Diagnostic characterization of a feral swine herd enzootically infected with Brucella.

Eighty feral swine were trapped from a herd that had been documented to be seropositive for Brucella and which had been used for Brucella abortus RB51 vaccine trials on a 7,100-hectare tract of land in South Carolina. The animals were euthanized and complete necropsies were performed. Samples were taken for histopathology, Brucella culture, and Brucella serology. Brucella was cultured from 62 (77.5%) animals. Brucella suis was isolated from 55 animals (68.8%), and all isolates were biovar 1. Brucella abortus was isolated from 28 animals (35.0%), and isolates included field strain biovar 1 (21 animals; 26.3%), vaccine strain Brucella abortus S19 (8 animals, 10.0%), and vaccine strain Brucella abortus RB51 (6 animals, 7.5%). Males were significantly more likely to be culture positive than females (92.9% vs. 60.6%). Thirty-nine animals (48.8%) were seropositive. Males also had a significantly higher seropositivity rate than females (61.9% vs. 34.2%). The relative sensitivity rates were significantly higher for the standard tube test (44.6%) and fluorescence polarization assay (42.6%) than the card agglutination test (13.1%). Lesions consistent with Brucella infection were commonly found in the animals surveyed and included inflammatory lesions of the lymph nodes, liver, kidney, and male reproductive organs, which ranged from lymphoplasmacytic to pyogranulomatous with necrosis. This is the first report of an apparent enzootic Brucella abortus infection in a feral swine herd suggesting that feral swine may serve as a reservoir of infection for Brucella abortus as well as Brucella suis for domestic livestock.     

An improved fluorimetric determination of alpha-mannosidase activity in bovine plasma.

This paper describes a manual fluorimetric method for the assay of acidic alpha-mannosidase activity in bovine plasma. The optimum conditions for the assay of this enzyme were studied. The assay method devised includes the addition of zinc to the substrate, which stimulates activity by approximately twofold, and reduces the optimum substrate concentration. This latter feature affords considerable cost saving in each test. We have also shown that the alpha-mannosidase activity in lithium heparin plasma, EDTA plasma and blood serum is the same whether the plasma/serum is separated from the cells/clot at 6, 20 or 25 hours after sample collection. This has eliminated the previous necessity of having to deliver whole blood samples to the laboratory within 6 hours of collection. Furthermore samples for the supplementary neutrophil assay can now be taken at the same time as those for the plasma test, and both samples forwarded together. The plasma alpha-mannosidase assay is a rapid and reliable screening test for the mannosidosis genotype and for detecting carrier animals. Carrying out this plasma assay in conjunction with the more definitive neutrophil assay provides a reliable method of distinguishing homozygotes and heterozygotes from normal animals.     

Capillary permeability to endogenous macromolecules in the equine digit

Microvascular permeability characteristics were evaluated in digits of 7 adult horses. After capillaries were isolated and an extracorporeal perfusion circuit for the digit was established, a lymphatic vessel draining the distal portion of the phalangeal region was cannulated at the level of the coronary band. Venous pressure was increased in a stepwise manner, and lymph flow, lymph protein concentration (Cl), and plasma protein concentration (Cp) were determined after measured variables were allowed to reach steady state. Lymph-to-plasma protein concentration ratios (Cl/Cp) and lymph and plasma oncotic pressures were determined from samples collected during steady state. The osmotic reflection coefficient was determined after Cl/Cp became constant, regardless of increasing lymph flow, and was expressed as 1--Cl/Cp. The osmotic reflection coefficient for the digit was 0.67. Seemingly, the microvasculature bed of the digit was relatively permeable and could maintain only 67% of the endogenous macromolecules within the vasculature.     

Evaluation of acepromazine/meperidine/atropine premedication followed by thiopental anesthesia in the cat.

Cardiopulmonary function was assessed in healthy cats premedicated with intramuscular acepromazine, meperidine, atropine combination (premix), followed by induction and maintenance with intravenous thiopental for 30 min. Cardiac output by thermodilution, heart rate, blood pressure and blood gas analysis were evaluated over 120 min. A minor degree of respiratory depression was noted in the cats. Cardiac index (cardiac output/kg) was significantly depressed following thiopental induction and for the entire 120 min studied. Stroke volume was significantly reduced after premix administration and for 90 min posthiopental induction. No significant change in heart rate, systemic vascular resistance or blood pressure was observed. Significant cardiovascular depression was produced by the premedicant, and this persisted following thiopental anesthesia.     

The effect of certain topical medications on healing of cutaneous wounds in the common garter snake (Thamnophis sirtalis).

The effects of four topical medications on the rate and character of healing of cutaneous wounds were studied in six common garter snakes (Thamnophis sirtalis) held at an ambient temperature of 30 degrees C. Two sets of five 6 to 8 mm round excisional wounds, four test and one control site in each set, were created on the dorsolateral body wall of each snake. Wounds were examined daily and treated for ten days, then the snakes were killed and sections of all wounds were examined by light microscopy. Composite scores, derived by ranking each treatment group in relation to the control group (control score = 0) for each of 22 characteristics associated with wound healing, were used to compare the overall effects of each treatment. Statistical comparisons were made between groups for 20 characteristics. Wounds treated with a polyurethane film merited a score of +12 and had significantly more advanced healing than untreated controls for three characteristics. Wounds treated with an ointment containing scarlet red scored +6 but healing was not significantly greater than controls. Wounds treated with an antibacterial spray powder and an antibacterial ointment healed more slowly than controls and had scores of -6 and -12 respectively.     

Uterine Infection Influences Size and Follicular Fluid Composition of the Largest Follicle in Buffalo (Bubalus bubalis)

The effect of uterine infection on size and follicular fluid composition of the largest follicle was studied in buffalo. Reproductive tracts were collected from 102 graded Murrah buffaloes at an abattoir. Uterine infection was diagnosed by physical examination of uterine mucus, white side test and uterine cytology. Samples with pus‐containing mucus, positive reaction on white side test and/or >5% neutrophils were considered to be positive for uterine infection. Diameter of the largest follicle was measured, and follicular fluid was aspirated and assayed for nitric oxide (NO), ascorbic acid (AA), cholesterol, oestradiol (E₂) and progesterone (P₄). Infected buffaloes had smaller‐sized (p < 0.0001) largest follicles than non‐infected buffaloes. Follicular fluid collected from the largest follicle in infected buffaloes had greater (p < 0.0001) NO and P₄ concentrations coincident with lesser AA (p < 0.001), cholesterol (p < 0.0001) and E₂ (p < 0.0001) concentrations. Results indicated that uterine infection has an inhibitory effect on growth of the largest follicle in buffalo. The changes in follicular fluid composition in infected buffaloes suggest that the direct effect of uterine infection on ovarian function may be mediated through an alteration in the follicular microenvironment. Greater NO and lesser AA concentrations in the follicular fluid of infected animals are novel findings.     

A case-control study of the congenital hypothyroidism and dysmaturity syndrome of foals.

A case-control study was conducted to identify risk factors for the congenital hypothyroidism and dysmaturity syndrome of foals. A questionnaire was used during personal interviews of foal owners and farm managers to collect information on animal signalment, farm environment, and mare management. Information on 39 foals with the congenital hypothyroidism and dysmaturity syndrome were compared with 39 control foals. Foals with the syndrome had a significantly (P < 0.0001) longer gestation (357.6 d) than control foals (338.9 d). Pregnant mares that were fed greenfeed, did not receive any supplemental mineral, left their "home farm" during gestation, or grazed irrigated pasture had 13.1 (P = 0.0068), 5.6 (P = 0.0472), 4.3 (P = 0.0076), and approximately 15.3 (P = 0.0245), respectively, greater odds of producing an affected foal than mares not experiencing these events. Greenfeed often contains high levels of nitrate (NO3-), which is known to impair thyroid gland function. In light of this, forage samples from participating farms were analyzed for nitrate levels. The odds of one or more congenitally hypothyroid and dysmature foals being born on a farm feeding forage with at least a trace of nitrate was 8.0 times greater (P = 0.0873) than the odds of the disease occurring on a farm that fed forage free of nitrate. Further, the odds of a mare producing an affected foal when fed forage containing at least a trace of nitrate were 5.9 times greater (P = 0.0007) than those of a mare fed nitrate free forage. This study suggests that congenital hypothyroidism and dysmaturity syndrome in foals may be the result of diets that contain nitrate or that are low in iodine being fed to pregnant mares.