Vaccination of the brushtail possum (Trichosurus vulpecula) against Mycobacterium bovis infection with bacille Calmette-Guérin: the response to multiple doses.

In New Zealand, the brushtail possum (Trichosurus vulpecula) is the principal wildlife vector of bovine tuberculosis. Control of infected possum populations contributes to the control of tuberculosis in domestic livestock. Vaccination is potentially a complementary strategy to population control, but to be cost-effective, administration of the vaccine to possums would need to be from an appropriately designed automatic vaccinator. Possums themselves would activate the vaccinator so that it would deliver an aerosol spray of vaccine. There would be no direct way to prevent possums receiving multiple doses of vaccine. This study examined the effect on protective immunity of repeated vaccination. Captive possums were vaccinated with BCG strain pasteur 1173P2 either 12 times at weekly intervals, twice at 6-weekly intervals, or once. Vaccination was by a combination of intranasal aerosol and conjunctival instillation. Eight weeks after the last dose of vaccine, all possums were challenged intratracheally with Mycobacterium bovis strain 83/6235. Vaccination induced a significant immune response as measured by the lymphocyte proliferation assay (LPA). A significant level of protection, as measured by the response to challenge, developed in all the vaccinated possum groups, but protection was greatest in the group vaccinated 12 times. It was concluded that protection would be enhanced if vaccinations were repeated at short intervals (weekly), but no benefit or detriment resulted from revaccination after longer intervals (1-2 months).     

Bovine sire effects on daughters' in vitro blood neutrophil functions, lymphocyte blastogenesis, serum complement and conglutinin levels

Blood neutrophil functions, lymphocyte blastogenic responses, serum complement, and serum conglutinin activity of 98 lactating Holstein cows from two genetic lines were evaluated. The genetic lines were produced in a selection experiment that created and perpetuated genetic differences in milk production for up to seven generations. No significant differences between the two genetic lines of cows were found for neutrophil function, lymphocyte blastogenic responses, serum complement levels, or serum conglutinin levels. Significant differences between sire progeny groups within lines were found for unstimulated and mitogen-stimulated lymphocyte blastogenesis (P less than 0.0001), and almost all neutrophil functions (antibody independent neutrophil cytotoxicity, antibody dependent neutrophil cytotoxicity, ingestion of bacteria, iodination, chemiluminescence, chemokinesis, and chemotaxis (P less than or equal to 0.05)). Sire progeny group differences (P less than or equal to 0.0001) within lines for serum complement and conglutinin activity were also found. Neutrophil chemiluminescence activity (positive relationship; P less than or equal to 0.001), concanavalin A-stimulated lymphocyte blastogenesis (positive relationship; P less than or equal to 0.004), and serum conglutinin activity levels (negative relationship; P less than or equal to 0.01) each had small but significant associations with the total milk somatic cell count. Cows seropositive for bovine leukosis virus had increased resting and mitogen-stimulated lymphocyte blastogenic activity and were associated with increased in vitro neutrophil random migration and production of superoxide anion. Estimates of genetic parameters of various immune cell functions, of serum complement and of conglutinin levels for daughters of 11 sires with 4-6 daughters in the data set were determined. In this report, genetic variation was demonstrated for nonspecific humoral and cellular immunity.     

Toxoplasmosis in Pallas' cats (Otocolobus felis manul) at the Denver Zoological Gardens.

In May 1996 the Denver Zoological Gardens obtained two male and two female Pallas' cats (Otocolobus felis manul) that were wild-caught in the Ukraine. These animals were part of a group of 16 wild-caught adults (eight male and eight female) imported to the United States and Canada between 1995 and 1996. The Denver Zoological Gardens cats were quarantined at the zoo hospital for approximately I mo. During the quarantine period they were immobilized for physical examination, and sera were obtained from them to evaluate for exposure to Toxoplasma gondii. All cats were positive for T. gondii antibodies by latex agglutination (titers from 1:512 to 1:1,024). After being paired for breeding, one pair produced two litters, and another pair produced four litters, a total of 17 kittens between 1997 and 2001. Four kittens and two young adults died from a disseminated granulomatous and necrotizing inflammation consistent with toxoplasmosis. Toxoplasma gondii infection was confirmed in all six deceased cats by polymerase chain reaction performed on formalin-fixed tissues. An additional five kittens disappeared and were not available for necropsy. The fatality rate from toxoplasmosis was 35.3% (6/17) for cats that were available for necropsy and could have been as high as 64.7% (11/17) if it were assumed that the disappeared kittens were also affected. The Pallas' kitten survival rate at the Denver Zoological Gardens was 35.3%. This article describes the clinical and pathologic features of toxoplasmosis in a group of Pallas' cats at the Denver Zoological Gardens.     

Bovine spongiform encephalopathy in Northern Ireland: epidemiological observations 1988-1990.

This study describes the epidemiological features of bovine spongiform encephalopathy (BSE) in Northern Ireland where the first case occurred in November 1988. They were very similar to those observed in Great Britain except that the annual incidence of BSE in 1990 in Northern Ireland, 2.3 confirmed cases per 10,000 adult cows, was approximately one 10th of that in Great Britain. The findings were also consistent with the current hypothesis that affected cattle had been exposed to a scrapie-like agent via cattle feedstuffs containing ruminant-derived protein. However, a preliminary investigation of the potential sources of infection for cattle in Northern Ireland did not provide any conclusive evidence.     

Evaluation of an enzyme-linked immunosorbent assay for diagnosis of trichinellosis in swine.

Experimental and field trials were conducted to evaluate an ELISA for its ability to detect Trichinella-infected domestic swine and to compare ELISA results with muscle-digestion test results. The ELISA used was a commercial double-antibody kit, containing an excretory-secretory antigen, and was evaluated principally for epidemiologic use. Experimentally induced infection in swine (4 groups of 3 pigs each; inoculated with 0, 50, 500 or 5,000 larvae) was detected as early as postinoculation week 4, with seroconversion of all inoculated swine by postinoculation week 8. The rate of seroconversion appeared to be affected by initial larval dose, time after inoculation, and immunocompetence of the individual host. Determination of antibody kinetics generally revealed rapidly increasing antibody titer, followed by its steady decrease in most pigs. Once seropositive, however, all pigs remained seropositive for the duration of the 10-week study. Presence of muscle larvae was confirmed in all infected pigs at termination of the study. We recognize that the experimental conditions may not be truly representative of those under which natural infection develops in pigs; however, the ELISA detected an infected pig with muscle larval density of 0.87 larvae/g of tissue. Results of a field trial (n = 310) indicated no muscle digestion test-positive pigs (35 g of diaphragm muscle digested/pig), but 3 samples tested positive by ELISA for specificity of 99.0%.     

Ruminal biohydrogenation of fatty acids from high-oleate sunflower seeds.

The objective of these experiments was to examine methods of modifying the fatty acid composition of bovine tissues. In the first experiment, four steers were fitted with duodenal fistulas and were assigned to four diets in a Latin square design. The steers were fed a control diet or the same diet containing 10% high-oleate partially crushed sunflower seeds, serum-coated sunflower seeds, and heat-treated, serum-coated sunflower seeds for 5 d. Samples of digesta and feces were collected on d 5. The inclusion of sunflower seeds (plain or serum-coated) in the diet increased (P less than .05) the digesta concentration of stearate. The percentage of stearate in the digesta and feces was increased (P less than .05) from 51 to 67% and from 64 to 74%, respectively, when steers were fed the untreated sunflower seed. The fecal concentration of oleate was increased (P less than .05) by dietary sunflower seeds in steers that were fed the serum-coated, unheated sunflower seeds. In a second experiment, heifers (four per group) were fed a corn-based control diet or diets containing 10% of high-oleate sunflower oil encapsulated with calcium alginate, either plain, coated with blood meal, or with blood meal integrated into the pellet. After 50 d on treatment, samples of perianal adipose tissue were obtained by biopsy. The fatty acid composition of the adipose tissue was not modified by the inclusion of the encapsulated oleate in the diet. In summary, limited ruminal bypass of sunflower seed oleate was accomplished with sunflower seed but not with encapsulated oleate.     

An unusual tumor of the nictitating membrane gland of dogs-- a case report]

A tumor of the third eyelid gland was diagnosed in a 13 year old female Chihuahua. Histopathology of the excised tissue revealed an apocrine adnexoma with squamous metaplasia. The literature regarding prolapse and tumors of the third eyelid gland was reviewed. No case with similar morphology to this tumor was described to our knowledge.     

A comparison between the nutritive value of short-cutting cycle, high temperature-dried alfalfa and timothy hay for horses.

The objective was to evaluate the nutritive value of short-cutting cycle, high temperature-dried (SCCHTD) alfalfa compared to timothy hay. This was achieved by carrying out 4 x 4 Latin Square digestibility trial using 4 Thoroughbred (one three-quarter Thoroughbred) horses (mean liveweight, 531 kg). The four dietary treatments were 0AA (timothy hay only), 33AA (0.33 alfalfa: 0.67 timothy hay), 67AA (0.67 alfalfa: 0.33 timothy hay) and 100AA (alfalfa only). Digestibility data were obtained by using acid-insoluble ash to estimate apparent digestibility coefficients of nutrients. Rate of passage of the feedstuff was determined using chromium-mordanted hay. Plasma triglyceride and cholesterol concentrations were estimated. The digestibilities of organic matter (0.63), energy (0.57) and crude protein (0.74) of the alfalfa were significantly (P less than 0.001) higher than those for the hay (0.45, 0.43 and 0.36 respectively). The fibre components of alfalfa and hay were digested to the same extent but the ether extract of alfalfa was less well digested. Alfalfa saponins had no consistently significant effects on plasma cholesterol and triglyceride values but may contribute to the negative digestibility of alfalfa ether extract. We conclude that SCCHTD alfalfa is of much higher nutritive value than timothy hay when fed to Thoroughbred horses.