Progress 07/01/01 to 03/01/05
Outputs
Validation of ear notch testing to detect BVDV-infected cattle. Veterinary laboratories test large numbers of cattle using ear-notch tests to distinguish acutely from persistently infected animals. Sixty-seven BVDV-infected calves were detected in three Wyoming herds. Calves were donated to WSVL. Over 3 months, all were tested repeatedly by 5 laboratory methods (RT-PCR, IHC, AgELISA, serology and virus isolation) to determine sensitivity, specificity, and positive/negative predictive value. Fifty nine calves (88%) were persistently infected with BVDV. Three acutely infected calves remained positive by IHC for 3 consecutive months. This is the first study to demonstrate accuracy and effectiveness of AgELISA on ear notches. Report published. Rabies surveillance: We participated in experimental bait acceptance study directed by USDA-Wildlife Services. The aim was to determine whether baits used to control rabies in raccoons are accepted by skunks. In a companion study, an
active skunk rabies surveillance program was instituted statewide in WY. Seventeen animals from each of Wyoming's 23 county are collected and tested for rabies annually Adverse reaction to commercial vaccines: In the absence of a transparent post-marketing surveillance scheme for veterinary vaccines, we investigated post-vaccination lameness in a 469 cow herd vaccinated with two USDA-approved vaccines. Lameness was attributed to the irritating nature of the vaccines, and vaccination too near to parturition. Report published. Novel spontaneous diseases: Aspects of two novel diseases were investigated, characterized and published. A congenital encephalopathy with status spongiosus in newborn calves was characterized. Bone lesions in inbred Salers cattle with inherited hemochromatosis were defined. Reports published.
Impacts
1. A commercial antigen-ELISA detecting BVDV-infected cattle was validated. In 2006, six states including WY submitted proposal to USDA's NRI program to develop a voluntary BVDV elimination program. 2. The prospective WY-wide study of rabies in trapped skunks is used to increase public education about rabies and decrease exposures, and predict hot-spots of rabies in Wyoming. The bait vaccination study of skunks, if successful, will provide wildlife managers with an additional tool to control rabies in endemic rabies areas.
Publications
- Cornish, T.E. et al: 2005, J Vet Diagn Invest. 17(2):110-117
- O'Toole, D. et al: 2005, J Vet Diagn Invest 17(1):23-31
- O'Toole, D. et al.: 2005, J Vet Diagn Invest 17: 546-553
- Nordin, R.W. et al.: 2004, Vet Pathol. 2004 41(6):612-623
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Progress 01/01/02 to 12/31/02
Outputs
In conjunction with the WVMA and Wyoming Beef Council, the department implemented on-line training for Beef Quality Assurance to decrease injection site lesions and eliminate residues in beef. To date, 49 trainers have been certified and 218 producers/ranches have been certified in Wyoming. This web site is in conjunction with the Wyovet (http://wyovet.uwyo.edu) Web site that enables practitioners to access animal disease case information 24 hrs/day from WSVL. A special disease alert section highlights diseases such as WNV, CWD, and BVD for both veterinarians and producers.
Impacts
The immediate impact has been to reduce losses from ongoing disease problems by developing methods to more readily detect disease (e.g. the PCR for diagnosis of diarrhea cases). Longer term, a better understanding of these diseases will allow for better test development as well as improved control measures. Reduction of Brucella infections in elk may reduce opportunity for transmission to livestock and humans. Investigation of MCF disease outbreaks in bison establishes that it is the leading cause of acutely fatal losses in many herds of commercial bison. Even brief contact (<24 hr) with infected sheep cause heavy losses (mortality of >25% of herds) over subsequent months. These investigations underscore the importance of continuing efforts by UW and WSU to isolate the causative virus and understand natural transmission patterns. Hemochromatosis is an animal model of a common, fatal human disease. Collaborative work on the genetic basis for the disease is ongoing with
a human hemochromatosis laboratory in the United Kingdom, and may improve understanding of diseases associated with iron overload in both animals and people.
Publications
- No publications reported this period
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Progress 01/01/01 to 12/31/01
Outputs
The Department of Veterinary Sciences researchers investigated a variety of animal health-related problems. A major thrust of those efforts has investigated diseases that impact reproduction and immunity in livestock. BVD vaccination of dams and the evaluation of fetal protection is still in progress. The incidence of Malignant Catarrhal Fever (MCF) in bison is under investigation with transmission studies in progress. New testing methods have been implemented in the virology, bacteriology and parasitology laboratories that allow for the rapid identification a wide range of pathogens. Veterinarians and producers were informed of the addition of a new diagnostic test to detect persistently infected cattle via presentations and lay publications. A cooperative effort between the Department of Veterinary Sciences and the Wyoming Game and Fish Department has resulted in development and validation of a blood test to distinguish between elk that are infected with Brucella
abortus and elk that have been immunized against this infectious agent. The assay will enhance efforts to reduce the prevalence of brucellosis in elk by the immunization of young animals and is currently being used by Wyoming Game and Fish. The occurrence and epidemiology of malignant catarrhal fever (MCF) in a large bison feedlot in Kansas was investigated, documented and reported. MCF was the leading cause of death in the yard. Retrospective studies by PCR on archived tissues established the disease was present since 1993. In a collaborative study with the University of Saskatchewan, the epidemiology of another large outbreak of MCF, in bison exposed to sheep at a sale barn, was investigated. A study to establish whether bison persistently infected with the MCF virus transmit infection to other ruminants is underway at the WSVL in collaboration with Washington State University researchers. An inherited disease of the liver of Salers cattle, hemochromatosis, was reproduced in a
breeding study. Lesions due to preclinical hemochromatosis in bone were documented and reported. The features of a papular dermatitis induced in guinea pigs by biting midges was characterized, in collaboration with the USDA's Arthropod-borne Animal Disease Laboratory. A large outbreak of ringworm was investigated in a commercial flock of sheep in Oklahoma. Clinical signs and lesions were consistent of club lamb disease, but attempts to culture the organism were unsuccessful. The relationship between brand scar keratoma and the development of squamous cell carcinoma in hot-branded adult cattle was investigated and results have been submitted for publication. The WSVL investigated a case of hydrocarbon poisoning in a herd of approximately 300 cows. The case was unusual in that the predominant clinical signs were neurological and the cause of poisoning was highly volatile fractions from natural gas condensate. Salt poisoning resulted in the deaths of 6 of 110 bulls and prolonged illness
in 5 or 6 more. Environmental investigation indicated that, despite the fact that principle water supply was treated municipal sewage, the direct cause of the episode was failure to provide enough watering holes in the ice.
Impacts
The immediate impact has been to reduce losses from ongoing disease problems by developing methods to more readily detect disease (e.g. the PCR for diagnosis of diarrhea cases). Longer term, a better understanding of these diseases will allow for better test development as well as improved control measures. Reduction of Brucella infections in elk may reduce opportunity for transmission to livestock and humans. Investigation of MCF disease outbreaks in bison establishes that it is the leading cause of acutely fatal losses in many herds of commercial bison. Even brief contact (<24 hr) with infected sheep cause heavy losses (mortality of >25% of herds) over subsequent months. These investigations underscore the importance of continuing efforts by UW and WSU to isolate the causative virus and understand natural transmission patterns. Hemochromatosis is an animal model of a common, fatal human disease. Collaborative work on the genetic basis for the disease is ongoing with
a human hemochromatosis laboratory in the United Kingdom, and may improve understanding of diseases associated with iron overload in both animals and people.
Publications
- O'Toole, D., Kelly, E. J. , McAllister, M.M., Layton, A.W., Norrdin, R. W., Russell, W. C., Saeb-Parsy, K., and Walker, A.P. 2001. Hepatic failure and hemochromatosis of Salers and Salers-cross cattle. Vet Pathol 38 (4): 372 - 389.
- O'Toole,D. and Norrdin, R.W. 2001. Clinical course and histopathology of osseous changes in Salers hemochromatosis. AAVLD national meeting, Hershey, PA. Nov 2001. Abstract proceedings p. 9.
- O'Toole, D., Li, H., Sourk, C., Montgomery, D. H., Crawford, V. 2002. Malignant catarrhal fever in a bison feedlot 1994 - 2000. J Vet Diagn Invest.
- J. Berezowski, Middleton, D. M., O'Connor, B., Appleyard, G., West, K., Haigh, Woodbury, M., Crawford, T., Li, H., and O'Toole, D. 2001 Epidemiology of a large outbreak of malignant catarrhal fever in bison (Bison bison) following brief exposure to sheep at an auction sale. AAVLD national meeting, Hershey, PA. Nov 2001. Abstract proceedings p. 5.
- O'Toole, D. Research on MCF in bison: 2001 update. Colorado Bison Association. 2001. Colorado Springs, CO.
- O'Toole, D. Malignant catarrhal fever - the most important cause of acute fatalities in commercial bison. 2001. Colorado Veterinary Medical Association Convention, Steamboat Springs, CO. Proceedings, pp. 131 - 136.
- O'Toole, D., Bevier, D., Hunsaker, B., and Mills, K. 2001. Epidemic dermatophytosis (club lamb disease) in a flock of sheep. AAVLD national meeting, Hershey, PA. Abstract proceedings p. 54.
- O'Toole, D. and Woodard, L. 2001. BVD in Your Herd: Ear Today and Gone Tomorrow. Western Livestock Roundup.
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Progress 01/01/00 to 12/31/00
Outputs
The Department of Veterinary Sciences researchers investigated a variety of animal health-related problems. A major thrust of those efforts has investigated diseases that impact reproduction and immunity in livestock. For example, investigations found that vaccination for BVD has little effect on fetal calf immunity. The incidence of Malignant Catarrhal Fever (MCF) in bison has been investigated and found to be a major cause of losses in the feedlot. Tests under development include an immunohistochemistry assay for BVD in skin tissue and modern tests for trichomoniasis in cattle. In addition to study of infectious diseases, two major outbreaks of genetic disease were studied. In one instance, a series of calves were born with neurological disease. This unusual outbreak was traced to a single sire. In another instance, Salers-breed cattle were diagnosed as having hemochromatosis, a congenital iron metabolism defect in the liver. Follow-up breeding and genetics studies
were conducted in both cases. Environmental poisoning cases were also examined. One project investigated water deprivation in cattle and another is surveying edible fish for mercury and selenium levels.
Impacts
The immediate impact has been to reduce losses from ongoing disease problems by developing methods to more readily detect disease (e.g. the immunohistochemistry test for BVD) and to identify sires that produce genetic defects to hasten their removal from the herds. Longer term, a better understanding of these diseases will allow for better test development as well as improved control measures.
Publications
- D. O'Toole, E. J. Kelly, M. M. McAllister, A. W. Layton, R. W. Norrdin, W. C. Russell, K. Saeb-Parsy, Walker, A.P. 2000. Hepatic failure and hemochromatosis in Salers and Salers-cross cattle. Vet Pathol. (accepted for publication)
- D. O'Toole, H. Li, B. Dye, Crawford, T.B. 2000. Endemic infection of feedlot bison with OHV-2. 19th Annual Meeting, American Society of Virology, July 8 - 12, 2000. Fort Collins, CO. Abstract W47-10, p. 136 Proceedings.
- O'Toole, D., Li, H., Crawford, Crawford, T.B. 2000. The University of Wyoming and Washing ton State University and the United States Department of Agriculture your questions about Malignant Catarrhal Fever in bison. Smoke Signals - Official Publication of the Canadian Bison Association. XI (2): 18 - 25. Invited; 4 figs.
- O'Toole, D., Li, H., Montgomery, D.L., Sourk, C., Crawford, T.B. 2000. A prospective and retrospective study on ovine herpesvirus-2 malignant catarrhal fever. Bison World 25 (4): 20 - 21.
- Van Campen, H., Vorpahl, P., Huzurbazar, S., Edwards, J. and Cavender, J. 2000. A case report: Evidence for BVDV type 2-associated disease in beef herds vaccinated with a MLV-BVDV Type 1 vaccine. Journal of Veterinary Diagnostic Investigation 12: 263-265.
- Woodard, LF, D O'Toole, E Williams, and Van Campen, H. 2000. Flopper Syndrome Linked to Genetic Disease. Bovine Veterinarian, September, 2000, pg. 50-51.
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