Reasonable Rascal
09-26-01, 22:14
MENINGITIS, ECHOVIRUSES 9, 13 & 30 - AUSTRALIA (NSW)
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Date: Wed 26 Sep 2001 15:45:46 +1000
From: Marcel Leroi [edited]
A Comment on the Prevalence of Echoviruses 9, 13 & 30 in NSW & the ACT
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In response to the recent articles on the newly described echovirus 13 activity in the US [see: Meningitis, echovirus 13 - USA 20010914.2219] and in Western Australia [see: Meningitis, echoviruses 13 & 30 - Australia (West.) 20010917.2247] we describe our own local experience.
The virus isolation laboratory at ICPMR, Westmead hospital, Sydney, Australia, is a reference laboratory for enteroviral typing of clinical isolates in the state of New South Wales (NSW) and the ACT. Electronic records have been kept since 1995 with data including the serotype and site of collection.
Echovirus type 13 has been rarely isolated at our laboratory, with a lone identification noted from a nasopharyngeal aspirate in 1995. Over the first 7 months of 2001 we have detected echovirus type 13 in 12 unique samples including 4 CSF isolations. The age range of patients was 4 months to 71 years, with 8 of the samples originating from subjects 1 year or less of age. Only one patient with meningitis was less than 12 months old. Unlike in the US report we have noted no geographic link between cases. This has occurred in the context of very high local non-polio enteroviral activity in 2001.
In the first 6 months some 168 non-polio enteroviral isolates have been received and typed, with echovirus type 9 being identified most frequently (32%). In comparison, our highest documented isolation rate in a calendar year (1999) was 258, although anecdotally our staff believe this is the busiest year for more than 25 years. The overall proportion of isolates originating from the CSF has been 17.5% over the last 5 years, with the highest rate noted in 1998 (27%). In the first 6 months of 2001, 40% of isolates originated from CSF samples. This is largely due to the preponderance of echovirus type 9 CSF isolation, with 39/54 (72%) samples originating from the CSF, consistent with a local outbreak.
Echovirus type 30 contributed to a lesser extent, with 8 of 11 specimens representing CSF samples. Together these viruses [echoviruses 9 and 30] have been circulating locally for some years representing 12-20% of total non-polio enteroviral activity over the last 3 years. In contrast, the average proportion of CSF samples for echoviruses 30 and 9 has been 39% and 33% respectively over the 5-year period. Given the abrupt rise in CSF isolation of echovirus type 9 despite recent circulation of this virus within the community, the possibility of a subtype epidemic is a possible explanation of recent phenomena. Viral sequencing is being considered to further explore this issue.
--
Marcel Leroi
Infectious Diseases Physician
Microbiology Registrar
Ken McPhie
Scientific Officer
Viral Isolation Laboratory
ICPMR, Department of Microbiology
Westmead Hospital
NSW, Australia
[ProMED-mail welcomes this comment from Drs Leroi and McPhie, which provides further evidence of the emergence of echovirus type 13 as a significant human pathogen, and in addition of the possible circulation of an echovirus type 9 strain with altered virulence. - Mod.CP]
*********************************************
Date: Wed 26 Sep 2001 15:45:46 +1000
From: Marcel Leroi [edited]
A Comment on the Prevalence of Echoviruses 9, 13 & 30 in NSW & the ACT
---------------------------------------------
In response to the recent articles on the newly described echovirus 13 activity in the US [see: Meningitis, echovirus 13 - USA 20010914.2219] and in Western Australia [see: Meningitis, echoviruses 13 & 30 - Australia (West.) 20010917.2247] we describe our own local experience.
The virus isolation laboratory at ICPMR, Westmead hospital, Sydney, Australia, is a reference laboratory for enteroviral typing of clinical isolates in the state of New South Wales (NSW) and the ACT. Electronic records have been kept since 1995 with data including the serotype and site of collection.
Echovirus type 13 has been rarely isolated at our laboratory, with a lone identification noted from a nasopharyngeal aspirate in 1995. Over the first 7 months of 2001 we have detected echovirus type 13 in 12 unique samples including 4 CSF isolations. The age range of patients was 4 months to 71 years, with 8 of the samples originating from subjects 1 year or less of age. Only one patient with meningitis was less than 12 months old. Unlike in the US report we have noted no geographic link between cases. This has occurred in the context of very high local non-polio enteroviral activity in 2001.
In the first 6 months some 168 non-polio enteroviral isolates have been received and typed, with echovirus type 9 being identified most frequently (32%). In comparison, our highest documented isolation rate in a calendar year (1999) was 258, although anecdotally our staff believe this is the busiest year for more than 25 years. The overall proportion of isolates originating from the CSF has been 17.5% over the last 5 years, with the highest rate noted in 1998 (27%). In the first 6 months of 2001, 40% of isolates originated from CSF samples. This is largely due to the preponderance of echovirus type 9 CSF isolation, with 39/54 (72%) samples originating from the CSF, consistent with a local outbreak.
Echovirus type 30 contributed to a lesser extent, with 8 of 11 specimens representing CSF samples. Together these viruses [echoviruses 9 and 30] have been circulating locally for some years representing 12-20% of total non-polio enteroviral activity over the last 3 years. In contrast, the average proportion of CSF samples for echoviruses 30 and 9 has been 39% and 33% respectively over the 5-year period. Given the abrupt rise in CSF isolation of echovirus type 9 despite recent circulation of this virus within the community, the possibility of a subtype epidemic is a possible explanation of recent phenomena. Viral sequencing is being considered to further explore this issue.
--
Marcel Leroi
Infectious Diseases Physician
Microbiology Registrar
Ken McPhie
Scientific Officer
Viral Isolation Laboratory
ICPMR, Department of Microbiology
Westmead Hospital
NSW, Australia
[ProMED-mail welcomes this comment from Drs Leroi and McPhie, which provides further evidence of the emergence of echovirus type 13 as a significant human pathogen, and in addition of the possible circulation of an echovirus type 9 strain with altered virulence. - Mod.CP]