Prion protein gene polymorphisms in pedigree sheep in Ireland

The development of clinical signs of scrapie in sheep has been linked to polymorphisms in the prion protein (PrP) gene. The most important polymorphisms appear to be at codons 136, 154 and 171. The objective of this study was to investigate polymorphisms at these codons in five native (Belclare, Galway, Wicklow Cheviot, Donegal Blackface Mountain and Mayo Blackface Mountain) and five imported (Texel, Bleu du Maine, Rouge de l'Ouest, Vendéen and Charollais) sheep breeds in Ireland. A total of 13 genotypes were found. The percentage of the most resistant genotype AA(136)RR(154)RR(171)varied from 1.8 per cent in the Vendéen breed, 3.1 per cent in Donegal Blackface Mountain, 10.0 per cent in Texel, 11.1 per cent in Wicklow Cheviot, 12.9 per cent in Belclare, 22.0 per cent in Charollais, 25.6 per cent in Mayo Blackface Mountain, 33.3 per cent in Galway, 46.4 per cent in Bleu du Maine to 62.5 per cent in Rouge de l'Ouest. The results indicate that a significant amount of variation exists between the breeds analysed in this study.     

Tolerance of a rice-based oral rehydration solution given to normal calves

The objective of the study was to test the tolerance of a rice-based oral rehydration formula when fed to calves. Six healthy Holstein calves, 1 week of age, were fed the formula instead of milk replacer for 3 days. Pre- and posttreatment results of clinical examination and laboratory parameters were compared. Vital signs, attitude, appetite, clinical hydration status, urine specific gravity, and most routine serum biochemistry test results did not vary and remained within the normal range. Five of the 6 calves developed diarrhea when fed the rice-based formula, which was accompanied by a reduction in fecal pH and presence of reducing sugars in the feces. This effect was reversed when calves were returned to the milk replacer diet at the end of the study. Diarrhea was accompanied by increased water consumption, which allowed the calves to maintain normal hydration status. These results suggest that calves are unable to properly digest the rice-derived carbohydrate, and this type of formula is not recommended for oral rehydration of calves.     

Effect of daily floor treatment with sodium bisulfate on the fly population of horse stalls

OBJECTIVE: To determine application rate and effectiveness of sodium bisulfate to decrease the fly population in a horse barn environment. SAMPLE POPULATION: 12 privately owned farms in southeastern Pennsylvania. PROCEDURE: Application rates of sodium bisulfate were approximately 2.3 kg/stall, 1.1 kg/stall, and 0.5 kg/stall. Two or 3 stalls were treated, and 1 or 2 stalls were not treated (control stalls) at each farm. Farm personnel applied sodium bisulfate in treated stalls daily for 7 days. Fly tapes were hung from the same site in treated and control stalls. After 24 hours, the fly tape was removed, flies adhering to the sticky surface were counted and recorded, and a new fly tape was hung. This procedure was repeated daily during each of the testing periods. RESULTS: Following the application of 2.3 kg of sodium bisulfate/stall, the numbers of flies collected on the fly tape were significantly decreased in treated stalls, compared with control stalls during the same time periods on 9 of the 12 farms evaluated. Following the application of 1.1 kg of sodium bisulfate/stall, fly numbers were significantly decreased in treated stalls on 6 of the 9 farms evaluated. Following the application of 0.5 kg of sodium bisulfate/stall, fly numbers were significantly decreased in the treated stalls on 3 of the 4 farms evaluated. CONCLUSIONS AND CLINICAL RELEVANCE: Our findings suggest that sodium bisulfate would be effective for fly control in horse barns.     

Pneumothorax in horses: 40 cases (1980-1997)

OBJECTIVE: To characterize pneumothorax in horses and to describe clinical signs, diagnostic testing, and clinical outcome of horses with pneumothorax. DESIGN: Retrospective study. ANIMALS: 40 horses. PROCEDURE: Medical records of horses with pneumothorax were reviewed to obtain information on signalment, history, clinical signs, diagnostic testing, treatment, and clinical outcome. RESULTS: Horses developed pneumothorax secondary to pleuropneumonia (17 horses), open wounds of the thorax (9), closed trauma to the thorax (7), surgery on the upper portion of the respiratory tract (3), and surgery involving the thoracic cavity (1); 3 horses had pneumothorax of unknown cause. Clinical signs included tachypnea, dyspnea, cyanosis, lack of lung sounds on auscultation of the dorsal aspect of the thorax, fever, tachycardia, signs of depression or anxiousness, and cough. Radiography and ultrasonography were useful to definitively diagnose pneumothorax. Pneumothorax was bilateral in 47.5% (19/40) and unilateral in 42.5% (17/40) of horses; designation of unilateral versus bilateral was not recorded in the remaining 4 horses. Horses with pneumothorax secondary to pleuropneumonia more commonly had unilateral pneumothorax (64.7% for unilateral vs 29.4% for bilateral; not specified for 1 horse). Horses with pneumothorax secondary to pleuropneumonia were less likely to survive than horses with pneumothorax secondary to other causes (35.3 vs 69.6% survived, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Pleuropneumonia is an important cause of pneumothorax in horses. Classic clinical signs of pneumothorax may not be evident. Radiography, ultrasonography, or both may be required for diagnosis. Prognosis for survival is better for horses with pneumothorax not associated with pleuropneumonia.     

Quantitative real-time PCR for detection of neurotoxin genes of Clostridium botulinum types A,B and C in equine samples

Botulism in horses in the USA is attributed to Clostridium botulinum types A, B or C. In this study, a duplex quantitative real-time PCR (qPCR) for detection of the neurotoxin genes of C. botulinum types A and B, and a singleplex qPCR for detection of the neurotoxin gene of C. botulinum type C, were optimized and validated for equine gastrointestinal, faecal and feed samples. The performance of these assays was evaluated and compared to the standard mouse bioassay (MBA) using 148 well-characterized samples, most of which were acquired from a repository of veterinary diagnostic samples from cases of botulism: 106 samples positive for C. botulinum (25 type A, 27 type B, 28 type C, 1 type D and 25 type E) and 42 negative samples. The sensitivities of the qPCR assays were 89%, 86% and 96% for C. botulinum types A, B and C, respectively. The overall sensitivity of the mouse bioassay for types A, B and C was 81%. The specificities of the qPCR assays were 99–100% and the specificity of the mouse bioassay was 95%.     

Orchestration of the DNA-damage response by the RNF8 ubiquitin ligase

Cells respond to DNA double-strand breaks by recruiting factors such as the DNA-damage mediator protein MDC1, the p53-binding protein 1 (53BP1), and the breast cancer susceptibility protein BRCA1 to sites of damaged DNA. Here, we reveal that the ubiquitin ligase RNF8 mediates ubiquitin conjugation and 53BP1 and BRCA1 focal accumulation at sites of DNA lesions. Moreover, we establish that MDC1 recruits RNF8 through phosphodependent interactions between the RNF8 forkhead-associated domain and motifs in MDC1 that are phosphorylated by the DNA-damage activated protein kinase ataxia telangiectasia mutated (ATM). We also show that depletion of the E2 enzyme UBC13 impairs 53BP1 recruitment to sites of damage, which suggests that it cooperates with RNF8. Finally, we reveal that RNF8 promotes the G2/M DNA damage checkpoint and resistance to ionizing radiation. These results demonstrate how the DNA-damage response is orchestrated by ATM-dependent phosphorylation of MDC1 and RNF8-mediated ubiquitination.     

IHHN Virus as an Etiological Factor in Runt-Deformity Syndrome (RDS) of Juvenile Penaeus vannamei Cultured in Hawaii

Runtdeformity syndrome (RDS) is an economically significant, frequent disease problem of cultured Penaeus vannamei . RDS is characterized by variable, often greatly reduced, growth rate of up to 30% of a cultured population and many shrimp with cuticle deformities of the rostrum, anterior appendages or other parts. The cause of RDS is undetermined.
Nursery trials comparing histologically IHHN-positive and histologically IHHN-negative Penaeus vannamei cultured under identical conditions were conducted at The Oceanic Institute. The IHHN-positive populations developed RDS symptoms including increased individual size variation, reduced population growth, and high prevalance of rostrum, antennae or cuticle deformity, while the IHHN-negative groups displayed none of these symptoms. No other diseases or parasites were identified in the IHHN-positive populations that would account for the RDS symptoms.
A single commercialele nursery was stocked with histologidly IHHN-positive P. vannamei and a high prevalence of RDS was observed. Shrimp growth was bimodal with a subpopulation growing normally and a subpopulation growing slowly. Significant relationships between shrimp harvest size and IHHN prevalance, selected individual organ IHHN severity grades and IHHN severity index (six organs evaluated) were found. Large, apparently normal shrimp were less severely infected with virus and did not display any cuticle deformities.
In sum, these data provide epidemiological and histopathological evidence for the hypothesis that infection by IHHN virus is the cause of RDS in cultured P. vannamei .