Browsing by Author "Carroll, Darin S."

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    Effects of anthropogenic and demographic factors on patterns of parasitism in African small mammal communities
    (Parasitology, 2015) Salzer, Johanna S.; Carroll, Darin S.; Newkirk, Amanda Jo Williams; Lang, Stefanie; Peterhans, Julian Kerbis; Rwego, Innocent B.; Ockers, Sandra; Gillespie, Thomas R.
    Habitatdisturbance oftenresults in alterations in community structure of smallmammals.Additionally, the parasitesharboured by these small mammals may be impacted by environmental changes or indirectly affected by changes in available hosts. To improve our understanding of this interplay, we examined the patterns of parasitism in small mammal communities from a variety of habitats in forested Uganda. Small mammals were collected from areas experiencing variable habitat disturbance, host densityandspecies richness.The analysis focusedon3most abundant rodent species,Lophuromys aquilus,Praomys jacksoni and Hylomyscus stella, and a diverse group of parasites they harbour. The impact of various habitat and host community factors on parasite prevalence was examined using linear regression and Spearman’s rank-order correlation. We further investigated the parasite communities associated with each individual using correspondence analysis. We determined that, parasite prevalence and richness may be occasionally influenced by community and habitat factors, but taxonomy is a driving force in influencing the parasite community harboured by an individual host. Ultimately, applying general principles across a broad range of disturbance levels and diverse host communities needs to be approached with caution in complex communities.
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    Impact of Anthropogenic Disturbance on Native and Invasive Trypanosomes of Rodents in Forested Uganda
    (EcoHealth, 2016) Salzer, Johanna S.; Pinto, C. Miguel; Grippi, Dylan C.; Newkirk, Amanda Jo Williams; Peterhans, Julian Kerbis; Rwego, Innocent B.; Carroll, Darin S.; Gillespie, Thomas R.
    Habitat disturbance and anthropogenic change are globally associated with extinctions and invasive species introductions. Less understood is the impact of environmental change on the parasites harbored by endangered, extinct, and introduced species. To improve our understanding of the impacts of anthropogenic disturbance on such host–parasite interactions, we investigated an invasive trypanosome (Trypanosoma lewisi). We screened 348 individual small mammals, representing 26 species, from both forested and non-forested habitats in rural Uganda. Using microscopy and PCR, we identified 18% of individuals (order Rodentia) as positive for trypanosomes. Further phylogenetic analyses revealed two trypanosomes circulating—T. lewisi and T. varani. T. lewisi was found in seven species both native and invasive, while T. varani was identified in only three native forest species. The lack of T. varani in non-forested habitats suggests that it is a natural parasite of forest-dwelling rodents. Our findings suggest that anthropogenic disturbance may lead to spillover of an invasive parasite (T. lewisi) from non-native to native species, and lead to local co-extinction of a native parasite (T. varani) and native forest-dwelling hosts.
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    Serologic Evidence For Circulating Orthopoxviruses In Peridomestic Rodents From Rural Uganda
    (Journal of wildlife diseases, 2013) Salzer, Johanna S.; Carroll, Darin S.; Rwego, Innocent B.; Li, Yu; Falendysz, Elizabeth A.; Shisler, Joanna L.; Karem, Kevin L.; Damon, Inger K.; Gillespie, Thomas R.
    The prevalence of orthopoxviruses (OPXV) among wildlife, including monkeypox virus (MPXV), remains largely unknown. Outbreaks of human monkeypox in central Africa have been associated with hunting, butchering, and consuming infected forest animals, primarily rodents and primates. Monkeypox cases have not been reported in east Africa, where human contact with wildlife is more limited. Whether this lack of human disease is due to the absence of MPXV in rodents is unknown. However, testing of wildlife beyond the known geographic distribution of human cases of monkeypox has rarely been conducted, limiting our knowledge of the natural distribution of MPXV and other OPXV. To improve our understanding of the natural distribution of OPXV in Africa and related risks to public health, we conducted a serosurvey of peridomestic rodents (Rattus rattus) in and around traditional dwellings in Kabarole District, Uganda, from May 2008 to July 2008. We tested for OPXV antibody in areas free of human monkeypox. Sera from 41%of the R. rattus individuals sampled reacted to OPXV-specific proteins from multiple, purified OPXV samples, but did not react by enzyme-linked immunosorbent assay. The specific OPXV could not be identified because poxvirus DNA was undetectable in corresponding tissues. We conclude that an OPXV or a similar poxvirus is circulating among wild rodents in Uganda. With the known geographic range of OPXV in rodents now increased, factors that dictate OPXV prevalence and disease will be identified.