Apparent contrasting rates of pharyngitis and pyoderma in regions where rheumatic heart disease is highly prevalent.

BACKGROUND: The aim of the study was to describe the epidemiology of pharyngitis and pyoderma in a Central Australian Aboriginal community with a high prevalence of rheumatic heart disease (RHD) and compare it to communities in the Top End of the Northern Territory. METHODS: Following ethics approval and community consultation, selected households were enrolled and visited over a 13-month period. People were asked if they had a sore throat and/or skin sores and asked about current or recent use of antibiotics; all throats and any pyoderma lesions were swabbed for bacterial culture. Beta-haemolytic streptococci (BHS), including group A streptococcus (GAS), were identified in the central laboratory using standard methods. Household crowding was also assessed. Results were then compared to those from the Top End study. RESULTS: Sore throat was relatively common (480 episodes per 100 person years), although there was only one case of GAS pharyngitis in 326 consultations. Only 5.5% of children <15 years had pyoderma during the course of the study. This is the opposite picture to that reported in the Top End where symptomatic pharyngitis is rare and pyoderma is common. CONCLUSIONS: Although the data are limited, the epidemiology of pharyngitis and pyoderma in this Central Australian Aboriginal community appears to be more akin to that seen in temperate climates rather than tropical Top End communities. In this community, RHD preventative measure should continue to include aggressive treatment of pharyngitis according to recommendations.

Incidence of group C human rotavirus in central Australia and sequence variation of the VP7 and VP4 genes.

Human group C rotavirus was identified in central Australia in each of eight years over a 16-year period between 1982 and 1997. Cases occurred either sporadically but over a relatively short period of time or as clustered outbreaks. These are the only reports of human group C rotavirus in Australia other than that of a single case reported approximately 1,800 km away in 1982. The electrophoretic genome profiles of isolates were identical for all those identified within the same year but different between those identified in different years. The VP7 genes of four isolates identified in four different years over a 7-year period between 1987 and 1993, and the VP4 genes of two of these isolates showed relatively little variation in genome and deduced amino acid sequence upon comparison of the equivalent genes between isolates. The sequences were also very similar to those from the corresponding genes from most of the human group C rotavirus isolates from other countries. This continues the observation of a high degree of gene sequence conservation among human group C rotaviruses worldwide.

Incidence of human astrovirus in central Australia (1995 to 1998) and comparison of deduced serotypes detected from 1981 to 1998.

The incidence of astrovirus infection was determined among infants and young children admitted to Alice Springs Hospital (central Australia) with gastroenteritis from 1995 to 1998. Astrovirus was detected by reverse transcription-PCR in 33 of 495 stool samples, and this represented 4.3% of a total of 774 stool samples tested for astrovirus, rotavirus, and Norwalk-like viruses. Astrovirus incidence was substantially lower than that of rotavirus but higher than that of Norwalk-like viruses both overall and in each of the 4 years individually. Over the period from 1981 to 1998, including the period from 1981 to 1994 during which astrovirus was identified only by electron microscopy, astrovirus serotypes (deduced from genotypes) 1, 2, 3, and 4 were identified. Deduced serotypes 1, 3, and 4 all appeared regularly over this 18-year period. Also over this period, nucleotide variation (in some cases substantial) in a section of the capsid protein precursor region of the virus genome was evident among strains of all four of the deduced central Australian serotypes. Consequent amino acid changes were, however, only evident among deduced serotype 3 strains. Geographic variation at both the genome and the resultant amino acid levels was evident among strains of all four of the deduced central Australian serotypes and their respective prototypes isolated in the United Kingdom.