CONGENITAL BOVINE EPIZOOTIC ARTHROGRYPOSIS AND HYDRANENCEPHALY

SUMMARY Epizootics of congenital neurological defects in calves have been recorded at various intervals in south eastern New South Wales for over 40 years. In 1974 a particularly severe outbreak occurred. Field observations of the clinical entities, their time of appearance, distribution and incidence were recorded in an attempt to determine an epidemiological pattern. The neurological entities observed occupied different time spans in the opizootic, the order of appearance being polioencephalomyelltis, arthrogryposis, hydranencephaly and micrencephaly. The probable period of infection correlated well with the likely presence of Culiciodes brevitarsus in the epizootic area and the distribution and incidence of neurologic cases likewise correlated well with the expected geographical and climatic distribution of C. brevitarsus in this period. The probable association of Akabane virus infection and the outbreak of stillbirths and abortions which preceded the neurologic entities is discussed.     

荧光定量PCR方法的原理及其在研究病毒在动物体内分布规律的应用

研究病毒在动物体内的分布情况,主要是为了掌握病毒在动物体内的生长繁殖规律,找到病毒的靶细胞和靶器官,为进一步研究其致病机理和防制技术提供试验依据。荧光定量PCR法具有定量准确、特异性强、自动化程度高等特点,是研究病毒分布规律的主要方法之一,作者综述了此方法的原理及应用。     

The diagnosis and treatment of periorbital sarcoid in the horse: 445 cases from 1974 to 1999

OBJECTIVE: Diagnosis and management of periorbital sarcoids in horses is a significant clinical challenge for the practicing veterinary surgeon and pathologist. The purpose of this study was to investigate the response of various types of sarcoids to different therapeutic methods. Animals studied Medical records of 445 clinical patients. Procedures This paper retrospectively examines the clinical and histological features of periorbital sarcoids and the treatment of 445 cases. Treatment by surgical excision, cryosurgery, Bacillus-Calmette-Gaérin (BCG) immunomodulation, topical cytotoxic applications, and radiation are described. RESULTS: Six types of sarcoid can be found in the immediate periorbital region and each has some characteristics of other disorders of the skin with which they can be confused. The diagnosis of sarcoids is, however, relatively simple in most cases. The lesions are not necessarily restricted to the dermis and epidermis, but commonly invade into the subcutis and the deeper muscular structures around the eye. Treatment with radiation is expensive and difficult to manage but resulted in the best outcome with almost 100% resolution in 66 cases. By contrast, surgical excision has serious potential complications that arise primarily as a result of the infiltrative nature of periorbital sarcoids. The value of BCG immunomodulation therapy for fibroblastic and nodular lesions described by previous workers is confirmed in this paper, with a good overall response (69%), provided that the material was injected intralesionally. Perilesional injection did not appear to carry a significant benefit. However, treatment of verrucose or occult lesions by this method gave generally poor results. The results of intralesional injection of cisplatin emulsions suggest that this may be an effective method of treatment in cases where other modalities are not feasible. In common with previous reports, failure to resolve the lesions frequently resulted in regrowth of the tumor, and in most cases this recurrence appeared to be more aggressive, with extensive local infiltration and faster growth. Conclusion The periorbital tissues are less tolerant of damage than those at many other sites and therefore certain treatment methods may be contraindicated. This suggests that it is important to select the best possible treatment at the first opportunity. It is a wise precaution to warn owners of horses with periorbital sarcoids of the dangers of leaving them and the particular risks associated with the currently available treatments.     

Trends in hip dysplasia control: analysis of radiographs submitted to the Orthopedic Foundation for Animals, 1974 to 1984

From 1974 through 1984, the Orthopedic Foundation for Animals evaluated 143,218 radiographic submissions representing 151 breeds of dogs. All breeds from which there were 35 or more evaluations had some frequency of dysplasia. Seventy breeds, each with over 100 submissions, were tabulated and ranked according to frequency of hip dysplasia. Frequency of dysplasia varied from 0.6% in the Borzoi to 46.9% in the Saint Bernard. These data were compared with data obtained earlier (1966 to 1973) on evaluations in 38 breeds for changes in frequency. There was significant (P less than 0.05) reduction in frequency of dysplasia in 27 breeds, a significant (P less than 0.05) increase in frequency in only 1 breed (German Shorthaired Pointer), and no significant change in frequency in 10 breeds. The median significant decrease was 22.4%, and the range was from 3.1% in the Chesapeake Bay Retriever to 48.7% in the Keeshond. The reduction in frequency of hip dysplasia demonstrated the value of a control program. There were 5 breeds with a significant (P less than 0.05) decrease in frequency of dysplasia that had over 5,000 evaluations from 1974 to 1984. The decreases in frequency were independent of changes in American Kennel Club registrations for these breeds (a dramatic decline in registrations for the German Shepherd Dog and Old English Sheepdog, and a dramatic increase for the Rottweiler, Golden Retriever, and Labrador Retriever). Frequency regressed linearly in the German Shepherd Dog and Old English Sheepdog, but regressed nonlinearly in the other 3 breeds. The percentage reduction in frequency from the base frequency (1966 to 1973) for these breeds was 17.5% for the German Shepherd Dog, 23.1% for the Old English Sheepdog, 9.1% for the Rottweiler, 10.1% for the Golden Retriever, and 6.8% for the Labrador Retriever.     

Bovine Vibriosis: The Distribution and Specificity of Antibodies Induced by Vaccination and Infection and the Immunofluorescent Localization of the Organism in infected Heifers

Two groups of three Holstein heifers were immunized respectively with Vibrio fetus venerealis and Vibrio fetus intestinalis incorporated in Freund's complete adjuvant. Both serum and vaginal mucus agglutination titers increased following immunization. Vaginal mucus samples were more frequently positive when the homologous cells were used as antigen in the agglutination test.

Ten non-immunized heifers were inoculated with another strain of V. fetus venerealis and slaughtered at periods of 30 to 40 and 60 to 70 days post-inoculation (DPI). Agglutinating antibodies were present in the vaginal mucus of some infected individuals by five weeks post-inoculation. In the course of the experiment 11 vaginal mucus samples were obtained which agglutinated heated cells of the infecting strain; one aggglutinated whole cells. Precipitins toward homologous antigens could not be demonstrated in vaginal mucus but four of six samples tested precipitated a heat stable extract from an intestinal strain of the same O-serotype. Bacterial antigen was detected by immunofluorescence on the surface, as well as within and beneath the epithelium at all levels of the reproductive tract regardless of time of slaughter. Lesions in infected animals consisted of focal and diffuse lymphocytosis, plasmacytosis, and epithelial vacuolation. Diffuse neutrophilic infiltration of the oviducts was observed.

Agglutinins appeared in the serum of each of nine heifers immunized with whole cells of same venereal strain. Group mean serum titers for whole and heated cells were 1/28,000 and 1/1,300 respectively. Vaginal mucus samples agglutinated whole cells in 48% of tests while 6.3% reacted with heated cells. Serum, but not vaginal mucus, of immunized animals precipitated soluble antigens of the immunizing strain. The immunizing strain of V. fetus did not infect the reproductive tract of any of six immunized heifers upon challenge.

     

Antibodies to bovine serum albumin in swine sera: implications for false-positive reactions in the serodiagnosis of African swine fever

Antibodies to bovine serum albumin were detected in swine sera by use of an immunoblotting technique. Such sera had false-positive reactions, as determined by results of African swine fever virus serodiagnostic techniques when bovine serum albumin was a contaminant in the soluble cytoplasmic antigen obtained from infected cells cultured in the presence of bovine serum. The soluble cytoplasmic antigen obtained from cell cultures infected with African swine fever virus in the presence of porcine serum did not react with the false-positive sera and, therefore, was used for African swine fever virus serodiagnostic methods, with 0% false-positive results.     

Vaccination Response of Young Foals to Keyhole Limpet Hemocyanin: Evidence of Effective Priming in the Presence of Maternal Antibodies

The ability to produce antibodies is essential for protection from infectious disease; however, in the neonate, maternal antibodies have been proposed to interfere with the foal's ability to respond to vaccination. In species other than the equid, keyhole limpet hemocyanin, a high-molecular weight protein, is used in vivo as an experimental vaccine component because of its high intrinsic immunogenicity. In this study, we show that young foals are able to produce a primary antibody response to vaccination at an early age. Thus, foals, like human infants, are capable of responding to antigenic exposure to a novel antigen (keyhole limpet hemocyanin) during the neonatal period. Although vaccinating foals in the presence of maternal antibodies failed to induce a primary serological response, priming occurred as comparable anamnestic responses were detected upon subsequent exposure to the antigen. There was no evidence of tolerance induction.     

Epizootiology of Mink Enteritis: I. Stability of the Virus in Feces Exposed to Natural Environmental Factors

MEV infective feces, half-buried in the ground for 9 months, (from November to July), contained infectious virus when inoculated into susceptible hosts. It is believed that MEV in feces, if protected by favorable environmental conditions, is capable of infecting mink for an indefinite period beyond nine months.     

Distribution of enrofloxacin and its active metabolite, using an in vivo ultrafiltration sampling technique after the injection of enrofloxacin to pigs

The objective of this study was to determine the pharmacokinetics (PK) of enrofloxacin in pigs and compare to the tissue interstitial fluid (ISF). Six healthy, young pigs were administered 7.5 mg/kg enrofloxacin subcutaneously (SC). Blood and ISF samples were collected from preplaced intravenous catheters and ultrafiltration sampling probes placed in three different tissue sites (intramuscular, subcutaneous, and intrapleural). Enrofloxacin concentrations were measured using high-pressure liquid chromatography with fluorescence detection, PK parameters were analyzed using a one-compartment model, and protein binding was determined using a microcentrifugation system. Concentrations of the active metabolite ciprofloxacin were negligible. The mean ± SD enrofloxacin plasma half-life, volume of distribution, clearance, and peak concentration were 26.6 ± 6.2 h (harmonic mean), 6.4 ± 1.2 L/kg, 0.18 ± 0.08 L/kg/h, and 1.1 ± 0.3 μg/mL, respectively. The half-life of enrofloxacin from the tissues was 23.6 h, and the maximum concentration was 1.26 μg/mL. Tissue penetration, as measured by a ratio of area-under-the-curve (AUC), was 139% (± 69%). Plasma protein binding was 31.1% and 37.13% for high and low concentrations, respectively. This study demonstrated that the concentration of biologically active enrofloxacin in tissues exceeds the concentration predicted by the unbound fraction of enrofloxacin in pig plasma. At a dose of 7.5 mg/kg SC, the high tissue concentrations and long half-life produce an AUC/MIC ratio sufficient for the pathogens that cause respiratory infections in pigs.