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1.
The efficacy of eprinomectin on Dictyocaulus filaria and Cystocaulus ocreatus in naturally infected sheep was evaluated in the present study. In total, 30 infected sheep were randomly divided into two groups: treated (n?=?15) and untreated (n?=?15). A single pour-on dose of eprinomectin (0.5?mg/kg) was administered to the treated group. No medication was used in the untreated group. Faecal larval counts were performed on pre-treatment (day 0) and post-treatment (days 7, 14, 21 and 42) days. Eprinomectin was found to be 100% effective against D. filaria on day 7 post-treatment when compared with the untreated group and it maintained this effect on days 14, 21 and 42. However, the decrease in faecal larval count of C. ocreatus was found to be 86, 86 and 91%, on days 14, 21 and 42, respectively.  相似文献   

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The results of analysis of phospholipids (PL) and fatty acid content in the blood of sheep infected with the nematodes Dictyocaulus filaria are displayed. A significant increase of lysophosphatidylcholine and arachidonic acid as well as a decrease of docozagexaenic acid in PL of infected sheep have been recorded. That points out to structural and functional disorders of cellular membranes during the infection. These disorder could be used as a metabolic criterion to estimate the relationships within the host-parasite system examined.  相似文献   

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Alterations in the sheep erythrocyte membrane constituents during the course of Dictyocaulus filaria infection were studied in 4–6 month old Nali lambs. During the acute course of infection, plasma cholesterol, membrane cholesterol, cholesterol: phospholipid ratio and acetylcholinesterase activity fell significantly when compared with uninfected controls. The onset of the fall in the values of these parameters was observed 1–2 weeks prior to an increase in the osmotic fragility of erythrocytes. The altered values persistently remained at sub-normal levels during the chronic stage of the infection. However, the membrane proteins and phospholipids of sheep erythrocytes remained unaffected during the entire period of study. The clinico-parasitological picture of the disease, as judged by the clinical course of disease, faecal larval output and necropsy worm recovery, was typical of ovine dictyocauliosis.  相似文献   

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C-banding has been performed on Dictyocaulus filaria using both original and modified techniques. The karyotype is reported based on C band observations. The existence of large heterochromatic blocks appears to be the cause of the low chiasmata frequency.  相似文献   

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The bionomics of the free-living larvae of Dictyocaulus filaria on pasture, and the transmission of infection between lambs, were studied during different seasons of the year in North-East England. The rate of development of first-stage larvae to the third stage took 4-9 days in late spring and summer, 1 1/2-4 weeks in autumn and 5 1/2-7 weeks in winter. The proportion of first-stage larvae developing to the third stage ranged from 10-28% in autumn and winter, and 2-25% in spring and summer. The rate of mortality of the third-stage larvae was approximately logarithmic in nature, although the survival time was shorter in spring and summer than in autumn and winter. Third stage larvae were able to survive from autumn until the spring of the following year in sufficient numbers to perpetuate transmission but not to cause clinical disease. In a transmission study, the survival of the infective larvae on the experimental plot was poor in summer, but the larval population increased in the autumn and then declined slowly throughout the winter. Infection in the susceptible lambs was related to the level of infection on the herbage increasing in severity from early summer to late autumn. However, those lambs infected in the summer were resistant to the heavy autumn challenge of larvae on pasture.  相似文献   

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The influence of Coxsackie B4 and AI3 viruses on the pancreas of mice (resistant and susceptible to diabetes) was studied. Glucose intolerance and changes in the synthesis of immunoreactive insulin were detected in all the treated groups of animals. Biochemical changes were more prominent in male DBA/2 mice, infected with Coxsackie B4 virus, in FI (CBA X C57Bl/6) hybrids and in female DBA/2 mice infected with Coxsackie AI3 virus and alloxan.  相似文献   

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The serologic and cell-mediated immune responses of hamsters exposed to 2 strains of Entamoeba histolytica (HM-1 and HM-19) were evaluated by a series of in vitro tests. The pathogenicity of the 2 strains was evaluated in terms of their ability to produce liver abscesses and spleen enlargement. Antibody response was evaluated by the indirect hemagglutination test. The cellular immune response was assayed by increased DNA synthesis by lymphocytes and migration inhibition of macrophages.  相似文献   

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Background

The variability in the clinical or pathological presentation of transmissible spongiform encephalopathies (TSEs) in sheep, such as scrapie and bovine spongiform encephalopathy (BSE), has been attributed to prion protein genotype, strain, breed, clinical duration, dose, route and type of inoculum and the age at infection. The study aimed to describe the clinical signs in sheep infected with the BSE agent throughout its clinical course to determine whether the clinical signs were as variable as described for classical scrapie in sheep. The clinical signs were compared to BSE-negative sheep to assess if disease-specific clinical markers exist.

Results

Forty-seven (34%) of 139 sheep, which comprised 123 challenged sheep and 16 undosed controls, were positive for BSE. Affected sheep belonged to five different breeds and three different genotypes (ARQ/ARQ, VRQ/VRQ and AHQ/AHQ). None of the controls or BSE exposed sheep with ARR alleles were positive. Pruritus was present in 41 (87%) BSE positive sheep; the remaining six were judged to be pre-clinically infected. Testing of the response to scratching along the dorsum of a sheep proved to be a good indicator of clinical disease with a test sensitivity of 85% and specificity of 98% and usually coincided with weight loss. Clinical signs that were displayed significantly earlier in BSE positive cases compared to negative cases were behavioural changes, pruritic behaviour, a positive scratch test, alopecia, skin lesions, teeth grinding, tremor, ataxia, loss of weight and loss of body condition. The frequency and severity of each specific clinical sign usually increased with the progression of disease over a period of 16–20 weeks.

Conclusion

Our results suggest that BSE in sheep presents with relatively uniform clinical signs, with pruritus of increased severity and abnormalities in behaviour or movement as the disease progressed. Based on the studied sheep, these clinical features appear to be independent of breed, affected genotype, dose, route of inoculation and whether BSE was passed into sheep from cattle or from other sheep, suggesting that the clinical phenotype of BSE is influenced by the TSE strain more than by other factors. The clinical phenotype of BSE in the genotypes and breed studied was indistinguishable from that described for classical scrapie cases.  相似文献   

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Background

Sickle cell anemia is caused by a single type of mutation, a homozygous A→T substitution in the ß globin gene. Clinical severity is diverse, partially due to additional, disease-modifying genetic factors. We are studying one such modifier locus, HMIP (HBS1L-MYB intergenic polymorphism, chromosome 6q23.3). Working with a genetically admixed patient population, we have encountered the necessity to generate haplotype signatures of genetic markers to label genomic fragments with distinct genealogical origin at this locus. With the goal to generate haplotype signatures from patients experimentally, we have investigated the suitability of an existing nanofluidic assay platform to perform phase alignment with single-nucleotide polymorphism alleles.

Methodology/Principal Findings

Patient DNA samples were loaded onto Fluidigm Digital Arrays and individual DNA molecules were assayed with allele-specific probes for SNP markers. Here we present data showing the utility of the nanofluidic approach, yielding haplotype data identical to those obtained with a family-based method. We then determined haplotype composition in a group of patients with sickle cell disease, including in those where a mathematical inference approach gave ambiguous or misleading results. Experimental phasing of genotypes across 3.8 kb for rs9399137, rs9402685, and rs11759553 created unequivocal haplotype signatures for each of the patients. In 68 patients, we found 8 copies of a haplotype signature (‘C-C-T’), which is known to be prevalent in Europeans but to be absent in West African populations. We have confirmed the identity of our phased allele pairs by single-molecule sequencing and have demonstrated, in principle, that three-allele phasing (using three colors) is a potential extension to this method.

Conclusions/Significance

Phased haplotypes yield more information than the individual marker genotypes. Procedures such as the one described here would therefore benefit genetic mapping and functional studies as well as diagnostic procedures where the identity or parental origin of short genetic fragments is of importance.  相似文献   

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