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Background: Climate change is expected to greatly increase exposure to flooding, particularly in urban populations in low- and middle-income countries. We examined within-city social disparities in exposure to flooding in 276 Latin American cities and associated features of the neighborhood urban environment., Methods: We used a spatially granular dataset of historical flood events from 2000 to 2018 to describe neighborhood flooding within cities across eight Latin American countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Guatemala, Mexico, and Panama). We estimated the percentage of the population living in flooded neighborhoods, described social disparities in flooding based on neighborhood educational attainment, and compared the magnitude of disparities across and within cities. We used multilevel models to examine how city- and neighborhood-level factors are related to neighborhood flooding., Results: We examined 44,698 neighborhoods in 276 cities from eight countries with a total of 223 million residents and 117 distinct flood events from 2000-2018. One in four residents in neighborhoods in the lowest education quintile lived in neighborhoods with flooding, compared to one in 20 residents of the highest neighborhood education quintile. Greater neighborhood flooding was associated with lower neighborhood-level educational attainment and with neighborhoods that were coastal, less dense (population or intersection), further from the city center, greener, and had steeper slopes. There was no association between city-level educational attainment and flooding., Conclusion: There are large social disparities in neighborhood flooding within Latin American cities. Residents of areas with lower education attainment face substantially higher risks of flooding. Policymakers must prioritize flood adaptation and recovery efforts in neighborhoods with lower socioeconomic position.

Over the past two decades, research on bat-associated microbes such as viruses, bacteria and fungi has dramatically increased. Here, we synthesize themes from a conference symposium focused on advances in the research of bats and their microbes, including physiological, immunological, ecological and epidemiological research that has improved our understanding of bat infection dynamics at multiple biological scales. We first present metrics for measuring individual bat responses to infection and challenges associated with using these metrics. We next discuss infection dynamics within bat populations of the same species, before introducing complexities that arise in multi-species communities of bats, humans and/or livestock. Finally, we outline critical gaps and opportunities for future interdisciplinary work on topics involving bats and their microbes.

Introduction: Interactions between the gut microbiome (GM) and the immune system influence host health and fitness. However, few studies have investigated this link and GM dynamics during disease in wild species. Bats (Mammalia: Chiroptera) have an exceptional ability to cope with intracellular pathogens and a unique GM adapted to powered flight. Yet, the contribution of the GM to bat health, especially immunity, or how it is affected by disease, remains unknown., Methods: Here, we examined the dynamics of the Egyptian fruit bats' ( Rousettus aegyptiacus ) GM during health and disease. We provoked an inflammatory response in bats using lipopolysaccharides (LPS), an endotoxin of Gram-negative bacteria. We then measured the inflammatory marker haptoglobin, a major acute phase protein in bats, and analyzed the GM (anal swabs) of control and challenged bats using high-throughput 16S rRNA sequencing, before the challenge, 24h and 48h post challenge., Results: We revealed that the antigen challenge causes a shift in the composition of the bat GM ( e.g., Weissella, Escherichia, Streptococcus ). This shift was significantly correlated with haptoglobin concentration, but more strongly with sampling time. Eleven bacterial sequences were correlated with haptoglobin concentration and nine were found to be potential predictors of the strength of the immune response, and implicit of infection severity, notably Weissella and Escherichia . The bat GM showed high resilience, regaining the colony's group GM composition rapidly, as bats resumed foraging and social activities., Conclusion: Our results demonstrate a tight link between bat immune response and changes in their GM, and emphasize the importance of integrating microbial ecology in ecoimmunological studies of wild species. The resilience of the GM may provide this species with an adaptive advantage to cope with infections and maintain colony health., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Berman, Weinberg, Moreno, Czirják and Yovel.)

Bats are particularly interesting vertebrates in their response to pathogens owing to extremes in terms of tolerance and resistance. Oxidation is often a by-product of processes involved in the acute phase response, which may result in antimicrobial or self-damaging effects. We measured the immunological and oxidative status responses of Egyptian fruit bats ( Rousettus aegyptiacus ) to a simulated bacterial infection using lipopolysaccharide injection. As expected, experimental bats exhibited increases in two humoral immunological markers. However, they surprisingly did not show any effects across two markers of oxidative damage and four antioxidant markers. We propose that this lack of effects on oxidative status may be due to a reduction in cell metabolism through sickness behaviours or given life history traits, such as a long lifespan and a frugivorous diet. Finally, the consistency in the pattern of elevation in haptoglobin and lysozyme between current and previous findings highlights their utility as diagnostic markers for extracellular infections in bats., (© The Author(s) 2022. Published by Oxford University Press and the Society for Experimental Biology.)

Along with its many advantages, social roosting imposes a major risk of pathogen transmission. How social animals reduce this risk is poorly documented. We used lipopolysaccharide challenge to imitate bacterial infection in both a captive and a free-living colony of an extremely social, long-lived mammal-the Egyptian fruit bat. We monitored behavioral and physiological responses using an arsenal of methods, including onboard GPS to track foraging, acceleration sensors to monitor movement, infrared video to record social behavior, and blood samples to measure immune markers. Sick-like (immune-challenged) bats exhibited an increased immune response, as well as classic illness symptoms, including fever, weight loss, anorexia, and lethargy. Notably, the bats also exhibited behaviors that would reduce pathogen transfer. They perched alone and appeared to voluntarily isolate themselves from the group by leaving the social cluster, which is extremely atypical for this species. The sick-like individuals in the open colony ceased foraging outdoors for at least two nights, thus reducing transmission to neighboring colonies. Together, these sickness behaviors demonstrate a strong, integrative immune response that promotes recovery of infected individuals while reducing pathogen transmission inside and outside the roost, including spillover events to other species, such as humans., (© 2021 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals LLC on behalf of New York Academy of Sciences.)