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Welsh JE, Markovic M, van der Meer J, Thieltges DW. Non-linear effects of non-host diversity on the removal of free-living infective stages of parasites. Oecologia 2024; 204:339-349. [PMID: 38300256 PMCID: PMC10907414 DOI: 10.1007/s00442-023-05462-2] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 09/26/2023] [Indexed: 02/02/2024]
Abstract
Among the ecological functions and services of biodiversity is the potential buffering of diseases through dilution effects where increased biodiversity results in a reduction in disease risk for humans and wildlife hosts. Whether such effects are a universal phenomenon is still under intense debate and diversity effects are little studied in cases when non-host organisms remove free-living parasite stages during their transmission from one host to the next by consumption or physical obstruction. Here, we investigated non-host diversity effects on the removal of cercarial stages of trematodes, ubiquitous parasites in aquatic ecosystems. In laboratory experiments using response surface designs, varying both diversity and density at same time, we compared three combinations of two non-hosts at four density levels: predatory crabs that actively remove cercariae from the water column via their mouth parts and gills, filter feeding oysters that passively filter cercariae from the water column while not becoming infected themselves, and seaweed which physically obstructs cercariae. The addition of a second non-host did not generally result in increased parasite removal but neutralised, amplified or reduced the parasite removal exerted by the first non-host, depending on the density and non-host combination. These non-linear non-host diversity effects were probably driven by intra- and interspecific interactions and suggest the need to integrate non-host diversity effects in understanding the links between community diversity and infection risk.
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Affiliation(s)
- Jennifer E Welsh
- Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB, Den Burg, The Netherlands
| | - Mirjana Markovic
- Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB, Den Burg, The Netherlands
| | - Jaap van der Meer
- Wageningen Marine Research, Korringaweg 7, 4401 NT, Yerseke, The Netherlands
- Aquaculture and Fisheries Group, Wageningen University and Research, Wageningen, The Netherlands
| | - David W Thieltges
- Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB, Den Burg, The Netherlands.
- Groningen Institute for Evolutionary Life-Sciences, GELIFES, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
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2
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Saraiva GQ. Pool testing with dilution effects and heterogeneous priors. Health Care Manag Sci 2023; 26:651-672. [PMID: 37526758 DOI: 10.1007/s10729-023-09650-7] [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: 06/08/2022] [Accepted: 06/25/2023] [Indexed: 08/02/2023]
Abstract
The Dorfman pooled testing scheme is a process in which individual specimens (e.g., blood, urine, swabs, etc.) are pooled and tested together; if the merged sample tests positive for infection, then each specimen from the pool is tested individually. Through this procedure, laboratories can reduce the expected number of tests required to screen the population, as individual tests are only carried out when the pooled test detects an infection. Several different partitions of the population can be used to form the pools. In this study, we analyze the performance of ordered partitions, those in which subjects with similar probability of infection are pooled together. We derive sufficient conditions under which ordered partitions outperform other types of partitions in terms of minimizing the expected number of tests, the expected number of false negatives, and the expected number of false positive classifications. These sufficient conditions can be easily verified in practical applications once the dilution effect has been estimated. We also propose a measure of equity and present conditions under which this measure is maximized by ordered partitions.
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Affiliation(s)
- Gustavo Quinderé Saraiva
- Business School, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Macul, Santiago, Chile.
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3
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Castel G, Alburkat H, Tatard C, Dutra L, Criado M, Bouilloud M, Pradel J, Sironen T, Charbonnel N. Puumala orthohantavirus circulation in its wild reservoir, the bank vole, during the 2021 outbreak of hemorrhagic fever with renal syndrome in Jura, France. Infect Dis Now 2023; 53:104767. [PMID: 37562571 DOI: 10.1016/j.idnow.2023.104767] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/12/2023]
Abstract
OBJECTIVE A large and unprecedented outbreak of an attenuated form of hemorrhagic fever with renal syndrome called nephropathia epidemica (NE) and caused by Puumala virus (PUUV) occurred in 2021 in the southern Jura Mountains (France) leading to numerous hospitalizations. The aim of this study was to investigate the circulation of PUUV in its animal reservoir at the time of this outbreak. METHODS We conjointly surveyed bank vole relative abundance, small mammal community composition, and PUUV circulation in bank voles (seroprevalence and genetic diversity) in the Jura NE epidemic area, between 2020 and 2022. RESULTS Trapping results showed a higher relative abundance of bank voles in 2021 compared to 2020 and 2022. Extremely high levels of PUUV seroprevalence in bank voles were found at the time of the human NE epidemic with seropositive animals trapped in almost all trap lines as of spring 2021. Genetic analyses of PUUV (S segment) gathered in 2021 at two sampling sites revealed a strong clustering of these strains within the "Jura" clade. No significant genetic variation was detected compared to what was already known to be circulating in the Jura region. CONCLUSION These results underline a need for enhanced monitoring of PUUV circulation in host reservoir populations in NE endemic areas. This would enable the relevant actors to better inform and sensitize the public on this zoonotic risk, and to implement prevention strategies in collaboration with physicians.
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Affiliation(s)
- Guillaume Castel
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Université de Montpellier, France.
| | - Hussein Alburkat
- Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Caroline Tatard
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Université de Montpellier, France
| | - Lara Dutra
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Mathilde Criado
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Université de Montpellier, France
| | - Marie Bouilloud
- CBGP, IRD, INRAE, CIRAD, Institut Agro, Université de Montpellier, France
| | - Julien Pradel
- CBGP, INRAE, CIRAD, IRD, Institut Agro, Université de Montpellier, France
| | - Tarja Sironen
- Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
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Tosa MI, Biel MJ, Graves TA. Bighorn sheep associations: understanding tradeoffs of sociality and implications for disease transmission. PeerJ 2023; 11:e15625. [PMID: 37576510 PMCID: PMC10416771 DOI: 10.7717/peerj.15625] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 06/02/2023] [Indexed: 08/15/2023] Open
Abstract
Sociality directly influences mating success, survival rates, and disease, but ultimately likely evolved for its fitness benefits in a challenging environment. The tradeoffs between the costs and benefits of sociality can operate at multiple scales, resulting in different interpretations of animal behavior. We investigated the influence of intrinsic (e.g., relatedness, age) and extrinsic factors (e.g., land cover type, season) on direct contact (simultaneous GPS locations ≤ 25 m) rates of bighorn sheep (Ovis canadensis) at multiple scales near the Waterton-Glacier International Peace Park. During 2002-2012, male and female bighorn were equipped with GPS collars. Indirect contact (GPS locations ≤ 25 m regardless of time) networks identified two major breaks whereas direct contact networks identified an additional barrier in the population, all of which corresponded with prior disease exposure metrics. More direct contacts occurred between same-sex dyads than female-male dyads and between bighorn groups with overlapping summer home ranges. Direct contacts occurred most often during the winter-spring season when bighorn traveled at low speeds and when an adequate number of bighorn were collared in the area. Direct contact probabilities for all dyad types were inversely related to habitat quality, and differences in contact probability were driven by variables related to survival such as terrain ruggedness, distance to escape terrain, and canopy cover. We provide evidence that probabilities of association are higher when there is greater predation risk and that contact analysis provides valuable information for understanding fitness tradeoffs of sociality and disease transmission potential.
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Affiliation(s)
- Marie I. Tosa
- Northern Rocky Mountain Science Center, U.S. Geological Survey, West Glacier, MT, United States of America
| | - Mark J. Biel
- Glacier National Park, National Park Service, West Glacier, MT, United States of America
| | - Tabitha A. Graves
- Northern Rocky Mountain Science Center, U.S. Geological Survey, West Glacier, MT, United States of America
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Hanthanan Arachchilage K, Hussaini MY, Cogan NG, Cortez MH. Exploring how ecological and epidemiological processes shape multi-host disease dynamics using global sensitivity analysis. J Math Biol 2023; 86:83. [PMID: 37154947 DOI: 10.1007/s00285-023-01912-w] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 12/24/2022] [Accepted: 03/31/2023] [Indexed: 05/10/2023]
Abstract
We use global sensitivity analysis (specifically, Partial Rank Correlation Coefficients) to explore the roles of ecological and epidemiological processes in shaping the temporal dynamics of a parameterized SIR-type model of two host species and an environmentally transmitted pathogen. We compute the sensitivities of disease prevalence in each host species to model parameters. Sensitivity rankings are calculated, interpreted biologically, and contrasted for cases where the pathogen is introduced into a disease-free community and cases where a second host species is introduced into an endemic single-host community. In some cases the magnitudes and dynamics of the sensitivities can be predicted only by knowing the host species' characteristics (i.e., their competitive abilities and disease competence) whereas in other cases they can be predicted by factors independent of the species' characteristics (specifically, intraspecific versus interspecific processes or a species' roles of invader versus resident). For example, when a pathogen is initially introduced into a disease-free community, disease prevalence in both hosts is more sensitive to the burst size of the first host than the second host. In comparison, disease prevalence in each host is more sensitive to its own infection rate than the infection rate of the other host species. In total, this study illustrates that global sensitivity analysis can provide useful insight into how ecological and epidemiological processes shape disease dynamics and how those effects vary across time and system conditions. Our results show that sensitivity analysis can provide quantification and direction when exploring biological hypotheses.
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Affiliation(s)
| | - Mohammed Y Hussaini
- Department of Mathematics, Florida State University, Tallahassee, Fl, 32306, USA
| | - N G Cogan
- Department of Mathematics, Florida State University, Tallahassee, Fl, 32306, USA
| | - Michael H Cortez
- Department of Biological Science, Florida State University, Tallahassee, Fl, 32306, USA.
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Li F, Mai Z, Qiu C, Long L, Hu A, Huang S. Dissemination of antibiotic resistance genes from the Pearl River Estuary to adjacent coastal areas. Mar Environ Res 2023; 188:105978. [PMID: 37087846 DOI: 10.1016/j.marenvres.2023.105978] [Citation(s) in RCA: 1] [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] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/03/2023] [Accepted: 04/08/2023] [Indexed: 05/03/2023]
Abstract
The spread of antibiotic resistance genes (ARGs) is a growing concern over the world's various environments. Coastal environments may receive pollutants from land runoffs via estuaries. However, the impact of ARG contamination from estuarine regions to coastal areas is rarely reported. This study used high-throughput quantitative PCR to examine the diversity and abundance of ARGs in Pearl River Estuary (PRE) and adjacent coastal areas. We found that the distribution of ARGs in seawater exhibited the distance-decay phenomenon from the estuary to coastal areas, while the sediment samples did not exhibit an obvious distribution pattern. The estuarine water was found to be the hotspot of ARGs, with 74 ARG species detected and absolute abundance being 5.93 × 105 copies per mL, on average, while less species and lower abundance of ARGs were detected in coastal waters. Ordination analysis showed that estuarine ARG communities were significantly different from coastal ARG communities for water samples. SourceTracker analysis revealed that ARGs from the estuarine environment contributed only a minor fraction of ARG contamination to downstream coastal areas (1.5%-7.4% for water samples, and 0.7-1.8% for sediment samples), indicating the strong dilution effect of seawater. Mantel tests, redundancy analysis and random forest model analysis identified salinity, nutrients, microbial community structure and mobile genetic elements (MGEs) as important factors influencing ARG distribution. Partial least squares-path model revealed that, among all environmental factors, MGEs directly affected the distribution of ARGs, while other factors indirectly contributed by affecting the MGEs assemblage. Our study provides insight into the dissemination of ARGs from the PRE to adjacent coastal areas.
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Affiliation(s)
- Furun Li
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Huairou, Beijing, 101400, China
| | - Zhimao Mai
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Chen Qiu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Huairou, Beijing, 101400, China
| | - Lijuan Long
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China
| | - Anyi Hu
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
| | - Sijun Huang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.
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7
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Wang YXG, Matson KD, Prins HHT, Xu Y, Huang ZYX, de Boer WF. Risk factors for Lyme disease: A scale-dependent effect of host species diversity and a consistent negative effect of host phylogenetic diversity. Ticks Tick Borne Dis 2023; 14:102073. [PMID: 36345067 DOI: 10.1016/j.ttbdis.2022.102073] [Citation(s) in RCA: 1] [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] [Received: 12/01/2021] [Revised: 10/13/2022] [Accepted: 10/28/2022] [Indexed: 11/06/2022]
Abstract
Biodiversity can influence disease risk. One example of a diversity-disease relationship is the dilution effect, which suggests higher host species diversity (often indexed by species richness) reduces disease risk. While numerous studies support the dilution effect, its generality remains controversial. Most studies of diversity-disease relationships have overlooked the potential importance of phylogenetic diversity. Furthermore, most studies have tested diversity-disease relationships at one spatial scale, even though such relationships are likely scale dependent. Using Lyme disease as a model system, we investigated the effects of host species richness and phylogenetic relatedness on the number of reported Lyme disease cases in humans in the U.S.A. at two spatial scales (the county level and the state level) using piecewise structural equation modelling. We also accounted for relevant climatic and habitat-related factors and tested their correlations with the number of Lyme disease cases. We found that species assemblages with more related species (i.e., host species in the order Rodentia) were associated with more Lyme disease cases in humans. Host species richness correlated negatively with the number of Lyme disease cases at the state level (i.e., a dilution effect), a pattern that might be explained by the higher number of reservoir-incompetent species at high levels of species richness at this larger spatial scale. In contrast, a positive correlation was found between species richness and the number of Lyme disease cases at the county level, where a higher proportion of rodent species was associated with higher levels of species richness, potentially amplifying the disease risk. Our results highlight that analyse at a single spatial scale can miss some impacts of biodiversity on human health. Thus, multi-scale analyses with consideration of host phylogenetic diversity are critical for improving our understanding of diversity-disease relationships.
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Affiliation(s)
- Yingying X G Wang
- Wildlife Ecology and Conservation Group, Wageningen University & Research, 6708 PB Wageningen, Netherlands; Department of Biological and Environmental Science, University of Jyväskylä, FI-40014 Jyväskylä, Finland
| | - Kevin D Matson
- Wildlife Ecology and Conservation Group, Wageningen University & Research, 6708 PB Wageningen, Netherlands
| | - Herbert H T Prins
- Department of Animal Sciences, Wageningen University & Research, 6708 WD Wageningen, Netherlands
| | - Yanjie Xu
- Wildlife Ecology and Conservation Group, Wageningen University & Research, 6708 PB Wageningen, Netherlands; Finnish Museum of Natural History, University of Helsinki, 17, 00014, Finland
| | - Zheng Y X Huang
- College of Life Sciences, Nanjing Normal University, 210046 Nanjing, China.
| | - Willem F de Boer
- Wildlife Ecology and Conservation Group, Wageningen University & Research, 6708 PB Wageningen, Netherlands
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Stanicka A, Cichy A, Bulantová J, Labecka AM, Ćmiel AM, Templin J, Horák P, Żbikowska E. Thinking "outside the box": The effect of nontarget snails in the aquatic community on mollusc-borne diseases. Sci Total Environ 2022; 845:157264. [PMID: 35820526 DOI: 10.1016/j.scitotenv.2022.157264] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
There is a great need to understand the impact of complex communities on the free-living parasite stages that are part of them. This task becomes more complex as nonnative species emerge, changing existing relationships and shaping new interactions in the community. A relevant question would be: Can the coexistence of nontarget snails with the target hosts contribute to trematodasis control? We used field and experimental approaches to investigate nonnative competitor-induced parasite dilution. During a three-year field study, we investigated digenean infection in Lymnaea stagnalis from eight Polish lakes inhabited or uninhabited by Potamopyrgus antipodarum. Additionally, we verified the presence of digenean infections in the populations of P. antipodarum. Moreover, we conducted an experimental infection of L. stagnalis with miracidia of Trichobilharzia szidati under increasing densities of P. antipodarum and aimed to infect P. antipodarum with them separately. The prevalence of avian schistosomes in lymnaeid snails was significantly higher in uninhabited lakes than in lakes inhabited by P. antipodarum. Our study indicates that waters with a higher density of invaders have a lower prevalence of avian schistosomes in lymnaeid hosts. The results of experimental studies confirmed that the presence of high densities of P. antipodarum reduces the probability of target host infection. Both field and experimental studies rule out the role of P. antipodarum as a source of avian schistosome cercariae. Here, a nonnative species was tested as a diluter, which in practice may be harmful to the local environment. This work is not a call for the introduction of nonnative species; it is intended to be a stimulus for researchers to continue searching for natural enemies of parasites because, as our results show, they exist. Finding natural enemies to the most dangerous species of human and animal parasites that will pose no threat to the local environment could be groundbreaking.
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Affiliation(s)
- Anna Stanicka
- Department of Invertebrate Zoology and Parasitology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland.
| | - Anna Cichy
- Department of Invertebrate Zoology and Parasitology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland
| | - Jana Bulantová
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague, Czechia
| | - Anna Maria Labecka
- Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
| | - Adam Marcin Ćmiel
- Institute of Nature Conservation, Polish Academy of Sciences, al. A. Mickiewicza 33, 31-120 Kraków, Poland
| | - Julita Templin
- Department of Invertebrate Zoology and Parasitology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland
| | - Petr Horák
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague, Czechia
| | - Elżbieta Żbikowska
- Department of Invertebrate Zoology and Parasitology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland
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Xie L, Gao X, Liu Y, Yang B, Wang B, Zhao J, Xing Q. Biogeochemical properties and fate of dissolved organic matter in wet deposition: Insights from a mariculture area in North Yellow Sea. Sci Total Environ 2022; 844:157130. [PMID: 35792266 DOI: 10.1016/j.scitotenv.2022.157130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 03/20/2022] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
To address the potential roles of atmospheric wet deposition in carbon cycling in coastal waters, a comprehensive study of the biogeochemical properties of dissolved organic matter (DOM) in precipitation and the resulting implication in a mariculture area in North Yellow Sea was conducted. The annual mean concentrations of dissolved organic carbon (DOC), chromophoric and fluorescent dissolved organic matter (CDOM and FDOM) were 1.52 ± 1.52 mg C L-1, 0.36 ± 0.66 m-1 and 0.38 ± 0.35 QSU, respectively. The concentrations of most DOM proxies exhibited significant negative correlations with the corresponding precipitation amount (R2 = 0.15-0.40, P < 0.01), but the dilution effects became less significant when the precipitation amount exceeded 10.2, 10.7, 10.2 and 2.4 mm for DOC, CDOM, highly‑oxygenated and hypoxic structured humic-like substances, respectively. Seasonally, the dominant precipitation type in winter was snowfall, in which the DOM contained more high-molecular-weight compounds with higher aromaticity and humification degree, while the characteristics of DOM in intensive rainfall in summer were contrary to those in winter. The wet deposition flux of DOC to this region was estimated to be 6.31 × 108 g C a-1, which was 3.3 and 1.4 times that of the dry deposition and local riverine input, thereby contributing to 4.0 % of the DOC storage in the study area. In summer, the intensive input of DOC through wet deposition (0.43 g C m-2) to surface seawater could enrich its bioavailable DOC by 10.7 μmol L-1, the complete aerobic decomposition of which would cause an obvious dissolved oxygen depletion in the surface seawater by 21.4 μmol L-1, demonstrating the influence of wet deposition on summer deoxygenation in coastal waters.
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Affiliation(s)
- Lei Xie
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuelu Gao
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong 266071, China.
| | - Yongliang Liu
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong 266071, China
| | - Bo Yang
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, Guangdong 518114, China
| | - Bin Wang
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianmin Zhao
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong 266071, China
| | - Qianguo Xing
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong 266071, China
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Xie L, Gao X, Liu Y, Yang B, Wang B, Zhao J, Xing Q. Atmospheric wet deposition serves as an important nutrient supply for coastal ecosystems and fishery resources: Insights from a mariculture area in North China. Mar Pollut Bull 2022; 182:114036. [PMID: 35985129 DOI: 10.1016/j.marpolbul.2022.114036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 06/10/2022] [Revised: 07/31/2022] [Accepted: 08/07/2022] [Indexed: 06/15/2023]
Abstract
To determine the ecological effects of atmospheric wet deposition of dissolved nutrients on the coastal waters around the Yangma Island, rain and snow samples were collected and analyzed at a shore-based site for one year. The wet deposition fluxes of dissolved inorganic nitrogen and phosphorus (DIN and DIP) and dissolved organic nitrogen and phosphorus were 69.2, 0.136, 13.3 and 0.143 mmol m-2 a-1, respectively. In summer, the new production fueled by wet deposition accounted for 19.3 % of that in seawater and 16.4 % of the amount of particulate organic carbon ingested by the scallops cultivated in the study area, indicating the potential contribution of wet deposition to fishery resources. Meanwhile, precipitation increased the seasonal average DIN/DIP ratios in surface seawater by 17.7 %, 16.3 %, 23.4 % and 6.5 % in spring, summer, autumn and winter, respectively, which could change the composition of ecological community and cause obvious negative impact on the ecosystem and mariculture.
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Affiliation(s)
- Lei Xie
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuelu Gao
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong 266071, China.
| | - Yongliang Liu
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China
| | - Bo Yang
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, Guangdong 518114, China
| | - Bin Wang
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianmin Zhao
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong 266071, China
| | - Qianguo Xing
- CAS Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China; Shandong Key Laboratory of Coastal Environmental Processes, Yantai, Shandong 264003, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong 266071, China
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11
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Kittipongvises S, Phetrak A, Hongprasith N, Lohwacharin J. Unravelling capability of municipal wastewater treatment plant in Thailand for microplastics: Effects of seasonality on detection, fate and transport. J Environ Manage 2022; 302:113990. [PMID: 34717107 DOI: 10.1016/j.jenvman.2021.113990] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/10/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Many factors can affect microplastics (MPs) behaviors in aquatic environments. The effects of seasonal and meteorological conditions on MPs are not well understood. This study demonstrates the impacts of seasonality on the fate and transport, and the efficacy of MPs removal by a wastewater treatment plant. The fate and transport of MPs at a WWTP in Nonthaburi, Thailand were tracked during the dry and wet seasons of 2019-2020. Polypropylene (PP), polyethylene (PE), and toothpaste formulations were the most abundant MP types observed. Total detected MP quantities ranged between 76 and 192 particles L-1 during the dry season, and only 36-68 particles L-1 during the wet season, indicating runoff dilution effects. T-test analysis found a statistically significant difference between MP concentrations between the dry and wet seasons of 2019-2020. Spearman's correlation showed statistically strong negative relationships between MP concentrations versus wastewater flow, and MP concentrations versus precipitation; a positive correlation between MP abundance versus temperature in the treatment system was observed. During the dry seasons, MPs were mostly found in the aeration process, and were mostly rayon or polyester particles in the shape of fibers. Contrarily, in the wet seasons, MPs were detected in both the raw influent and aeration process, with PE, polyacrylate, and polyethylene terephthalate fragments dominating the make-up. MPs were also detected in the return activated sludge, thus calling for proper sludge age and drainage management. No MPs were detected in the plant's effluent during the wet season, suggesting that the plant had sufficient MPs removal capability during normal wet-season conditions. Overall, this study suggests that municipalities should focus on increasing MPs removal efficiency of wastewater treatment plants for dry seasons, while properly managing the water flows of combined sewage systems to prevent overflows that may inevitably become point-sources of MPs release into water bodies during wet seasons.
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Affiliation(s)
| | - Athit Phetrak
- Department of Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Narapong Hongprasith
- Department of Environmental Engineering, Faculty of Engineering Chulalongkorn University, Thailand
| | - Jenyuk Lohwacharin
- Department of Environmental Engineering, Faculty of Engineering Chulalongkorn University, Thailand; Professor Aroon Sorathesn Center of Excellence in Environmental Engineering, Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand.
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Yang J, Li T, Feng T, Yu Q, Su W, Zhou R, Li X, Li H. Water volume influences antibiotic resistomes and microbiomes during fish corpse decomposition. Sci Total Environ 2021; 789:147977. [PMID: 34052485 DOI: 10.1016/j.scitotenv.2021.147977] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 03/25/2021] [Revised: 05/07/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
Corpse decomposition may cause serious pollution (e.g., releasing antibiotic resistance genes) to the water environment, thereby threatening public health. However, whether antibiotic resistance genes (ARGs) and microbiomes are affected by different water volumes during carcass decomposition remains unknown. Here, we investigated the effects of large/small water volumes on microbial communities and ARGs during fish cadaver decomposition by 16S rRNA high-throughput sequencing and high-throughput quantitative PCR. The results showed that the large water volume almost eliminated the effects of corpse decomposition on pH, total organic carbon (TOC), and total nitrogen (TN). When the water volume enlarged by 62.5 fold, the relative abundances of some ARGs resisting tetracycline and sulfonamide during carcass decomposition decreased by 217 fold on average, while there was also a mean 5267 fold increase of vancomycin resistance genes. Compared with the control group, the enriched types of ARGs varied between the large and small volume. Water volume, mobile genetic elements, and carcass decomposition were the most important factors affecting ARG profiles. Many opportunistic pathogens (like Bacteroides and Comamonas) were enriched in the corpse group. Bacteroides and Comamonas may be potential hosts of ARGs, indicating the potential for the spread of ARGs to humans by water pathogenic bacteria. This research highlights that the "dilution effect" can contribute to eliminating this adverse effect during corpse decomposition to a certain extent. It may provide references for environmental governance and public health.
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Affiliation(s)
- Jiawei Yang
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Tongtong Li
- Department of Applied Biology, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Tianshu Feng
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Qiaoling Yu
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Wanghong Su
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Rui Zhou
- School of Public Health, Lanzhou University, Lanzhou 730000, China
| | - Xiangzhen Li
- Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan, China.
| | - Huan Li
- School of Public Health, Lanzhou University, Lanzhou 730000, China; Center for Grassland Microbiome, Lanzhou University, Lanzhou 730000, China.
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Gandy S, Kilbride E, Biek R, Millins C, Gilbert L. Experimental evidence for opposing effects of high deer density on tick-borne pathogen prevalence and hazard. Parasit Vectors 2021; 14:509. [PMID: 34593023 PMCID: PMC8485466 DOI: 10.1186/s13071-021-05000-0] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/08/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Identifying the mechanisms driving disease risk is challenging for multi-host pathogens, such as Borrelia burgdorferi sensu lato (s.l.), the tick-borne bacteria causing Lyme disease. Deer are tick reproduction hosts but do not transmit B. burgdorferi s.l., whereas rodents and birds are competent transmission hosts. Here, we use a long-term deer exclosure experiment to test three mechanisms for how high deer density might shape B. burgdorferi s.l. prevalence in ticks: increased prevalence due to higher larval tick densities facilitating high transmission on rodents (M1); alternatively, reduced B. burgdorferi s.l. prevalence because more larval ticks feed on deer rather than transmission-competent rodents (dilution effect) (M2), potentially due to ecological cascades, whereby higher deer grazing pressure shortens vegetation which decreases rodent abundance thus reducing transmission (M3). METHODS In a large enclosure where red deer stags were kept at high density (35.5 deer km-2), we used an experimental design consisting of eight plots of 0.23 ha, four of which were fenced to simulate the absence of deer and four that were accessible to deer. In each plot we measured the density of questing nymphs and nymphal infection prevalence in spring, summer and autumn, and quantified vegetation height and density, and small mammal abundance. RESULTS Prevalence tended to be lower, though not conclusively so, in high deer density plots compared to exclosures (predicted prevalence of 1.0% vs 2.2%), suggesting that the dilution and cascade mechanisms might outweigh the increased opportunities for transmission mechanism. Presence of deer at high density led to shorter vegetation and fewer rodents, consistent with an ecological cascade. However, Lyme disease hazard (density of infected I. ricinus nymphs) was five times higher in high deer density plots due to tick density being 18 times higher. CONCLUSIONS High densities of tick reproduction hosts such as deer can drive up vector-borne disease hazard, despite the potential to simultaneously reduce pathogen prevalence. This has implications for environmental pathogen management and for deer management, although the impact of intermediate deer densities now needs testing.
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Affiliation(s)
- Sara Gandy
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK. .,The James Hutton Institute, Craigiebuckler, Aberdeen, UK.
| | - Elizabeth Kilbride
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Roman Biek
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Caroline Millins
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.,Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Lucy Gilbert
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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14
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Doussang D, Sallaberry-Pincheira N, Cabanne GS, Lijtmaer DA, González-Acuña D, Vianna JA. Specialist versus generalist parasites: the interactions between host diversity, environment and geographic barriers in avian malaria. Int J Parasitol 2021; 51:899-911. [PMID: 34044005 DOI: 10.1016/j.ijpara.2021.04.003] [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] [Received: 03/17/2020] [Revised: 04/03/2021] [Accepted: 04/12/2021] [Indexed: 10/21/2022]
Abstract
The specialist versus generalist strategies of hemoparasites in relation to their avian host, as well as environmental factors, can influence their prevalence, diversity and distribution. In this paper we investigated the influence of avian host species, as well as the environmental and geographical factors, on the strategies of Haemoproteus and Plasmodium hemoparasites. We determined prevalence and diversity by targeting their cytochrome b (Cytb) in a total of 2,590 passerine samples from 138 localities of Central and South America, and analysed biogeographic patterns and host-parasite relationships. We found a total prevalence of 23.2%. Haemoproteus presented a higher prevalence (15.3%) than Plasmodium (4.3%), as well as a higher diversity and host specificity. We determined that Plasmodium and Haemoproteus prevalences correlated positively with host diversity (Shannon index) and were significantly influenced by bird diversity, demonstrating a possible "amplification effect". We found an effect of locality and the avian family for prevalences of Haemoproteus and Plasmodium. These results suggest that Haemoproteus is more specialist than Plasmodium and could be mostly influenced by its avian host and the Andes Mountains.
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Affiliation(s)
- Daniela Doussang
- Facultad de Ciencias Veterinarias, Universidad de Concepción, Casilla 537, Chillán, Chile; Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Chile
| | | | - Gustavo S Cabanne
- Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina
| | - Darío A Lijtmaer
- Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina
| | - Daniel González-Acuña
- Facultad de Ciencias Veterinarias, Universidad de Concepción, Casilla 537, Chillán, Chile
| | - Juliana A Vianna
- Departamento de Ecosistemas y Medio Ambiente, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Código Postal, 6904411, Casilla 306, Correo 22, Santiago, Chile.
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15
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Cortez MH. Using sensitivity analysis to identify factors promoting higher versus lower infection prevalence in multi-host communities. J Theor Biol 2021; 526:110766. [PMID: 34019849 DOI: 10.1016/j.jtbi.2021.110766] [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: 12/22/2020] [Revised: 05/04/2021] [Accepted: 05/12/2021] [Indexed: 10/21/2022]
Abstract
Relationships between host species richness and levels of disease in a focal host are likely to be context-dependent, depending on the characteristics of which particular host species are present in a community. I use a multi-host epidemiological model with environmental transmission to explore how the characteristics of the host species (e.g., competence and competitive ability), host density, and the pathogen transmission mechanism affect the proportion of infected individuals (i.e., infection prevalence) in a focal host. My sensitivity-based approach identifies the indirect pathways through which specific ecological and epidemiological processes affect focal host infection prevalence. This in turn yields predictions about the context-dependent rules governing whether increased host species richness increases (amplifies) or decreases (dilutes) infection prevalence in a focal host. For example, in many cases, amplification and dilution are predicted to occur when added host species are sources or sinks of infectious propagules, respectively. However, if the added host species have strong and asymmetric competitive effects on resident host species, then amplification and dilution are predicted to occur when the added host species have stronger competitive effects on resident host species that are sources or sinks of infectious propagules, respectively. My results also predict that greater dilution and less amplification is more likely to occur under frequency-dependent direct transmission than density-dependent direct transmission when (i) the added hosts have lower competence than resident host species and (ii) interspecific competition between the added host species and resident host species is lower; the opposite conditions promote greater amplification and less dilution under frequency-dependent direct transmission. This work helps identify and explain the mechanisms shaping the context-dependent relationships between host species richness and disease in multi-host communities.
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Affiliation(s)
- Michael H Cortez
- Depart of Biological Science, Florida State University, Tallahassee, FL 32306, United States.
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16
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Ratti V, Winter JM, Wallace DI. Dilution and amplification effects in Lyme disease: Modeling the effects of reservoir-incompetent hosts on Borrelia burgdorferi sensu stricto transmission. Ticks Tick Borne Dis 2021; 12:101724. [PMID: 33878571 DOI: 10.1016/j.ttbdis.2021.101724] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 11/19/2022]
Abstract
The literature on Lyme disease includes a lively debate about the paradoxical role of changing deer populations. A decrease in the number of deer will both (1) reduce the incidence of Lyme disease by decreasing the host populations for ticks and therefore tick populations, and (2) enhance the incidence of Lyme disease by offering fewer reservoir-incompetent hosts for ticks, forcing the vector to choose reservoir-competent, and therefore possibly diseased, hosts to feed on. A review of field studies exploring the net impact of changing deer populations shows mixed results. In this manuscript, we investigate the hypothesis that the balance of these two responses to changing deer populations depends on the relative population sizes of reservoir-competent vs. reservoir-incompetent hosts and the presence of host preference in larval and adult stages. A temperature driven seasonal model of Borrelia burgdorferi sensu stricto (cause of Lyme disease) transmission among three host types (reservoir-competent infected and uninfected hosts, and reservoir-incompetent hosts) is constructed as a system of nonlinear ordinary differential equations. The model, which produces biologically reasonable results for both the tick vector Ixodes scapularis Say 1921 and the hosts, is used to investigate the effects of reservoir-incompetent host removal on both tick populations and disease prevalence for various relative population sizes of reservoir-competent hosts vs. reservoir-incompetent hosts. In summary, the simulation results show that the model with host preference appears to be more accurate than the one with no host preference. Given these results, we found that removal of adult I. scapularis(Say) hosts is likely to reduce questing nymph populations. At very low levels questing adult abundance may rise with lack of adult hosts. There is a dilution effect at low reservoir-competent host populations and there is an amplification effect at high reservoir-competent host populations.
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Affiliation(s)
- Vardayani Ratti
- Department of Mathematics and Statistics, California State University Chico, CA, United States.
| | - Jonathan M Winter
- Department of Geography, Dartmouth College, Hanover, NH, United States
| | - Dorothy I Wallace
- Department of Mathematics, Dartmouth College, Hanover, NH, United States
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17
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Connolly NM, Pearson RG. Do constrained immigration rates and high β diversity explain contrasting productivity-diversity patterns measured at different scales? Oecologia 2020; 194:481-90. [PMID: 32989572 DOI: 10.1007/s00442-020-04766-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 09/21/2020] [Indexed: 10/23/2022]
Abstract
The relationship between productivity and diversity is controversial because of disparity between unimodal and monotonic patterns, especially when occurring simultaneously at different scales. We used stream-side artificial channels to investigate how the availability of a major resource (leaf litter) affected stream invertebrate abundance and diversity at leaf-pack and whole-channel scales. At the larger scale, invertebrate diversity increased monotonically with increasing litter resource density, whereas at the smaller scale the relationship was hump-shaped, in keeping with reports in the literature. This divergence at higher resource levels suggests that multiple mechanisms may be operating. Our results indicate that consistently high species turnover (β diversity) caused the monotonic pattern because of a species-area or "sampling effect" in which new species accumulate with increasing number of samples. The hump-shaped pattern was due to constrained immigration because of a "dilution effect" in which a limited number of immigrants is spread out among the increasing number of available patches. We propose that the relationship between productivity or resource availability and α diversity is generally hump-shaped and the scale-dependent contrast in the relationship only arises where the species pool is large and β diversity is high. Differences in β diversity may, therefore, explain some of the contrasting patterns in the productivity-diversity relationship previously reported.We suggest that continuing immigration by rare taxa is important in sustaining species diversity when productivity is high. The hump-shaped pattern has implications for the impact of anthropogenic ecosystem enrichment on species diversity.
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18
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Yang R, Sun H, Chen B, Yang M, Zeng Q, Zeng C, Huang J, Luo H, Lin D. Temporal variations in riverine hydrochemistry and estimation of the carbon sink produced by coupled carbonate weathering with aquatic photosynthesis on land: an example from the Xijiang River, a large subtropical karst-dominated river in China. Environ Sci Pollut Res Int 2020; 27:13142-13154. [PMID: 32016871 DOI: 10.1007/s11356-020-07872-8] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
The coupled carbonate weathering represents a significant carbon sink and can be controlled by the riverine hydrochemical variations. However, magnitudes, variations, and mechanisms responsible for the carbon sink produced by coupled carbonate weathering are unclear. In view of this, temperature, pH, dissolved oxygen, turbidity, electrical conductivity, and discharge of the Xijiang River at Wuzhou Hydrologic Gauging Station was recorded during October 2013 to September 2015 to elucidate the temporal variations in riverine hydrochemistry and their controlling mechanisms. To obtain the complete carbon sink flux (CSF) produced by coupled carbonate weathering with terrestrial aquatic photosynthesis in the river basin, the fluxes of dissolved inorganic carbon (DIC), autochthonous organic carbon (AOC, sourced from the transformation of DIC via aquatic photosynthesis), and sedimentary AOC were all considered. The results show that seasonal hydrochemical variations in the Xijiang River were related not only to dilution effects but also aquatic primary production. These results demonstrate that the variations in discharge caused by rainfall played a dominant role in controlling the variations in the CSF due to the chemostatic behavior of DIC and dissolved organic carbon (DOC). The CSF of the Xijiang River produced by coupled carbonate weathering was calculated as 11.06 t C km-2 a-1, including DIC carbon sink flux of 6.56 t C km-2 a-1, AOC flux (FAOC) of 2.25 t C km-2 a-1, and sedimentary AOC flux (FSAOC) of 2.25 t C km-2 a-1. The FAOC and FSAOC together accounted for approximately 69% of DIC carbon sink flux, or approximately 41% of the CSF, indicating that the riverine AOC flux may be high and must be considered in the estimation of rock weathering-related carbon sinks.
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Affiliation(s)
- Rui Yang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- College of Public Management, Guizhou University of Finance and Economics, Guiyang, 550025, China
| | - Hailong Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China.
| | - Bo Chen
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- College of Public Management, Guizhou University of Finance and Economics, Guiyang, 550025, China
| | - Mingxing Yang
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
- School of Resource and Environment Engineering, Guizhou Institute of Technology, Guiyang, 550003, China
| | - Qingrui Zeng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Cheng Zeng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Jie Huang
- Wuzhou Hydrology and Water Resources Bureau, Wuzhou, 543000, China
| | - Huixian Luo
- Wuzhou Hydrology and Water Resources Bureau, Wuzhou, 543000, China
| | - Danhui Lin
- Wuzhou Hydrology and Water Resources Bureau, Wuzhou, 543000, China
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Su M, Yang Y, Hui C. How intraguild predation affects the host diversity-disease relationship in a multihost community. J Theor Biol 2020; 490:110174. [PMID: 31987878 DOI: 10.1016/j.jtbi.2020.110174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 12/19/2019] [Accepted: 01/23/2020] [Indexed: 11/23/2022]
Abstract
Broad evidence has shown that host diversity can impede disease invasion and reduce the eventual prevalence, but little is known on how species interactions play in shaping this host diversity-disease relationship. Previous work has illustrated that intraguild predation (IGP), combined with parasite-mediated indirect effects, can have strong influences on parasitic infection. Following this line of thinking, we here examine the role of predatory interactions in the disease transmission within a multihost community. Through varying fractions of IGP in a competitive community, we show that, dependent on the fraction of predatory interactions, species richness can switch from enhancing to inhibiting disease establishment/prevalence. Without IGP interactions, high host species richness can likely weaken the 'dilution effect' and in some cases even enhance the disease establishment (and/or prevalence) due to the existence of alternative sources for infection, whereas IGP can generally heighten the negative diversity-disease relationship due to the reduction of encounter rate between prospective hosts and parasites. Although trait-mediated interactions (captured as the infection-induced changes in predation rate) only weakly affect disease prevalence, density-mediated interactions (captured as the additional infection-induced mortality) can pose a relatively strong influence on disease transmission. Our results thus underline the importance of considering species interactions when investigating the host diversity-disease relationship.
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Stuart P, Paredis L, Henttonen H, Lawton C, Ochoa Torres CA, Holland CV. The hidden faces of a biological invasion: parasite dynamics of invaders and natives. Int J Parasitol 2020; 50:111-23. [PMID: 31981672 DOI: 10.1016/j.ijpara.2019.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/02/2019] [Accepted: 11/08/2019] [Indexed: 02/07/2023]
Abstract
One of the primary drivers of emerging infectious diseases (EIDs) is human intervention via host or parasite translocations. A unique opportunity to study host and parasite dispersal during a bio-invasion currently exists in Ireland due to the introduction of the bank vole (Myodes glareolus) in the 1920s. The continuing range expansion of M. glareolus within Ireland presents a natural large-scale perturbation experiment. This study used the Irish M. glareolus model to conduct a spatiotemporal study analysing the parasite dynamics of native and invasive species throughout their range. Myodes glareolus and native Apodemus sylvaticus were trapped in woodlands across Ireland and surveyed for their helminth parasites. Myodes glareolus in Ireland were found to have lower parasite diversity in comparison to records of M. glareolus from across Europe and A. sylvaticus in Ireland. Increased density of M. glareolus resulted in a dilution effect, with significantly lower levels of parasitism overall in native hosts, where M. glareolus has been established longest. However, three helminth parasite species of A. sylvaticus increased in abundance in the presence of M. glareolus. Furthermore, M. glareolus at the expansion front were less parasitised (lower abundance and prevalence of certain parasites and lower parasite diversity) than M. glareolus from the core population. This "enemy release" is believed to be mediating the continued successful spread of the invader across Ireland. Our results identify two important variables, seasonality and the stage of the invasion, which should not be overlooked when investigating or managing the changing distribution of hosts and their parasites. Studies of bio-invasions and parasite transmission have primarily focused on the invasive host species or the native host species in cases where virulent pathogen spillover is observed. Our results demonstrate how the concurrent study of invasive and native hosts, and the careful identification of their parasite communities, allows the dynamic processes influencing the parasite component and intracommunity to be identified.
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21
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Sanborn AN, Noguchi T, Tripp J, Stewart N. A dilution effect without dilution: When missing evidence, not non-diagnostic evidence, is judged inaccurately. Cognition 2019; 196:104110. [PMID: 31816520 DOI: 10.1016/j.cognition.2019.104110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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: 10/04/2018] [Revised: 10/11/2019] [Accepted: 10/14/2019] [Indexed: 11/29/2022]
Abstract
When asked to combine two pieces of evidence, one diagnostic and one non-diagnostic, people show a dilution effect: the addition of non-diagnostic evidence dilutes the overall strength of the evidence. This non-normative effect has been found in a variety of tasks and has been taken as evidence that people inappropriately combine information. In a series of five experiments, we found the dilution effect, but surprisingly it was not due to the inaccurate combination of diagnostic and non-diagnostic information. Because we have objectively correct answers for our task, we could see that participants were relatively accurate in judging diagnostic evidence combined with non-diagnostic evidence, but overestimated the strength of diagnostic evidence alone. This meant that the dilution effect - the gap between diagnostic evidence alone and diagnostic evidence combined with non-diagnostic evidence - was not caused by dilution. We hypothesized that participants were filling in "missing" evidence in a biased fashion when presented with diagnostic evidence alone. This hypothesis best explained the experimental results.
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Abstract
Species diversity has been proposed to decrease prevalence of disease in a wide variety of host-pathogen systems, in a phenomenon labeled the dilution effect. This phenomenon was first proposed and tested for vector-borne diseases but was later extended to directly transmitted parasite systems such as hantavirus. Though there seems to be clear evidence for the dilution effect in some hantavirus/rodent systems, the generality of this hypothesis remains debated. In the present meta-analysis, we examined the evidence supporting the dilution effect for hantavirus/rodent systems in the Americas. General linear models employed on data from 56 field studies identified the abundance of the reservoir rodent species and its relative proportion in the community as the only relevant variables explaining the prevalence of antibodies against hantavirus in the reservoir. Thus, we found no clear support for the dilution effect hypothesis for hantavirus/rodent systems in the Americas.
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Affiliation(s)
- María Victoria Vadell
- Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, Campus Miguelete, 25 de Mayo y Francia, 1650, San Martín, Buenos Aires, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
- Instituto Nacional de Medicina Tropical (INMeT)-ANLIS "Dr. Carlos G. Malbrán", Puerto Iguazú, Misiones, Argentina.
| | - Isabel Elisa Gómez Villafañe
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Departamento de Ecología, Genética y Evolución, IEGEBA (CONICET-UBA), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Aníbal Eduardo Carbajo
- Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, Campus Miguelete, 25 de Mayo y Francia, 1650, San Martín, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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Roiz D, Vázquez A, Ruiz S, Tenorio A, Soriguer R, Figuerola J. Evidence that Passerine Birds Act as Amplifying Hosts for Usutu Virus Circulation. Ecohealth 2019; 16:734-742. [PMID: 31628631 DOI: 10.1007/s10393-019-01441-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [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: 08/11/2017] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
Environment determines the distribution and prevalence of vector-borne pathogens due to its direct and indirect effects on the hosts, vectors, and pathogens. To investigate the relationship between Usutu virus occurrence and host biodiversity and to characterize the nidus of infection, we used field-based measures of host diversity and density (all birds and only passerines), vector abundance, landscape and Usutu virus prevalence (mosquito infection rate), an emergent disease with a similar cycle to West Nile virus. We collected 908,237 female mosquitoes in an area of 54,984 ha in the Doñana National Park, southern Spain. We identified the mosquitoes and screened them for viruses, censused birds, characterized landscape and climatic variables, and then modeled the presence and infection rate of the virus in relation to host, vector, climatic, and landscape variables. Monthly Usutu presence, detected in Culex perexiguus, was positively related to Passeriformes richness and secondarily to NDVI in the previous month. Our results suggest that Usutu prevalence may be higher when and where host (passerine) richness was high, and thus challenging the conventional idea that host biodiversity reduces flavivirus amplification.
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Affiliation(s)
- David Roiz
- UMR, IRD224-CNRS5290-UM, Infectious Diseases and Vectors: Ecology, Genetics, Evolution and Control (MIVEGEC), Institut de Recherche pour le Développement (IRD), 911, Avenue Agropolis, 34394, Montpellier, France.
- Estación Biológica de Doñana (CSIC), Av. Américo Vespucio, 26, 41092, Seville, Spain.
| | - Ana Vázquez
- Laboratorio de Arbovirus y Enfermedades Viricas Importadas, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- CIBER Epidemiología y Salud Publica (CIBERESP), Madrid, Spain
| | - Santiago Ruiz
- Diputación de Huelva, Área de Medio Ambiente, Servicio de Control de Mosquitos, Huelva, Spain
- CIBER Epidemiología y Salud Publica (CIBERESP), Madrid, Spain
| | - Antonio Tenorio
- Laboratorio de Arbovirus y Enfermedades Viricas Importadas, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Ramón Soriguer
- Estación Biológica de Doñana (CSIC), Av. Américo Vespucio, 26, 41092, Seville, Spain
- CIBER Epidemiología y Salud Publica (CIBERESP), Madrid, Spain
| | - Jordi Figuerola
- Estación Biológica de Doñana (CSIC), Av. Américo Vespucio, 26, 41092, Seville, Spain
- CIBER Epidemiología y Salud Publica (CIBERESP), Madrid, Spain
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24
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Abstract
The biomedical literature describes clearly the direct mechanisms influencing weight gain, but broader public discourse on the subject is rife with misleading claims about the factors that cause people to gain or lose weight. We examine how such misleading claims can dilute accurate information to the point that people arrive at poor judgments about the direct causes of weight gain. We adapt the conventional experimental paradigm used in dilution research (Nisbett, Zukier, & Lemley, 1981) to measure the effect of different information levels of dilution. We use a pair of online survey experiments to distinguish the effects of receiving distractingly plausible information versus raw information overload. These experiments also probe the limits of the dilution effect by using a large national sample of participants who vary by their health information efficacy and other potential moderators. Results suggest that public confusion about weight loss may stem from a dilution effect, which remains constant across a wide range of subgroups one might otherwise expect to resist it.
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Affiliation(s)
- John Gastil
- Department of Communication Arts & Sciences, Pennsylvania State University
| | - Robert Marriott
- Department of Communication Arts & Sciences, Pennsylvania State University
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25
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Kain MP, Bolker BM. Predicting West Nile virus transmission in North American bird communities using phylogenetic mixed effects models and eBird citizen science data. Parasit Vectors 2019; 12:395. [PMID: 31395085 PMCID: PMC6686473 DOI: 10.1186/s13071-019-3656-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [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: 11/28/2018] [Accepted: 08/03/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND West Nile virus (WNV) is a mosquito-transmitted disease of birds that has caused bird population declines and can spill over into human populations. Previous research has identified bird species that infect a large fraction of the total pool of infected mosquitoes and correlate with human infection risk; however, these analyses cover small spatial regions and cannot be used to predict transmission in bird communities in which these species are rare or absent. Here we present a mechanistic model for WNV transmission that predicts WNV spread (R0) in any bird community in North America by scaling up from the physiological responses of individual birds to transmission at the level of the community. We predict unmeasured bird species' responses to infection using phylogenetic imputation, based on these species' phylogenetic relationships with bird species with measured responses. RESULTS We focused our analysis on Texas, USA, because it is among the states with the highest total incidence of WNV in humans and is well sampled by birders in the eBird database. Spatio-temporal patterns: WNV transmission is primarily driven by temperature variation across time and space, and secondarily by bird community composition. In Texas, we predicted WNV R0 to be highest in the spring and fall when temperatures maximize the product of mosquito transmission and survival probabilities. In the most favorable months for WNV transmission (April, May, September and October), we predicted R0 to be highest in the "Piney Woods" and "Oak Woods & Prairies" ecoregions of Texas, and lowest in the "High Plains" and "South Texas Brush County" ecoregions. Dilution effect: More abundant bird species are more competent hosts for WNV, and predicted WNV R0 decreases with increasing species richness. Keystone species: We predicted that northern cardinals (Cardinalis cardinalis) are the most important hosts for amplifying WNV and that mourning doves (Zenaida macroura) are the most important sinks of infection across Texas. CONCLUSIONS Despite some data limitations, we demonstrate the power of phylogenetic imputation in predicting disease transmission in heterogeneous host communities. Our mechanistic modeling framework shows promise both for assisting future analyses on transmission and spillover in heterogeneous multispecies pathogen systems and for improving model transparency by clarifying assumptions, choices and shortcomings in complex ecological analyses.
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Affiliation(s)
- Morgan P. Kain
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1 Canada
| | - Benjamin M. Bolker
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1 Canada
- Department of Mathematics and Statistics, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1 Canada
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26
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Sun Y, Hou M, Mur LAJ, Yang Y, Zhang T, Xu X, Huang S, Tong H. Nitrogen drives plant growth to the detriment of leaf sugar and steviol glycosides metabolisms in Stevia (Stevia rebaudiana Bertoni). Plant Physiol Biochem 2019; 141:240-249. [PMID: 31195254 DOI: 10.1016/j.plaphy.2019.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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: 04/17/2019] [Revised: 05/26/2019] [Accepted: 06/07/2019] [Indexed: 06/09/2023]
Abstract
Steviol glycosides (SGs) in Stevia (Stevia rebaudiana Bertoni) leaves are important due to their high sweetness and low calorific value. The yield of SGs is dependent on fertilization regimes, but the relationship between nitrogen (N) administration and SGs synthesis is still unclear. In this study, we investigate the effects of N rates on SGs production through hydroponic and plot experiments. The SGs yield was not significantly changed by N fertilization, but leaf SGs concentrations were significantly reduced due to the "dilution effect". Additionally, N addition decreased leaf carbon (C)/N ratio and soluble sugar concentration, accompanied with the inhibited phosphoenolpyruvate carboxylase and L-phenylalanine ammonia_lyase activities. A significant positive correlation between leaf SGs concentrations, C/N ratio and soluble sugar concentration was observed. Overall, we suggest that N-driven Stevia growth negatively affects SGs concentrations. The leaf C/N ratio and soluble sugar changes indicated the occurrence of metabolic reprogramming.
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Affiliation(s)
- Yuming Sun
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China.
| | - Menglan Hou
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Luis A J Mur
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3DA, UK
| | - Yongheng Yang
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Ting Zhang
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Xiaoyang Xu
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Suzhen Huang
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China
| | - Haiying Tong
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China.
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27
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Lievens EJP, Rode NO, Landes J, Segard A, Jabbour-Zahab R, Michalakis Y, Lenormand T. Long-term prevalence data reveals spillover dynamics in a multi-host (Artemia), multi-parasite (Microsporidia) community. Int J Parasitol 2019; 49:471-480. [PMID: 30904622 DOI: 10.1016/j.ijpara.2019.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/24/2019] [Accepted: 01/27/2019] [Indexed: 01/09/2023]
Abstract
In the study of multi-host parasites, it is often found that host species contribute asymmetrically to parasite transmission. Yet in natural populations, identifying which hosts contribute to parasite transmission and maintenance is a recurring challenge. Here, we approach this issue by taking advantage of natural variation in the composition of a host community. We studied the brine shrimps Artemia franciscana and Artemia parthenogenetica and their microsporidian parasites Anostracospora rigaudi and Enterocytospora artemiae. Previous laboratory experiments had shown that each host can transmit both parasites, but could not predict their actual contributions to the parasites' maintenance in the field. To resolve this, we gathered long-term prevalence data from a metacommunity of these species. Metacommunity patches could contain either or both of the Artemia host species, so that the presence of the hosts could be linked directly to the persistence of the parasites. First, we show that the microsporidian A. rigaudi is a spillover parasite: it was unable to persist in the absence of its maintenance host A. parthenogenetica. This result was particularly striking, as A. rigaudi displayed both high prevalence (in the field) and high infectivity (when tested in the laboratory) in both hosts. Moreover, the seasonal presence of A. parthenogenetica imposed seasonality on the rate of spillover, causing cyclical pseudo-endemics in the spillover host A. franciscana. Second, while our prevalence data was sufficient to identify E. artemiae as either a spillover or a facultative multi-host parasite, we could not distinguish between the two possibilities. This study supports the importance of studying the community context of multi-host parasites, and demonstrates that in appropriate multi-host systems, sampling across a range of conditions and host communities can lead to clear conclusions about the drivers of parasite persistence.
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Affiliation(s)
- Eva J P Lievens
- UMR 5175 CEFE, CNRS-Université de Montpellier-Université P. Valéry-EPHE, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France; UMR 5290 MIVEGEC, CNRS-IRD-Université de Montpellier, 911 Avenue Agropolis BP 64501, 34394 Montpellier, Cedex 5, France.
| | - Nicolas O Rode
- UMR 5175 CEFE, CNRS-Université de Montpellier-Université P. Valéry-EPHE, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France
| | - Julie Landes
- UMR 5175 CEFE, CNRS-Université de Montpellier-Université P. Valéry-EPHE, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France
| | - Adeline Segard
- UMR 5175 CEFE, CNRS-Université de Montpellier-Université P. Valéry-EPHE, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France
| | - Roula Jabbour-Zahab
- UMR 5175 CEFE, CNRS-Université de Montpellier-Université P. Valéry-EPHE, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France
| | - Yannis Michalakis
- UMR 5290 MIVEGEC, CNRS-IRD-Université de Montpellier, 911 Avenue Agropolis BP 64501, 34394 Montpellier, Cedex 5, France
| | - Thomas Lenormand
- UMR 5175 CEFE, CNRS-Université de Montpellier-Université P. Valéry-EPHE, 1919 Route de Mende, 34293 Montpellier, Cedex 5, France
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28
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Huang CI, Kay SC, Davis S, Tufts DM, Gaffett K, Tefft B, Diuk-Wasser MA. High burdens of Ixodes scapularis larval ticks on white-tailed deer may limit Lyme disease risk in a low biodiversity setting. Ticks Tick Borne Dis 2018; 10:258-268. [PMID: 30446377 PMCID: PMC6377166 DOI: 10.1016/j.ttbdis.2018.10.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [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: 07/05/2018] [Revised: 10/25/2018] [Accepted: 10/28/2018] [Indexed: 11/24/2022]
Abstract
An inverse relationship between biodiversity and human health has been termed the ‘dilution effect’ paradigm. In the case of tick-borne infections such as Lyme disease, the key assumption is that Borrelia burgdorferi sensu lato abundance is increased by the loss of less competent (dilution) hosts as biodiversity declines. White-tailed deer play a dual role in the pathogen cycle, as key reproductive hosts for adult ticks and incompetent hosts for the pathogen. While the role of deer as hosts of adult ticks is well established, the extent to which deer also feed immature ticks and reduce the proportion infected is unknown because of logistic constraints in measuring this empirically. We estimated the proportion of larvae that fed on deer in an extremely species-poor community on Block Island, RI, where tick nymphal infection prevalence was found to be lower than expected. In 2014, we measured the density, larval tick burdens, and realized reservoir competence of small mammal and bird hosts on Block Island, RI. In 2015, we measured the infection prevalence of host-seeking Ixodes scapularis nymphs resulting from larvae fed on available hosts in 2014. We back-estimated the proportion of larvae expected to have fed on deer in 2014 (the only unknown parameter) to result in the nymphal infection prevalence observed in 2015. Back-estimation predicted that 29% of larval ticks must have fed on deer to yield the observed 30% nymphal infection prevalence. In comparison, the proportion of larvae feeding on mice was 44% and 27% on birds. Our study identified an influential role of deer in reducing nymphal tick infection prevalence and a potential role as dilution hosts if the reduction in nymphal infection prevalence outweighs the role of deer as tick population amplifiers. Because both deer and competent hosts may increase in anthropogenic, fragmented habitats, the links between fragmentation, biodiversity, and Lyme disease risk may be complex and difficult to predict. Furthermore, a nonlinear relationship between deer abundance and Lyme disease risk would reduce the efficacy of deer population reduction efforts to control Lyme disease.
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Affiliation(s)
- Ching-I Huang
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Ave., 10027 New York, NY, United States.
| | - Samantha C Kay
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Ave., 10027 New York, NY, United States.
| | - Stephen Davis
- School of Science, Royal Melbourne Institute of Technology, 124 La Trobe St., Melbourne, Australia.
| | - Danielle M Tufts
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Ave., 10027 New York, NY, United States.
| | - Kimberley Gaffett
- The Nature Conservancy on Block Island, P.O. Box 1287, Block Island, RI 02807, United States.
| | - Brian Tefft
- Rhode Island Department of Environmental Management, Division of Fish and Wildlife, 277 Great Neck Road West Kingston, RI 02892, United States.
| | - Maria A Diuk-Wasser
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Ave., 10027 New York, NY, United States.
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29
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Vielma S, Lagrue C, Poulin R, Selbach C. Non-host organisms impact transmission at two different life stages in a marine parasite. Parasitol Res 2018; 118:111-117. [PMID: 30343421 DOI: 10.1007/s00436-018-6121-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/15/2018] [Indexed: 10/28/2022]
Abstract
The potential for local biodiversity to 'dilute' infection risk has been shown to be particularly important in aquatic trematodes, where non-host organisms can feed on free-living infective stages (cercariae) and reduce transmission rates to target hosts. Non-host organisms could also impact transmission during other stages of the trematode life cycle. In Philophthalmus spp., cercariae encyst as metacercariae on external surfaces, where they remain exposed to the adverse effects of non-host organisms. In laboratory experiments, we tested the potential for a range of non-host organisms to (i) prey on cercariae, (ii) induce early (i.e., faster) encystment and (iii) prey on or destroy metacercariae. Our results show that intertidal anemones, and to a lesser extent clams, can consume substantial numbers of cercariae. However, we found no strong evidence that the presence of these predators causes cercariae to encyst faster as a way to escape from predation. We also found that grazing snails can reduce numbers of encysted metacercariae, either by eating or crushing them. Our findings add to the growing evidence that trematode transmission success can be strongly affected by the local diversity of non-host organisms. They also reinforce the notion that parasites are potentially important food items for many organisms, thus playing roles other than consumers in many food webs.
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Affiliation(s)
- Sofia Vielma
- Institute of Biology, Faculty of Sciences, University of Pécs, Pécs, Hungary
| | - Clément Lagrue
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Robert Poulin
- Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand
| | - Christian Selbach
- Department of Zoology, University of Otago, PO Box 56, Dunedin, New Zealand.
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30
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Sun P, Wronski T, Bariyanga JD, Apio A. Gastro-intestinal parasite infections of Ankole cattle in an unhealthy landscape: An assessment of ecological predictors. Vet Parasitol 2018; 252:107-16. [PMID: 29559130 DOI: 10.1016/j.vetpar.2018.01.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 01/20/2018] [Accepted: 01/27/2018] [Indexed: 01/26/2023]
Abstract
The distribution of gastro-intestinal (GI) parasites across landscapes is closely related to the spatial distribution of hosts. In GI parasites with environmental life stages, the vitality of parasites is also affected by ecological and landscape-related components of the environment. This is particularly relevant for domestic livestock species that are often kept across habitats with varying degrees of degradation, exposing them to a wide range of environmentally robust parasite species. In our study, we examined the effect of environmental and anthropogenic factors on the prevalence and intensity of GI parasites across a free-ranging stock of Ankole cattle in the Mutara rangelands of northeastern Rwanda. Prevalence and intensity of each parasite type (i.e., strongyle-type nematodes, Strongyloides spp., Moniezia spp., and Eimeria spp.) were used as dependent variables. Two fixed factors related to season and conservation-political history, together with three principal components (condensed from nine ecological variables) were used as independent covariates in a univariate General Linear Model (GLM). Major effects on the prevalence and intensity of strongyle-type nematodes and on the intensity of Eimeria spp. were found in that vegetation-related effects such as above-ground grass biomass in conjunction with a high degree of soil compaction had a negative relationship with these parasite types. These unexpected findings suggest that strongyle-type and coccidian infections increase with increasing rangeland degradation. Strongyle-type nematode prevalence and intensity were also negatively related to goat/sheep density, indicating a 'dilution effect' of GI infections between domestic livestock species.
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31
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Zimmermann MR, Luth KE, Esch GW. Snail species diversity impacts the infection patterns of Echinostoma spp.: Examples from field collected data. Acta Parasitol 2017; 62:493-501. [PMID: 28682781 DOI: 10.1515/ap-2017-0059] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 05/22/2017] [Indexed: 11/15/2022]
Abstract
Rapid losses of biodiversity due to the changing landscape have spurred increased interest in the role of species diversity and disease risk. A leading hypothesis for the importance of biodiversity in disease reduction is the dilution effect, which suggests that increasing species diversity within a system decreases the risk of disease among the organisms inhabiting it. The role of species diversity in trematode infection was investigated using field studies from sites across the U.S. to examine the impact of snail diversity in the infection dynamics of both first and second intermediate larval stages of Echinostoma spp. parasites. The prevalence of Echinostoma spp. sporocysts/rediae infection was not affected by increases in snail diversity, but significant negative correlations in metacercariae prevalence and intensity with snail diversity were observed. Additionally, varying effectiveness of the diluting hosts was found, i.e., snail species that were incompatible first intermediate hosts for Echinostoma spp. were more successful at diluting the echinostome parasites in the focal species, while H. trivolvis, a snail species that can harbor the first intermediate larval stages, amplified infection. These findings have important implications not only on the role of species diversity in reducing disease risk, but the success of the parasites in completing their life cycles and maintaining their abundance within an aquatic system.
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32
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Mohammed AN, Juhany KA, Kumar S, Kishore VR, Mohammad A. Effects of CO 2/N 2 dilution on laminar burning velocity of stoichiometric DME-air mixture at elevated temperatures. J Hazard Mater 2017; 333:215-221. [PMID: 28359037 DOI: 10.1016/j.jhazmat.2017.03.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/16/2017] [Accepted: 03/20/2017] [Indexed: 06/07/2023]
Abstract
The laminar burning velocity of CO2/N2 diluted stoichiometric dimethyl ether (DME) air mixtures is determined experimentally at atmospheric pressure and elevated mixture temperatures using a mesoscale high aspect-ratio diverging channel with inlet dimensions of 25mm×2mm. In this method, planar flames at different initial temperatures (Tu) were stabilized inside the channel using an external electric heater. The magnitude of burning velocities was acquired by measuring the flame position and initial temperature. The mass conservation of the mixture entering the inlet and the stationary planar flame front is applied to obtain the laminar burning velocity. Laminar burning velocity at different initial mixture temperatures is plotted with temperature ratio (Tu/Tu,o), where a reference temperature (Tu,o) of 300K is used. Enhancement in the laminar burning velocity is observed with mixture temperature for DME-air mixtures with CO2 and N2 dilutions. A significant decrease in the burning velocity and slight increase in temperature exponent of the stoichiometric DME-air mixture was observed with dilution at same temperatures. The addition of CO2 has profound influence when compared to N2 addition on both burning velocity and temperature exponent.
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Affiliation(s)
- Abdul Naseer Mohammed
- Department of Aeronautical Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Khalid A Juhany
- Department of Aeronautical Engineering, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sudarshan Kumar
- Department of Aerospace Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - V Ratna Kishore
- Department of Mechanical Engineering, Amrita School of Engineering, Coimbatore, Amrita Vishwa Vidyapeetham, Amrita University, India
| | - Akram Mohammad
- Department of Aeronautical Engineering, King Abdulaziz University, Jeddah, Saudi Arabia.
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33
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Yokoi T, Idogawa N, Kandori I, Nikkeshi A, Watanabe M. The choosing of sleeping position in the overnight aggregation by the solitary bees Amegilla florea urens in Iriomote Island of Japan. Naturwissenschaften 2017; 104:23. [PMID: 28271178 DOI: 10.1007/s00114-017-1438-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 11/29/2016] [Revised: 01/27/2017] [Accepted: 01/28/2017] [Indexed: 11/29/2022]
Abstract
In addition to the process of joining the sleeping aggregation, the choice of sleeping position is an important night-time behaviour of small diurnal insects because of the increased risk for predator attacks as well as bad weather. The aggregation behaviour of the solitary bee Amegilla florea urens was investigated to elucidate the choice of sleeping position on substrates. Male and female constructed single-sex aggregations on hanging leaves during May and June, respectively. Most individuals tended to form aggregations with other individuals while few individuals slept alone. During the aggregation forming, both the number of individuals that tried to join the aggregation and the completion time of aggregation increased with the number of sleeping individuals, whereas the success rate of joining was unaffected. The sleeping positions of subsequent arrivals on the substrates were higher than those of the first arrivals in female aggregations. Therefore, the first female to arrive tended to be located near the bottom of a hanging substrate. Dissecting sleeping females showed that they contained mature oocytes, indicating that sexually mature individuals formed aggregations. In male aggregations, however, we could not find a clear relationship between the position on substrates and the arrival sequence. We suggest that the purpose for sleeping in aggregations might be a dilution effect for nocturnal predation and that the females that finished both nesting and foraging quickly could choose the optimal positions in the aggregation when they arrived on the sleeping substrates.
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Affiliation(s)
- Tomoyuki Yokoi
- Laboratory of Conservation Ecology, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba city, Ibaraki, 305-8572, Japan.
| | - Naoto Idogawa
- Laboratory of Conservation Ecology, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba city, Ibaraki, 305-8572, Japan
| | - Ikuo Kandori
- Laboratory of Entomology, Faculty of Agriculture, Kindai University, 3327-204 Nakamachi, Nara city, Nara, 631-8505, Japan
| | - Aoi Nikkeshi
- Laboratory of Conservation Ecology, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba city, Ibaraki, 305-8572, Japan
| | - Mamoru Watanabe
- Laboratory of Conservation Ecology, Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba city, Ibaraki, 305-8572, Japan
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Liu X, Shi J, Bo T, Meng Y, Zhan X, Zhang M, Zhang Y. Distributions and ecological risk assessment of estrogens and bisphenol A in an arid and semiarid area in northwest China. Environ Sci Pollut Res Int 2017; 24:7216-7225. [PMID: 28101707 DOI: 10.1007/s11356-017-8434-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [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: 09/20/2016] [Accepted: 01/09/2017] [Indexed: 06/06/2023]
Abstract
Free estrogens (estrone, E1; 17β-estradiol, 17β-E2; estriol, E3; and 17α-ethinylestradiol, EE2), their corresponding sulfate and glucuronide conjugates, and bisphenol A (BPA) were investigated in water and sediments in the Fen River catchment, an arid and semiarid area in northwest China. E1 and BPA were frequently detected in the wet and dry sampling seasons. In addition to the sulfate conjugates, other conjugated estrogens were not detected in water and sediments. The concentrations of these compounds in water generally increased from upstream to downstream. The concentrations in water samples of most sites were higher in the wet season than those in the dry season, but concentrations in sediments of most sites were higher in the dry season than those in the wet season. The distributions of these compounds in sediments were positively correlated with the total organic carbon (TOC) contents of sediments (0.3 < R 2 < 0.6, p < 0.01) and concentrations in water (0.25 < R 2 < 0.50, p < 0.01). In this catchment, E1 was the main contributor to endocrine disrupting risk. The surface water in most of the tributaries and the sewage in the drainage channels were at risk. The pore waters of sediments were at risk at most sampling sites.
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Affiliation(s)
- Xiaowei Liu
- Hefei University of Technology (Xuancheng Campus), Xuancheng, Anhui, 242000, China
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Jianghong Shi
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China.
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
| | - Ting Bo
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875, China
| | - Yaobin Meng
- Key Laboratory of Environmental Change and Natural Disaster (Ministry of Education), Beijing Normal University, Beijing, 100875, China
| | - Xinmin Zhan
- Civil Engineering, College of Engineering and Informatics, National University of Ireland, Galway, Ireland
| | - Mengtao Zhang
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Yang Zhang
- School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
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Levine RS, Hedeen DL, Hedeen MW, Hamer GL, Mead DG, Kitron UD. Avian species diversity and transmission of West Nile virus in Atlanta, Georgia. Parasit Vectors 2017; 10:62. [PMID: 28159002 PMCID: PMC5291963 DOI: 10.1186/s13071-017-1999-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [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: 07/01/2016] [Accepted: 01/24/2017] [Indexed: 11/10/2022] Open
Abstract
Background The dilution effect is the reduction in vector-borne pathogen transmission associated with the presence of diverse potential host species, some of which are incompetent. It is popularized as the notion that increased biodiversity leads to decreased rates of disease. West Nile virus (WNV) is an endemic mosquito-borne virus in the United States that is maintained in a zoonotic cycle involving various avian host species. In Atlanta, Georgia, substantial WNV presence in the vector and host species has not translated into a high number of human cases. Methods To determine whether a dilution effect was contributing to this reduced transmission, we characterized the host species community composition and performed WNV surveillance of hosts and vectors in urban Atlanta between 2010 and 2011. We tested the relationship between host diversity and both host seroprevalence and vector infection rates using a negative binomial generalized linear mixed model. Results Regardless of how we measured host diversity or whether we considered host seroprevalence and vector infection rates as predictor variables or outcome variables, we did not detect a dilution effect. Rather, we detected an amplification effect, in which increased host diversity resulted in increased seroprevalence or infection rates; this is the first empirical evidence for this effect in a mosquito-borne system. Conclusions We suggest that this effect may be driven by an over-abundance of moderately- to poorly-competent host species, such as northern cardinals and members of the Mimid family, which cause optimal hosts to become rarer and present primarily in species-rich areas. Our results support the notion that dilution or amplification effects depend more on the identities of the species comprising the host community than on the absolute diversity of hosts. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-1999-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rebecca S Levine
- Department of Environmental Sciences, Emory University, 400 Dowman Drive, Math and Science Center 5th Floor, Suite E510, Atlanta, GA, 30322, USA.
| | - David L Hedeen
- Georgia Department of Transportation, Office of Environmental Services, One Georgia Center, 600 West Peachtree Street NW, Atlanta, GA, 30308, USA
| | - Meghan W Hedeen
- Georgia Department of Transportation, Office of Environmental Services, One Georgia Center, 600 West Peachtree Street NW, Atlanta, GA, 30308, USA
| | - Gabriel L Hamer
- Department of Entomology, Texas A&M University College of Agriculture and Life Sciences, TAMU 2475, College Station, TX, 77843, USA
| | - Daniel G Mead
- University of Georgia College of Veterinary Medicine, Southeastern Cooperative Wildlife Disease Study, 589 D.W. Brooks Drive, Athens, GA, 30602, USA
| | - Uriel D Kitron
- Department of Environmental Sciences, Emory University, 400 Dowman Drive, Math and Science Center 5th Floor, Suite E510, Atlanta, GA, 30322, USA
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Salakhieva D, Shevchenko V, Németh C, Gyarmati B, Szilágyi A, Abdullin T. Structure-biocompatibility and transfection activity relationships of cationic polyaspartamides with (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups. Int J Pharm 2016; 517:234-246. [PMID: 27931785 DOI: 10.1016/j.ijpharm.2016.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 10/02/2016] [Accepted: 12/02/2016] [Indexed: 01/18/2023]
Abstract
A series of 14 cationic derivatives of poly(aspartic acid) i.e. cationic polyaspartamides with different (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups was synthesized by nucleophilic addition on polysuccinimide. The resulting polyaspartamides have moderate amphiphilic properties. Relationships between the structure and ratio of side groups and in vitro properties of polyaspartamides, including their cytotoxic and membrane-damaging activity towards human cell lines, primary skin fibroblasts and erythrocytes, were established and discussed. Cationic polyaspartamides vary in their DNA-binding, condensing and nuclease-protecting characteristics depending on the concentration ratio of (dialkylamino)alkyl and alkyl or hydroxyalkyl side groups. Effective cell transfection was achieved upon polyaspartamide-mediated plasmid DNA delivery in serum-free medium in the presence of chloroquine. Effect of serum proteins adsorption onto polyaspartamide based polyplexes, and the role of concentration of polyplexes in culture medium in their colloidal stability and transfection process were demonstrated. Synthesized polyaspartamides are biocompatible and long-acting gene carriers, which are applied to cells after dilution and without washing, thus providing transfection level comparable to that of commercial transfection reagent.
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Affiliation(s)
- Diana Salakhieva
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia
| | - Vesta Shevchenko
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia
| | - Csaba Németh
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Benjámin Gyarmati
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - András Szilágyi
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary.
| | - Timur Abdullin
- Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia.
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Budria A, Candolin U. Do algae blooms dilute the risk of trematode infections in threespine sticklebacks? Curr Zool 2015; 61:991-995. [PMID: 32256535 DOI: 10.1093/czoolo/61.6.991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 09/04/2014] [Accepted: 11/19/2014] [Indexed: 11/13/2022] Open
Abstract
Human-induced growth of macro-algae is often assumed to increase trematode infections in fishes by increasing the abundance and condition of the parasite's intermediate host - snails - as this can boost the release of trematode larvae, cercariae, from the intermediate hosts. However, macro-algae can also impose barriers to the transmission of cercariae and reduce infections. We investigated whether an increased growth of filamentous algae affects the transmission of Diplostomum pseudospathaceum cercariae to the threespine stickleback Gasterosteus aculeatus, a common fish in eutrophied shallow waters. We exposed sticklebacks to trematode cercariae in the absence and presence of artificial filamentous algae, and recorded effects on the proportion of sticklebacks infected and the number of encysted metacercariae per fish. No significant effect of artificial algae on cercariae transmission was detected. However, the body size and the sex of the sticklebacks were strongly correlated with the number of encysted metacercariae per infected fish, with females and larger individuals being more infected. We discuss different factors that could have caused the difference in parasite transmission, including sex-related differences in body size and behaviour of sticklebacks.
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Affiliation(s)
- Alexandre Budria
- Department of Biosciences, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland
| | - Ulrika Candolin
- Department of Biosciences, University of Helsinki, P.O. Box 65, FI-00014 Helsinki, Finland
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Moens MAJ, Pérez-Tris J. Discovering potential sources of emerging pathogens: South America is a reservoir of generalist avian blood parasites. Int J Parasitol 2015; 46:41-9. [PMID: 26348660 DOI: 10.1016/j.ijpara.2015.08.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [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: 04/21/2015] [Revised: 08/04/2015] [Accepted: 08/07/2015] [Indexed: 11/29/2022]
Abstract
Generalist pathogens are capable of infecting a wide range of host species, and may pose serious disease emergence threats if accidentally moved outside their native areas. To date little effort has been devoted to identifying geographic areas that may act as reservoirs of generalist pathogens. According to current theory, where host diversity is high, parasite specialisation in one host species may be penalised by reduced host availability, while generalist parasites may benefit from the exploitation of various host species. Therefore natural selection could favor generalist parasites where host diversity is high. Here we explored if, in a highly diverse bird community in Ecuador, a generalist strategy is promoted among local Haemoproteus and Plasmodium blood-borne parasites compared with similar parasite communities throughout the world. We reconstructed the phylogenetic relationships of every parasite lineage in order to understand the evolution of host specificity in this megadiverse area. We found high levels of host generalisation for both parasite genera, and the mean host range of the Haemoproteus community in Ecuador was significantly higher than other parasite communities in other areas outside the Neotropics. Generalist Haemoproteus parasites in this bird community had diverse phylogenetic ancestry, were closely related to specialist parasites and were apparently endemic to the Amazon, showing that different parasites have independently evolved into host generalists in this region. Finally we show that Haemoproteus communities in Ecuador and South America are more generalist than in temperate areas, making this continent a hotspot of generalist Haemoproteus parasites for wild birds.
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Affiliation(s)
- Michaël A J Moens
- Department of Zoology and Physical Anthropology, Faculty of Biology, Complutense University of Madrid, Calle José Antonio Novais 12, 28040 Madrid, Spain.
| | - Javier Pérez-Tris
- Department of Zoology and Physical Anthropology, Faculty of Biology, Complutense University of Madrid, Calle José Antonio Novais 12, 28040 Madrid, Spain
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Pal S, Lee TR, Phelps S, De Wekker SFJ. Impact of atmospheric boundary layer depth variability and wind reversal on the diurnal variability of aerosol concentration at a valley site. Sci Total Environ 2014; 496:424-434. [PMID: 25105753 DOI: 10.1016/j.scitotenv.2014.07.067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [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: 03/29/2014] [Revised: 06/23/2014] [Accepted: 07/20/2014] [Indexed: 06/03/2023]
Abstract
The development of the atmospheric boundary layer (ABL) plays a key role in affecting the variability of atmospheric constituents such as aerosols, greenhouse gases, water vapor, and ozone. In general, the concentration of any tracers within the ABL varies due to the changes in the mixing volume (i.e. ABL depth). In this study, we investigate the impact on the near-surface aerosol concentration in a valley site of 1) the boundary layer dilution due to vertical mixing and 2) changes in the wind patterns. We use a data set obtained during a 10-day field campaign in which a number of remote sensing and in-situ instruments were deployed, including a ground-based aerosol lidar system for monitoring of the ABL top height (zi), a particle counter to determine the number concentration of aerosol particles at eight different size ranges, and tower-based standard meteorological instruments. Results show a clearly visible decreasing trend of the mean daytime zi from 2900 m AGL (above ground level) to 2200 m AGL during a three-day period which resulted in increased near-surface pollutant concentrations. An inverse relationship exists between the zi and the fine fraction (0.3-0.7 μm) accumulation mode particles (AMP) on some days due to the dilution effect in a well-mixed ABL. These days are characterized by the absence of daytime upvalley winds and the presence of northwesterly synoptic-driven winds. In contrast, on the days with an onset of an upvalley wind circulation after the morning transition, the wind-driven local transport mechanism outweighs the ABL-dilution effect in determining the variability of AMP concentration. The interplay between the ABL depth evolution and the onset of the upvalley wind during the morning transition period significantly governs the air quality in a valley and could be an important component in the studies of mountain meteorology and air quality.
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Affiliation(s)
- S Pal
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA.
| | - T R Lee
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
| | - S Phelps
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
| | - S F J De Wekker
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
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Zargar UR, Chishti MZ, Ahmad F, Rather MI. Does alteration in biodiversity really affect disease outcome? - A debate is brewing. Saudi J Biol Sci 2014; 22:14-8. [PMID: 25561877 DOI: 10.1016/j.sjbs.2014.05.004] [Citation(s) in RCA: 10] [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] [Received: 02/13/2014] [Revised: 05/18/2014] [Accepted: 05/18/2014] [Indexed: 11/15/2022] Open
Abstract
How changes in biodiversity alter the transmission of infectious diseases is presently under debate. Epidemiologists and ecologists have put a lot of effort to understand the mechanism behind biodiversity-disease relationship. Two important mechanisms, i.e. dilution and amplification theories have in some manner made it clear that biodiversity and disease outcome have an intimate relationship. The dilution effect theory seems to answer some overarching questions, but paucity of information about many disease systems is a real obstacle for its acceptance. Also, there is hardly any agreement on host population threshold and critical community size vis-à-vis wild life diseases. We suggest a multidimensional approach whereby the same disease system needs to be studied in different ecological zones and then the effect of biodiversity on disease outcome needs to be ascertained. Nonetheless, caution is to be taken while jumping to any conclusion as biodiversity-disease relationship is a multifactorial process.
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Affiliation(s)
- U R Zargar
- Centre of Research for Development, University of Kashmir, India
| | - M Z Chishti
- Centre of Research for Development, University of Kashmir, India
| | - Fayaz Ahmad
- P.G. Department of Zoology, University of Kashmir, India
| | - M I Rather
- P.G. Department of Environmental Sciences, University of Kashmir, India
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States SL, Brinkerhoff RJ, Carpi G, Steeves TK, Folsom-O'Keefe C, DeVeaux M, Diuk-Wasser MA. Lyme disease risk not amplified in a species-poor vertebrate community: similar Borrelia burgdorferi tick infection prevalence and OspC genotype frequencies. Infect Genet Evol 2014; 27:566-75. [PMID: 24787999 DOI: 10.1016/j.meegid.2014.04.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/29/2014] [Accepted: 04/18/2014] [Indexed: 10/25/2022]
Abstract
The effect of biodiversity declines on human health is currently debated, but empirical assessments are lacking. Lyme disease provides a model system to assess relationships between biodiversity and human disease because the etiologic agent, Borrelia burgdorferi, is transmitted in the United States by the generalist black-legged tick (Ixodes scapularis) among a wide range of mammalian and avian hosts. The 'dilution effect' hypothesis predicts that species-poor host communities dominated by white-footed mice (Peromyscus leucopus) will pose the greatest human risk because P. leucopus infects the largest numbers of ticks, resulting in higher human exposure to infected I. scapularis ticks. P. leucopus-dominated communities are also expected to maintain a higher frequency of those B. burgdorferi outer surface protein C (ospC) genotypes that this host species more efficiently transmits ('multiple niche polymorphism' hypothesis). Because some of these genotypes are human invasive, an additive increase in human disease risk is expected in species-poor settings. We assessed these theoretical predictions by comparing I. scapularis nymphal infection prevalence, density of infected nymphs and B. burgdorferi genotype diversity at sites on Block Island, RI, where P. leucopus dominates the mammalian host community, to species-diverse sites in northeastern Connecticut. We found no support for the dilution effect hypothesis; B. burgdorferi nymphal infection prevalence was similar between island and mainland and the density of B. burgdorferi infected nymphs was higher on the mainland, contrary to what is predicted by the dilution effect hypothesis. Evidence for the multiple niche polymorphism hypothesis was mixed: there was lower ospC genotype diversity at island than mainland sites, but no overrepresentation of genotypes with higher fitness in P. leucopus or that are more invasive in humans. We conclude that other mechanisms explain similar nymphal infection prevalence in both communities and that high ospC genotype diversity can be maintained in both species-poor and species-rich communities.
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Affiliation(s)
- S L States
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA
| | - R J Brinkerhoff
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA; University of Richmond, Department of Biology, 28 Westhampton Way, Richmond, VA 23173, USA; University of KwaZulu-Natal, School of Life Sciences, Pietermaritzburg, South Africa
| | - G Carpi
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA
| | - T K Steeves
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA
| | - C Folsom-O'Keefe
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA; Audubon Connecticut, 185 East Flat Hill Rd., Southbury, CT 06488, USA
| | - M DeVeaux
- Yale School of Public Health, Department of Biostatistics, 60 College Street, New Haven, CT 06520, USA
| | - M A Diuk-Wasser
- Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06520, USA.
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Egizi AM, Farajollahi A, Fonseca DM. Diverse host feeding on nesting birds may limit early-season West Nile virus amplification. Vector Borne Zoonotic Dis 2014; 14:447-53. [PMID: 24745370 DOI: 10.1089/vbz.2013.1536] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [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: 11/13/2022] Open
Abstract
Arboviral activity tracks vector availability, which in temperate regions means that transmission ceases during the winter and must be restarted each spring. In the northeastern United States, Culex restuans Theobald resumes its activity earlier than Culex pipiens L. and is thought to be important in restarting West Nile virus (WNV) transmission. Its role in WNV amplification, however, is unclear, because viral levels commonly remain low until the rise of Cx. pipiens later in the season. Because a vector's feeding habits can reveal key information about disease transmission, we identified early-season (April-June) blood meals from Cx. restuans collected throughout New Jersey, and compared them to published datasets from later in the season and also from other parts of the country. We found significantly higher avian diversity, including poor WNV hosts, and fewer blood meals derived from American Robins (17% versus over 40% found in later season). Critically, we identified blood meals from significantly more female than male birds in species where females are the incubating sex, suggesting that Cx. restuans is able to feed on such a wide variety of hosts in early spring because incubating birds are easy targets. Because WNV amplification depends on virus consistently reaching competent hosts, our results indicate that Cx. restuans is unlikely to be an amplifying vector of WNV in the early season. As the season progresses, however, changes in the availability of nesting birds may make it just as capable as Cx. pipiens, although at somewhat lower abundance as the summer progresses.
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Affiliation(s)
- Andrea M Egizi
- 1 Center for Vector Biology, Rutgers University , Brunswick, New Jersey
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Foley J, Piovia-Scott J. Vector biodiversity did not associate with tick-borne pathogen prevalence in small mammal communities in northern and central California. Ticks Tick Borne Dis 2014; 5:299-304. [PMID: 24582513 DOI: 10.1016/j.ttbdis.2013.12.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [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: 01/12/2013] [Revised: 10/28/2013] [Accepted: 12/02/2013] [Indexed: 11/25/2022]
Abstract
Vector and host abundance affect infection transmission rates, prevalence, and persistence in communities. Biological diversity in hosts and vectors may provide "rescue" hosts which buffer against pathogen extinction and "dilution" hosts which reduce the force of infection in communities. Anaplasma phagocytophilum is a tick-transmitted zoonotic pathogen that circulates in small mammal and tick communities characterized by varying levels of biological diversity. We examined the prevalence of A. phagocytophilum in Ixodes spp. ticks in 11 communities in northern and central California. A total of 1020 ticks of 8 species was evaluated. Five percent of ticks (5 species) were PCR-positive, with the highest prevalence (6-7%) in I. pacificus and I. ochotonae. In most species, adults had a higher prevalence than nymphs or larvae. PCR prevalence varied between 0% and 40% across sites; the infection probability in ticks increased with infestation load and prevalence in small mammals, but not tick species richness, diversity, evenness, or small mammal species richness. No particular tick species was likely to "rescue" infection in the community; rather the risk of A. phagocytophilum infection is related to exposure to particular tick species and life stages, and overall tick abundance.
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Affiliation(s)
- Janet Foley
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA.
| | - Jonah Piovia-Scott
- School of Veterinary Medicine, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA
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Abstract
Isoionic isotope exchange data of 45Ca2+ and 32PO4 3- in a saturated solution with hydroxylapatite at 25 °C, collected by Avnimelech, have been reinterpreted on the basis that the processes consisted of three pools: hydration shell, surface layer and "recrystallization of crystallites." These processes are regarded as strictly separable. This theoretically allows: (i) a quantitative evaluation of the constants involved in the processes; (ii) an estimation of the exchange capacities of hydration and surface layers (fast pools) which may be pH-dependent; and (iii) a determination of the isoionic exchange rate constants. The constants are essentially the same for Ca2+ and PO4 3- at a given pH if the cross-sectional areas of the ions are taken as 23 Å2 and 33 Å2 respectively; they, perhaps, increase linearly with the hydrogen ion concentration of the solutions. The effects of three consecutive abrupt dilutions of the radioactive ions without changing the concentrations (or pH) of the nonradioactive components of the solution are predictable by a mathematical model based on the complete reversibility of the two fast pools and the kinetics of the irreversible third pool.
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Affiliation(s)
- Dwarika Nath Misra
- American Dental Association Health Foundation, Research Unit at the National Bureau of Standards, Washington, DC 20234
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