Clinical and pathological studies on intoxication in horses from freshly cut Jimson weed (Datura stramonium)-contaminated maize intended for ensiling

Spontaneous intoxication in 34 horses after ingesting freshly harvested maize that was to be used for ensiling and heavily contaminated with young Datura stramonium plants, is described. The clinical status of all horses was monitored for 7 days, and included body (rectal) temperature, respiratory and heart rates, colour and moistness of visible mucosae, changes in pupil size, appetite, thirst, general behaviour, locomotion, sensory perceptions, urination and defaecation. The intoxication was accompanied by altered clinical status, namely mild hyperthermia, tachycardia, polypnoea, dyspnoea and shallow breathing, mydriasis, dry oral, rectal, vaginal and nasal mucosae, acute gastric dilatation and severe intestinal gas accumulation, anorexia to complete refusal of feed, decreased or absent thirst, absence of defaecation and urination. As a result of the treatment, the clinical parameters normalised between days 2 and 5. Necropsies and pathological studies were performed on two horses that died, revealing toxic liver dystrophy, cardiac lesions and substantial dystrophic and necrotic processes in the kidneys. The observed clinical signs, the pathomorphological changes and the applied therapy could be used in the diagnosis, differential diagnosis, prognosis and treatment of Jimson weed intoxication.     

Bluetongue in The Netherlands; description of the first clinical cases and differential diagnosis. Common symptoms just a little different and in too many herds

For the first time Bluetongue (BT) has been diagnosed in the Netherlands. The clinical symptoms of BT on five farms during the first outbreak ever in the Netherlands are described. Fever and swollen sensitive coronets leading to reluctance to stand and walk were sometimes the first symptoms. Later lesions in the mouth occurred with foamy salivation and respiratory problems. In other cases a swollen head with swollen lips and foamy salivation were the first clinical signs. Also sudden death occurred. In the first sixteen confirmed cases morbidity and mortality were lower than described in outbreaks in other countries. Good collaboration between practitioners, specialists of the Animal Health Service (GD-Deventer), and specialists of the Food and Consumer Product Safety Authority (VWA) and CIDC-Lelystad (Wageningen UR) led to a rapid notification and ultimately confirmation of the suspected diagnosis BT.     

Effects of boar presence on agonistic behavior, shoulder scratches, and stress response of bred sows at mixing

The objective of this study was to determine the effects of boar presence on aggression, shoulder scratches, and salivary cortisol in group-housed sows during the period after mixing, which is when dominance hierarchies are formed. A total of 225 York-shire sows were used. Five groups of 15 sows were each exposed to 1 of 3 levels of boar presence (n = 15): physical (boar in pen with sows; 2.15 m2 per sow), fenceline (boar housed adjacent to sows; 2.3 m2 per sow), or control (no boar in the room; 2.3 m2 per sow). The experiment was divided into 2 phases. In phase 1, behavioral measurements were taken for 48 h after mixing and boar introduction. In phase 2, behavioral measurements were taken beginning on d 6 after mixing and included 24 h before and 48 h after boar removal. In phases 1 and 2, shoulder scratches were scored 24 h before and 24 h after mixing and boar removal, respectively. Saliva samples were collected each morning (0600 to 0700) and afternoon (1600 to 1700) during both phases. Frequencies of intersow aggressive contact (bite, body knock, and head knock) and threats as well as frequencies and durations of fighting bouts were determined from video recordings during daily feeding (49.6 +/- 1.4 min) and nonfeeding (21 +/- 0.2 h) periods. During phase 1, boar presence did not affect the frequency of threats during either the feeding or nonfeeding periods. Control groups had fewer aggressive contacts at feeding during the 25- to 48-h period compared with the fenceline groups (P = 0.01). Total duration of fighting and average fighting bout duration were unaffected by treatment. However, the number of fights occurring during feeding 25 to 48 h postmixing was lower in the physical groups than in the fenceline groups (P = 0.023); measures for the control groups were intermediate. Physical sows also received fewer shoulder scratches postmixing than did control sows (P = 0.048). After mixing, physical sows showed greater morning (P = 0.08) and afternoon (6 h postmixing, P = 0.01; 32 h postmixing, P = 0.08) salivary cortisol concentrations compared with fenceline sows, although they were only numerically greater than those for control sows. During phase 2, removing the boar did not increase fighting among sows or affect shoulder scratches or salivary cortisol concentrations. The presence of a boar was minimally effective at reducing fighting and scratches during the postmixing period, and sows showed a greater stress response in the presence of a boar.     

Hemorrhagic enteritis in turkeys: purification and quantification of the virus

Two methods for purifying the virus of hemorrhagic enteritis from infected turkey spleens are described. One procedure utilized precipitation with polyethylene glycol, and the other consisted of trichlorotrifluoroethane extraction. Both procedures included sucrose-cesium chloride gradient centrifugation in the final purification step. The buoyant density of the viral fraction was 1.34 g/cm3, typical for adenoviral particles, and the size and morphologic characteristics of the virions observed by transmission electron microscopy suggested that the purified virus belongs to the family Adenoviridae. The biologic activity of the purified virus was titrated by inoculating 10-fold dilutions of the viral suspension into turkey poults. Mortality and hemorrhagic diarrhea proved to be inconsistent parameters of infection, and the degree of splenomegaly was proportional to the virus dose. The body/spleen ratio was the parameter selected for measuring viral activity, and the body/spleen ratio 50% was adopted as the unit for the titration of the virus. By using the same system it was demonstrated that the infectivity of the virus could be neutralized with antiserum produced in turkeys.     

Blood pressure response to phenylephrine infusion in halothane-anesthetized dogs given acetylpromazine maleate

To quantitate acetylpromazine-induced alpha-adrenergic receptor blockade, phenylephrine was infused into dogs. The amount of phenylephrine necessary to increase the mean arterial blood pressure (MAP) 50% above base line, with or without the prior administration of acetylpromazine, served to quantify the degree of acetylpromazine-induced alpha-adrenergic receptor blockade. Seven dogs were anesthetized with thiopental, maintained on halothane in oxygen, and mechanically ventilated. All infusions were made through a catheter in the cephalic vein. Continuous recordings were made of MAP and a lead II ECG. After induction of anesthesia, instrumentation, and stabilization of heart rate, MAP, and ventilation, 6 group I dogs were infused with phenylephrine until a 50% increase in MAP was recorded (phenylephrine control). On subsequent research days, each dog was anesthetized, instrumented as described, and given (IV) 1 of 3 dosages of acetylpromazine in the following order--0.05, 0.125, and 0.25 mg/kg. The dose of phenylephrine necessary to increase MAP 50% in the presence of acetylpromazine was recorded. Five group II dogs were studied as in group I, but each dog was given (IM) atropine (0.04 mg/kg) before anesthetization. Two dosages of acetylpromazine were studied in the following order--0.05 and 0.25 mg/kg. Group I dogs, when compared with their phenylephrine controls, were given significantly more phenylephrine to raise MAP 50% at each dose of acetylpromazine studied. The same trend was observed in group II dogs, but at smaller doses of phenylephrine, probably as a result of the positive chronotropic effect of atropine on the heart.     

Esophagotomy in the pony: comparison of surgical techniques and form of feed

Esophageal healing was studied in 12 ponies after cervical esophagotomy. The esophagus was sutured, feed and water were withheld for 48 hours, and then all ponies were permitted to eat. In group I (n = 6), a longitudinal esophagotomy was made. In group II (n = 6), a rotational esophagotomy was made with the mucosal incision 180 degrees away from the incision in the esophageal muscle. Three ponies in each group were fed a soft diet ad libitum for 9 days, and then were allowed access to hay and grain. The remaining ponies were fed hay and grain. The esophagotomies of all hay-fed ponies dehisced and healed by second intention, whereas esophagotomies healed by first intention in the ponies given a soft diet. Endoscopic and radiographic examinations indicated that the progression of healing in the present study was a function of diet (form of food), rather than surgical technique. The cross-sectional width of the muscularis externa at the incision site was 39.6% greater in mash-fed ponies than in hay-fed ponies. Based on density-dependent image analysis, average elastin content and reticulin fiber of the submucosa and muscularis externa at the incision were not influenced by the form of feed or surgical technique, although elastin fiber regeneration did not occur at the site of the incision.     

Erythrocyte macrocytosis in feline leukemia virus associated anemia

Using erythrocyte volume distribution histograms (erythrograms), erythrocyte macrocytosis and anisocytosis were quantitated in 139 cats tested for feline leukemia virus group-specific antigen. Feline leukemia virus-negative cats with non-regenerative anemia or normal packed cell volumes had normal mean corpuscular volume values. Uninfected cats with regenerative anemia had prominent significantly increased macrocytosis and anisocytosis (p less than 0.01). Ninety percent of 62 feline leukemia virus-positive cats had altered erythrograms. Thirty-three feline leukemia virus-positive cats with non-regenerative anemia had marked macrocytosis. Their mean corpuscular volume values (mean 60 fl +/- 2 fl standard error, reference range of 37-49 fl) were significantly greater than those of feline leukemia virus-negative cats except for those with regenerative anemia. Feline leukemia virus-positive, non-anemic cats had significantly increased mean corpuscular volume values of intermediate magnitude. Nine adult cats experimentally infected with feline leukemia virus developed non-regenerative anemia with significant increases in mean corpuscular volume and anisocytosis. However, the macrocytosis observed in these cats was considerably less than in naturally occurring feline leukemia virus-positive cats with non-regenerative anemia. These observations indicate there are events in the pathogenesis of feline leukemia virus-associated anemia other than simple erythroid hypoplasia. We suggest that hemolysis and erythrocyte regeneration occur before erythroid hypoplasia and may partially account for macrocytosis observed in the face of non-regenerative anemia.     

Fine structure and invasive behaviour of the early developmental stages of Theileria annulata in vitro

The interaction, in vitro, between bovine peripheral blood lymphocytes and sporozoites of Theileria annulata (Ankara) was studied by light and electron microscopy. Beginning five minutes following incubation, samples were taken for Giemsa-stained smears and glutaraldehyde-fixed pellets, for light and electron microscopy, respectively. Sporozoites of T. annulata measure an average of 0.9 microns long, 0.8 microns broad and possess a limiting unit membrane, the pellicle; a round-to-ovoid, eccentrically situated, non-chromocentric nucleus; double-membraned, tubular, acristate mitochondria; varying numbers of anisocytic, densely osmiophilic and pleomorphic organelles, the rhoptries which together with the polar ring form the apical complex; and numerous, loosely scattered, electron-dense ribosomal particles. As early as 5 min of incubation, sporozoites had made contact with, and penetrated, lymphocytes. Sporozoites consistently attached to the lymphocyte plasmalemma by their basal end, possibly at specific receptor sites. Apparently only a proportion of lymphocytes (up to 40% and more commonly 10-20%) were susceptible. Two subpopulations of the susceptible lymphocytes were observed; one which appeared to have receptor sites localized on one pole of the plasmalemma and the other subpopulation in which the receptor sites were distributed evenly around the plasmalemmal surface. Within individual susceptible lymphocytes, the number of interiorized sporozoites increased from 1 to 3 at 5-10 min to as many as 15 or more parasites at around 60 min of incubation. Theileria annulata sporozoites were interiorized by the invagination of the host cell plasmalemma which remained intact throughout the process but later fragmented. Within 30 min of interiorization, each sporozoite underwent dedifferentiation by the loss of its rhoptries and transformed into a trophozoite. Around 24 h, the trophozoite, a uninucleate, motile and feeding stage of the parasite, developed into a schizont by an acentric, closed mitosis.     

Feline miliary eczema: megestrol acetate does not suppress immune responses

Megestrol acetate was found to have no influence on immunological skin and corneal reactivity nor on antibody responses in guinea pigs. Its curative effect in feline miliary eczema is probably not, therefore, the result of interference with the immune response.