Use of enzyme-linked immunosorbent assay and dipstick assay for detection of Strongyloides stercoralis infection in humans.

A homemade enzyme-linked immunosorbent assay (ELISA) (Academic Medical Center ELISA [AMC-ELISA]) and a dipstick assay for the detection of anti-Strongyloides stercoralis antibodies in serum were developed and evaluated together with two commercially available ELISAs (IVD-ELISA [IVD Research, Inc.] and Bordier-ELISA [Bordier Affinity Products SA]) for their use in the serodiagnosis of imported strongyloidiasis. Both commercially available ELISAs have not been evaluated previously. The sensitivities of the assays were evaluated using sera from 90 patients with parasitologically proven intestinal strongyloidiasis and from 9 patients with clinical larva currens. The sensitivities of the AMC-ELISA, dipstick assay, IVD-ELISA, and Bordier-ELISA were 93, 91, 89, and 83%, respectively, for intestinal strongyloidiasis. In all tests, eight of nine sera from patients with larva currens were positive. The specificity was assessed using a large serum bank of 220 sera from patients with various parasitic, bacterial, viral, and fungal infectious diseases; sera containing autoimmune antibodies; and sera from healthy blood donors. The specificities of AMC-ELISA, dipstick assay, IVD-ELISA, and Bordier-ELISA were 95.0, 97.7, 97.2, and 97.2%, respectively. Our data suggest that all four assays are sensitive and specific tests for the diagnosis of both intestinal and cutaneous strongyloidiasis.

Reliable serodiagnosis of imported cystic echinococcosis with a commercial indirect hemagglutination assay.

A commercially available indirect hemagglutination assay (IHA) (Echinococcosis Fumouze; Laboratoires Fumouze, Levallois-Perret, France) was evaluated using sera from 52 patients with proven cystic echinococcosis. The specificity was assessed using 247 sera from patients with various parasitic, bacterial, viral, and fungal infectious diseases; sera containing autoimmune antibodies; and sera from healthy blood donors. With a cutoff value for a positive result of 320 (as recommended by the manufacturer), the sensitivity and specificity were 88% and 98.4%; with a cutoff of 160, the sensitivity and specificity were 94% and 95.1%, respectively. The IHA is rapid, easy to perform, and is a very sensitive serodiagnostic test for cystic echinococcosis.

Use of rapid dipstick and latex agglutination tests and enzyme-linked immunosorbent assay for serodiagnosis of amebic liver abscess, amebic Colitis, and Entamoeba histolytica Cyst Passage.

A homemade enzyme-linked immunosorbent assay (ELISA) and a dipstick assay (Dipstick) for the detection of anti-Entamoeba histolytica antibodies in serum were developed and evaluated together with a commercially available latex agglutination test (LAT; Laboratoires Fumouze) for their use in serodiagnosis of amebiasis. The sensitivity of these assays was evaluated with sera from 27 patients with radiologically proven, cellulose acetate precipitation (CAP) test-positive amebic liver abscess, 7 patients with parasitologically and PCR-proven amebic colitis, and 11 patients with parasitologically and PCR-proven E. histolytica cyst passage. The sensitivities of the ELISA, Dipstick, and LAT were all 93.3% (42/45). With a combination of Dipstick and LAT, all abscess and colitis patients had at least one positive result. The specificity was assessed with 238 sera from patients with various parasitic, bacterial, viral, and fungal infectious diseases, sera containing autoimmune antibodies, and sera from healthy blood donors. The specificities of the ELISA, Dipstick, and LAT were 97.1%, 98.1%, and 99.5%, respectively. Of 61 sera from patients with PCR-proven E. dispar infection, 60 (98.4%) were negative in both Dipstick and LAT and 59 (96.7%) were negative in ELISA. Our data suggest that all three assays are sensitive serological tests. The rapid LAT and Dipstick provide fast results and can easily be applied in routine laboratories in order to facilitate the diagnosis of amebiasis.

Value of diagnostic techniques for cutaneous leishmaniasis.

BACKGROUND: Traditional diagnostic tests, ie, smear, culture, and histopathology of a skin biopsy specimen, are not always conclusive in patients with a clinical diagnosis of cutaneous leishmaniasis (CL). OBJECTIVE: Our purpose was to find out if a polymerase chain reaction (PCR) specific for Leishmania organisms might be more sensitive than the traditional diagnostic techniques, thereby decreasing the number of false-negative diagnoses. METHODS: In a prospective study, smear, culture, and histopathology of skin biopsy specimens from 46 patients with a possible diagnosis of CL were compared with PCR specific for Leishmania. In addition, the Montenegro test as a measure of cellular immunity against the Leishmania parasite was performed. Proven CL was defined as a case in which at least 1 of the 3 traditional tests showed the presence of Leishmania parasites. RESULTS: Of our 46 patients, 22 had leishmaniasis. Of the traditional tests, culture was the most sensitive but there were no statistically significant differences between the sensitivities of the various tests. PCR results were positive in all cases of proven leishmaniasis. Moreover, 3 patients with the clinical diagnosis of CL and negative findings on traditional tests had positive PCR results. Only 1 patient with a strong clinical suggestion of CL and positive Montenegro test results had negative PCR findings; this patient also had negative smear, culture, and histopathology results. CONCLUSION: PCR appears to be the most sensitive single diagnostic test for CL.