DERMATOPHILUS DERMATITIS (STREPTOTRICHOSIS) IN ONTARIO. 1. CLINICAL OBSERVATIONS* G. P. Searcyt and T. J. Hullandt INTRODUCTION lesced, and (iii) accumulation of cuta- neuos keratinized masses or cornified A DERMATITIS affecting cattle in the Bel- material forming "wart-like, bark-like gian Congo was described in 1915 by Van lesions" or "horn-like projections". Saceghem (46). The lesions were small Bovine streptotrichosis has also been but confluent, raised circumscribed crusts reported in Australia (1, 11, 26, 28), the on the skin composed of epidermal cells United States (6, 21, 30, 45), Canada (4) and coagulated serous exudate with em- and England (36). bedded hairs. He applied the name "Der- Streptotrichosis in horses has been matose Contagieuse" to the disease. The reported in Africa (16, 25), England (12, causative agent was said to be a bacterium 37, 42), and in the United States (4, 20). which could appear in two forms: (i) Kaplan and Johnston (20) described the Straight or curved filaments sometimes early lesions on horses as irregular patches branching and containing fine granules, of matted hair or as raised crusted areas, or (ii) Isolated cocci. with hairs protruding through the crusts. Van Saceghem named the organism Lesions in more advanced stages of de- Dermatophilus congolensis. In 1920, velopment were separated from the under- another report described a "Contagious lying epithelium. Removal of the crusts Impetigo" of cattle in Northern Rhodesia left a pink moist area or a soft smooth (20). Early lesions, usually noticed first skin. Branched hyphae divided in trans- on the back, resembled paint brushes due verse and longitudinal planes were demon- to matting of a few hairs. Scabs formed strated in smears prepared from scab with hairs protruding through them. When specimens. removed, they exposed a moist pinkish Mycotic dermatitis of sheep was reported surface which occasionally bled slightly. almost simultaneously in South Africa and The lesions would spread extensively over Australia by Bekker in 1928 and Seddon the body of susceptible animals and in 1929, respectively (3). Bull (7) first would coalesce. These animals often lost isolated and named the causal organism condition and died. Actinomyces dermatonomus. Lesions re- Streptotrichosis in African cattle was sembling those of streptotrichosis in cattle subsequently described by many workers have been described as affecting the lips, (8, 17, 27, 31, 38, 41, 47). Although ears, and coronets (17), but the majority various names were applied to the orga- of infections involve the wooled portions nisms demonstrated by these workers their of the body (3, 15, 29, 40). morphology resembled Dermatophilus In 1948, Harriss (14) described a derma- congolensis (Van Saceghem). titis affecting the legs of sheep in Scotland, Based on his observations of bovine known locally as "strawberry foot rot". The streptotrichosis in Africa, Szabuniewicz lesions were small, heaped up scabs situ- (43) distinguished three stages in the ated anywhere on the leg from the coronet development of the exudative dermatitis: to the knee or hock. Removal of the scabs (i) "matted together hairs" as "paint revealed fleshy masses with numerous brush" lesions (moist form), (ii) crust bleeding points. A gram positive filamen- or scab formation as the first lesions coa- tous organism which divided into parallel rows of cocci was proven later to be the *This work was supported in part by a causative agent (44). Medical Research Council of Canada Fellow- ship. Financial assistance from the Ontario Austwick (2) made the first significant Department of Agriculture and Food for this attempt to classify the Dermatophilus project is gratefully acknowledged. organisms and the diseases associated with fOntario Veterinary College, University of them. He proposed the following nomen- Guelph, Guelph, Ontario. clature: 7 CAN VET. JOUR., VOl. 9, no. 1, January, 1968 CANADIAN VETERINARY JOURNAL Order Actinomycetales access to shelter. The remainder of the Family Dermatophilaceae premises were dairy farms and the hus- Genus Dermatophilus bandry practises were, in general, good. Species Dermatophilus congolensis On farms where several animals were Cause of streptotrichosis in cattle, affected an attempt was made to deter- horses, sheep, goats, and elands. Dermatophilus dernatonamus mine the mode of transmission, but on Cause of mycotic dermatitis in most farms it was not possible to draw sheep any concrete conclusions. On premises Dermatophilus pedis 1112 the infection on every animal Cause of strawberry foot rot in appeared first under the lower jaw. The sheep. watering troughs consisted of steel drums which had been cut into halves. The edges Recent comparative studies on Dermato- philus organisms isolated from these vari- were uneven and sharp and may have been responsible for excoriation of the skin, ous diseases have led to the conclusion thus allowing Dermatophilus organisms to that there is only one species Dermatophi- produce a dermatitis. lus congolensis, in the genus Dermatophilus (13, 35). Although only one animal on premises 979 exhibited lesions, these were clearly CLINICAL OBSERVATIONS confined to a clipped area on the hind- quarters. During the period April 1, 1966 to On farms 978, 3183, and 3184 sucking cases of strepto- April 1, 1967, suspected lice (Linognathus vituli) were found on in horses and cattle were investi- trichosis the animals, and on farm 880 chorioptic animals were gated whenever possible. The mites were present in large numbers. on in south-western and farms located The distribution of lesions on cattle is central Ontario, within a 100-mile radius recorded in Table II. of Guelph. It must be emphasized that palpation was more important than visual inspection BOVINE STREPTOTRICHOSIS in obtaining an appreciation of the extent The incidence and seasonal occurrence of infection on an animal's body. of the disease on the various premises, The appearance of the lesions appeared as well as the ages of the animals, is re- to depend upon the length of time that corded (Table I). they had been in existence and are there- Premises designated as 704, 3183 and fore described as occurring in three 3184 were feedlots where the animals had different stages. TABLE I INCIDENCE AND SEASONAL OCCURRENCE OF DERMATOPHILUS INFECTION ON PREMISES AND AGE OF CATTLE Premises No. of animals No. of animals identification in herd affected Age Season 206 30 1 Mature WN'inter 697 25 1 " " 704 30 6 Yearling Winter and Spring 880 40 4 Mature \Winter 978 25 1 979 50 1 1112 25 10 " Summer 1265 30 1 1812 16 1 Yearling 2185 50 7 One month Autumn to mature 2348 30 2 Yearling 3089 40 1 Mature 3183 25 1 Yearling 3184 25 1 " " 3617 104 3 Mature Winter Total 545 41 8 DERMATOPHILUS DERMATITIS TABLE I I thicker and more darkly coloured scab. The DISTRIBUTION OF DERMATOPHILUS scabs were usually no larger than 1 cm. in l ESIONS ON CATTLE AND HORSES diameter. When adjacent apparently un- affected skin was rolled between the No. of animals fingers, thickening could often be detected. On premises 2185 the back of the udder Bodv area Cattle Horses was the only area of the body affected Head and neck 15 4 on several cows. On one animal, however, Back and sides 17 31 the skin over the medial surface of the Hindquarters 16 Udder 13 hind legs, adjacent to the udder, was also Legs 3 involved. Ventral abdomen 3 On premises 206, 2348, and 2185, pal- Generalized* 11 pation of other apparently normal cattle *All of the animals in which three or revealed an occasional small nodule on more areas on the animal were affected. one or two animals, they were usually located on the forequarters and neck, or along the back. Some were firm and dry Stage 1 while others were moist in the center. The first indication of dermatitis on Examination of material from these an animal was an erectness of the hair nodules usually revealed Dermatophilus into tufts. Palpation revealed roughening organisms in large numbers. of the surface of the skin and a greasy On premises 1112, 1265, 1812 and feeling at the base of the hair. 2185, the lesions never progressed beyond Inspection of the skin surface revealed Stage 1, as dehydration and sloughing a partially dried, to dry, serous exudate of the scabs occurred leaving an area of which was perforated by hair. As the alopecia. disease progressed this material formed crusts on the skin (Figure 1). These were Stage 2 often adherent and removal caused dis- Palpation at this stage revealed a very comfort to the animal. In such instances, roughened and thickened skin. The scabs the skin beneath the crusts would appear were greasy and often crumbled easily, moist and hyperemic with minor hemor- remaining loosely intact because of pro- rhage occurring in some cases. truding hairs. The best examples of lesions in their On casual inspection very little could early stages were those on the udders of be seen, especially if the hair coat was dairy cows where careful scrutiny revealed dense and long. Closer inspection, how- a thin layer of dried serous exudate at the ever, revealed dirty yellow scabs perfo- base of the hair. These lesions were sub- rated by a variable number of hairs ject to abrasion when located on the (Figure 2). When these lesions were lower part of the udder, resulting in a diffuse, slight fissuring of the underlying skin occurred over flexural surfaces. Crusts on the skin of the escutcheon of a cow are illustrated in Figure 3. FIGURE 1. Crusts from a cow with strep- FIGURE 2. Crusts on the nose of a steer totrichosis (Stage 1). (Stage 2). 9 CANADLAN VETERINARY JOURNAL In generalized chronic cases of bovine streptotrichosis, thick horny scabs often were confluent forming a mosaic pattern (Figures 5, 6, 7 and 8). r IGURE 5.