From such studies various ways of controlling the infection can be considered, such
as reducing the level of faecal contamination and treatment of the fisherman, health
education and wearing protective clothing and timing the treatment to coincide with the
rise and fall of the water levels.
n SUMMARY
Epidemiology is the study of the distribution of diseases in a given environment. A com-
plete survey requires background data such as the local topography, climate, population
size, sex ratio, age distribution, housing and occupations. Data are often obtained from local
hospitals and health centres which may represent a true survey of all the local diseases.
Examination of faecal, blood and urine samples are the most common methods of diag-
nosis. Once an overall view is gained of the parasites present and their distribution, methods
of treatment and control have to be considered.End of chapter questions
Question 8.1 What is meant by epidemiology?
Question 8.2 What type of data is necessary for the study of the distribution of a parasitic
infection?
Question 8.3 Where do most data collections begin and why?
Question 8.4 What type of diagnostic techniques is used to detect parasitic infections?
Question 8.5 Using actual examples explain how the local topography may account for
the types of parasitic infections.
Question 8.6 What is meant by polyparasitism?
Question 8.7 Describe some examples of incidences of polyparasitism.
Question 8.8 Give examples how migratory behaviour can result in becoming infected
with parasites.
Question 8.9 What results were obtained by a study of schistosome infections in
Senegal?
Question 8.10 Discuss the findings of a study of a community where there is endemic
schistosomiasis.
EPIDEMIOLOGY