Biomedical subjects

J H Boon

Publications and source records attributed to J H Boon.

24 records · Page 2Linked to original sources

PubMed1984

Parasitological, serological and clinical effects of continuous graded levels of Dictyocaulus viviparus inoculations in calves.

To investigate the parasitological, serological, clinical and growth effects of continuous graded levels of Dictyocaulus viviparus inoculations in calves an experiment was carried out with 10 groups of 5 calves each. Calves were inoculated twice a week during a period of ten weeks. The range of the doses was 10-2560 infective larvae (L3) per inoculation. The results were analysed by linear and curvilinear regression of various traits on infection level. It is concluded that: A continuous exposure of calves to L3 of D. viviparus was followed by a continuous larval excretion at all levels; Results of the ELISA technique gave a very good reflection of the level of infection; Clinical signs and weight loss were evident before the parasitological and serological results were positive; The serological parameter and the parasitological parameters were mainly linearly related to the level of infection. The clinical parameters were mainly cubically related to the level of infection.

Animals↗

PubMed1984

The incidence of Dictyocaulus viviparus infections in cattle in the Netherlands. II. Survey of sera collected in the field.

Examination of nearly 2000 sera indicated that approximately 90 per cent of cattle had acquired Dictyocaulus viviparus infections during the previous grazing season. No differences were found between provinces. Large differences were seen between herds. Antibody titres of milk cows on zerograzing farms were significantly lower than on comparable farms where animals were pastured. The need for further epidemiological work is stressed. In such work serology can be helpful.

Animals↗

PubMed1983

[Lungworm disease in cattle, a persistent problem?].

From the results of a number of studies it is concluded that: (1) Cattle of a large proportion (approximately 80 per cent) of the dairy farms in the Netherlands were infected with L3 larvae of Dictyocaulus viviparus during the grazing season in 1981. (2) Experiments showed a significant negative cubic effect on the level of infection with L3 larvae of D. viviparus on the growth of calves. (3) Sporangia of Pilobolus kleinii harbouring L3 larvae were shot significantly further away than sporangia not harbouring L3 larvae.

Animals↗

PubMed1982

The incidence of Dictyocaulus viviparus infections in cattle in The Netherlands. I. The Enzyme Linked Immunosorbent Assay as a diagnostic tool.

The Enzyme Linked Immunosorbent Assay (ELISA) provides a very efficient technique for detecting antibodies against Dictyocaulus vivparus in calves. Although low level cross reactions were found in animals with gastrointestinal nematodes, the specificity and sensitivity of the technique are sufficient for herd diagnosis of lungworm infections and for survey work. This conclusion is reached on the basis of artificially and naturally infected calves. ELISA titres correlate well with Indirect Haemagglutination titres, parasitological findings, and clinical observations.

Analysis of Variance↗

PubMed1980

[Studies on the possible causes of cough in calves at pasture (author's transl)].

Respiratory disease occupies a prominent position in the series of common diseases in calves. Efforts were made to take an inventory of possible causes of cough in calves at pasture. For this purpose, a number of calves on twenty-three, ten and eight mixed farms respectively were clinically studied during the period from 1975 up to and including 1977. Faecal, sputum and serum samples were collected to examine them for the presence of husk worm larvae, husk worm eggs, antibodies to specific viruses and lung worms. In 1978, titres of antibodies to lung worms were determined in the serum samples of a large number of calves from forty-five farms. From the findings obtained, conclusions were drawn regarding the prevention of virus and lung worm infections in calves at pasture and regarding the diagnosis and prevention of verminous bronchitis in these animals.

Animals↗

PubMed1979

Operational diagnostics of lungworm infections in cattle. Preliminary investigation into the usefulness of the indirect haemagglutination.

To give an impression of the usefulness of indirect haemagglutination (IHA) in the diagnosis of lungworm infections in cattle under practical conditions, five calves vaccinated against Dictyocaulus viviparus and five unvaccinated calves were periodically subjected to clinical, parasitological, and serological examinations over a period of seven months. All calves grazed on a lungworm-infected plot. 82% of the observations in unvaccinated calves, which were positive with respect to one or more of the used parameters, concerned IHA-positive animals which, however, showed negative results with the parasitic parameters. The titre variation of the serological examination was a further indication of the fact that the IHA detected antibodies against lungworm antigens. No indications of false positive reactions were obtained. An investigation carried out on 46 farms on the correlation between serological and clinical findings on lungworm infections revealed a positive correlation in 80% of the groups between results obtained with both methods. The authors consider that IHA offers good prospects for the diagnosis of lungworm infections.

Animals↗