A comparative microbiological study of clinically healthy eyes and those affected by ophthalmia in cattle and the association of noctuid eye-frequenting moths.

The eyes of clinically healthy Simmentaler cattle and those affected by ophthalmia were sampled once a month over a continuous period of 12 months for bacterial, mycoplasmal and ureaplasmal infections. In total 478 eyes, representing from a clinical viewpoint 414 healthy and 64 affected eyes, were swabbed. Bacteria were isolated from 201 (48.6%) healthy eyes and 56 (87.5%) affected eyes. No bacteria were isolated from the remaining eyes. Eleven genera of bacteria were isolated from healthy eyes and 8 genera from affected eyes. The majority of isolates were classified in the genera Moraxella, Neisseria and Staphylococcus. Mycoplasmas were isolated from 247 (50.7%) healthy eyes and 27 (42.2%) affected eyes. No mycoplasmas were isolated from the remaining eyes. Ureaplasmas were not isolated from any animal. Eye-frequenting moths were collected on 3 occasions during the investigation and bacterial and mycoplasmal isolation techniques were performed on a total of 21 moths. Twelve different genera of bacteria, mostly Nocardia, Corynebacterium, Staphylococcus, Moraxella, and mycoplasmas were isolated from various eye-frequenting moths. Scanning electron microscopical studies of the proboscis of the moths showed it to contain various sensillae and short triangular denticles that could possibly cause damage to the mucous membranes of the eyes and predispose to ophthalmia in cattle.