Peer-reviewed veterinary case report
Listeria monocytogenes associated kerato-conjunctivitis in four horses in Norway.
- Journal:
- Acta veterinaria Scandinavica
- Year:
- 2015
- Authors:
- Revold, Tobias et al.
- Affiliation:
- Department of Companion Animal Clinical Sciences
- Species:
- horse
Plain-English summary
In Norway, four horses were diagnosed with kerato-conjunctivitis, which is an eye infection affecting the cornea and conjunctiva. This infection was linked to a bacteria called Listeria monocytogenes, which is known to cause various diseases in both people and animals, though eye infections are rare. All four horses showed signs of recurrent eye problems, and tests confirmed the presence of L. monocytogenes in their eye samples. The horses did not respond well to treatment, suggesting that if this bacteria is found in similar cases, veterinarians should be careful about how long and how intensely they treat the infection. Overall, the treatment was not effective in these cases.
Abstract
Listeria monocytogenes has been reported to cause various infectious diseases in both humans and animals. More rarely, ocular infections have been reported. To our knowledge, only two cases of Listeria keratitis have been described in horses. We report kerato-conjunctivitis in four Norwegian horses associated with L. monocytogenes. Clinically, all cases were presented with recurrent unilateral kerato-conjunctivitis. L. monocytogenes bacteria were isolated from swab samples from all cases, and cytology carried out in 3 cases was indicative of L. monocytogenes infection. The present report describes the first known cases in which L. monocytogenes has been isolated from keratitic lesions in horses in Norway. A potential risk factor may be feeding of silage or haylage, but other sources of infection cannot be ruled out. The phenotypic features including antimicrobial susceptibility and serotype of the isolates are described. Laboratory detection of L. monocytogenes demands extra caution since only low numbers of bacteria were detected in the eye-swabs, probably due to the low volume of sample material and the intracellular niche of the bacterium. A general poor response to treatment in all these cases indicates that clinicians should pay extra attention to intensity and duration of treatment if L. monocytogenes is identified in connection with equine kerato-conjunctivitis.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/26552393/