Strategy for identifying Psychodiella chagasi, a putative control agent for Lutzomyia longipalpis, Visceral Leishmaniasis vector

LORENA G. CALIGIURI; ENRIQUE A. SANDOVAL; CHRISTINA B. MCCARTHY

Taipei

Conferencia; 5th International Conference on Industrial Bioprocesses (IFIB-2012); 2012

Leishmaniasis is one of the most diverse and complex of all vector-borne diseases worldwide. It is caused by parasites of the genus Leishmania, obligate intramacrophage protists characterised by diversity and complexity. Its most severe form is visceral leishmaniasis (VL), a systemic disease that is fatal if left untreated. In Latin America VL is caused by Leishmania infantum chagasi and transmitted by Lutzomyia longipalpis. This phlebotomine sandfly is only found in the New World, from Mexico to Argentina. In South America, migration and urbanisation have largely contributed to the increase of VL as a public health problem. Moreover, the first VL outbreak was recently reported in Argentina (Salomon et al. 2008), which has already caused 7 deaths and 83 reported cases. Given this recent outbreak and the compelling need to develop appropriate control strategies, an unbiased and comprehensive metagenomic approach was used for the first time to survey taxa associated with any infectious disease vector (McCarthy et al. 2011). This study focused on wild male and female Lu. longipalpis from an Argentine endemic (EVL) (Posadas, Misiones) and a Brazilian non-endemic (Lapinha Cave, Minas Gerais) VL location. Among others, sequences of a protist gregarine that parasitises Lutzomyia spp., Psychodiella chagasi, were found in EVL males. Even though the use of P. chagasi as a control method in the field has not been considered efficient because the parasite seems to have a limited range and a minimal effect on sandfly biology under natural conditions (Soares and Turco 2003), the fact that we found P. chagasi in randomly caught wild specimens, suggested it could be a more efficient control method under natural conditions than what was previously reported. In this sense, we developed a strategy to analyse the presence and establish the significance of P. chagasi in a greater number of adult male and female Lu. longipalpis samples. For this, we designed primers using the P. chagasi sequences we identified by homology in the phlebotomine samples. Their efficiency and specificity were confirmed by PCR amplification using the original cDNA obtained from Lu. longipalpis as template. The amplified P. chagasi sequences were cloned, sequenced and their identity confirmed by sequence homology. The primers were then used to analyse a greater number of adult male and female Lu. longipalpis samples from an endemic VL location (Posadas, Argentina). Our results confirmed the presence and significance of P. chagasi as a putative control method for Lu. longipalpis and opened a wide spectrum of future applications. Among these, the development of a cost-effective bio-process for the safe release of this gregarine to control VL vectors.