Thursday, February 21, 2008

Norovirus - The Nursing Home Nemesis

Hong Kong has been struggling with the problem of Norovirus-caused gastroenteritis in its elder care facilities, nursing homes child care centers and hospitals. In 2006, there were 269 recorded institutional outbreaks of Norovirus, affecting approximately 3,250 people.

The scope of the problem was somewhat less in 2007, but still significant. The Centre for Health Protection (CHP) reported 93 institutional outbreaks, involving 921 victims by December 21st. One subsequent outbreak, reported on December 27th, brought the year's total number of victims to 36.

The problem shows no signs of abating in the near future. In January 2008, the CHP reported three outbreaks of gastroenteritis in Hong Kong seniors' residences. The 64 victims of these outbreaks all experienced typical symptoms of Norovirus infection - diarrhea and vomitting.

While investigations are still in progress, the initial reports, issued on January 4th, January 7th, and January 9th, describe symptoms to the confirmed outbreaks of last year. A fourth outbreak, involving 25 residents and 2 staff members in another seniors' residence was announced earlier today.

This problem is not unique to Hong Kong. Institutional outbreaks of Norovirus gastroenteritis are common in many parts of the world. In the last couple of years, for example, nursing home outbreaks have sickened 176 residents and staff of a nursing home in Spain, 52 staff members and patients in a nursing home and a hospital in Austria, and 25 residents and 5 staff members of a Slovenian nursing home. Three institutions in Japan experienced an outbreak that affected a combined total of 108 individuals, including patients, staff members and outside contacts of outbreak victims.

The United States has been wrestling with Norovirus, too. In the last quarter of 2006, long term care facilities in the US reported 762 confirmed outbreaks due to this virus. This total, which included information from only 24 of the 50 states, is an understatement of the problem, since not all of the 50 states routinely tested clinical samples for Norovirus.

Prevention and control of Norovirus presents special problems in the close quarters of health care, child care, nursing home and elder care facilities. Onset of the illness is sudden, often resulting in virus-laden vomit or feces contaminating public areas. The virus is also highly contagious - a dose of just 100 particles can cause disease. And Norovirus is more resistant to freezing, heating, and many disinfectants than either bacteria or some other viruses.

Norovirus outbreaks can best be controlled by paying careful attention to personal hygiene – especially thorough hand-washing – and disinfecting all potentially-contaminated surfaces. In some situations, isolating patients suffering from gastroenteritis may be desirable.

Chlorine bleach is an effective tool for disinfecting Norovirus-contaminated surfaces. Quaternary ammonium disinfectants, commonly used in food-service areas, do NOT work. Phenol-based disinfectants can be effective, but must be used at a higher concentration than what is recommended by their manufacturers.

For more details on dealing with Norovirus, check out the web site of the Centers for Disease Control and Prevention.


  1. Sound cleaning practices need to be examined in care home facilities. I am not saying that anyone is doing anything wrong, but there is always room for improvement "in my practical view. The CDC site gives some usefull info but if you are looking at giving this virus the boot before it runs its course you need your cleaning crew running on all 8 cylendars and to be more proactive rather than reactive.

    Proper use of cleaning products as well as the use of the correct sanitizer, contact times also need to be discussed with the cleaning staff.


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