Inclusion keratoconjunctivitis ('pink eye') in sheep

Summary

The cytoplasnwtic inclusion bodies, which, in 1931. Coles discovered in the corneal cet. of sheep suffering from contagious keratoconjunctivitis arc now considered to be the reticulate bodies of a chlamydia. Colesiota conjunctivae (synonym: Chlamydia psittaci ovis).

According to the postulates of Koch Colesiota conjunctivae is a primary cause of contagious kerato‐conjunctivitis in sheep, but the clinical picture is complex and is a result of the interaction between the infecting chlamydiae. host resistance factors. and secondary infections caused by opportunistic bacterial ocular pathogens.

The clinical syndrome might also be caused by other micro‐organisms, such as Mycoplasma conjunctivae or environmental factors, such as dust. However, in these cases, cytopiasnwtic inclusion bodies cannot be found in the corneal cells of diseased eyes.

To differentiate chlamydial keratoconjunctivitis from keratoconjunctivitis due to other causes, it is proposed to include in the name the laboratory findings typical for this disease: Sheep Inclusion Keratoconjunctivitis.

Chlamydia are Gram‐negative bacteria, which arc obligate intracellular parasites.

Prolonged treatment seems to be required to eradicate chlamydiae from a host and antibiotics must reach intracellular levels that are higher than their minimum inhibitory concentration for chlamydiae. Tetracyclines are the drugs of choice. This means that for a microbiological cure, diseased sheep must be injected several times a day for a week or more. Because the disease is usually self‐limiting and economic losses are considered low, this seems unnecessary and control of the disease by local treatment of secondary infections .seems sufficient.

However, this will not prevent .spreading of the disease in a herd and relapses may occur.

Notes

Centrali.sed Experimental Animal Facilities and Department of Medical Microbiology, University of Limburg, P.O. Box 616, 6200 MD Maastricht, the Netherlands.