This chapter highlights the potential of an integrated palaeopathological approach for unravelling the evolutionary history of shared human and animal pathogens. The transfer of pathogens between animals and humans has occurred for millennia and remains a public health issue today, as evidenced by the Covid-19 pandemic. Although the focus has traditionally centred on pathogens transmitted from animals to humans (zoonoses), the direction of transmission is also often the other way (reverse zoonoses). The best way to understand the cross-species transfer of pathogens is by investigating the conditions that make it possible for a new host, whether human or animal, to be infected. As societies transitioned from hunting and foraging to herding and farming, and from living in rural to urban settings, and in increasingly industrialised environments, dramatic changes occurred in their relationships with animals. These changes had major impacts on pathogen evolution. In particular, the new opportunities for transmission affected pathogen virulence and distribution. This chapter investigates the factors driving transmission of Taenia tapeworms, Mycobacteria, Plasmodium falciparum, Brucella, Burkholderia mallei and the morbilliviruses in domestic environments. It draws evidence from palaeopathology, historical sources, molecular analysis, paleoenvironmental data and medical/veterinary clinical literature. This approach helps explain why these pathogens became problematic when and where they did, and it identifies factors that are likely to contribute to future outbreaks. The chapter concludes with a reflection on the ways an interdisciplinary understanding of past diseases provides insights for current and future epidemics.