C-226. Rapid, Specific and Easy Diagnosis of Trypanosoma cruzi by PCR-Oligochromatography Using the T. cruzi OligoC-TesT

X. Coronado1, S. Deborggraeve1, P. Y. M. G. Mertens2, T. H. Laurent2, T. Leclipteux2, P. Büscher1;
1Inst. of Tropical Med., Antwerp, BELGIUM, 2CorisBioconcept, Gembloux, BELGIUM.

Chagas' disease is caused by Trypanosoma cruzi, a parasite that is transmitted to humans by the faeces of blood-sucking triatomines. Although described as endemic to South America, the disease could be problematic in other countries since the parasite can be transmitted by blood transfusion and transplacentally. Approximately 30% of the 16 million infected people will progress to irreversible pathology, causing considerable morbidity and mortality. In the first, acute phase of the disease, parasitaemia can be high, allowing an efficient diagnosis. The latent and chronic phases are characterised by a low parasitaemia making diagnosis more difficult. The high specificity and sensitivity of PCR makes it a valuable tool for parasite detection, in particular for assessing parasitological cure after specific treatment as well as for blood bank and congenital transfert testing. We have developed an innovative assay that combines the high sensitivity and specificity of PCR with the ease and speed (5 minutes) of oligochromatographic detection (OligoC-TesT). Several PCRs were developed of which the PCR targeting the satellite DNA showed the best combination of high analytical sensitivity for T. cruzi and low cross-reactivity with T. rangeli, a closely-related but non-pathogenic parasite with a similar distribution as T. cruzi. An internal control was added to the PCR to check for inhibitors potentially present in the analyzed sample and dUTP is used to allow carry-over contamination control. The lower detection limit of this T. cruzi OligoC-TesT, was 1fg when evaluated on serial dilutions of T. cruzi genomic DNA. When evaluated on spiked blood samples, the test could detect as few as 1 parasite in 180µl blood. Tests performed on clinical samples showed a sensitivity of 95.5% and specificity of 100% with the kDNA PCR and serology as reference tests. In conclusion, we have developed and evaluated the T. cruzi OligoC-TesT which combines PCR with easy and rapid oligochromatographic detection. The high analytical sensitivity and the high performance when validated on clinical samples shows the great potential of this new tool for the detection of T. cruzi.