Differences in cynomolgus macaque populations used for infectious disease research

Cynomolgus macaques, a species of Old World primate native to southeastern and eastern Asia and the island of Mauritius, are one of the most important nonhuman primate models for infectious disease. Although the closely related rhesus macaque is classified into subspecies based on geographic origin, no such subdivision exists for cynomolgus macaques, and they continue to be used interchangeably in infectious disease research, reducing the comparability of data produced from these studies. Research into the population genetics of cynomolgus macaques has found significant differences between macaques native to different areas, including their genetic diversity, with macaques from insular populations such as Mauritius and the Philippines exhibiting highly restricted heterozygosity compared to mainland populations native to Indonesia or Cambodia. In the context of infectious disease studies, research into pathogens, including Ebola virus, Crimean-Congo hemorrhagic fever virus, and Mycobacterium tuberculosis have found differences in study outcomes, survival times, and immune cell responses between different populations of macaques. This review provides an overview of the differences between cynomolgus macaque populations in the context of genetic diversity, and in response to infection, and highlights the need for clear reporting of geographic origin of primates used in research. This will improve data comparison between studies and help to further refine this important animal model.