Incorrect identification of recent Asian strains of Coxsackievirus A16 as human enterovirus 71: improved primers for the specific detection of human enterovirus 71 by RT PCR.
BACKGROUND
Human enterovirus 71 has emerged as an important pathogen in the Asia Pacific region and it is important to be able to make a rapid and specific diagnosis for outbreak control. Recent Asian strains of Coxsackievirus A16 have changes in the VP1 gene which causes mispriming of widely used primers for human enterovirus 71 specific identification.


METHODS
Local strains of Coxsackievirus A16 were sequenced in the VP4 and VP1 genes and using sequence alignment tools, an improved set of primers were designed for specific identification of human enterovirus 71. These primers were evaluated against virus isolates as well as primary clinical specimens.


RESULTS
A total of 218 virus strains were tested. All 39 human enterovirus 71 isolates were positive and none of the 38 Coxsackievirus A16, 127 other enteroviruses and 14 prototype flaviviruses and adenoviruses were positive when tested with the new primers. When aliquots of primary specimens known to have yielded human enterovirus 71 were retrospectively tested, we found that within 2 months of collection of the specimens, greater than 90% were positive but that the success rate diminished rapidly to 18% after 2 years storage.


CONCLUSIONS
Our new primers will be useful in rapid diagnosis of human enterovirus 71 infection, and can also be used as a screening tool in surveillance programmes for early warning of human enterovirus 71 transmission.
Perera
David
D
Institute of Health & Community Medicine, Universiti Malaysia Sarawak, Kota Samarahan, Sarawak, 94300 Malaysia. davidperera@yahoo.com
Podin
Yuwana
Y
Akin
Winnie
W
Tan
Cheng-Siang
CS
Cardosa
Mary Jane
MJ
D044466:Asian People; D017931:DNA Primers; D004770:Enterovirus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*
D017931:DNA Primers