1
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Shaw KE, Cloud RE, Syed R, Civitello DJ. Parasite transmission in size-structured populations. Ecology 2024; 105:e4221. [PMID: 38032549 PMCID: PMC10842837 DOI: 10.1002/ecy.4221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 10/06/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023]
Abstract
Host heterogeneity can affect parasite transmission, but determining underlying traits and incorporating them into transmission models remains challenging. Body size is easily measured and affects numerous ecological interactions, including transmission. In the snail-schistosome system, larger snails have a higher exposure to parasites but lower susceptibility to infection per parasite. We quantified the effect of size-based heterogeneity on population-level transmission by conducting transmission trials in differently size-structured snail populations and competing size-dependent transmission models. Populations with greater proportions of large snails had lower prevalence, and small snails were shielded from infection by co-occurring large conspecifics. Furthermore, a fully dependent transmission model that incorporated body size in both exposure and susceptibility outperformed other candidate models considered. Incorporating traits such as body size, which are affected by and directly affect host ecology, into transmission models could yield insights into natural dynamics and disease mitigation in many systems.
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Affiliation(s)
- Kelsey E Shaw
- Department of Biology, Emory University, Atlanta, Georgia, USA
| | - Rebecca E Cloud
- School of Integrative Biology, University of Illinois, Urbana-Champaign, Illinois, USA
| | - Raeyan Syed
- Department of Biology, Emory University, Atlanta, Georgia, USA
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2
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Starkloff NC, Angelo T, Mahalila MP, Charles J, Kinung'hi S, Civitello DJ. Spatio-temporal variability in transmission risk of human schistosomes and animal trematodes in a seasonally desiccating East African landscape. Proc Biol Sci 2024; 291:20231766. [PMID: 38196367 PMCID: PMC10777146 DOI: 10.1098/rspb.2023.1766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 12/05/2023] [Indexed: 01/11/2024] Open
Abstract
Different populations of hosts and parasites experience distinct seasonality in environmental factors, depending on local-scale biotic and abiotic factors. This can lead to highly heterogeneous disease outcomes across host ranges. Variable seasonality characterizes urogenital schistosomiasis, a neglected tropical disease caused by parasitic trematodes (Schistosoma haematobium). Their intermediate hosts are aquatic Bulinus snails that are highly adapted to extreme rainfall seasonality, undergoing prolonged dormancy yearly. While Bulinus snails have a remarkable capacity for rebounding following dormancy, we investigated the extent to which parasite survival within snails is diminished. We conducted an investigation of seasonal snail schistosome dynamics in 109 ponds of variable ephemerality in Tanzania from August 2021 to July 2022. First, we found that ponds have two synchronized peaks of schistosome infection prevalence and observed cercariae, though of lower magnitude in the fully desiccating than non-desiccating ponds. Second, we evaluated total yearly schistosome prevalence across an ephemerality gradient, finding ponds with intermediate ephemerality to have the highest infection rates. We also investigated dynamics of non-schistosome trematodes, which lacked synonymity with schistosome patterns. We found peak schistosome transmission risk at intermediate pond ephemerality, thus the impacts of anticipated increases in landscape desiccation could result in increases or decreases in transmission risk with global change.
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Affiliation(s)
| | - Teckla Angelo
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
- Nelson Mandela African Institute of Science and Technology, Arusha, Tanzania
| | - Moses P. Mahalila
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
| | - Jenitha Charles
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
| | - Safari Kinung'hi
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
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3
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Ocloo XS, Vazquez-Prokopec GM, Civitello DJ. Mapping current and future habitat suitability of Azolla spp., a biofertilizer for small-scale rice farming in Africa. PLoS One 2023; 18:e0291009. [PMID: 38109403 PMCID: PMC10727437 DOI: 10.1371/journal.pone.0291009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 08/21/2023] [Indexed: 12/20/2023] Open
Abstract
How do we feed the expanding human population without excessive resource depletion or environmental degradation? Recycling and recapturing nutrients could alleviate these challenges, especially if these strategies are robust to climate change. Co-cultivating rice with Azolla spp. in Asia has demonstrated high yields with reduced fertilizer inputs because Azolla fixes atmospheric nitrogen, limits nitrogen volatilization, recaptures and releases other nutrients, and suppresses weeds. While Azolla is distributed in Africa, this approach has not been widely implemented in African rice-farming. Characterizing the suitability of Azolla is critical in evaluating the potential for Azolla-rice in Africa. To do so, we synthesized 189 field and greenhouse studies from around the world that quantified temperature-dependent growth of A. pinnata and A. filiculoides and developed present and future climate suitability maps at the continental scale using mean temperatures under two Representative Concentration Pathways. Currently, most of Africa is suitable for Azolla with slight differences in regional suitability for each species. We project little change in the continent-wide suitability for both species, but anticipate a regional decline, particularly for A. filiculoides in the Sahel. Collaborating with farmers to validate these projections, evaluate the costs and benefits of Azolla-rice, and facilitate adoption of viable strategies can facilitate equitable food systems that also empower African farmers.
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Affiliation(s)
- Xorla S. Ocloo
- Department of African and Black Diaspora Studies, DePaul University, Chicago, IL, United States of America
- Department of Environmental Science and Studies, DePaul University, Chicago, IL, United States of America
| | | | - David J. Civitello
- Department of Biology, Emory University, Atlanta, GA, United States of America
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4
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Vicente-Santos A, Willink B, Nowak K, Civitello DJ, Gillespie TR. Host-pathogen interactions under pressure: A review and meta-analysis of stress-mediated effects on disease dynamics. Ecol Lett 2023; 26:2003-2020. [PMID: 37804128 PMCID: PMC10874615 DOI: 10.1111/ele.14319] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 09/07/2023] [Accepted: 09/12/2023] [Indexed: 10/08/2023]
Abstract
Human activities have increased the intensity and frequency of natural stressors and created novel stressors, altering host-pathogen interactions and changing the risk of emerging infectious diseases. Despite the ubiquity of such anthropogenic impacts, predicting the directionality of outcomes has proven challenging. Here, we conduct a review and meta-analysis to determine the primary mechanisms through which stressors affect host-pathogen interactions and to evaluate the impacts stress has on host fitness (survival and fecundity) and pathogen infectivity (prevalence and intensity). We assessed 891 effect sizes from 71 host species (representing seven taxonomic groups) and 78 parasite taxa from 98 studies. We found that infected and uninfected hosts had similar sensitivity to stressors and that responses varied according to stressor type. Specifically, limited resources compromised host fecundity and decreased pathogen intensity, while abiotic environmental stressors (e.g., temperature and salinity) decreased host survivorship and increased pathogen intensity, and pollution increased mortality but decreased pathogen prevalence. We then used our meta-analysis results to develop susceptible-infected theoretical models to illustrate scenarios where infection rates are expected to increase or decrease in response to resource limitations or environmental stress gradients. Our results carry implications for conservation and disease emergence and reveal areas for future work.
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Affiliation(s)
- Amanda Vicente-Santos
- Population Biology, Ecology, and Evolution Program, Emory University, Atlanta, GA 30322, USA
| | - Beatriz Willink
- Department of Zoology, Stockholm University, Stockholm 106-91, Sweden
- Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore
- School of Biology, University of Costa Rica, San José 11501-2060, Costa Rica
| | - Kacy Nowak
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - David J. Civitello
- Population Biology, Ecology, and Evolution Program, Emory University, Atlanta, GA 30322, USA
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Thomas R. Gillespie
- Population Biology, Ecology, and Evolution Program, Emory University, Atlanta, GA 30322, USA
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
- Department of Environmental Sciences, Emory University, Atlanta, GA 30322, USA
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5
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McMahon TA, Nordheim CL, Detmering SE, Johnson PTJ, Rohr JR, Civitello DJ. Pseudacris regilla metamorphs acquire resistance to Batrachochytrium dendrobatidis after exposure to the killed fungus. Dis Aquat Organ 2023; 155:193-198. [PMID: 37767886 DOI: 10.3354/dao03753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
The pathogenic fungus Batrachochytrium dendrobatidis (Bd) is associated with drastic global amphibian declines. Prophylactic exposure to killed zoospores and the soluble chemicals they produce (Bd metabolites) can induce acquired resistance to Bd in adult Cuban treefrogs Osteopilus septentrionalis. Here, we exposed metamorphic frogs of a second species, the Pacific chorus frog Pseudacris regilla, to one of 2 prophylactic treatments prior to live Bd exposures: killed Bd zoospores with metabolites, killed zoospores alone, or a water control. Prior exposure to killed Bd zoospores with metabolites reduced Bd infection intensity in metamorphic Pacific chorus frogs by 60.4% compared to control frogs. Interestingly, Bd intensity in metamorphs previously exposed to killed zoospores alone did not differ in magnitude relative to the control metamorphs, nor to those treated with killed zoospores plus metabolites. Previous work indicated that Bd metabolites alone can induce acquired resistance in tadpoles, and so these findings together indicate that it is possible that the soluble Bd metabolites may contain immunomodulatory components that drive this resistance phenotype. Our results expand the generality of this prophylaxis work by identifying a second amphibian species (Pacific chorus frog) and an additional amphibian life stage (metamorphic frog) that can acquire resistance to Bd after metabolite exposure. This work increases hopes that a Bd-metabolite prophylaxis might be widely effective across amphibian species and life stages.
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Affiliation(s)
- Taegan A McMahon
- Connecticut College, Department of Biology, New London, Connecticut 06320, USA
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6
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Rohr JR, Sack A, Bakhoum S, Barrett CB, Lopez-Carr D, Chamberlin AJ, Civitello DJ, Diatta C, Doruska MJ, De Leo GA, Haggerty CJE, Jones IJ, Jouanard N, Lund AJ, Ly AT, Ndione RA, Remais JV, Riveau G, Schacht AM, Seck M, Senghor S, Sokolow SH, Wolfe C. A planetary health innovation for disease, food and water challenges in Africa. Nature 2023:10.1038/s41586-023-06313-z. [PMID: 37438520 DOI: 10.1038/s41586-023-06313-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 06/12/2023] [Indexed: 07/14/2023]
Abstract
Many communities in low- and middle-income countries globally lack sustainable, cost-effective and mutually beneficial solutions for infectious disease, food, water and poverty challenges, despite their inherent interdependence1-7. Here we provide support for the hypothesis that agricultural development and fertilizer use in West Africa increase the burden of the parasitic disease schistosomiasis by fuelling the growth of submerged aquatic vegetation that chokes out water access points and serves as habitat for freshwater snails that transmit Schistosoma parasites to more than 200 million people globally8-10. In a cluster randomized controlled trial (ClinicalTrials.gov: NCT03187366) in which we removed invasive submerged vegetation from water points at 8 of 16 villages (that is, clusters), control sites had 1.46 times higher intestinal Schistosoma infection rates in schoolchildren and lower open water access than removal sites. Vegetation removal did not have any detectable long-term adverse effects on local water quality or freshwater biodiversity. In feeding trials, the removed vegetation was as effective as traditional livestock feed but 41 to 179 times cheaper and converting the vegetation to compost provided private crop production and total (public health plus crop production benefits) benefit-to-cost ratios as high as 4.0 and 8.8, respectively. Thus, the approach yielded an economic incentive-with important public health co-benefits-to maintain cleared waterways and return nutrients captured in aquatic plants back to agriculture with promise of breaking poverty-disease traps. To facilitate targeting and scaling of the intervention, we lay the foundation for using remote sensing technology to detect snail habitats. By offering a rare, profitable, win-win approach to addressing food and water access, poverty alleviation, infectious disease control and environmental sustainability, we hope to inspire the interdisciplinary search for planetary health solutions11 to the many and formidable, co-dependent global grand challenges of the twenty-first century.
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Affiliation(s)
- Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA.
| | - Alexandra Sack
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Sidy Bakhoum
- Department of Animal Biology, Université Cheikh Anta Diop, Dakar, Senegal
| | - Christopher B Barrett
- Charles H. Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY, USA
| | - David Lopez-Carr
- Department of Geography, University of California, Santa Barbara, CA, USA
| | - Andrew J Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | | | - Cledor Diatta
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Molly J Doruska
- Charles H. Dyson School of Applied Economics and Management, Cornell University, Ithaca, NY, USA
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Christopher J E Haggerty
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
- Station d'Innovation Aquacole, Saint-Louis, Senegal
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA, USA
- Department of Environmental and Occupational Health, University of Colorado School of Public Health, Anschutz Medical Campus, Aurora, CO, USA
| | - Amadou T Ly
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Raphael A Ndione
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Justin V Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
- Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunité of Lille, Lille, France
| | - Anne-Marie Schacht
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Momy Seck
- Station d'Innovation Aquacole, Saint-Louis, Senegal
| | - Simon Senghor
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Susanne H Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Caitlin Wolfe
- College of Public Health, University of South Florida, Tampa, FL, USA
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7
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Starkloff NC, Angelo T, Mahalila MP, Charles J, Kinung’hi S, Civitello DJ. Spatiotemporal variability in transmission risk of human schistosomes and animal trematodes in a seasonally desiccating East African landscape. bioRxiv 2023:2023.05.25.542103. [PMID: 37292923 PMCID: PMC10245890 DOI: 10.1101/2023.05.25.542103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Different populations of hosts and parasites experience distinct seasonality in environmental factors, depending on local-scale biotic and abiotic factors. This can lead to highly heterogenous disease outcomes across host ranges. Variable seasonality characterizes urogenital schistosomiasis, a neglected tropical disease caused by parasitic trematodes (Schistosoma haematobium). Their intermediate hosts are aquatic Bulinus snails that are highly adapted to extreme rainfall seasonality, undergoing dormancy for up to seven months yearly. While Bulinus snails have a remarkable capacity for rebounding following dormancy, parasite survival within snails is greatly diminished. We conducted a year-round investigation of seasonal snail-schistosome dynamics in 109 ponds of variable ephemerality in Tanzania. First, we found that ponds have two synchronized peaks of schistosome infection prevalence and cercariae release, though of lower magnitude in the fully desiccating ponds than non-desiccating ponds. Second, we evaluated total yearly prevalence across a gradient of an ephemerality, finding ponds with intermediate ephemerality to have the highest infection rates. We also investigated dynamics of non-schistosome trematodes, which lacked synonymity with schistosome patterns. We found peak schistosome transmission risk at intermediate pond ephemerality, thus the impacts of anticipated increases in landscape desiccation could result in increases or decreases in transmission risk with global change.
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Affiliation(s)
| | - Teckla Angelo
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
| | - Moses P. Mahalila
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
| | - Jenitha Charles
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
| | - Safari Kinung’hi
- National Institute of Medical Research Mwanza Center, Mwanza, Tanzania
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8
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Barnett KM, Hilgendorff BA, Civitello DJ, McMahon TA. FUNGAL METABOLITES PROVIDE PRE-EXPOSURE PROTECTION BUT NO POSTEXPOSURE BENEFIT OR HARM AGAINST BATRACHOCHYTRIUM DENDROBATIDIS. J Wildl Dis 2023:492377. [PMID: 37074806 DOI: 10.7589/jwd-d-22-00073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 12/16/2022] [Indexed: 04/20/2023]
Abstract
Disease control tools are needed to mitigate the effect of the fungal pathogen Batrachochytrium dendrobatidis (Bd) on amphibian biodiversity loss. In previous experiments, Bd metabolites (i.e., noninfectious chemicals released by Bd) have been shown to induce partial resistance to Bd when administered before live pathogen exposure and therefore have potential as an intervention strategy to curb Bd outbreaks. In the wild, however, amphibians inhabiting Bd-endemic ecosystems may have already been exposed to or infected with Bd before metabolite administration. It is therefore critical to evaluate the efficacy and safety of Bd metabolites applied postexposure to live Bd. We tested whether Bd metabolites administered postexposure would induce resistance, exacerbate infections, or have no effect. The results confirmed that Bd metabolites applied before pathogen exposure significantly reduced infection intensity, but Bd metabolites applied after pathogen exposure neither protected against nor exacerbated infections. These results reveal the importance of timing the application of Bd metabolite early in the transmission season for Bd-endemic ecosystems and emphasize that Bd metabolite prophylaxis may be a useful tool in captive reintroduction campaigns where Bd threatens the success of re-establishing endangered amphibian populations.
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Affiliation(s)
- K M Barnett
- Department of Biology, Emory University, 1510 Clifton Rd. NE, Atlanta, Georgia 30322, USA
| | - Bridget A Hilgendorff
- Department of Biology, Connecticut College, 270 Mohegan Ave. Pkwy., New London, Connecticut 06320, USA
| | - David J Civitello
- Department of Biology, Emory University, 1510 Clifton Rd. NE, Atlanta, Georgia 30322, USA
| | - Taegan A McMahon
- Department of Biology, Connecticut College, 270 Mohegan Ave. Pkwy., New London, Connecticut 06320, USA
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9
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Desautels DJ, Hartman RB, Weber ME, Jacob N, Sun A, Civitello DJ. Experimental water hyacinth invasion and destructive management increase human schistosome transmission potential. Ecol Appl 2023; 33:e2767. [PMID: 36268601 PMCID: PMC9991957 DOI: 10.1002/eap.2767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 09/09/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
Invasive species cause environmental degradation, decrease biodiversity, and alter ecosystem function. Invasions can also drive changes in vector-borne and zoonotic diseases by altering important traits of wildlife hosts or disease vectors. Managing invasive species can restore biodiversity and ecosystem function, but it may have cascading effects on hosts, parasites, and human risk of infection. Water hyacinth, Eichhornia crassipes, is an extremely detrimental invader in many sites of human schistosome transmission, especially in Lake Victoria, where hyacinth is correlated with high snail abundance and hotspots of human schistosome infection. Hyacinth is often managed via removal or in situ destruction, but the effects of these strategies on snail intermediate hosts and schistosomes are not known. We evaluated the effects of water hyacinth invasion and these management strategies on the dynamics of human schistosomes, Schistosoma mansoni, and snails, Biomphalaria glabrata, in experimental mesocosms over 17 weeks. We hypothesized that hyacinth, which is inedible to snails, would affect snail growth, reproduction, and cercariae production through the balance of its competitive effects on edible algae and its production of edible detritus. We predicted that destruction would create a pulse of edible detrital resources, thereby increasing snail growth, reproduction, and parasite production. Conversely, we predicted that removal would have small or negligible effects on snails and schistosomes, because it would alleviate competition on edible algae without generating a resource pulse. We found that hyacinth invasion suppressed algae, changed the timing of peak snail abundance, and increased total production of human-infectious cercariae ~6-fold relative to uninvaded controls. Hyacinth management had complex effects on algae, snails, and schistosomes. Removal increased algal growth and snail abundance (but not biomass), and slightly reduced schistosome production. In contrast, destruction increased snail biomass (but not abundance), indicating increases in body size. Destruction caused the greatest schistosome production (10-fold more than the control), consistent with evidence that larger snails with greater access to food are most infectious. Our results highlight the dynamic effects of invasion and management on a globally impactful human parasite and its intermediate host. Ultimately, preventing or removing hyacinth invasions would simultaneously benefit human and environmental health outcomes.
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Affiliation(s)
| | | | - Maggie E. Weber
- Department of Biology, Emory University, Atlanta, GA USA 30322
| | - Nathan Jacob
- Department of Biology, Emory University, Atlanta, GA USA 30322
| | - Andrew Sun
- Department of Biology, Emory University, Atlanta, GA USA 30322
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10
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Starkloff NC, Civitello DJ. Cascading impacts of host seasonal adaptation on parasitism. Trends Parasitol 2022; 38:942-949. [PMID: 36088213 PMCID: PMC9588794 DOI: 10.1016/j.pt.2022.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/16/2022] [Accepted: 08/17/2022] [Indexed: 01/13/2023]
Abstract
The persistence of parasite populations through harsh seasonal bouts is often critical to circannual disease outbreaks. Parasites have a diverse repertoire of phenotypes for persistence, ranging from transitioning to a different life stage better suited to within-host dormancy to utilizing weather-hardy structures external to hosts. While these adaptive traits allow parasite species to survive through harsh seasons, it is often at survival rates that threaten population persistence. We argue that these periods of parasite (and vector) population busts could be ideal targets for disease intervention. As climate change portends abbreviated host dormancy and extended transmission periods in many host-parasite systems, it is essential to identify novel pathways to shore up current disease-intervention strategies.
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11
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Starkloff NC, Hartman RB, Civitello DJ. Snail juvenile growth rate as a rapid predictor of the transmission potential of parasitizing human schistosomes. Exp Parasitol 2022; 242:108378. [PMID: 36096192 DOI: 10.1016/j.exppara.2022.108378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/24/2022] [Accepted: 09/06/2022] [Indexed: 11/04/2022]
Abstract
Host and parasite traits that are sensitive to environmental perturbations merit special attention in the mitigation of diseases. While life table experiments allow a practical evaluation of variability of these traits with environmental change, they are cost and resource intensive. Here, we use a model snail host-trematode parasite system to test the efficacy of an expeditious alternative. Rapidly changing host traits (such as juvenile growth rate) can be used as effective predictors of parasite transmission potential across a range of environmental factors. This approach can be applied to anticipate epidemiological changes under diverse environmental scenarios.
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Affiliation(s)
| | - Rachel B Hartman
- Department of Biology, Emory University, Atlanta, GA, 30322, USA
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12
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Nordheim CL, Detmering SE, Civitello DJ, Johnson PTJ, Rohr JR, McMahon TA. Metabolites from the fungal pathogen
Batrachochytrium dendrobatidis
(bd) reduce Bd load in Cuban treefrog tadpoles. J Appl Ecol 2022. [DOI: 10.1111/1365-2664.14242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | - Taegan A. McMahon
- University of Tampa Tampa Florida USA
- Connecticut College New London Connecticut USA
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13
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Koltz AM, Civitello DJ, Becker DJ, Deem SL, Classen AT, Barton B, Brenn-White M, Johnson ZE, Kutz S, Malishev M, Preston DL, Vannatta JT, Penczykowski RM, Ezenwa VO. Sublethal effects of parasitism on ruminants can have cascading consequences for ecosystems. Proc Natl Acad Sci U S A 2022; 119:e2117381119. [PMID: 35533278 PMCID: PMC9171767 DOI: 10.1073/pnas.2117381119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 03/17/2022] [Indexed: 12/29/2022] Open
Abstract
Parasitic infections are common, but how they shape ecosystem-level processes is understudied. Using a mathematical model and meta-analysis, we explored the potential for helminth parasites to trigger trophic cascades through lethal and sublethal effects imposed on herbivorous ruminant hosts after infection. First, using the model, we linked negative effects of parasitic infection on host survival, fecundity, and feeding rate to host and producer biomass. Our model, parameterized with data from a well-documented producer–caribou–helminth system, reveals that even moderate impacts of parasites on host survival, fecundity, or feeding rate can have cascading effects on ruminant host and producer biomass. Second, using meta-analysis, we investigated the links between helminth infections and traits of free-living ruminant hosts in nature. We found that helminth infections tend to exert negative but sublethal effects on ruminant hosts. Specifically, infection significantly reduces host feeding rates, body mass, and body condition but has weak and highly variable effects on survival and fecundity. Together, these findings suggest that while helminth parasites can trigger trophic cascades through multiple mechanisms, overlooked sublethal effects on nonreproductive traits likely dominate their impacts on ecosystems. In particular, by reducing ruminant herbivory, pervasive helminth infections may contribute to a greener world.
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Affiliation(s)
- Amanda M. Koltz
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130
| | | | | | - Sharon L. Deem
- Saint Louis Zoo Institute for Conservation Medicine, Saint Louis, MO 63110
| | - Aimée T. Classen
- Ecology and Evolutionary Biology Department, University of Michigan, Ann Arbor, MI 48109
| | - Brandon Barton
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Maris Brenn-White
- Saint Louis Zoo Institute for Conservation Medicine, Saint Louis, MO 63110
| | - Zoë E. Johnson
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762
| | - Susan Kutz
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | | | - Daniel L. Preston
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO 80523
| | - J. Trevor Vannatta
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907
| | | | - Vanessa O. Ezenwa
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511
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14
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Desautels DJ, Hartman RB, Shaw KE, Maduraiveeran S, Civitello DJ. Divergent effects of invasive macrophytes on population dynamics of a snail intermediate host of Schistosoma Mansoni. Acta Trop 2022; 225:106226. [PMID: 34752781 DOI: 10.1016/j.actatropica.2021.106226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 11/24/2022]
Abstract
Vectors and intermediate hosts of globally impactful human parasites are sensitive to changes in the ecological communities in which they are embedded. Sites of endemic transmission of human schistosome can also be invaded by nonnative species, especially aquatic plants (macrophytes). We tested the effects on macrophyte invasions on experiment snail and schistosome populations created in 100 L mesocosm tanks. We established macrophyte-free mesocosms and those containing one of four widespread macrophyte species that are inedible to snails (duckweed, hornwort, water lettuce, or water hyacinth) and then tracked edible resources (periphyton algae) and the abundance, reproduction, and infection of snail intermediate hosts for 16 weeks. We predicted that the three floating macrophytes would reduce periphyton, thereby reducing snail reproduction, abundance, and infections. In contrast, we predicted that hornwort, which is submerged and provides substrate for periphyton growth, would increase snail reproduction and abundance. As predicted, all floating macrophytes decreased periphyton, but only water hyacinth significantly decreased snail reproduction and abundance. Snail abundance increased significantly only with water lettuce. We hypothesize that this unanticipated increase in snails occurred because water lettuce produced abundant and/or high quality detritus, subsidizing snails despite low periphyton availability. Unfortunately, we detected too few infections to analyze. Aquatic macrophytes exert strong species-specific effects on snail populations. Therefore, efforts to manage invasive plants in endemic sites should evaluate changes in resources, snails, and transmission potential. We recommend caution with management efforts that produce large amounts of detritus, which might stimulate snail populations and therefore risk of human exposure.
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15
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Haggerty CJE, Halstead NT, Civitello DJ, Rohr JR. Reducing disease and producing food: Effects of 13 agrochemicals on snail biomass and human schistosomes. J Appl Ecol 2021. [DOI: 10.1111/1365-2664.14087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher J. E. Haggerty
- Department of Biological Sciences Environmental Change Initiative Eck Institute of Global HealthUniversity of Notre Dame Notre Dame IN USA
| | | | | | - Jason R. Rohr
- Department of Biological Sciences Environmental Change Initiative Eck Institute of Global HealthUniversity of Notre Dame Notre Dame IN USA
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16
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Abstract
1. Hosts and their parasites exist within complex ecological communities. However, the role that non-focal community members, species which cannot be infected by a focal pathogen, may play in altering parasite transmission is often only studied in the lens of the "diversity-disease" relationship by focusing on species richness. This approach largely ignores mechanistic species interactions and risks collapsing our understanding of the community ecology of disease down to defining the prominence of "amplification" vs. "dilution" effects. 2. However, non-focal species vary in their traits, densities, and types of interactions with focal hosts and parasites. Therefore, a community ecology approach based on the mechanisms underlying parasite transmission, host harm, and dynamic species interactions may better advance our understanding of parasite transmission in complex communities. 3. Using the concept of the parasite's basic reproductive ratio, R0, as a generalizable framework, we examine several critical mechanisms by which interactions among hosts, parasites, and non-focal species modulate transmission and provide examples from relevant literature. 4. By focusing on the mechanism by which non-focal species impact transmission, we can emphasize the similarities among classic paradigms in the community ecology of disease, gain new insights into parasite invasion and persistence, community traits correlated with disease dilution or amplification, and the feasibility of biocontrol for parasites of conservation, agricultural, or human health concern.
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Affiliation(s)
- KS Shaw
- Department of Biology, Emory University, Atlanta, GA USA 30322
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17
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Rumschlag SL, Roth SA, McMahon TA, Rohr JR, Civitello DJ. Variability in environmental persistence but not per capita transmission rates of the amphibian chytrid fungus leads to differences in host infection prevalence. J Anim Ecol 2021; 91:170-181. [PMID: 34668575 DOI: 10.1111/1365-2656.13612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/27/2021] [Indexed: 11/28/2022]
Abstract
Heterogeneities in infections among host populations may arise through differences in environmental conditions through two mechanisms. First, environmental conditions may alter host exposure to pathogens via effects on survival. Second, environmental conditions may alter host susceptibility, making infection more or less likely if contact between a host and pathogen occurs. Further, host susceptibility might be altered through acquired resistance, which hosts can develop, in some systems, through exposure to dead or decaying pathogens and their metabolites. Environmental conditions may alter the rates of pathogen decomposition, influencing the likelihood of hosts developing acquired resistance. The present study primarily tests how environmental context influences the relative contributions of pathogen survival and per capita transmission on host infection prevalence using the amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) as a model system. Secondarily, we evaluate how environmental context influences the decomposition of Bd because previous studies have shown that dead Bd and its metabolites can illicit acquired resistance in hosts. We conducted Bd survival and infection experiments and then fit models to discern how Bd mortality, decomposition and per capita transmission rates vary among water sources [e.g. artificial spring water (ASW) or water from three ponds]. We found that infection prevalence differed among water sources, which was driven by differences in mortality rates of Bd, rather than differences in per capita transmission rates. Bd mortality rates varied among pond water treatments and were lower in ASW compared to pond water. These results suggest that variation in Bd infection dynamics could be a function of environmental factors in waterbodies that result in differences in exposure of hosts to live Bd. In contrast to the persistence of live Bd, we found that the rates of decomposition of dead Bd did not vary among water sources, which may suggest that exposure of hosts to dead Bd or its metabolites might not commonly vary among nearby sites. Ultimately, a mechanistic understanding of the environmental dependence of free-living pathogens could lead to a deeper understanding of the patterns of outbreak heterogeneity, which could inform surveillance and management strategies.
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Affiliation(s)
- Samantha L Rumschlag
- Department of Biological Sciences, Environmental Change Initiative, and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.,Department of Integrative Biology, University of South Florida, Tampa, FL, USA
| | - Sadie A Roth
- Department of Integrative Biology, University of South Florida, Tampa, FL, USA.,Department of Natural Resources Management, Texas Tech University, Lubbock, TX, USA
| | - Taegan A McMahon
- Department of Biology, University of Tampa, Tampa, FL, USA.,Department of Biology, Connecticut College, New London, CT, USA
| | - Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA.,Department of Integrative Biology, University of South Florida, Tampa, FL, USA
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18
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Barnett KM, Detmering SE, McMahon TA, Civitello DJ. Asymmetric cross-strain protection for amphibians exposed to a fungal-metabolite prophylactic treatment. Biol Lett 2021; 17:20210207. [PMID: 34428958 DOI: 10.1098/rsbl.2021.0207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chytridiomycosis, an infectious disease of amphibians caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), poses an imminent conservation threat. The global spread of Bd has led to mass mortality events in many amphibian species, resulting in at least 90 species' extinctions to date. Exposure to Bd metabolites (i.e. non-infectious antigenic chemicals released by Bd) partially protects frogs during subsequent challenges with live Bd, suggesting its use as a prophylactic treatment and potential vaccine. However, we do not know whether Bd metabolite exposure protects against strains beyond the one used for treatment. To address this knowledge gap, we conducted a 3 × 2 experiment where we exposed adult Cuban treefrogs, Osteopilus septentrionalis, to one of three treatments (Bd metabolites from California-isolated strain JEL-270, Panamá-isolated strain JEL-419, or an artificial spring water control) and then challenged individuals with live Bd from either strain. We found that exposure to Bd metabolites from the California-isolated strain significantly reduced Bd loads of frogs challenged with the live Panamá-isolated strain, but no other treatments were found to confer protective effects. These findings demonstrate asymmetric cross-protection of a Bd metabolite prophylaxis and suggest that work investigating multiple, diverse strains is urgently needed.
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Affiliation(s)
- K M Barnett
- Department of Biology, Emory University, 1510 Clifton Rd NE, Atlanta, GA 30322, USA
| | - S E Detmering
- Department of Biology, University of Tampa, Tampa, FL 33606, USA
| | - T A McMahon
- Department of Biology, University of Tampa, Tampa, FL 33606, USA.,Department of Biology, Connecticut College, New London, CT 06320, USA
| | - D J Civitello
- Department of Biology, Emory University, 1510 Clifton Rd NE, Atlanta, GA 30322, USA
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19
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Civitello DJ, Hartman RB. Size-asymmetric competition among snails disrupts production of human-infectious Schistosoma mansoni cercariae. Ecology 2021; 102:e03383. [PMID: 33950517 PMCID: PMC8249335 DOI: 10.1002/ecy.3383] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/15/2021] [Indexed: 01/17/2023]
Abstract
Parasites can harm hosts and influence populations, communities, and ecosystems. However, parasites are reciprocally affected by population- and community-level dynamics. Understanding feedbacks between infection dynamics and larger-scale epidemiological and ecological processes could improve predictions and reveal novel control methods. We evaluated how exploitative resource competition among hosts, a fundamental aspect of population biology, influences within-host infection dynamics of the widespread human parasite Schistosoma mansoni in its intermediate host, Biomphalaria glabrata. We added size-dependent consumption of shared resources to a parameterized bioenergetics model to predict a priori the growth, parasite production, and survival of an infected focal host coexisting with an uninfected conspecific competitor in an experiment that varied competitor size. The model quantitatively anticipated that competitors disrupt growth and parasite production and that these effects increase with competitor size. Fitting the model to these data improved its match to host survivorship. Thus, resource competition alters infection dynamics, there are strong size asymmetries in these effects, and size-asymmetric resource competition effects on infection dynamics can be accurately predicted by bioenergetics theory. More broadly, this framework can assess parasite transmission and control in other contexts, such as in resource competitive host communities, or in response to eutrophication, food supplementation, or culling.
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Affiliation(s)
- David J. Civitello
- Department of Biology, Emory University, 1510 Clifton Rd NE, Atlanta, GA 30322
| | - Rachel B. Hartman
- Department of Biology, Emory University, 1510 Clifton Rd NE, Atlanta, GA 30322
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20
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Ezenwa VO, Civitello DJ, Classen AT, Barton BT, Becker DJ, Brenn-White M, Deem SL, Kutz S, Malishev M, Penczykowski RM, Preston DL, Vannatta JT, Koltz AM. Response to Charlier et al.: Climate-Disease Feedbacks Mediated by Livestock Methane Emissions Are Plausible. Trends Ecol Evol 2021; 36:578-579. [PMID: 33966920 DOI: 10.1016/j.tree.2021.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 11/19/2022]
Affiliation(s)
- Vanessa O Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
| | | | - Aimée T Classen
- The Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brandon T Barton
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA
| | - Daniel J Becker
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Maris Brenn-White
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO 63110, USA
| | - Sharon L Deem
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO 63110, USA
| | - Susan Kutz
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | | | | | - Daniel L Preston
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - J Trevor Vannatta
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Amanda M Koltz
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
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21
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Schaber KL, Perkins TA, Lloyd AL, Waller LA, Kitron U, Paz-Soldan VA, Elder JP, Rothman AL, Civitello DJ, Elson WH, Morrison AC, Scott TW, Vazquez-Prokopec GM. Disease-driven reduction in human mobility influences human-mosquito contacts and dengue transmission dynamics. PLoS Comput Biol 2021; 17:e1008627. [PMID: 33465065 PMCID: PMC7845972 DOI: 10.1371/journal.pcbi.1008627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 01/29/2021] [Accepted: 12/11/2020] [Indexed: 02/01/2023] Open
Abstract
Heterogeneous exposure to mosquitoes determines an individual’s contribution to vector-borne pathogen transmission. Particularly for dengue virus (DENV), there is a major difficulty in quantifying human-vector contacts due to the unknown coupled effect of key heterogeneities. To test the hypothesis that the reduction of human out-of-home mobility due to dengue illness will significantly influence population-level dynamics and the structure of DENV transmission chains, we extended an existing modeling framework to include social structure, disease-driven mobility reductions, and heterogeneous transmissibility from different infectious groups. Compared to a baseline model, naïve to human pre-symptomatic infectiousness and disease-driven mobility changes, a model including both parameters predicted an increase of 37% in the probability of a DENV outbreak occurring; a model including mobility change alone predicted a 15.5% increase compared to the baseline model. At the individual level, models including mobility change led to a reduction of the importance of out-of-home onward transmission (R, the fraction of secondary cases predicted to be generated by an individual) by symptomatic individuals (up to -62%) at the expense of an increase in the relevance of their home (up to +40%). An individual’s positive contribution to R could be predicted by a GAM including a non-linear interaction between an individual’s biting suitability and the number of mosquitoes in their home (>10 mosquitoes and 0.6 individual attractiveness significantly increased R). We conclude that the complex fabric of social relationships and differential behavioral response to dengue illness cause the fraction of symptomatic DENV infections to concentrate transmission in specific locations, whereas asymptomatic carriers (including individuals in their pre-symptomatic period) move the virus throughout the landscape. Our findings point to the difficulty of focusing vector control interventions reactively on the home of symptomatic individuals, as this approach will fail to contain virus propagation by visitors to their house and asymptomatic carriers. Human mobility patterns can play an integral role in vector-borne disease dynamics by characterizing an individual’s potential contacts with disease-transmitting vectors. Dengue virus is transmitted by a sedentary vector, but human mobility allows individuals to have contact with mosquitoes at their home and other houses they frequent (their activity space). When accounting for the decreased mobility of symptomatic dengue cases in an agent-based simulation model, however, we found a severely diminished role of the activity space in onward transmission. Those who received the majority of their mosquito contacts outside their home experienced decreases in expected bites and onward transmission when mobility changes were accounted for. Onward transmission was driven by a synergistic relationship between the number of mosquitoes in an individual’s home and their biting suitability, where even those with the highest biting suitability would have limited contribution to transmission given a low number of household mosquitoes. Reactive vector control, which often targets symptomatic cases, could be effective for slowing onward transmission from these cases, but will fail to control virus transmission due to the disproportionate contribution of asymptomatic infections.
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Affiliation(s)
- Kathryn L. Schaber
- Program of Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia, United States of America
| | - T. Alex Perkins
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Alun L. Lloyd
- Biomathematics Graduate Program and Department of Mathematics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Lance A. Waller
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Valerie A. Paz-Soldan
- Department of Global Community Health and Behavioral Sciences, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
| | - John P. Elder
- Graduate School of Public Health, San Diego State University, San Diego, California, United States of America
| | - Alan L. Rothman
- Institute for Immunology and Informatics and Department of Cell and Molecular Biology, University of Rhode Island, Providence, Rhode Island, United States of America
| | - David J. Civitello
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - William H. Elson
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Amy C. Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Thomas W. Scott
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Gonzalo M. Vazquez-Prokopec
- Program of Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia, United States of America
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
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22
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Ezenwa VO, Civitello DJ, Barton BT, Becker DJ, Brenn-White M, Classen AT, Deem SL, Johnson ZE, Kutz S, Malishev M, Penczykowski RM, Preston DL, Vannatta JT, Koltz AM. Infectious Diseases, Livestock, and Climate: A Vicious Cycle? Trends Ecol Evol 2020; 35:959-962. [PMID: 33039158 PMCID: PMC7539894 DOI: 10.1016/j.tree.2020.08.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/18/2020] [Accepted: 08/21/2020] [Indexed: 01/29/2023]
Abstract
Ruminant livestock are a significant contributor to global methane emissions. Infectious diseases have the potential to exacerbate these contributions by elevating methane outputs associated with animal production. With the increasing spread of many infectious diseases, the emergence of a vicious climate–livestock–disease cycle is a looming threat.
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Affiliation(s)
- Vanessa O Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30606, USA.
| | | | - Brandon T Barton
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA
| | - Daniel J Becker
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Maris Brenn-White
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO 63110, USA
| | - Aimée T Classen
- The Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor 48109, USA
| | - Sharon L Deem
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO 63110, USA
| | - Zoë E Johnson
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA
| | - Susan Kutz
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | | | | | - Daniel L Preston
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - J Trevor Vannatta
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Amanda M Koltz
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
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23
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Barnett KM, Civitello DJ. Ecological and Evolutionary Challenges for Wildlife Vaccination. Trends Parasitol 2020; 36:970-978. [PMID: 32952060 PMCID: PMC7498468 DOI: 10.1016/j.pt.2020.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 12/13/2022]
Abstract
Wildlife vaccination is of urgent interest to reduce disease-induced extinction and zoonotic spillover events. However, several challenges complicate its application to wildlife. For example, vaccines rarely provide perfect immunity. While some protection may seem better than none, imperfect vaccination can present epidemiological, ecological, and evolutionary challenges. While anti-infection and antitransmission vaccines reduce parasite transmission, antidisease vaccines may undermine herd immunity, select for increased virulence, or promote spillover. These imperfections interact with ecological and logistical constraints that are magnified in wildlife, such as poor control and substantial trait variation within and among species. Ultimately, we recommend approaches such as trait-based vaccination, modeling tools, and methods to assess community- and ecosystem-level vaccine safety to address these concerns and bolster wildlife vaccination campaigns.
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Affiliation(s)
- K M Barnett
- Department of Biology, Emory University, Atlanta, GA 30322, USA.
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24
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Malishev M, Civitello DJ. Modelling how resource competition among snail hosts affects the mollusciciding frequency and intensity needed to control human schistosomes. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Haggerty CJE, Bakhoum S, Civitello DJ, De Leo GA, Jouanard N, Ndione RA, Remais JV, Riveau G, Senghor S, Sokolow SH, Sow S, Wolfe C, Wood CL, Jones I, Chamberlin AJ, Rohr JR. Aquatic macrophytes and macroinvertebrate predators affect densities of snail hosts and local production of schistosome cercariae that cause human schistosomiasis. PLoS Negl Trop Dis 2020; 14:e0008417. [PMID: 32628666 PMCID: PMC7365472 DOI: 10.1371/journal.pntd.0008417] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/16/2020] [Accepted: 05/22/2020] [Indexed: 12/22/2022] Open
Abstract
Background Schistosomiasis is responsible for the second highest burden of disease among neglected tropical diseases globally, with over 90 percent of cases occurring in African regions where drugs to treat the disease are only sporadically available. Additionally, human re-infection after treatment can be a problem where there are high numbers of infected snails in the environment. Recent experiments indicate that aquatic factors, including plants, nutrients, or predators, can influence snail abundance and parasite production within infected snails, both components of human risk. This study investigated how snail host abundance and release of cercariae (the free swimming stage infective to humans) varies at water access sites in an endemic region in Senegal, a setting where human schistosomiasis prevalence is among the highest globally. Methods/Principal findings We collected snail intermediate hosts at 15 random points stratified by three habitat types at 36 water access sites, and counted cercarial production by each snail after transfer to the laboratory on the same day. We found that aquatic vegetation was positively associated with per-capita cercarial release by snails, probably because macrophytes harbor periphyton resources that snails feed upon, and well-fed snails tend to produce more parasites. In contrast, the abundance of aquatic macroinvertebrate snail predators was negatively associated with per-capita cercarial release by snails, probably because of several potential sublethal effects on snails or snail infection, despite a positive association between snail predators and total snail numbers at a site, possibly due to shared habitat usage or prey tracking by the predators. Thus, complex bottom-up and top-down ecological effects in this region plausibly influence the snail shedding rate and thus, total local density of schistosome cercariae. Conclusions/Significance Our study suggests that aquatic macrophytes and snail predators can influence per-capita cercarial production and total abundance of snails. Thus, snail control efforts might benefit by targeting specific snail habitats where parasite production is greatest. In conclusion, a better understanding of top-down and bottom-up ecological factors that regulate densities of cercarial release by snails, rather than solely snail densities or snail infection prevalence, might facilitate improved schistosomiasis control. Over 800 million people are at risk of schistosomiasis and environmental factors that regulate densities of cercariae parasites that infect humans remain poorly understood. We sampled a spatially extensive area at 36 water-access points in northern Senegal, and quantified densities of snail intermediate hosts, snail predators, and aquatic vegetation in each sample, as well as cercariae released from snails after they were brought to the laboratory. We found that the quantity of submerged aquatic vegetation, particularly Ceratophyllum spp., was positively associated with schistosome cercariae released per infected snail, and total potential cercariae released by the collected snails per water access site. In contrast, the abundance of aquatic predators near infected snails (in the same sweep) was negatively associated with the per-capita cercarial release by infected snails, but positively associated with total snail abundance per site. Additionally, snail densities and potential cercarial densities (estimated as the sum of cercariae released by all collected, infected snails at a site) were only weakly correlated, suggesting that snail densities alone might not accurately reflect total potential of those snails to emit schistosome cercariae. Overall, a better understanding of aquatic factors that can influence the production of schistosome cercariae under field conditions, rather than snail host abundance alone, might facilitate improvements in schistosomiasis monitoring and control.
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Affiliation(s)
- Christopher J. E. Haggerty
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Integrative Biology, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
| | | | - David J. Civitello
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Giulio A. De Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Nicolas Jouanard
- Station d'Innovation Aquacole, Saint-Louis, Senegal
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Raphael A. Ndione
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Justin V. Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, California, United States of America
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
- Institut Pasteur de Lille—CIIL, France
| | - Simon Senghor
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Susanne H. Sokolow
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - Souleymane Sow
- Centre de Recherche Biomédicale Espoir pour la Santé, Saint-Louis, Senegal
| | - Caitlin Wolfe
- College of Public Health, University of South Florida, Tampa, Florida, United States of America
| | - Chelsea L. Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
| | - Isabel Jones
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Andrew J. Chamberlin
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Jason R. Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Department of Integrative Biology, University of South Florida, Tampa, Florida, United States of America
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26
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Mendiola SY, Civitello DJ, Gerardo NM. An integrative approach to symbiont-mediated vector control for agricultural pathogens. Curr Opin Insect Sci 2020; 39:57-62. [PMID: 32299043 DOI: 10.1016/j.cois.2020.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
Vector-borne pathogens pose significant threats to agricultural productivity. Methods that exploit associations between insects and their symbiotic microbes, dubbed symbiont-mediated vector control, are emerging as viable alternatives to insecticides for the control of vector-borne agricultural plant pathogens. The development of methods for effective microbial manipulation, such as RNA interference and paratransgenesis, may facilitate symbiont-mediated vector control tactics aimed at either suppressing insect populations or at manipulating vector competence, an insect vector's ability to acquire, harbor, and transmit pathogens. As suppression strategies transition from the laboratory to the field, the need for methods to evaluate their viability and predict their outcomes is apparent. Mathematical models of symbiont impact on agricultural disease can inform the development of symbiont-mediated vector control. We propose an integrative approach, combining theoretical and empirical experiments to identify the best practices for achieving meaningful improvements to crop health and productivity.
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Affiliation(s)
- Sandra Y Mendiola
- Department of Biology, Emory University, O. Wayne Rollins Research Center, 1510 Clifton Rd, Atlanta, GA 30322, USA.
| | - David J Civitello
- Department of Biology, Emory University, O. Wayne Rollins Research Center, 1510 Clifton Rd, Atlanta, GA 30322, USA
| | - Nicole M Gerardo
- Department of Biology, Emory University, O. Wayne Rollins Research Center, 1510 Clifton Rd, Atlanta, GA 30322, USA
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27
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Malishev M, Civitello DJ. Linking Bioenergetics and Parasite Transmission Models Suggests Mismatch Between Snail Host Density and Production of Human Schistosomes. Integr Comp Biol 2020; 59:1243-1252. [PMID: 31120514 DOI: 10.1093/icb/icz058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The consequences of parasite infection for individual hosts depend on key features of host-parasite ecology underpinning parasite growth and immune defense, such as age, sex, resource supply, and environmental stressors. Scaling these features and their underlying mechanisms from the individual host is challenging but necessary, as they shape parasite transmission at the population level. Translating individual-level mechanisms across scales could inherently improve the way we think about feedbacks among parasitism, the mechanisms driving transmission, and the consequences of human impact and disease control efforts. Here, we use individual-based models (IBMs) based on general metabolic theory, Dynamic Energy Budget (DEB) theory, to scale explicit life-history features of individual hosts, such as growth, reproduction, parasite production, and death, to parasite transmission at the population level over a range of resource supplies focusing on the major human parasite, Schistosoma mansoni, and its intermediate host snail, Biomphalaria glabrata. At the individual level, infected hosts produce fewer parasites at lower resources as competition increases. At the population level, our DEB-IBM predicts brief, but intense parasite peaks early during the host growth season when resources are abundant and infected hosts are few. The timing of these peaks challenges the status quo that high densities of infected hosts produce the highest parasite densities. As expected, high resource supply boosts parasite output, but parasite output also peaks at modest to high host background mortality rates, which parallels overcompensation in stage-structured models. Our combined results reveal the crucial role of individual-level physiology in identifying how environmental conditions, time of the year, and key feedbacks within host-parasite ecology interact to define periods of elevated risk. The testable forecasts from this physiologically-explicit epidemiological model can inform disease management to reduce human risk of schistosome infection.
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28
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Smiley Evans T, Shi Z, Boots M, Liu W, Olival KJ, Xiao X, Vandewoude S, Brown H, Chen JL, Civitello DJ, Escobar L, Grohn Y, Li H, Lips K, Liu Q, Lu J, Martínez-López B, Shi J, Shi X, Xu B, Yuan L, Zhu G, Getz WM. Synergistic China-US Ecological Research is Essential for Global Emerging Infectious Disease Preparedness. Ecohealth 2020; 17:160-173. [PMID: 32016718 PMCID: PMC7088356 DOI: 10.1007/s10393-020-01471-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/03/2019] [Accepted: 12/10/2019] [Indexed: 05/14/2023]
Abstract
The risk of a zoonotic pandemic disease threatens hundreds of millions of people. Emerging infectious diseases also threaten livestock and wildlife populations around the world and can lead to devastating economic damages. China and the USA-due to their unparalleled resources, widespread engagement in activities driving emerging infectious diseases and national as well as geopolitical imperatives to contribute to global health security-play an essential role in our understanding of pandemic threats. Critical to efforts to mitigate risk is building upon existing investments in global capacity to develop training and research focused on the ecological factors driving infectious disease spillover from animals to humans. International cooperation, particularly between China and the USA, is essential to fully engage the resources and scientific strengths necessary to add this ecological emphasis to the pandemic preparedness strategy. Here, we review the world's current state of emerging infectious disease preparedness, the ecological and evolutionary knowledge needed to anticipate disease emergence, the roles that China and the USA currently play as sources and solutions to mitigating risk, and the next steps needed to better protect the global community from zoonotic disease.
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Affiliation(s)
- Tierra Smiley Evans
- One Health Institute, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Zhengli Shi
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Michael Boots
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA.
| | - Wenjun Liu
- Key Laboratory of Pathogenic Microbiology and Immunology, Chinese Academy of Sciences, Beijing, China
| | | | - Xiangming Xiao
- Department of Microbiology and Plant Biology, Center for Spatial Analysis, University of Oklahoma, Norman, OK, USA
| | | | - Heidi Brown
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, AZ, USA
| | - Ji-Long Chen
- College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | | | - Luis Escobar
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, USA
| | - Yrjo Grohn
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | | | - Karen Lips
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Qiyoung Liu
- Department of Vector Biology and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jiahai Lu
- One Health Center of Excellence for Research and Training, School of Public Health, Sun Yat-sen University, Guangzhou, China
| | | | - Jishu Shi
- Laboratory of Vaccine Immunology, US-China Center for Animal Health, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
| | - Xiaolu Shi
- Department of Microbiology, Shenzhen Center for Disease Control and Prevention, Shenzhen, China
| | - Biao Xu
- School of Public Health, Fudan University, Shanghai, China
| | - Lihong Yuan
- School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Guoqiang Zhu
- Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Wayne M Getz
- Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, USA.
- School of Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa.
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29
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Sauer EL, Cohen JM, Lajeunesse MJ, McMahon TA, Civitello DJ, Knutie SA, Nguyen K, Roznik EA, Sears BF, Bessler S, Delius BK, Halstead N, Ortega N, Venesky MD, Young S, Rohr JR. A meta-analysis reveals temperature, dose, life stage, and taxonomy influence host susceptibility to a fungal parasite. Ecology 2020; 101:e02979. [PMID: 31960949 DOI: 10.1002/ecy.2979] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 10/25/2019] [Accepted: 12/05/2019] [Indexed: 12/22/2022]
Abstract
Complex ecological relationships, such as host-parasite interactions, are often modeled with laboratory experiments. However, some experimental laboratory conditions, such as temperature or infection dose, are regularly chosen based on convenience or convention, and it is unclear how these decisions systematically affect experimental outcomes. Here, we conducted a meta-analysis of 58 laboratory studies that exposed amphibians to the pathogenic fungus Batrachochytrium dendrobatidis (Bd) to understand better how laboratory temperature, host life stage, infection dose, and host species affect host mortality. We found that host mortality was driven by thermal mismatches: hosts native to cooler environments experienced greater Bd-induced mortality at relatively warm experimental temperatures and vice versa. We also found that Bd dose positively predicted Bd-induced host mortality and that the superfamilies Bufonoidea and Hyloidea were especially susceptible to Bd. Finally, the effect of Bd on host mortality varied across host life stages, with larval amphibians experiencing lower risk of Bd-induced mortality than adults or metamorphs. Metamorphs were especially susceptible and experienced mortality when inoculated with much smaller Bd doses than the average dose used by researchers. Our results suggest that when designing experiments on species interactions, researchers should carefully consider the experimental temperature, inoculum dose, and life stage, and taxonomy of the host species.
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Affiliation(s)
- Erin L Sauer
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA.,Department of Forest and Wildlife Ecology, University of Wisconsin, 1630 Linden Dr., Madison, 53706, Wisconsin, USA
| | - Jeremy M Cohen
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA.,Department of Forest and Wildlife Ecology, University of Wisconsin, 1630 Linden Dr., Madison, 53706, Wisconsin, USA
| | - Marc J Lajeunesse
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA
| | - Taegan A McMahon
- Department of Biology, University of Tampa, 401 W. Kennedy Blvd., Tampa, 33606, Florida, USA
| | - David J Civitello
- Department of Biology, Emory University, 201 Dowman Dr., Atlanta, 30322, Georgia, USA
| | - Sarah A Knutie
- Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Road, Storrs, 06269, Connecticut, USA
| | - Karena Nguyen
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA
| | - Elizabeth A Roznik
- Department of Research and Conservation, Memphis Zoo, 2000 Prentiss Place, Memphis, 38112, Tennessee, USA
| | | | - Scott Bessler
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA
| | - Bryan K Delius
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA
| | - Neal Halstead
- Wildlands Conservation, 15310 Amberly Dr., Suite 250, Tampa, 33647, Florida, USA
| | - Nicole Ortega
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA
| | - Matthew D Venesky
- Department of Biology, Allegheny College, 520 N Main St., Meadville, 16335, Pennsylvania, USA
| | - Suzanne Young
- Environmental Engineering Institute, Ecole polytechnique fédérale de Lausanne (EPFL), Route Cantonale, 1015, Lausanne, Switzerland
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, 4202 East Fowler Ave, Tampa, 33620, Florida, USA.,Department of Biological Science, University of Notre Dame, 100 Galvin Life Science Center, Notre Dame, 46656, Indiana, USA
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30
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Civitello DJ, Baker LH, Maduraiveeran S, Hartman RB. Resource fluctuations inhibit the reproduction and virulence of the human parasite Schistosoma mansoni in its snail intermediate host. Proc Biol Sci 2020; 287:20192446. [PMID: 31964301 DOI: 10.1098/rspb.2019.2446] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Resource availability can powerfully influence host-parasite interactions. However, we currently lack a mechanistic framework to predict how resource fluctuations alter individual infection dynamics. We address this gap with experiments manipulating resource supply and starvation for a human parasite, Schistosoma mansoni, and its snail intermediate host to test a hypothesis derived from mechanistic energy budget theory: resource fluctuations should reduce schistosome reproduction and virulence by inhibiting parasite ingestion of host biomass. Low resource supply caused hosts to remain small, reproduce less and produce fewer human-infectious cercariae. Periodic starvation also inhibited cercarial production and prevented infection-induced castration. The periodic starvation experiment also revealed substantial differences in fit between two bioenergetic model variants, which differ in their representation of host starvation. Simulations using the best-fit parameters of the winning model suggest that schistosome performance substantially declines with resource fluctuations with periods greater than 7 days. These experiments strengthen mechanistic theory, which can be readily scaled up to the population level to understand key feedbacks between resources, host population dynamics, parasitism and control interventions. Integrating resources with other environmental drivers of disease in an explicit bioenergetic framework could ultimately yield mechanistic predictions for many disease systems.
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Affiliation(s)
- David J Civitello
- Department of Biology, Emory University, 1510 Clifton Rd NE, Atlanta, GA 30322, USA
| | - Lucy H Baker
- Department of Biology, Emory University, 1510 Clifton Rd NE, Atlanta, GA 30322, USA
| | | | - Rachel B Hartman
- Department of Biology, Emory University, 1510 Clifton Rd NE, Atlanta, GA 30322, USA
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31
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Rohr JR, Civitello DJ, Halliday FW, Hudson PJ, Lafferty KD, Wood CL, Mordecai EA. Towards common ground in the biodiversity-disease debate. Nat Ecol Evol 2019; 4:24-33. [PMID: 31819238 PMCID: PMC7224049 DOI: 10.1038/s41559-019-1060-6] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/13/2019] [Indexed: 01/16/2023]
Abstract
The disease ecology community has struggled to come to consensus on whether biodiversity reduces or increases infectious disease risk, a question that directly affects policy decisions for biodiversity conservation and public health. Here, we summarize the primary points of contention regarding biodiversity–disease relationships and suggest that vector-borne, generalist wildlife and zoonotic pathogens are the types of parasites most likely to be affected by changes to biodiversity. One synthesis on this topic revealed a positive correlation between biodiversity and human disease burden across countries, but as biodiversity changed over time within these countries, this correlation became weaker and more variable. Another synthesis—a meta-analysis of generally smaller-scale experimental and field studies—revealed a negative correlation between biodiversity and infectious diseases (a dilution effect) in various host taxa. These results raise the question of whether biodiversity–disease relationships are more negative at smaller spatial scales. If so, biodiversity conservation at the appropriate scales might prevent wildlife and zoonotic diseases from increasing in prevalence or becoming problematic (general proactive approaches). Further, protecting natural areas from human incursion should reduce zoonotic disease spillover. By contrast, for some infectious diseases, managing particular species or habitats and targeted biomedical approaches (targeted reactive approaches) might outperform biodiversity conservation as a tool for disease control. Importantly, biodiversity conservation and management need to be considered alongside other disease management options. These suggested guiding principles should provide common ground that can enhance scientific and policy clarity for those interested in simultaneously improving wildlife and human health. There has been intense debate as to whether biodiversity increases or reduces the risk of infectious disease. This Review is the result of researchers from both sides of the debate attempting to reach a consensus.
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Affiliation(s)
- Jason R Rohr
- Department of Biological Sciences, Eck Institute of Global Health, Environmental Change Initiative, University of Notre Dame, Notre Dame, IN, USA.
| | | | - Fletcher W Halliday
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Peter J Hudson
- Center for Infectious Disease Dynamics, Biology Department, The Pennsylvania State University, University Park, PA, USA
| | - Kevin D Lafferty
- Western Ecological Research Center, US Geological Survey, c/o Marine Science Institute, University of California, Santa Barbara, CA, USA
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
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32
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Strauss AT, Hite JL, Civitello DJ, Shocket MS, Cáceres CE, Hall SR. Genotypic variation in parasite avoidance behaviour and other mechanistic, nonlinear components of transmission. Proc Biol Sci 2019; 286:20192164. [PMID: 31744438 DOI: 10.1098/rspb.2019.2164] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Traditional epidemiological models assume that transmission increases proportionally to the density of parasites. However, empirical data frequently contradict this assumption. General yet mechanistic models can explain why transmission depends nonlinearly on parasite density and thereby identify potential defensive strategies of hosts. For example, hosts could decrease their exposure rates at higher parasite densities (via behavioural avoidance) or decrease their per-parasite susceptibility when encountering more parasites (e.g. via stronger immune responses). To illustrate, we fitted mechanistic transmission models to 19 genotypes of Daphnia dentifera hosts over gradients of the trophically acquired parasite, Metschnikowia bicuspidata. Exposure rate (foraging, F) frequently decreased with parasite density (Z), and per-parasite susceptibility (U) frequently decreased with parasite encounters (F × Z). Consequently, infection rates (F × U × Z) often peaked at intermediate parasite densities. Moreover, host genotypes varied substantially in these responses. Exposure rates remained constant for some genotypes but decreased sensitively with parasite density for others (up to 78%). Furthermore, genotypes with more sensitive foraging/exposure also foraged faster in the absence of parasites (suggesting 'fast and sensitive' versus 'slow and steady' strategies). These relationships suggest that high densities of parasites can inhibit transmission by decreasing exposure rates and/or per-parasite susceptibility, and identify several intriguing axes for the evolution of host defence.
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Affiliation(s)
| | - Jessica L Hite
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
| | | | - Marta S Shocket
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
| | - Carla E Cáceres
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Spencer R Hall
- Department of Biology, Indiana University, Bloomington, IN 47401, USA
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33
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Rohr JR, Civitello DJ, Cohen JM, Roznik EA, Sinervo B, Dell AI. Different metrics of thermal acclimation yield similar effects of latitude, acclimation duration, and body mass on acclimation capacities. Glob Chang Biol 2019; 25:e3-e4. [PMID: 30983105 DOI: 10.1111/gcb.14653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 02/24/2019] [Indexed: 06/09/2023]
Affiliation(s)
- Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, University of Notre Dame, Notre Dame, Indiana
- Department of Integrative Biology, University of South Florida, Tampa, Florida
| | | | - Jeremy M Cohen
- Department of Integrative Biology, University of South Florida, Tampa, Florida
| | - Elizabeth A Roznik
- Memphis Zoo, Department of Research and Conservation, Memphis, Tennessee
| | - Barry Sinervo
- Department of Ecology and Evolutionary Biology, University of California at Santa Cruz, Santa Cruz, California
| | - Anthony I Dell
- National Great Rivers Research and Education Centre (NGRREC), Alton, Illinois
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri
- Department of Biology, St. Louis University, St. Louis, Missouri
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34
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Rohr JR, Barrett CB, Civitello DJ, Craft ME, Delius B, DeLeo GA, Hudson PJ, Jouanard N, Nguyen KH, Ostfeld RS, Remais JV, Riveau G, Sokolow SH, Tilman D. Emerging human infectious diseases and the links to global food production. Nat Sustain 2019; 2:445-456. [PMID: 32219187 PMCID: PMC7091874 DOI: 10.1038/s41893-019-0293-3] [Citation(s) in RCA: 211] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 04/17/2019] [Indexed: 05/07/2023]
Abstract
Infectious diseases are emerging globally at an unprecedented rate while global food demand is projected to increase sharply by 2100. Here, we synthesize the pathways by which projected agricultural expansion and intensification will influence human infectious diseases and how human infectious diseases might likewise affect food production and distribution. Feeding 11 billion people will require substantial increases in crop and animal production that will expand agricultural use of antibiotics, water, pesticides and fertilizer, and contact rates between humans and both wild and domestic animals, all with consequences for the emergence and spread of infectious agents. Indeed, our synthesis of the literature suggests that, since 1940, agricultural drivers were associated with >25% of all - and >50% of zoonotic - infectious diseases that emerged in humans, proportions that will likely increase as agriculture expands and intensifies. We identify agricultural and disease management and policy actions, and additional research, needed to address the public health challenge posed by feeding 11 billion people.
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Affiliation(s)
- Jason R. Rohr
- Department of Biological Sciences, Eck Institute for Global Health, and Environmental Change Initiative, University of Notre Dame, Notre Dame, IN USA
- Department of Integrative Biology, University of South Florida, Tampa, FL USA
| | | | | | - Meggan E. Craft
- Department of Veterinary Population Medicine, University of Minnesota, St Paul, MN USA
| | - Bryan Delius
- Department of Integrative Biology, University of South Florida, Tampa, FL USA
| | - Giulio A. DeLeo
- Department of Biology and Woods Institute for the Environment, Hopkins Marine Station, Stanford University, Pacific Grove, CA USA
| | - Peter J. Hudson
- Center for Infectious Disease Dynamics, Pennsylvania State University, College Station, PA USA
| | - Nicolas Jouanard
- Laboratoire de Recherches Biomédicales, Espoir pour la Santé, Saint-Louis, Senegal
| | - Karena H. Nguyen
- Department of Integrative Biology, University of South Florida, Tampa, FL USA
| | | | - Justin V. Remais
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA USA
| | - Gilles Riveau
- Laboratoire de Recherches Biomédicales, Espoir pour la Santé, Saint-Louis, Senegal
| | - Susanne H. Sokolow
- Department of Biology and Woods Institute for the Environment, Hopkins Marine Station, Stanford University, Pacific Grove, CA USA
- Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA USA
| | - David Tilman
- Department of Ecology, Evolution and Behavior, University of Minnesota, St Paul, MN USA
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35
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Cohen JM, Civitello DJ, Venesky MD, McMahon TA, Rohr JR. An interaction between climate change and infectious disease drove widespread amphibian declines. Glob Chang Biol 2019; 25:927-937. [PMID: 30484936 DOI: 10.1111/gcb.14489] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 10/02/2018] [Indexed: 06/09/2023]
Abstract
Climate change might drive species declines by altering species interactions, such as host-parasite interactions. However, few studies have combined experiments, field data, and historical climate records to provide evidence that an interaction between climate change and disease caused any host declines. A recently proposed hypothesis, the thermal mismatch hypothesis, could identify host species that are vulnerable to disease under climate change because it predicts that cool- and warm-adapted hosts should be vulnerable to disease at unusually warm and cool temperatures, respectively. Here, we conduct experiments on Atelopus zeteki, a critically endangered, captively bred frog that prefers relatively cool temperatures, and show that frogs have high pathogen loads and high mortality rates only when exposed to a combination of the pathogenic chytrid fungus (Batrachochytrium dendrobatidis) and high temperatures, as predicted by the thermal mismatch hypothesis. Further, we tested various hypotheses to explain recent declines experienced by species in the amphibian genus Atelopus that are thought to be associated with B. dendrobatidis and reveal that these declines are best explained by the thermal mismatch hypothesis. As in our experiments, only the combination of rapid increases in temperature and infectious disease could account for the patterns of declines, especially in species adapted to relatively cool environments. After combining experiments on declining hosts with spatiotemporal patterns in the field, our findings are consistent with the hypothesis that widespread species declines, including possible extinctions, have been driven by an interaction between increasing temperatures and infectious disease. Moreover, our findings suggest that hosts adapted to relatively cool conditions will be most vulnerable to the combination of increases in mean temperature and emerging infectious diseases.
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Affiliation(s)
- Jeremy M Cohen
- Department of Integrative Biology, University of South Florida, Tampa, Florida
| | | | | | | | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, Florida
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36
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Cohen JM, McMahon TA, Ramsay C, Roznik EA, Sauer EL, Bessler S, Civitello DJ, Delius BK, Halstead N, Knutie SA, Nguyen KH, Ortega N, Sears B, Venesky MD, Young S, Rohr JR. Impacts of thermal mismatches on chytrid fungus
Batrachochytrium dendrobatidis
prevalence are moderated by life stage, body size, elevation and latitude. Ecol Lett 2019; 22:817-825. [DOI: 10.1111/ele.13239] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/04/2018] [Accepted: 12/05/2018] [Indexed: 01/11/2023]
Affiliation(s)
- Jeremy M. Cohen
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Chloe Ramsay
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Erin L. Sauer
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Scott Bessler
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Bryan K. Delius
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Sarah A. Knutie
- Department of Ecology and Evolutionary Biology University of Connecticut Storrs CT USA
| | - Karena H. Nguyen
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Nicole Ortega
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - Brittany Sears
- Department of Biological Sciences University of South Florida St. Petersburg St. Petersburg FL USA
| | | | - Suzanne Young
- Ecole polytechnique fédérale de Lausanne (EPFL) Lausanne Switzerland
| | - Jason R. Rohr
- Department of Integrative Biology University of South Florida Tampa FL USA
- Department of Biological Sciences University of Notre Dame Notre Dame IN USA
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37
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Civitello DJ, Allman BE, Morozumi C, Rohr JR. Assessing the direct and indirect effects of food provisioning and nutrient enrichment on wildlife infectious disease dynamics. Philos Trans R Soc Lond B Biol Sci 2019. [PMID: 29531153 DOI: 10.1098/rstb.2017.0101] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Anthropogenic resource supplementation can shape wildlife disease directly by altering the traits and densities of hosts and parasites or indirectly by stimulating prey, competitor or predator species. We first assess the direct epidemiological consequences of supplementation, highlighting the similarities and differences between food provisioning and two widespread forms of nutrient input: agricultural fertilization and aquatic nutrient enrichment. We then review an aquatic disease system and a general model to assess whether predator and competitor species can enhance or overturn the direct effects of enrichment. All forms of supplementation can directly affect epidemics by increasing host population size or altering parasite production within hosts, but food provisioning is most likely to aggregate hosts and increase parasite transmission. However, if predators or competitors increase in response to supplementation, they could alter resource-fuelled outbreaks in focal hosts. We recommend identifying the traits of hosts, parasites or interacting species that best predict epidemiological responses to supplementation and evaluating the relative importance of these direct and indirect mechanisms. Theory and experiments should examine the timing of behavioural, physiological and demographic changes for realistic, variable scenarios of supplementation. A more integrative view of resource supplementation and wildlife disease could yield broadly applicable disease management strategies.This article is part of the theme issue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'.
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Affiliation(s)
- David J Civitello
- Department of Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA .,Graduate Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, GA 30322, USA
| | - Brent E Allman
- Graduate Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, GA 30322, USA
| | - Connor Morozumi
- Graduate Program in Population Biology, Ecology, and Evolution, Emory University, Atlanta, GA 30322, USA
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA
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Rohr JR, Civitello DJ, Cohen JM, Roznik EA, Sinervo B, Dell AI. The complex drivers of thermal acclimation and breadth in ectotherms. Ecol Lett 2018; 21:1425-1439. [DOI: 10.1111/ele.13107] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/11/2018] [Accepted: 06/05/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Jason R. Rohr
- Department of Integrative Biology University of South Florida Tampa FL 33620 USA
| | - David J. Civitello
- Department of Integrative Biology University of South Florida Tampa FL 33620 USA
- Department of Biology Emory University Atlanta GA 30322 USA
| | - Jeremy M. Cohen
- Department of Integrative Biology University of South Florida Tampa FL 33620 USA
| | - Elizabeth A. Roznik
- Department of Integrative Biology University of South Florida Tampa FL 33620 USA
- Department of Research and Conservation Memphis Zoo Memphis TN 38112 USA
| | - Barry Sinervo
- Department of Ecology and Evolutionary Biology University of California at Santa Cruz Santa Cruz CA 95064 USA
| | - Anthony I. Dell
- National Great Rivers Research and Education Centre (NGRREC) Alton ILUSA
- Department of Biology Washington University in St. Louis St. Louis MO USA
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Civitello DJ, Fatima H, Johnson LR, Nisbet RM, Rohr JR. Bioenergetic theory predicts infection dynamics of human schistosomes in intermediate host snails across ecological gradients. Ecol Lett 2018. [PMID: 29527787 DOI: 10.1111/ele.12937] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epidemiological dynamics depend on the traits of hosts and parasites, but hosts and parasites are heterogeneous entities that exist in dynamic environments. Resource availability is a particularly dynamic and potent environmental driver of within-host infection dynamics (temporal patterns of growth, reproduction, parasite production and survival). We developed, parameterised and validated a model for resource-explicit infection dynamics by incorporating a parasitism module into dynamic energy budget theory. The model mechanistically explained the dynamic multivariate responses of the human parasite Schistosoma mansoni and its intermediate host snail to variation in resources and host density. At the population level, feedbacks mediated by resource competition could create a unimodal relationship between snail density and human risk of exposure to schistosomes. Consequently, weak snail control could backfire if reductions in snail density release remaining hosts from resource competition. If resource competition is strong and relevant to schistosome production in nature, it could inform control strategies.
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Affiliation(s)
- David J Civitello
- Department of Biology, Emory University, 1510 Clifton Rd NE, 30322, Atlanta, GA, USA
| | - Hiba Fatima
- Global Health Institute, Duke University, Durham, NC, USA
| | - Leah R Johnson
- Department of Statistics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Roger M Nisbet
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, UCSB, 93106, Santa Barbara, CA, USA
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, 4202, East Fowler Ave., 33620, Tampa, FL, USA
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40
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Halstead NT, Hoover CM, Arakala A, Civitello DJ, De Leo GA, Gambhir M, Johnson SA, Jouanard N, Loerns KA, McMahon TA, Ndione RA, Nguyen K, Raffel TR, Remais JV, Riveau G, Sokolow SH, Rohr JR. Agrochemicals increase risk of human schistosomiasis by supporting higher densities of intermediate hosts. Nat Commun 2018; 9:837. [PMID: 29483531 PMCID: PMC5826950 DOI: 10.1038/s41467-018-03189-w] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 01/26/2018] [Indexed: 11/09/2022] Open
Abstract
Schistosomiasis is a snail-borne parasitic disease that ranks among the most important water-based diseases of humans in developing countries. Increased prevalence and spread of human schistosomiasis to non-endemic areas has been consistently linked with water resource management related to agricultural expansion. However, the role of agrochemical pollution in human schistosome transmission remains unexplored, despite strong evidence of agrochemicals increasing snail-borne diseases of wildlife and a projected 2- to 5-fold increase in global agrochemical use by 2050. Using a field mesocosm experiment, we show that environmentally relevant concentrations of fertilizer, a herbicide, and an insecticide, individually and as mixtures, increase densities of schistosome-infected snails by increasing the algae snails eat and decreasing densities of snail predators. Epidemiological models indicate that these agrochemical effects can increase transmission of schistosomes. Identifying agricultural practices or agrochemicals that minimize disease risk will be critical to meeting growing food demands while improving human wellbeing.
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Affiliation(s)
- Neal T Halstead
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA.
- Wildlands Conservation, Inc., 15310 Amberly Drive, Suite 250, Tampa, FL, 33647, USA.
| | - Christopher M Hoover
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Arathi Arakala
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, 3800,, Australia
- Department of Mathematical Sciences, RMIT University, GPO Box 2476, Melbourne, 3001, Australia
| | | | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, 93950, USA
- Stanford Woods Institute for the Environment, Stanford University, Stanford, CA, 94305, USA
| | - Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, 3800,, Australia
- IBM Research Australia, Global Services Australia Pvt. Ltd., 60 City Road, Southbank, 3006, Australia
| | - Steve A Johnson
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, 32611, USA
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale Espoir pour la Santé, BP 226, Saint-Louis, Senegal
| | - Kristin A Loerns
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Taegan A McMahon
- Department of Biology, University of Tampa, Tampa, FL, 33606, USA
| | - Raphael A Ndione
- Centre de Recherche Biomédicale Espoir pour la Santé, BP 226, Saint-Louis, Senegal
| | - Karena Nguyen
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Thomas R Raffel
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA
| | - Justin V Remais
- Division of Environmental Health Sciences, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Gilles Riveau
- Centre de Recherche Biomédicale Espoir pour la Santé, BP 226, Saint-Louis, Senegal
- CIIL - Institut Pasteur de Lille, 1 Rue du Professeur Calmette, 59019, Lille, France
| | - Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, 93950, USA
- Stanford Woods Institute for the Environment, Stanford University, Stanford, CA, 94305, USA
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
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Shocket MS, Strauss AT, Hite JL, Šljivar M, Civitello DJ, Duffy MA, Cáceres CE, Hall SR. Temperature Drives Epidemics in a Zooplankton-Fungus Disease System: A Trait-Driven Approach Points to Transmission via Host Foraging. Am Nat 2018; 191:435-451. [PMID: 29570399 DOI: 10.1086/696096] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Climatic warming will likely have idiosyncratic impacts on infectious diseases, causing some to increase while others decrease or shift geographically. A mechanistic framework could better predict these different temperature-disease outcomes. However, such a framework remains challenging to develop, due to the nonlinear and (sometimes) opposing thermal responses of different host and parasite traits and due to the difficulty of validating model predictions with observations and experiments. We address these challenges in a zooplankton-fungus (Daphnia dentifera-Metschnikowia bicuspidata) system. We test the hypothesis that warmer temperatures promote disease spread and produce larger epidemics. In lakes, epidemics that start earlier and warmer in autumn grow much larger. In a mesocosm experiment, warmer temperatures produced larger epidemics. A mechanistic model parameterized with trait assays revealed that this pattern arose primarily from the temperature dependence of transmission rate (β), governed by the increasing foraging (and, hence, parasite exposure) rate of hosts (f). In the trait assays, parasite production seemed sufficiently responsive to shape epidemics as well; however, this trait proved too thermally insensitive in the mesocosm experiment and lake survey to matter much. Thus, in warmer environments, increased foraging of hosts raised transmission rate, yielding bigger epidemics through a potentially general, exposure-based mechanism for ectotherms. This mechanistic approach highlights how a trait-based framework will enhance predictive insight into responses of infectious disease to a warmer world.
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Díaz-Almeyda EM, Prada C, Ohdera AH, Moran H, Civitello DJ, Iglesias-Prieto R, Carlo TA, LaJeunesse TC, Medina M. Intraspecific and interspecific variation in thermotolerance and photoacclimation in Symbiodinium dinoflagellates. Proc Biol Sci 2017; 284:20171767. [PMID: 29212723 PMCID: PMC5740277 DOI: 10.1098/rspb.2017.1767] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/06/2017] [Indexed: 12/31/2022] Open
Abstract
Light and temperature are major drivers in the ecology and biogeography of symbiotic dinoflagellates living in corals and other cnidarians. We examined variations in physiology among 11 strains comprising five species of clade A Symbiodinium We grew cultures at 26°C (control) and 32°C (high temperature) over a duration of 18 days while measuring growth and photochemical efficiency (Fv /Fm ). Responses to thermal stress ranged from susceptible to tolerant across species and strains. Most strains exhibited a decrease in cell densities and Fv /Fm when grown at 32°C. Tolerance to high temperature (T32) was calculated for all strains, ranging from 0 (unable to survive at high temperature) to 1 (able survive at high temperature). There was substantial variation in thermotolerance across species and among strains. One strain had a T32 close to 1, indicating that growth was not reduced at 32°C for only this one strain. To evaluate the combined effect of temperature and light on physiological stress, we selected three strains with different levels of thermotolerance (tolerant, intermediate and susceptible) and grew them under five different light intensities (65, 80, 100, 240 and 443 µmol quanta m-2 s-1) at 26 and 32°C. High irradiance exacerbated the effect of high temperature, particularly in strains from thermally sensitive species. This work further supports the recognition that broad physiological differences exist not only among species within Symbiodinium clades, but also among strains within species demonstrating that thermotolerance varies widely between species and among strains within species.
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Affiliation(s)
- Erika M Díaz-Almeyda
- Department of Biology, The Pennsylvania State University, State College, PA 16801, USA
- Department of Biology, Emory University, Atlanta, GA 30307, USA
| | - C Prada
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - A H Ohdera
- Department of Biology, The Pennsylvania State University, State College, PA 16801, USA
| | - H Moran
- Department of Biology, The Pennsylvania State University, State College, PA 16801, USA
| | - D J Civitello
- Department of Biology, Emory University, Atlanta, GA 30307, USA
| | - R Iglesias-Prieto
- Department of Biology, The Pennsylvania State University, State College, PA 16801, USA
| | - T A Carlo
- Department of Biology, The Pennsylvania State University, State College, PA 16801, USA
| | - T C LaJeunesse
- Department of Biology, The Pennsylvania State University, State College, PA 16801, USA
| | - M Medina
- Department of Biology, The Pennsylvania State University, State College, PA 16801, USA
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43
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Cohen JM, Venesky MD, Sauer EL, Civitello DJ, McMahon TA, Roznik EA, Rohr JR. The thermal mismatch hypothesis explains host susceptibility to an emerging infectious disease. Ecol Lett 2017; 20:184-193. [DOI: 10.1111/ele.12720] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 10/06/2016] [Accepted: 11/17/2016] [Indexed: 01/15/2023]
Affiliation(s)
- Jeremy M. Cohen
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | - Erin L. Sauer
- Department of Integrative Biology University of South Florida Tampa FL USA
| | - David J. Civitello
- Department of Integrative Biology University of South Florida Tampa FL USA
| | | | | | - Jason R. Rohr
- Department of Integrative Biology University of South Florida Tampa FL USA
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44
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Halstead NT, Civitello DJ, Rohr JR. Comparative toxicities of organophosphate and pyrethroid insecticides to aquatic macroarthropods. Chemosphere 2015; 135:265-271. [PMID: 25966044 DOI: 10.1016/j.chemosphere.2015.03.091] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/25/2015] [Accepted: 03/29/2015] [Indexed: 06/04/2023]
Abstract
As agricultural expansion and intensification increase to meet the growing global food demand, so too will insecticide use and thus the risk of non-target effects. Insecticide pollution poses a particular threat to aquatic macroarthropods, which play important functional roles in freshwater ecosystems. Thus, understanding the relative toxicities of insecticides to non-target functional groups is critical for predicting effects on ecosystem functions. We exposed two common macroarthropod predators, the crayfish Procambarus alleni and the water bug Belostoma flumineum, to three insecticides in each of two insecticide classes (three organophosphates: chlorpyrifos, malathion, and terbufos; and three pyrethroids: esfenvalerate, λ-cyhalothrin, and permethrin) to assess their toxicities. We generated 150 simulated environmental exposures using the US EPA Surface Water Contamination Calculator to determine the proportion of estimated peak environmental concentrations (EECs) that exceeded the US EPA level of concern (0.5×LC50) for non-endangered aquatic invertebrates. Organophosphate insecticides generated consistently low-risk exposure scenarios (EECs<0.5×LC50) for both P. alleni and B. flumineum. Pyrethroid exposure scenarios presented consistently high risk (EECs>0.5×LC50) to P. alleni, but not to B. flumineum, where only λ-cyhalothrin produced consistently high-risk exposures. Survival analyses demonstrated that insecticide class accounted for 55.7% and 91.1% of explained variance in P. alleni and B. flumineum survival, respectively. Thus, risk to non-target organisms is well predicted by pesticide class. Identifying insecticides that pose low risk to aquatic macroarthropods might help meet increased demands for food while mitigating against potential negative effects on ecosystem functions.
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Affiliation(s)
- Neal T Halstead
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, United States.
| | - David J Civitello
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, United States.
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620, United States.
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45
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Gervasi SS, Civitello DJ, Kilvitis HJ, Martin LB. The context of host competence: a role for plasticity in host-parasite dynamics. Trends Parasitol 2015; 31:419-25. [PMID: 26048486 PMCID: PMC4567474 DOI: 10.1016/j.pt.2015.05.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/15/2015] [Accepted: 05/05/2015] [Indexed: 12/17/2022]
Abstract
Even apparently similar hosts can respond differently to the same parasites. Some individuals or specific groups of individuals disproportionately affect disease dynamics. Understanding the sources of among-host heterogeneity in the ability to transmit parasites would improve disease management. A major source of host variation might be phenotypic plasticity - the tendency for phenotypes to change across different environments. Plasticity might be as important as, or even more important than, genetic change, especially in light of human modifications of the environment, because it can occur on a more rapid timescale than evolution. We argue that variation in phenotypic plasticity among and within species strongly contributes to epidemiological dynamics when parasites are shared among multiple hosts, which is often the case.
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Affiliation(s)
- Stephanie S Gervasi
- Department of Integrative Biology, University of South Florida, Science Center 110, Tampa, FL 33620, USA.
| | - David J Civitello
- Department of Integrative Biology, University of South Florida, Science Center 110, Tampa, FL 33620, USA
| | - Holly J Kilvitis
- Department of Integrative Biology, University of South Florida, Science Center 110, Tampa, FL 33620, USA
| | - Lynn B Martin
- Department of Integrative Biology, University of South Florida, Science Center 110, Tampa, FL 33620, USA
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46
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Wilson CH, Caughlin TT, Civitello DJ, Flory SL. Combining mesocosm and field experiments to predict invasive plant performance: a hierarchical Bayesian approach. Ecology 2015; 96:1084-92. [PMID: 26230028 DOI: 10.1890/14-0797.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Invasive plant fecundity underlies propagule pressure and ultimately range expansion. Predicting fecundity across large spatial scales, from regions to landscapes, is critical for understanding invasion dynamics and optimizing management. However, to accurately predict fecundity and other demographic processes, improved models that scale individual plant responses to abiotic drivers across heterogeneous environments are needed. Here we combine two experimental data sets to predict fecundity of a widespread and problematic invasive grass over large spatial scales. First, we analyzed seed production as a function of plant biomass in a small-scale mesocosm experiment with manipulated light levels. Then, in a field introduction experiment, we tracked plant performance across 21 common garden sites that differed widely in available light and other factors. We jointly analyzed these data using a Bayesian hierarchical model (BHM) framework to predict fecundity as a function of light in the field. Our analysis reveals that the invasive species is likely to produce sufficient seed to overwhelm establishment resistance, even in deeply shaded environments, and is likely seed-limited across much of its range. Finally, we extend this framework to address the general problem of how to scale up plant demographic processes and analyze the factors that control plant distribution and abundance at large scales.
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47
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Latta LC, Peacock M, Civitello DJ, Dudycha JL, Meik JM, Schaack S. The phenotypic effects of spontaneous mutations in different environments. Am Nat 2015; 185:243-52. [PMID: 25616142 DOI: 10.1086/679501] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Understanding the context dependence of mutation represents the current frontier of mutation research. In particular, understanding how traits vary in their abilities to accrue mutational variation and how the environment influences expression of mutant phenotypes yields insight into evolutionary processes. We conducted phenotypic assays in four environments using a set of Daphnia pulex mutation accumulation lines to examine the context dependence of mutation. Life-history traits accrued mutational variance faster than morphological traits when considered in individual environments. Across environments, the mutational variance in plasticity was also greater for life-history traits than for morphological traits, although this pattern was less robust. In addition, the expression of mutational variance depended on the environment, which resulted in changes in the rank order of genotype performance across environments in some cases. Such cryptic genetic variation resulting from mutation may maintain genetic diversity and allow for rapid adaptation in spatially or temporally variable environments.
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Affiliation(s)
- Leigh C Latta
- Department of Biology, Reed College, Portland, Oregon 97202
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48
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Strauss AT, Civitello DJ, Cáceres CE, Hall SR. Success, failure and ambiguity of the dilution effect among competitors. Ecol Lett 2015; 18:916-26. [PMID: 26119173 DOI: 10.1111/ele.12468] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 02/24/2015] [Accepted: 05/28/2015] [Indexed: 11/29/2022]
Abstract
It remains challenging to predict variation in the magnitude of disease outbreaks. The dilution effect seeks to explain this variation by linking multiple host species to disease transmission. It predicts that disease risk increases for a focal host when host species diversity declines. However, when an increase in species diversity does not reduce disease, we are often unable to diagnose why. Here, we increase mechanistic and predictive clarity of the dilution effect with a general trait-based model of disease transmission in multi-host communities. Then, we parameterise and empirically test our model with a multi-generational case study of planktonic disease. The model-experiment combination shows that hosts that vary in competitive ability (R*) and potential to spread disease (R0 ) can produce three qualitatively disparate outcomes of dilution on disease: the dilution effect can succeed, fail, or be ambiguous/irrelevant.
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Affiliation(s)
| | - David J Civitello
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620, USA
| | - Carla E Cáceres
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Spencer R Hall
- Department of Biology, Indiana University, Bloomington, IN, 47401, USA
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49
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Civitello DJ, Penczykowski RM, Smith AN, Shocket MS, Duffy MA, Hall SR. Resources, key traits and the size of fungal epidemics in Daphnia populations. J Anim Ecol 2015; 84:1010-7. [PMID: 25733032 DOI: 10.1111/1365-2656.12363] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 02/16/2015] [Indexed: 11/30/2022]
Abstract
Parasites can profoundly affect host populations and ecological communities. Thus, it remains critical to identify mechanisms that drive variation in epidemics. Resource availability can drive epidemics via traits of hosts and parasites that govern disease spread. Here, we map resource-trait-epidemic connections to explain variation in fungal outbreaks (Metschnikowia bicuspidata) in a zooplankton host (Daphnia dentifera) among lakes. We predicted epidemics would grow larger in lakes with more phytoplankton via three energetic mechanisms. First, resources should stimulate Daphnia reproduction, potentially elevating host density. Secondly, resources should boost body size of hosts, enhancing exposure to environmentally distributed propagules through size-dependent feeding. Thirdly, resources should fuel parasite reproduction within hosts. To test these predictions, we sampled 12 natural epidemics and tracked edible algae, fungal infection prevalence, body size, fecundity and density of hosts, as well as within-host parasite loads. Epidemics grew larger in lakes with more algal resources. Structural equation modelling revealed that resource availability stimulated all three traits (host fecundity, host size and parasite load). However, only parasite load connected resources to epidemic size. Epidemics grew larger in more dense Daphnia populations, but host density was unrelated to host fecundity (thus breaking its link to resources). Thus, via energetic mechanisms, resource availability can stimulate key trait(s) governing epidemics in nature. A synthetic focus on resources and resource-trait links could yield powerful insights into epidemics.
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Affiliation(s)
- David J Civitello
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | | | - Aimee N Smith
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Marta S Shocket
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Meghan A Duffy
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Spencer R Hall
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
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50
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Civitello DJ, Rohr JR. Disentangling the effects of exposure and susceptibility on transmission of the zoonotic parasite Schistosoma mansoni. J Anim Ecol 2014; 83:1379-86. [PMID: 24702134 DOI: 10.1111/1365-2656.12222] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 03/24/2014] [Indexed: 11/27/2022]
Abstract
For all parasites, transmission is composed of two processes: host contact with parasites ('exposure') and risk of infection given such contact ('susceptibility'). Classic models, such as mass action (density-dependent) transmission, lump these processes together. However, separating these processes could enhance predictions for disease dynamics, especially for free-living parasites. Here, we outline three transmission models that partition exposure and susceptibility. Using data from a study of Schistosoma mansoni (trematode) infections in Biomphalaria glabrata snails, we competed these three models against four alternative models, including the mass action model (which lumps exposure and susceptibility). The models that separately accounted for exposure and susceptibility best predicted prevalence across the density gradients of hosts and parasites, outperforming all other models based on Akaike information criterion. When embedded into a dynamic epidemiological model, the exposure-explicit models all predicted lower equilibrium densities of infected snails and human-infectious cercariae. Thus, population-level epidemiological models that utilize the classic mass action transmission model might overestimate human risk of schistosomiasis. More generally, the presented approach for disentangling exposure and susceptibility can distinguish between behavioural and immunological resistance, identify mechanisms of 'disease dilution' and provide a more complete dissection of drivers of parasite transmission.
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Affiliation(s)
- David J Civitello
- Department of Integrative Biology, University of South Florida, 4202 E Fowler Ave, Tampa, FL, 33620, USA
| | - Jason R Rohr
- Department of Integrative Biology, University of South Florida, 4202 E Fowler Ave, Tampa, FL, 33620, USA
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