West Nile virus neurologic disease in humans, South Africa, September 2008-may 2009

Abstract

We investigated West Nile virus (WNV) as a possible disease etiology in persons hospitalized in South Africa. Of 206 specimens tested, 36 had WNV neutralizing antibodies, significantly more than in similar earlier serosurveys. Seven probable acute WNV cases were identified, suggesting WNV may be overlooked as an etiology of severe disease in South Africa.

Figure

Maximum-likelihood tree of an ≈200-bp fragment of the nonstructural 5 gene of a reverse transcription PCR–positive West Nile virus (WNV) specimen SAH5238/08 (GenBank accession no. JX974605; black diamond) isolated from a human in South Africa in 2008. The tree shows the relationship of the strain to representative sequences of 5 WNV lineages, including 5 WNV lineage 2 strains isolated from horses in South Africa in 2008 (15). The scale bar indicates nucleotide substitutions per site. Bootstrap statistics of >70% are indicated on the tree branches. WNV strains (accession numbers): B956 (AY532665), SA381/00 (EF429199), SA93/01 (EF429198), SPU116/89 (EF429197), Goshawk-Hungary/04 (DQ116961), H442 (EF429200), Sarafend (AY688948), Madagascar AnMg798 (DQ176636), HS123/08 (FJ464376), HS101/08 (FJ464378), SAE126/08 (FJ464379), SAE134/08 (FJ464380), HS125/08 (FJ464377), Rabensburg97103 (AY765264), LEIV-Krnd88-190 (AY277251), Kunjin (D00246), Egypt101 (AF260968), EthAn4766 (AY603654), Italy1998 (AF404757), Goose-Hungary/03 (DQ118127), NY385-99 (EF571854), TX2002 (DQ164205), Mexico2003 (AY660002), IND804994 (DQ256376), Japanese encephalitis ( HM228921).