Study on the pathogenicity of ostertagiosis due to Ostertagia circumcincta in sheep,in Iraq

The response of Awassi sheep to Ostertagia circumcincta, the most prevalent ovine strongylid species in Iraq, was studied.A dose of 100000 larvae of O. circumcincta (Iraqi strain) induced moderate clinical symptoms of ostertagiosis. These symptoms were correlated with elevated pH of the abomasal fluid and increased plasma pepsinogen levels. There was no evidence of larval inhibition since the majority of the fourth stage larvae (L₄) continued their development. No appreciable loss of worm population was observed and most of the parasites survived and exhibited a prolific egg-laying potential six moths after initial infection. Assessments of the pathophysiological changes were performed and correlated with parasitological and clinical observations.The Awassi breed of sheep, the most prevalent in the Arab Middle East, seems to be more susceptible to ostertagiosis than other breeds and there was no spontaneous self-cure in this breed.     

Increase in the prevalence of Johne's disease in sheep in Scotland

Increased prevalence of Johne's disease in sheep; abomasal damage in young cattle due to ostertagiosis; parasitic gastroenteritis in young sheep due to Nematodirus, Teladorsagia and Chabertia species; Streptococcus suis serotype 2 associated with a range of clinical signs in pigs; respiratory cryptosporidiosis confirmed in wild red grouse. These are among matters discussed in the disease surveillance report for October 2010 from SAC Consulting: Veterinary Services (SAC C VS).     

Abomasal disease in young beef calves: Surgical findings and management factors

A retrospective study was performed on 46 abomasotomies in young beef calves. Clinical abomasal disease in the herds under investigation had an average incidence of 1.0% for the year of the study. The range in incidence among herds was 0.2-5.7%. In 80% (37/46) of abomasal surgeries, abomasal ulcers were found. In 76% (35/46) of the cases, hair was present in the abomasum. These findings indicate that there could be a link between abomasal ulcers and the ingestion of hair by young beef calves.

Housing appeared to be a significant factor in relation to the relative risk of abomasal disease. Calves housed in pens or on stubble fields were nearly three times as likely to receive surgery for abomasal disease than were those housed on pasture.

The results also indicated that mineral supplements may be helpful in reducing the incidence of abomasal disease.

     

Synergistic influence of Ostertagia ostertagi and Trichostrongylus axei on Ostertagia ostertagi larval inhibition and abomasal lesions in cattle

Parasite-free 4-month-old calves were inoculated with Ostertagia ostertagi and/or Trichostrongylus axei followed 6 weeks later by increasing doses of O ostertagi for 8 weeks. Clinical signs of parasitism, fecal egg counts, and plasma pepsinogen concentrations were monitored, and gross lesions and parasite burdens were determined postmortem. Clinical signs of parasitism were not observed and weight gains were not affected in experimentally infected calves. In calves infected with O ostertagi, mean plasma pepsinogen concentrations were greater than for control calves and were diagnostically significant 4 weeks after inoculation and during the last 4 weeks of serial inoculations with O ostertagi. In calves that were given O ostertagi and T axei, abomasal pH was significantly increased, and abomasal lesions were more pronounced than in control calves or in calves inoculated with only O ostertagi or T axei. Abomasal lymph nodes were enlarged in all parasitized calves; other lymph nodes in the calves inoculated with both O ostertagi and T axei were usually smaller than in calves inoculated with only O ostertagi or T axei. Numbers of O ostertagi-inhibited larvae were small in all inoculated calves, but the percentage inhibition was significantly greater in calves inoculated with both O ostertagi and T axei. The percentage inhibition was 3.53% for the O ostertagi-inoculated calves and 7.07% for calves inoculated with both O ostertagi and T axei. These percentages indicated a synergistic effect of concurrent abomasal parasitism, whereas a synergistic effect on T axei worm burden was not observed. The low percentage of larval inhibition indicated that factors other than host resistance are involved in naturally occurring pretype II ostertagiosis.     

Nutritional sensitivity of resistance to Trichostrongylus colubriformis in lactating ewes

It has been suggested that the periparturient breakdown of immunity to parasites has a nutritional basis. Our overall hypothesis is that it results from a prioritized scarce metabolizable protein (MP) allocation to reproductive functions (e.g. milk production) rather than to immune functions. We have earlier shown that the relationship between MP supply, milk production and resistance to the abomasal nematode Teladorsagia circumcincta provides support for this hypothesis. Because nutritional sensitivity of resistance to parasites may differ between parasite species, we used the same nutritional protocol to test the overall hypothesis with a different parasite. Thus, five levels of dietary MP, ranging from 0.60 to 1.2 times assumed requirements, were offered for 4 weeks post-parturition to twin-rearing Greyface ewes, experimentally infected with the small intestinal nematode Trichostrongylus colubriformis. We hypothesized that the initial increments of MP supply would increase milk production without affecting the degree of breakdown of immunity whilst later increments would reduce the degree of breakdown of immunity. Indeed, the data suggest that the first two increments of MP supply increased milk production, whilst final worm burdens were reduced from the second increment onwards. MP supply did not affect mucosal mast cell concentration but increased globule leukocyte concentration. These results support the overall hypothesis that scarce MP allocation is prioritized to milk production over immune functions. In addition, the contrast between effects of MP supply on resistance to T. colubriformis and to T. circumcincta supports the view that periparturient immunity to small intestinal nematodes may be less sensitive to nutrient scarcity than periparturient immunity to abomasal nematodes.     

Isolation of Salmonella victoria from a cow

Extract

At the end of January 1972, specimens were submitted to this laboratory from a cow in the Geraldine district, which was one of three that died suddenly after transfer to a new, clover-dominant pasture. All apparently died from the same cause and post-mortem examination revealed reddened external mucosae, froth at nostrils, and gas distension of the carcasses. In addition, there was mild reddening of abomasal mucosa, severe reddening of intestinal mucosa, and congestion of the liver and lungs. Enterotoxaemia, salmonellosis, blood poisoning or irritant poisoning was suspected.     

Relationships Between Nutritional Condition of Adult Females and Relative Carrying Capacity for Rocky Mountain Elk

Lactation can have significant costs to individual and population-level productivity because of the high energetic demands it places on dams. Because the difference in condition between lactating and dry Rocky Mountain elk (Cervus elaphus nelsoni) cows tends to disappear as nutritional quality rises, the magnitude of that difference could be used to relate condition to habitat quality or the capability of habitats to support elk. We therefore compared nutritional condition of ≥ 2.5-yr-old lactating and dry cows from six free-ranging Rocky Mountain elk populations throughout the United States. Our goal was to quantify differential accrual of body fat (BF) reserves to determine whether the condition of dry and lactating cows could be used to define relevant management thresholds of habitat quality (i.e., relative carrying capacity) and consequently potential performance of elk populations. Levels of BF that lactating cows were able to accrue in autumn and the proportional difference in BF between dry and lactating cows in autumn were related (F_1–2,10 ≥ 16.2, P < 0.001). Models indicated that elk experienced no negative effects of reproduction on condition when lactating cows were able to accrue ≥ 13.7% BF in autumn. When lactating cows are accruing ≤ 7.9% BF, elk are in a nutritionally stressed condition, which may be limiting population performance. Using the logistic model to predict relative proximity to ecological carrying capacity (ECC), our population-years ranged from 3–97% of ECC and proportion of the population lactating (an index of calf survival) was negatively related to proportion of ECC. Results indicate that the proportional difference in accrual of BF between lactating and dry cows can provide a sensitive index to where elk populations reside relative to the quality of their range.     

Diagnostic value of gastrin for clinical bovine ostertagiosis.

Gastrin values were evaluated in 130 parasite naive calves, in 61 first season grazing calves during six field trials and in 8 experimentally infected adult immune cows. The gastrin values were linked to pepsinogen levels and daily weight gain. Also the influence of an anthelmintic treatment on pepsinogen and gastrin values was assessed during a clinical outbreak of ostertagiosis in a group of first season grazing calves. Mean gastrin levels in parasite naive calves were 106 pg/ml. Results show that a group mean of 400 pg/ml gastrin in first season grazing calves indicates a reduced daily weight gain but with no obvious clinical signs. During clinical outbreaks mean gastrin levels frequently reached 1,000 pg/ml with a severe weight loss and a mean pepsinogen level of 5,000 mU tyr. The serum gastrin concentration was strongly reduced 4 days post treatment. No gastrin response was noted following an Ostertagia challenge in adult immune cows. The value of gastrin as a diagnostic aid for ostertagiosis is discussed in relation to pepsinogen, the adult worm burden, larval inhibition and the technique involved in assessing gastrin.     

Comparative pharmacokinetic and pharmacodynamic response of single and double intraruminal doses of ivermectin and moxidectin in nematode-infected lambs

Abstract

AIMS: To compare the pharmacokinetics, distribution and efficacy (pharmacodynamic response) of intraruminal ivermectin (IVM) and moxidectin (MXD) administered at 0.2 and 0.4?mg/kg to naturally nematode-infected lambs, and to determine the ex vivo accumulation of these anthelmintics by Haemonchus contortus.

METHODS: Romney Marsh lambs, naturally infected with IVM-resistant H. contortus, were allocated to treatment groups based on faecal nematode egg counts. They received 0.2 or 0.4?mg/kg IVM or MXD (n=10 per group), or no treatment (Control; n=6), on Day 0. Samples from four animals from each treatment group, including abomasal parasites, were obtained on Day 1. Plasma samples were also collected from Day 0 to 14, and a faecal egg count reduction test (FECRT) and a controlled efficacy trial were carried out on Day 14. Concentrations of IVM and MXD in plasma, in abomasal and intestinal tissues and in H. contortus were evaluated by high-performance liquid chromatography. Additionally, the ex vivo drug accumulation of IVM and MXD by H. contortus was determined.

RESULTS: Peak plasma concentrations and the area under the concentration vs. time curve for both IVM and MXD were higher for 0.4 than 0.2?mg/kg treatments (p<0.05), but there were no differences for other parameters. Concentrations of IVM and MXD in the gastrointestinal target tissues and in H. contortus were higher compared to those measured in plasma. Concentrations of both drugs in H. contortus were correlated with those observed in the abomasal content (r=0.86; p<0.0001). The exposure of H. contortus to IVM and MXD was related to the administered dose. Mean FECRT and efficacy for removal of adult H. contortus was 0% for IVM at 0.2 and 0.4?mg/kg. For MXD, FECRT were >95% for both treatments, and efficacy against H. contortus was 85.1% and 98.1% for 0.2 and 0.4?mg/kg, respectively. The ex vivo accumulation of IVM and MXD in H. contortus was directly related to the drug concentration present in the environment and was influenced by the duration of exposure.

CONCLUSION: Administration of IVM and MXD at 0.4 compared with 0.2?mg/kg accounted for enhanced drug exposure in the target tissues, as well as higher drug concentrations within resistant nematodes. The current work is a further contribution to the evaluation of the relationship between drug efficacy and basic pharmacological issues in the presence of resistant parasite populations.     

A difference in abomasal pH between Canadian wapiti affected with chronic illthrift and unaffected deer

The pH of abomasal fluid from five purebred Canadian wapiti which were diagnosed with chronic illthrift (“fading”) was found to be elevated compared to ten clinically normal red and hybrid (wapiti × red) deer. The average abomasal pH of the affected elk was 6.3, compared to 2.5 for the unaffected red and hybrid deer.     

Isolation of Salmonella dublin from a sheep in New Zealand

Extract

On March 8, 1964, formalinized samples of liver, kidney and lung and fresh samples of mesenteric lymph nodes and lung from a ram hogget were submitted to the Wallaceville Animal Research Centre. The animal had died suddenly and post-mortem examination revealed intense reddening of the intestinal and abomasal mucosa and enlarged mesenteric lymph nodes, with some consolidation and pleural adhesions. Small red spots were observed on the liver surface. The possibility of salmonellosis was considered and appropriate cultures were made of the fresh material in addition to aerobic cultures on blood agar.     

A difference in abomasal pH between Canadian wapiti affected with chronic illthrift and unaffected deer

The pH of abomasal fluid from five purebred Canadian wapiti which were diagnosed with chronic illthrift ("fading") was found to be elevated compared to ten clinically normal red and hybrid (wapiti x red) deer. The average abomasal pH of the affected elk was 6.3, compared to 2.5 for the unaffected red and hybrid deer.     

Effects of supplemental feeding on gastrointestinal parasite infection in elk (Cervus elaphus): preliminary observations

The effects of management practices on the spread and impact of parasites and infectious diseases in wildlife and domestic animals are of increasing concern worldwide, particularly in cases where management of wild species can influence disease spill-over into domestic animals. In the Greater Yellowstone Ecosystem, USA, winter supplemental feeding of Rocky Mountain elk (Cervus elaphus) may enhance parasite and disease transmission by aggregating elk on feedgrounds. In this study, we tested the effect of supplemental feeding on gastrointestinal parasite infection in elk by comparing fecal egg/oocyst counts of fed and unfed elk. We collected fecal samples from fed and unfed elk at feedground and control sites from January to April 2006, and screened all samples for parasites. Six different parasite types were identified, and 48.7% of samples were infected with at least one parasite. Gastrointestinal (GI) nematodes (Nematoda: Strongylida), Trichuris spp., and coccidia were the most common parasites observed. For all three of these parasites, fecal egg/oocyst counts increased from January to April. Supplementally fed elk had significantly higher GI nematode egg counts than unfed elk in January and February, but significantly lower counts in April. These patterns suggest that supplemental feeding may both increase exposure and decrease susceptibility of elk to GI nematodes, resulting in differences in temporal patterns of egg shedding between fed and unfed elk.     

麋鹿重组朊蛋白单克隆抗体的制备及初步鉴定

为研制鹿慢性消耗性疾病(chronic wasting disease,CWD)单克隆抗体,本研究以原核表达后经纯化的麋鹿重组成熟朊蛋白(PrP^c)为免疫原免疫PrP^c基因敲除小鼠(PrP^c-null mice)。两次加强免疫后,利用淋巴细胞杂交瘤技术,取脾细胞与SP2/0骨髓瘤细胞进行细胞融合,间接ELISA方法筛选阳性杂交瘤细胞,采用3次有限稀释法实现杂交瘤细胞的亚克隆,筛选出5株能稳定分泌针对麋鹿重组成熟朊蛋白特异性单克隆杭体(McAbs)的杂交瘤细胞株5A5、3B2、6D12、5E3、1F5,其腹水ELISA效价均达到1∶10000以上。经鉴定,5株单抗均为IgG抗体,5A5、6D12、5E3株为IgG1亚类,3B2、1F5株为IgG2a亚类。Western blotting鉴定结果表明,获得的McAbs均能特异性识别麋鹿重组成熟朊蛋白和健康麋鹿脑组织匀浆中的PrP^c。本研究制备了CWD腹水McAbs,同时也为CWD的研究及其诊断方法的建立奠定了基础。     

Consequences of failure of the reticular groove reflex in veal calves fed milk replacer

Summary

A number of problems seen in veal calves are associated with insufficient adaptation to the changes in husbandry connected with the fattening system. These problems include chronic tympanitis, chronic vomiting, cachexia, unthriftiness, abomasal erosions and ulcers.

Some of these problems are associated with failure of the reticular groove reflex, and result in ruminal drinking.

Persistent ruminal drinking causes a syndrome characterised by a variety of symptoms such as unthriftiness, severe growth retardation, inappetence, recurrent tympany, abdomal distension, a long dry haircoat and clay‐like faeces.

Clinical studies performed to investigate the pathogenesis of the syndrome are described. It was found that the milk was stored in the rumen and was partly broken down. The presence of milk in the rumen induced typical changes in the ruminal mucosa (hyper/parakeratosis) and also inhibited casein clot formation in the abdomasum. The small intestinal mucosa showed villous atrophy. After training, the reticular groove reflex was re‐established in a number of patients but the growth rate of these calves did not return to normal.     

Liver fluke,Fasciola hepatic a in New Zealand

Extract

The common liver fluke, Fasciola hepatica, is an important cause of death and economic loss in many countries of the world. The loss can take the form of ill-thrift and consequent reduced meat, milk and wool production. Death can occur directly in severe infections or indirectly owing to black disease. Apart from this, there is the economic loss from the condemnation of infested livers for human consumption.     

Pathogens at the livestock-wildlife interface in Western Alberta: does transmission route matter?

In southwestern Alberta, interactions between beef cattle and free-ranging elk (Cervus elaphus) may provide opportunities for pathogen transmission. To assess the importance of the transmission route on the potential for interspecies transmission, we conducted a cross-sectional study on four endemic livestock pathogens with three different transmission routes: Bovine Viral Diarrhea Virus and Bovine Herpesvirus 1 (predominantly direct transmission), Mycobacterium avium subsp. paratuberculosis (MAP) (indirect fecal-oral transmission), Neospora caninum (indirect transmission with definitive host). We assessed the occurrence of these pathogens in 28 cow-calf operations exposed or non-exposed to elk, and in 10 elk herds exposed or not to cattle. We characterized the effect of species commingling as a risk factor of pathogen exposure and documented the perceived risk of pathogen transmission at this wildlife-livestock interface in the rural community. Herpesviruses found in elk were elk-specific gamma-herpesviruses unrelated to cattle viruses. Pestivirus exposure in elk could not be ascertained to be of livestock origin. Evidence of MAP circulation was found in both elk and cattle, but there was no statistical effect of the species commingling. Finally, N. caninum was more frequently detected in elk exposed to cattle and this association was still significant after adjustment for herd and sampling year clustering, and individual elk age and sex. Only indirectly transmitted pathogens co-occurred in cattle and elk, indicating the potential importance of the transmission route in assessing the risk of pathogen transmission in multi-species grazing systems.     

A syndrome of dental abnormalities of sheep: II. The pathology and radiology

Histological and radiographic examination of 23 ewe heads has revealed that mandibular osteopathy is a feature of the ovine dental abnormality syndrome described by Bruère et al.⁽³⁾ The bone changes consisted of excessive irregular remodelling of bone with osteoporosis. Developmental faults were also demon-strated. The most dramatic of these were dentigerous cysts involving unerupted permanent incisors, although malposition-ing of permanent incisors was also observed.

A histological feature of the excessive incisor wear was chronic pulpitis, perhaps a. result of the rate of wear exceeding the rate at which protective secondary dentine could be de-posited in the pulp cavity.

A number of nutritional deficiencies is known to cause gener-alised osteoporosis. Recognition of the osteopathy described here thus supports the clinical evidence of Bruère et al.⁽³⁾ that a nutritional disorder could be a major factor in the pathogenesis of this syndrome.     

Development of monoclonal antibodies against the abnormal prion protein isoform (PrPres) associated with chronic wasting disease (CWD)

Monoclonal antibodies (mAbs) specific for the abnormal prion protein isoform (PrP^res) are indispensable for diagnosing chronic wasting disease (CWD). In this study, eight mAbs were developed by immunizing PrP knockout mice with recombinant elk PrP and an immunogenic PrP peptide. The reactivity of the mAbs to recombinant PrP and the PrP peptide was measured, and their isotypes were subsequently determined. Among them, four mAbs (B85-05, B85-08, B85-12, and B77-75) were shown by Western blotting to recognize proteinase K-treated brain homogenate derived from an elk suffering from CWD.