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Doyle SR, Søe MJ, Nejsum P, Betson M, Cooper PJ, Peng L, Zhu XQ, Sanchez A, Matamoros G, Sandoval GAF, Cutillas C, Tchuenté LAT, Mekonnen Z, Ame SM, Namwanje H, Levecke B, Berriman M, Fredensborg BL, Kapel CMO. Population genomics of ancient and modern Trichuris trichiura. Nat Commun 2022; 13:3888. [PMID: 35794092 PMCID: PMC9259628 DOI: 10.1038/s41467-022-31487-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 06/17/2022] [Indexed: 11/14/2022] Open
Abstract
The neglected tropical disease trichuriasis is caused by the whipworm Trichuris trichiura, a soil-transmitted helminth that has infected humans for millennia. Today, T. trichiura infects as many as 500 million people, predominantly in communities with poor sanitary infrastructure enabling sustained faecal-oral transmission. Using whole-genome sequencing of geographically distributed worms collected from human and other primate hosts, together with ancient samples preserved in archaeologically-defined latrines and deposits dated up to one thousand years old, we present the first population genomics study of T. trichiura. We describe the continent-scale genetic structure between whipworms infecting humans and baboons relative to those infecting other primates. Admixture and population demographic analyses support a stepwise distribution of genetic variation that is highest in Uganda, consistent with an African origin and subsequent translocation with human migration. Finally, genome-wide analyses between human samples and between human and non-human primate samples reveal local regions of genetic differentiation between geographically distinct populations. These data provide insight into zoonotic reservoirs of human-infective T. trichiura and will support future efforts toward the implementation of genomic epidemiology of this globally important helminth.
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Affiliation(s)
| | - Martin Jensen Søe
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Peter Nejsum
- Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark
| | - Martha Betson
- School of Veterinary Medicine, University of Surrey, Guildford, UK
| | - Philip J Cooper
- Institute of Infection and Immunity, St George's University of London, London, UK
- School of Medicine, Universidad Internacional del Ecuador, Quito, Ecuador
| | - Lifei Peng
- Department of Parasitology, School of Basic Medical Sciences, Guangdong Medical University, Zhanjiang, Guangdong Province, People's Republic of China
| | - Xing-Quan Zhu
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, People's Republic of China
| | - Ana Sanchez
- Department of Health Sciences, Brock University, St. Catharines, Ontario, Canada
| | - Gabriela Matamoros
- Microbiology Research Institute, Ciudad Universitaria, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras
| | | | - Cristina Cutillas
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain
| | | | - Zeleke Mekonnen
- Institute of Health, School of Medical Laboratory Sciences, Jimma University, Jimma, Ethiopia
| | - Shaali M Ame
- Public Health Laboratory Ivo de Carneri, Pemba, Tanzania
| | | | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Ghent, Belgium
| | | | - Brian Lund Fredensborg
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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2
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Mkandawire TT, Grencis RK, Berriman M, Duque-Correa MA. Hatching of parasitic nematode eggs: a crucial step determining infection. Trends Parasitol 2022; 38:174-187. [PMID: 34538735 DOI: 10.1016/j.pt.2021.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 08/22/2021] [Accepted: 08/26/2021] [Indexed: 11/30/2022]
Abstract
Although hatching from eggs is fundamental for nematode biology it remains poorly understood. For animal-parasitic nematodes in particular, advancement has been slow since the 1980s. Understanding such a crucial life-cycle process would greatly improve the tractability of parasitic nematodes as experimental systems, advance fundamental knowledge, and enable translational research. Here, we review the role of eggs in the nematode life cycle and the current knowledge on the hatching cascade, including the different inducing and contributing factors, and highlight specific areas of the field that remain unknown. We examine how these knowledge gaps could be addressed and discuss their potential impact and application in nematode parasite research, treatment, and control.
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Affiliation(s)
| | - Richard K Grencis
- The Lydia Becker Institute of Immunology and Inflammation, Wellcome Trust Centre for Cell Matrix Research and Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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3
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Forman R, Partridge FA, Sattelle DB, Else KJ. Un-‘Egg’-Plored: Characterisation of Embryonation in the Whipworm Model Organism Trichuris muris. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.790311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Trichuris muris, is the murine parasite and widely deployed model for the human whipworm Trichuris trichiura, a parasite that infects around 500 million people globally. Trichuriasis is a classical disease of poverty with a cycle of re-infection due to the continual exposure of humans, particularly children, to infective eggs, which contaminate the soil in endemic areas. Indeed, modelling studies of trichuriasis have demonstrated that the low efficacy rate of current anthelmintics combined with the high possibility of re-infection from the reservoir of infective eggs within the environment, mean that the elimination of morbidity due to trichuriasis is unlikely to occur. Despite the importance of the infective egg stage in the perpetuation of infections, understanding the biology of the Trichuris ova has been neglected for decades. Here we perform experiments to assess the impact of temperature on the embryonation process of T. muris eggs and describe in detail the stages of larval development within these eggs. In keeping with the early works performed in the early 1900s, we show that the embryonation of T. muris is accelerated by an elevation in temperature, up to 37°C above which eggs do not fully develop and become degenerate. We extend these data to provide a detailed description of T. muris egg development with clear images depicting the various stages of development. To the best of our knowledge we have, for the first time, described the presence of birefringent granules within egg-stage larvae, as well as providing a qualitative and quantitative description of a motile larval stage prior to quiescence within the egg. These experiments are the first step towards a better understanding of the basic biology which underlies the process of egg embryonation. With the threat of elevation in global temperatures, the accelerated embryonation rate we observe at higher temperatures may have important consequences for parasite transmission rates and prospective modelling studies. In addition, a deeper understanding of the Trichuris ova may allow the development of novel control strategies targeting the egg stage of Trichuris in the environment as an adjunct to MDA.
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4
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Mair I, Else KJ, Forman R. Trichuris muris as a tool for holistic discovery research: from translational research to environmental bio-tagging. Parasitology 2021; 148:1-13. [PMID: 33952360 PMCID: PMC8660646 DOI: 10.1017/s003118202100069x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/11/2022]
Abstract
Trichuris spp. (whipworms) are intestinal nematode parasites which cause chronic infections associated with significant morbidities. Trichuris muris in a mouse is the most well studied of the whipworms and research on this species has been approached from a number of different disciplines. Research on T. muris in a laboratory mouse has provided vital insights into the host–parasite interaction through analyses of the immune responses to infection, identifying factors underpinning host susceptibility and resistance. Laboratory studies have also informed strategies for disease control through anthelmintics and vaccine research. On the contrary, research on naturally occurring infections with Trichuris spp. allows the analysis of the host–parasite co-evolutionary relationships and parasite genetic diversity. Furthermore, ecological studies utilizing Trichuris have aided our knowledge of the intricate relationships amongst parasite, host and environment. More recently, studies in wild and semi-wild settings have combined the strengths of the model organism of the house mouse with the complexities of context-dependent physiological responses to infection. This review celebrates the extraordinarily broad range of beneficiaries of whipworm research, from immunologists and parasitologists, through epidemiologists, ecologists and evolutionary biologists to the veterinary and medical communities.
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Affiliation(s)
- Iris Mair
- Faculty of Biology, Medicine and Health, Lydia Becker Institute of Immunology and Inflammation, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, ManchesterM13 9PT, UK
| | - Kathryn J. Else
- Faculty of Biology, Medicine and Health, Lydia Becker Institute of Immunology and Inflammation, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, ManchesterM13 9PT, UK
| | - Ruth Forman
- Faculty of Biology, Medicine and Health, Lydia Becker Institute of Immunology and Inflammation, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, ManchesterM13 9PT, UK
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5
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Stracke K, Adisakwattana P, Phuanukoonnon S, Yoonuan T, Poodeepiyasawat A, Dekumyoy P, Chaisiri K, Roth Schulze A, Wilcox S, Karunajeewa H, Traub RJ, Jex AR. Effective low-cost preservation of human stools in field-based studies for helminth and microbiota analysis. Int J Parasitol 2021; 51:741-748. [PMID: 33774039 DOI: 10.1016/j.ijpara.2021.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/19/2022]
Abstract
Molecular studies of gastrointestinal infections or microbiotas require either rapid sample processing or effective interim preservation. This is difficult in remote settings in low-income countries, where the majority of the global infectious disease burden exists. Processing or freezing of samples immediately upon collection is often not feasible and the cost of commercial preservatives is prohibitive. We compared fresh freezing (the 'gold standard' method), with low-cost chemical preservation in (i) a salt-based buffer consisting of DMSO, EDTA and NaCl (DESS) or (ii) 2.5% potassium dichromate (PD), for soil-transmitted helminth detection and microbiota characterisation in pre-school and school-aged children from north-western Thailand. Fresh frozen samples were frozen at -20°C on collection and maintained at -80°C within ~3 days of collection until molecular analysis, with international shipping on dry ice. In contrast, chemically preserved samples were collected and stored at ~4°C, transported on wet ice and only stored at -20°C on arrival in Australia ~8 weeks after collection, with international shipping on wet ice. DESS and PD provided better sensitivity for STH diagnosis, estimating higher infection rates (>80% for Ascaris lumbricoides and >60% for Trichuris trichiura; versus 56% and 15% for these parasites in fresh frozen samples) and egg abundance (inferred as gene copy number estimates). All methods performed similarly for microbiota preservation, showing no significant differences in alpha-diversity based on overall richness or inverted Simpson's Index. All three methods performed similarly for RNA and protein preservation in a small subset of samples. Overall, DESS provided the best performance, with the added benefit of being non-toxic, compared with PD, hence making it particularly applicable for studies in remote and resource-poor settings.
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Affiliation(s)
- Katharina Stracke
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Department of Medical Biology, The Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia.
| | - Poom Adisakwattana
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Suparat Phuanukoonnon
- Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tippayarat Yoonuan
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Akkarin Poodeepiyasawat
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paron Dekumyoy
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kittipong Chaisiri
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Stephen Wilcox
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Harin Karunajeewa
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Department of Medicine - Western Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Rebecca J Traub
- Faculty for Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Aaron R Jex
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Faculty for Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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Souza MV, Chaves SAM, Iñiguez AM. New observations from the intestinal fauna of Kerodon rupestris (Wied, 1820) (Rodentia, Cavidae), Brazil: a checklist spanning 30,000 years of parasitism. BRAZ J BIOL 2020; 81:989-998. [PMID: 33111930 DOI: 10.1590/1519-6984.232838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/22/2020] [Indexed: 02/01/2023] Open
Abstract
This checklist of parasites of Kerodon rupestris, an endemic rodent from the Brazilian semiarid region, revealed records of 25 enteroparasite taxa comprising Cestoda (Anoplocephalidae), Trematoda, Acanthocephala and Nematoda (Ancylostomidae, Ascarididae, Heterakidae, Oxyuridae, Pharyngodonidae, Trichuridae, Capillariidae, Trichostrongylidae, and Strongyloididae), and two taxa of coccidian. Paleoparasitological and parasitological studies published until 2019 were assessed in the present study and locality information, site of infection, sample dating, and host data were summarized from each reference. Analyses of recent feces and coprolites revealed the highest species richness in the Piauí State. The chronological data corroborated that Trichuris spp. and oxyurids are part of the parasitic fauna of K. rupestris. This represents the first checklist of intestinal parasites from K. rupestris.
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Affiliation(s)
- M V Souza
- Instituto Oswaldo Cruz, Fundação Oswaldo Cruz-Fiocruz, Laboratório de Tripanosomatídeos - LABTRIP, Rio de Janeiro, RJ., Brasil.,Fundação Oswaldo Cruz-Fiocruz, Escola Nacional de Saúde Pública Sérgio Arouca, Laboratório de Palinologia/Ecologia, Rio de Janeiro, RJ, Brasil
| | - S A M Chaves
- Fundação Oswaldo Cruz-Fiocruz, Escola Nacional de Saúde Pública Sérgio Arouca, Laboratório de Palinologia/Ecologia, Rio de Janeiro, RJ, Brasil
| | - A M Iñiguez
- Instituto Oswaldo Cruz, Fundação Oswaldo Cruz-Fiocruz, Laboratório de Tripanosomatídeos - LABTRIP, Rio de Janeiro, RJ., Brasil
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7
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Choi JH, Park SK, Park MK, Kang SA, Lee D, Song SM, Kim HJ, Park SH, Kim EM, Yu HS. An advanced protocol for the purification of whipworm eggs from feces for use as therapeutic agents. Parasitol Int 2019; 70:41-45. [PMID: 30716463 DOI: 10.1016/j.parint.2019.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 01/31/2019] [Accepted: 01/31/2019] [Indexed: 01/03/2023]
Abstract
Recent studies have attempted to treat autoimmune diseases using Trichuris suis. whipworm) eggs. Large quantities of eggs can be obtained efficiently by collecting from the feces of the porcine hosts rather than by extracting from the female worm uterus. However, it is difficult to process large amounts of feces using the current methods. In the present study, we propose a method to collect the eggs from bulk feces more efficiently. Collecting the eggs using washing meshes (25 μm sieve) yields 65.7% (56.0-70.7) of eggs (median, min-max) from 100 g feces. Our method, which uses ethyl acetate and simulated gastric fluid, yielded 91.4% (91.4-94.0) of the eggs from 100 g feces into the separated aqueous solution. Egg collection using simulated gastric fluid (SGF) method was also 60 min faster than that using the sieve method. As the SGF used in the experiment is a strongly acidic reagent with a pH of 1-2, embryonation of the eggs was induced by the rapid pH change. As a result, 37.1% (8.0-77.8) of the eggs had embryonated two months after SGF stimulation. Using the developed method, we could process the feces quickly and efficiently. Furthermore, after purification, egg embryonation could be induced without any harmful reagent treatment. This method is expected to be helpful for further research using Trichuris suis eggs.
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Affiliation(s)
- Jun Ho Choi
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - Sang Kyun Park
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - Mi Kyung Park
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - Shin Ae Kang
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - Dain Lee
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - So Myong Song
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - Hye Jin Kim
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - Sung Hee Park
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea
| | - Eun-Min Kim
- Department of Environmental Medical Biology and Arthropods of Medical Importance Resource Research Bank, Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Hak Sun Yu
- Department of Parasitology, School of Medicine, Pusan National University, Immunoregulatory Therapeutics group in Brain Busan 21 project, Republic of Korea.
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8
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Partridge FA, Forman R, Willis NJ, Bataille CJR, Murphy EA, Brown AE, Heyer-Chauhan N, Marinič B, Sowood DJC, Wynne GM, Else KJ, Russell AJ, Sattelle DB. 2,4-Diaminothieno[3,2-d]pyrimidines, a new class of anthelmintic with activity against adult and egg stages of whipworm. PLoS Negl Trop Dis 2018; 12:e0006487. [PMID: 29995893 PMCID: PMC6062138 DOI: 10.1371/journal.pntd.0006487] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 07/26/2018] [Accepted: 05/01/2018] [Indexed: 11/29/2022] Open
Abstract
The human whipworm Trichuris trichiura is a parasite that infects around 500 million people globally, with consequences including damage to physical growth and educational performance. Current drugs such as mebendazole have a notable lack of efficacy against whipworm, compared to other soil-transmitted helminths. Mass drug administration programs are therefore unlikely to achieve eradication and new treatments for trichuriasis are desperately needed. All current drug control strategies focus on post-infection eradication, targeting the parasite in vivo. Here we propose developing novel anthelmintics which target the egg stage of the parasite in the soil as an adjunct environmental strategy. As evidence in support of such an approach we describe the actions of a new class of anthelmintic compounds, the 2,4-diaminothieno[3,2-d]pyrimidines (DATPs). This compound class has found broad utility in medicinal chemistry, but has not previously been described as having anthelmintic activity. Importantly, these compounds show efficacy against not only the adult parasite, but also both the embryonated and unembryonated egg stages and thereby may enable a break in the parasite lifecycle. The human whipworm, Trichuris trichiura, infects around 500 million people globally, impacting on their physical growth and educational performance. There are currently huge mass drug administration (MDA) programs aiming to control whipworm, along with the other major soil transmitted helminths, Ascaris and hookworm. However single doses of albendazole and mebendazole, which are used in MDA, have particularly poor effectiveness against whipworm, with cure rates less than 40%. This means that MDA may not be able to control and eliminate whipworm infection, and risks the spread of resistance to albendazole and mebendazole in the parasite population. We are attempting to develop new treatments for parasitic worm infection, particularly focused on whipworm. We report the identification of a class of compounds, diaminothienopyrimidines (DATPs), which have not previously been described as anthelmintics. These compounds are effective against adult stages of whipworm, and also block the development of the model nematode C. elegans. Our DATP compounds reduce the ability of treated eggs to successfully establish infection in a mouse model of human whipworm. These results support a potential environmental spray to control whipworm by targeting the infectious egg stage in environmental hotspots.
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Affiliation(s)
- Frederick A. Partridge
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, London, United Kingdom
| | - Ruth Forman
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Nicky J. Willis
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Carole J. R. Bataille
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Emma A. Murphy
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Anwen E. Brown
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, London, United Kingdom
| | - Narinder Heyer-Chauhan
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, London, United Kingdom
| | - Bruno Marinič
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Daniel J. C. Sowood
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Graham M. Wynne
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Kathryn J. Else
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- * E-mail: (DBS); (KJE); (AJR)
| | - Angela J. Russell
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
- * E-mail: (DBS); (KJE); (AJR)
| | - David B. Sattelle
- Centre for Respiratory Biology, UCL Respiratory, Division of Medicine, University College London, London, United Kingdom
- * E-mail: (DBS); (KJE); (AJR)
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9
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Abstract
Climate change is expected to impact across every domain of society, including health. The majority of the world's population is susceptible to pathological, infectious disease whose life cycles are sensitive to environmental factors across different physical phases including air, water and soil. Nearly all so-called neglected tropical diseases (NTDs) fall into this category, meaning that future geographic patterns of transmission of dozens of infections are likely to be affected by climate change over the short (seasonal), medium (annual) and long (decadal) term. This review offers an introduction into the terms and processes deployed in modelling climate change and reviews the state of the art in terms of research into how climate change may affect future transmission of NTDs. The 34 infections included in this chapter are drawn from the WHO NTD list and the WHO blueprint list of priority diseases. For the majority of infections, some evidence is available of which environmental factors contribute to the population biology of parasites, vectors and zoonotic hosts. There is a general paucity of published research on the potential effects of decadal climate change, with some exceptions, mainly in vector-borne diseases.
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Affiliation(s)
- Mark Booth
- Newcastle University, Institute of Health and Society, Newcastle upon Tyne, United Kingdom.
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10
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Martins ML, Watral V, Rodrigues-Soares JP, Kent ML. A method for collecting eggs of Pseudocapillaria tomentosa (Nematoda: Capillariidae) from zebrafish Danio rerio and efficacy of heat and chlorine for killing the nematode's eggs. JOURNAL OF FISH DISEASES 2017; 40:169-182. [PMID: 27334246 PMCID: PMC5182181 DOI: 10.1111/jfd.12501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/15/2016] [Accepted: 04/15/2016] [Indexed: 05/04/2023]
Abstract
Pseudocapillaria tomentosa is a common pathogen of zebrafish (Danio rerio) in research facilities. We developed a method to collect and concentrate the nematode eggs using a modified sugar centrifugation method and documented their normal development. Embryonating stages with blastomere formation followed by elongation of the embryo prior to larva formation cumulated in developed larvae inside the eggs and hatching after 5-10 day. We then evaluated the efficacy of heat and chlorine to kill them based on a larva development assay. Eggs were exposed to 40, 50, 60 °C for 30 min and 1 h. Chlorine treatment was performed at 100, 250, 500, 1000, 3000 and 6000 ppm for 10 min. Samples exposed to 40 °C for 30 min or 1 h showed incidences of larvated eggs similar to controls. In contrast, no larvation occurred with eggs exposed to either 50 or 60 °C for 30 min or 1 h. Remarkably, in repeated assays, samples exposed to low doses of chlorine (100, 250, 500 and 1000 ppm for 10 min) showed significantly higher incidence of larvation than controls. Eggs treated with 3000 ppm for 10 min did not develop larvae, and no eggs were found after 6000 ppm treatment.
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Affiliation(s)
- ML Martins
- AQUOS - Aquatic Organism Health Laboratory, Aquaculture Department, Federal University of Santa Catarina (UFSC), Rod. Admar Gonzaga 1346, 88040-900, Florianopolis, SC, Brazil
- Departments of Microbiology and Biomedical Sciences, Oregon State University, 97331, Corvallis, OR, USA
| | - V Watral
- Departments of Microbiology and Biomedical Sciences, Oregon State University, 97331, Corvallis, OR, USA
| | - JP Rodrigues-Soares
- AQUOS - Aquatic Organism Health Laboratory, Aquaculture Department, Federal University of Santa Catarina (UFSC), Rod. Admar Gonzaga 1346, 88040-900, Florianopolis, SC, Brazil
| | - ML Kent
- Departments of Microbiology and Biomedical Sciences, Oregon State University, 97331, Corvallis, OR, USA
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