Safety, efficacy, and immunogenicity of a modified-live equine influenza virus vaccine in ponies after induction of exercise-induced immunosuppression

OBJECTIVE: To determine safety, efficacy, and immunogenicity of an intranasal cold-adapted modified-live equine influenza virus vaccine administered to ponies following induction of exercise-induced immunosuppression. DESIGN: Prospective study. ANIMALS: Fifteen 9- to 15-month old ponies that had not had influenza. PROCEDURE: Five ponies were vaccinated after 5 days of strenuous exercise on a high-speed treadmill, 5 were vaccinated without undergoing exercise, and 5 were not vaccinated or exercised and served as controls. Three months later, all ponies were challenged by nebulization of homologous equine influenza virus. Clinical and hematologic responses and viral shedding were monitored, and serum and nasal secretions were collected for determination of influenza-virus-specific antibody isotype responses. RESULTS: Exercise caused immunosuppression, as indicated by depression of lymphocyte proliferation in response to pokeweed mitogen. Vaccination did not result in adverse clinical effects, and none of the vaccinated ponies developed clinical signs of infection following challenge exposure. In contrast, challenge exposure caused marked clinical signs of respiratory tract disease in 4 control ponies. Vaccinated and control ponies shed virus after challenge exposure. Antibody responses to vaccination were restricted to serum IgGa and IgGb responses in both vaccination groups. After challenge exposure, ponies in all groups generated serum IgGa and IgGb and nasal IgA responses. Patterns of serum hemagglutination inhibition titers were similar to patterns of IgGa and IgGb responses. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that administration of this MLV vaccine to ponies with exercise-induced immunosuppression was safe and that administration of a single dose to ponies provided clinical protection 3 months later.     

Radiodiagnostic examination of the swimbladder of some fish species

Radiodiagnostic methods have not been used previously for studying the anatomy and diseases of the swimbladder of freshwater fish species. In this study, the radiographic anatomy of the swimbladder and species-related differences in swimbladder structure were studied on plain radiographs taken of 12 Hungarian fish species of major economic importance. Changes observed by radiography were also studied by conventional parasitological methods. The radiodiagnostic method reported here appears to be a useful complement to diagnostic examinations that have been based merely on dissection so far. It enables evaluation of the pathological lesions in live condition, without causing damage to the fish.     

Interrelations of organism prevalence, specimen collection method, and host age, sex, and breed among 8,354 canine urinary tract infections (1969-1995)

Selected information was compiled from canine urinalyses and urine cultures conducted between January 1969 and December 1995. Eight thousand three hundred fifty-four microbial isolates (bacteria and fungi) included 4,873 isolates from females and 3,481 from males. Ten bacterial genera accounted for 96.3% of the urinary isolates, including Escherichia coli (44.1%), Staphylococcus spp. (11.6%), Proteus spp. (9.3%), Klebsiella spp. (9.1%), Enterococcus spp. (8.0%), and Streptococcus spp. (5.4%) as the 6 most common isolates in both genders of dogs. Among these 6 genera, female dogs were generally predisposed over males, although males had more urinary tract infections (UTIs) caused by Klebsiella spp. Distributions of ages at UTI diagnosis tended to be similar between genders. Infection with a single microbial species was responsible for >72% of UTIs in both genders. Among females, 40 breeds and a mixed-breed group represented 90.2% of all positive urine cultures, 88.4% of the individual dogs with UTIs. and 88.2% of the microbial isolations. Among males, these same 41 breed groups represented 87.9% of all positive urine cultures, 87.6% of the individual dogs, and 88.2% of the microbial isolations.     

Evaluation of highly sensitive indigenous milk ELISA kit with fecal culture, milk culture and fecal-PCR for the diagnosis of bovine Johne's disease (BJD) in India

Country lacks indigenous diagnostic kits against Johne's disease in animals. Indigenous ELISA and IS 900 PCR kits, originally developed for goats and sheep, have been adapted for screening of lactating cows. Multiple diagnostic tests were used to screen 26 lactating dairy cows against Johne's disease. Milk ELISA was evaluated with fecal culture, milk culture and fecal PCR. Of the 26 samples from lactating cows, 84.6, 96.1, 88.4 and 23.0% were positive in fecal culture, milk culture, m-ELISA and m-PCR, respectively. Comparatively milk sediment and milk fat culture detected 84.6 and 76.9% cows positive, respectively. Comparatively fecal culture and milk culture detected 84.6 and 96.1% cows positive, respectively. M-ELISA detected 11.5, 0.0, 11.5, 61.0 and 15.3%, cows as negative, suspected, low positive, positive and strong positive, respectively. There was good correlation between milk and fecal culture with m-ELISA. Three negative cows in m-ELISA were also detected in milk and fecal culture. Of the 26 decontaminated fecal samples, 23.0% cows were positive using specific IS 900 f-PCR. Comparative evaluation of m-ELISA with fecal and milk culture showed agreement in 80.7 and 84.6% cows, respectively. Sensitivity of m-ELISA with respect to fecal and culture was 90.9 and 95.6%, respectively. Comparative evaluation of four tests (milk culture, fecal culture, m-ELISA and f-PCR) showed that only 15.3% cows were detected in all the four tests. In three tests (fecal and milk culture and m-ELISA), 57.6% cows were detected positive. None of the cow was exclusively detected in f-PCR. Of the four diagnostic tests used milk culture was most sensitive (96.15%), followed by fecal culture (86.6%), m-ELISA (76.9%) and IS 900 PCR (23.0%) for the diagnosis of bovine Johne's disease (BJD). Milk ELISA detected only one cow extra, which was negative in milk culture. In view of the simplicity, rapidity and efficacy present milk ELISA kit employing soluble protoplasmic antigen from native Map 'Bison type' genotype of goat origin can be reliable for screening of bovine population against Johne's disease in India.     

Semen alterations in porcine rubulavirus-infected boars are related to viral excretion and have implications for artificial insemination

Porcine rubulavirus (PoRV), also known as blue eye disease (BED) of swine, causes respiratory and reproductive problems in pigs at several developmental stages. To study the effect of PoRV infection on semen production, five boars were infected with 1 x 10(6) TCID(50)/ml of PoRV strain PAC-3 and evaluated for 59 days post inoculation (DPI). Infected boars developed reproductive tract pathology that included swelling of the testes and epididymides. Analysis of the semen showed that the infection had little effect on semen production in four animals, but semen from one boar showed severe alterations in sperm concentration, motility, and morphology. When motility was analyzed in BTS-diluted semen after 24, 48, or 72 h, alterations were detected in all boars. Furthermore, viral antigen was detected in semen, the seminal plasma fraction, or sperm fraction from all boars. These results showed that PoRV is excreted via semen and, therefore, artificial insemination is a potential route of dissemination.     

Evaluation of polymerase chain reaction diagnosis of Cryptosporidium spp in dairy cattle and wildlife

This study investigated the utility of the polymerase chain reaction (PCR) protocol as a screening test for Cryptosporidium spp in 125 fecal samples from dairy cattle and wild rodents. Samples initially examined by fecal flotation and ELISA were evaluated using four PCR protocols (18S SSU rRNA, TRAP-C2, HSP70, and COWP), and the relative accuracy and agreement of PCR protocols was assessed. Although PCR can be both highly sensitive and accurate, the ability of these protocols to accurately detect DNA in samples can vary. A combination of techniques may be the best choice for to screen samples for this parasite.     

Diagnostic validity and costs of pooled fecal samples and individual blood or fecal samples to determine the cow- and herd-status for Mycobacterium avium subsp. paratuberculosis

Two tests are used on a regular basis to detect Mycobacterium avium subsp. paratuberculosis (Map): ELISA and fecal culture. Fecal culture is considered more sensitive and specific but is costly and requires 3-4 months for results. Pooling of fecal samples of individual animals may reduce the high costs of fecal culture. The objective of the study was to investigate the diagnostic validity and costs for pooling of fecal samples in dairy farms relative to culture or an ELISA on individual samples to determine the cow- or herd-status for Map. Fifty fecal and blood samples per herd were collected in 12 Chilean dairy herds. The sensitivity of pooling was estimated given the pool-size, amount of shedding in the pool and the prevalence in the herd. The sensitivity of the pools relative to individual fecal culture was 46% (95% CI 29-63%) and 48% (28-68%) for pools of 5 and 10 cows, respectively. The sensitivity of the pools was lower in pools with low shedders (26 and 24% for pools of 5 and 10, respectively) than in pools with moderate or heavy shedders (>75% sensitivity). Pools of 10 cows are the better option to determine or monitor the herd status. A whole-herd ELISA is the least expensive way to determine the status of individual cows but has a lower Se and Sp than individual culture.     

Calf-level risk factors for neonatal diarrhea and shedding of Cryptosporidium parvum in Ontario dairy calves

This work was conducted to investigate calf-level factors that influence the risk of neonatal diarrhea and shedding of Cryptosporidium parvum oocysts in calves, on dairy farms in Ontario with histories of calf diarrhea or cryptosporidiosis. Fecal samples were collected weekly for 4 weeks from each of 1045 calves under 30 days of age on 11 dairy farms in south-western Ontario during the summer of 2003 and the winter of 2004. A questionnaire designed to gather information on calf-level management factors was administered on farm for each calf in the study. Samples were examined for C. parvum oocysts by microscopy, and a subset of specimens was also tested for enterotoxigenic Escherichia coli, Salmonella, bovine rotavirus and bovine coronavirus. The consistency of each sample was scored and recorded at the time of collection in order to assess the presence or absence of diarrhea. In addition, a blood sample was taken from each calf upon enrollment in the study, for assessment of maternal antibody transfer and for polymerase chain reaction testing for persistent bovine viral diarrhea virus infection. Using the GLLAMM function in Stata 9.0, multilevel regression techniques were employed to investigate associations between management practices and the risk of C. parvum shedding or diarrhea. C. parvum oocysts were detected in the feces of 78% of the 919 calves from which all four fecal samples had been collected. Furthermore, 73% of the 846 calves for which all four fecal consistency scores had been recorded were diarrheic at the time of collection of at least one sample. Significant predictors of the calf-level risk of C. parvum shedding included the use of calf diarrhea prophylaxis in pregnant cows, and the type of maternity facilities in which the calves were born. Factors associated with an increased risk of diarrhea were leaving the calf with the dam for more than an hour after birth, and the birth of a calf in the summer as opposed to winter. Calves shedding C. parvum oocysts had 5.3 (95% CI 4.4, 6.4) times the odds of diarrhea than non-shedding calves, controlling for other factors included in the final multivariable model. Furthermore, infected calves shedding more than 2.2 x 10(5) oocysts per gram of feces were more likely to scour than infected calves shedding lower numbers of oocysts (OR= 6.1, 95% CI 4.8, 7.8). The odds of diarrhea in calves shedding oocysts that had been allowed to remain with their dams for more than an hour were higher than the odds of diarrhea in shedding calves that had been separated from their dams within an hour after birth.