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Zhao X, Liu Y, Guo YM, Xu C, Chen L, Codd GA, Chen J, Wang Y, Wang PZ, Yang LW, Zhou L, Li Y, Xiao SM, Wang HJ, Paerl HW, Jeppesen E, Xie P. Meta-analysis reveals cyanotoxins risk across African inland waters. JOURNAL OF HAZARDOUS MATERIALS 2023; 451:131160. [PMID: 36907061 DOI: 10.1016/j.jhazmat.2023.131160] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/03/2023] [Accepted: 03/04/2023] [Indexed: 06/18/2023]
Abstract
Global eutrophication and climate warming exacerbate production of cyanotoxins such as microcystins (MCs), presenting risks to human and animal health. Africa is a continent suffering from severe environmental crises, including MC intoxication, but with very limited understanding of the occurrence and extent of MCs. By analysing 90 publications from 1989 to 2019, we found that in various water bodies where MCs have been detected so far, the concentrations were 1.4-2803 times higher than the WHO provisional guideline for human lifetime exposure via drinking water (1 µg/L) in 12 of 15 African countries where data were available. MCs were relatively high in the Republic of South Africa (averaged 2803 μg/L) and Southern Africa as a whole (702 μg/L) when compared to other regions. Values were higher in reservoirs (958 μg/L) and lakes (159 μg/L) than in other water types, and much higher in temperate (1381 μg/L) than in arid (161 μg/L) and tropical (4 μg/L) zones. Highly significant positive relationships were found between MCs and planktonic chlorophyll a. Further assessment revealed high ecological risk for 14 of the 56 water bodies, with half used as human drinking water sources. Recognizing the extremely high MCs and exposure risk in Africa, we recommend routine monitoring and risk assessment of MCs be prioritized to ensure safe water use and sustainability in this region.
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Affiliation(s)
- Xu Zhao
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Ying Liu
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Yu-Ming Guo
- Climate, Air Quality Research Unit, School of Public Health and Preventive Medicine, Monash University, Melbourne, 3004, Australia; Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, 3004, Australia
| | - Chi Xu
- School of Life Sciences, Nanjing University, Nanjing, 210023, China
| | - Liang Chen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Geoffrey A Codd
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK; Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK
| | - Jun Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences (UCAS), Beijing 100049, China
| | - Ying Wang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Pu-Ze Wang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Li-Wei Yang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Long Zhou
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Yan Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Shi-Man Xiao
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China
| | - Hai-Jun Wang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China.
| | - Hans W Paerl
- Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC 28557, USA
| | - Erik Jeppesen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China; Department of Ecoscience, Aarhus University, Aarhus, 8000, Denmark; Sino-Danish Centre for Education and Research, Beijing, 100190, China; Limnology Laboratory, Department of Biological Sciences, and Centre for Ecosystem Research and Implementation (EKOSAM), Middle East Technical University, Ankara, 06800, Turkey; Institute of Marine Sciences, Middle East Technical University, Mersin, 33731, Turkey
| | - Ping Xie
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650500, China; Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences (UCAS), Beijing 100049, China.
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Hill D, Lang J, McCord J, Strynar M, Rosal C, Schmid J, Le TT, Chernoff N. Variability of Microcystin-LR Standards Available from Seven Commercial Vendors. Toxins (Basel) 2022; 14:toxins14100705. [PMID: 36287973 PMCID: PMC9611723 DOI: 10.3390/toxins14100705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 12/05/2022] Open
Abstract
Microcystins (MCs) are a large group of heptapeptide cyanobacterial toxins commonly produced in harmful algal blooms (HABs) and associated with adverse health effects in wildlife, livestock, pets, and humans. MC chemical standards are extracted from cyanobacteria biomass rather than produced synthetically and are used in water assessment methods and toxicological studies. MC standards are generally supplied in less than 1 mg quantities, and verification of the mass can only be accomplished by analytical chemistry methods using a certified reference of the specific MC for comparison. Analytical quantification of MCs in environmental samples and toxicology studies using accurate doses of test chemicals administered to experimental animals rely on the availability and accuracy of chemical standards. To check the accuracy and purity of available standards, seven individual microcystin-LR (MCLR) standards were purchased from separate commercial vendors and analyzed to determine the actual mass supplied and identify the presence of potential contaminants. To determine the effect of varying toxin mass in toxicological studies, each MCLR standard was administered to CD-1 mice in doses based on mass purchased, by a single 40 µg/kg intraperitoneal injection. The measured mass purchased varied from the vendor label mass by more than 35% for two of the seven MCLR standards. Contaminants, including trifluoroacetic acid (TFA), were identified in four of the seven samples. Comparative in vivo hepatotoxicity between vendor samples closely reflected the actual amount of MCLR present in each standard and demonstrated the toxicological impact of varying cyanotoxin mass.
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Affiliation(s)
- Donna Hill
- Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA
- Correspondence:
| | - Johnsie Lang
- Arcadis (United States), 4204 Technology Dr, Durham, NC 27704, USA
| | - James McCord
- Center for Environmental Measurement and Modeling, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Mark Strynar
- Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | | | - Judith Schmid
- Center for Public Health and Environmental Assessment, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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Reporting of Freshwater Cyanobacterial Poisoning in Terrestrial Wildlife: A Systematic Map. Animals (Basel) 2022; 12:ani12182423. [PMID: 36139281 PMCID: PMC9494982 DOI: 10.3390/ani12182423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/26/2022] [Accepted: 09/12/2022] [Indexed: 12/24/2022] Open
Abstract
Simple Summary Harmful cyanobacterial blooms (cyanoHABs) have been reported globally, threatening human and animal health. They are encouraged by the warming climate and agricultural pollution creating nutrient-rich, warm environments, ideal for cyanobacterial proliferation. The cyanotoxins produced by these blooms have caused poisonings in many wildlife species; however, these cases are severely underreported, and many are likely missed. The aim of this systematic map was to collate, organise, and characterise all existing reports of cyanotoxin poisonings in terrestrial wildlife. We conducted a search of the published literature using online databases, yielding a total of 45 cases detailing incidents involving terrestrial wildlife. There is no current standard method for the reporting and diagnosis of cyanotoxin intoxication cases, and we provide recommendations on this to include both clinical diagnostic tools and investigative chemistry techniques. Less than half of all cases employed robust methods of detection and diagnosis based on our recommendations. Most cases were investigated after poisonings had already occurred, and only nine reports mentioned any effort to mitigate the effects of harmful cyanobacteria on terrestrial wildlife. This systematic map details terrestrial wildlife cyanotoxin intoxications from a diagnostic perspective, identifying how reporting can be improved, leading to more successful mitigation and investigative efforts in the future. Abstract Global warming and over-enrichment of freshwater systems have led to an increase in harmful cyanobacterial blooms (cyanoHABs), affecting human and animal health. The aim of this systematic map was to detail the current literature surrounding cyanotoxin poisonings in terrestrial wildlife and identify possible improvements to reports of morbidity and mortality from cyanotoxins. A systematic search was conducted using the electronic databases Scopus and Web of Science, yielding 5059 published studies identifying 45 separate case reports of wildlife poisonings from North America, Africa, Europe, and Asia. Currently, no gold standard for the diagnosis of cyanotoxin intoxication exists for wildlife, and we present suggested guidelines here. These involved immunoassays and analytical chemistry techniques to identify the toxin involved, PCR to identify the cyanobacterial species involved, and evidence of ingestion or exposure to cyanotoxins in the animals affected. Of the 45 cases, our recommended methods concurred with 48.9% of cases. Most often, cases were investigated after a mortality event had already occurred, and where mitigation was implemented, only three cases were successful in their efforts. Notably, only one case of invasive cyanobacteria was recorded in this review despite invasive species being known to occur throughout the globe; this could explain the underreporting of invasive cyanobacteria. This systematic map highlights the perceived absence of robust detection, surveillance, and diagnosis of cyanotoxin poisoning in wildlife. It may be true that wildlife is less susceptible to these poisoning events; however, the true rates of poisoning are likely much more than is reported in the literature.
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Woodburn DB, Steyl J, Du Plessis EC, Last RD, Reininghaus B, Mitchell EP. Pathological findings in African buffaloes (Syncerus caffer) in South Africa. J S Afr Vet Assoc 2021; 92:e1-e11. [PMID: 34476957 PMCID: PMC8424707 DOI: 10.4102/jsava.v92i0.2117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 06/04/2021] [Accepted: 06/15/2021] [Indexed: 11/05/2022] Open
Abstract
The African buffalo (Syncerus caffer) is an iconic species of South African megafauna. As the farmed buffalo population expands, the potential impacts on population health and disease transmission warrant investigation. A retrospective study of skin biopsy and necropsy samples from 429 animals was performed to assess the spectrum of conditions seen in buffaloes in South Africa. Determination of the cause of death (or euthanasia) could not be made in 33.1% (136/411) of the necropsy cases submitted due to autolysis or the absence of significant lesions in the samples submitted. Infectious and parasitic diseases accounted for 53.5% (147/275) of adult fatal cases and non-infectious conditions accounted for 34.9% (96/275). Abortions and neonatal deaths made up 11.6% (32/275) of necropsy cases. Rift Valley fever, bovine viral diarrhoea, malignant catarrhal fever, tuberculosis, bacterial pneumonia, anaesthetic deaths, cachexia and hepatotoxic lesions were the most common causes of death. The range of infectious, parasitic and non-infectious diseases to which African buffaloes were susceptible was largely similar to diseases in domestic cattle which supports concerns regarding disease transmission between the two species. The similarity between diseases experienced in both species will assist wildlife veterinarians in the diagnosis and treatment of diseases in captive African buffaloes. The present study likely does not represent accurate disease prevalence data within the source population of buffaloes, and diseases such as anthrax, brucellosis and foot and mouth disease are under-represented in this study. Hepatic ductal plate abnormalities and haemorrhagic septicaemia have not, to our knowledge, been previously reported in African buffaloes.
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Affiliation(s)
- Daniel B Woodburn
- Department of Pathobiology, Zoological Pathology Program, University of Illinois, Illinois.
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Titus AL, Knoll K, Sertich JJW, Yamamura D, Suarez CA, Glasspool IJ, Ginouves JE, Lukacic AK, Roberts EM. Geology and taphonomy of a unique tyrannosaurid bonebed from the upper Campanian Kaiparowits Formation of southern Utah: implications for tyrannosaurid gregariousness. PeerJ 2021; 9:e11013. [PMID: 33976955 PMCID: PMC8061582 DOI: 10.7717/peerj.11013] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 02/05/2021] [Indexed: 11/20/2022] Open
Abstract
Tyrannosaurids are hypothesized to be gregarious, possibly parasocial carnivores engaging in cooperative hunting and extended parental care. A tyrannosaurid (cf. Teratophoneus curriei) bonebed in the late Campanian age Kaiparowits Formation of southern Utah, nicknamed the Rainbows and Unicorns Quarry (RUQ), provides the first opportunity to investigate possible tyrannosaurid gregariousness in a taxon unique to southern Laramidia. Analyses of the site's sedimentology, fauna, flora, stable isotopes, rare earth elements (REE), charcoal content and taphonomy suggest a complex history starting with the deaths and transport of tyrannosaurids into a peri-fluvial, low-energy lacustrine setting. Isotopic and REE analyses of the fossil material yields a relatively homogeneous signature indicating the assemblage was derived from the same source and represents a fauna living in a single ecospace. Subsequent drying of the lake and fluctuating water tables simultaneously overprinted the bones with pedogenic carbonate and structurally weakened them through wet-dry cycling. Abundant charcoal recovered from the primary bone layer indicate a low temperature fire played a role in the site history, possibly triggering an avulsion that exhumed and reburied skeletal material on the margin of a new channel with minimal transport. Possible causes of mortality and concentration of the tyrannosaurids include cyanobacterial toxicosis, fire, and flooding, the latter being the preferred hypothesis. Comparisons of the RUQ site with other North American tyrannosaur bonebeds (Dry Island-Alberta; Daspletosaurus horneri-Montana) suggest all formed through similar processes. Combined with ichnological evidence, these tyrannosaur mass-burial sites could be part of an emerging pattern throughout Laramidia reflecting innate tyrannosaurid behavior such as habitual gregariousness.
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Affiliation(s)
- Alan L Titus
- Paria River District, US Bureau of Land Management, Kanab, UT, USA
| | - Katja Knoll
- Paria River District, US Bureau of Land Management, Kanab, UT, USA
| | - Joseph J W Sertich
- Department of Earth Sciences, Denver Museum of Nature and Science, Denver, CO, USA
| | - Daigo Yamamura
- Department of Geosciences, University of Arkansas at Fayetteville, Fayetteville, AR, USA
| | - Celina A Suarez
- Department of Geosciences, University of Arkansas at Fayetteville, Fayetteville, AR, USA
| | | | | | | | - Eric M Roberts
- Department of Earth and Environmental Sciences, James Cook University of North Queensland, Townsville, QLD, Australia
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van Aarde RJ, Pimm SL, Guldemond R, Huang R, Maré C. The 2020 elephant die-off in Botswana. PeerJ 2021; 9:e10686. [PMID: 33510975 PMCID: PMC7808262 DOI: 10.7717/peerj.10686] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 12/11/2020] [Indexed: 12/02/2022] Open
Abstract
The cause of deaths of 350 elephants in 2020 in a relatively small unprotected area of northern Botswana is unknown, and may never be known. Media speculations about it ignore ecological realities. Worse, they make conjectures that can be detrimental to wildlife and sometimes discredit conservation incentives. A broader understanding of the ecological and conservation issues speaks to elephant management across the Kavango–Zambezi Transfrontier Conservation Area that extends across Botswana, Namibia, Angola, Zambia, and Zimbabwe. Our communication addresses these. Malicious poisoning and poaching are unlikely to have played a role. Other species were unaffected, and elephant carcases had their tusks intact. Restriction of freshwater supplies that force elephants to use pans as a water source possibly polluted by blue-green algae blooms is a possible cause, but as yet not supported by evidence. No other species were involved. A contagious disease is the more probable one. Fences and a deep channel of water confine these elephants’ dispersal. These factors explain the elephants’ relatively high population growth rate despite a spell of increased poaching during 2014–2018. While the deaths represent only ~2% of the area’s elephants, the additive effects of poaching and stress induced by people protecting their crops cause alarm. Confinement and relatively high densities probably explain why the die-off occurred only here. It suggests a re-alignment or removal of fences that restrict elephant movements and limits year-round access to freshwater.
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Affiliation(s)
- Rudi J van Aarde
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, Gauteng, South Africa
| | - Stuart L Pimm
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, Gauteng, South Africa.,Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Robert Guldemond
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, Gauteng, South Africa
| | - Ryan Huang
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Celesté Maré
- Conservation Ecology Research Unit, Department of Zoology and Entomology, University of Pretoria, Hatfield, Gauteng, South Africa
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Fritsch CJ, Downs CT. Evaluation of low‐cost consumer‐grade
UAVs
for conducting comprehensive high‐frequency population censuses of hippopotamus populations. CONSERVATION SCIENCE AND PRACTICE 2020. [DOI: 10.1111/csp2.281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Camille J. Fritsch
- Centre for Functional Biodiversity School of Life Sciences, University of KwaZulu‐Natal Scottsville South Africa
| | - Colleen T. Downs
- Centre for Functional Biodiversity School of Life Sciences, University of KwaZulu‐Natal Scottsville South Africa
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Utete B. A review of some aspects of the ecology, population trends, threats and conservation strategies for the common hippopotamus, Hippopotamus amphibius L, in Zimbabwe. AFRICAN ZOOLOGY 2020. [DOI: 10.1080/15627020.2020.1779613] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Beaven Utete
- Department of Wildlife Ecology and Conservation, Chinhoyi University of Technology, Chinhoyi, Zimbabwe
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Chu C, Steyl J, Du Plessis EC, Reininghaus B, Mitchell EP. A review of pathological findings in impalas (Aepyceros melampus) in South Africa. J S Afr Vet Assoc 2020; 91:e1-e10. [PMID: 32787424 PMCID: PMC7479362 DOI: 10.4102/jsava.v91i0.1965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 11/01/2022] Open
Abstract
Impalas (Aepyceros melampus) are common African antelope. A retrospective study was conducted of 251 impala cases from game farms, national parks and zoos submitted by veterinarians and pathologists in South Africa (2003-2016). Histopathology slides as well as records of macroscopic lesions and additional diagnostic tests performed were examined. Non-infectious conditions, such as acute pulmonary congestion and oedema, cachexia, traumatic injury and anaesthetic-related mortality were the most common causes of morbidity and mortality. Bacterial sepsis was the most common infectious disease, whilst skeletal muscle and myocardial sarcocystosis and verminous cholangitis and pneumonia were the most common parasitic diseases. Although the retrospective nature of this study limits the significance of the relative prevalence of lesions in the three locations, management decisions and diagnostic plans may be informed by the results. Impala from game farms had significantly more cachexia cases than those from other locations. Impala from zoos had significantly more lymphoid depletion than those from other locations. These findings suggest that nutrition and pasture management, enclosure design, management of intra- and interspecies aggression and improved anaesthetic protocols could improve animal welfare and survival of impala on game farms and in zoos. This report presents a detailed survey of diseases and conditions found in impala that provides baseline data for veterinary pathologists.
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Affiliation(s)
- Caroline Chu
- Zoological Pathology Program, University of Illinois, Chicago, United States; and, Charles River Laboratories, Senneville.
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Azeem S, Bengis R, Van Aarde R, Bastos AD. Mass Die-Off of African Elephants in Botswana: Pathogen, Poison or a Perfect Storm? AFRICAN JOURNAL OF WILDLIFE RESEARCH 2020. [DOI: 10.3957/056.050.0149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Shahan Azeem
- Virology Section, Institute of Microbiology, University of Veterinary and Animal Sciences, Lahore. Pakistan
| | - Roy Bengis
- Retired Chief State Veterinarian, Kruger National Park, South Africa
| | - Rudi Van Aarde
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Armanda D.S. Bastos
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
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The Comparative Toxicity of 10 Microcystin Congeners Administered Orally to Mice: Clinical Effects and Organ Toxicity. Toxins (Basel) 2020; 12:toxins12060403. [PMID: 32570788 PMCID: PMC7354475 DOI: 10.3390/toxins12060403] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 12/16/2022] Open
Abstract
Microcystins (MCs) are common cyanobacterial toxins that occur in freshwaters worldwide. Only two of the >200 MC variants have been tested for potential toxicity after oral exposure. This paper reports on the toxicity of 10 different MC congeners identified in algal blooms, microcystin-LR (MCLR), MCLA, MCLF, MCLW, MCLY, MCRR, [Asp3]MCRR, [Asp3,Dhb7]MCRR, MCWR, and MCYR after single administrations to BALB/c mice. In a preliminary MCLR dose–response study of 3 to 9 mg/kg doses, ≥5 mg/kg induced clinical changes, increased serum levels of ALT, AST, and GLDH, liver congestion, increased liver/body weight ratios, and reduced serum glucose and total protein. Based on the extent of these effects, the 10 congeners were administered as single 7 mg/kg oral doses and toxicity evaluated. The greatest toxicity was observed with MCLA and MCLR including a high percentage of moribundity. In addition to eliciting effects similar to those listed above for MCLR, MCLA also induced serum alterations indicative of jaundice. MCLY, and MCYR induced changes like those noted with MCLR, but to lesser extents. MCLW and MCLF exhibited some serum and morphological changes associated with hepatic toxicity, while there were few indications of toxicity after exposures to MCRR, [Asp3]MCRR, [Asp3,Dhb7]MCRR, or MCWR. These data illustrate a wide spectrum of hepatic effects and different potencies of these MC congeners.
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12
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McCord J, Lang JR, Hill D, Strynar M, Chernoff N. pH dependent octanol-water partitioning coefficients of microcystin congeners. JOURNAL OF WATER AND HEALTH 2018; 16:340-345. [PMID: 29952323 PMCID: PMC6084446 DOI: 10.2166/wh.2018.257] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Hazardous algal blooms can generate toxic compounds with significant health impacts for exposed communities. The ubiquitous class of algal toxins known as microcystins exhibits significant heterogeneity in its peptide structure, which has been minimally studied, given the significant impact this has on hydrophobicity, acid/base character and related environmental fate and health effects. Octanol-water partition coefficients for the microcystin congeners MCLR, MCRR, MCLY, MCLF, and MCLA were calculated over an environmentally and physiologically relevant pH range. Microcystin-LR log(Kow) partition coefficient values were found to be consistent with previously established literature values, 1.67 to -1.41 between pH 1 and 8. Microcystin RR was found to be pH insensitive with a log(Kow) of -0.7. The remaining congeners exhibit similar pH dependence as MCLR, with systematic increases in hydrophobicity driven by the introduction of more hydrophobic residues to their variable amino acid region. The variation in pH dependent hydrophobicity suggests increased propensity for bioaccumulation and alternate environmental fates for differing microcystin forms, requiring further investigation.
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Affiliation(s)
- James McCord
- Oak Ridge Institute for Science and Education, Oak Ridge, TN 37831, USA E-mail:
| | - Johnsie R Lang
- Oak Ridge Institute for Science and Education, Oak Ridge, TN 37831, USA E-mail:
| | - Donna Hill
- National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Mark Strynar
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
| | - Neil Chernoff
- National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA
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Bengis R, Govender D, Lane E, Myburgh J, Oberholster P, Buss P, Prozesky L, Keet D. Eco-epidemiological and pathological features of wildlife mortality events related to cyanobacterial bio-intoxication in the Kruger National Park, South Africa. J S Afr Vet Assoc 2016; 87:e1-e9. [PMID: 28155293 PMCID: PMC6138192 DOI: 10.4102/jsava.v87i1.1391] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 06/24/2016] [Accepted: 09/23/2016] [Indexed: 11/01/2022] Open
Abstract
Over the past decade, several clustered, multispecies, wildlife mortality events occurred in the vicinity of two man-made earthen dams in the southern and south central regions of the Kruger National Park, South Africa. On field investigation, heavy cyanobacterial blooms were visible in these impoundments and analysis of water samples showed the dominance of Microcystis spp. (probably Microcystis aeruginosa). Macroscopic lesions seen at necropsy and histopathological lesions were compatible with a diagnosis of cyanobacterial intoxication. Laboratory toxicity tests and assays also confirmed the presence of significant levels of microcystins in water from the two dams. These outbreaks occurred during the dry autumn and early winter seasons when water levels in these dams were dropping, and a common feature was that all the affected dams were supporting a large number of hippopotamuses (Hippopotamus amphibius). It is hypothesised that hippopotamus' urine and faeces, together with agitation of the sediments, significantly contributed to internal loading of phosphates and nitrogen - leading to eutrophication of the water in these impoundments and subsequent cyanobacterial blooms. A major cause for concern was that a number of white rhinoceros (Ceratotherium simum) were amongst the victims of these bio-intoxication events. This publication discusses the eco-epidemiology and pathology of these clustered mortalities, as well as the management options considered and eventually used to address the problem.
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