Monoclonal Antibody-Based Dipstick Assay: A Reliable Field Applicable Technique for Diagnosis of Schistosoma mansoni Infection Using Human Serum and Urine Samples

A field applicable diagnostic technique, the dipstick assay, was evaluated for its sensitivity and specificity in diagnosing human Schistosoma mansoni infection. A monoclonal antibody (mAb) against S. mansoni adult worm tegumental antigen (AWTA) was employed in dipstick and sandwich ELISA for detection of circulating schistosome antigen (CSA) in both serum and urine samples. Based on clinical and parasitological examinations, 60 S. mansoni-infected patients, 30 patients infected with parasites other than schistosomiasis, and 30 uninfected healthy individuals were selected. The sensitivity and specificity of dipstick assay in urine samples were 86.7% and 90.0%, respectively, compared to 90.0% sensitivity and 91.7% specificity of sandwich ELISA. In serum samples, the sensitivity and specificity were 88.3% and 91.7% for dipstick assay vs. 91.7% and 95.0% for sandwich ELISA, respectively. The diagnostic efficacy of dipstick assay in urine and serum samples was 88.3% and 90.0%, while it was 90.8% and 93.3% for sandwich ELISA, respectively. The diagnostic indices of dipstick assay and ELISA either in serum or in urine were statistically comparable (P>0.05). In conclusion, the dipstick assay offers an alternative simple, rapid, non-invasive technique in detecting CSA or complement to stool examinations especially in field studies.

Fasciola gigantica: parasitological and scanning electron microscopy study of the in vitro effects of ivermectin and/or artemethea

To evaluate the in vitro effects of different, concentrations of ivermectin and/or arteinether on Fasciola giganfica worms and to study the parasitological changes and tegumental alterations using scanning electron microscopy [SEM]. F. giganhica worms were incubated in vitro for 24 and 48 hrs with 3 concentrations of either ivermectin 01. artemether [10, 20 and 50 micro g/ml] or both in half the concentration of either of them [5, 10 and 25 micro g/ml]. Exposure of Fasciola worms to 25+25 micro g/ml of combined drug regimens or to 50 micro g/ml of either ivermectin or artemether for 48 hrs led to 100%, 41.7% and 75% worm killing which were accompanied by a significant reduction in egg laying capacity and significant increase in dead eggs which were maximally recorded in combined drug regimens. SEM of the flukes incubated for 48 hrs with combined drug regimens showed maximal tegumental disruption with swelling of the worm body, roughness, blebbing, sloughing and complete loss of spines. Disruption to the tegument of the flukes induced by artemether was more than that of ivermectin. Artemether alone or combined with ivermectin in half doses had potent fasciocidal activities. Besides, half doses of combined drug regimens had higher ovicidal effects than each drug alone, in vivo studies are recommended to furtherly explore the efficacy of combined regimens against Fasciola infection

detection of Giardia lamblia coproantigen as a sensitive immunodiagnostic method for human giardiasis

This study was designed to develop a sandwich ELISA for detection of G. Iambiia antigens in stool and sera of giardiasis patients as a better diagnostic alternative to routine parasitological methods. Anti-G. Iamblia antibodies were produced by immunization of rabbit with G. lamblia antigen obtained from cultured trophozoites. Raised antibodies were then employed in sandwich ELISA for detection of G. lamblia antigen in collected sera and stool samples. In this study sera and stool samples from 80 G. lamblia infected patients, 71 patients infected with other parasites [Entamoeba histolytica, Schistosoma mansoni and Fasciola hepatica] and 30 uninfected individuals were tested by sandwich-ELISA for detection of G. lamblia antigen. The sensitivity of coproantigen assay reached 98.8% for detection of Giardia antigens in stool and 87.5% for detection of Giardia antigen in sera of giardiasis patients. The specificity of the assay was 94.1% for stool samples and 91% for sera of negative controls and patients harboring other parasites collectively. A positive correlation between age of patients and the antigen levels in both sera and stool samples of G. lamblia infected patients was observed. The sensitivity of antigen detection assay was directly related to the intensity of infection. The positivity rate for detection of coproantigen in stool was compared to the number of cysts in stool. Patients passing < 8 cysts showed false negativity in stool samples [one patient] compared to 100% positivity in patients passing > 50 cysts of stool [79 patients]. Moreover, a positive correlation was found between coproantigen level in stool and number of cysts in stool of G. lamblia infected patients [r=0.887, p< 0.001]. In conclusion, our data demonstrated that the employment of rabbit anti-G. lamblia IgG antibodies in sandwich ELISA for the detection of G. lamblia coproantigen in stool provided a sensitive and specific tool for immunodiagnosis of G. lamblia infection