The twenty-first century has witnessed a wave of severe infectious disease outbreaks, not least the COVID-19 pandemic, which has had a devastating impact on lives and livelihoods around the globe. The 2003 severe acute respiratory syndrome coronavirus outbreak, the 2009 swine flu pandemic, the 2012 Middle East respiratory syndrome coronavirus outbreak, the 2013–2016 Ebola virus disease epidemic in West Africa and the 2015 Zika virus disease epidemic all resulted in substantial morbidity and mortality while spreading across borders to infect people in multiple countries. At the same time, the past few decades have ushered in an unprecedented era of technological, demographic and climatic change: airline flights have doubled since 2000, since 2007 more people live in urban areas than rural areas, population numbers continue to climb and climate change presents an escalating threat to society. In this Review, we consider the extent to which these recent global changes have increased the risk of infectious disease outbreaks, even as improved sanitation and access to health care have resulted in considerable progress worldwide.

No abstract

No abstract

As human population density continues to increase exponentially, speeding the reduction and fragmentation of primate habitat, greater human-primate contact is inevitable, making higher rates of pathogen transmission likely. Anthropogenic effects are particularly evident in Madagascar, where a diversity of endemic lemur species are threatened by rapid habitat loss. Despite these risks, knowledge of how anthropogenic activities affect lemur exposure to pathogens is limited. To improve our understanding of this interplay, we non-invasively examined six species of wild lemurs in Ranomafana National Park for enteric bacterial pathogens commonly associated with diarrheal disease in human populations in Madagascar. Patterns of infection with Enterotoxigenic Escherichia coli, Shigella spp., Salmonella enterica, Vibrio cholerae, and Yersinia spp. (enterocolitica and pseudotuberculosis) were compared between lemurs inhabiting intact forest and lemurs inhabiting degraded habitat with frequent exposure to tourism and other human activity. Fecal samples acquired from humans, livestock, and rodents living near the degraded habitat were also screened for these bacteria. Remarkably, only lemurs living in disturbed areas of the park tested positive for these pathogens. Moreover, all of these pathogens were present in the human, livestock, and/or rodent populations. These data suggest that lemurs residing in forests altered or frequented by people, livestock, or peridomestic rodents, are at risk for infection by these diarrhea-causing enterobacteria and other similarly transmitted pathogens.

Health and nutritional assessments of wildlife are important management tools and can provide a means to evaluate ecosystem health. Such examinations were performed on 37 white-fronted brown lemurs (Eulemur fulvus albifrons) from four sites in Madagascar. Comparison of health parameters between sites revealed statistically significant differences in body weight, body temperature, respiratory rate, hematology parameters (white cell count, hematocrit, segmented neutrophil count, and lymphocyte count), serum chemistry parameters (aspartate aminotransferase, alanine aminotransferase, serum alkaline phosphatase, total protein, albumin, phosphorus, calcium, sodium, chloride, and creatinine phosphokinase), and nutrition parameters (copper, zinc, ferritin, retinol, tocopherol, and 25-hydroxycholecalciferol). Two of 10 lemurs tested were positive for toxoplasmosis; none of 10 were positive for Cryptosporidium or Giardia. Enteric bacteria and endo- and ectoparasites were typical. Statistically different values in hematology and chemistry values probably do not reflect clinically significant differences, whereas nutrition parameter differences are likely related to season, soil, and forage availability.