IgG Western Blot for Confirmatory Diagnosis of Equivocal Cases of Toxoplasmosis by EIA-IgG and Fluorescent Antibody Test

The performance values of available techniques used in serodiagnosis of toxoplasmosis are satisfactory but they raise problems of equivocal and discordant results for very low IgG titers. Recently marketed, LDBio-Toxo II IgG Western blot (IB) showed an excellent correlation with the dye test. We estimated the proportion of equivocal and discordant results between the enzyme immunoassay Platelia Toxo IgG (EIA-IgG) and fluorescent antibody test (FAT) and assessed the usefulness of the IB as a confirmatory test. Out of 2,136 sera collected from pregnant women, 1,644 (77.0%) tested unequivocally positive and 407 (19.0%) were negative in both EIA-IgG and FAT. The remaining 85 (4%) sera showed equivocal or discordant results. Among them, 73 (85.9%) were positive and 12 (14.1%) were negative in IB. Forty-one (89.1%) equivocal sera in EIA-IgG and 46 (86.8%) equivocal sera in FAT were positive in IB. Reducing the cut-off values of both screening techniques improved significantly their sensitivity in detecting very low IgG titers at the expense of their specificity. In conclusion, equivocal results in routine-used techniques and their discordance in determination of the immune status in pregnancy women were not uncommon. IB test appeard to be highly useful in these situations as a confirmatory technique.     

Evaluation of the presence of equine viral herpesvirus 1 (EHV-1) and equine viral herpesvirus 4 (EHV-4) DNA in stallion semen using polymerase chain reaction (PCR)

In the horse, the risk of excretion of two major equine pathogens (equine herpesvirus types 1 (EHV-1) and 4 (EHV-4)) in semen is unknown. The objective of our study was to assess the possible risks for the horizontal transmission of equine rhinopneumonitis herpesviruses via the semen and the effect of the viruses on stallion fertility.Samples of stallion semen (n = 390) were gathered from several different sources. Examination of the semen involved the detection of viral DNA using specific PCR. The mean fertility of the stallions whose sperm tested positive for viral DNA and the mean fertility of stallions whose sperm did not contain viral DNA, were compared using the Student's t-test.EHV-4 viral DNA was not detected in any of the semen samples. EHV-1 DNA was identified in 51 of the 390 samples, (13%). One hundred and eighty-two samples came from 6 studs and there was significant difference (p < 0.05) among the proportion of stallions whose semen tested positive for viral DNA from 0 to 55% between the studs.There was a significant difference (p < 0.014) between the fertility of stallions whose semen tested positive for viral DNA and those whose semen was free from viral DNA. The stallions that excreted the EHV-1 virus in their semen appeared to be more fertile than the non-excretors, but this difference was in fact related to the breeding technique since higher proportion of excretors were found among those whose semen was used fresh rather than preserved by cooling or freezing.In conclusion, this study suggests that the EHV-1 virus may be transmitted via the semen at mating or by artificial insemination as demonstrated with other herpes viruses in other species.