Isolation from ducks of a hypervirulent strain of duck plague virus and an avian type 6 paramyxovirus

This paper describes the isolation and identification of a duck plague virus (DP) and a paramyxovirus (PMV₆), from the livers and intestines collected in 4-month old mule ducks, under fattening, exhibiting 75% mortality and necrotic-haemorrhagic gross lesions. These viruses were isolated in specific pathogen free (SPF) muscovy duck eggs and SPF chicken eggs respectively. Then the DP virus was adapted to duck and chicken fibroblasts. The disease was reproduced in 2-week old SPF muscovy ducklings, intramuscularly inoculated with the previous organs, as well as in contact ducks. From them, only the DP virus was isolated again. Experimentally the intramuscular inoculation of the duck plague French vaccinal strain, 4 h post contact, did not prevent the disease and did not decrease its severity.

Regarding the DP virus, the typical signs and lesions observed in experimentally infected muscovy ducks as well as the presence of intranuclear inclusions of the epithelial cells of their oesophagus, intestines, bursa of Fabricus and liver on the one hand, and on the other hand, of the epithelial cells of the duck egg chorio-allantoïc membrane and fibroblasts inoculated with the samples first defined, allowed the characterization of the virus. Direct electron microscopy, as well as the results of seroneutralization tests with different specific avian Herpes virus antisera confirmed the DP virus identification. Moreover the DP isolate was not antigenically different from the serotype actually known.

The haemagglutinating virus (PMV₆) was characterized by direct electron microscopy as well as with 18 specific avian Myxovirus antisera; its identification was confirmed too by the specific seroconversion observed 4 weeks post-inoculation of this virus, in 11 weeks old SPF muscovy ducklings.

Finally an assay was carried out to appreciate the pathogenicity of theses viruses inoculated either separately or associated. It showed the high pathogenicity of the DP strain. The PMV₆ was apathogenic and no synergic effect with the DP virus was demonstrated. It appears to be the first isolation of PMV₆ in France, to our knowledge. The epidemiological circumstances related to theses isolations are discussed. The failure of the emergency vaccination in contact ducks, might be attributed to the high virulence of the DP strain.     

Efficacy of transsphenoidal hypophysectomy in treatment of dogs with pituitary-dependent hyperadrenocorticism

The long-term survival, disease-free fractions, and the complications of hypophysectomy in 150 dogs with pituitary-dependent hyperadrenocorticism (PDH) were examined in a prospective study. Long-term survival and disease-free fractions in relation to pituitary size were analyzed by the Kaplan-Meijer estimate procedure. The 1-, 2-, 3-, and 4-year estimated survival rates were 84% (95% confidence interval [CI], 76-89%), 76% (67-83%), 72% (62-79%), and 68% (55-77%), respectively. Treatment failures included procedure-related mortalities (12 dogs) and incomplete hypophysectomies (9 dogs). The 1-, 2-, 3-, and 4-year estimated relapse-free fractions were 88% (CI: 80-93%), 75% (64-83%), 66% (54-76%), and 58% (45-70%), respectively. Postoperative reduction of tear production (58 eyes in 47 dogs) was often reversible but remained low until death in 11 eyes of 10 dogs. Central diabetes insipidus (CDI) occurred more frequently (62%) in dogs with enlarged pituitaries than in dogs with nonenlarged pituitaries (44%). Survival and disease-free fractions after hypophysectomy were markedly higher in dogs with nonenlarged pituitaries than in dogs with enlarged pituitaries. Transsphenoidal hypophysectomy is an effective treatment for PDH in dogs. The survival and disease-free fractions after hypophysectomy decrease and the incidence of CDI increases with increasing pituitary size. Therefore, early diagnosis of PDH is important and transsphenoidal hypophysectomy is expected to have the best outcome when used as primary treatment for dogs with nonenlarged or moderately enlarged pituitaries.     

A treatment study of canine symmetrical onychomadesis (symmetrical lupoid onychodystrophy) comparing fish oil and cyclosporine supplementation in addition to a diet rich in omega-3 fatty acids

Background

Treatment of symmetrical onychomadesis (symmetrical lupoid onychodystrophy) is a challenging task for dermatologists. The acute phase is characterized by sloughing of claw plates and loose claws have to be removed and secondary infections treated. The goal of long-term treatment is to allow claws to re-grow with normal quality and to achieve life-long lack of recurrence. The aim of this randomized treatment trial was to see if adding fish oil or cyclosporine to a diet rich in omega-3 could improve the treatment outcome of symmetrical onychomadesis in Gordon and English setters. All dogs were fed Eukanuba Veterinary Diets Dermatosis® exclusively during the six month treatment trial. The treatment outcome was measured as the change in number of healthy claws during treatment, as well as the long-term effect on hunting ability and recurrence of onychomadesis. The hypothesis was that cyclosporine provides a stronger and different immune modulating property than fish oil and therefore would give a better treatment outcome in dogs with symmetrical onychomadesis eating a diet rich in omega-3 fatty acids.

Results

Six Gordon setters and one English setter were treated with 5 mg/kg cyclosporine once daily for six months and seven Gordon setters were treated with 10 ml Dr Baddaky fish oil® once daily for six months. All dogs were evaluated every month and the numbers of healthy claws were recorded.There was a statistically significant improvement in the number of healthy claws after six months of treatment with a median increase of 13.5 claws for both groups. However, there was no statistically significant difference between the two treatment groups regarding the improvement in number of healthy claws, as assessed using the Wilcoxon rank-sum test (P = 0.15). Dogs in the cyclosporine group had a median increase of 10 healthy claws after six months of treatment while the median for the fish oil group was 14. Long-term cure was not achieved with either treatment.

Conclusion

Cyclosporine and fish oil appeared to be equally effective in treating symmetrical onychomadesis when the dog is fed a diet high in omega-3.     

Fetal protection against bovine viral diarrhoea type 1 virus infection after one administration of a live-attenuated vaccine

A modified-live vaccine has been shown previously to prevent fetal infection with bovine viral diarrhoea virus (BVDV)-2 and, to some extent BVDV-1, when used in association with an inactivated vaccine in a two-step vaccination protocol. In this challenge study, the modified-live vaccine used alone was able to protect 13 heifers between 49 and 96 days of gestation at challenge from leucopenia and virus replication and, for a 4-month period, to prevent fetal infection. The efficacy of the BVDV-1f 22146/Han81 challenge was demonstrated by virus isolation from the fetuses of all nine non-vaccinated, control heifers. However, the small number of heifers tested meant that the vaccination failure rate could be as high as 10% in the field.     

Drug use and antimicrobial resistance among Escherichia coli and Enterococcus spp. isolates from chicken and turkey flocks slaughtered in Quebec,Canada

An observational study was conducted of chicken and turkey flocks slaughtered at federal processing plants in the province of Quebec, Canada. The objectives were to estimate prevalence of drug use at hatchery and on farm and to identify antimicrobial resistance (AMR) in cecal Escherichia coli and Enterococcus spp. isolates and factors associated with AMR. Eighty-two chicken flocks and 59 turkey flocks were sampled. At the hatchery, the most used antimicrobial was ceftiofur in chickens (76% of flocks) and spectinomycin in turkeys (42% of flocks). Virginiamycin was the antimicrobial most frequently added to the feed in both chicken and turkey flocks. At least 1 E. coli isolate resistant to third-generation cephalosporins was present in all chicken flocks and in a third of turkey flocks. Resistance to tetracycline, streptomycin, and sulfisoxazole was detected in > 90% of flocks for E. coli isolates. Antimicrobial resistance (AMR) was observed to bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, and tetracycline in both chicken and turkey flocks for Enterococcus spp. isolates. No resistance to vancomycin was observed. The use of ceftiofur at hatchery was significantly associated with the proportion of ceftiofur-resistant E. coli isolates in chicken flocks. In turkey flocks, ceftiofur resistance was more frequent when turkeys were placed on litter previously used by chickens. Associations between drug use and resistance were observed with tetracycline (turkey) in E. coli isolates and with bacitracin (chicken and turkey), gentamicin (turkey), and tylosin (chicken) in Enterococcus spp. isolates. Further studies are needed to provide producers and veterinarians with alternative management practices and tools in order to reduce the use of antimicrobial feed additives in poultry.     

Influence of adjuvant formulation on the induced protection of mice immunized with total soluble antigen of Trichinella spiralis

Vaccination of pigs against the helminth nematode Trichinella could be a good alternative to prevent the risk of human infection. In order to develop an efficient and safe vaccine, the choice of the adjuvant is an important issue. In this study, two adjuvants were selected to prepare vaccines based on total soluble Trichinella spiralis muscle larvae (ML) antigen: Montanide ISA 70 water in oil emulsion and Montanide IMS nanoparticles. Aluminium hydroxide was used as a reference adjuvant. The immune response was checked by ELISA of parasite antigen specific IgG1 and IgE. Finally, protection induced in vaccinated mice was measured after a T. spiralis challenge by counting ML burdens. The results clearly showed an impact of adjuvants on the specific IgG1 and IgE antibody responses against T. spiralis. Differences were observed between the rates of protection induced according to the type of formulation, although the three adjuvants tested were able to enhance the humoral immune response. This work demonstrated the need to use an adjuvant to obtain a specific IgG1 and IgE responses directed against the total soluble extract of T. spiralis.     

Congenital Tremor With Spongy Degeneration of the Central Nervous System in Two Puppies

Two crossbred puppies exhibited a generalized tremor that was accentuated by excitement or voluntary movement. Hypermetria was also present. Neurohistologic examination showed a bilaterally symmetric spongy condition, predominantly of the gray matter in the brain and spinal cord. These two dogs were different, both in their clinical presentation and histologic appearance, from other reported cases of spongy degeneration. The clinicopathologic correlation between spongy degeneration and tremor is unclear. Spongy degeneration should be included in the differential diagnosis of tremor syndromes in puppies.     

Regulation of lysine metabolism and endosperm protein synthesis by the opaque-5 and opaque-7 maize mutations

Two high lysine maize endosperm mutations, opaque-5 (o5) and opaque-7 (o7), were biochemically characterized for endosperm protein synthesis and lysine metabolism in immature seeds. Albumins, globulins, and glutelins, which have a high content of lysine, were shown to be increased in the mutants, whereas zeins, which contain trace concentrations of lysine, were reduced in relation to the wild-type lines B77xB79+ and B37+. These alterations in the storage protein fraction distribution possibly explain the increased concentration of lysine in the two mutants. Using two-dimensional polyacrylamide gel electrophoresis of proteins of mature grains, variable amounts of zein polypeptides were detected and considerable differences were noted between the four lines studied. The analysis of the enzymes involved in lysine metabolism indicated that both mutants have reduced lysine catabolism when compared to their respective wild types, thus allowing more lysine to be available for storage protein synthesis.     

Phylogeny of five predominant pospiviroid species in Belgium

In Belgium pospiviroids are routinely detected in various hosts. The most frequently found pospiviroids are: Citrus exocortis viroid (CEVd), Chrysanthemum stunt viroid (CSVd), Potato spindle tuber viroid (PSTVd), Tomato apical stunt viroid (TASVd) and Tomato chlorotic dwarf viroid (TCDVd). Apart from the high incidence of pospiviroids in latently-infected ornamentals, viroids have also been found in plants where they cause disease: PSTVd and TCDVd in tomatoes and CSVd in chrysanthemum. In order to gain more epidemiological data on these infections, this study has conducted phylogenetic analyses of Belgian isolates for each of these five pospiviroid species. PSTVd and CEVd-isolates show a clustering depending on host plant identity. This was not observed for TCDVd and TASVd. A very high degree of sequence similarity was noticeable for CSVd-isolates from various hosts. During the past decade, PSTVd and CSVd-infected mother plants have been systematically eradicated in Belgium after positive detection results, also when found in symptomless plants, leading to a decreased trend of these quarantine pests in the past few years. However, other non-quarantine pospiviroid species are still ubiquitously present in many ornamentals. Since these pospiviroids can be equally harmful to crops as the two quarantine pests PSTVd and CSVd, there is still a risk that transmission occurs from symptomless-infected ornamental plants to economically important crops in Belgium such as tomato, pepper and chrysanthemum.