Experimental infections and co-infections with Leishmania braziliensis and Leishmania infantum in two sand fly species, Lutzomyia migonei and Lutzomyia longipalpis

Abstract

Leishmaniases are neglected tropical diseases and Leishmania (Leishmania) infantum and Leishmania (Viannia) braziliensis are the most important causative agents of leishmaniases in the New World. These two parasite species may co-circulate in a given endemic area but their interactions in the vector have not been studied yet. We conducted experimental infections using both single infections and co-infections to compare the development of L. (L.) infantum (OGVL/mCherry) and L. (V.) braziliensis (XB29/GFP) in Lutzomyia longipalpis and Lutzomyia migonei. Parasite labelling by different fluorescein proteins enabled studying interspecific competition and localization of different parasite species during co-infections. Both Leishmania species completed their life cycle, producing infective forms in both sand fly species studied. The same happens in the co infections, demonstrating that the two parasites conclude their development and do not compete with each other. However, infections produced by L. (L.) infantum reached higher rates and grew more vigorously, as compared to L. (V.) braziliensis. In late-stage infections, L. (L.) infantum was present in all midgut regions, showing typical suprapylarian type of development, whereas L. (V.) braziliensis was concentrated in the hindgut and the abdominal midgut (peripylarian development). We concluded that both Lu. migonei and Lu. longipalpis are equally susceptible vectors for L. (L.) infantum, in laboratory colonies. In relation to L. (V.) braziliensis, Lu. migonei appears to be more susceptible to this parasite than Lu. longipalpis. Leishmaniases are important parasitic diseases, causing serious medical problems in many countries, as they rank in the top-three list of neglected tropical diseases caused by protists 1. The causative agents, flagellates of the genus Leishmania (Kinetoplastida: Trypanosomatidae), subgenera Leishmania and Viannia, are transmitted by phlebotomine sand flies (Diptera: Psychodidae) 2. In Brazil, Leishmania (Leishmania) infantum and Leishmania (Viannia) braziliensis are the most important causative agents of leishmaniases in humans 3. L. (V.) braziliensis causes a typical cutaneous leishmaniasis (CL), which may progress to mucosal disease, whereas L. (L.) infantum infections is responsible for a life-threatening form of the disease-visceral leishmaniasis (VL). These two parasite species also differ in their development in the sand fly vector; both colonize the sand fly midgut, but only L. (V.) braziliensis was documented to colonize the hindgut (peripylarian development) 4 .

Diversity of phlebotomine sand flies and molecular detection of trypanosomatids in Brumadinho, Minas Gerais, Brazil

“…Migonemyia migonei has also been implicated in the cycle of Le. braziliensis [62][63][64] and their capacity to support infections with this parasite have been confirmed by Alexandre et al [65]. The genus Evandromyia presented the highest number of species and although there are no proven vector species within this genus, natural infection or Leishmania DNA has been detected in some species [66,67].…”

Revisiting the Phlebotominae subfamily records in Bahia, Brazil

“…Interestingly, despite being recognized as an ATL vector, Mg. migonei has also been found naturally infected by L. infantum in endemic AVL areas in northeastern Brazil (Carvalho et al, 2010;Rodrigues et al, 2016) and more recently in Porto Alegre, southern Brazil (Rêgo et al, 2020). Experimental work showed rates of Mg. migonei infection by L. infantum and L. braziliensis of 90 and 68%, respectively (Alexandre et al, 2020).…”

Phlebotomine Sand Flies in Southern Thailand: Entomological Survey, Identification of Blood Meals and Molecular Detection of Trypanosoma spp.

“…These findings suggest that sand flies in southern Thailand may be incriminated in transmission of both Leishmania and Trypanosoma protozoans. Although Trypanosoma DNA detection in sand fly species has been reported continuously, the complete information of Trypanosoma life cycle remains uncertain, while the life cycle of Leishmania in sand flies has been suggested as a natural vector of Leishmania [26,27]. However, little is known about the biology and feeding preferences of sand flies that may provide important insight into their transmission cycle and potential reservoir hosts.…”