Testing the versatility of a Psychodiella sp. diagnostic assay in field surveys.

LORENA G. CALIGIURI; ENRIQUE A. SANDOVAL; MA. SOLEDAD SANTINI; SORAYA A. ACARDI; OSCAR D. SALOMÓN; LILIAN TARTAGLINO; *CHRISTINA B. MCCARTHY

Puerto Iguazú

Simposio; VIII International Symposium on Phlebotomine Sandflies (ISOPS VIII); 2014

Instituto Nacional de Medicina Tropical; Ministerio de Salud, Presidencia de la Nación

Psychodiella chagasi natural infections have previously been recorded in Lutzomyia longipalpis from Lapinha (Minas Gerais) (Adler and Mayrink, 1961), Jacobina (Bahia) in Brazil (Lantova et al., 2010) and, recently, Posadas (Argentina) (McCarthy et al. 2011). Given the fact that the Argentine Lu. longipalpis population is significantly differentiated from Brazilian populations (Salomon et al. 2010), we were interested in developing a straightforward and sensitive assay to analyse the incidence of natural gregarine infections in Lu. longipalpis from this location. In this context, we recently reported the first PCR-based assay for the detection and identification of natural gregarine infections in Lu. longipalpis (Caligiuri et al., 2014). Briefly, sand fly gregarine diagnostic primers PsyF and PsyR were designed on the basis of Ps. chagasi SSU rDNA sequences we previously identified in male Lu. longipalpis from Posadas (McCarthy et al. 2011). The specificity and sensitivity of the diagnostic primers were confirmed by in silico analysis and in vitro and field validations using total DNA extracted from naturally infected Lu. longipalpis (Caligiuri et al., 2014). Having validated our diagnostic assay for sand fly gregarine parasites in Lu. longipalpis, we were interested in testing its versatility for subsequent use in field surveys. Therefore, to evaluate the perfomance of the assay in a wider range of field captured Lu. longipalpis, we analysed 159 captured individuals from this species from Posadas (Argentina), using samples made up of one sand fly each and pools of 5 and 10 sand flies using different protocols and conditions. As expected, to obtain consistent results for the samples made up of one sand fly each, it was necessary to optimise the DNA extraction protocol. Our results indicated that the diagnostic assay is very versatile for field surveys and can be adapted to different sampling designs. Furthermore, in accordance with our previous results, the diagnostic assay detected gregarine infections that were not observed previously by light microscopy analysis.