A review on mycotoxins and mycotoxicoses in ruminants and Equidae in South America.

Overview

• This research article reviews the types of mycotoxins and related diseases (mycotoxicoses) affecting ruminants and equids (horses and related species) in South America.
• It highlights the major fungi and toxins involved, their regional distribution, and the specific plants or grains they infect, causing health issues in livestock.

Mycotoxicoses in South American Livestock

• Leukoencephalomalacia in Horses:
  • Caused by molds contaminating grains or grain byproducts.
  • Reported frequently in South America.
• Aflatoxicosis in Cattle:
  • Less frequently reported compared to leukoencephalomalacia.
  • Caused by aflatoxins produced by certain molds.

Major Groups of Mycotoxins with Regional Distribution

• Ergotism:
  • Important mycotoxicosis in South America.
  • Caused by fungi infecting grains—specifically Claviceps purpurea.
  • Also caused by Epichloë coenophiala infecting the grass Schedonorus arundinaceus.

Mycotoxicoses by Indole-Diterpene-Producing Fungi

• Produced by fungi from the Clavicipitaceae family.
• Includes poisoning caused by:
  • Claviceps paspali infecting Paspalum grass species.
  • Claviceps cynodontes infecting Cynodon dactylon (Bermuda grass).
  • Periglandula, a seed-transmitted symbiotic fungus associated with the tremorgenic plant Ipomoea asarifolia.
• Ipomoea asarifolia poisoning is particularly significant in northeastern and northern Brazil.

Mycotoxicoses Caused by Swainsonine-Containing Plants

• Swainsonine is a toxin found in various plants and produced by symbiotic fungi:
  • Ipomoea carnea var. fistulosa contains swainsonine produced by an epibiotic fungus (order Chaetothyriales) growing on the leaf surface.
  • Astragalus species in Argentinian Patagonia are associated with symbiotic endobiotic fungi (Alternaria section Undifilum spp.) producing swainsonine, causing poisoning.

Other Important Mycotoxicoses

• Baccharis Poisoning:
  • Caused mainly by Baccharis coridifolia, a toxic South American plant.
  • Contains macrocyclic trichothecenes, likely produced by an unidentified endophytic fungus.
• Pithomycotoxicosis:
  • Caused by Pithomyces chartarum.
  • Historically significant for cattle grazing on improved pastures (legumes and grasses) in the region.
• Rare Poisonings:
  • Slaframine poisoning.
  • Diplodiosis.
  • Poisoning from barley contaminated with Aspergillus clavatus.
  • These have been occasional diagnoses in Brazil, Uruguay, and Argentina.

Summary

• The occurrence of mycotoxicoses in South American ruminants and equids is largely influenced by the region’s climate, vegetation, and agricultural practices.
• Mycotoxin-producing fungi infect a variety of plants including grains, forage grasses, and poisonous plants, leading to significant livestock health issues.
• Understanding the diversity of fungi and plants involved is essential for diagnosing, managing, and preventing mycotoxicoses in these animals.