First report of homoanatoxin-a and associated dog neurotoxicosis in New Zealand.
In November 2005, at least five dogs died rapidly after contact with water from the Hutt River (lower North Island, New Zealand). Necropsy performed 24h later on one of the dogs (a 20-month-old Labrador) revealed few findings of interest, except for copious amounts of froth in the respiratory tract down to the bifurcation of the trachea and large quantities of algal material in the dog's stomach. Low and relatively stable flows in the Hutt River during spring had resulted in the proliferation of benthic cyanobacteria that formed large black/brown mats along the river edge. Samples from the Labrador's stomach contents and cyanobacterial mats were analysed microscopically and screened using chemical and biochemical assays for cyanotoxins: anatoxin-a, homoanatoxin-a, cylindrospermopsins, saxitoxins and microcystins. Liquid chromatography-mass spectrometry (LC-MS) confirmed the presence of the neurotoxic cyanotoxins anatoxin-a and homoanatoxin-a and their degradation products, dihydro-anatoxin-a and dihydro-homoanatoxin-a. This is the first report of homoanatoxin-a and associated degradation product in New Zealand. Based on morphology, the causative species was identified as Phormidium sp. Subsequent phylogenetic analysis of 16S rRNA gene sequences demonstrated that the causative organism was most similar to Phormidium autumnale. Further investigations led to the detection of homoanatoxin-a and anatoxin-a in cyanobacterial mats from four other rivers in the Wellington region (lower North Island, New Zealand). Access restrictions were placed on over 60% of river catchments in the western Wellington region, severely affecting recreational users.
Wood
Susanna A
SA
Cawthron Institute, Private Bag 2, Nelson 7001, New Zealand. susie.wood@cawthron.org.nz
Selwood
Andrew I
AI
Rueckert
Andreas
A
Holland
Patrick T
PT
Milne
Juliet R
JR
Smith
Kirsty F
KF
Smits
Bronwyn
B
Watts
Laura F
LF
Cary
Craig S
CS
D000818:Animals; D001427:Bacterial Toxins / Q000506:poisoning*; D019086:Bridged Bicyclo Compounds, Heterocyclic; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000737:chemistry / Q000648:ultrastructure; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000187:drug effects; D004283:Dog Diseases / Q000139:chemically induced*; D004285:Dogs; D005766:Gastrointestinal Contents / Q000737:chemistry; D008387:Marine Toxins / Q000506:poisoning*; D052998:Microcystins / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity; D020258:Neurotoxicity Syndromes / Q000473:pathology* / Q000662:veterinary*; D009520:New Zealand; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012530:Saxitoxin / Q000737:chemistry / Q000302:isolation & purification / Q000633:toxicity; D016707:Tissue Fixation; D014121:Toxoids / Q000737:chemistry / Q000302:isolation & purification
D001427:Bacterial Toxins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D008387:Marine Toxins; D052998:Microcystins; D012336:RNA, Ribosomal, 16S; D014121:Toxoids; C524097:homoanatoxin-a; D012530:Saxitoxin