title: Grazing livestock are exposed to terrestrial cyanobacteria.
abstract: While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.
authors.forename: Bruce C
authors.initials: BC
authors.lastname: McGorum
authors.forename: R Scott
authors.initials: RS
authors.lastname: Pirie
authors.forename: Laura
authors.initials: L
authors.lastname: Glendinning
authors.forename: Gerry
authors.initials: G
authors.lastname: McLachlan
authors.forename: James S
authors.initials: JS
authors.lastname: Metcalf
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Banack
authors.forename: Paul A
authors.initials: PA
authors.lastname: Cox
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Codd
mesh_terms: D000599:Amino Acids, Diamino / Q000032:analysis; D000822:Animal Husbandry; D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D000458:Cyanobacteria / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D000087522:Cyanobacteria Toxins; D004269:DNA, Bacterial / Q000235:genetics; D004739:England; D005602:France; D005766:Gastrointestinal Contents / Q000382:microbiology*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D006734:Horse Diseases / Q000382:microbiology* / Q000473:pathology; D006736:Horses; D008107:Liver Diseases / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D058751:Livestock; D016472:Motor Neuron Disease / Q000382:microbiology / Q000473:pathology / Q000662:veterinary; D009498:Neurotoxins / Q000032:analysis; D010944:Plants / Q000382:microbiology; D011156:Population Density; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012606:Scotland
chemical_list: D000599:Amino Acids, Diamino; D000087522:Cyanobacteria Toxins; D004269:DNA, Bacterial; D009498:Neurotoxins; D012336:RNA, Ribosomal, 16S; C001824:beta-N-methylamino-L-alanine
references.citation: Science. 1961 Jul 21;134(3473):188-90
references.pmid: 13740946
references.citation: Int J Environ Res Public Health. 2011 Sep;8(9):3728-46
references.pmid: 22016712
references.citation: Med Hypotheses. 2013 Jan;80(1):103
references.pmid: 23146671
references.citation: Appl Environ Microbiol. 2006 Jul;72(7):5069-72
references.pmid: 16820507
references.citation: Elife. 2013;2:e01102
references.pmid: 24137540
references.citation: J Neurochem. 1966 Dec;13(12):1461-7
references.pmid: 5962024
references.citation: Equine Vet J. 1991 Sep;23(5):365-9
references.pmid: 1959528
references.citation: J Bacteriol. 1977 Apr;130(1):1-3
references.pmid: 404280
references.citation: Ann Microbiol (Paris). 1983 Jul-Aug;134B(1):61-72
references.pmid: 6416128
references.citation: Proc Natl Acad Sci U S A. 2005 Aug 2;102(31):11070-5
references.pmid: 16033867
references.citation: PLoS One. 2012;7(11):e49043
references.pmid: 23145061
references.citation: Toxicon. 2005 Jun 1;45(7):919-28
references.pmid: 15904687
references.citation: PLoS One. 2013;8(12):e83406
references.pmid: 24349504
references.citation: Amyotroph Lateral Scler. 2009;10 Suppl 2:7-20
references.pmid: 19929726
references.citation: Bioinformatics. 2011 Aug 15;27(16):2194-200
references.pmid: 21700674
references.citation: Genome Biol Evol. 2014 May;6(5):1031-45
references.pmid: 24709563
references.citation: Res Vet Sci. 1992 Jul;53(1):106-9
references.pmid: 1410805
references.citation: Folia Microbiol (Praha). 2002;47(1):61-7
references.pmid: 11980272
references.citation: Proc Natl Acad Sci U S A. 2003 Nov 11;100(23):13380-3
references.pmid: 14612559
references.citation: FEMS Microbiol Lett. 2012 Jan;326(1):62-8
references.pmid: 22092776
references.citation: ISME J. 2012 Jan;6(1):94-103
references.pmid: 21716311
references.citation: Mol Nutr Food Res. 2007 Jan;51(1):7-60
references.pmid: 17195276
references.citation: Science. 1987 Jul 31;237(4814):517-22
references.pmid: 3603037
references.citation: Appl Environ Microbiol. 2013 Sep;79(17):5112-20
references.pmid: 23793624
references.citation: Chem Biol Interact. 2014 May 25;215:54-61
references.pmid: 24667652
references.citation: Science. 2005 Jun 10;308(5728):1635-8
references.pmid: 15831718
references.citation: Proc Natl Acad Sci U S A. 2005 Apr 5;102(14):5074-8
references.pmid: 15809446
references.citation: J Biol Chem. 1963 Jul;238:2460-3
references.pmid: 13936836
references.citation: Toxicon. 2010 Feb-Mar;55(2-3):547-57
references.pmid: 19825383
references.citation: Science. 2005 Mar 25;307(5717):1915-20
references.pmid: 15790844
references.citation: Nucleic Acids Res. 2007;35(21):7188-96
references.pmid: 17947321
references.citation: J Histochem Cytochem. 2009 Sep;57(9):849-60
references.pmid: 19471015
references.citation: Equine Vet J. 2006 Jan;38(1):47-51
references.pmid: 16411586
references.citation: Int J Syst Bacteriol. 1998 Apr;48 Pt 2:403-10
references.pmid: 9731278
references.citation: FEMS Microbiol Ecol. 2003 Aug 1;45(3):263-72
references.pmid: 19719595
references.citation: Appl Environ Microbiol. 2009 Dec;75(23):7537-41
references.pmid: 19801464
references.citation: Front Pharmacol. 2010 Oct 25;1:122
references.pmid: 21833167
references.citation: Toxicology. 2011 Dec 18;290(2-3):218-29
references.pmid: 22000993
references.citation: Equine Vet J. 2010 Sep;42(6):477-81
references.pmid: 20716184
references.citation: Appl Environ Microbiol. 1989 Jan;55(1):261-3
references.pmid: 16347828
references.citation: Equine Vet J. 2004 Mar;36(2):130-4
references.pmid: 15038435
references.citation: Acta Neurol Scand. 2009 Oct;120(4):216-25
references.pmid: 19254284