The use of epidemiological tools in conflict-affected populations: open-access educational resources for policy-makers

Table of Contents

1. Welcome
2. Introduction: Epidemiology in crises
3. Ethical issues in data collection
4. Need for epidemiologic competence
5. Surveys - Introduction
6. Surveys - Description of sampling methods
7. Surveys - Sampling error, bias, accuracy, precision, & sample size
8. Surveys - Resources required for surveys
9. Surveys - Critiquing survey reports
10. Surveillance - When to do surveillance
11. Surveillance - Methods
    1. Comparison with other data collection methods
    2. Morbidity surveillance
    3. Mortality surveillance
    4. Types of surveillance
    5. Case definitions
    6. Data flow
12. Surveillance - Common problems
13. Programme data
14. Rapid assessment
15. Mortality - Indicators and their measurement
16. Mortality - Data sources
17. Mortality - Interpretation and action
18. Nutrition - Introduction and background
19. Nutrition - Indicators and their measurement
20. Nutrition - Data sources
21. Nutrition - Interpretation and action
22. Health services
23. Vaccination programmes
24. Water supply, sanitation, and shelter
25. Violence
26. Presentation of results
27. Formulating conclusions and recommendations
28. Dissemination and action

Morbidity surveillance

(go to Outline)

In emergencies, surveillance is often done for specific diseases. Most commonly, diseases of two types are included in surveillance:

• Those which cause substantial morbidity and/or mortality and need to be controlled, such as malaria, viral diarrhoea, pneumonia (also called lower respiratory infection, or LRI), etc.

• Those which can occur in rapidly developing outbreaks which may cause substantial morbidity and/or mortality, such as measles, meningitis, yellow fever, cholera, etc.

A typical surveillance form completed by health care workers in clinics might look like this:

This form is much simpler than the forms for communicable diseases used in developed countries or in stable populations because:

• Health workers generally do not have access to laboratory facilities; their diagnoses are based only on clinical signs and symptoms and,

• Health workers are often very busy and do not have time to collect much data on each patient.

Health workers merely put a tick in the appropriate box to record each patient. As a result, public health authorities who analyze the data can only count the number of cases for each age and sex group. They know nothing about each individual case.