Cattle mortality attributed to the toxic cyanobacterium Cylindrospermopsis raciborskii in an outback region of North Queensland

Abstract

Three cows and ten calves were found dead near a farm dam on a cattle property at McKinlay in northwest Queensland, Australia. At that time, the dam contained an algal bloom which was identified as a monoculture of the cyanobacterium C. raciborskii. Histological examination of the liver of a calf carcass showed signs consistent with poisoning caused by hepatotoxin. The hepatotoxic alkaloid cylindrospermopsin was detected in material harvested from the dam (4.1×10-15 g cell-1) and in a pure culture of an isolate from the bloom (4.4×10-15 g cell-1). An extract of this material was lethal to mice after 24 h at an intraperitoneal concentration of 153 mg kg-1. This appears to be the first report of animal poisonings attributed to the cyanobacterium C. raciborskii.