S.N.H. Putt, A.P.M. Shaw, A.J. Woods, L. Tyler and A.D. James

Veterinary Epidemiology and Economics Research Unit,

Department of Agriculture,

University of Reading, Reading,

Berkshire, England

First published in January 1987

Second edition, March 1988

Original English

Designed and printed at ILCA

Typeset on Linotype CRTronic 200 in Baskerville 10pt and Helvetica

ISBN 92-9053-076-6

*This electronic document has been scanned using optical character recognition
(OCR) software and careful manual recorrection. Even if the quality of digitalisation
is high, the FAO declines all responsibility for any discrepancies that may exist
between the present document and its original printed version.*

**1. An introduction to the planning and evaluation of disease control policy**

1.1 Introduction

1.2 The planning process1.2.1 The systems approach to livestock development

1.2.2 Stages in the planning process

1.2.3 The role of various disciplines in the planning process

**2. Epidemiology: some basic concepts and definitions**

2.1 Introduction

2.2 Intrinsic determinants of disease2.2.1 Disease agents as determinants of disease

2.2.2 Host determinants2.3 Extrinsic determinants of disease

**3. The use of descriptive statistics in the presentation of epidemiological data**

3.1 Introduction

3.2 Tables and graphs

3.3 Bar and pie charts

3.4 Classification by variable

3.5 Quantification of disease events in populations

3.6 Methods of summarising numerical data

**4. The epidemiological approach to investigating disease problems**

4.1 Introduction

4.2 Types of epidemiological study4.2.1 Prospective studies

4.2.2 Retrospective studies

4.2.3 Cross-sectional-studies4.3 Sampling techniques in epidemiological studies

4.3.1 Random sampling

4.3.2 Multi-stage sampling

4.3.3 Systematic sampling

4.3.4 Purposive selection

4.3.5 Stratification

4.3.6 Paired samples

4.3.7 Sampling with and without replacement4.4.1 Sample sizes for estimating disease prevalence in large populations

4.4.2 Sample sizes needed to detect the presence of a disease in a population4.5 Methods for obtaining data in epidemiological studies

4.5.1 Interviews and questionnaires

4.5.2 Procedures involving measurements

4.5.3 Errors due to observations and measurements4.6 Basic considerations in the design of epidemiological investigations

4.8 Monitoring and surveillance

4.8.1 Epidemiological surveillance

4.8.2 Epidemiological monitoring

**5. Statistical methods in the analysis of epidemiological data**

5.1 Introduction

5.2 Estimating population parameters5.2.1 Estimating a population mean

5.2.2 Sample size needed to estimate a population mean

5.2.3 Estimating a population proportion or rate from a simple random sample

5.2.4 Estimating a rate or proportion from a cluster sample5.3 Formulating and testing statistical hypotheses in large-sized samples

5.3.1 Testing for a difference in two means

5.3.2 Testing for a difference in two proportions

5.3.3 Sample size for detecting differences between two proportions in prospective and cross-sectional studies

5.3.4 Sample size for detecting differences between two proportions in retrospective studies

5.3.5 Testing for differences in prevalence between several groups simultaneously

5.3.6 Testing for differences in several means simultaneously5.4 Formulating and testing hypotheses in small-sized samples

5.5 Matched comparisons

5.6 A word of warning

5.7 Linear correlation and regression

5.8 Time series

6.1.1 Basic philosophy

6.1.2 Application of economics disease control policy6.2 Prices appropriate for use in economic analyses

6.2.1 Theoretical aspects

6.2.2 Opportunity cost and the choice of prices in economic analysis

6.2.3 Adjusting for inflation - price conversions and price indexes6.3 Compound interest, discounting, annual rates of growth and annual loan repayments

6.3.1 Simple vs compound growth (or interest) rates

6.3.2 Discounting and compounding tables

6.3.3 Estimating present and future values using annuity tables

6.3.4 Loan repayments

6.3.5 Interest or discount rates and inflation

**7. Estimating the costs of diseases and the benefits of their control**

7.1 Introduction

7.2 Economic aspects of livestock production systems7.2.1 Inputs and outputs

7.2.2 Factors influencing output and offtake

7.2.3 The relationship between livestock prices and output7.3 Estimating the cost of disease

7.3.1 Quantifying the direct losses due to disease

7.3.2 Methods for estimating annual losses

7.3.3 Losses due to disease acting as a constraint on production

7.3.4 Other losses due to animal diseases

7.3.5 Secondary effects, externalities and intangible effects7.4 The costs of controlling disease

7.4.1 Introduction

7.4.2 The components of disease control costs

7.4.3 The importance of fixed and variable costs in planning disease control policy

**8. Economics and decision-making in disease control policy**

8.1 Introduction

8.2 The principles of partial analysis

8.3 The principles and criteria of benefit-cost analysis8.3.1 The role of the discount rate

8.3.2 Dealing with inflation

8.3.3 Layout of a benefit-cost analysis

8.3.4 The decision-making criteria

8.3.5 Dealing with risk and uncertainty

8.3.6 The scope of a benefit-cost analysis

**References and recommended reading**

**Appendix two: modelling in veterinary epidemiology and economics**

1. Introduction

2. Types of model

3. Examples of models used in veterinary epidemiology and economics3.1 The basic parameters required for herd modelling

3.2 Dynamic herd models

3.3 Incorporating the effect of disease into herd models

3.4 Static herd productivity model