Species structure of sand fly (Diptera: Psychodidae) fauna in the Brazilian western Amazon

Diversity, vertical stratification and detection of Leishmania DNA in sand flies (Diptera: Psychodidae) collected in the Mapinguari National Park, Brazilian Amazon

This study aimed to assess the diversity patterns of sand fly fauna across different strata and detect Leishmania DNA in these insects in the Mapinguari National Park in Rondônia and Amazonas states, Northern Brazil. Sand flies were collected with "HP" light traps in the canopy (15 m) and at ground level (1 m) on two trails, during August and November 2021 and March and August 2022. Polymerase chain reaction and DNA sequencing were used to identify Leishmania species. A total of 8,040 individuals (2,303♂ - 28.64 %, 5,737♀ - 71.36 %) were collected and 53 species and 13 genera were identified. The most abundant species were Psychodopygus chagasi (21.00 %), Trichophoromyia ubiquitalis (13.61 %) Psychodopygus davisi (11.69 %), Nyssomyia fraihai (10.58 %), Nyssomyia antunesi (6.68 %) and Nyssomyia richardwardi (5.55 %). Species diversity was greater in the canopy (Shannon index H' = 10.8 common species) when compared to ground level (H' = 10.5 common species). We observed a minimum infection rate of 0.45 % (22/4,868 females), in which Leishmania braziliensis DNA was found in Ps. chagasi and Le. lainsoni DNA in Ps. chagasi, Ny. richardwardi, Ps. ayrozai and Th. ubiquitalis. The minimum infection rate of Leishmania in the canopy was 0.47 % (19/4,031) and in the ground was 0.52 % (3/567). In the present study, we observed Le. lainsoni DNA in females of Ny. richardwardi for the first time. The data presented in this study contribute to understanding sand fly diversity and its distribution between the states of Rondônia and Amazonas. They may be useful for implementing targeted control measures to reduce the spread of leishmaniasis and implement entomological surveillance strategies.

Updating the knowledge of sand flies (Diptera, Psychodidae) in Rondônia State, Brazil

Background

Sandflies are insects important for the transmission cycles of the leishmaniases. Despite being studied since the 1960s in the State of Rondônia (Brazil), several gaps exist regarding our working knowledge of these insects. This study aimed to construct an up-to-date database of sandflies using complementary information from the speciesLink database and the scientific literature, as well as to elaborate integrated abundance maps. We identified 153,155 records of sandflies captured in Rondônia between 1965-2021; after exclusion, 147,258 reports (speciesLink - 3,408, Rondônia studies - 143,850) associated with 15 genera and 140 species were mapped. The most abundant species observed were Psychodopygusdavisi (Root, 1934) (43,818 records), Nyssomyiawhitmani (Antunes & Coutinho, 1939) (12,594), Psychodopyguscarrerai (Barretto, 1946) (11,840), Psychodopygushirsutus (Mangabeira, 1942) (9,676), Nyssomyiaantunesi (Coutinho, 1939) (8,847), Trichophoromyiaubiquitalis (Mangabeira, 1942) (5,505), Psychodopygusgeniculatus (Mangabeira, 1941) (4,644), Pintomyianevesi (Damasceno & Arouck, 1956) (4,140), Trichophoromyiaauraensis (Mangabeira, 1942) (3,579), Psychodopyguscomplexus (Mangabeira, 1941) (2,659), Nyssomyiafraihai (Martins, Falcão & Silva, 1979) (2,504) and Bichromomyiaflaviscutellata (Mangabeira, 1942) (1,418). A total of 20 records of Leishmania detection corresponded to eight sand fly species. The present dataset provides updated information on the distribution of sandflies of Rondônia, including those considered potential vectors of Leishmania, which should prove useful to guide future studies.

New information

The present study provides an extensive dataset built from all studies reporting phlebotomine sandflies in the Brazilian State of Rondônia. Online distribution maps can aid scientists who wish to consult the updated list of sand fly species and view the distribution of these insects, as well as those considered potential vectors of Leishmania. The results of the present study can serve as the basis for future studies on sandflies conducted in the State.

Entomological survey of phlebotominae sand flies (diptera: psychodidae) and vector species in the tegumentary leishmaniasis endemic area in eastern brazilian Amazon, Amapá state

Abstract: American tegumentary leishmaniasis is an endemic that has increased considerably in recent decades in the Amazon region, sand flies are the vectors of the transmission of the protozoan that causes leishmaniasis, so the objective of this study was to carry out a survey of the diversity of species and the presence of Leishmania DNA in vectors circulating in three endemic counties for tegumentary leishmaniasis in the eastern Brazilian Amazon (Amapá state, Brazil). Using CDC light traps, a total of 10,773 specimens were collected between February 2019 and February 2020, representing 64 species in 15 genera. The vector specie Nyssomyia umbratilis Ward and Frahia, 1977 was the predominant species (13.20% of the total), being collected in all three counties, followed by Trichopygomyia trichopyga Floch & Abonnenc, 1945 (11.41%), Trichophoromyia ubiquitalis Mangabeira,1942 (9.47%) and Nyssomyia anduzei Rozeboom, 1942 (7.61%). For the identification of Leishmania DNA, 775 pools of unengorged females were used, of which 5 tested positive, 2 of Nyssomya umbratilis Ward & Fraiha,1977, 1 of Nyssomyia anduzei and 2 of Psychodopygus davisi Root,1934, demonstrating a natural total infection rate of 0.64%. This study increases the knowledge of vector diversity, as well as identifying Leishmania spp. in circulation in the eastern region of the Amazon.

Multiple evolutionary lineages for the main vector of Leishmania guyanensis, Lutzomyia umbratilis (Diptera: Psychodidae), in the Brazilian Amazon

Lutzomyia umbratilis is the main vector of Leishmania guyanensis in the Brazilian Amazon and in neighboring countries. Previous biological and molecular investigations have revealed significant differences between L. umbratilis populations from the central Brazilian Amazon region. Here, a phylogeographic survey of L. umbratilis populations collected from nine localities in the Brazilian Amazon was conducted using two mitochondrial genes. Statistical analyses focused on population genetics, phylogenetic relationships and species delimitations. COI genetic diversity was very high, whereas Cytb diversity was moderate. COI genealogical haplotypes, population structure and phylogenetic analyses identified a deep genetic differentiation and three main genetic groups. Cytb showed a shallower genetic structure, two main haplogroups and poorly resolved phylogenetic trees. These findings, allied to absence of isolation by distance, support the hypothesis that the Amazon and Negro Rivers and interfluves are the main evolutionary forces driving L. umbratilis diversification. The main three genetic groups observed represent three evolutionary lineages, possibly species. The first lineage occurs north of the Amazon River and east of Negro River, where Le. guyanensis transmission is intense, implying that L. umbratilis is an important vector there. The second lineage is in the interfluve between north of Amazon River and west of Negro River, an area reported to be free of Le. guyanensis transmission. The third lineage, first recorded in this study, is in the interfluve between south of Amazonas River and west of Madeira River, and its involvement in the transmission of this parasite remains to be elucidated.

Detection of Leishmania DNA in Sand Flies (Diptera: Psychodidae) From a Cutaneous Leishmaniasis Outbreak Area in Northeastern Brazil

Cutaneous leishmaniasis (CL) by Leishmania braziliensis Vianna (Kinetoplastida: Trypanosomatidae) is a widespread disease in the western hemisphere and Brazil is the country reporting the majority of the human cases each year. Several phlebotomine sand flies have been regarded as putative or proven vectors of L. braziliensis and multiple vectors may be involved in the transmission of this parasite in the same endemic foci. In this study, we tested a subset of female phlebotomine sand flies collected in the frame of a previous study conducted in a military training camp, where outbreaks of CL by L. braziliensis have sporadically been reported. In total, 1,807 female phlebotomine sand flies were tested (individually or in pools) by real-time PCR and a minimum infection rate of 0.9% (95% CI: 0.6-1.5%) was detected. Positive females belonged to the species Psychodopygus complexus (Mangabeira) or Psychodopygus wellcomei Fraiha, Shaw & Lainson (females of these species are morphologically indistinguishable), Trichopygomyia longispina (Mangabeira), and Sciopemyia sordellii (Shannon & Del Ponte) (Diptera: Psychodidae). By restriction enzyme analysis, 13 samples (nine of Ty. longispina, two of Ps. complexus/wellcomei, and two of Sc. sordellii) presented a HaeIII restriction profile identical to L. braziliensis. The results of this study reinforce the notion that multiple vectors may be involved in the transmission of L. braziliensis in a single focus, ultimately making the epidemiological picture more complex than currently recognized.

New Records of Phlebotomine Sand Flies (Diptera: Psychodidae) From the State of Alagoas, Northeast of Brazil

Phlebotomine sand flies are small insects of great medical importance. This study presents new records of phlebotomine sand flies, which augment the list of species, recorded in the state of Alagoas, Brazil. Sand flies were collected using CDC miniature light traps. Collections were made between November 2008 and April 2016, in 47 municipalities within the state of Alagoas. Twenty-seven thousand two-hundred forty-four sand flies were collected, representing 18 species in seven genera. Lutzomyia longipalpis was the predominant species (85.4% of total), and it was recorded in all biomes. Three species (Evandromyia evandroi (Costa Lima and Antunes 1936), Evandromyia tupynambai (Mangabeira 1942), and Pressatia choti (Floch and Abonnenc 1941)) were collected in coastal and Atlantic forest biomes; five species (Lutzomyia villelai (Mangabeira 1942), Micropygomyia oswaldoi (Mangabeira 1942), Nyssomyia umbratilis (Ward and Frahia 1977), Nyssomyia intermedia (Lutz and Neiva 1912), and Nyssomyia whitmani (Antunes and Coutinho 1939)) were collected in Atlantic forest and Caatinga biomes. The species Evandromyia corumbaensis (Galati, Nunes, Oshiro and Rego 1989) and Psathyromyia naftalekatzi (Falcão, Andrade-Filho, Almeida and Brandão-Filho 2000) were found only in the coastal zones. This work provides an updated list of the phlebotomine sand flies of Alagoas, with some notes on their taxonomy, ecology, distribution, and epidemiological relevance.

Attractiveness of black and white modified Shannon traps to phlebotomine sandflies (Diptera, Psychodidae) in the Brazilian Amazon Basin, an area of intense transmission of American cutaneous leishmaniasis

In the Amazon region the phlebotomine fauna is considered one of the most diverse in the world. The use of Shannon traps may provide information on the anthropophily of the species and improve the traps' performance in terms of diversity and quantity of insects collected when white and black colored traps are used together. This study sought to verify the attractiveness of the traps to the phlebotomine species of the Brazilian Amazon basin using Shannon traps under these conditions. The insects were collected using two Shannon traps installed side by side, one white and the other black, in a primary forest area of the municipality of Xapuri, Acre, Brazil. Samples were collected once a month during the period August 2013 to July 2015. A sample of females was dissected to test for natural infection by flagellates. A total of 6,309 (864 males and 5,445 females) specimens (36 species) were collected. Psychodopygus carrerai carrerai (42%), Nyssomyia shawi (36%), and Psychodopygus davisi (13%), together represented 90% of the insects collected. Nyssomyia shawi and Psychodopygus davisi were more attracted by the white color. Specimens of Nyssomyia shawi, Nyssomyia whitmani, and Psychodopygus hirsutus hirsutus were found naturally infected by flagellates in the mid and hindgut. This is the first study in Acre state using and comparing both black and white Shannon traps, demonstrating the richness, diversity, and anthropophilic behavior of the phlebotomine species and identifying proven and putative vectors of the etiological agents of leishmaniasis.

Phlebotomine Sand Fly Composition (Diptera: Psychodidae) and Putative Vectors of American Cutaneous Leishmaniasis in Porto Velho Municipality, Western Amazon, Brazil

This study evaluated the species composition of sand flies and identified potential vectors of Leishmania Ross species in rural areas of Porto Velho, Rondônia State, Brazil. American cutaneous leishmaniasis (ACL) is one of the gravest threats to public health in this state. Sand flies were collected over the course of 2014 and 2015 using HP light traps. Polymerase chain reaction was performed by targeting the Leishmania mkDNA region. In total, 2,344 sand flies were collected, from which 45 species, nine subgenera, and five species group were identified. The most abundant species were Lutzomyia antunesi (Coutinho) (n = 597, 25.47%), Lutzomyia ubiquitalis (Mangabeira) (n = 496, 21.16%), and Lutzomyia octavioi (Vargas) (n = 199, 8.49%). The greatest diversity occurred in the forest environment where the most abundant species were L. antunesi (n = 588, 25.07%), L. ubiquitalis (n = 493, 21.02%), L. octavioi (n = 199, 8.49%), and Lutzomyia flaviscutellata (Mangabeira) (n = 132, 5.63%). Two pools of L. ubiquitalis were positive for Leishmania DNA, which suggests that L. ubiquitalis is a putative vector of leishmaniasis in the municipality of Porto Velho.

Sandfly fauna (Diptera: Psychodidae) from caves in the state of Rondônia, Brazil

This study had the aim of ascertaining the sandfly fauna and possible presence of Leishmania in these insects, collected in caves in the state of Rondônia, Brazil. Collections were conducted in eight caves located in two different areas of this state. Leishmania in the sandflies collected was detected using the polymerase chain reaction (PCR). This was the first study on sandflies from caves in Rondônia and, among the total of 1,236 individuals collected, 24 species and 10 genera were identified. The species Evandromyia georgii was collected for the first time in Rondônia and the most abundant species were Trichophoromyia ubiquitalis with 448 individuals (36.2%), followed by T. octavioi with 283 (22.9%) and E. georgii with 179 (14.5%). For the PCR, 17 pools were analyzed and five pools were positive (forT. auraensis in three pools and for Nyssomyia shawi and N. antunesi in one pool each). The kDNA region was amplified and the presence of Leishmania DNA was confirmed. The sandfly fauna in these caves can be considered diverse in comparison with similar studies in other regions. It may be that some species use caves as a temporary shelter and breeding site, while other species live exclusively in this environment. The detection of Leishmania DNA indicates that this pathogen is circulating in cave environments and that further studies are needed in order to ascertain the risks of infection by leishmaniasis in these locations with high touristic potential.

Ecological aspects and molecular detection of Leishmania DNA Ross (Kinetoplastida: Trypanosomatidae) in phlebotomine sandflies (Diptera: Psychodidae) in terra firme and várzea environments in the Middle Solimões Region, Amazonas State, Brazil

Background

Phlebotomine sand flies (Diptera: Psychodidae) are insects of medical importance due to the role that some species play in the transmission of leishmaniasis. This work aimed to study some ecological aspects among sand flies fauna inhabiting two different environments: the várzea (lowland Amazonian forest) and terra firme (upland Amazonian forest), both located in Tefé Municipality, Amazonas State, Braziland to detect Leishmania infection in those phlebotomine populations.

Methods

Sand flies were collected using HP light traps. Collection took place over the course of six months: January, February, April, August, September, and October of 2013. To detect natural infection by Leishmania, DNA samples were extracted from female sand flies and submitted to Polymerase Chain Reaction (PCR) targeting the kDNA gene; Leishmania species were identified by PCR-RFLP targeting the hsp70 gene and genetic sequencing.

Results

In all, 5,716 individuals were collected, and 46 species were identified. Trichophoromyia ubiquitalis (3,330 – 58.26%) and Nyssomyia antunesi (661 – 11.26%) were the most abundant species. Species richness was greater in terra firme environments (42 species) than in the várzea environments (22 species), and forests ecotopes (43 species) were richer than peridomiciles (28 species). DNA of Leishmania was found in Th. ubiquitalis and Psychodopygus davisi, both of which inhabit the terra firme environment and sequencing analysis confirmed the presence of Leishmania (Viannia) lainsoni DNA in Th. ubiquitalis in Tefé Municipality.

Conclusions

The high abundance of Th. ubiquitalis and Ps. davisi and detection of DNA of Leishmania sp. may indicate that both species could be putative vectors for American Cutaneous Leishmaniasis (ACL) in the terra firme environment of Tefé. The sand fly fauna found in várzea is rich and diverse, exhibiting several species, nevertheless the seasonal hydric stress during part of the year that could influence the local diversity, if compared with other studies. This is the first report in Amazonas State of Th. ubiquitalis with presence of L. (V.) lainsoni DNA.

Molecular taxonomy of the two Leishmania vectors Lutzomyia umbratilis and Lutzomyia anduzei (Diptera: Psychodidae) from the Brazilian Amazon

BACKGROUND

Lutzomyia umbratilis (a probable species complex) is the main vector of Leishmania guyanensis in the northern region of Brazil. Lutzomyia anduzei has been implicated as a secondary vector of this parasite. These species are closely related and exhibit high morphological similarity in the adult stage; therefore, they have been wrongly identified, both in the past and in the present. This shows the need for employing integrated taxonomy.

METHODS

With the aim of gathering information on the molecular taxonomy and evolutionary relationships of these two vectors, 118 sequences of 663 base pairs (barcode region of the mitochondrial DNA cytochrome oxidase I - COI) were generated from 72 L. umbratilis and 46 L. anduzei individuals captured, respectively, in six and five localities of the Brazilian Amazon. The efficiency of the barcode region to differentiate the L. umbratilis lineages I and II was also evaluated. The data were analyzed using the pairwise genetic distances matrix and the Neighbor-Joining (NJ) tree, both based on the Kimura Two Parameter (K2P) evolutionary model.

RESULTS

The analyses resulted in 67 haplotypes: 32 for L. umbratilis and 35 for L. anduzei. The mean intra-specific genetic distance was 0.008 (0.002 to 0.010 for L. umbratilis; 0.008 to 0.014 for L. anduzei), whereas the mean interspecific genetic distance was 0.044 (0.041 to 0.046), supporting the barcoding gap. Between the L. umbratilis lineages I and II, it was 0.009 to 0.010. The NJ tree analysis strongly supported monophyletic clades for both L. umbratilis and L. anduzei, whereas the L. umbratilis lineages I and II formed two poorly supported monophyletic subclades.

CONCLUSIONS

The barcode region clearly separated the two species and may therefore constitute a valuable tool in the identification of the sand fly vectors of Leishmania in endemic leishmaniasis areas. However, the barcode region had not enough power to separate the two lineages of L. umbratilis, likely reflecting incipient species that have not yet reached the status of distinct species.

Lutzomyia umbratilis, the main vector of Leishmania guyanensis, represents a novel species complex?

BACKGROUND

Lutzomyia umbratilis is an important Leishmania guyanensis vector in South America. Previous studies have suggested differences in the vector competence between L. umbratilis populations situated on opposite banks of the Amazonas and Negro Rivers in the central Amazonian Brazil region, likely indicating a species complex. However, few studies have been performed on these populations and the taxonomic status of L. umbratilis remains unclear.

METHODOLOGY/PRINCIPAL FINDINGS

Phylogeographic structure was estimated for six L. umbratilis samples from the central Amazonian region in Brazil by analyzing mtDNA using 1181 bp of the COI gene to assess whether the populations on opposite banks of these rivers consist of incipient or distinct species. The genetic diversity was fairly high and the results revealed two distinct clades ( = lineages) with 1% sequence divergence. Clade I consisted of four samples from the left bank of the Amazonas and Negro Rivers, whereas clade II comprised two samples from the right bank of Negro River. No haplotypes were shared between samples of two clades. Samples within clades exhibited low to moderate genetic differentiation (F(ST) = -0.0390-0.1841), whereas samples between clades exhibited very high differentiation (F(ST) = 0.7100-0.8497) and fixed differences. These lineages have diverged approximately 0.22 Mya in the middle Pleistocene. Demographic expansion was detected for the lineages I and II approximately 30,448 and 15,859 years ago, respectively, in the late Pleistocene.

CONCLUSIONS/SIGNIFICANCE

The two genetic lineages may represent an advanced speciation stage suggestive of incipient or distinct species within L. umbratilis. These findings suggest that the Amazonas and Negro Rivers may be acting as effective barriers, thus preventing gene flow between populations on opposite sides. Such findings have important implications for epidemiological studies, especially those related to vector competence and anthropophily, and for vector control strategies. In addition, L. umbratilis represents an interesting example in speciation studies.