
University in Tainan, Taiwan, said that this change may indicate the
reemergence of virulent strains of enterovirus 71 with serious neurologic
effects or the emergence of a new strain.
In an editorial on the epidemic, Dr. Raphael Dolin of Harvard Medical
School, Boston, Massachusetts, says it is unclear how the virus resulted in
such severe complications when in other outbreaks it has not been as
serious. In addition to speculating that there might be a new strain of
enterovirus 71, he also questions whether "host factors" special to the
children infected could have been involved. "Was the pathogenesis of the
pulmonary edema and hemorrhage related to the neurologic lesions and
associated vasomotor disturbances," Dr. Dolin asks, "...or did the
pulmonary lesions result from an immunopathologic mechanism or some other
interaction between virus and host?"
References: The New England Journal of Medicine 1999;341:929-935, 936-942,
984-985.
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ProMED
e-mail: promed@usa.healthnet.org
[The archived message "Enterovirus 71 genotypes - Malaysia, Japan,
Taiwan... 990821212226" was summarized as follows: "Enterovirus 71 (EV71),
one of the major causative agents for hand, foot and mouth disease (HFMD),
is sometimes associated with severe central nervous system diseases. In
1997, in Malaysia and Japan, and in 1998 in Taiwan, there were HFMD
epidemics involving sudden deaths among young children, and EV71 was
isolated from the HFMD patients, including the fatal cases. The nucleotide
sequences of each EV71 isolate were determined and compared by phylogenetic
analysis. EV71 strains from previously reported epidemics belonged to
genotype A-1, while those from recent epidemics could be divided into two
genotypes, A-2 and B. In Malaysia, genotype A-2 was more prevalent, while
in Japan and Taiwan, B genotype was more prevalent. Two isolates from fatal
cases in Malaysia and one isolate from a fatal case in Japan were genotype
A-2. However, all isolates from three fatal cases in Taiwan belonged to
genotype B. The severity of the HFMD did not link directly to certain
genotypes of EV71."
I do not know (or have forgotten) whether (or where, if so) the C.D.C.
genetic studies of the Malaysian isolates have been published. Someone
remind me, please? - Mod.CHC
..........................chc/es
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