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Raccoons are host to diverse gastrointestinal parasites, but little is known about the ecology of these parasites in terms of their interactions with each other during coinfections, their interactions with host physiology and environmental factors, and their impact on raccoon health and survival. As a first step, we investigated the patterns of parasite infection and their demographic distribution in an urban-suburban population of raccoons trapped in the summers and autumns of 2018 and 2019. We collected faecal samples, demographic data, morphometric measurements, and blood smears, and used GPS data to classify trapping location by land cover type. Faecal floats were performed to detect and quantify gastrointestinal nematode eggs and coccidia oocysts, and white blood cell differentials were performed on blood smears to characterise white blood cell distributions. Data were analysed cross-sectionally and, where possible, longitudinally, using generalised linear models. Overall, 62.6% of sampled raccoons were infected with gastrointestinal nematodes, and 82.2% were infected with gastrointestinal coccidia. We analysed predictors of infection status and faecal egg count for three different morphotypes of nematode— Baylisascaris , strongyle, and capillariid nematodes—and found that infection status and egg count varied with Year, Month, Age class, Land cover, and coinfection status, though the significance of these predictors varied between nematode types. Gastrointestinal coccidia prevalence varied with Year, Month, Age class, strongyle infection status, and capillariid infection status. Coccidia oocyst counts were lower in adults and in October, but higher in females and in raccoons trapped in areas with natural land cover; furthermore, coccidia oocysts were positively associated with capillariid faecal egg counts. We found no evidence that gastrointestinal parasites influenced raccoon body condition or overwinter mortality, and so conclude that raccoons, though harbouring diverse and abundant gastrointestinal parasites, may be relatively tolerant of these parasites. [Display omitted] • Predictors of raccoon nematode infection vary but include Year, Month, Age class, Land cover, and coinfection status. • Coccidia infection status varies with Year, Month, Age class, strongyle infection status, and capillariid infection status. • Our results suggest that raccoons acquire immunity to nematodes but not coccidia. • Gastrointestinal parasites were not associated with body condition or juvenile overwinter mortality. [ABSTRACT FROM AUTHOR]

Many disease systems exhibit complexities not captured by current theoretical and empirical work. In particular, systems with multiple host species and multiple infectious agents (i.e., multi-host, multi-agent systems) require novel methods to extend the wealth of knowledge acquired studying primarily single-host, single-agent systems. We outline eight challenges in multi-host, multi-agent systems that could substantively increase our knowledge of the drivers and broader ecosystem effects of infectious disease dynamics. [ABSTRACT FROM AUTHOR]

Cholera dynamics in endemic regions display regular seasonal cycles and pronounced interannual variability. We review here the current quantitative evidence for the influence of climate on cholera dynamics with reference to the early literature on the subject. We also briefly review the incipient status of mathematical models for cholera and argue that these models are important for understanding climatic influences in the context of the population dynamics of the disease. A better understanding of disease risk related to the environment should further underscore the need for changing the socioeconomic conditions conducive to cholera. [Copyright &y& Elsevier]