SHAH JS, HARRIS NS; Interscience Conference on Antimicrobial Agents and Chemotherapy.
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 1999 Sep 26-29; 39: 732 (abstract no. 1859).
IGeneX, Inc., Palo Alto, CA.
Babesiosis is caused by an intraerythrocytic parasite, Babesia microti. Babesiosis is usually diagnosed by the examination of Giemsa-stained thin blood smears. However, the ring form of the parasite is often confused with ring forms of malaria species. There are indirect immunofluorescence assays (IFAs) using polyclonal antibodies directed against B. microti. These tests too, lack specificity. Isolation and culture of these parasites as a diagnostic method would provide adequate specificity and sensitivity, however it is not considered technically or economically feasible. We have developed a very simple nucleic acid based diagnostic test -- Fluorescent In-Situ Hybridization (FISH) Assay. The FISH test is a non-amplified assay for direct detection of B. microti RNA in whole blood smears. The test is highly specific. In addition, the test provides morphological information. This test was performed on 221 air-dried thin blood smears from patients with Babesiosis-like symptoms. FISH was considered positive if either the ring form or the merozoite form or both forms were present in the red cell. In addition, polymerase chain reaction (PCR) test for B. microti, was performed on EDTA treated whole blood samples from these patients. Of the 221 samples, 73 samples (33%) were positive by FISH. Of these, 56 samples were positive by PCR. In addition, 27 samples, negative by FISH were positive by PCR. After discrepant analysis, 58 samples (26.2%) were considered FISH positive and 83 samples (37.5%) PCR positive. Based on the data presented here, the specificity and sensitivity of FISH assay as compared to PCR assay were 93% and 68%, respectively. Thus, the FISH assay, when used in conjunction with clinical symptoms for Babesiosis could improve patient diagnosis. In addition, it provides a tool to follow patients during treatment.
Publication Types:
Keywords:
- Animals
- Babesiosis
- Fluorescent Antibody Technique, Indirect
- Humans
- In Situ Hybridization, Fluorescence
- Polymerase Chain Reaction
- Sensitivity and Specificity
- parasitology
Other ID:
UI: 102246463
From Meeting Abstracts