Australian Rotavirus Surveillance Program annual report, 2010/11

The Australian Rotavirus Surveillance Program together with collaborating laboratories Australia-wide conducts a laboratory based rotavirus surveillance program. This report describes the genotypes of rotavirus strains responsible for the hospitalisation of children with acute gastroenteritis during 1 July 2010 to 30 June 2011. This report represents the fourth year of surveillance following introduction of rotavirus vaccines into the National Immunisation Program. One thousand one hundred and twenty-seven faecal samples were referred to the centre for G and P genotype analysis using hemi-nested multiplex reverse transcription-polymerase chain reaction. Eight hundred and sixteen samples were confirmed as rotavirus positive. Of these, 551 were collected from children under 5 years of age, while 265 were from older children and adults. Genotype analysis revealed that a change in the dominant type occurred in this reporting period, such that genotype G2P[4] was the dominant type nationally, representing 51% of samples, followed by genotype G1P[8] (26.1%). Genotypes G3P[8] represented 11% of samples while G4P[8] re-emerged as an important genotype, and was identified in 6% of samples. Uncommon rotavirus G and P combinations continue to be identified, with G2P[8] and G9P[4] identified during this survey. Differences in genotype distribution based on vaccine usage continue to be evident in Australian states. This survey continues to highlight the fluctuations in rotavirus genotypes, with an annual change in dominant genotypes suggesting a more dynamic wild-type population.