Sensitivity of the standardized pseudorabies virus neutralization test varies with the test strain used.

The effect of altering the strain of the test virus used in the standardized pseudorabies virus neutralization (VN) test on the sensitivity of the assay was evaluated. Comparative VN tests were performed using 4 different strains: the avirulent Bartha parental, the avirulent recombinant Bartha gIIIKa, the moderately virulent Shope (currently used for the VN test at the National Veterinary Services Laboratory, Ames, IA), and the highly virulent P2208 (Funkhauser). A radioimmunoassay and a Western immunoblotting technique were employed to verify the presence of anti-pseudorabies virus (PrV) antibodies in sera. Statistical analysis indicated that replacement of the Shope strain by the Bartha gIIIKa or the P2208 strain resulted in VN titers that were 4.23- and 2.00-fold higher, respectively. Despite these differences, specificity with regard to PrV diagnosis was unaltered. This apparent enhancement of the sensitivity of the PrV VN test would be beneficial for the serologic identification of PrV-infected animals during an eradication effort.     

Thyroid function in the cat: assessment by the TRH response test and the thyrotrophin stimulation test

Changes in total thyroxine (T4), free T4 and total tri-iodothyronine (T3) were measured in 13 cats after the intravenous injection of varying doses of thyrotrophin stimulating hormone (TSH) (0–5 U/cat n = 6; 1 U/cat n = 8; 1 U/kg bodyweight, n = 7) or thyrotrophin releasing hormone (TRH) (100 ug/cat, n = 10). All three doses of TSH resulted in a significant (P < 0–05) rise in T4, free T4 and T3 levels, with the mean peak in hormone concentrations occurring six to eight hours after injection. The three doses of TSH all appeared to produce maximal stimulation of thyroid hormone secretion. The mean percentage increase in hormone concentrations at seven hours following the three doses of TSH ranged from 167 to 198 per cent for T4, 240 to 365 per cent for free T4, and 73 to 116 per cent for T3. Following administration of TRH there was also a significant (P < 0–05) rise in T4, and free T4. The mean peak in T4 and free T4 levels occurred at four hours, and mean increases in hormone levels at this time were 92 per cent for T4, and 198 per cent for free T4. The administration of TRH produced little change in T3 levels. TSH administration resulted in a significantly higher (P < 0–05) percentage peak increase in T4, free T4 and T3 levels at all three dosages than did TRH.     

Value of the antiglobulin test and indirect immunofluorescence test in the serological diagnosis of bovine brucellosis]

In investigations of 5881 sera from brucella infected herds and 8635 sera from negative herds the antiglobulin test (AgT) because of its high susceptibility was shown to be a valuable method in early diagnosis of brucellosis and clearing of non-specific LA-reactions. However, all infected animals are not detected with the AgT. Therefore it is not adaptable to use in selection controlling, also in combination with other methods. In the final steps of the eradication measures against bovine brucellosis the AgT offers a very valuable serological complementary method. The indirect fluorescence test has no diagnostical advantages in comparison with the AgT and is not recommended for practical brucellosis serology.     

Serological investigation of Corynebacterium pseudotuberculosis infection in sheep--correlation between the hemolysis inhibition test and the ELISA test

Corynebacterium pseudotuberculosis causes caseous lymphadenitis in sheep and goats. The animals may be infected without showing clinical symptoms. Several serotests have therefore been employed to detect infected animals. Shen et al (1982) performed an enzyme linked immunosorbent assay (ELISA) to detect antibodies against the organism using cell wall antigens. Maki et al (1985) found that the toxin of the bacterium was a better antigen for assessing infection in the ELISA test. They reported that the antitoxin ELISA appeared to be as sensitive as the antihemolysin inhibition test (Zaki 1968).     

The IBR-IPV virus-serum neutralization test. Sensitivity and significance of the tissue culture tube test

A modification of the IBR-IPV virus-serum neutralization test (tissue culture tube test) was used in examinations of three groups of cattle: animals at AI centres; selected herds from infected districts; and pregnant cows and heifers from all over the country. In, respectively, 141 samples out of 1335, 215 out of 344, and 46 out of 7928, a virus-neutralizing effect was demonstrated. Within the three groups of samples, respectively, 2.8 %, 29.4 %, and 28.3 % of samples positive by the modified test were negative by the conventional test, even with undiluted serum. The findings gave strong evidence that all positive reactions were results of a preceding infection. All animals with a history of infection responded serologically when examined by the modified test, but still the distribution of the titers recorded in herd examinations indicates the desirability of a further improvement in the sensitivity of the test.     

Evaluation of the dermatophyte test medium RapidVet-D

The performance of the dermatophyte test medium (DTM) RapidVet-D was assessed using hair samples collected from experimentally infected guinea pigs. Three dermatophyte species were included in the study: Microsporum canis , Trichophyton mentagrophytes and Trichophyton equinum . DTM substrates were inoculated with infected hairs and scales, incubated at 18, 21, 24, 27 or 37 °C and examined daily for 15 days. The rapidity of colour change was clearly related to the incubation temperature and to the number of infected hairs deposited on the reactive substrates. With the optimum incubation temperature 27 °C, a systematic colour change could be observed only a few days post-inoculation: 3 days with M. canis infected hairs, 4 days with T. equinum and 5 days with T. mentagrophytes .