ABSTRACT
Omran's classic model of epidemiological transition explains how changing disease patterns affected the demography of affluent societies in years leading up to and during the Industrial Revolution. Although this transition helps explain complex interactions between economy, demography, and disease, the model has two important shortcomings. The first is the historical, and the second is for addressing changes in affluent societies. Only a few of the human cases of highly pathogenic avian influenzas detected since 1997 can reasonably be attributed to human-to-human transmission. The first epidemiological transition brought high mortality and fertility rates, with expansions in overall population size but without significant changes in the proportions of the elderly. The second transition brought declining mortality and fertility rates, leading to even greater population expansion due to declining childhood infectious diseases.
