tramuscular oxytetracycline initially followed by 3g intramuscularly twice daily. It should be noted that once cows become recumbent the prognosis is much poorer with the majority dying. References Fredriksson G (1984) - Acta Vet Scand 25: 365 Frost AJ and Brooker BE (1986) - Aust Vet J 63: 327 Frost AJ, Hill AW and Brooker BE (1982) - Res Vet Sci 33: 179 Haynes RC and Murad F (1980) - The Pharmacological Basis of Therapeutics editors LS Goodman and A Gilman, 6th edn, MacMillan, New York Hill AW, Shears AL and Hibbitt KG (1979) - Res Vet Sci 26: 97 Murrav RD. Smith J and Harker DB (19811 - Vet Rec 108: 378 Welch-RAS; Crawford JE and Duganzich DM (1977) - N Z Vet J 25: 1 1 1 (Acepied for publication I4 June 1989)
mild to moderate, scattered neutrophilic infiltrate. Within the lung, a single large artery contained a neoplastic embolus (Figure 1). Similar discrete nests of neoplastic squamous cells were scattered within the pulmonary interstitium. A diagnosis of metastatic squamous cell carcinoma was made. Kowaris are predatory marsupials indigenous to the deserts of southwestern Queensland, Australia. To our knowledge, only a single previous report exists of a neoplasm in this animal, that being a schwannoma present in the axillary region of the left forelimb in a mature female (Hopkins and Gaynor 1985). The authors express their appreciation to Mr P Daly for preparation of the light photomicrographs. References Hopkins D and Gaynor B (1985)-Aust
Vet J 62: 340
(Accepted for publication 20 April 1989)
Glossal squamous cell carcinoma with pulmonary metastasis in a kowari @usyuroides byrnei) Department of Pathology, New York State College of Veterinary Medicine, Cornell University, Ithaca, New York 14853 Burnet Park Zoo, Syracuse, New York 13202
WI ANDERSON DN PETERS DA STOFFREGEN H STEINBERG C WALLACE
A 4-year-old female kowari (Dasyuroides byrnei) on exhibit at the Burnet Park Zoo, Syracuse, New York was initially examined for a swelling in the left mandibular region. The swelling had increased to 2.0 x 1.5cm over 2 weeks. Although the animal continued to eat well, significant weight loss occurred. Following surgical exploration of this area, the kowari died. A complete necropsy was performed. Tissues were fixed in 10% buffered formalin, processed routinely, sectioned at 4um and stained with haematoxylin and eosin. Histologically, within the tongue, discrete to coalescing nests, islands, and fronds of generally well differentiated squamous epithelial cells diffusely infiltrated the underlying lamina propria and extended into the tunica muscularis. A similar neoplastic infiltrate extended into the adjacent buccal mucosa. Vascular invasion was present. Within both the tongue and oral mucosa, necrotic keratin was present as was a
Closantel resistance in Huemonchus contortus from sheep Veterinary Laboratories NSW Agriculture and Fisheries Roy Watts Road Glenfield NSW 2167
PF ROLFE JC BORAY C FITZGIBBON G PARSONS
Pastures Protection Board Box 13, Warialda, NSW 2402 93
P KEMSLEY
Department of Veterinary Pathology, University of Sydney, Sydney, NSW 2006
The ability of closantel*, a salicylanilide anthelmintic, to control Haemonchus contortus at the recommended dose rate of 7.5 mg/kg, is an integral part of the strategic worm control program WORMKILL? (Dash 1986). This program has been highly successful in the summer rainfall areas of New South Wales. Closantel is unique among registered anthelmintics in that treatment removes worms present in sheep and provides sustained protection against reinfection (Hall el al 1981). Despite the widespread use of closantel and the previous use of a related drug, rafoxanide, resistance to closantel has not been reported in Australia although it has occurred in South Africa (Van Wyk and Malan 1988). Routine monitoring by faecal egg counts and larval culture had revealed the re-appearance of H. contortus in some sheep flocks on farms using WORMKILL. The presence of H. contortus infection was usually related to inadequate management such as incomplete mustering for treatment, unsecure boundary fences or under-dosing, but in other instances where management was adequate, the possibility of closantel resistance was investigated. Lambs aged 5 to 6 months that were free of helminths since birth were used in all the experiments. Isolates of H . contortus were either likely to be susceptible to closantel (McMaster laboratory strain and Armidale I1 field strain) or field strains with unknown susceptibility. The latter isolates were obtained when clinical haemonchosis was diagnosed despite the use of a previously effective strategic program; an increased percentage of H. contortus were recovered from cultures compared with previous routine monitoring; and where salicylanilides had been used extensively in the past for control of fasciolosis and haemonchosis. Field isolates were passaged in helminth free sheep to obtain infective larvae. Five thousand larvae of each isolate were given to each of 3 or 4 lambs. The lambs inoculated with
t Figure 1. Focal neoplastic embolus within a pulmonary artery (NE). Haematoxylin and eosin X 40
Australian Veterinary Journal, Vol. 67, No. 1 , January, 1990
N SANGSTER
Seponver. Smith Kline Animal Health Products, French’s Forest, NSW 2086 WORMKILL. A strategic drenching program for sheep in summer rainfall areas; NSW Agriculture & Fisheries, Pastures Protection Board and CSlRO 29
mild to moderate, scattered neutrophilic infiltrate. Within the lung, a single large artery contained a neoplastic embolus (Figure 1). Similar discrete nests of neoplastic squamous cells were scattered within the pulmonary interstitium. A diagnosis of metastatic squamous cell carcinoma was made. Kowaris are predatory marsupials indigenous to the deserts of southwestern Queensland, Australia. To our knowledge, only a single previous report exists of a neoplasm in this animal, that being a schwannoma present in the axillary region of the left forelimb in a mature female (Hopkins and Gaynor 1985). The authors express their appreciation to Mr P Daly for preparation of the light photomicrographs. References Hopkins D and Gaynor B (1985)-Aust
Vet J 62: 340
(Accepted for publication 20 April 1989)
Glossal squamous cell carcinoma with pulmonary metastasis in a kowari @usyuroides byrnei) Department of Pathology, New York State College of Veterinary Medicine, Cornell University, Ithaca, New York 14853 Burnet Park Zoo, Syracuse, New York 13202
WI ANDERSON DN PETERS DA STOFFREGEN H STEINBERG C WALLACE
A 4-year-old female kowari (Dasyuroides byrnei) on exhibit at the Burnet Park Zoo, Syracuse, New York was initially examined for a swelling in the left mandibular region. The swelling had increased to 2.0 x 1.5cm over 2 weeks. Although the animal continued to eat well, significant weight loss occurred. Following surgical exploration of this area, the kowari died. A complete necropsy was performed. Tissues were fixed in 10% buffered formalin, processed routinely, sectioned at 4um and stained with haematoxylin and eosin. Histologically, within the tongue, discrete to coalescing nests, islands, and fronds of generally well differentiated squamous epithelial cells diffusely infiltrated the underlying lamina propria and extended into the tunica muscularis. A similar neoplastic infiltrate extended into the adjacent buccal mucosa. Vascular invasion was present. Within both the tongue and oral mucosa, necrotic keratin was present as was a
Closantel resistance in Huemonchus contortus from sheep Veterinary Laboratories NSW Agriculture and Fisheries Roy Watts Road Glenfield NSW 2167
PF ROLFE JC BORAY C FITZGIBBON G PARSONS
Pastures Protection Board Box 13, Warialda, NSW 2402 93
P KEMSLEY
Department of Veterinary Pathology, University of Sydney, Sydney, NSW 2006
The ability of closantel*, a salicylanilide anthelmintic, to control Haemonchus contortus at the recommended dose rate of 7.5 mg/kg, is an integral part of the strategic worm control program WORMKILL? (Dash 1986). This program has been highly successful in the summer rainfall areas of New South Wales. Closantel is unique among registered anthelmintics in that treatment removes worms present in sheep and provides sustained protection against reinfection (Hall el al 1981). Despite the widespread use of closantel and the previous use of a related drug, rafoxanide, resistance to closantel has not been reported in Australia although it has occurred in South Africa (Van Wyk and Malan 1988). Routine monitoring by faecal egg counts and larval culture had revealed the re-appearance of H. contortus in some sheep flocks on farms using WORMKILL. The presence of H. contortus infection was usually related to inadequate management such as incomplete mustering for treatment, unsecure boundary fences or under-dosing, but in other instances where management was adequate, the possibility of closantel resistance was investigated. Lambs aged 5 to 6 months that were free of helminths since birth were used in all the experiments. Isolates of H . contortus were either likely to be susceptible to closantel (McMaster laboratory strain and Armidale I1 field strain) or field strains with unknown susceptibility. The latter isolates were obtained when clinical haemonchosis was diagnosed despite the use of a previously effective strategic program; an increased percentage of H. contortus were recovered from cultures compared with previous routine monitoring; and where salicylanilides had been used extensively in the past for control of fasciolosis and haemonchosis. Field isolates were passaged in helminth free sheep to obtain infective larvae. Five thousand larvae of each isolate were given to each of 3 or 4 lambs. The lambs inoculated with
t Figure 1. Focal neoplastic embolus within a pulmonary artery (NE). Haematoxylin and eosin X 40
Australian Veterinary Journal, Vol. 67, No. 1 , January, 1990
N SANGSTER
Seponver. Smith Kline Animal Health Products, French’s Forest, NSW 2086 WORMKILL. A strategic drenching program for sheep in summer rainfall areas; NSW Agriculture & Fisheries, Pastures Protection Board and CSlRO 29
