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Reis DJ, Schneider AL, King SE, Forster JE, Bahraini NH. Delivery of bright light therapy within the Veterans Health Administration. J Affect Disord 2024; 349:1-7. [PMID: 38154586 DOI: 10.1016/j.jad.2023.12.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 11/28/2023] [Accepted: 12/23/2023] [Indexed: 12/30/2023]
Abstract
BACKGROUND Bright light therapy (BLT) is efficacious for seasonal and non-seasonal depression. However, the current state of BLT use in practice is unknown, impeding efforts to identify and address utilization gaps. This study's objective was to investigate BLT delivery in a nationwide U.S. healthcare system. METHODS This was a retrospective observational study of electronic medical records from all veterans who received outpatient mood disorder-related care in the Veterans Health Administration (VHA) from October 2008 through September 2020. BLT delivery was measured through the placement of light box consults. RESULTS Of the 3,442,826 veterans who received outpatient mood disorder care, only 57,908 (1.68 %) received a light box consult. Consults increased by 548.44 % (99.9 % credible interval: 467.36 %, 638.74 %) over the timeframe and displayed a robust yearly cycle that peaked on either December 21st or December 22nd. Past mental health treatment for a mood disorder was associated with a higher probability of a consult (relative risk = 4.79, 99.9 % CI: 4.21, 5.60). There was low representation related to veteran age, gender, race, and ethnicity. LIMITATIONS No information on patients who declined light boxes or actual light box use following consult placement. CONCLUSIONS Outpatient BLT delivery for mood disorders in the VHA remains low, despite significant growth over the past decade. It also displays a strong seasonal rhythm that peaks on the winter solstice, suggesting a limited focus on seasonal depression and a suboptimal reactive approach to changing sunlight. Overall, there exists ample opportunity for novel implementation efforts aimed at increasing utilization of BLT.
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Affiliation(s)
- Daniel J Reis
- VA Rocky Mountain Mental Illness Research, Education, and Clinical Center for Veteran Suicide Prevention, Aurora, CO, USA; Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Alexandra L Schneider
- VA Rocky Mountain Mental Illness Research, Education, and Clinical Center for Veteran Suicide Prevention, Aurora, CO, USA
| | - Samuel E King
- VA Rocky Mountain Mental Illness Research, Education, and Clinical Center for Veteran Suicide Prevention, Aurora, CO, USA
| | - Jeri E Forster
- VA Rocky Mountain Mental Illness Research, Education, and Clinical Center for Veteran Suicide Prevention, Aurora, CO, USA; Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Nazanin H Bahraini
- VA Rocky Mountain Mental Illness Research, Education, and Clinical Center for Veteran Suicide Prevention, Aurora, CO, USA; Department of Psychiatry, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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2
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Calhoun DM, Curtis J, Hassan C, Johnson PTJ. Putting infection on the map: Using heatmaps to characterise within- and between-host distributions of trematode metacercariae. J Helminthol 2023; 97:e84. [PMID: 37945271 DOI: 10.1017/s0022149x2300069x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The location of parasites within individual hosts is often treated as a static trait, yet many parasite species can occur in multiple locations or organs within their hosts. Here, we apply distributional heat maps to study the within- and between-host infection patterns for four trematodes (Alaria marcianae, Cephalogonimus americanus, Echinostoma spp. and Ribeiroia ondatrae) within the amphibian hosts Pseudacris regilla and two species of Taricha. We developed heatmaps from 71 individual hosts from six locations in California, which illustrate stark differences among parasites both in their primary locations within amphibian hosts as well as their degree of location specificity. While metacercariae (i.e., cysts) of two parasites (C. americanus and A. marcianae) were relative generalists in habitat selection and often occurred throughout the host, two others (R. ondatrae and Echinostoma spp.) were highly localised to a specific organ or organ system. Comparing parasite distributions among these parasite taxa highlighted locations of overlap showing potential areas of interactions, such as the mandibular inner dermis region, chest and throat inner dermis and the tail reabsorption outer epidermis. Additionally, the within-host distribution of R. ondatrae differed between host species, with metacercariae aggregating in the anterior dermis areas of newts, compared with the posterior dermis area in frogs. The ability to measure fine-scale changes or alterations in parasite distributions has the potential to provide further insight about ecological questions concerning habitat preference, resource selection, host pathology and disease control.
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Affiliation(s)
- Dana M Calhoun
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122 CB334, BoulderCO80309, USA
| | - Jamie Curtis
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122 CB334, BoulderCO80309, USA
| | - Clara Hassan
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122 CB334, BoulderCO80309, USA
| | - Pieter T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado, Ramaley N122 CB334, BoulderCO80309, USA
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3
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Koprivnikar J, Thieltges DW, Johnson PTJ. Consumption of trematode parasite infectious stages: from conceptual synthesis to future research agenda. J Helminthol 2023; 97:e33. [PMID: 36971341 DOI: 10.1017/s0022149x23000111] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Given their sheer cumulative biomass and ubiquitous presence, parasites are increasingly recognized as essential components of most food webs. Beyond their influence as consumers of host tissue, many parasites also have free-living infectious stages that may be ingested by non-host organisms, with implications for energy and nutrient transfer, as well as for pathogen transmission and infectious disease dynamics. This has been particularly well-documented for the cercaria free-living stage of digenean trematode parasites within the Phylum Platyhelminthes. Here, we aim to synthesize the current state of knowledge regarding cercariae consumption by examining: (a) approaches for studying cercariae consumption; (b) the range of consumers and trematode prey documented thus far; (c) factors influencing the likelihood of cercariae consumption; (d) consequences of cercariae consumption for individual predators (e.g. their viability as a food source); and (e) implications of cercariae consumption for entire communities and ecosystems (e.g. transmission, nutrient cycling and influences on other prey). We detected 121 unique consumer-by-cercaria combinations that spanned 60 species of consumer and 35 trematode species. Meaningful reductions in transmission were seen for 31 of 36 combinations that considered this; however, separate studies with the same cercaria and consumer sometimes showed different results. Along with addressing knowledge gaps and suggesting future research directions, we highlight how the conceptual and empirical approaches discussed here for consumption of cercariae are relevant for the infectious stages of other parasites and pathogens, illustrating the use of cercariae as a model system to help advance our knowledge regarding the general importance of parasite consumption.
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Affiliation(s)
- J Koprivnikar
- Department of Chemistry and Biology, Toronto Metropolitan University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3
| | - D W Thieltges
- Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, Den Burg, The Netherlands
| | - P T J Johnson
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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4
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Paxton EH, Paxton KL, Kawasaki MT, Gorresen PM, van Rees CB, Underwood JG. Hawaiian waterbird movement across a developed landscape. J Wildl Manage 2022. [DOI: 10.1002/jwmg.22336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Eben H. Paxton
- U.S. Geological Survey Pacific Island Ecosystems Research Center Box 44, Hawaiʻi National Park HI 96718 USA
| | - Kristina L. Paxton
- Hawaiʻi Cooperative Studies Unit University of Hawaiʻi Hilo PO Box 44, Hawaiʻi National Park HI 96718 USA
| | - Martha T. Kawasaki
- Hawaiʻi Cooperative Studies Unit University of Hawaiʻi Hilo PO Box 44, Hawaiʻi National Park HI 96718 USA
| | - P. Marcos Gorresen
- Hawaiʻi Cooperative Studies Unit University of Hawaiʻi Hilo PO Box 44, Hawaiʻi National Park HI 96718 USA
| | - Charles B. van Rees
- Department of Biology Tufts University 200 College Avenue Medford MA 02155 USA
| | - Jared G. Underwood
- Pacific Islands National Wildlife Refuge Complex U.S. Fish and Wildlife Service Honolulu HI 96850 USA
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5
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Factors associated with the periodicity of Loa loa microfilaremia in the Republic of the Congo. Parasit Vectors 2022; 15:417. [DOI: 10.1186/s13071-022-05541-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/02/2022] [Indexed: 11/11/2022] Open
Abstract
Abstract
Background
Loa loa microfilariae circulate in the peripheral blood of human hosts following a diurnal periodicity, with maximal microfilaremia levels generally observed between 10:00 am and 3:00 pm. Few studies have assessed factors potentially associated with this periodicity.
Methods
Microfilaremia data were collected repeatedly between 9:00 am and 8:00 pm from 13 individuals in the Republic of the Congo. Using local polynomial regression (LOESS), we determined the best models representing the dynamics of microfilaremia over this period. In a second step, using cosinor models, we evaluated the influence of sex, age, and body temperature on the periodicity of L. loa microfilaremia in blood.
Results
All subjects reached their maximum microfilaremia between 10:00 am and 4:00 pm. Individual microfilaremia showed different patterns between individuals, and some clearly showed multiple peaks within a day. LOESS provided a good fit to the observed data. Without adjustment, the maximum microfilarial density was reached around 11:00 am. Adjustment revealed three distinct modes of microfilaremia, occurring around 10:00 am, 1:00 pm, and 4:00 pm. Cosinor models also provided good fit to our data. After adjustment on body temperature, the L. loa microfilaremia fluctuation amplitude decreased significantly from 1684.8 to 310.6 microfilariae(mf)/ml and the predicted peak was estimated at 12:02 pm.
Conclusions
We characterized the periodicity of L. loa microfilaremia mathematically with two different approaches: cosinor models and LOESS regression. Both models suggest that body temperature plays a role in the variation in microfilaremia within a day. Further studies are needed to identify individual co-factors affecting microfilaremia.
Graphical Abstract
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Anderson AM, Friis C, Gratto-Trevor CL, Harris CM, Love OP, Morrison RIG, Prosser SWJ, Nol E, Smith PA. Drought at a coastal wetland affects refuelling and migration strategies of shorebirds. Oecologia 2021; 197:661-674. [PMID: 34657196 PMCID: PMC8585834 DOI: 10.1007/s00442-021-05047-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 09/23/2021] [Indexed: 11/26/2022]
Abstract
Droughts can affect invertebrate communities in wetlands, which can have bottom-up effects on the condition and survival of top predators. Shorebirds, key predators at coastal wetlands, have experienced widespread population declines and could be negatively affected by droughts. We explored, in detail, the effects of drought on multiple aspects of shorebird stopover and migration ecology by contrasting a year with average wet/dry conditions (2016) with a year with moderate drought (2017) at a major subarctic stopover site on southbound migration. We also examined the effects of drought on shorebird body mass during stopover across 14 years (historical: 1974–1982 and present-day: 2014–2018). For the detailed comparison of two years, in the year with moderate drought we documented lower invertebrate abundance at some sites, higher prey family richness in shorebird faecal samples, lower shorebird refuelling rates, shorter stopover durations for juveniles, and, for most species, a higher probability of making a subsequent stopover in North America after departing the subarctic, compared to the year with average wet/dry conditions. In the 14-year dataset, shorebird body mass tended to be lower in drier years. We show that even short-term, moderate drought conditions can negatively affect shorebird refuelling performance at coastal wetlands, which may carry-over to affect subsequent stopover decisions. Given shorebird population declines and predicted changes in the severity and duration of droughts with climate change, researchers should prioritize a better understanding of how droughts affect shorebird refuelling performance and survival.
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Affiliation(s)
- Alexandra M Anderson
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Canada.
| | - Christian Friis
- Canadian Wildlife Service, Environment and Climate Change Canada, Toronto, Canada
| | - Cheri L Gratto-Trevor
- Prairie and Northern Wildlife Research Centre, Environment and Climate Change Canada, Saskatoon, Canada
| | | | - Oliver P Love
- Department of Integrative Biology, University of Windsor, Windsor, Canada
| | - R I Guy Morrison
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Canada
| | - Sean W J Prosser
- Center for Biodiversity Genomics, University of Guelph, Guelph, Canada
| | - Erica Nol
- Department of Biology, Trent University, Peterborough, Canada
| | - Paul A Smith
- National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, Canada
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Falendysz EA, Calhoun DM, Smith CA, Sleeman JM. Outside the Box: Working With Wildlife in Biocontainment. ILAR J 2021; 61:72-85. [PMID: 34428796 DOI: 10.1093/ilar/ilab025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 06/02/2021] [Indexed: 12/11/2022] Open
Abstract
Research with captive wildlife in Animal Biosafety Level 2 (ABSL2) and 3 (ABSL3) facilities is becoming increasingly necessary as emerging and re-emerging diseases involving wildlife have increasing impacts on human, animal, and environmental health. Utilizing wildlife species in a research facility often requires outside the box thinking with specialized knowledge, practices, facilities, and equipment. The USGS National Wildlife Health Center (NWHC) houses an ABSL3 facility dedicated to understanding wildlife diseases and developing tools to mitigate their impacts on animal and human health. This review presents considerations for utilizing captive wildlife for infectious disease studies, including, husbandry, animal welfare, veterinary care, and biosafety. Examples are drawn from primary literature review and collective 40-year experience of the NWHC. Working with wildlife in ABSL2 and ABSL3 facilities differs from laboratory animals in that typical laboratory housing systems, husbandry practices, and biosafety practices are not designed for work with wildlife. This requires thoughtful adaptation of standard equipment and practices, invention of customized solutions and development of appropriate enrichment plans using the natural history of the species and the microbiological characteristics of introduced and native pathogens. Ultimately, this task requires critical risk assessment, understanding of the physical and psychological needs of diverse species, creativity, innovation, and flexibility. Finally, continual reassessment and improvement are imperative in this constantly changing specialty area of infectious disease and environmental hazard research.
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Affiliation(s)
- Elizabeth A Falendysz
- US Geological Survey, National Wildlife Health Center in Madison, Madison, Wisconsin, USA
| | - Dana M Calhoun
- Department of EBIO, University of Colorado Boulder, Boulder, Colorado, USA
| | - Carrie A Smith
- US Geological Survey, National Wildlife Health Center in Madison, Madison, Wisconsin, USA
| | - Jonathan M Sleeman
- US Geological Survey, National Wildlife Health Center in Madison, Madison, Wisconsin, USA
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McDevitt-Galles T, Carpenter SA, Koprivnikar J, Johnson PTJ. How predator and parasite size interact to determine consumption of infectious stages. Oecologia 2021; 197:551-564. [PMID: 34405300 DOI: 10.1007/s00442-021-05010-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 08/02/2021] [Indexed: 01/02/2023]
Abstract
Parasites are important players in ecological communities that can shape community structure and influence ecosystem energy flow. Yet beyond their effects on hosts, parasites can also function as an important prey resource for predators. Predators that consume infectious stages in the environment can benefit from a nutrient-rich prey item while concurrently reducing transmission to downstream hosts, highlighting the broad importance of this interaction. Less clear, however, are the specific characteristics of parasites and predators that increase the likelihood of consumption. Here, we determine what combination(s) of predator and parasite morphological traits lead to high parasite consumption. We exposed the infectious stages (cercariae) of five trematode (fluke) taxa to aquatic insect predators with varying foraging strategies and morphologies. Across the 19 predator-parasite combinations tested, damselfly predators in the family Coenagrionidae were, on average, the most effective predators of cercariae, consuming between 13 and 55% of administered cercariae. Large-bodied cercariae of Ribeiroia ondatrae had the highest average vulnerability to predation, with 37-48% of cercariae consumed. The interaction between predator head width and cercariae tail size strongly influenced the probability of consumption: small-bodied predators were the most effective consumers, particularly for larger tailed parasites. Thus, the likelihood of parasite consumption depended strongly on the relative size between predator and parasite. Our study helps establish that predation on free-living parasites largely follows a broader predator-prey framework. This will help to identify which predator and parasite combinations will likely have high consumptive interactions, potentially reducing parasite transmission in natural populations.
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Affiliation(s)
| | - Sara A Carpenter
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
| | - Janet Koprivnikar
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Pieter T J Johnson
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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9
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Smetzer JR, Paxton KL, Paxton EH. Individual and seasonal variation in the movement behavior of two tropical nectarivorous birds. MOVEMENT ECOLOGY 2021; 9:36. [PMID: 34233764 PMCID: PMC8264974 DOI: 10.1186/s40462-021-00275-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Movement of animals directly affects individual fitness, yet fine spatial and temporal resolution movement behavior has been studied in relatively few small species, particularly in the tropics. Nectarivorous Hawaiian honeycreepers are believed to be highly mobile throughout the year, but their fine-scale movement patterns remain unknown. The movement behavior of these crucial pollinators has important implications for forest ecology, and for mortality from avian malaria (Plasmodium relictum), an introduced disease that does not occur in high-elevation forests where Hawaiian honeycreepers primarily breed. METHODS We used an automated radio telemetry network to track the movement of two Hawaiian honeycreeper species, the 'apapane (Himatione sanguinea) and 'i'iwi (Drepanis coccinea). We collected high temporal and spatial resolution data across the annual cycle. We identified movement strategies using a multivariate analysis of movement metrics and assessed seasonal changes in movement behavior. RESULTS Both species exhibited multiple movement strategies including sedentary, central place foraging, commuting, and nomadism , and these movement strategies occurred simultaneously across the population. We observed a high degree of intraspecific variability at the individual and population level. The timing of the movement strategies corresponded well with regional bloom patterns of 'ōhi'a (Metrosideros polymorpha) the primary nectar source for the focal species. Birds made long-distance flights, including multi-day forays outside the tracking array, but exhibited a high degree of fidelity to a core use area, even in the non-breeding period. Both species visited elevations where avian malaria can occur but exhibited little seasonal change in elevation (< 150 m) and regularly returned to high-elevation roosts at night. CONCLUSIONS This study demonstrates the power of automated telemetry to study complex and fine-scale movement behaviors in rugged tropical environments. Our work reveals a system in which birds can track shifting resources using a diverse set of movement behaviors and can facultatively respond to environmental change. Importantly, fidelity to high-elevation roosting sites minimizes nocturnal exposure to avian malaria for far-ranging individuals and is thus a beneficial behavior that may be under high selection pressure.
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Affiliation(s)
- Jennifer R Smetzer
- Hawai'i Cooperative Studies Unit, University of Hawai'i at Hilo, PO Box 44, Hawai'i National Park, HI, 96718, USA.
| | - Kristina L Paxton
- Hawai'i Cooperative Studies Unit, University of Hawai'i at Hilo, PO Box 44, Hawai'i National Park, HI, 96718, USA
| | - Eben H Paxton
- U.S. Geological Survey Pacific Island Ecosystems Research Center, PO Box 44, Hawai'i National Park, HI, 96718, USA
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Carpenter SA, Vannatta JT, Minchella DJ. Host exposure history and priority effects impact the development and reproduction of a dominant parasite. Int J Parasitol 2021; 51:935-943. [PMID: 34044004 DOI: 10.1016/j.ijpara.2021.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 11/16/2022]
Abstract
Within a single organism, numerous parasites often compete for space and resources. This competition, together with a parasite's ability to locate and successfully establish in a host, can contribute to the distribution and prevalence of parasites. Coinfection with trematodes in snail intermediate hosts is rarely observed in nature, partly due to varying competitive abilities among parasite taxa. Using a freshwater snail host (Biomphalaria glabrata), we studied the ability of a competitively dominant trematode, Echinostoma caproni, to establish and reproduce in a host previously infected with a less competitive trematode species, Schistosoma mansoni. Snails were exposed to S. mansoni and co-exposed to E. caproni either simultaneously or 1 week, 4 weeks, or 6 weeks post S. mansoni exposure. Over the course of infection, we monitored the competitive success of the dominant trematode through infection prevalence, parasite development time, and parasite reproductive output. Infection prevalence of E. caproni did not differ among co-exposed groups or between co-exposed and single exposed groups. However, E. caproni infections in co-exposed hosts took longer to reach maturity when the timing between co-exposures increased. All co-exposed groups had higher E. caproni reproductive output than single exposures. We show that although timing of co-exposure affects the development time of parasite transmission stages, it is not important for successful establishment. Additionally, co-exposure, but not priority effects, increases the reproductive output of the dominant parasite.
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Affiliation(s)
- S A Carpenter
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907, USA.
| | - J T Vannatta
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907, USA
| | - D J Minchella
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907, USA
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Patterns of Sphaeridiotrema pseudoglobulus infection in sympatric and allopatric hosts (Bithynia tentaculata) originating from widely separated sites across the USA. Parasitol Res 2020; 120:187-195. [PMID: 33175265 DOI: 10.1007/s00436-020-06949-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 10/27/2020] [Indexed: 10/23/2022]
Abstract
In circumstances where populations of invasive species occur across variable landscapes, interactions among invaders, their parasites, and the surrounding environment may establish local coevolutionary trajectories for the participants. This can generate variable infection patterns when parasites interact with sympatric versus allopatric hosts. Identifying the potential for such patterns within an invasive-species framework is important for better predicting local infection outcomes and their subsequent impacts on the surrounding native community. To begin addressing this question, we exposed an invasive snail (Bithynia tentaculata) from two widely separated sites across the USA (Wisconsin and Montana) to the digenean parasite, Sphaeridiotrema pseudoglobulus, collected from Wisconsin. Parasite exposures generated high infection prevalences in both sympatric and allopatric snails. Furthermore, host survival, host growth, the proportion of patent snails, and the timing of patency did not differ between sympatric and allopatric combinations. Moreover, passaging parasites through snails of different origins had no effect on transmission success to subsequent hosts in the life cycle. However, the number of parasites emerging from snails and the pattern of their release varied based on snail origin. These latter observations suggest the potential for local adaptation in this system, but subsequent research is required to further substantiate this as a key factor underlying infection patterns in the association between S. pseudoglobulus and B. tentaculata.
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Burger AL, Hartig J, Dierkes PW. Shedding light into the dark: Age and light shape nocturnal activity and sleep behaviour of giraffe. Appl Anim Behav Sci 2020. [DOI: 10.1016/j.applanim.2020.105012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
Abstract
Many temperate freshwater habitats are at risk for contamination by run-off associated with the application of road de-icing salts. Elevated salinity can have various detrimental effects on freshwater organisms, including greater susceptibility to infection by parasites and pathogens. However, to better understand the net effects of road salt exposure on host–parasite dynamics, it is necessary to consider the impacts on free-living parasite infectious stages, such as the motile aquatic cercariae of trematodes. Here, we examined the longevity and activity of cercariae from four different freshwater trematodes (Ribeiroia ondatrae, Echinostoma sp., Cephalogonimus sp. and an unidentified strigeid-type) that were exposed to road salt at five different environmentally relevant concentrations (160, 360, 560, 760 and 960 mg/ml of sodium chloride). Exposure to road salt had minimal detrimental effects, with cercariae activity and survival often greatest at intermediate concentrations. Only the cercariae of Cephalogonimus sp. showed reduced longevity at the highest salt concentration, with those of both R. ondatrae and the unidentified strigeid-type exhibiting diminished activity, indicating interspecific variation in response. Importantly, cercariae seem to be relatively unaffected by salt concentrations known to increase infection susceptibility in some of their hosts. More studies will be needed to examine this potential dichotomy in road salt effects between hosts and trematodes, including influences on parasite infectivity.
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Johnson PTJ, Calhoun DM, Riepe T, McDevitt-Galles T, Koprivnikar J. Community disassembly and disease: realistic-but not randomized-biodiversity losses enhance parasite transmission. Proc Biol Sci 2020; 286:20190260. [PMID: 31039724 DOI: 10.1098/rspb.2019.0260] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Debates over the relationship between biodiversity and disease dynamics underscore the need for a more mechanistic understanding of how changes in host community composition influence parasite transmission. Focusing on interactions between larval amphibians and trematode parasites, we experimentally contrasted the effects of host richness and species composition to identify the individual and joint contributions of both parameters on the infection levels of three trematode species. By combining experimental approaches with field surveys from 147 ponds, we further evaluated how richness effects differed between randomized and realistic patterns of species loss (i.e. community disassembly). Our results indicated that community-level changes in infection levels were owing to host species composition, rather than richness. However, when composition patterns mirrored empirical observations along a natural assembly gradient, each added host species reduced infection success by 12-55%. No such effects occurred when assemblages were randomized. Mechanistically, these patterns were due to non-random host species assembly/disassembly: while highly competent species predominated in low diversity systems, less susceptible hosts became progressively more common as richness increased. These findings highlight the potential for combining information on host traits and assembly patterns to forecast diversity-mediated changes in multi-host disease systems.
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Affiliation(s)
- Pieter T J Johnson
- 1 Ecology and Evolutionary Biology, University of Colorado , Boulder, CO , USA
| | - Dana M Calhoun
- 1 Ecology and Evolutionary Biology, University of Colorado , Boulder, CO , USA
| | - Tawni Riepe
- 1 Ecology and Evolutionary Biology, University of Colorado , Boulder, CO , USA
| | | | - Janet Koprivnikar
- 2 Department of Chemistry and Biology, Ryerson University , Toronto, Ontario , Canada
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Parasite infectious stages provide essential fatty acids and lipid-rich resources to freshwater consumers. Oecologia 2019; 192:477-488. [PMID: 31834514 DOI: 10.1007/s00442-019-04572-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 12/02/2019] [Indexed: 10/25/2022]
Abstract
Free-living parasite infectious stages, such as motile cercariae of trematodes (flatworms), can constitute substantial biomass within aquatic ecosystems and are frequently eaten by various consumers, potentially serving as an important source of nutrients and energy. However, quantitative data on their nutritional value (e.g., essential fatty acids [EFA]) are largely lacking. As EFA are leading indicators of nutritional quality and underpin aquatic ecosystem productivity, we performed fatty acid (FA) analysis on an aggregate of ~ 30,000 cercariae of the freshwater trematode, Ribeiroia ondatrae. Individual cercariae contained 15 ng of total FA, and considerable quantities of EFA, including eicosapentaenoic (EPA, at 0.79 ng cercaria-1) and docosahexaenoic (DHA, at 0.01 ng cercaria-1) acids. We estimated annual EFA production by R. ondatrae cercariae for a series of ponds in California to be 40.4-337.0 μg m-2 yr-1 for EPA and 0.7-6.2 μg m-2 yr-1 for DHA. To investigate viability of cercariae as prey, we also compared growth and FA profiles of dragonfly larvae (naiads of Leucorrhinia intacta) fed equivalent masses of either R. ondatrae or zooplankton (Daphnia spp.) for 5 weeks. Naiads raised on the two diets grew equally well, with no significant differences found in their EFA profiles. While zooplankton are widely recognized as a vital source of energy, and an important conduit for the movement of EFA between algae and higher trophic levels, we suggest a similar role for trematode cercariae by 'unlocking' EFA from the benthic environment, highlighting their potential importance as a nutrient source that supports animal health.
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16
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Host circadian rhythms are disrupted during malaria infection in parasite genotype-specific manners. Sci Rep 2019; 9:10905. [PMID: 31358780 PMCID: PMC6662749 DOI: 10.1038/s41598-019-47191-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 07/11/2019] [Indexed: 12/19/2022] Open
Abstract
Infection can dramatically alter behavioural and physiological traits as hosts become sick and subsequently return to health. Such “sickness behaviours” include disrupted circadian rhythms in both locomotor activity and body temperature. Host sickness behaviours vary in pathogen species-specific manners but the influence of pathogen intraspecific variation is rarely studied. We examine how infection with the murine malaria parasite, Plasmodium chabaudi, shapes sickness in terms of parasite genotype-specific effects on host circadian rhythms. We reveal that circadian rhythms in host locomotor activity patterns and body temperature become differentially disrupted and in parasite genotype-specific manners. Locomotor activity and body temperature in combination provide more sensitive measures of health than commonly used virulence metrics for malaria (e.g. anaemia). Moreover, patterns of host disruption cannot be explained simply by variation in replication rate across parasite genotypes or the severity of anaemia each parasite genotype causes. It is well known that disruption to circadian rhythms is associated with non-infectious diseases, including cancer, type 2 diabetes, and obesity. Our results reveal that disruption of host circadian rhythms is a genetically variable virulence trait of pathogens with implications for host health and disease tolerance.
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Johnson PTJ, Calhoun DM, Riepe TB, Koprivnikar J. Chance or choice? Understanding parasite selection and infection in multi-host communities. Int J Parasitol 2019; 49:407-415. [PMID: 30894285 DOI: 10.1016/j.ijpara.2018.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/03/2018] [Accepted: 12/06/2018] [Indexed: 01/16/2023]
Abstract
Ongoing debate over the relationship between biodiversity and disease risk underscores the need to develop a more mechanistic understanding of how changes in host community composition influence parasite transmission, particularly in complex communities with multiple hosts. A key challenge involves determining how motile parasites select among potential hosts and the degree to which this process shifts with community composition. Focusing on interactions between larval amphibians and the pathogenic trematode Ribeiroia ondatrae, we designed a novel, large-volume set of choice chambers to assess how the selectivity of free-swimming infectious parasites varied among five host species and in response to changes in assemblage composition (four different permutations). In a second set of trials, cercariae were allowed to contact and infect hosts, allowing comparison of host-parasite encounter rates (parasite choice) with infection outcomes (successful infections). Cercariae exhibited consistent preferences for specific host species that were independent of the community context; large-bodied amphibians, such as larval bullfrogs (Rana catesbeiana), exhibited the highest level of parasite attraction. However, because host attractiveness was decoupled from susceptibility to infection, assemblage composition sharply affected both per-host infection as well as total infection (summed among co-occurring hosts). Species such as the non-native R. catesbeiana functioned as epidemiological 'sinks' or dilution hosts, attracting a disproportionate fraction of parasites relative to the number that established successfully, whereas Taricha granulosa and especially Pseudacris regilla supported comparatively more metacercariae relative to cercariae selection. These findings provide a framework for integrating information on parasite preference in combination with more traditional factors such as host competence and density to forecast how changes within complex communities will affect parasite transmission.
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Affiliation(s)
- Pieter T J Johnson
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.
| | - Dana M Calhoun
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Tawni B Riepe
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Janet Koprivnikar
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
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Johnson PTJ, Wilber MQ. Biological and statistical processes jointly drive population aggregation: using host-parasite interactions to understand Taylor's power law. Proc Biol Sci 2018; 284:rspb.2017.1388. [PMID: 28931738 DOI: 10.1098/rspb.2017.1388] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/10/2017] [Indexed: 12/25/2022] Open
Abstract
The macroecological pattern known as Taylor's power law (TPL) represents the pervasive tendency of the variance in population density to increase as a power function of the mean. Despite empirical illustrations in systems ranging from viruses to vertebrates, the biological significance of this relationship continues to be debated. Here we combined collection of a unique dataset involving 11 987 amphibian hosts and 332 684 trematode parasites with experimental measurements of core epidemiological outcomes to explicitly test the contributions of hypothesized biological processes in driving aggregation. After using feasible set theory to account for mechanisms acting indirectly on aggregation and statistical constraints inherent to the data, we detected strongly consistent influences of host and parasite species identity over 7 years of sampling. Incorporation of field-based measurements of host body size, its variance and spatial heterogeneity in host density accounted for host identity effects, while experimental quantification of infection competence (and especially virulence from the 20 most common host-parasite combinations) revealed the role of species-by-environment interactions. By uniting constraint-based theory, controlled experiments and community-based field surveys, we illustrate the joint influences of biological and statistical processes on parasite aggregation and emphasize their importance for understanding population regulation and ecological stability across a range of systems, both infectious and free-living.
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Affiliation(s)
- Pieter T J Johnson
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Mark Q Wilber
- Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
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Reece SE, Prior KF, Mideo N. The Life and Times of Parasites: Rhythms in Strategies for Within-host Survival and Between-host Transmission. J Biol Rhythms 2017; 32:516-533. [PMID: 28845736 PMCID: PMC5734377 DOI: 10.1177/0748730417718904] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Biological rhythms are thought to have evolved to enable organisms to organize their activities according to the earth's predictable cycles, but quantifying the fitness advantages of rhythms is challenging and data revealing their costs and benefits are scarce. More difficult still is explaining why parasites that live exclusively within the bodies of other organisms have biological rhythms. Rhythms exist in the development and traits of parasites, in host immune responses, and in disease susceptibility. This raises the possibility that timing matters for how hosts and parasites interact and, consequently, for the severity and transmission of diseases. Here, we take an evolutionary ecological perspective to examine why parasites exhibit biological rhythms and how their rhythms are regulated. Specifically, we examine the adaptive significance (evolutionary costs and benefits) of rhythms for parasites and explore to what extent interactions between hosts and parasites can drive rhythms in infections. That parasites with altered rhythms can evade the effects of control interventions underscores the urgent need to understand how and why parasites exhibit biological rhythms. Thus, we contend that examining the roles of biological rhythms in disease offers innovative approaches to improve health and opens up a new arena for studying host-parasite (and host-parasite-vector) coevolution.
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Affiliation(s)
- Sarah E. Reece
- Institutes of Evolution, Immunology and Infection Research, University of Edinburgh, Edinburgh, UK
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, UK
| | - Kimberley F. Prior
- Institutes of Evolution, Immunology and Infection Research, University of Edinburgh, Edinburgh, UK
| | - Nicole Mideo
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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