Fatal canine neurotoxicosis attributed to blue-green algae (cyanobacteria)
Gunn, G.J.; Rafferty, A.G.; Rafferty, G.C.; Cockburn, N.; Edwards, C.; Beattie, K.A.; Codd, G.A.
Veterinary Record 130(14): 301-302
1992
ISSN/ISBN: 0042-4900 PMID: 1595148 Document Number: 390407
Six cases of suspected cyanobacterial toxicoses which occurred at Loch Insh, Scotland in 1990 and 1991 are reported. The dogs (2 Scottish Terriers, 3 Springer Spaniels and a Collie) had all either swum in the loch or walked along the shore in July or August when extensive dark brown cyanobacterial accumulation consisting almost entirely of benthic (bottom dwelling) Oscillatoria species was present along the water's edge. Pigmentation of these species included blue (phycocyanin), green (chlorophyll-a) and red (phycoerythrin) pigments. The dogs showed a range of severe nervous symptoms including convulsions, rigors, limb twitching as well as cyanosis, hypersalivation and bradycardia in some cases; 4 dogs died rapidly, one only 15 minutes after swimming in the loch, and 2 survived after treatments with emetics and intravenous fluids. PM examination of two dogs revealed patchy lung congestion, excess pleural fluid and ecchymotic haemorrhgages of the pancreas and surrounding tissue. Histopathology demonstrated only non-specific changes consistent with terminal anoxia or hypoxaemia. Oscillatoria species were present in stomach contents of 3 of the dogs. Anatoxin-a, the postsynaptic neuromuscular blocking agent, was identified in the bloom material and the stomach contents of one dog. These poisonings are the first ascribed to neurotoxic benthic cyanobacteria in freshwaters.