Peer-reviewed veterinary case report
First case report of Corynebacterium pseudotuberculosis biovar equi in semiarid region of Brazil.
- Journal:
- Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology]
- Year:
- 2025
- Authors:
- de Souza Lima, Ewerton et al.
- Affiliation:
- Veterinary Science Department · Brazil
- Species:
- horse
Plain-English summary
A Quarter Horse in Northeastern Brazil was diagnosed with a bacterial infection caused by Corynebacterium pseudotuberculosis, specifically a strain known as biovar equi. This bacterium can lead to serious health issues like ulcerative lymphangitis, which is an infection that causes painful swelling and sores in the limbs. Testing methods, including genetic analysis, confirmed the specific strain and showed it was closely related to a strain found in Chile. This case is significant because it is the first time this particular strain has been reported in Brazil, indicating a new risk for horses in the area. The findings suggest that farmers should be aware of this new threat and consider updating their health and movement policies for horses.
Abstract
Corynebacterium pseudotuberculosis is a bacterium that causes significant economic damage to farmers, mainly in the semiarid region of Northeastern Brazil. In this context, only biovar ovis has been reported, and it is widespread in small ruminants. However, this report describes the first equine case in Brazil attributable to a biovar equi. Clinically, it is the causative agent of ulcerative lymphangitis, mastitis, necrotic and ulcerative dermatitis. A Quarter Horse from the semiarid Northeast presented ulcerative lymphangitis. Culture, nitrate reduction test, MALDI-TOF, and whole-genome sequencing identified the Cp_Eq_BR01 strain as biovar equi. The 2.37 Mb genome shared > 98% nucleotide identity with other equi strains and clustered most closely with the Chilean isolate E19. Although no unique determinants of virulence or resistance were found, the observed genomic clonality suggests potential for rapid transboundary spread. This first Brazilian detection broadens the recognized host range, alerts the farmer's national equine to a new threat, and highlights the need for routine nitrate testing, and updated movement control policies for equines.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/40593302/