Characterization of human infection by Leishmania spp. in the Northweast of Argentina: humoral immune response, double infection with T. cruzi and species of Leishmania involved.

FRANK FM, FERNÁNDEZ MM, TARANTO NJ, CAJAL S, MARGNI RA, CASTRO E, SOCCOL V & MALCHIODI EL.

PARASITOLOGY

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2003 vol. 169 p. 31 - 39

0031-1820

The aims of this study were to characterize human American tegumentary leishmaniasis, that includes or including cutaneous, mucocutaneous and mucosal leishmaniasis, in Northwest Argentina, determine the prevalence of double infection with Trypanosoma cruzi and identify the species of Leishmania in this area.  Most of the 330 leishmaniasis patients presented cutaneous ulcers (96.1%), 2.4% mucocutaneous and 1.5% the mucosal form (“espundia”).  The aetiological agents, determined by isoenzyme electrophoresis, were identified as Leishmania (Viannia) braziliensis in 16 out of 20 isolates and in the remaining four as Leishmania (Leishmania) amazonensis, the first ever-documented in Argentina.  Sera analysed by ELISA and IFA using complex antigen from both T. cruzi and L. braziliensis showed a very high percentage of positives (66.3-78.2%).  When antigens for specific diagnosis of Chagas´ disease were used, 40.9% of the leishmaniasis patients were also found to be infected by T. cruzi.  These results indicate that the strong immune response against T. cruzi gave no protection to Leishmania, in spite of the serological cross-reaction between these parasites.  Further, we showed that more than 40% of the patients would be misdiagnosed as chagasic if complex antigens, as epimastigotes or soluble fraction from epimastigotes in IFA or ELISA, were used.  This is of paramount importance not only because patients´ treatment would be associated to misdiagnosis but the fact that in many countries in Central and South America, a positive test for Chagas´ disease means an automatic rejection for those applying for a job.