Veterinary Epidemiology and Zoonosis

ANALYTICAL EPIDEMIOLOGY

• It is the analysis of observations by using the suitable diagnosis and statistical tests.

Observational studies

• It is similar to experimental study. Animals are allotted to groups with respect to certain characteristics they possess (trait, disease, etc).
• However it is not possible to assign animals to groups randomly because the investigator has little control over factors that are being studied, as the characteristics are inherent (Examples are sex, weight and diet).
• Usually the occurrence of a disease is known by estimating the morbidity and mortality rates.
• The estimation of mortality is straightforward whereas the morbidity rate is expressed as prevalence and incidence rate.
• To know these things two types of observational studies are undertaken. They are,
  • Cross sectional study
  • Longitudinal study