Possibilities and limits of immunodiagnosis of strongyle infections in horses

In an investigation period over 8 months the natural course of infection was studied by means of coproscopic and serological methods in 27 mares and 29 foals. The examination of the stool showed in mares, before the beginning of the grazing season, an infection rate of 100% with small and a rate of 7.4% with large strongyles (Str. vulgaris). Serologically the ELISA showed in foals only a distinct increase of antibody activity with the somatic antigen. The mares retained the high IgG-values of activity, which were already found at the beginning of the investigations. Even though the agglutination test can be applied for control of the effectiveness of therapy in a horse population, individual diagnostic possibilities remain limited. This is due to the reduced sensitivity and specificity of the IgG(T)-concentration under natural conditions of infection. The double-antibody-sandwich-ELISA technique has shown to be basically feasible as a test for antigens from small strongyles. Somatic antigen could most sensitively be demonstrated by antibodies to ES-antigen, ES-antigen, however, by antibodies against somatic antigens.     

SYSTEMATIC TESTING OF QUALITY IN GRASS VARIETIES

The degree of precision obtained In the quality testing of grass varieties under two systems of management was examined (1) in a single cut, (2) under a system of proportionate bulking of produce from individual cuts during a season, and (3) after pooling two seasons' data from two centres.
Crude protein, crude fibre, soluble carbohydrate, and in vitro digestible dry matter were determined. The components of variance were analysed and in the data from single cuts varietal differences in digestibility of 2.10 were significant (P=0.05). Using data from two seasons at two centres, a high degree of precision was obtained for all attributes in a grazing management system and varietal differences in digestibility of 1.25% were significant.
Variation due to location and season was greater in hay cuts taken 10 days after ear emergence. In both systems varieties differed more in soluble carbohydrate content than in the other chemical components.     

Improving the specificity of immunodiagnosis for porcine brucellosis

This report describes the use of cell mediated immunity to improve specificity of current diagnosis for Brucella suis. Diagnosis is problematic due to cross reactions that lead to false positive serological reactions (FPSR) in the standard diagnostic tests. A common cause of this cross reactivity is infection with the organism Yersinia enterocolitica O:9. Gottingen™ mini-pigs were experimentally infected with B. suis biovar I field strain or Y. enterocolitica serotype O:9 biotype 3. Infection was followed for 70 days. During this time whole blood stimulation assays were set up using Brucella specific antigen. IFNγ was measured in the supernatants (SN) from these assays by ELISA. Concurrent standard serological tests were carried out. The results indicate that the IFNγ assay is specifically able to distinguish Y. enterocolitica O:9 infection from a B. suis infection in experimentally infected mini-pigs. These results represent an improvement in diagnostic specificity compared to currently used serological tests. Thus suggesting that in a surveillance setting this test could be applied as a confirmatory test in the face of FPSR. The authors are British Civil Servants and as such their work is subject to British Crown Copyright. This means the exclusive copyright for the article cannot be transferred.     

Pregnancy diagnosis in cows with linear‐array real‐time ultrasound scanning: A preliminary note

Summary

Pregnancy diagnoses were performed under farm conditions in 201 cows (Hungarian Red Pied and crosbreds with Holstein) between 21 and 70 days after last insemination date, using a linear‐array real‐time ultrasound scanner with a 3.0 MHz rectal tranducer. Identification of (a) sharply demarcated black area(s) and/or an embryo within the uterus were used as criterions for pregnancy.

Pregnancy was confirmed by rectal examination at 6 and/or 8 weeks after A.I. From the total number of correct positive diagnoses (n= 129), incorrect positivediagnoses (n = 3, made on days 36,40 and 44 after A I), correct negative diagnoses (n =62) and incorrect negativediagnoses (n = 7, made on days 25, 28, 28, 29, 30, 31, and 33 after A I). a sensitivity of 94.8%, a specificity of 95,3%, a positive predictive value of 97.7% and a negative predictive value of 89.8% were calculated.

From these preliminary results it was concluded that real‐time ultrasound scanning is a useful and reliable technique for early pregnancy diagnosis in cows. It is suggested that a combination of milk/plasma progesterone estimation between days 21 and 24 and real‐time ultrasound scanning between days 25 and 45 would allow the confirmation and quantification of (late) embryonic mortality in the cow.     

Varying infectivity ofTaenia taeniaeformis for rats and mice

Strains ofTaenia taeniaeformis were shown to possess markedly differing infectivities for Sprague-Dawley rats and CF1 mice. Strains from Scotland, Belgium and Iraq were more infective for mice than rats while this situation was reversed with a Malaysian strain. There were also differences in their ability to infect hosts of different ages within the range 3–12 weeks of age.