The bacterium Helicobacter pylori, a known disease-causing organism in human medicine, does not appear to be important in horses.

In humans, intensive research efforts have revealed that H. pylori can induce chronic gastritis, ulcers, adenocarcinomas, and lymphoma. Despite the fact that the glandular portion of the horse’s stomach is frequently affected by erosion and ulceration, the cause(s) of the lesions remain unknown.

To determine whether bacteria, including Helicobacter, are involved in the development of lesions in the equine glandular stomach, Lars Mølbak, a nutritionist from the Department of Large Animal Sciences at the University of Copenhagen in Denmark, and colleagues, performed the urease activity test for Helicobacter and analyzed the bacterial content of stomach samples collected from 63 horses.

Gross lesions were noted in 36 of the 63 (57.1%) of the equine stomachs examined. Such lesions included hyperplastic rugae (enlarged stomach folds, n=13), polyploidy masses (n=2), and focal hyperemic, erosive, or ulcerative lesions (n=21).

Not one of the 36 horses with gross lesions had any evidence of Helicobacter based on the two separate tests performed. In fact, remarkably few bacteria were noted in general. Bacteria that were identified included Lactobacillus salivarius, Sarcina ventriculi, and Escherichia-like bacterium clones such as E. fergusonii.

"Gastric Helicobacter species would not be verified in lesions of the glandular stomach of the horse," wrote Mølbak and colleagues. "Since E. fergusonii has been describ