Sensitivity and specificity of a new commercial enzyme-linked immunoassay kit for detecting Entamoeba histolyticaIgG antibodies in serum samples

The study presented here was conducted to evaluate the performance of the newly available RIDASCREEN Set (R-Biopharm AG, Darmstadt, Germany) for the detection of immunoglobulin G antibodies against Entamoeba histolytica. The sensitivity and specificity of this new enzyme-linked immunosorbent assay were evaluated using a panel of sera from 239 individuals. The assay was positive for 43 of 44 patients with invasive amebiasis, including all 18 patients with amebic liver abscess, while it was negative for 190 of 195 adult controls who were either healthy individuals or patients with other parasitic diseases. The kit was found to be highly specific (97.4%) and sensitive (97.7%) for detecting antibodies against E. histolytica in humans. Although antibody titers in patients with amebic liver abscess tend to be higher on average than in patients with invasive amebiasis, it is not possible to distinguish the two forms solely based on the results of this commercial test.     

The contribution of a non-invasive test to clinical care. The impact of echocardiography on diagnosis, management and patient anxiety

We prospectively studied the impact of echocardiography on a cardiologist's diagnosis and management plan and on patient anxiety for 300 consecutive referrals. There was an impact on diagnosis in 90% of patients. Most common was confirmation of diagnosis usually with the addition of information pertinent to management (81%); change of disease category or resolution of diagnostic doubt was uncommon (9%). The consultant cardiologist believed the heart to be normal in 48 patients who did not have any associated disease; none had any echocardiographic abnormality. The cardiologist reported increased diagnostic confidence in 74% of all patients but management changed in only 9%. One-third of all patients reported reduced anxiety when this was an important clinical issue but in less than half of them did the cardiologist consider that echocardiographic information was essential for reassurance. Anxiety was increased in 6%, and in 12% the anxiety response was inconsistent with the test result. The clinical contribution of the test report was most obvious for those patients (30%) in whom this data was required for (a) a decision concerning specific diagnostic or technical intervention (b) a change of management plan which implied obvious or likely health benefit (c) reassurance which was a clinically important issue. The magnitude of this contribution was related to the study indication. The value of echocardiography is obvious when assessing patients for invasive intervention or when proper treatment or adequate reassurance are impeded by diagnostic doubt. However, for many current indications, we need better definition of factors which predict a clinically useful result. In particular, when the aim is to rule-out disease, our results suggest that an expert cardiological opinion would often be more appropriate than an echocardiogram.     

Rapid test for detection of rabies antibodies in human serum.

A simple, sensitive, rapid method based on the principle of immunoadherence hemagglutination (IAHA) has been devised for the detection of rabies antibody. In this test, fixation of complement to complexes of rabies antigen with specific antibodies is readily detected by agglutination of human erythrocytes bearing receptors for C3. Sera from individuals undergoing preexposure rabies immunization were tested for rabies antibodies by the IAHA method and by a virus neutralization test performed in tissue culture, the rapid fluorescent focus inhibition test. IAHA titers showed a high degree of correlation with rapid fluorescent focus inhibition test titers, although it is not known whether results of the IAHA test represent the detection of neutralizing antibodies. An advantage of the IAHA test over the rapid fluorescent focus inhibition test was that results were obtained in a shorter period of time. In some instances, this can be of clinical significance in determining antibody levels to rabies virus. Furthermore, the IAHA test is most applicable as a rapid screening tool for the detection and quantitation of rabies antibodies in vaccinated subjects.     

Epidemiological and clinical features of travel-associated cryptosporidiosis

Data concerning the clinical and epidemiological features of travel-associated cryptosporidiosis are lacking. In order to investigate the impact of this disease on travellers' health, a retrospective study was conducted at the Institute of Tropical Medicine, Berlin. In total, 57 cryptosporidial infections were identified between 2000 and 2004, resulting in a prevalence of 2.9% in patients with travel-associated diarrhoea. Travel to south-central Asia, especially India, was associated with a higher prevalence of infection than was travel to other destinations. Clinically, the disease resembled giardiasis, but fever and arthralgias seemed to occur more frequently.