Case study based on real-life investigations undertaken in Trinidad and Tobago in 1998-1999 and published in Clinical Infectious Diseases and the West Indian Medical Journal. Focus on laboratory-based surveillance of Salmonella in Trinidad and Tobago in 1998-1999, leading to a case-control study of risk factors for salmonellosis, and to control measures.  

Target audience: Public health practitioners with knowledge of basic epidemiologic concepts, especially non-epidemiologists (e.g., laboratorians, environmental health specialists, sanitarians, public health nurses, veterinarians, MPH students)

Level of case study: Basic

Teaching materials required: Graph paper, calculator

Time required: 3-4 hours

Objectives:

• Describe the signs and symptoms, means of diagnosis, and control of salmonellosis;
• Describe how Salmonella serotyping can be used in public health practice;
• Given a disease, describe the desired characteristics of a surveillance system for that disease;
• Discuss how the inclusion of the laboratory in the surveillance of a disease impacts the characteristics of the surveillance system and the usefulness of the data;
• Calculate the incidence of  a disease if given the number of cases and population size;
• Characterize a health problem by time, place, and person (e.g., perform the descriptive epidemiology); and
• Create and interpret a graph; Interpret the measure of association for a case-control study.