Viral and protozoal pathogens up to Week 32, 2010
During the first 32 weeks of 2010, 2654 reports of norovirus (NV) were received at HPS, an increase of 1632 (160%) compared to the same period in 2009 when there were 1022 reports. This large increase is due to the large number of reports in the first 12 weeks of the year.
During the first half of 2010, 274 general outbreaks of NV were reported to ObSurv, the surveillance system for all general outbreaks of infectious intestinal disease in Scotland. This is an increase of 108 (65%) compared to the first half of 2009 when 166 NV outbreaks were reported. It is however similar to the first half of 2008 during which 249 NV outbreaks were reported. Residential institutions and hospitals have been the two main locations identified in NV outbreaks in 2010, accounting for 50% and 46% of NV outbreaks respectively.
During the first 32 weeks of 2010, 1684 reports of rotavirus were received at HPS, an increase of 406 (32%) compared to the same period in 2009 when there were 1278 rotavirus reports. The number of reports in 2010 is similar to 2008 when there were 1710 reports.
To date in 2010 there have been no outbreaks of rotavirus reported to ObSurv, the last such outbreak was reported in 2007.
Increased reporting of E. coli O157 infections in 2010
During the first 32 weeks of 2010, HPS received 146 reports of E. coli O157 infections, an increase of 29 (25%) from the same period of 2009. A number of factors may have contributed to this increase.
The number and proportion of secondary and asymptomatic infections, for instance, has increased substantially. In weeks 1-32 of 2010, 26 cases (18%) were secondaries and 14 (10%) were asymptomatic, compared with 15 (13%) secondaries and 2 (2%) asymptomatic in the same period of 2009.