Identification of sand flies (Diptera: Psychodidae) and blood meal sources in periurban areas of Ji-Paraná municipality, Western Brazilian Amazon

aPrograma de Pós-graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, BR 364, Km 9.5, CEP 76801-059, Porto Velho, RO, Brasil bLaboratório de Entomologia, Fundação Oswaldo Cruz – Fiocruz Rondônia, Rua da Beira, 7671, CEP 76812-245, Porto Velho, RO, Brasil cInstituto Nacional de Epidemiologia da Amazônia Ocidental – INCT-EpiAMO, Rua da Beira, 7671, CEP 76812-245, Porto Velho, RO, Brasil dLaboratório de Epidemiologia Genética, Fundação Oswaldo Cruz – Fiocruz Rondônia, Rua da Beira, 7671, CEP 76812-245, Porto Velho, RO, Brasil *e-mail: junior.ampj@gmail.com


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Leishmaniases is a disease caused by Leishmania protozoans which are transmitted to vertebrates by the bite of female sand flies. Epidemiological surveillance depends on the identification of vector species and their reservoirs, and identifying sand fly blood meal sources can be an effective means of identifying potential reservoirs in the Leishmaniasis transmission cycle (Roque and Jansen, 2014). In Rondônia State, approximately 1,000 new cases of cutaneous leishmaniasis (CL) occur annually (DATASUS, 2018). In Ji-Paraná municipality, which is located in the eastern mesoregion of Rondônia (see Figure 1), 418 cases of CL have been registered since 2007 (DATASUS, 2018); in spite of this, there is not much information about Leishmania infection, sand fly vectors and, their blood sources that occur there (Biancardi et al., 1982). The aims of our study was to verify these insects and possible blood meals in Ji-Paraná municipality.
Sand fly collections were made using light traps that were set for three consecutive nights in small forest fragments near eight periurban areas (see Figure 1C). Two collections were performed: one in November of 2017 and another in November of 2018. Males and females (head and last segments) were slide-mounted and morphologically identified (Galati, 2018).
In order to screen for the presence of Leishmania DNA, the thoraxes of non-engorged females were separated into pools and subjected to polymerase chain reaction assays using primers targeting kDNA (Pereira Júnior et al., 2019). The Le. amazonensis strain (IFLA/BR/1967/PH8) was used as the positive control and ultrapure water was used as the negative control. Blood meal sources were identified by submitting the thoraxes of engorged females to DNA extraction using the phenol/chloroform protocol; to avoid sample contamination, two samples containing a female with no blood present in the gut and one sample containing DNA-free water were used as negative controls.
Extracted DNA was subjected to PCR assays targeting the cytb mitochondrial region (Pereira Júnior et al., 2019).
Blood meal analysis revealed the DNA of Homo sapiens in one Ps. davisi female and four Ps. hirsutus hirsutus females, while DNA of the wild vertebrates Alouatta seniculus and Dasypus sabanicola was present in the gut of two Ps. hirsutus hirsutus females (as shown in Table 2). Dasypus sabanicola is not found in Brazil (Abba and Superina, 2010) and probably the DNA sequence could be another species of Dasypus genera with distribution in the Brazilian Amazon as Dasypus novemcinctus or Dasypus kappleri.
The finding that Ps. hirsutus hirsutus and Ps. davisi feed on wild vertebrates may help to improve our understanding of the hematophagous habits of these species as well as our understanding of the Leishmania transmission cycle in this region. The presence of H. sapiens DNA in engorged sand flies combined with the high abundance of these species indicates that humans have been exposed to bites from potential vectors in four of the eight localities in Ji-Paraná.