Crotalariosis equorum (“jaagsiekte”) in horses in southern Mozambique, a rare form of pyrrolizidine alkaloid poisoning.

The study investigates an outbreak in southern Mozambique where horses died after showing severe respiratory distress, attributing the cause to pyrrolizidine alkaloid poisoning from the ingestion of certain Crotalaria species.

Objective of the Research

• The primary aim of the study was to understand the factors behind the death of twenty-eight horses in southern Mozambique who exhibited severe respiratory distress.

Methodology

• The study started by performing an autopsy on the deceased horses. They observed that the lungs of these horses were overinflated, fibrotic, portrayed prominent rib impressions, and were emphysematous (air-filled).
• Then, they carried out microscopic examinations that displayed significant proliferation of nonciliated epithelial (Clara) cells in terminal bronchioles and pulmonary fibrosis indicating chronic pneumotoxicity (lung damage due to toxins).
• Hyperplasia (increase in tissue or organs due to increased rate of cell division), desquamation (shedding of the outermost membrane or layer of a tissue), and apical bulging of Clara cells into the bronchiolar lumen were revealed through Transmission electron microscopy.

Findings of the Study

• The study successfully linked the outbreak to ingestion of Crotalaria dura J.M. Wood & M.S. Evans subsp. mozambica Polhill and Crotalaria monteiroi Taub. ex Baker f. var. monteiroi, concluding this ingestion as the cause of the outbreak.
• Using semi-quantitative gas chromatography-mass spectrometry, researchers were able to detect the presence of pyrrolizidine alkaloids in these two Crotalaria species, a group of naturally occurring toxins found in plants.

Significance of the Research

• The research showcased a rare form of pyrrolizidine alkaloid poisoning, termed crotalariosis equorum or “jaagsiekte”.
• It highlighted the severity of pyrrolizidine alkaloid poisoning, which can cause severe respiratory distress in horses and possibly lead to their death.
• The findings provide valuable insights for veterinarians and horse owners in regions where these Crotalaria species are found, guiding them to avoid these toxic plants in horse feeds.