NOVEL RSV GENOTYPES IN SOUTH AFRICAN CHILDREN
Nusgen U1, Bunn JEG1, Hussey G3,
Isaacs-Dolly W3 Dove W2, Greensill J2,
Hart CA2
1School
of Tropical Medicine and 2Dept Microbiology, Liverpool, UK
3Dept
of Paediatrics and Child Health, Univ. of Cape Town, S Africa
Objective: To determine the
prevalence of Respiratory Syncytial Virus genotypes in children from Cape
Town during the 2000 RSV season.
Methods: Analysis by PCR of
nasopharyngeal aspirate specimens (NPA) from 350 children who presented
with a respiratory illness. All were under 2 years, and included inpatients
and outpatients. Subsequent NP and G genotyping by PCR, and sequencing of
novel G genotypes
Results: 206 NPAs were positive for
RSV. Typing for the NP gene yielded 151 NP2 and 50 NP4 genotypes. There
were a further 5 with a previously unreported NP genotype, with restriction
sites at PstI, BglII and RsaI. Typing the G gene has identified 10 novel G genotypes, 3
confirmed by sequencing. These include the most prevalent G genotype that
season (A4AFE) present in 117 children. No genotypes
corresponded to those previously reported in the literature.
Conclusion: The presence of RSV
genotypes not reported elsewhere in the world could either suggest these
are geographically localised (as reported elsewhere in Africa), or
represent the first reports of novel genotypes which could cause infection
worldwide.
The novel NP genotype reported
is particularly unusual as this gene is usually highly conserved. The PstI restriction site is usually
only associated with RSV subgroups that infect animals, and suggests either
recombination from animal isolates or a new mutation.
RSV remains an important cause
of morbidity and mortality worldwide, for which vaccination is not yet
available. The novel NP genotype, and many new G genotypes described may
have implications for vaccine development in the future.