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Biomedical subjects

J H van Eck

Publications and source records attributed to J H van Eck.

At least 19 recordsLinked to original sources
PubMed2004

A serological survey for pathogens in old fancy chicken breeds in central and eastern part of The Netherlands.

To get an impression of the presence of pathogens in multi-aged flocks of old fancy chicken breeds in the Netherlands, plasma samples originating from 24 flocks were examined for antibodies against 17 chicken pathogens. These flocks were housed mainly in the centre and east of the Netherlands, regions with a high poultry density. The owners of the tested flocks showed their chicken at national and international poultry exhibitions. Antibodies against Avian Influenza, Egg Drop Syndrome '76 virus, Pox virus, Salmonella pullorum/gallinarum, Salmonella Enteritidis or Salmonella Typhimurium were not detected. However, antibodies against other Salmonella species, Mycoplasma gallisepticum, infectious bursal disease virus, infectious bronchitis virus, avian encephalomyelitis virus, chicken anaemia virus, infectious laryngotracheitis virus, and avian leukosis virus, subgroups A and B, and subgroup J were detected in a varying proportion of the flocks. This study shows that antibodies against many chicken pathogens are present among the flocks of old fancy chicken breeds that are exhibited at international poultry exhibitions.

Animals↗
PubMed1990

Protection of broilers against Newcastle disease by hyperimmunisation of the dams.

A flock of broiler parents was hyperimmunised against Newcastle disease (ND) by subcutaneous injection of an experimental high-potency inactivated oil emulsion (IOE) vaccine in order to achieve high and long-lasting passive protection in broilers. During the egg production period mean log2 HI ND titre of the parents slowly decreased from 11.6 at 26 weeks of age to 10.0 at 53 weeks of age. Titres of day-old progeny paralleled those of their parents. Mean protection of broilers against mortality following challenge with Herts 33 virus at the ages of 1, 2, 3 and 4 weeks was 86%, 73%, 54% and 44%, respectively. As compared with the current Dutch situation, application of the high-potency IOE vaccine will significantly increase antibody titres in parent flocks and the level and duration of passive protection in broilers. It is concluded that passive ND protection of broilers by hyperimmunisation of the dams is realisable from an economic point of view and is suitable for low-risk areas.

Animals↗
PubMed1987

Comparison of the effect of live Newcastle disease vaccine Clone 30 in broilers administered at day 1 or at day 7 and the effect of H120 vaccination at 17 days of age: a field experiment.

To analyse the results of a vaccination on the first day of age against Newcastle disease (ND) and on the 17th day of age against Infectious Bronchitis (IB) resp. with spray vaccines with Clone 30 and H120 vaccine. These vaccinations are compared in field circumstances with other vaccination methods. A serological examination and challenge test were used to be informed about the response and protection. From the present study the following conclusions can be drawn: Clear indications are obtained that following a spray vaccination against ND with Clone 30 vaccine of one-day-old broilers which possessed maternal antibodies, birds received a moderately good protection against ND, in spite of very low levels of HI antibodies. A spray vaccination against IB with H120 vaccine of broilers at 17 days of age gave some protection from two weeks after vaccination, however making a good conclusion about the protection is impossible and further investigation is required.

Animals↗
PubMed1987

Immunity to Newcastle disease in fowl of different breeds, primarily vaccinated with commercial inactivated oil-emulsion vaccines: a laboratory experiment.

Fowl were primarily vaccinated with commercial inactivated oil emulsion (IOE) Newcastle disease (ND) vaccines and immunity was established by both determination of haemagglutination inhibiting (HI) antibodies and by challenge, over periods similar to the economic life span of the birds. The effect of level of maternal antibodies, route of vaccine administration, and vaccine dose on the vaccination results were studied. In one experiment, immunity provoked by vaccination with IOE vaccine was compared with that obtained by vaccination with live vaccines. Vaccination by the subcutaneous route induced a significantly stronger HI response than intramuscular vaccination. Also the vaccine dose per bird and the level of maternal antibodies influenced the vaccination results. In both brown layer and White Leghorn (WL) hens a strong immunity was induced up to at least 45 and 78 weeks of age respectively, by vaccination with IOE vaccine at 6 weeks of age. Also WL hens primarily vaccinated with IOE vaccine at 70 weeks of age, responded with high levels of HI antibodies, which persisted for at least 39 weeks. However, immunity in meat type fowl vaccinated at 6 weeks of age was poor. Following subcutaneous vaccination of one-day-old broilers with high maternal antibody titres with one dose of IOE vaccine per bird, immunity during the fattening period was at an insignificantly lower level than in birds vaccinated with live vaccine at 7 days of age. Twofold vaccination with IOE vaccine at one day old and 18 weeks of age of meat type fowl with high maternal antibody titres provoked a moderate immunity up to at least 55 weeks of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Involvement of spleen components of mature fowl in the primary and secondary humoral antibody response following experimental EDS'76 virus infection.

Cellular changes in spleens of mature fowl in relation to both the primary and secondary humoral antibody response following experimental EDS'76 virus infection were studied. The influence of splenectomy on humoral antibody response was also examined. Experimental fowl had been naturally infected with fowl adenovirus (FAV) but did not possess precipitins to these viruses at the time of EDS'76 virus infection. Since EDS'76 infection provokes a recall of the group antibody to FAV, this infection simultaneously induces a primary response against EDS'76 virus and a secondary response due to the recall of the group antibody to FAV. HI and precipitating antibody to EDS'76 virus (primary response) were first detected at 6 and 8 days p.i. respectively. Curves of HI, precipitating and neutralising antibody titres were biphasic; the first peak (IgM peak) occurred at 10-11 days p.i., the second (IgG peak) at 16-28 days p.i. Precipitating antibodies to FAV (secondary response) were demonstrated from 4 days p.i. The curve of these antibody titres was also biphasic, with peaks at the same times as in the primary response. Based on HI and AGP testing of primary and secondary immune response in both splenectomised and non-splenectomised fowl it is concluded that in the primary response the spleen of the adult fowl is involved significantly in only IgM secretion, while in the secondary response it is likely that both IgM and IgG are secreted in considerable amounts. Clusters of lymphoblasts and plasmablasts were observed at 3 days p.i. in the red pulp. It is very likely that antigen-antibody complexes are formed from that time and circulate bound to the surface of lymphocytes. These antigen-loaded lymphocytes are 'picked up' from the blood stream by -red pulp macrophages, leading to enhanced formation of lymphoblasts in the red pulp. Great numbers of these cells (which are very probably IgM secreting cells) were present on days 6 and 7 p.i., but were no longer detectable after day 10 p.i. -macrophages of the macrophagal ellipsoidal corona (MEC), leading to significant enlargement of the periellipsoidal lymphoid tissue (PELT) by an increase of the number of lymphocytes observed from days 4-12 p.i. The MEC was significantly enlarged from 7-12 days p.i., very likely due to an increased number of macrophages. Following deposition of antigen in the white pulp, formation of follicles begins. The number of small, intact follicles including follicle precursors increased from 6 days p.i.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenoviridae Infections↗
PubMed1984

Biochemical changes in blood and uterine fluid of fowl following experimental EDS'76 virus infection.

The pH, pCO2, and pO2 values and the concentrations of sodium, potassium, calcium, magnesium, chloride, phosphorus, bicarbonate, base excess, protein, glucose, as well as the activity of alkaline phosphatase and malate dehydrogenase were determined in the venous blood and uterine fluid of control and EDS'76 virus-infected fowl. Moreover, the pH of the mucosa of different parts of the oviduct was measured. Hens were examined in the period from 10 to 24 days following infection; blood and uterine fluid samples were collected approximately 14 hours after oviposition, provided a plumped egg was present in the uterus. Examination of blood and pH measurement of oviduct mucosa did not yield significant differences between infected and noninfected hens. In comparison with noninfected control birds, the mean sodium concentration of the uterine fluid of infected hens producing soft shelled or shell-less eggs had evidently increased, while the mean concentration of potassium, calcium, magnesium and glucose had decreased. Similar differences were also observed between infected hens producing normally shelled eggs and infected hens producing abnormally shelled eggs. No significant differences between infected and not infected hens were observed concerning the other values determined in the uterine fluid. It is concluded that functional disturbances which account for shell aberrations following EDS'76 virus infection are located in the surface epithelial cells of the uterine mucosa. These disturbances are very probably initiated by a depressed function of the sodium pump. All changes observed in the uterine fluid of infected hens could be explained by this depressed function.

Adenoviridae Infections↗
PubMed1982

Serological examination and egg production of progeny of fowl experimentally infected with egg drop syndrome 1976 virus.

Following EDS'76 virus (BC14 virus) infection of breeder chickens by the conjunctival route, vertical transmission occurred in the first week after infection. In the progeny which had been infected with EDS'76 virus by the vertical route, increasing haemagglutination inhibiting (HI) titres to BC14 virus and increasing numbers of birds with HI titres were observed from 3 weeks to 15 weeks of age. Sixty-one per cent of the hens and 77 per cent of the cocks had 2 log HI BC14 virus titres exceeding 4 at an age of 15 weeks. Some birds which han been serologically negative throughout the rearing period, seroconverted between 25 and 28 weeks of age. This phenomenon occurred in hens as well as in cocks. Simulation of stress twice during the laying period by injection of corticosteroid hormone did not increase the number of birds serologically positive to EDS'76 virus. EDS'76 was observed in the group of hens that was vertically infected, since egg production was significantly depressed between 28 and 34 weeks of age. Probably this was mainly the results of a production drop in the hens showing serconversion at 27 or 28 weeks of age. In this group of fowl vertically infected with EDs'76 virus, serologically positive birds appeared to be protected for the greater part to BC14 virus challenge at 50 weeks of age, while negative birds seemed to be fully susceptible. Chicks hatched from eggs collected in the third and fourth week after infection of the dams had maternal antibodies. Fertility and hatchability of apparently normally shelled eggs seemed not to be affected after BC14 virus infection of the dams. Intensive contact with contaminated faeces is probably an indispensable condition for lateral transmission of the virus.

Adenoviridae Infections↗
PubMed1981

Incidence of EDS'76 virus infection in fowl in 1980 in the Netherlands in comparison with the incidence in 1976-1978.

Serological examinations demonstrated that Egg Drop Syndrome 1976 (EDS'76) virus infection was of no significance in the Dutch poultry industry in 1980, in contrast to the situation in 1976-1978 when this infection was of widespread occurrence. The conclusion was reached that the sharp decrease in the incidence of EDS'76 virus infection was due to large scale vaccination in 1978 and 1979. The results of this study show that there is no further need for general EDS'76 vaccinations. However, continuous serological monitoring is necessary to detect flocks for which vaccination is indicated.

Adenoviridae Infections↗
PubMed1980

Egg transmission of egg drop syndrome 1976 virus in fowl.

Egg transmission of egg drop syndrome 1976 virus (BC14 virus) in fowl was demonstrated in the second and third week after experimental infection. Eggs of BC14 virus infected hens were incubated weekly after disinfection with formaline gas. After 18 days of incubation, eggs with live embryos were homogenized. This egg material was fed to adult hens, housed in isolators. Seroconversion in these birds demonstrated egg transmission. It is suggested that egg transmission occurs as a result of viremia.

Adenoviridae Infections↗
PubMed1980

[Disease and depressed egg production in turkeys resulting from the use of a semen diluent contaminated by bacteria (author's transl)].

A report on acute disease and irreversible depression of egg production in turkeys associated with considerable economic losses, probably due to bacterial contamination of the semen diluent. The disease was almost completely reproduced experimentally using remainders of this semen diluent and a suspension of bacteria isolated from the diluent. On post-mortem examination, active ovaries, chronic peritonitis, residues of yolk in the abdomen and inflammation of the infundibulum were observed. In view of the presence of pathological changes in this portion of the oviduct, the depressed egg production was probably due to impairment of function of the infundibulum.

Animals↗
PubMed1980

Egg production in relation to the results of a long term serological survey of 73 flocks of fowl.

Seventy-three flocks of fowl were tested at regular intervals for the presence of precipitins to fowl adenovirus (AV) and infectious bronchitis virus (IBV), haemaggluinating inhibiting antibodies to BC in 14 virus, and of agglutinins to Mycoplasma gallisepticum (M.g.) and Mycoplasma synoviae (M.s.). In all the eight flocks affected with Egg Drop Syndrome (EDS '76), egg production problems were associated with increasing numbers of BC14 virus reactors and AV reactors. In flocks showing production problems other than EDS'73 without any apparent cause, the average percentage of AV reactors increased significantly after the rearing period; this was not true of IBV reactors. BC14 reactors were either absent or present only once, in small numbers and with low titres, during the test period. The average percentage of AV reactors did not increase after the rearing period either in normally producing flocks or in flocks with production problems for which other diseases or dietary errors plausibly accounted for these problems. All this suggests a pathogenic role of AV in production problems. One can conclude from the high percentage of reactors in all groups of flocks that subclinical IBV infections are common. The percentage of IBV reactors during the laying period of flocks with EDS'76 was significantly higher than that of normally producing flocks. It is therefore suggested that subclinical IBV infection could be among the factors causing stress, acting as a trigger for EDS'76. All M.g.-infected flocks showed production problems; M.s. infections could not be related to egg production disturbances.

Animals↗