Page 20 - ACV Journal DECEMBER 2015
P. 20
Scientific
DERMATOPHILUS CONGOLENSIS
INFECTION IN CATTLE
Andrew and Alison Havadjia
Following flooding in late winter and a wet spring, we had a number with a ‘tram-track’ appearance. Large numbers of Gram-positive
of clients report an unusual skin condition affecting their cows. cocci (the zoospores) were also present.
Adult cows, young heifers (15m)and even a 2-year-old steer were
reported to be affected. In most cases, only a single animal in each These findings, together with the clinical picture, were consistent
mob was affected. with a diagnosis of Dermatophilus congolensis infection.
All cases had generalised crusting and lumpy scabs over the The macerated crust material was inoculated onto sheep blood
entire animal, including the legs, with clumping and matting of the agar and incubated at 35° C in a candle jar, to enhance the CO₂
associated hair (see photos). The hairy crusts varied in size from 0.5 environment (after a quick trip to town to buy a suitable candle – the
to 2 cm in diameter. They could be fairly easily removed, leaving an scented ones also have the advantage of sweetening the not-so-
ulcerated area on the skin. The lesions appeared similar to rain scald sweet smell of growing organisms!). After 24 hours, small, cream
commonly observed in horses, but I had never seen this condition in coloured, haemolytic colonies were present on the agar. After 48
cattle in our area before. hours, the colonies were obviously indented into the agar and difficult
to remove. As the colonies aged further, they became wrinkled and
At the clinic laboratory, part of a crust was softened in a small more yellow – all the classical features of D.congolensis.
amount of distilled water and left to sit for a while. Smears were
made and stained with Gram stain. On examination, these revealed All animals were given a course of penicillin for 7 days and made a
numerous Gram-positive, filamentous, branching organisms, often full recovery.
20 The Australian Cattle Veterinarian | volume 77 | December 2015 www.ava.com.au/cattle
