Preparing the outbreak assistance laboratory network in the Netherlands for the detection of the influenza virus A(H1N1) variant.
BACKGROUND
Late April 2009, human infection with variant influenza virus A(H1N1)v emerged in the Northern Americas posing a threat that this virus may become the next pandemic influenza virus.


OBJECTIVE
To prepare laboratories for surge capacity for molecular diagnosis of patients suspected for A(H1N1)v infection in the Netherlands.


METHODS
A panel of 10 blinded specimens containing seasonal A(H1N1) or A(H3N2), or A/Netherlands/602/2009(H1N1)v influenza virus, or negative control was distributed to the outbreak assistance laboratories (OAL) together with influenza virus A (M-gene), swine influenza virus A (NP-gene) and influenza virus A(H1N1)v (H1v-gene) specific primers and probes and protocol (CDC Atlanta, USA). Laboratories were asked to implement and test this protocol.


RESULTS
All OAL were able to detect A(H1N1)v using the CDC M-gene reagents, the majority with similar sensitivity as the in-house M-gene based assays. RT-PCRs used in routine diagnostic setting in the OAL specifically designed to detect H1, H3, or NS1 from seasonal influenza A viruses, did not or at very low level cross-react with A(H1N1)v. The CDC swine NP-gene and H1v-gene RT-PCRs showed somewhat reduced sensitivity compared to the CDC and in-house M-gene RT-PCRs. In contrast, in-house developed A(H1N1)v specific H1v-gene and N1v-gene RT-PCRs showed equal sensitivity to CDC and in-house M-gene RT-PCRs.


CONCLUSIONS
The Dutch OAL are prepared for detection and specific identification of A(H1N1)v, although some level of cross-reactivity was observed with seasonal influenza viruses. Additionally, M-gene based generic influenza A virus detection is recommended to be able to detect emerging influenza A viruses in routine settings.
Meijer
Adam
A
Centre for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, The Netherlands. adam.meijer@rivm.nl
Beerens
Antoine
A
Claas
Eric
E
Hermans
Mirjam
M
de Jong
Arjan
A
Molenkamp
Richard
R
Niesters
Hubert
H
Overduin
Pieter
P
Rossen
John
J
Schuurman
Rob
R
Wolffs
Petra
P
Fouchier
Ron
R
Osterhaus
Albert
A
Schutten
Martin
M
Koopmans
Marion
M
D000818:Animals; D019411:Clinical Laboratory Techniques / Q000592:standards*; D003140:Communicable Disease Control / Q000379:methods*; D003429:Cross Reactions; D004196:Disease Outbreaks / Q000517:prevention & control*; D006302:Health Services Research; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000302:isolation & purification; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control / Q000821:virology*; D007753:Laboratories; D009426:Netherlands; D012680:Sensitivity and Specificity; D013552:Swine