Surveillance of Infectious Diseases refers to the continuous collection, analysis, and interpretation of data that is then used for planning and implementing public health actions with the aim of protecting further the health of the general public.
Through the above processes public health experts can monitor various factors related to infectious diseases, amongst which are:
1. the burden, or impact, of diseases on the population and on individuals
2. the epidemiology of disease, i.e. the way in which diseases spread within a population and the factors that affect the spread of that
disease
3. identification of outbreaks
4. monitoring for new pathogens (organisms that cause diseases)
Surveillance within the IDCU
There are different ways in which infectious disease surveillance is carried out.
The IDCU receives reports about cases from doctors, healthcare facilities and laboratories, which cases are investigated, and the data analysed as required.
In Malta there are currently 73 statutory notifiable infectious diseases under Article 27(a)(i) of the Public Health Act (Chapter 465 of the Laws of Malta). Notification is mandatory by law from all local laboratories and registered doctors working in Malta. Every notified case is verified by IDCU staff according to EU case definitions. Contact tracing is carried out and all the necessary preventive measures are taken to limit the spread of disease.
The IDCU also receives notifications from the mortality register/death certificates, other departments (e.g. food poisoning complaints from the Environmental Health Directorate) and also investigates complaints directly from the public.
Notifications can be made by email, telephone and through a dedicated online notification portal (this can only be accessed by doctors registered with the Malta Medical Council).
The IDCU also carried out active surveillance for certain infectious diseases. In Malta active surveillance for Acute Flaccid Paralysis (AFP)/Polio became effective in January 1998. The WHO polio group require information on children aged less than 15 years, so from 2003 AFP surveillance is concentrated on children under 15 years of age only. In the years before all ages were notified to the WHO group.
Since 2018, environmental surveillance of sewage water for polio was started. Samples are collected from the 3 main sewage plants in Malta and sent to the reference laboratory of the Istituto Superiore di Sanità in Italy. Here they are tested for the presence of polio virus. This is done twice a year.
Sentinel Surveillance:
Sentinel surveillance involves the monitoring of the rate of occurrence of particular diseases through a voluntary network of healthcare professionals or laboratories in order to evaluate whether there are any changes in the number of cases of the specific diseases within the population.
In Malta, sentinel surveillance of Influenza activity in the community has been underway since 2003. This involves a number of voluntary family doctors who report on Influenza activity in their practice with regards to Influenza like-illness (ILI). Once flu season starts they are also encouraged to swab patients with Influenza like-illness (ILI).
Syndromic Surveillance
The IDCU also carried out syndromic surveillance. This is the process of collecting, analysing and interpreting health-related data, that is received as early as possible when illness begins to provide overall population-based awareness of the spread of disease and aids in early warning and monitoring of public health impacts. Using information collected during routine patient care, syndromic surveillance can be based on signs/symptoms/preliminary diagnoses. This approach makes syndromic surveillance much timelier than surveillance requiring laboratory confirmed diagnoses. IDCU carries out syndromic surveillance on Severe Acute Respiratory Infections (SARI).
Analysis of Data
IDCU staff investigate all reported cases and all data collected is entered into a database and analysed. Reports are published regularly and collected data uploaded regularly (see section titled Library/Tables on the IDCU page).
Any necessary environmental action is coordinated through Environmental Health Officers within the Environmental Health Directorate. This mostly involves the Food Safety Unit and the Environmental Health Unit. The Health Screening Unit is responsible for data collection in cases of Tuberculosis. It also carries out public health preventive measures related to Tuberculosis including screening.