[Differential diagnosis of imported filariasis by molecular techniques (2006-2009)]

Abstract

Introduction: The last few years has seen an increase in the number of immigrants and travellers from endemic areas where filariasis are mainly caused by Loa loa (L. loa), Mansonella perstans (M. perstans) and Wuchereria bancrofti (W. bancrofti) species. These demographic changes has led to the need for better filariae species-specific molecular diagnostic tests to solve problems, as alternatives to the more time consuming classic parasitology methods. Thus, the objective of the present work was the implementation of optimised molecular protocols (nested-PCR and ITS1-RFLP) developed in our laboratory, for the differential diagnosis of filarial parasites. The results obtained were compared with those obtained using the conventional parasitological methods.

Material and methods: A total of 523 samples (517 peripheral blood, 5 adult worms and one vitreous body) were sent to Parasitology Department of the National Microbiology Centre, Carlos II Research Institute (ISCIII), from 47 Health Centres in the Autonomous Regions of Spain, from 2006 to 2009. The samples were studied by the Knott technique, nested-PCR and ITS1-RFLP.

Results: The molecular techniques applied on blood samples showed to be more sensitive that Knott's concentration technique in the diagnosis of both L. loa (n=12 versus n=4) and M. perstans (n=57 versus n=25) infections.

Conclusions: The nested-PCR and ITS1-RFLP are potential diagnostic tools for daily routine laboratory species-specific and sensitive detection of L. loa and M. perstans filarial species in immigrant population and travellers from endemic areas where these filarial species are co-endemic. Knott's concentration technique was less sensitive than molecular methods and should be carried out as a complementary diagnostic assay.