Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SHEEP”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources
PubMed1989

Restricted expression of CD2 among subsets of sheep thymocytes and T lymphocytes.

A monoclonal antibody (mAb) generated against sheep T-cell blasts, called I/35 A, blocks sheep autologous E rosetting and competes with purified T11 target structure (TS), the sheep form of LFA3, for binding sites on the sheep T-cell surface. Immunoprecipitation from lysates of surface iodinated sheep T cells identifies the cell surface molecule recognized by mAb I/35 A as a single chain polypeptide migrating as a diffuse band of MW 55,000. From its binding properties and the biochemical nature of the target antigen, we conclude that mAb I/35 A is directed at sheep CD2. This finding makes sheep the first animal model in which the CD2-LFA3 (T11TS) system is defined by mAbs to both receptor and ligand. When analysed by two-colour flow cytometry and by immunohistochemistry, the cellular expression of CD2 in sheep differs significantly to that reported in humans. In peripheral blood, CD2 is found exclusively on CD4+8- and CD4-8+ T cells, while the third, CD4-8- (predominantly SBU-T19+) subset of sheep T cells (around 20% in peripheral blood) is CD2-. In thymus, only low to moderate levels of CD2 expression occurs on 80% of cells. Among these, medullary 'single positive' thymocytes express the highest level of CD2, whereas the CD4-8- 'double negative' population (which in contrast to peripheral CD4-8- T cells contains only very few SBU-T19+ cells) consists of CD2- and weakly positive cells. In peripheral lymphoid organs, CD2+ lymphocytes occur in the T-cell regions of spleen, lymph nodes and jejunal Peyer's patches (JPP). Tissue macrophages found in B-cell follicles of lymph nodes and JPP are also CD2+. The implications of these findings are discussed in terms of the role CD2 plays in the proliferation of immature thymocytes and of the possible importance of CD2/LFA3 interactions in lymphocyte recirculation.

Animals↗
PubMed1986

Forestomach epithelial receptor activation by rumen fluids from sheep given intraruminal infusions of volatile fatty acids.

Forty-four reticuloruminal epithelial receptors were tested with rumen fluids obtained from 12 sheep before they were intraruminally infused with 4.0M acetic acid (8 sheep) or 4.0M butyric acid (4 sheep; preinfusion rumen fluid) and with rumen fluids obtained at the onset of ruminal stasis (abolition rumen fluid). The preinfusion rumen fluids from the 8 acetic acid-infused sheep (mean pH, 6.55) contained 1.7 mM nondissociated volatile fatty acids (VFA)/L and excited none of the 25 receptors tested. Preinfusion rumen fluids from the 4 butyric acid-infused sheep (mean pH, 6.98) contained 0.3 mM nondissociated VFA/L and also did not evoke responses in any of the 19 receptors tested. Abolition rumen fluids from sheep treated with acetic acid excited 17 of the 25 receptors tested and contained 89.4 mM nondissociated VFA/L, of which nondissociated acetic acid comprised 85.0 mM/L. Abolition rumen fluids from sheep treated with butyric acid activated 14 of the 19 receptors tested and contained 61.1 mM nondissociated VFA/L, of which 38.7 mM/L was nondissociated butyric acid. Preinfusion rumen fluids whose pH values were adjusted to that of abolition rumen fluids with HCl contained nondissociated VFA levels ranging from 16.3 mM/L (acetic acid-treated sheep) to 20.6 mM/L (butyric acid-treated sheep) and elicited responses in 4 of 30 receptors tested. Preinfusion rumen fluids whose pH values were adjusted to the pH value of abolition rumen fluid with acetic acid contained 29.5 mM nondissociated VFA/L and excited 7 of 13 tested receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1988

Pulmonary removal of circulating endotoxin results in acute lung injury in sheep.

Endotoxemia has often been associated with the development of the adult respiratory distress syndrome. Our previous studies have shown that sheep, a popular animal model for adult respiratory distress syndrome, have abundant resident pulmonary intravascular macrophages that rapidly remove inorganic particles and live bacteria from the circulating blood. In this study, we examine the fate of circulating endotoxin in sheep and correlated the site of uptake with early morphologic evidence of tissue injury. Mature sheep and rats received intravenous 125I-labeled lipopolysaccharide (LPS). The dose was 0.8 microgram/kg in sheep and 17.0 micrograms/kg in rats. 125I-LPS clearance from the blood was assayed by gamma-counting of blood samples drawn over 1 hour and was correlated with circulating leukocyte numbers. The distribution of 125I-LPS was determined by gamma-counting of samples of major organs and tissues at time of necropsy. Lungs and liver were examined morphologically in both species. The half-life of circulating 125I-LPS was 2.38 minutes in sheep, and 12.39 minutes in rats. The endotoxin content of the lungs after injection was 77.58% of the total recovered dose in sheep, but only 2.02% in rats. Neutrophil margination occurred in the lungs of both species. In sheep, almost 25 minutes elapsed before peripheral neutrophil numbers decreased by 50%, much longer than the time required for LPS sequestration in the lungs. Rapid LPS uptake by the sheep lungs was associated with early (10-minute) ultrastructural changes including signs of pulmonary intravascular macrophage activation and microvascular congestion. By 60 minutes, many capillaries were occluded with neutrophils, platelets, and fibrin. There was interstitial edema, and endothelial cells showed evidence of severe injury. We conclude that in contrast to the rat, the sheep clears circulating endotoxin more rapidly and preferentially sequesters it in the lungs. Subsequent release of mediators by activated pulmonary intravascular macrophages may then lead to influx of other inflammatory cells and cascading injury.

Animals↗
PubMed1988

Isolation and identification of mycoplasmas from the nasal cavity of sheep.

Mycoplasmas isolated from the nasal cavity of sheep in a ram test station were examined to determine their identity and prevalence. Specimens were obtained for mycoplasmal culture in 1980, 1982, and 1983 from 558 sheep, and mycoplasmas were isolated from 630 specimens from 320 sheep (57.3%). The isolates were characterized and differentiated into groups on the basis of sensitivity to digitonin, fermentation of glucose, and hydrolysis of arginine. Isolates in some groups were further characterized by use of additional diagnostic media, and their identity was confirmed by agglutination or growth inhibition with antiserum prepared from reference mycoplasmas. Of the 320 sheep with mycoplasmas, 293 had Mycoplasma ovipneumoniae, 12 had M arginini, and 1 had M capricolum. Two sheep had Acholeplasma spp, and 3 sheep had unidentified Mycoplasma spp. The remaining 9 sheep had M ovipneumoniae in combination with Acholeplasma spp (n = 3), M arginini (n = 3), M capricolum (n = 2), and an unidentified Mycoplasma spp (n = 1). The biochemical reactions of the M ovipneumoniae from the 293 sheep were similar, but varied in the degree of growth and fermentation in the basal medium containing glucose. The high prevalence of M ovipneumoniae indicated that it may be commensal in the upper respiratory tract of healthy sheep.

Animals↗
PubMedDate not supplied

[Kidney retention of urea in sheep on a hypoprotein diet: study by retrograde perfusion of urea in the kidney pelvis].

In order to study the role of the renal pelvis on urea sparing in sheep fed low protein diets, the pelvis was perfused through the ureter with 1M and 3M urea solutions. Eight ewes were used: four on a regular diet (total nitrogen 188.7 g.kg-1 dry matter) and the other four on a low protein diet (total nitrogen 109.4 g.kg-1 dry matter). On each animal, perfusions were performed on one kidney; the other one was kept as a control. Fractional excretion of urea (TEu) and urea (Cu), inulin, para-aminohippurate and osmolar clearances, were determined during five experimental periods of 30 min each (T = control, 1M = perfusion with 1M urea solution, R1 = first period of recovery, 3M = perfusion with 3M urea solution, R2 = second period of recovery). 1. During control periods sheep on low protein diet have a greater capacity of urea retention than sheep on regular diet, under antidiuretic conditions (inulin U/P = 200). The following data (means +/- S.D.) are all reduced in animals on low protein diet: TEu by 36% (0.38 +/- 0.19 vs. 0.59 +/- 0.28 for normal protein sheep, p less than 0.05), Cu by 55% (0.50 +/- 0.19 vs. 1.15 +/- 0.49 ml.min-1.kg-1 for normal sheep, p less than 0.01) and amount of urea excreted by 80% (2.1 +/- 0.7 vs. 10.4 +/- 2.7 mg.min-1 for normal sheep, p less than 0.01). 2. The linear regression analysis of the relationship between tubular reabsorption of urea and its filtered amount shows that the capacity of urea retention is significantly higher in low protein sheep and that the difference between the two groups is greater as the filtered amount increases. Following 1M and 3M perfusions, the capacity of urea reabsorption by the perfused kidneys is significantly decreased in low protein animals whereas there is no change in the normal ones. The result is that perfused kidneys of the low protein sheep increase the amount of urea excreted during these periods: urine concentration of urea (Uu) increases by 55% during R1 and by 144% during R2, TEu increases by 60% during R1 and by 147% during R2 and Cu increases by 40% during R1 and by 95% during R2, without any variation of urine flow rate. These changes could be understood, provided that an important transfer of the perfused urea to the renal medulla in the low protein sheep would reduce the concentration gradients which enhance urea passive reabsorption from the collecting ducts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Comparison of resuscitation of sheep and dogs after bupivacaine-induced cardiovascular collapse.

This study evaluated interspecies sensitivity and ability to resuscitate pentobarbital anesthetized sheep and dogs after cardiovascular toxic doses of bupivacaine. Every minute, 3 mg/kg of bupivacaine was injected into the right atrium over the course of 10 sec until cardiovascular collapse occurred. While the bupivacaine was given, the animals were made apneic for 90 sec and then ventilated with 100% oxygen. After the bupivacaine administration, cardiovascular collapse occurred in the form of electromechanical dissociation progressing to asystole in dogs, whereas in sheep the predominant rhythm was ventricular fibrillation leading to asystole. Resuscitation was performed using open chest heart massage, bretylium for treatment of ventricular tachycardia and fibrillation, and epinephrine with atropine for treatment of electromechanical dissociation or asystole. The initial dose of bupivacaine used to cause cardiovascular collapse was 3.5 +/- 1.2 mg/kg in sheep and 24.6 +/- 8.5 mg/kg in dogs (P less than 0.01). All sheep and dogs were resuscitated from the first cardiovascular collapse. The resuscitation time was 2.1 +/- 1.0 min in dogs and 36.9 +/- 15.4 min in sheep (P less than 0.01). All dogs could be resuscitated after two additional cardiovascular collapses induced by bupivacaine, but no sheep could be resuscitated after a second cardiovascular collapse. Concentrations of bupivacaine in cardiac tissue and serum levels of bupivacaine after the last resuscitation attempt were significantly greater in the dogs than in the sheep. We conclude that sheep are more sensitive to bupivacaine than dogs, but that even sheep can be resuscitated after cardiovascular collapse produced by bupivacaine.

Animals↗
PubMed1984

[Blood serotonin and histamine in sheep with endemic scrapie: initial results].

The whole blood histamine levels of sheep without clinical scrapie but living in infected farms, control, and scrapie infected sheep are not significantly different. By contrast whole blood serotonin is decreased both in sheep living in infected farms and in scrapie-infected sheep as compared to controls. Thrombopenia may account for the hyposerotoninemia of sheep living in infected farms except those genetically linked to scrapie-infected sheep for which, as for scrapie-infected sheep, platelet serotonin appears also to be diminished. Whole blood serotonin determination might therefore be useful to detect sheep living in infected farms (these sheep probably play an important role in scrapie infection) and perhaps also humans with high susceptibility to Creutzfeldt-Jakob disease.

Animals↗
PubMed1993

Aluminium inhalation in sheep silicosis.

In prior studies, we and others have documented a significant reduction by surface chemistry modification in the biological activity of quartz. We further documented that aluminium lactate inhalation one month after quartz exposure significantly suppressed the silica-induced alveolitis, reduced the pathological process and decreased the retention of quartz in the lung tissue. In the present study, we evaluated the efficacy of aluminium inhalation in altering the silicosis process after disease was recognized by standard chest radiography. Twenty-four sheep were enrolled in the study. The 14 silica exposed sheep had an abnormal chest radiograph of the ILO category 1 or above after 3 years of 100 mg Minusil-5 in 100-ml saline intratracheal injections. Ten control sheep were exposed to saline intratracheal injections. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage. At month 36 of the study, all 14 sheep had an abnormal chest radiograph while the radiographs of controls remained normal. The sheep with silicosis had significantly reduced lung functions and increased cellularity, phospholipids and hyaluronan. These changes persisted during the next 12 months without exposure or treatment. At month 48 and at monthly intervals after, for 12 months, aerosol inhalations were carried out with saline alone for control and seven silicotic sheep and with 100 mg of aluminium lactate in 10 ml saline generated with a Bird Mark 8 pressure ventilator for the other seven silicotic sheep. All sheep were evaluated at 3-month intervals by chest radiography, lung function and lung lavage.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1996

Comparative pharmacokinetics of an ampicillin/sulbactam combination administered intramuscularly in lactating sheep and goats.

The pharmacokinetic behaviour of an ampicillin/sulbactam (2:1) combination was studied after intramuscular administration of a single dose (20 mg/kg body weight: 13.33 mg/kg of ampicillin and 6.67 mg/kg of sulbactam) to six sheep and six goats. The objective was to determine whether there were differences between sheep and goats in the disposition profiles of ampicillin and sulbactam. The disposition curves for both drugs were best described by a biexponential equation (one-compartment open model with first order absorption) in both sheep and goats. The maximum plasma concentrations of ampicillin and sulbactam were similar in both sheep (10.61 +/- 6.36 and 9.17 +/- 3.82 mg/L respectively) and goats (11.02 +/- 2.69 and 9.25 +/- 0.85 mg/L respectively), in spite of the fact that the ampicillin dose was twice that of sulbactam. The time of the peak plasma concentration for both drugs was also similar in both sheep and goats. The elimination half-life of ampicillin was 0.81 +/- 0.17 h in sheep and 0.71 +/- 0.12 h in goats, and that of sulbactam was 1.02 +/- 0.36 h in sheep and 1.13 +/- 0.18 h in goats. The rate of drug removal from the body was faster in sheep than in goats and consequently the area under the curve was greater for goats. It was concluded that the similarity in the disposition and elimination of both drugs in sheep and goats indicated that the combination preparation could be administered at the same dosing rate in both species.

Ampicillin↗
PubMedDate not supplied

Border disease of sheep and goats.

Border disease (BD) is a congenital virus disease of sheep and goats first reported in 1959 from the border region of England and Wales. BD virus (BDV) is a pestivirus in the genus Flaviviridae and is closely related to classical swine fever virus and bovine virus diarrhoea virus (BVDV). Nearly all isolates of BDV are non-cytopathogenic (ncp) in cell culture. There are no defined serotypes but pestiviruses isolated from sheep exhibit considerable antigenic diversity and three distinct antigenic groups have been identified. Distribution of the virus is worldwide. Prevalence rates vary in sheep from 5 to 50% between countries and from region-to-region within countries. The disease in goats is rare and characterized by abortion. Clinical signs in sheep include barren ewes, abortions, stillbirths and the birth of small weak lambs. Affected lambs can show tremor, abnormal body conformation and hairy fleeces (so-called 'hairy-shaker' or 'fuzzy' lambs). Vertical transmission plays an important role in the epidemiology of the disease. Infection of fetuses can result in the birth of persistently infected (PI) lambs. These PI lambs are viraemic, antibody negative and constantly excrete virus. The virus spreads from sheep to sheep with PI animals being the most potent source of infection. Apparently healthy PI sheep resulting from congenital infection can be identified by direct detection of viral antigen or viral RNA in leukocytes or by isolation of ncp virus from blood or serum in laboratory cell cultures. Isolation of virus is unreliable in lambs younger than 2 months old that have received colostral antibody. The isolation of virus from tissues of aborted or stillborn lambs is difficult but tissues from PI sheep contain easily detectable levels of virus. To detect the growth of virus in cell cultures it is essential to use an immune-labelling method. Acute infection is usually subclinical and viraemia is transient and difficult to detect. Sheep may also be infected following close contact with cattle excreting the closely related BVDV.

Animals↗
PubMed2003

Trade-offs between social behaviour and foraging by sheep in heterogeneous pastures.

In heterogeneous pastures, groups of sheep may have to alter their social behaviour in order to graze patches of preferred vegetation. In this event, patch size, inter-patch distance and the contrast between patch and background vegetation are likely to affect behaviour. In this experiment, groups of five female Scottish Blackface sheep grazed for 2-h periods in 0.1ha grass plots containing seven 1.5mx1.5m patches of improved vegetation, with inter-patch distances of 1.5, 6 or 11.5m. Background vegetation was of either medium or poor quality. Control plots contained no patches. On average, sheep spent 44% of the time grazing patches, although patches comprised only 1.6% of the total plot area. Inter-patch distance did not affect accumulated time spent grazing patches during the first 30min, but patch residence time and the number of sheep on a patch increased with inter-patch distance. The distribution of nearest neighbour distances was altered when patches were 6 or 11.5m apart, compared to no patches. Accumulated time spent grazing patches and the number of sheep on a patch were greater with poor than medium backgrounds. Sheep visited patches frequently and for short periods and it is suggested that sheep often moved off patches as a result of competition. The results provide evidence that sheep make trade-offs between social and foraging behaviour and demonstrate the importance of interactions between social spacing and the size and spacing of vegetation patches, when sheep forage in heterogeneous pastures.

Journal Article↗
PubMed1968

Studies of haemoglobin types in barbary sheep (Ammotragus lervia).

1. Two haemoglobin types, haemoglobins Amm-C and Amm-B, were observed in five Barbary sheep (Ammotragus lervia). One animal was homozygous for haemoglobin Amm-C, a second was homozygous for haemoglobin Amm-B, and three were heterozygous for both. 2. Amino acid analyses of the globin from haemoglobin Amm-B showed that this type was related to, but not identical with, haemoglobin B of the domestic sheep. 3. The beta-chain of haemoglobin Amm-C was found to be composed of 141 amino acid residues. Its amino acid composition differed from that of the beta(C)-chain of the anaemic domestic sheep in at least 14 residues. The Amm-beta(C)-chain contained one isoleucyl residue. 4. The amino acid compositions of tryptic peptides T-1, T-2, T-13 and T-14 of the Amm-beta(C)-chain were similar to those of the sheep beta(C)-chain. Peptides T-3, T-4, T-6, T-7, T-8, T-11 and T-15 were the same as the corresponding peptides of the sheep beta(A)- and beta(C)-chains. Peptide T-5 and to a smaller extent peptide T-9 resembled the corresponding peptides of the sheep beta(A)-chain, and peptide T-10 was identical with peptide gammaT-10 of sheep haemoglobin F. Peptide T-12 was not recovered. 5. The results of these investigations were interpreted as being indicative that the structural Amm-beta(C)-gene is closely related to the beta(C)-gene of sheep, from which through domestication the present domestic sheep originated.

Journal Article↗
PubMed1995

Toxicity of Compound 1080 livestock protection collars to sheep.

The toxicity of Compound 1080 (sodium fluoroacetate) livestock protection collars (LPCs) to sheep was investigated. Lambs wearing punctured LPCs were observed to determine dermal toxicity, sheep were fed hay treated with LPC solution to find a lethal concentration, hay treated with a lethal concentration was subjected to sun and simulated rain to assess weathering influences, and sheep were held on pasture treated with LPC solution to evaluate grazing effects. Five lambs that wore punctured LPCs for up to seven days showed no dermal erythema or edema, but three died after ingesting 1080 from LPCs. All sheep died after eating 1.0 kg of hay treated with 3.75 ml, or more, of 1.0% LPC solution. Weathering 1.0 kg of hay treated with 3.75 ml of LPC solution in the sun for up to 12 weeks, reduced, but did not eliminate, toxicity; one inch or more of simulated rain eliminated toxicity. Survival of sheep in 250 m2 pens containing 1.1 m2 of forage treated with different amounts of LPC solution depended on the treatment and amount of treated forage consumed. LPC solution poses no dermal toxicity or irritation to sheep, and toxic effects on sheep from LPC solution on hay and forage was variable and situation dependent. Under conditions of exaggerated hazard, sheep can be poisoned by ingesting LPC solution, but adverse effects from normal LPC use are rare.

Animals↗
PubMed1994

The prevalence and intensity of infection with Eimeria species in sheep in Nyandarua district of Kenya.

The prevalence and numbers of coccidian oocysts in faecal samples from young (less than 6 months old), immature (6-12 months old) and adult (over 12 months old) sheep on 15 farms in Nyandarua district were studied during the dry and wet seasons. The species of Eimeria occurring in these sheep were also identified. The proportion of animals shedding coccidian oocysts did not vary significantly with season. The prevalence of the oocysts was significantly higher (p < 0.05) in young sheep (mean 85.3%) compared to immature (mean 40.2%) and adult sheep (mean 32.15%). OPG counts (oocysts per gram of faeces) were significantly higher (p < 0.01) in the young sheep compared to immature and adult sheep during both seasons. Prevalence and OPG did not differ between immature and adult sheep. There was no significant difference in OPG during the wet season (mean 328 +/- 997) compared to the dry season (mean 219 +/- 773). The sex of the sheep had no significant effect on prevalence or OPG. Eight species of Eimeria were recognized. They (and their prevalence) were E. bakuensis (ovina) (43.6%), E. ovinoidalis (23.6%), E. ahsata (15.2%), E. intricata (8.27%), E. granulosa (4.8%), E. faurei (2.8%), E. parva (1.06%) and E. pallida (0.67%).

Animals↗
PubMed1993

The effect of age on the response of Romney sheep to gastrointestinal nematodes during grazing.

Three groups of Romney sheep, reared worm-free in pens from birth until 4, 16 or 28 months of age, were permitted to graze nematode-infected pasture for 4 weeks after which they were returned to pens and slaughtered 4 weeks later. Three groups of three Romney sheep reared and maintained worm-free for similar periods served as uninfected control groups. Faecal egg counts (FECs) 8 weeks after grazing commenced were significantly greater in 4-month-old sheep than the 28-month-old animals. At slaughter, no difference in nematode burdens among these three age groups was found. Histological examination of the abomasal and small intestine mucosa, taken from sheep at slaughter, revealed significantly greater numbers of globule leukocytes/mucosal mast cells (GL/MMC) bur fewer connective tissue type mast cells (CTMC) in sheep aged 16 and 28 months than in those aged 4 months. The numbers of eosinophils in the gastrointestinal mucosal tissues of the three groups of infected sheep were not significantly different. In uninfected sheep the numbers of eosinophils, GL/MMC and CTMC in the mucosal tissues did not differ between the three age groups and the numbers of GL/MMC and CTMC were similar to those in 4-month-old infected sheep. Eosinophil numbers in the mucosal tissue of the infected groups were significantly higher than in the uninfected groups. In the infected groups, FECs but not worm burdens were significantly negatively correlated with GL/MMC numbers.(ABSTRACT TRUNCATED AT 250 WORDS)

Abomasum↗
PubMed1995

Immunization of sheep against parasitic nematodes leads to elevated levels of globule leukocytes in the small intestine lumen.

In sheep that had been given three immunizing infections with Trichostrongylus colubriformis and Ostertagia circumcincta infective (L3) larvae, drenched after the last infection and challenged with larvae of the same species, there was a significant increase in numbers of small intestine mucosal tissue globule leukocytes (TGLs) and lumenal globule leukocytes (LuGLs) compared with sheep that had only been drenched and challenged. There was a positive correlation between the numbers of LuGLs and TGLs in the small intestine but the ratio of these two cell types was lower in non-immunized than immunized sheep. In immunized sheep positive correlations were observed between LuGLs and levels of arylsulphatase and peroxidase in the intestinal mucus and between arylsulphatase and larval migration inhibition (LMI) activity in mucus. Lumen eosinophils correlated with blood eosinophils, serum antibody against T. colubriformis correlated with peroxidase in the mucus and blood eosinophils correlated with nematode specific IgM levels in the intestinal mucus. In the abomasum, TGLs were present but not LuGLs. Sheep repeatedly infected with T. axei also had significantly more LuGLs in the small intestine than control animals. Two sheep that had a surgically prepared isolated small intestinal loop, after oral infection with T. colubriformis had TGLs and LuGLs in the intact intestine, but not in the isolated loop. Significantly more LuGLs were produced in sheep by allowing repeated T. colubriformis L3 infections to develop to adult stages compared to sheep treated with the same number of larvae, but where the infections were terminated by drenching at various intervals.

Animals↗
PubMed1994

Antibody-containing cells in the abomasal mucosa of sheep with genetic resistance to Haemonchus contortus.

The frequency distribution of parasite-specific antibody-containing cells (ACC) and total immunoglobulin-containing cells (ICC) in the abomasal mucosa was examined in genetically resistant and random-bred sheep, following infection with Haemonchus contortus, to determine whether the two genotypes differed in the development of a local immune response. Immunofluorescence staining was used to detect ACC and ICC of IgA, IgG1, IgG2 and IgM classes. No ACC were found in the abomasum of any of the sheep before infection. ACC were first detected in the abomasal mucosa of both the resistant and susceptible sheep seven days after infection, reached a peak level on day 21 and then declined. At all observation times, the majority of ACC in both genotypes were of the IgA isotype, followed by IgG1 and IgM. The IgG2-ACC response was negligible compared with the IgA and IgG1 response. The comparison of genotypes showed that the resistant sheep had significantly more IgA-ACC on days 14, 21, 28 and 35, and significantly more IgG1-ACC than random-bred sheep on days 14, 21 and 28. The numbers of IgG2- and IgM-ACC did not differ between the genotypes. The abomasal mucosa of the resistant sheep was also found to have significantly more ICC than the mucosa of random-bred sheep; IgA-ICC predominated at all the observation times followed by IgG1 and IgM. These results suggest that IgA and IgG1 antibodies, produced locally in response to infection, may play a role in mediating genetic resistance to haemonchosis in sheep.

Abomasum↗
PubMed1995

Comparison of two enzyme immunoassays for the detection of Haemonchus contortus infections in sheep.

Two enzyme-linked immunosorbent assays (ELISA) using either excretory/secretory (ES) products or crude somatic antigens (CSA) of adult Haemonchus contortus were compared for their ability to detect antibodies against H. contortus in sheep. Serum samples obtained from a group of 32 H. contortus mono-infected sheep were tested in the two ELISAs and the obtained data were compared with the results of the faecal examinations of these sheep. The first sheep became patent 3 weeks post infection (p.i.) and all sheep had positive egg counts at week 5 p.i. The first antibodies against H. contortus were detected 1 week p.i. and all sheep were found positive by both ELISAs at week 4 p.i. Using sera from a large number of H. contortus-infected sheep a difference in sensitivity between the ES ELISA (97.7%) and the CSA ELISA (89.2%) was found. The specificity of each assay was determined by testing sera obtained from sheep with mono-infections of H. contortus, Trichostrongylus colubriformis, Trichostrongylus vitrinus, Ostertagia circumcincta, Nematodirus battus, Cooperia curticei, Fasciola hepatica, Taenia ovis or Eimeria spp. The specificity of the ES ELISA was 87.2%, whereas the specificity of the CSA ELISA was 82.7%.

Animals↗