The health surveillance system is an essential tool for measuring and monitoring the population’s health status.
It is used to monitor common diseases and deaths, and give warning at the beginning of an outbreak or if the situation in the camp worsens.
All levels of the health care system, hospitals, health centres and health posts, and all other health care structures, as well as the community health workers, contribute to data collection.
A good surveillance system should be as simple as possible and relies on three categories of data: demographic data, the number of deaths and the number of consultations by disease.
This category is key in determining the size and composition of the displaced population.
It is also used as the denominator when calculating the mortality and morbidity indicators.
The demographic data basically count the total population, the number of children under 5 years, the sex distribution and the number of arrivals and departures.
The population can be estimated mainly by:
- counting the dwellings by camp sector;
- taking a census or registering the displaced;
- using programme activities – immunisation, in particular.
Knowing the age and sex distribution of the population makes it possible to ask the right questions and target at-risk groups.
The mortality rate is the key indicator for measuring the seriousness of a situation.
In emergency situations, the threshold has been set at 1 death per 10,000 per day, i.e. twice the rate in “non-crisis” situations.
For children under 5 years, the threshold is 2 deaths per 10,000 per day.
While the death count in health care facilities is useful, it is often insufficient, because many people die in their shelters. It must therefore be supplemented with the overall mortality at the site or camp.
Mortality surveillance is done in different ways:
- using a community surveillance system in which community health workers record the deaths, births, arrivals and departures in their sector once a week;
- or by counting graves or the number of shrouds distributed.
The morbidity indicator looks at common conditions – that is, diarrhoea, malnutrition, acute respiratory infections and malaria – and diseases with epidemic potential, like meningitis, cholera and measles.
Here, the health care facilities are the main source of information,
by recording the number of consultations per disease.
Clinical case definitions are developed for each of these diseases; they should be simple enough for the health care staff to use, and thus help determine the incidence of each disease within the displaced or refugee population.
The surveillance system provides useful quantitative data that can be used to trigger an emergency plan or reorientate operations, by showing how the situation is changing over time.
It can also be used to assess resource needs.