Echovirus 9: a prominent enterovirus causing CNS disease in Kuwait

Abstract number: o62

Dalwai  A., Ahmad  S., Pacsa  A., Al-Nakib  W.

Objectives: 

Enteroviruses in general are recognized as the major cause of aseptic meningitis particularly in children; however, they appear to vary in their neurotropism and neurovirulence. Some types may be overrepresented as etiological agents of CNS disease than others. The aim of this study was to genotype the prevalent enteroviruses causing CNS disease in Kuwait and to study the association between a particular enterovirus with the severity of the disease.

Methods: 

Detection of enteroviral RNA was based on semi-nested RT-PCR amplification of a portion of the 5'UTR of the enteroviral genome followed by Southern hybridization with an enterovirus specific probe to confirm the results. The enterovirus was genotyped by sequencing of the 5'UTR and the VP4 encoding region, and the sequence was analysed by BLAST analysis, CLUSTALW alignment and PHYLIP phylogenetic analysis package.

Results: 

Enteroviral RNA was detected in the CSF of 26% (168/647) of the CNS disease cases with a majority of the enterovirus positive cases (82%; 138/168) being children less than 12 years of age. Of the 8 different enteroviruses identified, echovirus 9 was the most common (45%; 66 of 147 genotyped), followed by echovirus 11 (18%; 27/147), coxsackievirus A7 (17%; 25/147) and coxsackievirus B5 (10%; 14/147). In the severe CNS disease cases (encephalitis and those cases presenting with febrile convulsions/seizures), the occurrence of echovirus 9 was significantly higher (68%; 24 of 35 genotyped) than that observed in less severe CNS disease cases presenting with aseptic meningitis (37%; 42 of 112 genotyped). Echovirus 11 and coxsackievirus B5, on the other hand were more frequent in less severe CNS disease than in severe CNS disease cases.

Conclusions: 

Echovirus 9 was found to be the predominant enterovirus associated with CNS disease in Kuwait and data obtained through this study suggests that infection with echovirus 9 may lead to a more severe CNS disease outcome. Supported by Research Administration project grants MI 04/01, YM 03/02 and College of Graduate Studies, Kuwait University.