1 - Epidemic theory: Studying the effective and basic reproduction numbers, epidemic thresholds and techniques for the analysis of infectious diseases with particular emphasis on tuberculosis

Abstract

Basic reproduction number (BRN) plays a significant role in studying communicable diseases in the starting phase of an epidemic. However, when the disease spreads in the population, the effective reproduction number replaces it taking the primary role in the study of disease dynamics. This book deals with the significance of basic and effective reproduction numbers in the study of communicable diseases, their threshold behavior, and different approaches to determine them in a mathematical model. Starting with the history of mathematical epidemiology and determination of BRN using deterministic and stochastic approaches, this chapter presents a brief introduction of all the terms required to be aware of while studying BRN such as herd immunity, epidemic curve, index cases, primary cases, generation time, and serial interval. This chapter also covers the scope of exception reporting, clusters, and study of BRN using epidemic curve and serial interval distribution. The next-generation matrix (NGM) method to determine BRN is discussed in detail. In addition, a mathematical model on multidrug-resistant tuberculosis (MDR-TB) has been formulated and its BRN is determined by the NGM approach. A brief review of BRN for tuberculosis (TB) disease is also given in the chapter to emphasize the role of studying BRN in its control.