Report No. 022-12

TO: Chair and Members of the Board of Health
FROM: Graham L. Pollett, MD, FRCPC, Medical Officer of Health
DATE: 2012 February 16

Institutional Outbreaks in Middlesex-London September 2011 to January 2012

Recommendation

It is recommended that Report No. 022-12 re Institutional Outbreaks in Middlesex-London – September 2011 to January 2012 be received for information.

Background

Under the Health Protection and Promotion Act, institutional premises, including child care facilities, long term care and retirement homes, and hospitals, must report respiratory outbreaks (caused by influenza or other viruses) and enteric outbreaks (caused by viruses or bacteria that cause diarrhea and/or vomiting) to the Health Unit. These reports trigger a response from Health Unit to help the institution to contain and control the spread of the outbreak. As well, these reports help with monitoring communicable disease activity in the community. This report provides an overview of the 2011-2012 outbreak season to date, and reviews the role of Health Unit staff in assisting with the management of these outbreaks. As well, a description of the weekly influenza surveillance report is provided.

2011-2012 Outbreak Season

From September 1, 2011 to January 31, 2012, 61 facility-related outbreaks were reported to the Health Unit (27 respiratory and 34 enteric). Respiratory outbreaks were more prominent in the fall while enteric outbreaks became more common through the winter (Appendix A). By comparison, over the same time period in the 2010-2011 outbreak season, 82 facility-related outbreaks (49 respiratory, 30 enteric, and three combined respiratory/enteric) were reported to the Health Unit.  

A virus that was potentially causing the outbreak was identified in over half (36/61) of outbreaks reported from September 1, 2011 to January 31, 2012. Norovirus was the most frequently identified virus in enteric outbreaks while rhinovirus was the most frequently identified virus in respiratory outbreaks. Other respiratory viruses identified include parainfluenza, respiratory syncytial virus (RSV), and coronavirus. Influenza was not identified in any outbreak during this time period, in stark contrast to last season when 19 facility-related influenza outbreaks were reported to the Health Unit.

Health Unit Response to Outbreaks

Outbreak reporting by institutional premises triggers a response from Health Unit staff that is aimed at supporting the facility to limit transmission of the disease to non-infected individuals. Information is gathered about the number of ill people and their presenting signs and symptoms. This information is used to inform subsequent decisions about appropriate infection prevention and control measures to contain the outbreak. These measures may include:

• implementing precautions to protect workers from becoming ill and/or spreading the illness to other individuals under their care. These precautions might include wearing a mask, goggles, gown, and gloves when caring for people;
• excluding ill staff from the premise and limiting visitor numbers;
• keeping ill residents/patients in their rooms;
• screening people (for example, staff, visitors, new patients/residents) for symptoms;
• limiting opportunities for spread within the home by curtailing activities;
• increasing the frequency with which shared surfaces are cleaned and/or changing the type of cleaner/disinfectant that is used;
• offering immunization as well as antiviral treatment and  prevention in the case of influenza outbreaks.

Facility staff members are offered the opportunity to connect with Health Unit personnel face to face at Outbreak Management Team meetings where information can be shared, development of a plan of action can be discussed and eventually evaluated, and collaborative decisions made about appropriate infection prevention and control measures. Ongoing guidance is also provided to facility staff through daily or more frequent telephone contact with Health Unit staff.

Influenza Activity Monitoring

Every year, staff members work with community partners to monitor and communicate influenza activity occurring locally and provincially. The indicators monitored are highlighted in a weekly influenza surveillance update that is posted on the Health Unit’s website and distributed via email distribution lists. The indicators include the following:

• hospital emergency reports regarding the percentage of patients presenting with fever and respiratory illness;
• reports of more than 10% absenteeism from schools;
• laboratory-confirmed cases of influenza reported by medical laboratories;
• outbreaks related to influenza in hospitals and long term care and retirement homes;
• sentinel x-ray provider reports regarding newly identified cases of bronchopneumonia;
• calls to Telehealth Ontario about respiratory and influenza-like illness;
• percentage of influenza tests performed by the Ontario Public Health Laboratory that are positive from across the province. 

To date, surveillance data indicate low levels of influenza virus circulating in the community with no institutional influenza outbreaks reported. Last season, the first institutional influenza outbreak was declared in September 2010. Another notable difference this outbreak season compared to last season pertains to refinements in laboratory testing methodologies that have allowed for earlier identification of non-influenza respiratory viruses. This has facilitated adaptation of outbreak control measures consistent with the specific respiratory virus that is identified.

This report was prepared by Ms. Eleanor Paget, Public Health Nurse, and Ms. Cathie Walker, Manager, Infectious Disease Control Team.

Graham L. Pollett, MD, FRCPC
Medical Officer of Health

This report addresses the following requirement(s) of the Ontario Public Health Standards:
The board of health shall interpret and use surveillance data to communicate on risks to relevant audiences in accordance with the Infectious Diseases Protocol and the Population Health Assessment and Surveillance Protocol.