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Nine lactating dairy cows were evaluated because of eye lesions. Examination revealed mild to severe ulceration of the lower and/or upper eyelids, mild to severe swelling surrounding affected eyes, and profuse lacrimation. Lesions typically affected 1 eye, and involved the eyelid skin and conjunctiva. Oxytetracycline treatment led to cure within 2 wk.
Blépharite ulcérative et conjonctivite chez des vaches laitières adultes et association avec Moraxella bovoculi. Neuf vaches laitières en lactation ont été évaluées en raison de lésions oculaires. L’examen a révélé une ulcération de légère à grave des paupières inférieures et/ou supérieures, de l’enflure de légère à grave autour des yeux affectés et un larmoiement abondant. Les lésions affectaient habituellement un œil et touchaient la peau de la paupière et la conjonctive. Un traitement à l’oxytétracycline a produit une guérison après 2 semaines.
(Traduit par Isabelle Vallières)
Nine adult Holstein lactating dairy cows were presented for examination during a routine herd check conducted by the attending veterinarian from the Veterinary Teaching and Research Center in Tulare, California. The herd was located in the San Joaquin Valley and had 3000 milking cows. Cows were examined from May to August of 2006 and the principal complaint was ocular lesions.
The first cow examined (#2442) was 2.1 y old and 155 d in milk. On physical examination, abnormalities were localized in both eyes and eyelids. The right eye had severe eyelid swelling, along with profuse lacrimation; the left eye exhibited mild eyelid swelling and lacrimation. On the right lower eyelid there was a single large, elliptical ulcerative lesion approximately 25-mm long, 10-mm wide, and 2-mm deep involving both the eyelid skin and conjunctiva. This lesion extended from the lateral canthus towards the medial canthus. The left eye had a single ulcerated lesion in the middle portion of the lower eyelid. The lesion appeared as a fissure in the lower eyelid, and extended from the palpebral skin to the palpebral conjunctiva. The bulbar conjunctiva was unaffected and did not exhibit signs of inflammation. The sclera appeared normal and the corneas were clear.
Examination of the 8 other cows revealed ulcerative lesions similar to the lesions reported for cow #2442, with varying degrees of severity of palpebral and conjunctival lesions that were confined to only 1 eye of each cow. One cow (#2424) also exhibited corneal ulceration and edema, blepharospasm, photophobia, and lacrimation, signs that were consistent with a clinical diagnosis of infectious bovine keratoconjunctivitis (IBK). Overall, palpebral/conjuctival lesions were equally distributed between left and right eyes of the 9 cows that were examined; lower eyelids were more affected than upper eyelids (8/10 affected eyes versus 2/10; P = 0.023; Fisher’s exact test) (Table 1). In 3 cows (#2442, 2424, and 8108), punch biopsies of the ulcerative lesions were collected so as to include affected as well as apparently healthy tissue; from 2 biopsied cows, a bacterial culture swab was collected from the affected conjunctiva. These samples were submitted to the California Animal Health & Food Safety Laboratory System, Tulare, California, USA for histologic evaluation and aerobic bacterial culture and sensitivity testing.
The biopsy from the right eye of cow #2442 revealed an erosive epithelium with a moderate proliferative neutrophilic dermatitis, pronounced pseudoepitheliomatous hyperplasia of the epidermis and numerous infiltrating neutrophils (blepharitis). A bacterial origin of this lesion was suspected. In cow #2424, a subacute ulcerative conjunctivitis with erosive suppurative inflammation and bacterial colonization of the surface was observed. The biopsy from cow #8108 revealed a subacute ulcerative and suppurative dermatitis (blepharitis) and conjunctivitis with the unusual finding of subacute rhabdomyolysis deep to the ulcerated conjunctiva. Immunoperoxidase staining of this biopsy for infectious bovine rhinotracheitis and Chlamydia were negative. Moraxella subgenus Branhamella ovis (Moraxella ovis), alpha hemolytic Streptococcus sp., and Arcanobacterium pyogenes were isolated from the conjunctival swab from cow #2424 and A. pyogenes and Streptococcus dysgalactiae ssp. dysgalactiae were isolated from cow #8108. Mycoplasma cultures were not performed. Additional biochemical and molecular analyses of the organism identified as M. ovis were performed as previously described (1,2). The results from this analysis indicated that the isolate was a recently characterized Moraxella spp., Moraxella bovoculi. Commonly used antibiotics in cattle to which the isolate of M. bovoculi was sensitive included ceftiofur, florfenicol, penicillin, and tetracycline.
For treatment, all affected cows were started on a once daily topical administration of an ophthalmic antibiotic ointment, containing oxytetracycline hydrochloride (Terramycin; Pfizer Animal Health, New York, New York, USA), for 3 consecutive days. Treatment did not require milk withdrawal. All cows recovered completely from the ulcerative lesions after approximately 2 wk; one cow (#2424) exhibited corneal opacity during recovery.
Conjunctival ulceration in adult cattle is a common presentation of squamous cell carcinoma; however, it is not associated with an infectious agent. Infectious bovine keratoconjunctivitis is the most common ocular disease of cattle and manifests as corneal ulceration and edema, blepharospasm, photophobia, and lacrimation. Instillation of hemolytic Moraxella bovis into the conjuctival sac of gnotobiotic calves lead to conjunctival erosions and ulcers at later stages of infection (3). In this affected herd, only 1 cow presented with corneal involvement characteristic of IBK along with the ulcerative palpebral/conjunctival lesions and it was not clear whether these represented distinct disease processes or not. Nevertheless, as only 1 cow exhibited both corneal and palpebral/conjunctival lesions, it seems most likely that this represented distinct disease processes. It is unknown, however, if the different lesions shared a common etiology.
Trauma was considered in the differential diagnosis; however, it was ruled out because the cows were housed in free-stall facilities as opposed to pasture, and several cows were affected, including one that had both eyes affected. Cows presented lesions at various degrees of progression, and the histopathology findings indicated an infectious process. Nonetheless, at the time that the cases of ulcerative blepharitis/conjunctivitis were diagnosed on this dairy farm, a severe infestation by stable flies (Stomoxys calcitrans) had also been noted on the farm; stable flies may have contributed to the initial injury and also transmission of any causal agents. That lesions were more prevalent in the lower eyelids (8/10 affected eyes), which have less mobility than the upper palpebrum, could support the putative involvement of biting flies.
Streptococcus dysgalactiae is a routinely isolated streptococcus from milk of mastitic dairy cows (4). Arcanobacterium pyogenes is commonly associated with endometritis and purulent abscesses in cattle (5). Although A. pyogenes and alpha hemolytic Streptococcus were isolated from the 2 cases that were cultured, it is not clear whether they were causal agents or normal flora. Previously, Streptococcus faecalis has been reported in equal proportions from both normal and IBK-affected eyes of cattle (6). The gram-positive organisms isolated from the ulcerative lesions of the cows’ eyes in this case series are not commonly associated with bovine ocular disease. Also, because S. dysgalactiae and A. pyogenes are ubiquitous in the environment of dairy cows and could readily colonize such lesions be they traumatic or infectious in origin, we suspect these isolates were not directly associated with the ulcerative lesions.
Moraxella bovis is recognized as the etiologic agent of IBK; however, a recently characterized species of Moraxella, Moraxella bovoculi, has been identified from corneal ulcers of beef and dairy calves in northern California (2). Along with M. bovis and M. bovoculi, infectious bovine rhinotracheitis (IBR) virus (7) and other bacteria such as Mycoplasma bovoculi (8), and Moraxella [Neisseria] ovis (9) have been associated with IBK. Of the various bacterial species and viruses associated with IBK in cattle, only M. bovoculi was isolated. Nevertheless, mycoplasma cultures were not performed in our cases and an involvement of mycoplasma cannot be ruled out. Previously, Moraxella bovoculi has only been reported in ulcerated eyes of calves with IBK and this is the first report of M. bovoculi associated with conjunctivitis in adult cows. Because M. bovoculi was isolated only from the cow with clinical signs of IBK (#2424), it is unknown if M. bovoculi was involved in the ulcerative conjunctival lesions, corneal lesions, or both. The sample from which M. bovoculi was cultured came from the subconjunctival cul-de-sac, and represented ocular fluid that contacted the entire ocular surface, including the ulcerated cornea. Further diagnostic workup of cases of ulcerative blepharitis/conjunctivitis in cattle should include aerobic as well as mycoplasma culture to more definitively determine the roles that various ocular bacterial pathogens of cattle may play in bovine ulcerative blepharitis/conjunctivitis.
To the authors’ knowledge this is the first report of ulcerative blepharitis and conjunctivitis in adult dairy cows. Furthermore, this is the first report of isolation of the newly described species M. bovoculi from adult cattle. The bacteria S. dysgalactiae and A. pyogenes were isolated from the 3 cases in which identification of bacterial or viral causative agents was attempted. This may indicate an opportunistic infection after an initial trauma which could have been inflicted by biting flies. In the cow that had a lesion characteristic of IBK, M. bovoculi was also isolated, thus indicating a possible association with the IBK lesions, the ulcerative lesions, or both. This report should increase the awareness of bovine practitioners and researchers regarding ulcerative blepharitis/conjunctivitis, as lesions may become severe but are amenable to treatment. CVJ
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