NECROBACILLOSIS IN DEER AND PRONGHORN ANTELOPE IN SASKATCHEWAN G. Wobeser, W. Runge and D. Noble*

INTRODUCTION (G.W. and D.N.) visited the ranch. The area within approximately 3 km of the feeding yard Sphaerophorus necrophorus infection has been was searched from the air (fixed-wing aircraft recognized in many species, and causes great flown at approximately 100 m), and on the economic loss among domestic livestock ground with snowmobiles. Approximately 100 (14). The occurrence of necrobacillosis among live deer were observed in the area; of these, wild animals has been reviewed by Rosen (10). two deer fawns and one mule deer Epizootics of necrobacillosis have been reported fawnwhite-tailed to be extremely weak and relucappeared in mule deer (Odocoileus hemionus) in Cali- tant to move. Twenty dead deer were found; of fornia (11), elk (Cervus canadensis) in ten (six white-tailed and four mule Wyoming (1, 7), and Rosen et al (11) stated which, were brought to Saskatoon for necropsy, deer) that "epizootics [of necrobacillosis] sweep and the ten (one white-tailed and through the reindeer population of Siberia". nine muleremaining were examined in the field. deer) The disease was first recognized among Calilatter animals had been partially consumed fornia mule deer in 1924 during an outbreak in The scavengers, so that complete necropsies were by which several hundreds of deer died (11). not possible. Almost all of the dead deer were Between 1924 and 1951, "California has had a located within 0.5 km of the feeding yard. continuous history of the disease", with xeric Approximately 600 sheep and 200 cattle were regions of the coast range being enzootic areas maintained on the ranch. As many as 40 deer (11). Murie (7) estimated that 5.8% of the had been present the feeding yard all 7,000 elk concentrated on a winter feedlot in winter, feeding in about and a fenced area around Wyoming during one winter died of disease, containing piles of baled green oats alfalfa primarily necrobacillosis. More than 1,000 elk hay, and a granary containing barley.andMany of died in a later epizootic in the same herd (1). the deer had appeared very weak and could Epizootic necrobacillosis has not been preapproached closely. Several porcupines viously reported among wild animals in Canada, be (Erethrizon dorsatum) had lived in the baleand has apparently not been recognized in stacks all winter. The rancher had not exwhite-tailed deer (Odocoileus virginianus). perienced any problem with footrot among the cattle and sheep, and could only recall two cases in cattle during the past few years. HISTORY AND METHODS On April 18, 11 dead pronghorn antelope On February 18, 1974 six white-tailed deer (Antilocapra americana) were sighted from the and one mule deer were submitted for necropsy air, about 3 km from the ranch. On April 20, the to the Western College of Veterinary Medicine. area was visited and six additional dead antelope The deer had been found dead by personnel were found. Three of these animals were sulb of the Department of Tourism and Renewable mitted for necropsy. Prior to necropsy the animals were identified Resources on a sheep and cattle ranch located in an area known as the Cabri Sandhills in as to species and sex, weighed, and age was southwestern Saskatchewan. On March 24, the estimated on the basis of tooth eruption and ranch was revisited and 14 dead deer were wear (13). Necropsies were performed and found in the immediate area of a yard used for tissues collected for bacteriological examinafeeding cattle. Eight of these deer (five white- tion. Impression smears of lesions were stained tailed and three mule deer) were submitted for with gram stain. Tissues were cultured on sheep necropsy. On April 10, two of the authors blood agar and MacConkey agar incubated in air at 37°C. Representative tissue sections were fixed in 10% neutral buffered formalin, emDepartment of Veterinary Pathology, Western College of Veterinary Medicine, University of bedded in paraffin, sectioned at 6 ju and stained Saskatchewan, Saskatoon, Saskatchewan (Wobeser) with hematoxylin-eosin. Brown-Brenn gram and Department of Tourism and Renewable Re- stain was employed in selected cases. The moisture and fat content of femur sources, Province of Saskatchewan, Saskatoon, Saskatchewan (Runge and Noble). marrow were measured as indicators of body 3 CAN. VET. JoUR., vol. 16, no. 1, January, 1975

CANADIAN VETERINARY JOURNAL TABLE I

DISTRIBUTION AND OCCURRENCE OF LESIONS IN 17 WHITE-TAILED DEER, NINE MULE DEER AND Two PRONGHORN ANTELOPE WITH NECROBACILLOSIS Number of animals with lesion White-tailed

Mule

Deer

Deer

14

8

Lesion

Stomatitis Rumenitis Hepatitis Mandibular osteomyelitis

Pneumonia

Pharyngitis Laryngitis Omasitis Reticulitis Arthritis and periarthritis Pododermatitis

Pronghorn

Antelope

1

9 5 8 4

5 1 1

-

-

-

1

3 -

2 1

-

-

-

-

1

3

1

1

-

1

TABLE II SEX AND AGE OF DEER AND ANTELOPE EXAMINED, BRACKETED NUMBERS INDICATE ANIMALS WITH LESIONS OF NECROBACILLOSIS Age (to nearest year)

Species

Sex

White-tailed deer

M

F Mule deer

M F

Pronghorn antelope

M

AND

2

3

4

5(5)

2(2) 2(2) 1(1)

1(1)

1(0)

4(4) 9(4) 6(3)

F

DISTRIBUTION

1

1(0)

1(1)

-

-

5 1(1)

1(1)

1(1)

1 (adult, not aged) (1)

1(1)

TABLE III OF LESIONS IN THE ORAL CAVITY OF DEER WITH NECROBACILLOSIS

INCIDENCE

Number of deer with lesion

Site

Tongue Mandibular symphysis Interalveolar area Premolar and molar region Angle of mandible Hard palate Pharynx

condition' and hepatic vitamin A levels were determined in five cases using the method of Davies (5). GROSS LESIONS Macroscopic lesions of necrobacillosis were present in 17 of 18 white-tailed deer, nine of 17 mule deer and two of three antelope

White-tailed deer 8

Mule deer

5 3 3

0 1 1 6 2 3

4

3 0

3

examined, respectively (Table I). Included

among the 17 mule deer, were nine animals necropsied in the field. Of these, the intact carcass was present in only four cases, the remaining five deer having been partially consumed by predators. The majority of the animals necropsied were fawns from the previous spring but lesions were found in animals of all ages (Table II). The most frequently 'Analyses performed by Feed Testing Laboratory, occurring lesions were necrotic foci in the oral Department of Animal Science, University of cavity (Table I). The distribution of lesions Saskatchewan, Saskatoon. within the oral cavity is shown in Table III. 4

NXECROBACILLOSIS

had extended from the vertical ramus of the mandible through soft tissue to produce osteolysis of the sphenoid bones. Necrosis and osteomyelitis of the mandible were present in nine deer and one antelope. These lesions had frequently resulted in loss of either incisor or cheek teeth (Figure 4), and in some cases the missing teeth were found in the forestomachs. Ruminal lesions were characterized by well demarcated, yellow raised foci of necrosis (Figure 5), which were most prominent on the

,/~~~~~~~~~~~~~~~~~~~~r- ..-W5Wa_ FIGURE 1. White-tailW deer with necrobacillosis, necrosis and sloughing of tongue.

FIGURE 3. Lateral view of head of white-tailed deer with necrobacillosis. Necrotizing process extends from angle of mandible dorsal on gingivial margin of maxillary molar teeth. Note embedded plant fibres.

! .'.- xv

t,

..

I i

F,

I

..

..

.1 1 ;. . :!

.!

"

i. I ,r

FIGURE 2. Cross section of tongue of mule deer with necrobacillosis. Note that the necrotic process is present beneath apparently normal mucosa (arrow). Lesions in the tongue ranged from necrosis with sloughing of the distal portion (Figure 1) to large circumscribed foci within the tongue at the level of the transverse groove (Figure 2). The ventral area of the tongue was usually the most severely affected region. Lesions often extended from the angle of the mandible (Figure 3) to the hard palate, and in several cases the necrotizing process extended dorsally along the vertical ramus of the mandible. In one white-tailed deer the necrotizing process

FIGuRE 4. Mandible of white-tailed deer with necrobacillosis. Necrotizing osteomyelitis, with loss of a molar tooth, and necrosis of mucosa at angle of mandible (arrow). 5

CANADIAN VETERINARY JOURNAL

(Figure 7). All of these animals had necrotizing lesions in the oral cavity. One deer had focal 2 to 3 cm diameter areas of necrosis and haemorrhage scattered diffusely throughout the lung. The other deer had a combination of the two types of pulmonary lesion and also had necrotic stomatitis. Both animals with diffuse pulmonary involvement had necrotic foci in the liver. Necrotic laryngitis was present in one whitetailed deer, and three mule deer had necrotic lesions in the pharynx. The latter lesions were associated with Cephenemyia sp. larvae which had burrowed deep in the submucosa of the pharynx. Arthritis and periarthritis of the hock joint with multiple draining fistulous tracts was found in one deer, and pododermatitis was present in one antelope. Severe dermatitis and phlegmonous inflamFIGURE 5. Rumen of white-tailed deer with mation of the subcuticular tissues of the hind necrobacillosis. Multiple raised yellow necrotic foci limbs in association with embedded porcupine are evident on the rumen pillars. quills was present in three deer and one antelope (Figure 8). The body condition of the animals with necrobacillosis ranged from severely emaciated,

FiGuRE 6. Cross section of liver of white-tailed deer with necrobacillosis. Large areas of caseous necrosis are evident.

pillars, but also occurred in papillary areas. The foci extended deep into the wall of the rumen, and in one case, the lesions had perforated the wall leading to peritonitis. Dry caseous necrotic foci up to several cm in diameter were present in the liver of six deer (Figure 6). All of these deer also had lesions in the rumen. Necrotic lesions were found in the lungs of seven deer and one antelope. In five of the deer and the antelope these were restricted to the FIGURE 7. Cross section of anterior portion of anterior-ventral regions of the lungs, with lung of white-tailed deer with necrobacillosis and fibrinous pleuritis, consolidation, haemorrhage aspiration The entire central area of and numerous foci filled with necrotic debris the section pneumonia. is composed of necrotic tissue. 6

NECROBAcniLOSIS

rounding the areas were thrombosed. The lesions often expanded in the submucosal area with excavation of submucosal tissue beneath intact mucosa at the margins. Small foci of rumenitis characterized by vacuolation of epithelium with neutrophil infiltration were found in four deer. Two of these deer also had larger necrotic foci present in the rumen. The pulmonary lesions were of two types. Six deer and one antelope had aspiration pneumonia with necrosis, haemorrhage and neutrophil infiltration centred around bronchioles plugged with necrotic debris in which plant material was evident. The diffusely scattered focal lesions present in the lungs of two deer were foci of necrosis surrounding thrombosed vessels in which numerous bacteria were evident. Verminous pneumonia of various degrees of severity, with interstitial reaction and numerous nematode larvae and ova present in alveoli was found in all mule deer fawns and antelope examined. BACTERIOLOGICAL AND ANALYTICAL FINDINGs A variety of organisms was isolated from the necrotic lesions cultured. The most commonly isolated organism was Corynebacterium pyogenes; other frequently isolated organisms were Pasteurella multocida and Escherichia coli. Staphylococci and Streptococci were found occasionally. Sphaerophorus necrophorus was not isolated; however, large numbers of gram negative, beaded filamentous organisms were consistently present in impression smears of necrotic lesions. The vitamin A level in the liver of five deer with lesions of necrobacillosis ranged from 20.7 to 113.0 ug vitamin A/g of liver, with a mean of 62.0 /Lg/g.

FIGURE 8. Hind limb of white-tailed deer. Note swelling, exudate and numerous embedded porcupine quills.

to animals with plentiful fat reserves. In general, fawns of the previous spring were emaciated, while older deer were in better body condition. The cause of death of five mule deer necropsied in the field was not determined. Lesions of necrobacillosis were not found in the tissues available. Four deer died from causes other than necrobacillosis. A four-year-old male white-tailed deer found approximately 3 km from the feeding yard had diffuse fibrinous peritonitis as a result of perforation of the reticulum by a twig. DIsCUSSION The other three deer were mule deer fawns all of which were severely emaciated. The lungs The range of lesions observed in the present of these animals were plum grey in color, outbreak was similar to that reported in deer spongy on palpation, with froth and many dark( 10, 11 ) and elk ( 1, 7), although footrot, which colored lungworms (Protostrongulus sp.) in the was a common finding in California deer (11), airways. One of these deer had a fractured was not seen among the deer; however, lesions humerus. similar to those reported by Chalmers and Barrett (4) were found in one antelope. Fawns comprised a large proportion of the HISTOPATHOLOGICAL LESIONS animals involved in the present outbreak, as The lesions in the oral cavity, rumen, and has been the case in previous outbreaks (7, 10), liver were similar in all deer, with large areas but it is not known whether this was because of coagulation necrosis containing masses of of greater susceptibility of young deer, or filamentous gram-negative bacteria. There were represented the age distribution witlhin the few inflammatory cells present about the population at the feeding yard. necrotic foci, but many vessels within and surSphaerophorus necrophorus was not isolated;

7

CANADIAN VETERINARY JOURNAL

however, the gross and histopathological lesions, and the morphology of organisms present in impression smears from lesions is strong presumptive evidence for the diagnosis of necrobacillosis. It appeared that in most cases, mixed populations of microorganisms were present in the lesions, with C. pyogenes occurring very frequently. Special techniques such as rabbit inoculation would likely be necessary to isolate S. necrophorus from such mixed infections (14). The common occurrence of mixed infections of C. pyogenes and S. necrophorus is interesting in view of the pathogenic synergy of these species reported by Roberts (8, 9). Roberts (8) stated that S. necrophorus is likely the "primary invasive and necrotizing agent" in these mixed infections and that it facilitates the establishment and growth of C. pyogenes in tissue. The epizootiology of necrobacillosis outbreaks in wild ungulates is poorly understood. Crowding of animals about waterholes or feeding areas was a feature common to outbreaks among deer in California (11), elk in Wyoming (1, 7), and the present situation. Overbrowsing of available natural forage was also reported in both previous situations (7, 11) and was very evident in the area surrounding the feeding yard in this case. Epizootics in deer in California occur during the summer, and are of greater severity in years of drought (11). In contrast, the outbreaks in elk and the present cases occurred during the winter. In California and the present situation wild ungulates shared range with sheep and cattle. Rosen et al (11) reported that an outbreak occurred in a deer herd previously free of the disease within two weeks of the introduction of cattle infected with footrot to the range. Footrot was apparently an uncommon occurrence among the cattle and sheep on the ranch where the present dieoff occurred. Sphaerophorus necrophorus is generally considered to be unable to breach intact mucosa (6), and sharp or coarse plant material such as grass awns has been implicated as a cause of the initiating lesions (7, 11). Barley awns were found embedded in oral lesions in three deer (Figure 3); however, it is impossible to state that awns were responsible for producing the initial lesion. Murie (7) reported a 7.5% incidence of the disease among 560 elk calves fed a diet of second-cut alfalfa and corn, suggesting that coarse plant material in the diet is not a prerequisite for the disease. Histopathological lesions in four deer were suggestive of chemical rumenitis, perhaps due to a diet (oat hay, barley) containing more carbohydrate than normal browse. Such lesions

might have provided a portal of entry for S. necrophorus in some deer. Cass (3) and Rosen (10) suggest that eruption of teeth might also provide the necessary entrance portal. All of the deer with necrotic lesions at the angle of the mandible were less

than two years of age; and would be likely to have teeth erupting in this area (13). Larvae of the deer nasal bot (Cephenemyia sp.) might also provide the initial damage. Necrotic pharyngitis was found in association with these parasites in three mule deer. It is our observation that Cephenemyia larvae produce only superficial lesions in the pharynx of white-tailed deer, but burrow deeply (1 cm or more) in the submucosa of the pharynx of mule deer. Rosen et al (11) cited earlier reports suggesting that vitamin A deficiency might be a contributing factor in necrobacillosis outbreaks. The levels of vitamin A present in the liver of the five deer examined were substantially higher than the level of 2.0 ,g/g of liver stated to be the critical level at which signs might appear in domestic animals (2), but "normal" levels for deer are unknown. The pulmonary lesions observed appeared to be due to aspiration of foreign material in animals with oral lesions, or embolism of septic material, probably from necrotic foci in the liver. Hepatic lesions likely represented metastasis from the rumen, since hepatic lesions were found only in deer which also had rumen lesions. At least 17 antelope died near the ranch, and necrobacillary lesions were found in two of the three animals examined; however, antelope had not been observed at the cattle feeding yard which seemed to be the focus of the deer dieoff. One of the antelope had numerous porcupine quills embedded in the skin of the hind legs, as did three deer found dead in the immediate vicinity of the feeding yards. It is speculated that the animals may have stepped upon, or kicked porcupines while feeding at the balestacks. Necrotic stomatitis has been previously reported in antelope by Rush (12), who found lesions in six of 13 antelope examined in the area of an outbreak in deer and elk. It is unknown how many animals died in the outbreak. A total of 40 deer and 17 antelope were found; however, it is likely that some were missed even during the aerial and ground search on April 10, and an unknown number of animals may have been consumed by scavengers prior to that time. Without an understanding of the epizootiology of the disease, control is impossible; and dispersion of animals away from crowded areas, and improvement of range to prevent concentration around water or feeding 8

NECROBACILLOSIS

areas as suggested by Rosen (10) may be the Medicine for their assistance, and A. Braaten, Abbey, Saskatchewan, for his cooperation. only practical methods available. REFERENCES SUMMARY 1. ALLRED, W.J., R.C. BROWN and O.J. MuRIE. Necrobacillosis was diagnosed in 17 of 18 Disease kills feed ground elk. Wyoming Wildlife 9: 1-8. 1944. white-tailed deer, nine of 17 mule deer and two of three -pronghorn antelope found dead 2. BLOOD, D. C. and J. A. HENDERSON. Veterinary Medicine. 3rd Ed., p. 738. London: on a ranch in southwestern Saskatchewan during Bailliere, Tindall and Cassell. 1968. the period February to April 1974. Diagnosis 3. CASS, J. S. Bucchal food impaction in whitewas based upon gross and histopathological tailed deer and Actinomyces necrophorus in lesions, and the morphology of organisms big game. J. Wildl. Mgmt 11: 91-94. 1947. present in impression smears of lesions. At least 4. CHALMERS, G. A. and M. W. BARRETT. Infec40 deer and 17 antelope died in the area, but tious pododermatitis in a pronghorn antelope in Alberta. J. Wildl. Dis. 10: 60-62. 1974. no disease was reported among approximately 600 sheep and 200 cattle sharing the range. 5. DAVIES, A. W. The colorimetric determination of vitamin A by the alkali digestion History, field observations and pathology of the Biochem. J. 27: 1770-1774. 1933. disease are described, and the epizootiology is 6. method. JUBB, K. V. F. and P. C. KENNEDY. Pathology discussed. of Domestic Animals. Vol. II. 2nd Ed. p. 38. New York: Academic Press. 1970. 7. MuRuE, 0. J. An epizootic disease of elk. J. Mammal. 11: 214-222. 1930. 8. ROBERTS, D . S. The pathogenic synergy of Fusiformis necrophorus and Corynebacterium pyogenes. I. Influence of the leukocidal exotoxin of F. necrophorus. Br. J. exp. Path. 48: 665-673. 1967. 9. ROBERTS, D. S. The pathogenic synergy of Fusiformis necrophorus and Corynebacterium pyogenes. II. The response of F. necrophorus to a filterable product of C. pyogenes. Br. J. exp. Path. 48: 674-679. 1967. 10. ROSEN, M. N. Necrobacillosis. In Infectious Diseases of Wild Mammals. J. W. Davies, L. H. Karstad and D. 0. Trainer, Editors. Chapter 28. pp. 286-292. Ames: Iowa State University Press. 1970. 11. ROSEN, N. M., D. A. BRUNETTI, A. I. BISCHOFF and H. A. AZEVEDO, Jr. An epizootic of footrot in California deer. Trans. North Am. Wildl. Conf. 16: 164-177. 1951. 12. RUSH, W. M. Northern Yellowstone elk study. Montana Fish and Game Comm. 1932. 13. TABER, R. D. Criteria of sex and age. In Wildlife Investigational Techniques. H. S. Mosby, Editor. Chapter 6. pp. 119-189. Ann Arbour: Wildlife Society. 1963. 14. SIMON, P. C. and P. L. STOVELL. Disease of animals associated with Sphaerophorus necrophorus: Characteristics of the organism. Vet. Bull. 39: 311-315.1969.

Riksum Les auteurs ont pose un diagnostic de n6crobacillose chez 17 des 18 cerfs de Virginie, neuf des 17 cerfs mulets et deux des trois antilopes d'Amerique qu'ils trouverent morts sur un ranch du sud-ouest de la Saskatchewan, entre les mois de f6vrier et d'avril 1974. Leur diagnostic s'appuyait sur les lesions macroscopiques et histologiques, ainsi que sur la morphologie des microbes qu'ils decelerent dans les impressions preparees a partir des lesions. Au moins 40 chevreuils et 17 antilopes moururent dans cette region; on ne signala cependant aucune maladie chez les quelque 600 moutons et 200 bovins vivant sur le meme territoire. Les auteurs decrivent l'anamnese, leurs observations cliniques et la pathologie de cette maladie; ils en commentent aussi l'epizootiologie. ACKNOWLEDGMENTS The authors wish to thank D. Dobson, E. Scoville and I. MacMurchy of the Department of Tourism and Renewable Resources for their help in the field work, members of the Departments of Veterinary Microbiology and Veterinary Pathology, Western College of Veterinary

9