Lutzomyia lenti: A Neglected Species in the Transmission of Leishmaniasis In Brazil? A Review

Abstract

This article hypothesizes the possible involvement of Lutzomyia lenti in the transmission cycle of leishmaniases. Although its vector competence has not been confirmed, this study emphasizes the need for further research on the ecology of this species, its interactions with hosts, and the environmental factors influencing its distribution and population density to assess its potential role as a Leishmania vector.

Introduction

Leishmaniases are zoonotic diseases of great public health importance, caused by protozoa of the genus Leishmania. In Latin America, Leishmania infantum and Leishmania braziliensis are the main species responsible for visceral leishmaniasis (VL) and American tegumentary leishmaniasis (ATL), respectively. Both are transmitted through the bite of infected sand flies, affecting humans and animals, especially dogs [1,2].

In Brazil, over the past few decades, leishmaniasis has been undergoing a shift in its epidemiological profile, driven by the phenomenon of urbanization [3-6]. The geographical expansion of these diseases and the increasing incidence in urban and peri-urban areas highlight the need to further investigate vector ecology in order to understand the impacts of environmental changes on the transmission dynamics of VL and ATL.

Lutzomyia longipalpis is widely recognized as the primary vector of Leishmania infantum in Brazil. Its geographical distribution is extensive, covering almost the entire national territory, which reflects its ability to adapt to a wide range of environments. The high vectorial capacity of Lu. longipalpis is associated with its efficiency in transmitting this parasite, its anthropophilic feeding behavior, and its ecological plasticity, which enables the species to colonize various habitats [7,8].

In Brazil, Lutzomyia intermedia, Lutzomyia whitmani, Lutzomyia migonei, Lutzomyia umbratilis, and Lutzomyia wellcomei are identified as the main vectors of dermotropic Leishmania species. These species are distributed across different regions of the country, with Lu. intermedia being one of the most frequent, especially in urban and peri-urban areas [9], while the others predominate in wild, rural, and peri-urban environments [10].

The diversity of vectors and their adaptations to different environments are key factors in understanding the epidemiology of leishmaniases. The actual role of Lu. longipalpis in the ATL is not well established. Some studies indicate that Lu. longipalpis is a permissive vector, capable of being experimentally infected by certain Leishmania species that cause ATL [11-13]. Although there are occasional reports of dermotropic Leishmania species in Lu. longipalpis [14,15], natural transmission has yet to be confirmed.

On the other hand, some evidence suggests that other sand fly species may be contributing to the transmission cycle of Le. infantum, especially in areas where habitat overlap occurs or in locations with low Lu. longipalpis density [16]. These species have been identified with Le. infantum DNA, indicating exposure to the parasite [17-19] and a possible role in the VL transmission cycle, although their competence as vectors has not been fully elucidated.

The aim of this study was to critically synthesize the available evidence on Lutzomyia lenti (Mangabeira, 1938) and its previously overlooked potential role in leishmaniasis transmission. This review examines ecological characteristics, geographical distribution, reports of natural infection and indicators of potential vector competence, and also identifies knowledge gaps and priorities for future research.

To support this synthesis, a systematized literature search was conducted in PubMed, SciELO, Web of Science, Scopus, and Google Scholar (2004-2025), using the descriptors “Lutzomyia lenti,” “Evandromyia lenti,” “sand fly,” “Phlebotominae,” “Leishmania,” “vector competence,” and “ecology.” Studies providing occurrence records, ecological data, blood-feeding information, or evidence of natural infection were included, whereas those with unreliable identification, duplicated data or insufficient information were excluded. This approach ensured consistent retrieval of relevant evidence and enabled a comprehensive assessment of the species’ ecological and epidemiological relevance.

Geographical Distribution, Ecology, and Synanthropy of Lutzomyia lenti

In Brazil, Lu. lenti has a wide geographical distribution [20-23] and is commonly recorded in semi-arid regions, particularly in the Caatinga and Cerrado biomes. The geographical distribution of the species is consolidated in the classic literature [20,24]. Selected records of Lu. lenti (Ev. lenti) occurrence in Brazil (2004-2025) are summarized in Table 1, detailing locality, detection method, and associated methodological limitations. Additionally, there are reports of its occurrence in transitional areas towards the Atlantic Forest, demonstrating a certain degree of ecological plasticity [24]. Its presence appears to be more frequent in low-humidity environments, where it seeks refuge in natural shelters such as caves, rock crevices, and tree hollows.

Table 1. Selected Occurrence Records of Lutzomyia lenti (Ev. lenti) in Brazil: a Summary of Published Data (2004-2025).

Locality/State	Reference	Method(s)	Main findings	Limitations
Porteirinha/MG	Barata et al. (2004)	Systematic captures	Occurrence in VL transmission area, sympatric with Lu. longipalpis.	No parasitological or bloodmeal data.
Além Paraíba/MG	Brazil et al. (2006)	Entomological captures	Record of the phlebotomine fauna in a peridomiciliary area of VL.	Morphology-based ID only; no infection assessment or bloodmeal data.
Bela Vista/MS	Dorval et al. (2007)	Entomological captures; Isolation/Identification of Leishmania (isoenzymes)	Ev. lenti was collected in the area, along with 18 other sand fly species.	Natural infection status in Ev. lenti was not assessed or reported.
Várzea Grande/MT	Missawa et al. (2007)	Entomological captures	High density of Lu. longipalpis (VL vector) and Ny. whitmani (ACL vector) in the peridomicile areas.	Conducted in a single neighborhood; limited analysis on host feeding or infection status.
Bela Bista/MS	Dorval et al. (2009)	Entomological captures	Detection of Le. (L.) amazonensis in sentinel hamsters.	Study focused on a single geographic area; abundance and predominance results are specific to the capture method.
Campo Grande/MS	Paiva et al. (2010)	PCR/Molecular ID	Molecular detection of Leishmania in naturally infected sand flies.	PCR detection does not confirm vector competence.
Cáceres/MT	Alves et al. (2012)	Entomological captures using light traps at three rural settlements	Detection of Ev. lenti, which was ranked as the 4th most frequent species across the settlements.	No natural infection status or blood meal analysis was performed to incriminate Ev. lenti as a vector.
Various Municipalities/ES	Pinto et al. (2012)	Entomological captures; Cladistic analysis	Record of Ev. lenti in the Atlantic Forest biome; identified as an index species for the presence of Lu. longipalpis.	Not a current snapshot; no infection data for Ev. lenti.
Barra do Garças/MT	Queiroz et al. (2012)	Entomological captures	Recorded in urban area endemic for leishmaniasis.	Faunistic inventory; no Leishmania detection.
Central-western/MG	Nascimento et al. (2013)	Entomological captures	Record in sympatry with Lu. longipalpis.	No data on seasonality, density, or feeding behavior.
Monte Mor/SP	Cutolo et al. (2014)	Capture in Didelphis albiventris (opossum) nests in urban peridomestic sites	First report of Ev. lenti (one female specimen) associated with opossum nests in an urban area, demonstrating affinity with this synanthropic host.	Only one Ev. lenti specimen was captured; no infection or bloodmeal data for Ev. lenti was detailed.
Central-West Brazil (DF, GO, MS, MT)	Almeida et al. (2015)	Literature Review, Geographic Data Analysis, and Ecological Niche Modelling (Maxent)	Identified 127 species across the region. Confirmed the widespread distribution of major vectors: Lu. longipalpis (VL) and Ny. whitmani, and the high suitability of the Cerrado biome for sand flies.	Relies heavily on historical entomological records (1962–2014); models may generalize local environmental conditions.
São João das Missões/MG	Dutra-Rêgo et al. (2015)	PCR	Molecular detection of Leishmania.	No microscopy, culture, or experimental infection.
Nova Andradina/MS	Leite (2015)	Captures in forest fragments and peridomiciles (urban area); Natural Leishmania infection assessment	Record of Ev. lenti in urban/peri-urban ecotopes and natural infection assessment of the fauna.	Fauna study not exclusively focused on Ev. lenti; natural infection via PCR does not guarantee parasite viability or vector competence.
Lençóis Maranhenses/MA	Pereira Filho et al. (2015)	PCR + bloodmeal analysis	Detection of Leishmania DNA in L. lenti.	Possible residual DNA; no dissection or parasite isolation
Várzea da Palma/MG	Sanguinette et al. (2015)	Entomological captures	Most abundant species in the wild area of Northern MG.	Ecological study; no infection data reported for Ev. lenti.
Goiás/GO	Bastos et al. (2016)	Urban area captures (CDC traps)	Morphological identification of phlebotomine fauna.	Morphology-based ID only; no infection assessment or bloodmeal data.
Aquidauna/MS	Figueiredo et al. (2016)	Entomological captures in an endemic area	Record of Ev. lenti in the Pantanal biome and Leishmaniasis endemic area.	Morphology-based ID only; no specific infection or bloodmeal data for L. lenti.
Southeastern Brazil	Meneguzzi et al. (2016)	Environmental Niche Modelling (ENM) and GIS	Model identified Lu. intermedia as the main vector associated with American Cutaneous Leishmaniasis (ACL) risk across Southeastern Brazil.	Results rely on historical occurrence data; models may overestimate distribution due to broad climatic input.
Camapuã/MS	Fernandes et al. (2017)	Entomological captures	Species recorded in an urban area endemic for leishmaniasis.	Fauna inventory; no Leishmania detection reported for Ev. lenti.
Panorama/SP	Galvis-Ovallos et al. (2017)	CDC traps and synthetic pheromone traps (9MeG-B)	Studied the ecology of the pheromone-producing population of Lu. longipalpis in a VL endemic area.	Excludes other pheromone variants (e.g., cembrene, 3-methyl-alpha-himachalene) of Lu. longipalpis complex.
Fortaleza/CE	Rodrigues et al. (2017)	Entomological captures	Third most abundant species (after Lu. longipalpis and Lu. migonei) in a Visceral Leishmaniasis (VL) transmission area.	Study focused on the epidemiology of VL and Lu. longipalpis; Ev. lenti recorded as part of the fauna.
São Francisco River Transposition Area/CE	Santos-Silva et al. (2017)	Entomological captures	22 species found, including major vectors Lu. longipalpis (VL) and Ny. whitmani (ACL).	Study limited to pre- and early operational phases of the project; long-term epidemiological impact requires further monitoring.
Lençóis Maranhenses/MA	Fonteles et al. (2018)	PCR + bloodmeal identification	Additional record of Leishmania DNA in Lu. lenti.	PCR does not confirm viable infection; no dissection or culture
Multiple Municipalities/AL	Freitas et al. (2018)	Entomological captures	Occurrence confirmed in multiple municipalities (47 surveyed) across Atlantic Forest, Caatinga, and Coastal zones.	Specific list of municipalities not detailed in public abstracts.
South Pantanal/MS	Barrios et al. (2019)	Entomological captures; Synanthropy Index (SI)	20 species found. Lu. longipalpis was the most abundant and demonstrated high synanthropy, confirming its urban adaptation in this high VL transmission area.	Study is specific to the ecology of the Pantanal flood pulse, which limits generalizability to non-flooded areas.
Itaúna/MG	Lopes et al. (2019)	Canine survey (Serology, PCR); Companion study to entomological fauna analysis	High prevalence of Canine Visceral Leishmaniasis by Le. infantum in the municipality, confirming the intense transmission context where Ev. lenti was found infected	Primary focus on the canine reservoir; does not directly investigate Ev. lenti as a vector.
Urban area - Midwest Brazil	Menegatti et al. (2020)	Entomological captures	Urban record of Lu. lenti in the Central-West region.	No infection or ecological data
Itaúna/MG	Pereira et al. (2020)	Entomological captures	Species recorded in a municipality with recent VL transmission (Urban, Rural, and Forest areas).	Low abundance; study focused on major vectors (Lu. longipalpis and Ny. whitmani); No infection data for Ev. lenti.
Natal/RN	Silva et al. (2020)	CDC traps comparing UV light vs. LED bulbs (blue, green, red, white)	CDC traps with UV light captured significantly more sand flies than those with LED bulbs. Lu. longipalpis was one of the predominant species.	Focus on trap efficiency comparison; limited data on pathogen detection or host feeding.
Nísia Floresta/RN	Pinheiro et al. (2021)	Entomological captures	Found in Conservation Unit. Occasional in forest; subdominant in residential/anthropized areas.	Morphological-based ID only; no infection data.
Rio das Velhas/MG	Tonelli et al. (2021)	HP Light Traps (positioned in the middle of a river) and Mark-Release-Recapture (MRR)	Captured 6 specimens in the center of the river, including 1 Ev. lenti. Tested the hypothesis of continuous long flight capacity.	No recaptures of 1,450 marked-and-released sand flies, indicating limited success for the MRR part of the study.
Caxias/MA	Carvalho-Silva et al. (2022)	Entomological captures; PCR (ITS1) for Leishmania DNA	Detection of Le. amazonensis DNA in five species, including Ev. evandroi and Lu. longipalpis. Ev. lenti was collected but was not one of the species found positive for Le. amazonensis.	Le. infantum was not detected. PCR does not confirm viable infection or transmission.
Campo Grande/MS	Fernandes et al. (2022)	Entomological captures (2017–2019); Correlation with climatic variables.	Record of Ev. lenti in urban area; Fauna analysis focused primarily on L. longipalpis abundance.	Fauna study not exclusively focused on Ev. lenti; morphology-based ID implied; no infection or bloodmeal data for Ev. lenti.
Belo Horizonte/MG	Pereira et al. (2023)	CDC traps, Shannon traps, and mini-CDC traps; Blood meal analysis (PCR)	High diversity (15 species), including vectors Lu. longipalpis and Ny. intermedia. Host variety included humans, dogs, rodents, and tapirs.	Blood meal analysis limited to a subset of specimens; infection status not reported.
Miranda/MS	Souza et al. (2023)	Entomological captures	Record of Ev. lenti (low frequency) in an ecotourism area with high VL transmission risk by Lu. longipalpis.	Ev. lenti in low abundance (0.05%) and no reported infection test.
Teófilo Otoni/MG	Alonso et al. (2024)	Entomological captures	Lu. longipalpis was the most abundant species.	Study focused solely on the urban/peridomicile environment; did not include infection or blood meal analysis.
Cuité/PB	Alves et al. (2024)	Entomological captures	Confirms presence of Lu. lenti in Paraíba.	Morphology-based ID only; no infection assessment.
Andradina/SP	Leonel et al. (2024)	Entomological captures; PCR for Leishmania and vertebrate DNA (blood meal sources).	Detection of Le. amazonensis DNA in Ev. lenti (and Lu. longipalpis). Blood meals detected from swine, humans, dogs, cattle, chickens, and opossums in sand flies.	PCR does not confirm viable, transmissible infection; Le. amazonensis is typically associated with Cutaneous Leishmaniasis (CL), not Visceral Leishmaniasis (VL).
Museum of Zoology USP/SP	Conceição et al. (2024)	Curated museum specimens	Confirms distribution based on voucher specimens.	No epidemiological or ecological information.
Iguatama/MG	Dutra-Rêgo et al. (2024)	PCR (ITS1), Blood Meal	Detection of Le. infantum DNA in one female; Fed on Homo sapiens (human).	PCR does not confirm vector competence.
Lençóis Maranhenses National Park/MA	Rebêlo et al. (2024)	CDC Light Traps (Seasonal dynamics)	Ev. lenti was the most abundant. Abundance of sand flies, including vectors Lu. longipalpis and Ny. whitmani.	Focus on seasonal dynamics; requires further study on parasite transmission cycles and risk assessment for tourists.
Palmas/TO	Soares et al. (2024)	Morphology + COI DNA Barcoding	Species confirmed in Tocantins fauna. COI sequencing was ineffective in delimiting Evandromyia species.	COI marker was ineffective for species delimitation within the Evandromyia subgenus (Aldamyia).
Timóteo/MG	Souza et al. (2024)	CDC traps; PCR (Infection and Blood meal analysis)	Ny. intermedia was most abundant. Leishmania DNA detected in Ny. intermedia and Psathyromyia lutziana. Blood meals confirmed feeding on humans and dogs.	Parasite identification was limited to genus level (Leishmania spp.)
Aracaju/SE	Andrade et al. (2025)	Entomological surveillance and literature review	Ev. lenti was one of seven species found. The species showed a high degree of adaptability to the urban environment.	Ev. lenti abundance was lower than Lu. longipalpis; no infection or bloodmeal data from the surveillance was detailed.
Fortaleza/CE	Dantas da Silva (2025)	Morphological identification	High abundance.	Morphology-only record; no infection or bloodmeal data available.
Montes Claros/MG	Dias et al. (2025)	CDC Light Traps (domiciliary, peridomiciliary, forest)	Ny. intermedia was the most abundant species and the primary suspected vector in the ACL outbreak area. Lu. longipalpis was also present.	Primarily a faunistic survey; no parasitological analysis of the captured sand flies.
Brazilian cerrado	Haidar et al.(2025)	Manual aspirator (on snake) and HP light traps; PCR (SSU rRNA) for infection	Ev. lenti was the most frequent species, with some resting on the snake.	PCR detected only Trypanosomatid DNA, not confirming viable infection or the specific Trypanosoma species; study is a single, focused observation.

In general, the occurrence of phlebotomines in specific habitats is closely associated with the presence of particular vertebrate hosts. It is plausible to consider that Lu. lenti may be present in environments frequented by wild mammals. However, available records indicate that this species is predominantly found in anthropized areas, associated with the rearing of domestic animals [25,26], demonstrating a high degree of synanthropy. This characteristic may favor its interaction with domestic vertebrates and, potentially, with humans [27].

The ecology of Lu. lenti seems to be molded by anthropogenic alterations, notably land use and urbanization. Deforestation and agro-livestock expansion create ecotones that facilitate the species’ dispersion and adaptation to new shelters. Adaptation to peridomestic and urban environments is critical, as it raises the potential for contact with domestic reservoirs (eg, dogs) and humans, especially in areas of sympatry with Lu. longipalpis [25,28].

Furthermore, climatic factors crucially influence population dynamics and vector potential. Variables such as temperature and humidity affect the sand flies’ survival and longevity. For instance, rising temperature may reduce the extrinsic incubation period of Leishmania, accelerating the transmission cycle. Continuous monitoring of these variables is essential for predictive modeling and delimiting areas under potential epidemiological risk [5].

Sympatry with Lu. longipalpis and the Vector Potential of Lu. lenti

Lutzomyia lenti has frequently been recorded in sympatry with Lu. longipalpis in various regions of the country [29-32]. This pattern suggests that both species share similar ecological niches, including feeding sources and shelter sites. Their coexistence in endemic areas may indicate that Lu. lenti benefits from the same conditions that favor Lu. longipalpis, such as the presence of vertebrate hosts and the availability of suitable sites for oviposition and larval development.

Moreover, this association may indicate an ecological interaction between the species, which could involve competition, resource sharing, or even the possibility of Lu. lenti acting as a secondary vector in the transmission of Le. infantum. It would not be unlikely to consider that, if Lu. lenti also feeds on infected vertebrates, its role in the epidemiological cycle of VL may be underestimated.

This scenario is particularly relevant in regions where Lu. longipalpis exhibits seasonal variations in population density, suggesting that Lu. lenti could contribute to the maintenance of the parasite during periods of low abundance of the primary vector. Some studies have reported PCR detection of Leishmania DNA in Lu. lenti, an indication of exposure to the parasite rather than evidence of active infection or vector competence, underscoring the need for further investigations into the species’ potential involvement in transmission dynamics.

Studies have reported the PCR detection of Leishmania DNA in Lu. lenti [33-35], which represents an indication of exposure to the parasite, but is not proof of active infection or vector competence. These findings must be interpreted with caution, as molecular detection does not confirm parasite viability and may reflect residual DNA from recent bloodmeals. The high sensitivity of the technique makes it susceptible to contamination during field and laboratory procedures. As no complementary evidence is available, such as microscopic visualization of promastigotes, isolation in culture, or experimental infections demonstrating metacyclogenesis, PCR represents a low level of evidence in the vector incrimination process.

Phylogeny and Implications of the Vector Competence of Lu. lenti in the Epidemiology of Leishmaniases

Another relevant factor is that Lu. lenti belongs to the migonei group [24], which comprises phylogenetically related species. Lutzomyia migonei, for instance, has been considered a putative vector of Le. infantum in some regions of Brazil and Argentina [18,19,36], in addition to its confirmed role as a vector of Le. braziliensis [37,38]. This phylogenetic and ecological proximity suggests that Lu. lenti may share biological traits potentially relevant to vector competence, although no evidence currently supports this assumption.

Although there is still no definitive evidence of its vector competence, the presence of Lu. lenti in endemic areas and the detection of Leishmania spp. suggest that its role in the epidemiology of leishmaniases should be investigated in greater depth. It is essential to conduct periodic collections in different locations to monitor the presence and distribution of Lu. lenti, particularly in endemic areas. Comparing the abundance and distribution of this species over time and under different environmental conditions, along with identifying seasonal variations in its density, may provide valuable insights into its ecology and potential role in the transmission of Leishmania.

An interesting strategy for studying the vector competence of Lu. lenti is the analysis of infection rates, which can be performed using different laboratory techniques. Polymerase chain reaction (PCR) is a highly sensitive molecular approach that allows the detection of Leishmania DNA in captured sand flies, even when the parasite load is low [39]. However, PCR does not provide information on active infection or parasite viability, as it is limited to identifying the protozoan’s genetic material.

On the other hand, the dissection of the sand fly’s digestive tract is a traditional technique used to identify active infections, allowing direct observation of parasites within the vector [40,41]. However, this approach has reduced sensitivity when the parasite load is low, which may hinder the detection of incipient or low-level infections.

The cultivation of the parasite in specific media, such as NNN/LIT, allows the confirmation of active infection and provides data on parasite viability, which is essential for assessing vector potential [42,43]. However, cultivation is a more labor-intensive process, and its success may vary depending on collection conditions and parasite viability. By combining these approaches, it is possible to overcome the limitations of each individual technique, leading to a more accurate assessment of the species’ vector competence.

The study of a species’ vector competence involves assessing its ability to acquire, maintain, and transmit Leishmania. In laboratory experiments, female sand flies can be fed on the blood of infected vertebrates, allowing for the analysis of the parasite’s developmental cycle within the insect and its ability to transmit to susceptible hosts [44,45]. Additionally, it is crucial to evaluate factors such as parasite load and infection duration, as these parameters help determine the species’ efficiency as a vector.

The discussion would benefit from a ranking of the strength of evidence in the vector incrimination process: PCR alone represents the lowest level, indicating only exposure. The combination of PCR plus microscopy attests to the parasite’s presence, but without confirming viability. Culture isolation significantly raises the strength, confirming parasite viability and multiplication capacity. The maximum level of evidence is achieved through experimental transmission, which proves the sand fly’s ability to infect a susceptible host [40].

The study of blood-feeding in sand flies plays a crucial role in assessing their vectorial capacity. Research on the interactions of Lu. lenti with vertebrate hosts, including wild and domestic mammals, is essential to identify which species are more attractive for feeding and, consequently, more likely to act as Leishmania reservoirs. To achieve this identification, techniques such as PCR on regurgitated blood, blood extract analysis, Enzyme-Linked Immunosorbent Assay (ELISA), and precipitin tests can be employed [46-49].

Bloodmeal source analysis constitutes a critical component of vector incrimination, demanding thorough elaboration. The feeding preference of Lu. lenti establishes the epidemiological link with reservoir hosts that sustain the Leishmania cycle. Demonstrating feeding on known reservoirs in sympatric zones is imperative for confirming the species’ potential role. Such data are crucial for calculating vectorial capacity, thereby parameterizing the actual risk of transmission [40].

Molecular identification of the blood source is crucial to contextualize PCR findings. Given that isolated PCR only signals exposure to the parasite, correlating Leishmania DNA with a known reservoir’s blood elevates the level of evidence. Techniques like PCR followed by sequencing of blood remnants enable distinguishing epidemiologically relevant hosts from opportunistic feeding [42,50]. This detail is essential for guiding subsequent experimental studies and validating the putative role of Lu. lenti.

To confirm the putative vector competence of Lu. lenti and overcome the limitations of PCR, controlled experimental studies are crucial. These must begin with experimental infections (eg, membrane feeding with viable Leishmania) followed by defined dissection timelines (3, 7, and 10 days post-infection). The objective is to monitor parasite development, migration to the pharynx, and metacyclogenesis, thus confirming transmission potential. Complementarily, the results of these experimental findings must be integrated with the comprehensive bloodmeal analyses of field specimens to correlate the sand fly’s biological potential with its natural hosts.

Another aspect to consider is the influence of environmental factors on the ecology of sand flies and, consequently, on the transmission of leishmaniases. Variables such as temperature, humidity, rainfall, availability of shelters, and presence of hosts play a crucial role in the distribution and abundance of these vectors [51-53]. These environmental conditions may favor the expansion of sand flies into new areas, altering epidemiological patterns and potentially increasing the risk of Leishmania transmission in non-endemic regions.

Major Research Gaps and Priorities

The analysis of the literature on Lu. lenti reveals critical gaps that prevent the definitive confirmation of its potential vector role, thus outlining the essential priorities for future investigations. The most evident deficiency lies in the absence of direct proof of vector competence. It is imperative to transition from isolated PCR findings, which represent the lowest level of evidence, to experimental transmission (the gold standard for incrimination). This demands laboratory studies that demonstrate the species’ ability to acquire, maintain, and transmit the metacyclic forms of the parasite after a successful extrinsic incubation period.

Secondly, a fundamental knowledge gap persists regarding host-feeding behavior. Although bloodmeal analysis is mentioned, robust data on the frequency with which Lu. lenti feeds on known zoonotic reservoirs are lacking. This ecological information is crucial to validate the species’ putative role in the transmission cycle and to calculate its true vectorial capacity in sympatric environments.

Finally, there is a gap in epidemiological and ecological predictive modeling. Future studies must integrate climatic and land use variables to build rigorous predictive models of Lu. lenti’s distribution and abundance. Identifying ecological factors that influence population density and the potential risk is vital for informing targeted surveillance and control strategies in areas of leishmaniasis expansion.

Final Considerations

The hypothetical role of Lu. lenti as a secondary vector in the transmission of VL and/or ATL may pose a significant challenge in the epidemiology of these diseases. Confirming Lu. lenti as a vector would also require new approaches to prevention and control, as well as a shift in the focus of vector control campaigns, which have traditionally targeted Lu. longipalpis. This would involve greater investment in continuous monitoring, research, and management strategies to address the complexity of leishmaniasis transmission cycles.

This review does not seek to raise alarm about the possible role of Lu. lenti as a secondary vector in the transmission of VL and/or ATL, but rather to emphasize the importance of further investigations into this species, whose involvement in disease transmission remains uncertain. The available evidence indicates the need for more studies to better understand the ecology and vector competence of Lu. lenti. Thus, future research is expected to provide a solid foundation for improving efficient surveillance and control strategies for leishmaniases.

Glossary

VL

visceral leishmaniasis

ATL

American tegumentary leishmaniasis

PCR

Polymerase chain reaction

Author Contributions

RAB: Study conception and design, acquisition of data, drafting of manuscript, critical revision.