Communicable Diseases Report
Communicable Disease Report 30 January to 5 February 2012
In summary, we report this week period on:
- Legionnaires disease
- Meningococcal disease
- Salmonellosis
- Summary of notifiable conditions activity in NSW
For information on other communicable disease in NSW, see the A-Z of Infectious diseases and the National Notifiable Diseases Surveillance System fortnightly report for Australian data.
Note: click on the heading of each section to see a fact sheet. Updated data are provided in the links below each section.
Legionnaires disease [new]
One case of Legionella pneumophila was reported last week in an elderly woman from south east Sydney. It is unclear what the source of her exposure was but it is not likely to be associated with other previously notified cases. Since 1 December 2011, 9 cases of Legionella pneumophila have been reported. Four of these cases have been reported in 2012.
Eighty-nine cases of legionellosis were reported in 2011 (53 due to Legionella pneumophila and 28 due to Legionella longbeachae). This bacterium can cause severe pneumonia if water or dust that contains the bacteria is aerosolised and then inhaled by susceptible people. Air conditioning cooling towers associated with large buildings have sometimes been identified as the source of some outbreaks. There are requirements for building owners to register their cooling towers with local councils and there are also requirements to maintain cooling towers to minimise the growth of Legionella bacteria in the water.
Click on the link for updated Legionnaires’ disease data
Meningococcal disease [new]
One case of meningococcal disease was reported last week in a 1 year old child. This is the second case of meningococcal disease notified for 2012.
Seventy-one cases of meningococcal disease were reported with onset in 2011 in NSW. Of the reported cases in 2011, 42 cases were serogroup B and 2 were serogroup C. A free vaccine against meningococcal serogroup C disease is available for infants at 12 months of age. In NSW in 2010, 81% of cases of meningococcal disease (where serogroup was known) were caused by serogroup B, for which there is no vaccine.
Click on the link for updated meningococcal disease data, guidelines for the management of cases.
Salmonellosis
Salmonella Typhimurium outbreak associated with a restaurant
Public health staff are currently investigating a Salmonella outbreak associated with eating fried ice cream at a restaurant in Sydney. To date a total of 9 people have reported illness after eating at the restaurant with 6 of these having tested positive for Salmonella Typhimurium (MLVA 3-9-7-12-523). Two groups of people ate at the restaurant on 8 January 2012 with 7 from 8 (88%) people who consumed fried ice cream developing symptoms. A further 2 people (siblings) became unwell after dining at the same restaurant on 12 January 2012. These siblings were the only 2 of the group of 7 who consumed fried ice cream. The NSW Food Authority advised the restaurant to stop selling fried ice cream as it is considered a high risk product for infection with Salmonella.
Previous Salmonella outbreaks have been attributed to deep fried ice cream made with raw eggs. Raw eggs, like many other products, may be contaminated with Salmonella. Eggs, that are used to bind the breadcrumb coating to the ice cream, may not be cooked adequately to kill the bacteria during the brief frying process. The best way to prevent infection with Salmonella is to avoid eating raw or lightly cooked eggs, and products that contain raw eggs such as fried ice cream, hollandaise sauce, mayonnaise, tiramisu and cake batter.
There were 71 notifications of salmonellosis reported in this period. For the month of January there were a total of 371 notifications reported; this is similar to the previous five year average for January of 373 notifications. Salmonella infections tend to increase during the warmer months and peaks between January and March, though the number of notifications is often affected by large foodborne outbreaks.
Figure 1. Total monthly counts of salmonella notifications, Feb 2011 to Jan 2012 (black line), compared with each of the five previous years (coloured lines).
Figure 1. Total monthly counts of salmonella notifications, Jan 2006 to Dec 2011, compared by year.
Summary of notifiable conditions activity in NSW [update]
Table 1. NSW Notifiable Diseases activity 29 January to 5 February 2012 comparable data from January 2010
As well as the individual cases highlighted above, the following table summarises notifiable diseases activity over the last week (Table 1).
Note: cells represent the number of cases reported by public health units to the NSW Notifiable Conditions Information Management System (NCIMS) within the relevant period. Only conditions for which at least one case was recorded this week appear in the table