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Press Release

Call for vigilance against acute gastroenteritis associated with norovirus

21 August 2012

The Centre for Health Protection (CHP) of the Department of Health (DH) today (August 21) reminded members of the public and management of institutions to step up personal and environmental hygiene in the wake of a recent increase in acute gastroenteritis (AGE) and norovirus activities in Hong Kong.

A CHP spokesman said that a total of 122 outbreaks has been recorded (as of August 19) this year, the highest number for corresponding period since 2007.

Among the 65 institutional outbreaks with laboratory confirmation in 2012, 52 (80%) were associated with norovirus. The spokesman pointed out that norovirus associated outbreaks usually started in November till January the following year. However, an early increase in the number of norovirus associated AGE outbreaks has also been observed since July. Eight and 17 norovirus associated outbreaks were recorded in July and August (as of August 19) respectively, as compared to 0 to 2 outbreaks in preceding three months.

Various sentinel and syndromic surveillance systems have also recorded corresponding increases in AGE and diarrhoeal diseases.

In July, the predominant circulating strain of norovirus detected was GII.e. This strain has been detected in other countries a few years ago and was first detected locally since the end of 2011. The role of GII.e strains for current increased norovirus activity needs to be further studied.

"In Hong Kong, acute gastroenteritis outbreaks caused by norovirus outbreaks occur more frequently in winter months but they may occur throughout the year. Although norovirus infections are usually self-limiting, they are highly infectious and may result in large-scale outbreaks. Symptoms of infection include nausea, vomiting, diarrhoea, abdominal pain, fever and malaise. The infection can be transmitted by consumption of contaminated food, direct contact with the vomitus or excreta of infected persons and with contaminated objects through the oral route or aerosol spread with contaminated droplets of splashed vomitus," he said.

The CHP has issued letters to health-care professionals and various institutions today to alert them to the recent increase in AGE associated with norovirus and to provide health advice.

"Proper management and adequate disinfection of vomitus and faecal matter is of crucial importance in preventing and controlling the spread of the disease," the spokesman added.

To prevent the spread of acute gastroenteritis, the public should take the following precautions:

* Maintain high standards of personal, food and environmental hygiene;
* Wash hands before handling food and eating, and after going to the toilet;
* Cook all food, particularly shellfish, thoroughly before consumption;
* Refrain from work or school and seek medical advice if one is suffering from vomiting or diarrhoea; and
* Clean up vomitus appropriately by keeping other people away from the contaminated area, wearing gloves and a mask throughout the disinfection procedure and using disposable towels to wipe away all the vomitus from the periphery inward, before applying 1-to-49 diluted household bleach (by adding 1 part of household bleach containing 5.25 per cent sodium hypochlorite to 49 parts of water) to the surface and neighbouring area (within two metres from the edge of the vomitus) and washing hands thoroughly afterwards.

Members of the public can obtain more information on the prevention of acute gastroenteritis from the CHP's website ( ) or call the Central Health Education Unit hotline, 2833 0111.

21 August 2012