Michael Lyon

Epidemics of Gastroenteritis during 2006 Were Associated with the Spread of Norovirus GII.4 Variants 2006a and 2006b

BACKGROUND Acute gastroenteritis is commonly associated with norovirus genogroup II (GII) infection. Norovirus GII has 17 classified genotypes (GII.1-GII.17), but only 1 norovirus genotype (GII.4) is associated with global epidemics of gastroenteritis. In 2006, an increase in global norovirus activity was observed. METHODS During the period from December 2005 through August 2006, a total of 231 fecal samples were obtained from patients with acute gastroenteritis from Australia and New Zealand. Norovirus RNA was amplified and sequenced to determine norovirus genotype and relatedness to known epidemic norovirus GII.4 variants. RESULTS Two GII.4 variants, designated 2006a and 2006b, were identified in 61.8% and 11.3%, respectively, of the 186 cases investigated. Norovirus 2006a and 2006b have also been implicated as the predominant causes of norovirus-associated gastroenteritis across Europe in 2006. CONCLUSIONS The global increase in norovirus-associated gastroenteritis in 2006 was linked to the emergence of 2 novel GII.4 variants, 2006a and 2006b.

Detection of human bocavirus in respiratory, fecal, and blood samples by real-time PCR.

Human bocavirus (HBoV) has been detected worldwide in respiratory samples. Two real‐time PCR assays, targeting the non‐structural protein (NP‐1) and viral protein (VP‐1) genes, were designed and validated to detect HBoV in patients with respiratory disease, gastroenteritis, or systemic illness. Sensitivity of the NP‐1 and VP‐1 assays were equal to the conventional PCR assay previously described by Allander et al. [2005: Proc Natl Acad Sci USA 102: 12891–12896] being 100%, and giving specificity of 94% and 93%, respectively. There was no cross‐reaction identified with unrelated respiratory agents, or to human DNA. The limits of detection were 10 copies of genomic DNA equivalents per reaction for both assays. The assays were used to screen three different sample populations, combined nose, and throat swabs (n = 96) from children with acute respiratory disease, fecal samples (n = 375) from adults, and children with gastroenteritis and whole blood (n = 229) collected from 31 immunocompromised children taken over an 18‐month period. In total 17 (18%) respiratory samples and 18 (4.8%) fecal samples were identified as having HBoV present. Of the pediatric whole blood specimens investigated, HBoV was detected in six (2.6%) samples from four patients. In summary, two real‐time PCR assays targeting different genes were designed and validated for use as screening methods for the detection of HBoV. HBoV was found in three different specimen types: parent‐collected combined nose–throat swabs, fecal samples collected from symptomatic individuals and whole blood from immunocompromised children. J. Med. Virol. 81:488–493, 2009.

Identification of Strains of RotaTeq Rotavirus Vaccine in Infants With Gastroenteritis Following Routine Vaccination

BACKGROUND RotaTeq vaccine was introduced into the Australian National Immunisation Program in 2007. This study identified and characterised rotavirus strains excreted by infants who presented with symptoms of gastroenteritis following recent RotaTeq vaccination. METHODS Fecal samples (N = 61) from children who developed gastroenteritis following recent RotaTeq vaccination were forwarded to the Australian Rotavirus Surveillance Program (ARSP). RotaTeq-positive samples were genotyped and regions of the VP3, VP4, VP6, and VP7 genes were sequenced. Also, 460 rotavirus-positive ARSP routine surveillance samples were analyzed by dot-blot Northern hybridization to detect RotaTeq vaccine-derived strains circulating in the community. RESULTS Thirteen of the 61 samples collected from infants developing gastroenteritis after RotaTeq vaccination contained vaccine-derived (vd) rotavirus strains. Of these, 4 contained a vdG1P[8] strain derived by reassortment between the G1P[5] and G6P[8] parental vaccine strains. Northern hybridization analysis of 460 surveillance samples identified 3 samples that contained RotaTeq vaccine-derived strains, including 2 vdG1P[8] reassortant vaccine strains. CONCLUSIONS During replication and excretion of RotaTeq vaccine, reassortment of parental strains can occur. Shedding of RotaTeq vaccine strains in 7 of 13 infants was associated with underlying medical conditions that may have altered their immune function. The benefits of vaccination outweigh any small risk of vaccine-associated gastroenteritis.

Studies of measles viruses circulating in Australia between 1999 and 2001 reveals a new genotype

Nineteen distinct measles virus (MV) strains associated with nine different genotypes were identified in five Australian states (Victoria, New South Wales, Queensland, Northern Territory and Western Australia) between 1999 and 2001. One of the strains identified is likely to represent a new genotype within the clade D viruses (proposed to be d9). No evidence for an indigenous MV strain was found. When epidemiologic information associated with the index case was available for the outbreaks, it usually supported introduction of the virus from overseas, with the main source being South East Asia. Changes in the circulation of MV in Australia since the early 1970s were also observed. Prior to the introduction of measles vaccine, the majority of the population acquired immunity through infection with wild-type virus in early childhood. Nowadays in Australia, young adults are at most risk of infection. The age range of cases in the study period was from 1 month to 48 years, with the majority (59%) of cases from individuals aged 18-30 years.