Comparison of two serological diagnosis tests for bovine paratuberculosis

Mycobacterium avium subsp. paratuberculosis (MAP) is the causal agent of paratuberculosis (PTBC), a chronic infectious granulomatous enteritis of ruminants. The PTBC diagnosis with commercial ELISA has limitations in sensitivity and specificity, and its results depend on the state of progress of the disease. This research aimed to evaluate two different ELISAs: (a) an "in-house" ELISA with a sonicated antigen obtained from a MAP I47 strain, and (b) a commercial ELISA. In total, the evaluated sample consisted of 394 bovine serum samples from 12 farms in Argentina with high (5-9%) and low (≤ 0.05%) prevalence of PTBC. The evaluation of the new antigen (2.5 µg/mL) was against a 1:50 dilution of the M. phlei faced sera. The cut-off point, sensitivity, and specificity determinations of both techniques were by ROC curve analysis. The area under the curve for the I47 ELISA was 0.9 (CI 95%, 0.93-0.97). With a cut-off point of 8.8%, the sensitivity was 84.3% and the specificity 96.6%. The agreement between both techniques was 0.7 (CI 95%, 0.6-0.8). These results indicate a high discriminative capacity to differentiate positive and negative bovine sera of MAP infection with the I47 ELISA. This result would represent an advantage to dispense with the imported kit.

Recurrent lacunar infarction following a previous lacunar stroke: a clinical study of 122 patients

OBJECTIVE

To determine clinical variables related to recurrent lacunar infarction following a previous lacunar stroke.

METHODS

A total of 122 out of 733 consecutive patients with lacunar infarction collected from a hospital based registry between 1986 and 2004 were readmitted because of a recurrent lacunar infarction. In a subset of 59 patients, cognition was assessed using the Mini-Mental State Examination (MMSE). Predictors of lacunar infarction recurrence were assessed by logistic regression analysis.

RESULTS

First lacunar infarction recurrence occurred in 101 patients (83%) and multiple recurrences in 21. The mean time between first ever lacunar infarction and recurrent lacunes was 58.3 months (range 2-240). In the subset of 59 patients in whom cognition was studied, cognitive impairment, defined as an MMSE score <24, was detected in 16% (8/49) of patients with first lacunar infarction recurrence and in 40% (4/10) of those with multiple lacunar infarction recurrences. In the multivariate analysis, hypertension (odds ratio 2.01, 95% CI 1.23 to 3.30) and diabetes (odds ratio 1.62, 95% CI 1.07 to 2.46) were significant predictors of lacunar stroke recurrence, whereas hyperlipidaemia was inversely associated (odds ratio 0.52, 95% CI 0.30 to 0.90).

CONCLUSIONS

Hypertension and diabetes were significant factors related to recurrent lacunar infarction. Hyperlipidaemia appeared to have a protective role. Cognitive impairment was a frequent finding in patients with multiple lacunar infarction recurrences.