Epidemic caprine keratoconjunctivitis: recovery of Mycoplasma conjunctivae and its possible role in pathogenesis

Abstract

Clinical, microbiological, serological, histological, and therapeutic aspects of two separate outbreaks of caprine keratoconjunctivitis are described. The disease was characterized by a high rate of contagion, rapid onset, intense lacrimation, conjunctival hyperemnia, and corneal opacity with neovascularization. In addition, many of the animals developed respiratory illness during the second epidemic. The only organism consistently isolated was Mycoplasma conjunctivae. A total of 23 strains were isolated from 18 inflamed conjunctivae, one normal conjunctiva, and the nasal secretions of four goats with concomitant respiratory illness. The convalescent sera of goats in the first outbreak had neutralizing antibody titers to M. conjunctivae that ranged from 1:32 to 1:256. In the milder second outbreak the antibody titers ranged from 1:4 to 1:32 in animals with only ocular disease and from 1:4 to 1:64 in animals with only respiratory disease. Whereas little change was noted in antibody titers of goats with only localized eye disease, 43% of the goats with respiratory disease showed significant fourfold rises. The histological picture was consistent with acute corneal infection. Animals requiring antibiotic treatment appeared to respond favorably to a combination of oxytetracycline and polymyxin B, but not to penicillin. These findings suggest that M. conjunctivae is one cause of epidemic caprine keratoconjunctivitis.

Epidemic caprine keratoconjunctivitis: experimentally induced disease with a pure culture of Mycoplasma conjunctivae

“…This study describes the successful induction of severe keratoconjunctivitis in goats inoculated with a cloned culture of M. conjunctivae. The course of the experimentally induced disease was similar to the disease observed during two spontaneous outbreaks of caprine keratoconjunctivitis (2). The successful induction of disease has permitted us to meet Koch's postulates and to suggest that M. conjunctivae is one cause of epidemic caprine keratoconjunctivitis.…”

“…The factors that permit mycoplasmas to colonize tissues for extended periods of time are not well understood. However, persistence may help to explain the occurrence of sporadic endemic disease and also of relapse in some animals, phenomena observed during our study of the disease (2).…”

“…The lymphocytes of goat 513 showed a threefold response for M. conjunctivae before challenge, suggesting a previous experience with the organism, which may have influenced the resulting mild course of the induced infection. DISCUSSION M. conjunctivae has been isolated by a number of investigators from the inflamed eyes of goats, sheep, and chamois with keratoconjunctivitis during epidemics in geographically distant countries (2,4,(10)(11)(12)(13)(14)(15). In 1969, Klingler et al (10) isolated a mycoplasma from the eye of a chamois with keratoconjunctivitis.…”

“…A variety of mycoplasmas have been isolated from goats with keratoconjunctivitis, including Mycoplasma arginini, Mycoplasma conjunctivae, and Acholeplasma oculi (1,2,4,12). M. conjunctivae has been implicated as a cause of keratoconjunctivitis because it has been frequently isolated from the inflamed eyes of goats, sheep, and chamois during separate and distant epidemics occurring in Maryland (2, 4), Canada (11), Australia (14, 15), and Switzerland (10,12,13).…”

Detection and Identification of Mycoplasma conjunctivae in Infectious Keratoconjunctivitis by PCR. Based on the16S. rRNA. Gene

“…Infectious keratoconjunctivitis (IKC), commonly known as pink-eye, is a contagious disease of domestic ruminants, localized in the eyes and characterized by inflammation of the conjunctiva and cornea (JONES, 1976, BAAS et al, 1977, BARBER, 1986. In the European Alps, IKC occurs frequently also in both free-ranging alpine ibex (Capra ibex ibex) and chamois (Rupicapra rupicapra rupicapra) .…”