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Biomedical subjects

Y Weisman

Publications and source records attributed to Y Weisman.

157 records · Page 9Linked to original sources
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Marek's disease in turkeys. II. Characterization of the viral glycoprotein B gene and antigen of a turkey strain of Marek's disease virus.

Marek's disease virus (MDV) causes immunosuppression and tumors in chickens. As sporadic cases of Marek's disease (MD) were recorded in turkeys, the antigenic and genomic characteristics of the MDV glycoprotein B (gB) gene and antigen of turkeys were compared to the chicken MDV gB. The whole chicken and turkey gB genes were sequenced and found identical. By immunoblotting of infected-cell culture lysates using chicken convalescent and gB monoclonal antibodies, the antigenic epitopes of the chicken and turkey viruses were found to differ. The turkey MDV had a unique epitope, compared to the chicken MDV and compared with our previous findings. While the chicken MDV had two epitope types, heat-labile but dithiothreitol (DTT)-stable and heat-stable but DTT-labile, the turkey MDV gB epitope is both heat and DTT-labile.

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Molecular typing of infectious bursal disease virus of Israeli field and vaccine strains by the reverse transcription/polymerase chain reaction/restriction fragment length polymorphism assay.

Infectious bursal disease viruses (IBDVs) were examined by testing bursa samples from 37 commercially reared chicken flocks and three vaccine strains by the reverse transcription (RT)/polymerase chain reaction (PCR)/restriction fragment length polymorphism assay (RFLP). The assay was conducted with a 717-bp fragment of the VP2 gene with the restriction enzymes BstNI and MboI. The presence of a restriction site for SspI was used to predict a very virulent phenotype. Results indicated the existence of two molecular groups within the field isolates; four samples showed one pattern of RFLPs, and the majority, 30 out of the 37 tested, showed a second RFLP pattern. Three samples tested negative for IBDV. Eight bursa samples, representing the two molecular groups, were also tested by the RT/PCR/RFLP assay as developed by Jackwood. A comparison of the RFLP profiles by the two methods indicated that four isolates belonged to molecular group 6 and 30 isolates belonged to a new molecular group. All field isolates had a very virulent phenotype. One vaccine strain, produced from a local isolate, was classified as molecular group 6. The other two vaccine strains had RFLPs that differed from those of the field isolates.

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Sudden death of a bearded vulture (Gypaetus barbatus) possibly caused by Newcastle disease virus.

An adult female bearded vulture (Gypaetus barbatus) in the Tel Aviv University Research Zoo was found dead without previous clinical signs. The predominant pathologic changes were considerable bloody content in the intestines and enlargement of the liver, which had a rubbery consistency with color changes. Microscopic lesions consisted of multifocal histiocytic infiltration in the liver. Newcastle disease virus (NDV) was isolated from a cloacal swab and from the lungs and liver. Intracerebral pathogenicity index of the virus, as estimated in 1-day-old chicks, was repeated three times and had an average value of 1.68, indicating a velogenic strain. Numerous Clostridium septicum bacteria were found on the intestinal surface, but bioassays in which they were orally administered into chickens and mice revealed that, even though they were heavily multiplied in the intestines, they were nonpathogenic. It seems that NDV, documented for the first time in a bearded vulture in Israel, was the likely cause of sudden death.

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Enzyme immunoassay studies on the serological response of turkeys to hemorrhagic enteritis virus.

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies in turkey serum to hemorrhagic enteritis virus. The ELISA antigen was extracted from turkey spleens and partially purified with fluorocarbon. Antibodies were demonstrated in serum samples of breeding and meat flocks that had been naturally exposed to infection. These samples were also examined in parallel by agar-gel precipitin (AGP); most of the sera were AGP-positive. ELISA, however, was more sensitive in detecting antibodies in day-old sera that were AGP-negative. The passively acquired antibodies were no longer detected by 4 weeks of age. A brisk but short-lived secondary response was detected by ELISA in the sera of turkeys immunized with beta-propiolactone-inactivated extract of infected spleens.

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Evaluation of a novel rapid kit for the visual detection of Newcastle disease virus antibodies.

A sensitive diagnostic kit for the rapid visual detection of Newcastle disease virus antibodies is described. The kit--ImmunoComb--is based on a modification of the enzymelinked immunosorbent assay and was found to be highly sensitive for detecting local immunity as well as marginal levels of humoral immunity. Therefore, it determines status of immunity and vaccine efficiency. The assay is simple and does not require special equipment or laboratory facilities. This endows the new kit with field applicability. The effectiveness and reliability of the kit were proven by a series of field experiments. Tracheal swabs and blood samples were taken from 20 flocks (chickens and turkeys) and tested by the hemagglutination-inhibition test and by the new kit. There was high correlation between the methods where the level of antibodies in the flocks ranged between negative and very high.

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Effect of tiamulin administered by various methods and dosages on turkeys at different ages.

Healthy male turkeys not receiving monensin in their feed were treated with tiamulin by various methods and at different ages. Nine cycles of treatments were performed at the ages of 26, 40, 61, 89, 103, 117, 131, 145, and 160 days. Intramuscular of subcutaneous injections of 12.5 mg/kg tiamulin up to 145 days did not result in any signs of toxicity or impair growth rate. Administration at a dose of up to 25 mg/kg, using the drinking-water-deprivation technique, caused no effect in turkeys up to 160 days (marketing age).

Administration, Oral↗
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Negative findings concerning Alcaligenes faecalis as an etiologic agent in acute respiratory disease of turkeys.

An acute respiratory disease of turkeys in Israel was first reported in November 1978. Alcaligenes faecalis was isolated from sick turkeys and from chickens not affected by the disease. Plate agglutination tests with A. faecalis antigen of 1,067 turkey and 494 chicken serum samples gave variable results: healthy turkeys gave positive reactions and sick turkeys sometimes gave negative ones. All isolated strains were highly sensitive in vitro drug sensitivity tests, but chemotherapy failed in the field. Pathogenicity trials with A. faecalis, given alone or in combination with Yucaipa virus to 8-day-old turkey poults, failed to reproduce the disease.

Alcaligenes↗
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Applications of the polymerase chain reaction to detect infectious bursal disease virus in naturally infected chickens.

Reverse transcriptase-polymerase chain reaction was used for identification of Israeli isolates of infectious bursal disease virus (IBDV). The system was applied to tissue culture and to bursa of Fabricius from infected chickens; these latter samples had been frozen for as long as 4 years. From base homology analysis of published sequences of serotype 1 IBDV, two pairs of primers, targeted to amplify sequences from the VP2 and VP3 cistrons, were prepared. The two sets of primers could detect viruses of serotype 1. The primers directed to the cistrons could detect viral sequences from seven infected chickens. No reaction was detected with RNA extracted from bursal cells of healthy chickens or from uninfected cells. The sensitivity of the reaction was equivalent to 2.5 x 10(1) TCID50.

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Efficacy of norfloxacin nicotinate treatment of broiler breeders against Haemophilus paragallinarum.

The efficacy of the antimicrobial drug norfloxacin for treating infectious coryza was examined in 26-week-old male broiler breeders. Chickens were inoculated in the infraorbital sinus with the causal organism, Haemophilus paragallinarum. Four experimental groups were set up: control uninfected chickens, infected untreated chickens, and infected chickens treated for 5 days with either 20 mg norfloxacin/kg body weight or 40 mg norfloxacin/kg body weight. The first clinical signs were seen 24 hr postinfection. Of the observed clinical signs, sinus edema was ameliorated by the treatment, and the percentage of birds presenting sinus edema, sneezing, and increased lacrimation was significantly reduced after treatment. Clinical signs disappeared rapidly and were gone by the second day of treatment. The other signs disappeared gradually over 2 weeks after treatment began. There were no significant differences between the two dosage levels. H. paragallinarum was not reisolated from the infected infraorbital sinuses of birds treated with the higher dose of the drug, whereas the reisolation rate was 17% from those treated with the lower dose and 86% from the infected untreated birds.

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Causes of losses including a Borna disease paralytic syndrome affecting young ostriches of one breeding organization over a five-year period (1989-1993).

Necropsy records and causes of mortality of ostriches up to 3 months old over a 5-year period (1989-1993) are presented. The data relate to one ostrich enterprise that comprises 10 breeding flocks, five rearing farms, and one hatchery. Causes of mortality are classified into nine major categories. The annual mortality percentages of all hatched ostriches over the 5-year period were 61%, 58%, 30%, 29%, and 16.6%, and the most significant cause of death was a paresis syndrome that accounted for 20%, 11%, 16%, 10.1%, and 2% mortality, respectively. Limb deformities and gastroenteritis were the other principal specific causes of mortality. The paresis syndrome was caused by an agent serologically related to Borna disease virus. Brain extracts from paralyzed ostriches, when given orally or intramuscularly to 5-week-old birds, reproduced the clinical signs and microscopic lesions. The mean time to death was less than 3 weeks for the intramuscularly infected group and was almost twice as long for the orally infected group.

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Avian paramyxoviruses serotype 3 isolated from captive birds in Israel: clinical signs, pathology, and antigenic characterization.

Thirteen HA agents were isolated in Israel from captive flamingoes (Phoenicopterus ruber), Egyptian geese (Alopochen aegyptiacus) belonging to order Anseriformes, and ibis (Guara rubra) belonging to order Ciconiiformes. The isolation was done from postmortem materials in three cases of severe respiratory disease with high mortality. The isolates were examined serologically and identified as belonging to the serotype 3 of avian paramyxoviruses (APMV-3). The isolates were more close antigenically to the APMV-3b variety (prototype strain--APMV-3/Parakeet/Netherlands/449/75) than to the APMV-3a variety (prototype strain--APMV-3/Turkey/Wisconsin/68). This is the first isolation of APMV-3 from birds belonging to the orders Anseriformes and Ciconiiformes.

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Isolation of avian serotype 3 paramyxoviruses from imported caged birds in Israel.

Ten avian serotype 3 paramyxoviruses were isolated for the first time in Israel from passerine and psittacine imported caged birds. The birds were submitted for investigation of an illness characterized by nonspecific signs of weakness, anorexia, vomiting, and sneezing. In addition, only the parakeets developed specific neurologic signs. In bacteriologic and pathologic investigation, cachexia and diarrhea were observed in both groups of birds. In psittacines, considerable alterations were observed in lungs, liver, and spleen. Some nonviral pathogens were occasionally isolated. The isolates appeared to belong to serotype 3b avian paramyxovirus (APMV), the prototype strain of which is APMV-3b/parakeet/Netherlands/449/75. The isolation of APMV-3 viruses from imported caged birds may represent a way of introduction of these viruses into the country.

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