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St. Louis, MO, United States

Pacheco M.A.,Arizona State University | Battistuzzi F.U.,Arizona State University | Junge R.E.,St. Louis Zoo | Cornejo O.E.,Stanford University | And 6 more authors.
BMC Evolutionary Biology | Year: 2011

Background: Timing the origin of human malarias has been a focus of great interest. Previous studies on the mitochondrial genome concluded that Plasmodium in primates, including those parasitic to humans, radiated relatively recently during a process where host switches were common. Those investigations, however, assumed constant rate of evolution and tightly bound (fixed) calibration points based on host fossils or host distribution. We investigate the effect of such assumptions using different molecular dating methods. We include parasites from Lemuroidea since their distribution provides an external validation to time estimates allowing us to disregard scenarios that cannot explain their introduction in Madagascar. Results: We reject the assumption that the Plasmodium mitochondrial genome, as a unit or each gene separately, evolves at a constant rate. Our analyses show that Lemuroidea parasites are a monophyletic group that shares a common ancestor with all Catarrhini malarias except those related to P. falciparum. However, we found no evidence that this group of parasites branched with their hosts early in the evolution of primates. We applied relaxed clock methods and different calibrations points to explore the origin of primate malarias including those found in African apes. We showed that previous studies likely underestimated the origin of malarial parasites in primates. Conclusions: The use of fossils from the host as absolute calibration and the assumption of a strict clock likely underestimate time when performing molecular dating analyses on malarial parasites. Indeed, by exploring different calibration points, we found that the time for the radiation of primate parasites may have taken place in the Eocene, a time consistent with the radiation of African anthropoids. The radiation of the four human parasite lineages was part of such events. The time frame estimated in this investigation, together with our phylogenetic analyses, made plausible a scenario where gorillas and humans acquired malaria from a Pan lineage. © 2011 Pacheco et al; licensee BioMed Central Ltd. Source


Kozlowski C.P.,St. Louis Zoo | Kozlowski C.P.,University Of Missourist Louis | Hahn D.C.,U.S. Geological Survey
Wilson Journal of Ornithology | Year: 2010

We studied androgen production during development in nestling Eastern Screech-Owls (Megascops asio) and hypothesized that gender and hatch order might influence serum levels of testosterone and androstenedione. Testosterone levels were highest immediately after hatching and declined significantly in the 4 weeks leading to fledging. The average level of testosterone for 17 day-old owls was 3.99 ± 0.68 ng/ml. At 2228 days of age, the average testosterone level for nestling owls was 0.83 ± 0.18 ng/ml. Testosterone levels did not differ between males or females. The average testosterone level for male nestlings was 2.23 ± 0.29 ng/ml and 2.39 ± 0.56 ng/ml for female nestlings. The average level of androstenedione for nestling owls was 1.92 ± 0.11 ng/ml and levels remained constant throughout development. Levels were significantly higher in males than females. The average androstenedione level was 1.77 ± 0.16 ng/ml for male nestlings and 1.05 ± 0.24 ng/ml for female nestlings. Hatching order did not affect levels of either androgen. Our results provide a foundation for future studies of androgen production by nestling owls. © 2010 by the Wilson Ornithological Society. Source


Barrett M.A.,Duke University | Barrett M.A.,University of California at San Francisco | Brown J.L.,Duke University | Junge R.E.,St. Louis Zoo | Yoder A.D.,Duke University
Biological Conservation | Year: 2013

Deforestation and a changing climate threaten the health and survival of lemurs in Madagascar. An important component of lemur health, parasite infection can reduce fitness and survival outcomes. Future lemur parasite richness, abundance and distribution may be highly influenced by climate change. Current knowledge of lemur parasites is narrow in geographic and temporal scope, with sampling at a limited number of sites, and thus far, there have been no attempts to assess the effects of climate change on lemur parasite distributions. We used geospatial tools to predict the distributions of six lemur parasites of high frequency and pathogenic potential. We then assessed how anticipated climate shifts in Madagascar may alter the distributions of these lemur parasites in the future. Under current climate conditions, we found that the focal parasites exhibited widespread potential distributions across Madagascar, covering 12-26% of surface land area and 40-86% of forested area. Our analyses also showed that parasites responded differently to projected climate changes, with shifts ranging from a contraction of current distributions by 7% to an expansion of 60%. A predicted net expansion in parasite distribution may expose naive lemur hosts to new parasites, which could have a profound effect on lemur health. Those parasites with the greatest potential for harmful effects are predicted to experience the largest expansion in range. Predicting these changing distributions will be critical for assessing population health, improving protected area design, preparing for reintroduction efforts and addressing potential parasite risk in lemurs, humans and domestic animals. © 2012 Elsevier Ltd. Source


Shepherdson D.,Oregon Zoo | Lewis K.D.,Oregon Zoo | Carlstead K.,Honolulu Zoo | Bauman J.,St. Louis Zoo | Perrin N.,Oregon Health And Science University
Applied Animal Behaviour Science | Year: 2013

Polar bears (Ursus maritimus) are known to exhibit repetitive pacing behaviors, usually described as stereotypic, in zoo environments. However, little quantitative information exists about the prevalence of pacing in the zoo population. Similarly, large, multi-institutional studies conducted to determine the relationship between stereotypic behavior in zoo polar bears and environmental/husbandry variables using corticoids as a measure of stress are lacking. The study reported here includes data from 55 bears housed in 20 North American zoos. Individual and zoo characteristics were collected and behavior and fecal glucocorticoid metabolites (FGM) were measured over a one-year period. Using an epidemiological approach, individual and facility level multiple linear regression models were constructed to determine the nature, strength and significance of environmental/husbandry variables and temperament (measured using a standardized novel object behavior test) on stereotypic pacing and FGM. We found zoo polar bears performed stereotypic pacing behavior during 14% of the day; the proportion rose to 22% when expressed as a percentage of time engaged in locomotory behavior. However, considerable variation in proportion of stereotypy was observed. Variables associated with reduced pacing at zoos were: enrichment, number of bears in the group, and bears having a view out of their exhibit with a strong suggestion that the existence of a positive reinforcement training program may also be important. Among individuals, bears whose temperament measured high on the "interest" axis (defined in terms of behavior directed toward the novel object) tended to display less stereotypic behavior and those that scored high on the "slow to approach" axis displayed more pacing. We found higher FGM levels were associated with higher proportions of stereotypic pacing, lower levels of the temperament variable "interest" and smaller dry land exhibit area. These results support other studies suggesting polar bears are particularly prone to stereotypic pacing behavior in zoos and that there is a link between stress (measured as FGM) and pacing in zoo polar bears. These findings also suggest that some easily available tools, namely environmental enrichment and possibly positive reinforcement training, can effectively reduce the incidence of these behaviors. Exhibit designers should take note that providing bears with a view out of their exhibit and larger land areas are associated with both behavioral and physiological benefits. Finally, certain temperaments are associated with elevated levels of both stereotypic behavior and corticoids. This information may provide a tool for proactively identifying the individuals most likely to develop pacing behaviors and providing appropriately enhanced care before the behavior becomes established. © 2013 Elsevier B.V. Source


Junge R.E.,St. Louis Zoo | Barrett M.A.,Duke University | Yoder A.D.,Duke University
American Journal of Primatology | Year: 2011

Anthropogenic habitat disturbance impairs ecosystem health by fragmenting forested areas, introducing environmental contamination, and reducing the quality of habitat resources. The effect of this disturbance on wildlife health is of particular concern in Madagascar, one of the world's biodiversity hotspots, where anthropogenic pressures on the environment remain high. Despite the conservation importance of threatened lemur populations in Madagascar, few data exist on the effects of anthropogenic disturbance on lemur health. To examine these impacts, indri (Indri indri) populations were evaluated from two forest reserves that differ in their exposure to anthropogenic disturbance. We compared the health status of 36 indri individuals from two sites: one population from a protected, undisturbed area of lowland evergreen humid forest and the other population from a reserve exposed to frequent tourism and forest degradation. Comparison of indri health parameters between sites suggests an impact of anthropogenic disturbance, including significant differences in leukocyte count and differential, 12 serum parameters, 6 trace minerals, and a higher diversity of parasites, with a significant difference in the presence of the louse, Trichophilopterus babakotophilus. These data suggest that indri living in disturbed forests may experience physiological changes and increased susceptibility to parasitism, which may ultimately impair reproductive success and survival. © 2011 Wiley-Liss, Inc. Source

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