Desert bighorn sheep mortality due to presumptive type C botulism in California

Pamela K. Swift, John D. Wehausen, Holly B Ernest, Randall S. Singer, Andrew M. Pauli, Hailu Kinde, Tonie E. Rocke, Vernon C. Bleich

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


During a routine telemetry flight of the Mojave Desert (California, USA) in August 1995, mortality signals were detected from two of 12 radio-collared female desert bighorn sheep (Ovis canadensis) in the vicinity of Old Dad Peak in San Bernardino County (California). A series of field investigations determined that at least 45 bighorn sheep had died near two artificial water catchments (guzzlers), including 13 bighorn sheep which had presumably drowned in a guzzler tank. Samples from water contaminated by decomposing bighorn sheep carcasses and hemolyzed blood from a fresh bighorn sheep carcass were tested for the presence of pesticides, heavy metals, strychnine, blue-green algae, Clostridium botulinum toxin, ethylene glycol, nitrates, nitrites, sodium, and salts. Mouse bioassay and enzyme-linked immunosorbent assay detected type C botulinum toxin in the hemolyzed blood and in fly larvae and pupae. This, coupled with negative results from other analyses, led us to conclude that type C botulinum poisoning was most likely responsible for the mortality of bighorn sheep outside the guzzler tank.

Original languageEnglish (US)
Pages (from-to)184-189
Number of pages6
JournalJournal of Wildlife Diseases
Issue number1
StatePublished - Jan 2000


  • Bighorn sheep
  • Botulinum toxin
  • Clostridium botulinum type C
  • Mortality event
  • Ovis canadensis

ASJC Scopus subject areas

  • veterinary(all)


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