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Braun L, Sylivester YD, Zerefa MD, Maru M, Allan F, Zewge F, Emery AM, Kinung’hi S, Templeton MR. Chlorination of Schistosoma mansoni cercariae. PLoS Negl Trop Dis 2020; 14:e0008665. [PMID: 32822356 PMCID: PMC7467251 DOI: 10.1371/journal.pntd.0008665] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 09/02/2020] [Accepted: 08/01/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Schistosomiasis is a water-based disease acquired through contact with cercaria-infested water. Communities living in endemic regions often rely on parasite-contaminated freshwater bodies for their daily water contact activities, resulting in recurring schistosomiasis infection. In such instances, water treatment can provide safe water on a household or community scale. However, to-date there are no water treatment guidelines that provide information on how to treat water containing schistosome cercariae. Here, we rigorously test the effectiveness of chlorine against Schistosoma mansoni cercariae. METHOD S. mansoni cercariae were chlorinated using sodium hypochlorite under lab and field condition. The water pH was controlled at 6.5, 7.0 or 7.5, the water temperature at 20°C or 27°C, and the chlorine dose at 1, 2 or 3 mg/l. Experiments were conducted up to contact times of 45 minutes. 100 cercariae were used per experiment, thereby achieving up to 2-log10 inactivations of cercariae. Experiments were replicated under field conditions at Lake Victoria, Tanzania. CONCLUSION A CT (residual chlorine concentration x chlorine contact time) value of 26±4 mg·min/l is required to achieve a 2-log10 inactivation of S. mansoni cercariae under the most conservative condition tested (pH 7.5, 20°C). Field and lab-cultivated cercariae show similar chlorine sensitivities. A CT value of 30 mg·min/l is therefore recommended to disinfect cercaria-infested water, though safety factors may be required, depending on water quality and operating conditions. This CT value can be achieved with a chlorine residual of 1 mg/l after a contact time of 30 minutes, for example. This recommendation can be used to provide safe water for household and recreational water activities in communities that lack safe alternative water sources.
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Affiliation(s)
- Laura Braun
- Department of Civil and Environmental Engineering, South Kensington Campus, Imperial College London, London SW7 2AZ, United Kingdom
| | | | - Meseret Dessalegne Zerefa
- College of Natural and Computational Sciences, Addis Ababa University, Arat Kilo, Addis Ababa, Ethiopia
| | - Muluwork Maru
- College of Natural and Computational Sciences, Addis Ababa University, Arat Kilo, Addis Ababa, Ethiopia
| | - Fiona Allan
- Wolfson Wellcome Biomedical Laboratories, Departssment of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
| | - Feleke Zewge
- College of Natural and Computational Sciences, Addis Ababa University, Arat Kilo, Addis Ababa, Ethiopia
| | - Aidan M. Emery
- Wolfson Wellcome Biomedical Laboratories, Departssment of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
| | - Safari Kinung’hi
- National Institute for Medical Research, Mwanza Center, Isamilo Street, Ilemela, Mwanza, Tanzania
| | - Michael R. Templeton
- Department of Civil and Environmental Engineering, South Kensington Campus, Imperial College London, London SW7 2AZ, United Kingdom
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Hoover CM, Rumschlag SL, Strgar L, Arakala A, Gambhir M, de Leo GA, Sokolow SH, Rohr JR, Remais JV. Effects of agrochemical pollution on schistosomiasis transmission: a systematic review and modelling analysis. Lancet Planet Health 2020; 4:e280-e291. [PMID: 32681899 PMCID: PMC7754781 DOI: 10.1016/s2542-5196(20)30105-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Agrochemical pollution of surface waters is a growing global environmental challenge, especially in areas where agriculture is rapidly expanding and intensifying. Agrochemicals might affect schistosomiasis transmission through direct and indirect effects on Schistosoma parasites, their intermediate snail hosts, snail predators, and snail algal resources. We aimed to review and summarise the effects of these agrochemicals on schistosomiasis transmission dynamics. METHODS We did a systematic review of agrochemical effects on the lifecycle of Schistosoma spp and fitted dose-response models to data regarding the association between components of the lifecycle and agrochemical concentrations. We incorporated these dose-response functions and environmentally relevant concentrations of agrochemicals into a mathematical model to estimate agrochemical effects on schistosomiasis transmission. Dose-response functions were used to estimate individual agrochemical effects on estimates of the agrochemically influenced basic reproduction number, R0, for Schistosoma haematobium. We incorporated time series of environmentally relevant agrochemical concentrations into the model and simulated mass drug administration control efforts in the presence of agrochemicals. FINDINGS We derived 120 dose-response functions describing the effects of agrochemicals on schistosome lifecycle components. The median estimate of the basic reproduction number under agrochemical-free conditions, was 1·65 (IQR 1·47-1·79). Agrochemical effects on estimates of R0 for S haematobium ranged from a median three-times increase (R0 5·05, IQR 4·06-5·97) to transmission elimination (R0 0). Simulations of transmission dynamics subject to interacting annual mass drug administration and agrochemical pollution yielded a median estimate of 64·82 disability-adjusted life-years (DALYs) lost per 100 000 people per year (IQR 62·52-67·68) attributable to atrazine use. In areas where aquatic arthropod predators of intermediate host snails suppress transmission, the insecticides chlorpyrifos (6·82 DALYs lost per 100 000 people per year, IQR 4·13-8·69) and profenofos (103·06 DALYs lost per 100 000 people per year, IQR 89·63-104·90) might also increase the disability burden through their toxic effects on arthropods. INTERPRETATION Expected environmental concentrations of agrochemicals alter schistosomiasis transmission through direct and indirect effects on intermediate host and parasite densities. As industrial agricultural practices expand in areas where schistosomiasis is endemic, strategies to prevent increases in transmission due to agrochemical pollution should be developed and pursued. FUNDING National Science Foundation, National Institutes of Health.
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Affiliation(s)
- Christopher M Hoover
- Division of Environmental Health Sciences, Berkeley School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Samantha L Rumschlag
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Luke Strgar
- Division of Environmental Health Sciences, Berkeley School of Public Health, University of California, Berkeley, Berkeley, CA, USA
| | - Arathi Arakala
- Discipline of Mathematics, School of Sciences, Royal Melbourne Institute of Technology University, Melbourne, VIC, Australia
| | | | - Giulio A de Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA; Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA, USA
| | - Susanne H Sokolow
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA; Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA, USA
| | - Jason R Rohr
- Department of Biological Sciences, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Justin V Remais
- Division of Environmental Health Sciences, Berkeley School of Public Health, University of California, Berkeley, Berkeley, CA, USA.
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Ji CW, Park YS, Cui Y, Wang H, Kwak IS, Chon TS. Analyzing the Response Behavior of Lumbriculus variegatus (Oligochaeta: Lumbriculidae) to Different Concentrations of Copper Sulfate Based on Line Body Shape Detection and a Recurrent Self-Organizing Map. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17082627. [PMID: 32290455 PMCID: PMC7215344 DOI: 10.3390/ijerph17082627] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/07/2020] [Indexed: 11/29/2022]
Abstract
Point detection (e.g., the centroid of the body) of species has been conducted in numerous studies. However, line detection (i.e., the line body shape) of elongated species has rarely been investigated under stressful conditions. We analyzed the line movements of an Oligochaeta Lumbriculus variegatus in response to treatments with a toxic chemical, copper sulfate, at low concentrations (0.01 mg/L and 0.1 mg/L). The automatic line-tracking system was devised to identify the movement of body segments (body length) and the movements of segments (i.e., the speed and angles between segments) were recorded before and after treatment. Total body length was shortened from 31.22 (±5.18) mm to 20.91 (±4.65) mm after the 0.1 mg/L treatment. The Shannon entropy index decreased from 0.44 (±0.1) to 0.28 (±0.08) after treatment. On the other hand, the body and movement segments did not significantly change after the 0.01 mg/L treatment. Sequential movements of test organisms were further analyzed with a recurrent self-organizing map (RSOM) to determine the pattern of time-series line movements. The RSOM made it feasible to classify sequential behaviors of indicator organisms and identify various continuous body movements under stressful conditions.
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Affiliation(s)
- Chang Woo Ji
- Fisheries Science Institute, Chonnam National University, Yeosu 59626, Korea; (C.W.J.); (I.-S.K.)
| | - Young-Seuk Park
- Department of Biology and Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 02447, Korea
- Correspondence: (Y.-S.P.); (T.-S.C.); Tel.: +82-2-961-0946 (Y.-S.P.); +82-51-512-2262 (T.-S.C.)
| | - Yongde Cui
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (H.W.)
| | - Hongzhu Wang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; (Y.C.); (H.W.)
| | - Ihn-Sil Kwak
- Fisheries Science Institute, Chonnam National University, Yeosu 59626, Korea; (C.W.J.); (I.-S.K.)
| | - Tae-Soo Chon
- Ecology and Future Research Association (EnFRA), Dusil-ro 45 beon-gil 21, Geumjeong-gu, Busan 46228, Korea
- Correspondence: (Y.-S.P.); (T.-S.C.); Tel.: +82-2-961-0946 (Y.-S.P.); +82-51-512-2262 (T.-S.C.)
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Monde C, Syampungani S, Van den Brink PJ. Effects of Endosulfan on Predator-Prey Interactions Between Catfish and Schistosoma Host Snails. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2016; 71:257-66. [PMID: 27033099 PMCID: PMC4935736 DOI: 10.1007/s00244-016-0275-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/18/2016] [Indexed: 06/05/2023]
Abstract
The effect of the pesticide endosulfan on predator-prey interactions between catfish and Schistosoma host snails was assessed in static tank experiments. Hybrid catfish (Clarias gariepinus × C. ngamensis) and Bulinus globosus were subjected to various endosulfan concentrations including an untreated control. The 48- and 96-h LC50 values for catfish were 1.0 and <0.5 µg/L, respectively, whereas the 48- and 96-h LC50 values for snails were 1137 and 810 µg/L. To assess sublethal effects on the feeding of the catfish on B. globosus, endosulfan concentrations between 0.03 and 1.0 µg/L were used. Predation was significantly greater (p < 0.001) in control tanks than in all other treatments. There was progressively decreasing predation with increasing toxicant concentration. Biological control of Schistosoma host snails using fish may be affected in endosulfan-polluted aquatic systems of Southern Africa because it has been found present at concentrations that are indicated to cause lethal effects on the evaluated hybrid catfish and to inhibit the predation of snails by this hybrid catfish.
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Affiliation(s)
- Concillia Monde
- Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research Centre, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
- Department of Zoology and Aquatic Sciences, Copperbelt University, Jambo Drive, Riverside, P.O. Box 21692, Kitwe, Zambia.
| | - Stephen Syampungani
- Department of Plant and Environmental Sciences, Copperbelt University, Jambo Drive, Riverside, P.O Box 21692, Kitwe, Zambia
| | - Paul J Van den Brink
- Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research Centre, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
- Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
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Wang L, Ren Z, Kim H, Xia C, Fu R, Chon TS. Characterizing response behavior of medaka ( Oryzias latipes ) under chemical stress based on self-organizing map and filtering by integration. ECOL INFORM 2015. [DOI: 10.1016/j.ecoinf.2014.11.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Liu Y, Wu F, Ji C, Chon T. Movement Patterning of Daphnia magna Treated with Copper Based on Self-Organizing Map. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.proenv.2012.01.092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Koprivnikar J, Walker PA. Effects of the herbicide atrazine's metabolites on host snail mortality and production of trematode cercariae. J Parasitol 2011; 97:822-7. [PMID: 21554070 DOI: 10.1645/ge-2814.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Environmental stressors have the potential to greatly impact the transmission of parasites with complex, multi-host life cycles such as those of trematodes. The commonly used herbicide atrazine has been shown to affect the susceptibility of second intermediate hosts (such as larval amphibians) to trematode infection, as well as the longevity and infectivity of the free-swimming cercariae, but not eggs or the free-swimming miracidia that infect the gastropod first intermediate hosts. However, we do not know if this pesticide influences the survival of infected snails or whether it affects cercariae production within, or emergence from, these hosts. In addition, previous studies of host-parasite dynamics have only examined the parent atrazine compound, not any of the long-lasting metabolites commonly present in water bodies. Here, we report that a concentration of 0.33 µg/L of an atrazine metabolite, desethyl atrazine, increased the mortality of freshwater gastropods ( Stagnicola elodes ) infected with a gymnocephalus type of cercaria but not that of uninfected snails or those harboring a mature or dormant infection of Echinoparyphium sp. In contrast, 2 wk of exposure to desethyl atrazine did not affect the emergence of gymnocephalus cercariae from snails, although a trend for a decrease in the emergence of Echinoparyphium sp. cercariae was observed. We suggest that simultaneous trematode infection and exposure to contaminants may represent a significant combined stress to gastropods, but this is likely parasite species-specific as well as dependent on whether cercariae are being actively produced.
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Affiliation(s)
- Janet Koprivnikar
- Department of Biology, Brandon University, 270 18th Street, Brandon, Manitoba, Canada.
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Koprivnikar J, Baker RL, Forbes MR. Environmental factors influencing community composition of gastropods and their trematode parasites in southern Ontario. J Parasitol 2008; 93:992-8. [PMID: 18163331 DOI: 10.1645/ge-1144r.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Agricultural activity and landscape features have previously been associated with diversity and prevalence of trematode species in amphibian second intermediate hosts. In this study, the density, diversity, and size of snail first intermediate hosts, and the diversity and prevalence of their trematode species, were assessed in 2 types of ponds, i.e., those adjacent to cornfields and those from the same region in southwestern Ontario that were adjacent to nonagricultural settings. Species of trematodes included, but were not restricted to, those that are known parasites of larval and adult frogs. We also assessed landscape factors likely to influence use by definitive hosts. Presence of the herbicide atrazine in ponds was measured to check that ponds adjacent to agriculture had potential to be affected by agricultural runoff. Both snail size and the proportion of snails releasing cercariae were greater in nonagricultural ponds, contrasting with a previous finding of lower trematode infection in tadpoles from nonagricultural ponds. Percentage of forest cover was associated with prevalence of certain trematode species, but not with estimates of combined prevalence. Absence of relations of trematode prevalence to measures of road density also contrasted with previous studies. We interpret our results in light of how agricultural activity might influence trematode viability, snail growth, and use by wildlife definitive hosts, independently of landscape factors.
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Affiliation(s)
- Janet Koprivnikar
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
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Morley NJ, Lewis JW, Hoole D. Pollutant-induced effects on immunological and physiological interactions in aquatic host–trematode systems: implications for parasite transmission. J Helminthol 2007; 80:137-49. [PMID: 16768857 DOI: 10.1079/joh2006345] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
AbstractUnder conditions of pollution both host and parasite are susceptible to the pathogenic effects of toxicants, which in turn may result in detrimental changes to their immunological and physiological processes. Digenetic trematodes, which encompass species of both medical and economic importance, possess complex life cycles and are common parasites of both vertebrates and molluscs. The combined stress induced by pollution and parasitism influences the physiology of the host which can have implications not only on host survival but also on the functional biology of resident parasite populations. The present paper reviews the effects of pollutants on the immunology and physiology in both vertebrate and molluscan host–trematode systems and the implications for parasite transmission.
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Affiliation(s)
- N J Morley
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK.
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Morley NJ, Crane M, Lewis JW. Changes in survival characteristics ofDiplostomum spathaceumcercariae emerged from cadmium-exposedLymnaea stagnalis. J Helminthol 2007; 79:55-9. [PMID: 15831114 DOI: 10.1079/joh2004271] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe effect of exposingLymnaea stagnalis(Gastropoda: Pulmonata), infected withDiplostomum spathaceum(Trematoda: Diplostomatidae), to 100 μg l−1cadmium for 7 days on survival characteristics (survival, tail loss, decaudized cercarial life-span) of emerged cercariae was investigated. Exposure ofL. stagnalisto cadmium resulted in significantly increasedD. spathaceumcercarial survival and an inhibited tail loss compared to controls. The normal parallel relationship which exists over time between decreasing cercarial survival and increasing tail loss in controls was changed in cercariae from cadmium-exposed hosts with an increased proportion of cercarial deaths occurring without tail loss. The decaudized cercarial life-span over the survival period of the cercarial population did not significantly change. However comparisons between individuals decaudized during the initial 24 h time period with those which were decaudized during the final period of cercarial survival showed a significantly altered life span which did not occur in the control population. As a potential indicator of penetration ‘fitness’ comparisons were also undertaken between control and exposed cercariae decaudized during the initial 24 h time period, which revealed that the decaudized cercarial life-span from the exposed hosts was significantly different from controls. This may have important implications for the ability of cercariae to migrate through the tissues of their target host. The importance and relevance of these results to parasite transmission are discussed.
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Affiliation(s)
- N J Morley
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK.
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Abstract
The field of ecotoxicology is experiencing a surge in attention among ecologists as we gain a deeper appreciation for how contaminants can impact natural ecosystems. This interest is particularly strong in aquatic systems where many non-target organisms experience pesticides. In this article, we assess how pesticides affect freshwater systems by applying the conceptual framework of density- and trait-mediated indirect effects from the field of basic ecology. We demonstrate the utility of this framework for understanding the conditions under which pesticides affect species interactions, communities and ecosystems. Through the integration of laboratory toxicity tests and this ecological framework, ecotoxicologists should be better able to identify the mechanisms through which pesticides affect communities and ecosystems. We also identify several areas of research that are in critical need of empirical attention including synergistic effects between pesticides and natural stressors, the importance of pesticides on community assembly via habitat preferences and oviposition effects, the timing and frequency of pesticide applications, pesticide effects on population dynamics, the evolution of pesticide resistance in non-target organisms and ecosystem recovery. With this knowledge, one can improve upon management decisions and help protect non-target species that are of conservation concern.
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Affiliation(s)
- Rick Relyea
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Kim CK, Kwak IS, Cha EY, Chon TS. Implementation of wavelets and artificial neural networks to detection of toxic response behavior of chironomids (Chironomidae: Diptera) for water quality monitoring. Ecol Modell 2006. [DOI: 10.1016/j.ecolmodel.2005.11.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Morley NJ, Irwin SWB, Lewis JW. Pollution toxicity to the transmission of larval digeneans through their molluscan hosts. Parasitology 2004; 126 Suppl:S5-26. [PMID: 14667169 DOI: 10.1017/s0031182003003755] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The increased occurrence of pollutants in ecosystems is a continuing area of concern. It is known that numerous diseases of wild aquatic animals can occur with decreased or increased prevalences in areas associated with high or chronic levels of pollution. This may have serious implications for environmental health. There has consequently been an increasing number of laboratory and field studies on disease transmission under polluted conditions, especially focusing on digeneans of medical or economic importance. The effect of pollutants to the transmission of larval digeneans (miracidia, cercariae, metacercariae) and snail-digenean interactions is therefore considered. An overview and interpretation of the published literature on laboratory and field studies is provided. It is apparent from these studies that the influence of pollutants on digenean transmission is highly complex with much of the observed effects in the laboratory often masked by a complexity of other factors in the field. Future studies would benefit from a standardisation of experimental procedures, increasing the number of combined laboratory and field studies, and increasing the complexity of the experiments undertaken.
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Affiliation(s)
- N J Morley
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK.
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Kwak IS, Chon TS, Kang HM, Chung NI, Kim JS, Koh SC, Lee SK, Kim YS. Pattern recognition of the movement tracks of medaka (Oryzias latipes) in response to sub-lethal treatments of an insecticide by using artificial neural networks. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2002; 120:671-681. [PMID: 12442790 DOI: 10.1016/s0269-7491(02)00183-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Specimens of medaka (Oryzias latipes) were observed continuously through an automatic image recognition system before and after treatments of an anti-cholinesterase insecticide, diazinon (0.1 mg/l), for 4 days in semi-natural conditions (2 days before treatment and 2 days after treatment). The "smooth" pattern was typically shown as a normal movement behavior, while the "shaking" pattern was frequently observed after treatments of diazinon. These smooth and shaking patterns were selected for training with an artificial neural network. Parameters characterizing the movement tracks, such as speed, degree of backward movements, stop duration, turning rate, meander, and maximum distance movements in the y-axis of 1-min duration, were given as input (six nodes) to a multi-layer perceptron with the back propagation algorithm. Binary information for the smooth and shaking patterns was separately given as the matching output (one node), while eight nodes were assigned to a single hidden layer. As new input data were given to the trained network, it was possible to recognize the smooth and shaking patterns of the new input data. Average recognition rates of the smooth pattern decreased significantly while those for the shaking pattern increased to a higher degree after treatments of diazinon. The trained network was able to reveal the difference in the shaking pattern in different light phases before treatments of diazinon. This study demonstrated that artificial neural networks could be useful for detecting the presence of toxic chemicals in the environment by serving as in-situ behavioral monitoring tools.
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Affiliation(s)
- Inn-Sil Kwak
- Division of Biological Sciences, Pusan National University, South Korea
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Davies RW, Singhal RN, Wicklum DD. Changes in reproductive potential of the leech Nephelopsis obscura (Erpobdellidae) as biomarkers for cadmium stress. CAN J ZOOL 1995. [DOI: 10.1139/z95-259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of exposure for 4–24 days to 0, 58, 145, 290, 435, and 580 μg∙L−1 cadmium on the reproductive potential of the freshwater predatory leech Nephelopsis obscura were investigated. The numbers of ova and spermatozoa per unit biomass were significantly reduced with increasing cadmium concentration and exposure time, as were the masses of the ovisacs, testisacs, and epididymis plus cornu. It is concluded that these variables are effective biomarkers for identifying sublethal effects of direct importance to population dynamics.
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Barron MG, Woodburn KB. Ecotoxicology of chlorpyrifos. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 1995; 144:1-93. [PMID: 8599033 DOI: 10.1007/978-1-4612-2550-8_1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Chlorpyrifos is a broad-spectrum organophosphorothioate insecticide with a principal mechanism of toxicity by inactivation of acetylcholinesterase at nerve junctions. Unlike certain organochlorine pesticides, chlorpyrifos is relatively nonpersistent (Racke 1993), and its principal degradation products are less toxic than the parent chemical. Species sensitivity varies considerably across kingdom and phyla. In general, aquatic and terrestrial microorganisms and plants are tolerant to chlorpyrifos exposure. Aquatic invertebrates, particularly crustaceans and insect larvae, are sensitive to exposure: LC50s are generally less than 1 microgram/L, and no-observed-effect concentrations may be below 0.1 microgram/L in laboratory studies. Fish appear to be less sensitive, with LC50s generally between 1 and 100 micrograms/L and no-observed effect concentrations of approximately 0.5 microgram/L. In general, saltwater and freshwater organisms exhibit similar sensitivity to chlorpyrifos, considering the extreme phylogenetic and species differences in toxicity. Chlorpyrifos effects in aquatic ecosystems are complex because of the diversity of species assemblages and trophic interactions. In general, functional endpoints (e.g., community metabolism) are less sensitive than structural parameters of ecosystems (e.g., loss of sensitive species). Ecosystem recovery is dependent on the interaction of a variety of factors including treatment timing and application dose, rate of dissipation, species assemblages, trophic structure, and the reproductive capacity and growth rate of susceptible and tolerant populations. Terrestrial species are relatively tolerant of chlorpyrifos exposure, although contact toxicity to sensitive terrestrial invertebrates may occur at concentrations of 0.1 microgram/insect. Amphibians, birds, and mammals show similar sensitivity to orally administered chlorpyrifos, with LD50s ranging from 8 to > 400 mg/kg body weight. Long-term chronic feeding studies in birds and mammals have shown no observed effect concentrations to be greater than 1 mg/kg food. In general, field studies have shown limited or no acute toxicity to amphibians, reptiles, birds, or mammals.
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Affiliation(s)
- M G Barron
- Hagler Bailly Consulting Inc., Boulder, CO 80306-1906, USA
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