A protective antigen for Turkeys purified from a type 1 strain of Pasteurella multocida

A protective antigen was purified from a saline extract of a Type 1 strain of Pasteurella multocida by chromatographic methods, and its chemical and immunological ccharacteristics were studied. Three protein peaks were obtained from crude extract by gel filtration with Sephadex G-200. A bacteria-specific antigen was detected only in the first peak fraction, which, after passing through an immunoadsorbent column to remove any components originating from the growth medium, was adsorbed onto DEAE-cellulose followed by elution with a gradient of NaCl. From the first peak fraction of the gel filtration, 4 protein peaks were obtained, the second and third peaks being the major ones. Carbohydrate/protein ratios of the peak fractions varied from 0.06 to 1.0. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that 2 proteins of molecular weights 44 000 and 25 000 were present in all the fractions. The 4 DEAE-cellulose fractions (DP-1 to DP-4) contained a single antigenically identical material, and induced protective immunity in turkeys against challenge exposure. The second peak fraction from DEAE-cellulose (DP-2) protected turkeys when subcutaneously injected as 2 doses of 10 μg protein with a 14-day interval between doses. The DP-2 fraction induced antibodies in rabbits which formed a single precipitin line against the crude extract. The purified antigen (DP-2) from a Type 1 strain was antigenically distinct from a similar antigen purified from a Type 3 strain; there was no significant cross protection in turkeys between the 2 antigens. These results indicate that protective antigens purified from soluble extracts of a Type 1 or Type 3 strain possess similar physicochemical properties, but that they are immunologically distinct from each other.     

A preliminary serological survey of viral antibodies in Peruvian sheep

This study reports the sero-prevalence of viral infections in sheep in Peru. Serum samples were collected from 34 mature healthy rams located in 3 different geographic regions of the country (north, central and south). The sera were tested for antibodies to the following viruses: respiratory syncytial virus (RSV); parainfluenza 3 (PI-3) virus; bovine viral diarrhea/border disease (BVD/BD) virus; bovine herpesvirus 1 (BHV-1); bluetongue (BT) virus; ovine progressive pneumoniae (OPP) virus; bovine leukosis virus (BLV). The serological studies showed that 47% were positive for RSV; 82% for PI-3; 3% for BVD/BD virus; 49% for BT virus; 13% for OPP virus. Antibodies were not detected to bovine herpesvirus 1 or to bovine leukosis virus.     

Growth hormone secretion in chicks during dietary calcium deficiency

The role of calcium in the secretion of growth hormone (GH) has been examined in vivo in immature domestic fowl. Chicks reared on a low calcium (0.16% calcium in the feed) diet showed a reduced growth rate, compared with those on a normal (0.86%) calcium diet and had lower basal levels of plasma GH 1, 5, 10 and 15 d after calcium deprivation, but not after 20, 25, 30 or 35 d of calcium deficiency. No consistent changes in the concentration of immunoreactive somatomedin C were observed during calcium restriction. In both the control and low calcium fed birds the plasma concentrations of GH were elevated by the intravenous administration of human pancreatic GH releasing factor (hpGRF) and by thyrotropin releasing hormone (TRH). The GH responses to these provocative stimuli were not reduced in magnitude by calcium deficiency. It is suggested, therefore, that the effect of calcium deprivation on the secretion of GH is mediated via the reduced release of stimulatory hypophysiotrophic factors from the hypothalamus.

Pharmacological alterations in calcium status also suggest that calcium deprivation inhibits GH secretion. Plasma concentrations of GH were acutely depressed in young chicks following the administration of a calcium chelator (ethylene diaminotetraacetic acid) a calcium channel blocker (verapamil) and after calmodulin inhibition (by chlordiazapine and trifluorpenazine administration). These data therefore demonstrate the importance of calcium in the stimulation of GH secretion in the domestic fowl.     

Swine trichinosis in mid-atlantic slaughterhouses: Possible relationship to hog marketing systems

Digests of diaphragms from 33 482 hogs slaughtered in the mid-atlantic states were examined for the presence of Trichinella spiralis larvae. The samples were obtained from 7 slaughterhouses, ranging in slaughter capacity from less than 50 per day to more than 4000 per day. The sources of the hogs varied from “backyard” operations, raising hogs for home use, to commercial farms. The means by which hogs were brought to the slaughterhouse also differed; the larger slaughterhouses often purchased directly from the producer while the smaller slaughterhouses (1000 hogs per day or less) usually purchased through dealers or brokers. Infected hogs were detected more frequently than was expected from previously-published prevalence studies; overall, 0.58% of samples examined contained T. spiralis larvae. All of the infected hogs were marketed through the smaller slaughterhouses (less than 1000 per day) and nearly all were marketed through brokers. The mean number of larvae per gram of diaphragm, determined by slaugterhouses type, ranged from 0.5 to 74.6; most infections were light although 5 had counts of 1000–2480.Most of the positive samples were obtained from one slaughterhouse, the data from which exhibited marked differences in the frequency of infection by day of the week; 128 positive samples of the total of 190 found were obtained on Fridays, although only 10% of all samples were obtained on that day. Analysis of the geographic origin of shipments containing infected hogs revealed that most originated in New Jersey and Pennsylvania, although the hogs shipped from the latter state might originated in New England or Maryland. Attempts to trace back infected hogs for further epidemiological investigation were largely futile, owing to the absence of an identification system.     

Studies on fascioliasis in four selected sites in Ethiopia

The incidence of fascioliasis was studied in Asela, Awasa, Debre Zeit and Debre Berhan by using 153 experimental sheep divided up into 4 groups designated tracer sheep, Controls I, II and III. Fasciola hepatica was encountered in Debre Berhan, Asela and Awasa, but it was not detected at Debre Zeit. In all areas, it was most frequently recovered after heavy rains. Altitude, soil type, salt content and local crowding of animals in watering sites appear to have influenced the varying degrees of incidence and intensity of infection.     

Half-life,clearance and production rate for oxytocin in cattle during lactation and mammary involution I

Basal concentration, production rate, metabolic clearance rate and $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ for oxytocin were measured in Holstein cows at three lactational stages and during mammary involution. At each lactational stage, oxytocin was given intravenously at .5 IU/min or 1.0 IU/min for 60 min. Infusions were preceded by priming. During involution, the high dose was used. Mean basal concentrations of oxytocin ranged from 8.7 to 21.4 uU/ml. Mean basal values at early, middle, late lactation and involution were 17.57, 12.33, 15.15, 21.13 uU/ml, respectively and differed significantly. The mean “rapid” $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ was 3.87 ± .1 min. Early, middle, late lactation and involution $\text{T}\text{1}\text{2}\text{s}$ were 4.2, 3.7, 4.0 and 3.5 min, respectively. The rapid $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ was not affected by lactational stage. The mean “slow” $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ was 25.53 ± 1 min. Early lactation and dry period means differed significantly. The overall mean oxytocin clearance rate was 8.41 ± .1 ml/kg^·min. Clearance rate declined through lactation and into the dry period. Mean values of 9.3, 8.8, 7.8 and 7.1 ml/kg^·min were obtained at early, middle, late lactation and involution, respectively. Clearance rates at late lactation and involution differed significantly from one another and from the early and middle stages. Mean entry rates for oxytocin at early, middle, late lactation and involution were 168.79, 106.03, 111.1 and 146.8 uU/kg^·min, respectively. Measurements at early lactation and involution were greater than values for middle and late lactation. To summarize, basal oxytocin concentrations can be measured in cows that are lactating or undergoing mammary involution and changes in concentrations during lactation are related to hormone production (entry rate) and metabolic clearance rates.     

Radioimmunoassay for β-endorphin/β-lipotropin in unextracted plasma from sheep

A double antibody radioimmunoassay (RIA) was developed and validated for the quantification of β-endorphin (EP) in unextracted plasma from sheep. The RIA crossreacted on a molar basis approximately 100% with β-lipotropin (LPH). Almost all of the immunoreactivity in silicic acid extracts of plasma migrated on gel filtration as either EP or LPH. Incubation of radioiodinated EP with unextracted plasma under assay conditions resulted in the formation of a radioiodinated product which could still bind to the anti-EP serum. Basal concentrations of EP/LPH ranged from .1 to .2 ng/ml plasma, but transient peaks of 1.4 to 2.4 ng/ml were sometimes observed.     

Comparison of mycoplasma ovipneumoniae isolates using bacterial restriction endonuclease DNA analysis and SDS-PAGE

Sixteen isolates of Mycoplasma ovipneumoniae recovered from the nasal tract or lungs of sheep from different flocks in New Zealand were examined by bacterial restriction endonuclease DNA analysis (BRENDA) using EcoR1 and by sodium dodecyl sulphate-polycrylamide gel electrophoresis (SDS-PAGE). All isolates gave BRENDA patterns which differed entirely from one another. Following 20 serial passages (corresponding to approximately 67 generations) of an isolate, no charge was detected in the BRENDA pattern.

When eight isolates were examined by SDS-PAGE most bands were common but, nevertheless, each isolate was unique in the sense that they differed from one another in one or more bands. The marked heterogeneity of patterns observed when strains of M. ovipneumoniae are compared by BRENDA, together with the stability of such patterns over many generations, will enable this approach to be used to study the epidemiology of individual strains of M. ovipneumoniae with a flock.     

Kinetics of infection with Theileria parva (East Coast fever) in the central lymph of cattle

During the course of a lethal infection with Theileria parva in susceptible cattle, the dissemination of the parasite was examined in central lymph efferent from superficial lymph nodes in the thoracic duct. From the regional node, lymphocytes containing macroschizonts of T. parva were detected in efferent lymph 8 days after challenge where their appearance coincided with a dramatic increase in the output of lymphoblasts. The number of infected cells reached a maximum around Day 14, when 60-65% of efferent lymphocytes were parasitized. A severe reduction in the total cell output occurred after Day 14, at the time when widespread lymphocytosis was observed in the parent lymph node. A similar pattern of cellular kinetics was observed in the thoracic duct and in lymph efferent from lymph nodes distant from the site of challenge, although in the latter, the parasitosis reached only 10% of total cells. There was no selective depletion of parasitized cells from central lymph during the third week of infection, although the comparative parasitosis between lymph and lymph node cells indicated that infected cells entered central lymph less readily during this period. Macroschizonts appeared in cultures of lymphatic lymphocytes sampled between 5-9 days after challenge. These results, together with the failure of ablation of the regional lymph node 2, 3 or 5 days after challenge to delay the onset of the disease, indicated that dissemination of the infection from the site of challenge occurred within the first 2-3 days after the inoculation T. parva.     

Dirofilariasis in wild canids from the Gulf coastal prairies of Texas and Louisiana,U.S.A.

Heartworms, Dirofilaria immitis, were recovered from 17 out of 24 (71%) coyotes, Canis latrans, 38 out of 46 (83%) coyote × red wolf hybrids and all of 8 (100%) red wolves, Canis rufus gregoryi, collected from the Gulf coastal prairies of southeast Texas and southwest Louisiana. Intensities of infection ranged from 1 to 176 ($\text{x}\text{=25}$) worms per host. There was a significantly (P<0.05) higher intensity of infection in red wolves. Prevalence of heartworms increased significantly with increasing age. There were no significant differences between coyotes, hybrids and red wolves or between different host sexes in terms of prevalence. The female to male ratio of heartworms was close to unity (1.2:1) and was not correlated with worm burdens. Nematodes were primarily localized in the right heart, frequently extending into the pulmonary artery and the pulmonary arterial tree in the lungs. In 13 instances, 1–4 adult heartworms were recovered from the venae cavae. Pathological responses in the right heart were variable, depending on the intensity of infection. In severe infections, there were small areas of infarctive necrosis with mild to severe interstitial edema in the myocardium. Lesions in the pulmonary artery and pulmonary arterial trunk varied from mild focal hyperplastic intimal changes to extensive exudative villous endarteritis. The latter was characterized by a hyperplastic collagenous stroma with numerous histiocytes, plasma cells and eosinophils. Lung pathology varied from patchy to extensive areas of congestion, edema, hemorrhage, interstitial pneumonitis and infarction. In cases with heartworms in the venae cavae, hepatic changes were minimal and associated with liver changes such as passive congestion and centrolobular necrosis seen in cases without adult worms in the venae cavae. In heavily infected animals, hemosiderosis of the liver, spleen and kidneys was pronounced. A microfilaremia was noted in 46% of the infected wild canids. Microfilariae were observed in tissue sections of the myocardium, lungs, liver, kidney, spleen, lymph nodes, pancreas and appendix. Wild canids from this area are regarded as natural definitive hosts and primary reservoirs for heartworms and it appears that this infection is an important factor in the morbidity and mortality of these hosts.     

Enzyme-linked immunosorbent assay for the detection of antibodies to bovine viral diarrhea virus in bovine sera

A specific and sensitive enzyme-linked immunosorbent assay (ELISA) was established for the detection of antibodies to bovine viral diarrhea virus (BVDV) in bovine sera. Polyethylene-glycol concentrated, equilibrium density gradient purified BVDV was used as test antigen at an optimal amount of 1 microgram/well, whereas the optimal concentration of conjugate was at 1/2000 dilution. The standardized test encountered no non-specific reaction with test sera at a starting dilution of 1/10. A total of 50 bovine serum samples was assayed for the presence of antibodies against BVDV by ELISA and serum neutralization test (SNT). A positive correlation between the 2 tests was found. However, ELISA could be as much as 500-fold more sensitive than SNT in detecting low levels of BVDV antibodies.     

Analysis and in vivo assay of B. abortus agglutinating and non-agglutinating antibodies

Studies were made of physicochemical and immunochemical characteristics of Brucella abortus agglutinating and non-agglutinating antibodies in the sera of cattle repeatedly injected with living B. abortus (Strain 1119). Both agglutinating and non-agglutinating antibody were shown to be IgG1, and by immunodiffusion against rabbit anti-cattle gamma-globulin, agglutinating antibody gave a precipitation line of identity with that given by non-agglutinating antibody. Whilst agglutinating antibody increased clearance of antigen from the blood of passively protected mice, non-agglutinating antibody did not enhance clearance. Determination of the spleen infection index in mice pre-treated with agglutinating and non-agglutinating antibody showed that in animals passively immunized with non-agglutinating antibody the number of living (infecting) bacteria was approximately 4 times higher than in the case of agglutinating antibody. The possible potentiation of chronic B. abortus infection by non-agglutinating antibody is discussed.     

Normal sexual maturation and reproductive function in domestic hens following unilateral adrenalectomy

The ovulation-inducing properties of adrenal hormones and the anatomical juxtaposition of the left adrenal gland and the ovary suggest that a functional relationship exists between these two endocrine organs. To test this hypothesis, the effect of unilateral adrenalectomy on sexual maturation and reproductive function was examined in left and right adrenalectomized SCWL pullets. Between 9 and 13 weeks of age, 24 and 12 pullets were either left or right adrenalectomized, respectively; 12 birds were sham operated and 7 birds served as unoperated controls. Blood samples were obtained immediately before and after surgery, 48h after surgery and at 14, 19 and 23 weeks of age. All samples were analyzed for plasma corticosterone by radioimmunoassay. At 20 weeks of age all birds were weighed and the photoschedule was changed from 8L:16D to 16L:8D. During the first 52 days following photostimulation the age at first egg and the distribution of ovipositions within the 24h photoschedule were recorded.Mean plasma corticosterone levels of the unilaterally adrenalectomized hens were not significantly different (P > .05) from those of control birds 48h after surgery or at 14, 19 and 23 weeks of age. Unilateral adrenalectomy had no effect on body weight at 20 weeks, average age at first egg, or percent hen-day production. In addition, 95% of the eggs laid in the first 52 days after photostimulation were restricted to a 10 hour period of the day regardless of the surgical treatment. These observations indicate that the removal of either the left or the right adrenal gland does not affect plasma levels of corticosterone, sexual maturation, or the open period for LH release as evidenced by the times of oviposition and fail to support the hypothesis of a localized functional relationship between the left adrenal gland and the ovary.     

Oxytocin concentrations of cattle in response to milking stimuli through lactation and mammary involution II

Patterns of oxytocin release to milking stimuli over a lactation and during mammary involution, were examined in seven Holstein cows used in the previous study. Blood samples were taken before, during and after milking or udder massage. Oxytocin as measured by radioimmunoassay increased within O to 2 min after attachment of the milking unit. Oxytocin levels fluctuated during milking and declined after the initial increase. Oxytocin often dropped below basal levels after milking. Milking-induced oxytocin release decreased as lactation advanced. The maximal increment for oxytocin release was significantly different between early and late lactation. The time taken to reach peak hormone concentrations declined across lactation. Relative amounts of oxytocin released in response to milking stimuli were significantly more in early than during late lactation. Cows released oxytocin during mammary involution with relatively large, rapid increases to udder massage. A distinct peak was observed and return to basal concentrations was rapid. The mean increment of oxytocin concentration above basal was 51.6 ±10.1 uU/ml. Maximal oxytocin levels occurred 1.6 ±.2 min (0 to 2 min) after initial stimulation. The total amount of oxytocin released in response to stimulation was 1.2 ±.1 uU/ml. In summary, a continuous or multiple release of oxytocin occurs during milking. The sensitivity of the neuroendocrine reflex for oxytocin appears dynamic. Changes in maximal concentrations and total amounts of hormone released in response to milking during lactation, and the relationship between these variables and basal concentrations suggest a gradual loss of sensitivity from the early stages of lactation to mammary involution.     

Search for an antigenic relationship between aeromonads and Brucella abortus

A. hydrophila, A. punctata subsp. vaviae, A. salmonicida, and Plesiomonas shigelloides strains did not serologically react with three strains of Brucella abortus when tested by serum agglutination, immunodiffusion, and immunoelectrophoresis.     

Epidemiology of theilerioses in the Trans-Mara division, Kenya: Husbandry and disease background and preliminary investigations on theilerioses in calves

All the calves born (116) into 3 Maasai cattle herds in the Trans-Mara Division of Kenya, between August 1978 and October 1979, were recruited into a monthly health study which concentrated on theileriosis. Twenty-two of the calves died before they were 6 months of age, but the mortality only increased to 25% by the time the calves reached 18 months of age. The mean birth weight of calves was 17.5 kg while at 190 days post-birth the mean weight was 53.4 kg. The main causes of mortality were starvation (7.8%), neonatal diarrhoea (2.6%), chronic indigestion (2.6%) and theileriosis (2.6%) due to Theileria parva and T. mutans infections. The calves were infected with ticks from birth (mostly Rhipicephalus appendiculatus and Amblyomma spp.) and the first Theileria schizonts were detected on Day 17 post birth and reached a maximum of 18.4% of calves in the 11th week post-birth. Seasonal peaks of macroschizont incidence occurred in February and July. All calves had patent Theileria piroplasm infections by the time they were 5 months old and 44% had shown patent Theileria macroschizont infections by 6–7 months of age. Generally low parasitosis of Theileria piroplasms and schizonts occurred. Serology using the indirect fluorescent antibody test showed a high proportion of calves received antibodies against T. mutans and T. parva from their dams by way of colostrum. The majority of calves also had active antibody responses against T. mutans and T. parva by the time they were 6 months of age. There was a correlation between the pre-patent period of piroplasms and active antibody responses to T. mutans and between the prepatent period of schizonts and an antibody response to T. parva. Eighteen older calves developed T. velifera infections. “Turning sickness” due to Theileria infection in the brain was detected in older cattle. Other blood parasites such as Trypanosoma vivax, T. congolense, Anaplasma marginale and Babesia bigemina occurred at patent levels at a lower incidence than Theileria spp. and did not cause disease problems in the calves. The calf population was highly resistant to theileriosis since they had a 100% morbidity, but only 2.6% mortality. Theileria infections would appear to have an important effect on the growth of calves but this and many aspects of the epidemiology of theileriosis in the area required more intensive sampling.     

Isolation of enterotoxigenic strains of staphylococci from dogs

The ability of 309 staphylococcal isolates from household dogs to produce enterotoxin, coagulase, thermonuclease and hemolysin was investigated. A total of 52 (16.8%) isolates from 45 out of 150 dogs examined were enterotoxigenic when tested for enterotoxin types A, B and C. Based on sites sampled, 33 (20.5%) out of 161 isolates from the anterior nares were enterotoxigenic while from dorsal skins 19 (12.8%) out of 148 isolates were enterotoxigenic. Staphylococcal enterotoxin C(SEC) was predominantly produced as 21 (6.8%) isolates elaborated it and also accounted for 40.4% of all enterotoxins produced by isolates. Staphylococcal enterotoxins A(SEA) and B(SEB) were produced by 10 (3.2%) and 16 (5.2%) strains, respectively. Mixed enterotoxin types AB, AC and BC were produced by 1,3 and 1 strains, respectively. With human plasma, 17.1% of coagulase-positive and 15.0% of coagulase-negative strains were enterotoxigenic. However, using canine plasma, 19.1% and 6.9% of the coagulase-positive and negative isolates, respectively, were enterotoxigenic. The incidence of enterotoxigenicity was 16.9% amongst thermonuclease-positive isolates and 16.3% for thermonuclease-negative strains.Alpha hemolysin was predominantly produced by 180 (60.2%) isolates and 19.9% of these were enterotoxigenic. Beta hemolysin was produced by 36 (11.7%) isolates with 13.9% enterotoxigenic, while 87 (28.2%) exhibited gamma hemolytic pattern amongst which 11.5% were enterotoxigenic.Based on data provided on coagulation of human and canine plasmas and hemolytic patterns, it is concluded that a large proportion of canine isolates from this environment are not of canine biotypes, but are most probably human biotypes.     

Restriction endonuclease analysis of Brucella ovis and other Brucella species

Brucella ovis DNA was analysed by using 11 different restriction endonucleases. The most clearly resolved DNA fragment patterns were obtained after digestion with the enzyme Hind III. When DNA preparations from 35 strains of B. ovis were digested with this enzyme, the fragment patterns appeared to be identical. The patterns obtained after Hind III digestion of DNA from one strain each of B. abortus, B. canis and B. melitensis were more similar to each other than to the B. ovis pattern.     

The effects of dl-tetramisole and rafoxanide on tricarboxylic acid cycle enzymes of Haemonchus contortus, in vitro

Various enzymes of the tricarboxylic acid cycle (TCA) viz., aconitase (E.C. 4.2.1.3), isocitrate dehydrogenase (E.C. 1.1.1.42), succinate dehydrognease (E.C. 1.3.99.1), fumarate reductase (NADH: fumarate oxido-reductase), fumarase (E.C. 4.2.1.2) and maltate dehydrogenase (E.C. 1.1.1.37) were detected in adult Haemonchus contortus (Nematoda: Trichostrongylidae), in vitro. Low activities of aconitase and isocitrate dehydrogenase suggested that the TCA cycle has a minor function and the pathway of CO₂ fixation is the major pathway in the energy metabolism of the parasite. In vitro incubation in Tyrode's solution had no significant effect on TCA cycle enzymes and the worm was able to maintain normal metabolism for 12 h.The effects of dl-tetramisole and rafoxanide on various enzymes of the TCA cycle were studied in adult H. contortus. At 50 μg ml^?1 varying degrees of succinate dehydrogenase and fumarate reductase activities were observed. At the same concentration, the activities of other enzymes remained unaltered.     

Development of villus atrophy in the small intestine of sheep infected with Trichostrongylus rugatus

Pairs of sheep infected with 120 000 larvae of Trichostrongylus rugatus were killed at intervals from 2 to 56 days after infection (DAI). Worms were located in tunnels in the epithelium of villi or upper intestinal crypts at all stages of development. Villus atrophy developed progressively until 16 DAI, when surface microtopography, characterised by subtotal villus atrophy, stabilised. Most severe lesions were in the first 3 m of small intestine where the density of nematodes was highest. Discontinuities in the epithelium and effusion of inflammatory cells and tissue fluids into the lumen were rare. No effects of infection on body-weight gain, appetite or serum total protein and albumin were evident in the first 20 days of infection. However, it was concluded that T. rugatus fundamentally resembled T. colubriformis and T. vitrinus in the response it elicited in the intestine of sheep, and must be considered potentially pathogenic.