The role of the bursa of Fabricius in the immune response to vaccinal antigens and the development of immune tolerance in chicks (Gallus domesticus) vaccinated at a very young age.

Vaccination is recognized to be the most cost-effective means of preventing, controlling, and even eradicating infectious diseases. Conventional poultry are vaccinated through various routes including eye/nose drops, drinking water, vent brush, or injection. Efficient vaccination is an essential part of any good poultry management.The bursa of Fabricius is intimately connected to the cloaca and the intestinal system. It is well-known as a primary lymphoid organ in the chicken and a major channel through which environmental antigens stimulate the immune system. In this study we tested whether direct instillation of various viral vaccines and antigens into the cloaca (per bursam), could stimulate higher antibody titers and generate improved protection. Despite the very rapid absorption of the vaccines or antigens from the cloaca to the lumen of the Bursa of Fabricius, per bursam inoculation failed to generate a satisfactory immune response. In contrast conventional administration of live or inactivated commercial vaccines led to an acceptable level of seroconversion and protection against challenge.An interesting finding in this study was the fact that administration of a single priming dose of antigenic material at age 1 or 5 days, did not improve the response to a second administration at 14 days of age as expected. Instead, in most cases there was a reduced serum antibody response suggesting the induction of tolerance. This was true for all routes of administration (intramuscular, per ocular and per bursam) and for all formulations of vaccine.The current study reveals: 1) no advantage for direct application of live or inactivated vaccines or antigens into the bursa of Fabricius compared to common routes of vaccination, 2) that apparent desensitization or tolerance effects have important implications for poultry management, since in many countries, vaccination of day old chicks is compulsory or a well-accepted part of flock vaccination.According to our results, early vaccination can in fact reduce or inhibit a secondary immune response to subsequent vaccination and increase susceptibility to disease agents.

Recombinant egg drop syndrome subunit vaccine offers an alternative to virus propagation in duck eggs.

Egg drop syndrome (EDS) virus vaccines are routinely produced in embryonated duck eggs (Solyom et al., 1982). This procedure poses the risk of dissemination of pathogens, such as avian influenza virus, as the eggs used are not from specific pathogen free birds. To address this problem, the knob and part of the shaft domain of the fibre protein of the EDS virus (termed knob-s) were expressed in Escherichia coli and assessed as a subunit vaccine. A single vaccination with the recombinant protein induced the production of anti-EDS virus antibodies, as detected by haemagglutination inhibition, enzyme-linked immunosorbent assay and virus neutralization tests, for at least 20 weeks. A positive correlation was demonstrated between these three assays. A dose-response assessment showed that the vaccine was effective over the range of 2 to 64 microg protein per dose. Two vaccinations with the recombinant protein, administered before the onset of lay, induced high haemagglutination inhibition antibody titres, comparable with those induced by an inactivated whole-virus vaccine. The vaccine did not have any adverse effects on egg production, quality or weight. The present study has shown that two vaccinations with the recombinant knob-s protein elicited high neutralizing antibody titres that persisted for more than 50 weeks of lay.

Chicken infectious anemia virus infection in Israeli commercial flocks: virus amplification, clinical signs, performance, and antibody status.

The impact of chicken infectious anemia virus (CIAV) infection on commercial chicken flocks in Israel was examined by analyzing flocks with or without typical CIAV signs, signs of other diseases, or apparently healthy flocks. In 23 flocks (broilers and layers) of ages up to 8 wk, typical signs of CIAV infection (stunting, gangrenous dermatitis, and secondary bacterial infections) were recorded. When permitted by flock owners, in several cases among these 23 flocks the morbidity, mortality, and performance parameters were recorded; the presence of CIAV was detected by polymerase chain reaction (PCR); and the antibody status of parents and broilers was measured. In addition, total mortality, number of birds sold, total kilograms of meat sold, density (kg/m2), mean age at slaughter, daily growth rate in grams, total kilogram of food consumed, food conversion rate, and the European Index were calculated. We also surveyed flocks affected by other diseases, such as tumors, respiratory diseases, or coccidiosis, and flocks with no apparent clinical signs. The latter flocks were negative by CIAV-PCR, indicating that typical CIAV clinical signs are associated with one-step PCR-CIAV amplification. However, a small amount of CIAV might still be present in these flocks, acting to induce the subclinical effects of CIAV infection. These data indicate a link between the presence of virus sequences and typical CIAV signs and strengthen the concept that CIAV infection has a negative economic impact on the chicken industry.

Detection of peanut allergens in breast milk of lactating women.

CONTEXT: Most individuals who react to peanuts do so on their first known exposure. A potential but unproven route of occult exposure resulting in sensitization to peanut is via breast milk during lactation. OBJECTIVE: To investigate the ability of maternal dietary peanut protein to pass into breast milk during lactation. DESIGN AND SETTING: Clinical investigation conducted at 2 North American hospitals from March 1999 to October 2000. PATIENTS: Twenty-three healthy, lactating women aged 21 to 35 years. INTERVENTION: Each woman consumed 50 g of dry roasted peanuts, after which breast milk samples were collected at hourly intervals. MAIN OUTCOME MEASURES: Presence in breast milk of total peanut protein, analyzed by a sandwich enzyme-linked immunosorbent assay, and 2 major peanut allergens, Ara h 1 and Ara h 2, detected by immunoblot analysis. RESULTS: Peanut protein was detected in 11 of 23 subjects. It was detected in 10 subjects within 2 hours of ingestion and in 1 subject within 6 hours. The median peak peanut protein concentration in breast milk was 200 ng/mL (mean, 222 ng/mL; range, 120-430 ng/mL). Both major peanut allergens Ara h 1 and Ara h 2 were detected. CONCLUSIONS: Peanut protein is secreted into breast milk of lactating women following maternal dietary ingestion. Exposure to peanut protein during breastfeeding is a route of occult exposure that may result in sensitization of at-risk infants.

Molecular cloning of a novel human gene encoding a 63-kDa protein and its sublocalization within the 11q13 locus.

A human cDNA previously isolated by virtue of its ability to complement partially the ultraviolet sensitivity of a xeroderma pigmentosum cell line was further characterized. The transcription unit is expressed as a single 4.0-kb mRNA that encodes a novel 63-kDa cytoplasmic protein, possibly initiating from an internal AUG codon. The gene encoding this protein, named UVRAG, has been extremely well conserved during evolution, implying an important role for this gene product in cell metabolism. The transcribed mRNA is constitutively expressed in a wide variety of human tissues. The protein encoded by this gene is predicted to contain a coiled-coil structure and is likely to be metabolically unstable based on the occurrence of a strong PEST domain. UVRAG was assigned to human chromosome 11 by Southern hybridization to a somatic cell hybrid panel. Fluorescence in situ hybridization coupled with PCR analysis of human/rodent somatic cell hybrids containing segments of human chromosome 11 has localized this gene to a subregion of 11q13 in between the D11S916 and the D11S906 loci. Importantly, this region has been shown to be amplified in a variety of human malignancies, including breast cancer.

Effects of the accidental feeding of lasalocid sodium to broiler breeder chickens.

Lasalocid sodium was accidentally introduced into the feed of several broiler breeder chicken farms at levels between 115 and 150 ppm. On one farm, leg weakness and ataxia were observed in a few cockerels. A reduction in egg production and a sharp decrease in fertility and hatchability were observed in all the flocks receiving the contaminated feed. Many piping chicks were unable to hatch and there was an increase in the number of weak ataxic chicks at the hatchery. Histological examination of the muscle tissues of the affected cockerels, the piping chicks unable to hatch and the one-day-old chicks with leg weakness and ataxia revealed severe muscle damage. Increasing levels of lasalocid were detected in the yolk of eggs collected from the affected flocks.

Use of azole compounds for the treatment of experimental aspergillosis in turkeys.

A model for aspergillosis by injecting fungal spores into the lung is described. The model permits evaluation of anti-mycotic agents and their effect on the development of lesions in the infected lung, the spreading to the second lung and other organs. The therapeutic effect of the azole compounds enilconazole, ketoconazole, itraconazole and levamisole was determined. Itraconazole was found to be the most effective.

Zygomycosis in ostriches.

An unusual disease characterized by anorexia, progressive stunting and stomach impaction was observed in young ostriches after treatment with antibiotics. The massive accumulation of a clear white gelatinous mucus adherent to the inner surface of the ventriculus plus a severe necrosis of the glandular layer were the only consistent findings. Histological examination revealed typical forms of a zygomycete invading the affected tissue. The zygomycete Rhizopus oryzae was isolated from the ventriculus of all the affected ostriches.

Aspergillosis in ostriches.

A severe case of aspergillosis was observed in a flock of 3- to 8-week-old ostriches at a farm in Israel. A. niger and A. flavus were isolated from the lungs of affected ostriches. A heavy contamination with both fungi was detected in the hatchery, suggesting a brooder borne infection. The clinical and pathological findings observed in this case are described.

An unusual Clostridium colinum infection in broiler chickens.

An unusual syndrome has been observed during the past two years in flocks of 12- to 25-day-old broiler chickens in Israel. The disease is characterized by enterotoxaemic-like signs including a high and sudden mortality, apathy, severe localized enteritis and nephrosis. C. colinum which is the causal agent of ulcerative enteritis has been the only bacteria consistently isolated from the affected chickens. The clinical and pathological findings in this syndrome are different from those reported for ulcerative enteritis.

Effect of water restriction on renal function in ostriches (Struthio camelus).

The production of a white urine by ostriches can be indicative of illness or water deprivation. A metabolic renal study was carried out by dehydrating young, healthy ostriches for 2 days, the period during which urine was still excreted. It was found that the normally copious colourless urine changed to a thick, white excretion after 2 days dehydration and no fluid was excreted after 3 days. From the blood and urine analyses it is concluded that the ostrich conserves body water by an excellent renal concentrating mechanism which excretes urates. This excretion is a useful sign to the fanner that for some reason the animals are not drinking, be it due to a lack of drinking water or to illness.

Vaccination of young turkeys against fowl cholera.

Turkey poults vaccinated at one day of age with commercial inactivated Pasteurella multocida (PM) bacterin responded with low titres of antibody (ab) as measured by ELISA, but had an acceptable degree of resistance when challenged with the X-73 strain of PM until 13 weeks of age. Turkeys vaccinated at 3 and/or 6 weeks of age responded with higher ab titres and were resistant to virulent challenge with PM. Turkey poults vaccinated at 3 and/or 6 weeks of age with a commercial live PM vaccine had a poor immune response and low resistance to virulent challenge. When live PM vaccine was given to turkey poults previously vaccinated with an oil-emulsion PM bacterin, the turkey poults were highly resistant to virulent challenge, although the booster vaccination did not always induce a significant increase in the ab titres. The ELISA test used did not appear to be adequate for evaluation of the degree of protection induced in turkey flocks vaccinated at a very young age.

Reference blood chemical values in ostriches (Struthio camelus).

Reference blood chemical values were determined for 65 male and 61 female ostriches (Struthio camelus) 1 month to 72 months of age. Plasma values of glucose, total protein, triglycerides, cholesterol, uric acid, urea, bilirubin, creatinine, osmolality, electrolytes, and enzyme activity were determined. In general, differences in various values appeared mainly among age groups and less so between sexes. Older ostriches had lower plasma glucose values and enzyme activity than did younger ostriches. High plasma sodium and chloride concentrations in young ostriches correlated with high plasma osmolalities. Plasma calcium values were lower in laying ostriches. Uric acid concentrations were markedly higher than were urea concentrations in all ostriches.

Newcastle disease in ostriches (Struthio camelus): field case and experimental infection.

An outbreak of Newcastle disease (ND) in ostriches is described. In a flock aged 5 to 9 months of age 13 out of 46 ostriches died, whereas a neighbouring flock of 11-month-old birds remained unaffected. The main clinical signs were nervous. Hemagglutination inhibition (HI) titres reached log(2) 8. The virus was isolated from the brain only. Experimental infection of five, 3-month-old ostriches with virulent ND virus caused the death of three birds within 5 to 10 d. Another had to be killed after showing typical signs. HI titres after 5 days exceeded log(2) 5. The virus could be reisolated from different organs.

Haematological parameters of the otrich (Struthio camelus).

Haematological reference values according to age and sex, were obtained from healthy ostriches (Struthio camelus) held under intensive conditions. Erythrocytic parameters and indices demonstrated an age-related trend: the packed cell volume, haemoglobin concentration and erythrocyte count were lowest in ostriches of 1 to 3 months of age. The mean corpuscular volume increased with age until adulthood. No sex-linked differences were demonstrated in regard to the erythrocytic parameters. Leukocyte counts were higher in younger ostriches; changes also being detected in the differential count with age. The erythrocyte sedimentation rate was both sex- and age-related. Young birds had the fastest rate of sedimentation and females had a faster rate than males.

Parsley-induced photosensitivity in ostriches and ducks.

Clinical and pathological changes suggesting an acute case of photo-sensitivity were observed in a flock of ostriches. A preliminary diagnosis of parsley (Petroselinum sativum)-induced photosensitisation was confirmed by experimental reproduction of the typical lesions in ducks. This seems to be the first report on natural and experimental induction of photosensitivity in ostriches and ducks caused by the ingestion of parsley.

Pox in ostriches.

Clinical signs suggesting pox were observed in a flock of ostrich chicks (Struthio camelus), 10 to 60 days old. The disease was confirmed by isolation of the agent from affected ostriches and reproduction of typical pox lesions in turkeys. Further infection of young ostriches was prevented by vaccination with fowl pox vaccine.

Clinical and pathological changes caused by the interaction of lasalocid and chloramphenicol in broiler chickens.

Uncommon and abnormal gait, characterised by toe walking and progressive leg weakness, was observed in a large broiler flock in Israel. Identical clinical signs were reproduced when young chicks received feed supplemented with lasalocid (Abatec-Roche), and chloramphenicol at normal recommended levels, for 12 days or more. The clinical and pathological findings suggest a neuromuscular toxic effect of lasalocid-chloramphenicol interaction in broiler chicks. To our best knowledge this is the first report on the toxic effect caused by the combination of lasalocid and chloramphenicol.