It is defined as a system of close observation of all aspects of the occurrence and distribution of a given disease through the systematic collection, analysis, interpretation and distribution of relevant information pertaining to a particular disease.

The primary goal of public health surveillance is the reduction of illness, disability and death through the control and/or prevention of disease. Besides causing illness, disability and death, communicable diseases have a substantial social and economic impact on individual, family and community development. The epidemiology and Surveillance Unit of the Department of Health, is responsible for communicable disease surveillance in Bermuda. Under the Public Health Act of 1949, there is a list of communicable diseases that must be reported to the Department of Health. While physicians primarily have the legal responsibility to report a communicable disease, other health and allied health professions can report as well. Not reporting prevents awareness of potential outbreaks and a delay in the response to the outbreak.

Here is a list of some of the notifiable diseases: Acquired Immune deficiency Syndrome (AIDS), HIV, Hepatitis, Sexually Transmitted Diseases, Tuberculosis, chicken pox, mumps, measles, rubella (German Measles), influenza, streptococcal infections (including Scarlet Fever), food and water borne illnesses i.e., salmonella, giardia, compylobactor, bacillus cereus etc., bacterial meningitis, and gastroenteritis.

There are some diseases that are not notifiable, but should be reported because they require follow-up and specific control measures. They are, methicillin-resistant staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), legionellosis, and toxoplamosis and cryptosporidiosis in non-HIV positive persons.

The objectives of surveillance are to: a: Define the problem.

b: Define priorities.

c: Decide objectives.

d: Determine strategy.

e: Evaluate control and prevention measures.

f: Suggest further research/investigation.

Surveillance can be passive or active. Passive surveillance is the routine reporting of the number of cases of a disease initiated by the reporting site.

This can be done by mailing the data or telephoning the data to the Unit. In active surveillance, the reporting site is contacted on Wednesday of every week, and specifically asked about the occurrence of notifiable diseases.

The surveillance system also includes laboratory surveillance and hospital surveillance. Laboratory surveillance is regular monitoring of laboratory reports for the main purpose of identifying the organisms that cause the diseases under surveillance. This is mainly to confirm the diagnosis of the diseases reported.

It must be mentioned that all information is kept confidential. Protecting confidentiality means collecting and transmitting only necessary data i.e., age, gender and risk factor, involving only staff members who need to work on the data, and keeping surveillance records secure to protect the identification of individuals.

Once the reports are prepared, the information is disseminated to those individuals who have participated in the surveillance programme, as well as those who have a responsibility for preventive action. Reports are also sent abroad to international health agencies such as the World Health Organization, the Pan American Health Organization and the Caribbean Epidemiology Center.

Wile surveillance is an important part of the role of public health, it can only be successful if everyone who has a specific role recognises their role and participates fully. Remember an early warning system quickly activates a public health response, timely preparedness and effective planning and implementation of disease control.

Rhonda Daniels Nurse Epidemiologist HEALTH & SOCIAL ISSUES HTH