Intellectual Merit 

We characterized Allee effects (AEs) on pathogen persistence and transmission in a socially structured, group-living species, the banded mongoose in Northern Botswana. While AEs were important in predicting group demographic dynamics, they did not moderate pathogen persistence potential. Rather, troops with more persistent disease had more variable troop sizes than those without disease (n=76 troop-years), suggesting pathogen transmission and persistence is driven by more complex environment-host-pathogen interactions. Group extinction thresholds are identified (n=6 mongoose, n=21 study years), with constraints on minimum groups size influenced likely by resource availability.

We constructed dynamic models of pathogen transmission including a network transmission model from indirect and direct social networks. We also evaluated methods to predict the epidemic threshold for temporal contact network models and identify areas that remain unexplored. We characterized our model system allowing for enhanced understanding of pathogen-host-landscape interactions including the influence of humans on these dynamics and improved model development. Banded mongooses in our study site had significantly higher within-troop aggression levels when foraging in garbage compared to other foraging habitats. Our data suggest that mongoose troops that forage in garbage may be at greater risk of acquiring TB by incurring injuries that may allow for pathogen invasion. Our study suggests the need to consider the indirect effects of garbage on behavior and wildlife health when developing waste management approaches in human-modified areas. Although banded mongoose are territorial, den use by troops other than the resident troop was observed, but only for anthropogenic dens sites. These space-sharing behaviors can significantly impact pathogen transmission dynamics and disease spread in these human-modified landscapes. Mongooses living in association with humans was more concentrated in the dry season than the wet season, when historically accepted ecological theory predicted more dispersed space use. Resource richness factors such as building density were associated with space use only during the dry season underscoring the important influence urban environments can have on modifying wildlife behavior. There is growing need to explicitly incorporate human–animal interactions into ecological theory and research. We also identify nocturnal space use in this diurnal species independent of lunar phase. Enhanced understanding of  wildlife activity patterns might provide new insights into the interaction between ecological phenomenon and species biology that spans the diurnal–nocturnal spectrum. 

Banded mongooses also exhibited seasonal chronic glucocorticoid elevation, associated primarily with food limitation and secondarily with reproduction. Magnitude and duration of this elevation suggests that this may be maladaptive for some animals, with possible fitness consequences. In late dry season, this population may face a convergence of stressors (food limitation, agonistic encounters at concentrated food resources, evictions, estrus, mate competition, parturition, and predation pressure on pups), which may induce homeostatic overload. These dynamics may underpin the more seasonal presentation of this TB disease. 

In this study, we also fully characterized the pathological and clinical presentation of M. mungi in the banded mongoose host. We identify primary environmental transmission that occurs in association with social communication behavior. We have detected differences in lipid production in anal gland secretions collected from healthy and infected mongoose. We also note significant differences in the mongoose gut microbiome structure when Mycobacterium spp. are detected as part of the gut microbial community, particularly a positive correlation between Mycobacterium and members of the family Rhizobiaceae, and a negative correlation with the family Bacteroides. 
We also identified bidirectional interactions between land use, vigilance, group size, and olfactory behaviors that influence pathogen transmission dynamics, creating the potential for spatial hot spots of transmission. We identified dispersal estimates through microsatellite markers across land type; sequenced the genome of both host (banded mongoose) and the nonculturable tuberculosis (TB) pathogen, M. mungi. We created a novel transcriptomic marker assay for disease state detection, and cementum aging approaches to improve the tractability of this host-pathogen systems, applications that have broad impacts to studying wildlife across systems. 

Broader impacts

This work has contributed to 16 publications, one book chapter, and six conference presentations. The project has trained USA and Botswana scholars including 27 undergraduate students, 17 REU participants, 7 veterinary students, 11 graduate students (1 Botswana citizen, 1 Botswana government biologist), 8 postdoctoral associates, 25 Botswana field and lab technicians and numerous Botswana Government officers (>15). A field-based course was developed (6 units) and delivered in 2019 and 2022 in Botswana to a total of 17 USA undergraduates (some under minority REU funding) and one Botswana undergraduate. Eight minority USA high school students/teachers traveled to the study site for experiential learning in 2019 and 1 teacher and two students in 2022. The project educational program was delivered across 12 schools to more than 420 children per week across years reaching thousands of children. Outputs of this project have informed wildlife management approaches in Botswana, communicated across the Botswana Government ministries and departments. 

Last Modified: 05/27/2024
Modified by: Kathleen A Alexander