| Abstract | Infectious diseases, caused largely by microorganisms such as bacteria, viruses or helminths, are a global threat to both human and animal populations and a major cause of mortality and morbidity worldwide. This thesis studies the trajectory, transmission dynamics and the effects of climate change of infectious diseases. We first discuss our work on COVID-19, where we study the first wave of COVID-19 in India, using the INDSCI-SIM model. We then describe in some detail the dynamics of the pandemic during and after the second wave for the Indian state of Andhra Pradesh, including the effects of hybrid immunity, school reopening and the later Omicron wave in India. Finally, we discuss the role of environmental temperature in malaria transmission, studying the temperature dependent dynamics of the transmission of avian (Plasmodium relictum) and human Plasmodium parasites (P. vivax and P. falciparum) as well as two malaria‐like avian parasites, Haemoproteus and Leucocytozoon. Using detailed temperature records from four sites: low elevation (1800), mid elevation (2200 m), and high elevation (2600–3200 m) in the western Himalaya, we model how temperature regulates parasite development rate in the wild. We describe the use of models for future climate change to predict the potential impact of global warming on malaria transmission between the present year and the year 2040. |