In a large study (with >36,000 participants), Tatemichi et al. clearly demonstrated an association between a low-seropositive H. pylori antibody titer and a high incidence of gastric cancer among PG-positive subjects [ 5].
The relatively low seropositive titres among veterinary staff could be explained by the lifecycle of T. gondii in the cat.
This is because of low positive predictive value of single ELISA-based assays particularly in population with low seropositive rate [ 28, 34].
A binary outcome would have led to a possible misclassification if pigs with low PRRSV IRPC values were coded as seronegative when they were, in fact, low seropositive and vice versa.
A low proportion of seropositive children was also identified in the Czech Republic (using the Vero cell neutralization test) [ 14].
The negative results for Salmonella in this screening, together with similar results in a study of 332 cervid carcasses in 1997 [ 8], suggest that cervids do not constitute a significant reservoir for human salmonellosis in Norway, although a low prevalence of seropositive moose has been reported [ 2].
In goats, on the other hand, only a low number of seropositives was found: overall 36.4%, being 16 out of 44 goats tested.
Both the lowest antibody titers and the lowest seropositive rates were detected among children <1 year of age who could not complete the primary vaccination schedule, as well as 7.1% of children <1 year of age possessed antibody against P1 only, which suggested they were exposed to type I WPV responsible for the outbreak.
Having TB resistant to at least one of the two drugs tested had an OR greater than 1 but not statistically significant (P = 0.701), while being male, below 40 years of age and HIV seropositive each had a low OR, and were not statistically significant (Table 1).
In the case of the Sm autoantigen, one of the healthy controls (1/31) was seropositive, but it was a low autoantibody titer just above the cut-off value.
