Experimental infection and transmission of Leishmania by Lutzomyia cruzi (Diptera: Psychodidae): Aspects of the ecology of parasite-vector interactions

Abstract

Several parameters should be addressed before incriminating a vector for Leishmania transmission. Those may include its ability to become infected by the same Leishmania species found in humans, the degree of attractiveness for reservoirs and humans and capacity to sustain parasite infection under laboratory conditions. This study evaluated the vectorial capacity of Lutzomyia cruzi for Leishmania infantum and gathered information on its ability to harbor L. amazonensis. Laboratory-reared Lu. cruzi were infected experimentally by feeding them on dogs infected naturally with L. infantum and hamsters infected with L. amazonensis. Sand fly attractiveness to dogs and humans was determined using wild caught insects. The expected daily survival of infected Lu. cruzi, the duration of the gonotrophic cycle, and the extrinsic incubation period were also investigated for both parasites. Vector competence was investigated for both Leishmania species. The mean proportion of female sand flies that fed on hosts was 0.40. For L. infantum and L. amazonensis, Lu. cruzi had experimental infection rates of 10.55% and 41.56%, respectively. The extrinsic incubation period was 3 days for both Leishmania species, regardless of the host. Survival expectancy of females infected with L. infantum and L. amazonensis after completing the gonotrophic cycle was 1.32 and 0.43, respectively. There was no association between L. infantum infection and sand fly longevity, but L. amazonensis–infected flies had significantly greater survival probabilities. Furthermore, egg-laying was significantly detrimental to survival. Lu. cruzi was found to be highly attracted to both dogs and humans. After a bloodmeal on experimentally infected hosts, both parasites were able to survive and develop late-stage infections in Lu. cruzi. However, transmission was demonstrated only for L. amazonensis–infected sand flies. In conclusion, Lu. cruzi fulfilled several of the requirements of vectorial capacity for L. infantum transmission. Moreover, it was also permissive to L. amazonensis.

Hidden danger: Unexpected scenario in the vector-parasite dynamics of leishmaniases in the Brazil side of triple border (Argentina, Brazil and Paraguay)

“…migonei is a permissive vector for L . infantum , and Oliveira et al [ 52 ] reported an experimental infection rate of 10.6% for L . infantum in Lu .…”

Epidemiological aspects of Leishmaniasis in the Pantanal region of Mato Grosso

“…Important species in the transmission of the etiological agent of VL were observed in five out of the seven municipalities that were part of the research (BRASIL, 2014). Lutzomyia longipalpis, the main vector in Brazil, is present in most member states, demonstrating the high adaptability to different types of vegetation, climates, habitats and food availability (LAINSON & RANGEL, 2005;FALCÃO DE OLIVEIRA et al, 2017). Lutzomyia cruzi is the Leishmania infantum vector in some areas of Mato Grosso do Sul (FALCÃO DE OLIVEIRA et al, 2017) and Mato Grosso (BRITO et al, 2014b).…”

“…Lutzomyia longipalpis, the main vector in Brazil, is present in most member states, demonstrating the high adaptability to different types of vegetation, climates, habitats and food availability (LAINSON & RANGEL, 2005;FALCÃO DE OLIVEIRA et al, 2017). Lutzomyia cruzi is the Leishmania infantum vector in some areas of Mato Grosso do Sul (FALCÃO DE OLIVEIRA et al, 2017) and Mato Grosso (BRITO et al, 2014b). The highest frequency of L. cruzi was found in municipalities within Pantanal and Cerrado, indicating that these are the preferred environments of this species (MISSAWA & LIMA, 2006).…”

Ecological niche modelling and predicted geographic distribution of Lutzomyia cruzi, vector of Leishmania infantum in South America

“…cruzi may be acting as the main vector of this protozoan due to absence of L . longipalpis [ 21 – 25 ]. Although there were suspicions that L .…”

“…infantum since the 1980s [ 21 , 22 ], only recently this phlebotomine sand fly was confirmed as a proven vector of L . infantum [ 25 ], based on the Killick-Kendrick criteria [ 26 ], and as a permissive vector of L . amazonensis [ 25 ].…”