American Cutaneous Leishmaniasis Vectors Research Articles

Fauna of phlebotomine sand flies (Diptera, Psychodidae) in areas with endemic American cutaneous leishmaniasis in the State of Mato Grosso do Sul, Brazil

Fauna of phlebotomine sand flies (Diptera, Psychodidae) in areas with endemic American cutaneous leishmaniasis in the State of Mato Grosso do Sul, Brazil. The aim of this study was to investigate the ecological aspects of the main vectors of American cutaneous leishmaniasis (ACL) in four monitoring stations situated in the municipalities of Naviraí, Nova Andradina, Novo Horizonte do Sul and Rio Verde de Mato Grosso. For each monitoring station, the captures of sand flies were undertaken each month from July 2008 to June 2010 using CDC and Shannon traps. The CDC traps were installed simultaneously for three consecutive nights in three collection sites: intradomicile, peridomicile and edge of the forest. A Shannon trap was installed from dusk to 10 pm, inside the forest, one night per month. A total of 7,651 sand flies belonging to nine genera and twenty-nine species were captured. Nyssomyia neivai (52.95%), Psathyromyia hermanlenti (10.91%), Psathyromyia runoides (9.16%), Nyssomyia whitmani (7.95%), Psathyromyia aragaoi (4. 89%), Nyssomyia antunesi (3.14%) and Evandromyia bourrouli (2.20%) were the most frequent species. Approximately 65% of the sand flies were collected in the forest environment. The municipalities presented significantly different indexes of species diversity. Naviraí presented the lowest species diversity index, however, it showed the highest abundance. Novo Horizonte do Sul had the highest species diversity index, but the lowest abundance (< 5%). It is noteworthy the occurrence of vector species of Leishmania in the areas studied, especially in Naviraí, where Ny. neivai presented high frequencies which may explain the increased number of ACL cases in this municipality.

Attraction of the cutaneous leishmaniasis vector Nyssomyia neivai (Diptera: Psychodidae) to host odour components in a wind tunnel

BackgroundLaboratory studies of host-seeking olfactory behaviour in sandflies have largely been restricted to the American visceral leishmaniasis vector Lutzomyia longipalpis. In comparison, almost nothing is known about the chemical ecology of related species, which transmit American cutaneous leishmaniasis (ACL), due in part to difficulties in raising these insects in the laboratory. Understanding how ACL vectors locate their hosts will be essential to developing new vector control strategies to combat this debilitating disease.MethodsThis study examined host-odour seeking behaviour of the ACL vector Nyssomyia neivai (Pinto) (=Lutzomyia neivai) using a wind tunnel olfactometer. The primary aim was to determine whether field-collected female N. neivai would respond to host odours in the laboratory, thereby eliminating the need to maintain colonies of these insects for behavioural experiments. Responses to two key host odour components, 1-octen-3-ol and lactic acid, and a commercially-available mosquito lure (BG-Lure™) were assessed and compared relative to an air control. We also tested whether trials could be conducted outside of the normal evening activity period of N. neivai without impacting on fly behaviour, and whether the same flies could be used to assess baseline responses to air without affecting responses to octenol, thereby reducing the number of flies required for experiments.ResultsOctenol was found to both activate host-seeking behaviour and attract female N. neivai in the wind tunnel, while lactic acid elicited weaker responses of activation and attractiveness under identical conditions. The BG-Lure did not activate or attract N. neivai under test conditions. Further experiments showed that sandfly behaviour in the wind tunnel was not affected by time of day, such that experiments need not be restricted to nocturnal hours. Moreover, using the same flies to measure both baseline responses to air and attraction to test compounds did not affect odour-seeking behaviour.ConclusionsThe results of this study demonstrate that N. neivai taken from the field are suitable for use in laboratory olfactometer experiments. It is hoped this work will facilitate further research into chemical ecology of this species, and other ACL vectors.

Natural infection of cortelezzii complex (Diptera: Psychodidae: Phlebotominae) with Leishmania braziliensis in Chaco, Argentina

In Argentina, American Cutaneous Leishmaniasis (ACL) extends up to 29°S in the phytogeographic regions of the Yungas (west), Chaco (center) and Paranaense (east). Since the Phlebotominae vectors of this disease in the western Chaco (dry Chaco) are unknown, in the present work, we studied the natural infection in Phlebotominae by PCR-ERFLP and Dot blot in order to incriminate these organisms as potential vectors. Captures with CDC-type traps were performed monthly in the domicile, the peridomicile and the forest in the Municipio Misión Nueva Pompeya, Chaco, Argentina, in two sites with human cases of ACL: Los Pozos (24°54′S, 61°22′W) and Fortín Arenales (24°58′S, 61°21′W), from November 2006 to December 2007. A total of 1702 Phlebotominae were captured: Mygonemyia migonei (83.8%), cortelezzii complex (11.1%), Mycropigomyia peresi (3.3%), Mycropygomy quinquefer (1.2%), Pintomyia torresi (0.2%) and Nyssomyia neivai (0.2%). Although no significant differences were found in species diversity, there were significant differences in abundance between both sites studied. A total of 80 phlebotomine females were analyzed: 50 of the cortelezzii complex and 30 My. migonei. No intestinal flagellates were observed by light microscopy. Two pools of 10 individuals of the cortelezzii complex of the peridomicile and forest of Fortín Arenales were reactive by PCR and Dot blot for Leishmania (Viannia) braziliensis. In Argentina, Evandromyia cortelezzii has been incriminated as a likely vector of ACL because of its abundance in areas of sporadic outbreaks. In the present work, Ev. cortelezzii females were found naturally infected, thus reinforcing the hypothesis that the members of the cortelezzii complex act as vectors of the disease.

Phlebotomine Fauna (Diptera: Psychodidae) and Putative Vectors of Leishmaniases in Impacted Area by Hydroelectric Plant, State of Tocantins, Brazil

BackgroundAlthough leishmaniases are regarded as serious public health issues in the State of Tocantins, as consequence of the impact of environmental changes, small advances in taxonomic and ecological studies of Phlebotominae fauna are taking place in this state. The present study aimed to improve the knowledge about the sand flies, as well as about the aspects of the bioecology of leishmaniases vectors from Porto Nacional, a city that was directly impacted by the construction of Luís Eduardo Magalhães Hydroelectric Plant (HEP – Lajeado).Methodology/Principal FindingsSand flies were collected monthly using CDC light traps and Shannon traps for a period of 40 consecutive months, at different monitoring stations, where 7162 specimens were collected and 48 species were detected. Among the species found, 22 are first records in the state and seven are considered important vectors of leishmaniases. Lutzomyia longipalpis, the vector of American Visceral Leishmaniasis (AVL) showed higher frequency in urban compared to rural areas, and Nyssomyia whitmani, the vector of American Cutaneous Leishmaniasis (ACL), predominated in rural areas. The frequency and habits of sand fly vectors are discussed considering environmental characteristics and climatic factors.Conclusions/SignificanceThe construction of dams requires a great amount of labor, therefore attracting people from elsewhere. Increased migration, without adequate structure, leads to bad living conditions in new and unplanned settlements. It also leads to deforestation associated with environmental impacts, which can facilitate the spread of leishmaniases.This study discusses the importance of Lu. longipalpis and Ny. whitmani on the transmission cycles of leishmaniases in Porto Nacional and the record of Bi. flaviscutellata in periurban area of the city.

Anthropogenic influence on the distribution, abundance and diversity of sandfly species (Diptera: Phlebotominae: Psychodidae), vectors of cutaneous leishmaniasis in Panama

In Panama, species of the genus Lutzomyia are vectors of American cutaneous leishmaniasis (ACL). There is no recent ecological information that may be used to develop tools for the control of this disease. Thus, the goal of this study was to determine the composition, distribution and diversity of Lutzomyia species that serve as vectors of ACL. Sandfly sampling was conducted in forests, fragmented forests and rural environments, in locations with records of ACL. Lutzomyia gomezi, Lutzomyia panamensis and Lutzomyia trapidoi were the most widely distributed and prevalent species. Analysis of each sampling point showed that the species abundance and diversity were greatest at points located in the fragmented forest landscape. However, when the samples were grouped according to the landscape characteristics of the locations, there was a greater diversity of species in the rural environment locations. The Kruskal Wallis analysis of species abundance found that Lu. gomezi and Lu. trapidoi were associated with fragmented environments, while Lu. panamensis, Lutzomyia olmeca bicolor and Lutzomyia ylephiletor were associated with forested environments. Therefore, we suggest that human activity influences the distribution, composition and diversity of the vector species responsible for leishmaniasis in Panama.

Lutzomyia (Pintomyia) fischeri (Diptera: Psychodidae: Phlebotominae), a probable vector of American Cutaneous Leishmaniasis: Detection of natural infection by Leishmania (Viannia) DNA in specimens from the municipality of Porto Alegre (RS), Brazil, using multiplex PCR assay

In order to determine natural Leishmania (Viannia) infection in Lutzomyia (Pintomyia) fischeri, a multiplex PCR methodology coupled to non-isotopic hybridization was adopted for the analysis of sand fly samples collected by CDC light traps in an endemic area of American Cutaneous Leishmaniasis (ACL) in the periurban region of the municipality of Porto Alegre, Rio Grande do Sul State, Brazil. We analyzed by PCR methodology 560 specimens of Lutzomyia (Pintomyia) fischeri (520 females and 40 males). The wild sand flies were grouped into 56 pools (52 females and 4 males) of 10 each, and positive results were detected in 2 of the 52 female pools, representing a minimum infection rate of 0.38% based on the presence of at least 1 infected insect in the pool. This result associated with some local evidence such as anthopophily, spatial distribution in accordance with the transmission area and human case incidence, suggests that L. (P.)fischeri may be considered as a secondary vector of ACL in the studied locality.

Phylogenetics of the Phlebotomine Sand Fly Group Verrucarum (Diptera: Psychodidae: Lutzomyia)

Within the sand fly genus Lutzomyia, the Verrucarum species group contains several of the principal vectors of American cutaneous leishmaniasis and human bartonellosis in the Andean region of South America. The group encompasses 40 species for which the taxonomic status, phylogenetic relationships, and role of each species in disease transmission remain unresolved. Mitochondrial cytochrome c oxidase I (COI) phylogenetic analysis of a 667-bp fragment supported the morphological classification of the Verrucarum group into series. Genetic sequences from seven species were grouped in well-supported monophyletic lineages. Four species, however, clustered in two paraphyletic lineages that indicate conspecificity—the Lutzomyia longiflocosa–Lutzomyia sauroida pair and the Lutzomyia quasitownsendi–Lutzomyia torvida pair. COI sequences were also evaluated as a taxonomic tool based on interspecific genetic variability within the Verrucarum group and the intraspecific variability of one of its members, Lutzomyia verrucarum, across its known distribution.

Spatial and temporal patterns of occurrence of Lutzomyia sand fly species in an endemic area for cutaneous leishmaniasis in the Atlantic Forest region of northeast Brazil

Sand fly populations of different ecological niches in the Amaraji endemic American Cutaneous Leishmaniasis (ACL) focus of the Pernambuco Atlantic Forest region of northeastern Brazil were monitored spatiotemporally. Lutzomyia whitmani was dominant in all niches but occurred in smaller numbers in forested locations. L. whitmani was significantly less seasonal than the other species, being present throughout the year while other species were more abundant between February and April. These results suggest that L. whitmani may potentially be the principal vector of ACL in the region, even though the sand fly fauna was diverse: 88% were L.whitmani and 12% belonged to 11 other species. Two other species, L. complexa (1.3%) and L. migonei (0.8%), considered to be ACL vectors in other regions, were also present. This detailed picture of the sand fly population's abundance and spatiotemporal distribution provides a basis for future modeling studies of forecasting sand fly activity patterns and ACL occurrence.

Geographical distribution of American cutaneous leishmaniasis and its phlebotomine vectors (Diptera: Psychodidae) in the state of São Paulo, Brazil

BackgroundAmerican cutaneous leishmaniasis (ACL) is a re-emerging disease in the state of São Paulo, Brazil. It is important to understand both the vector and disease distribution to help design control strategies. As an initial step in applying geographic information systems (GIS) and remote sensing (RS) tools to map disease-risk, the objectives of the present work were to: (i) produce a single database of species distributions of the sand fly vectors in the state of São Paulo, (ii) create combined distributional maps of both the incidence of ACL and its sand fly vectors, and (iii) thereby provide individual municipalities with a source of reference material for work carried out in their area.ResultsA database containing 910 individual records of sand fly occurrence in the state of São Paulo, from 37 different sources, was compiled. These records date from between 1943 to 2009, and describe the presence of at least one of the six incriminated or suspected sand fly vector species in 183/645 (28.4%) municipalities. For the remaining 462 (71.6%) municipalities, we were unable to locate records of any of the six incriminated or suspected sand fly vector species (Nyssomyia intermedia, N. neivai, N. whitmani, Pintomyia fischeri, P. pessoai and Migonemyia migonei). The distribution of each of the six incriminated or suspected vector species of ACL in the state of São Paulo were individually mapped and overlaid on the incidence of ACL for the period 1993 to 1995 and 1998 to 2007. Overall, the maps reveal that the six sand fly vector species analyzed have unique and heterogeneous, although often overlapping, distributions. Several sand fly species - Nyssomyia intermedia and N. neivai - are highly localized, while the other sand fly species - N. whitmani, M. migonei, P. fischeri and P. pessoai - are much more broadly distributed. ACL has been reported in 160/183 (87.4%) of the municipalities with records for at least one of the six incriminated or suspected sand fly vector species, while there are no records of any of these sand fly species in 318/478 (66.5%) municipalities with ACL.ConclusionsThe maps produced in this work provide basic data on the distribution of the six incriminated or suspected sand fly vectors of ACL in the state of São Paulo, and highlight the complex and geographically heterogeneous pattern of ACL transmission in the region. Further studies are required to clarify the role of each of the six suspected sand fly vector species in different regions of the state of São Paulo, especially in the majority of municipalities where ACL is present but sand fly vectors have not yet been identified.

Fauna flebotomínica da Serra dos Carajás, Estado do Pará, Brasil, e sua possível implicação na transmissão da leishmaniose tegumentar americana

Serra dos Carajas, located in the southeast of Para State, Brazil, is a rich tropical forest where species of Leishmania sp. of medical interest are found, such as Leishmania (V.) braziliensis, L. (V.) lainsoni, L. (V.) shawi and L. (L.) amazonensis. They are transmitted by the following phlebotomi: Psychodopygus complexus or Ps. wellcomei, Lutzomyia ubiquitalis, Lu. whitmani and Lu. flaviscutellata. Considering the increase of immigrants in the region of the Carajas project, this study aimed to assess the Phlebotominae fauna and their possible participation in the transmission of American cutaneous leishmaniasis (ACL). The phlebotomi were captured from December 2005 to September 2007 at the following locations: i) Parauapebas Botanical Park; ii) an environmental protection area; and iii) Tapirape-Aquiri National Forest. During the 172 days of collection, 10 CDC (18 h to 6 h) and 2 Shannon (18 h to 20 h) light traps were used. Of the 22,095 phlebotomi captured, 6,789 (31%) were male and 15,306 (69%) were female, and they belonged to 69 species and three genera, including Psychodopygus, Lutzomyia and Brumptomyia. A total of 19 (0.16%) natural infections of the following species were detected: Ps. davisi (4), Ps. h. hirsutus (3), Lu. umbratilis (3), Lu. richardward (2), Lu. brachipyga (2), Lu. ubiquitalis (2), Lu. trinidadensis (1) and Lu. migonei (1). Although no infection was found in Ps. wellcomei/complexus, the main vector of L. (V.) braziliensis in the region, this species was the most prevalent (16%), followed by Ps. davisi (15.4%), Ps. carrerai (4.2%), Lu. shawi (3.9%), Lu. brachipyga (2.5%) and Lu. richardward (1.2%). These results show the importance of these phlebotomi as possible vectors of ACL in Serra dos Carajas.

The Vectorial Potential ofLutzomyia (Nyssomyia) intermediaandLutzomyia (N.) whitmaniin the Transmission ofLeishmania (V.) braziliensisCan Also Be Related to Proteins Attaching

We read with great interest the report by Soares et al. [1] on the potential of Leishmania (Viannia) braziliensis to attach to the midgut of the sand flies Lutzomyia (N.) whitmani and Lutzomyia (N.) intermedia. This manuscript assesses relevant information concerning the biomolecular phenomena between Leishmania promastigotes and the midgut of Lutzomyia species that act as vectors of American Cutaneous Leishmaniasis (ACL). However, it is necessary to comment that the basis of these physiological processes is not directly driven by glycolipid lipophosphoglycan (LPG) only. Other L. (V.) braziliensis promastigotes surface components, as proteins, can also be implicated in many steps of the midgut attachment. Since 2007 we have been investigating the potential of heparin binding proteins (HPBs) from L. (V.) braziliensis promastigotes in the attachment of parasites to gut proteins from L. (N.) intermedia and L. (N.) whitmani [2]. We have indicated the existence of physicochemical conditions for the binding between the gut proteins from Lutzomyia spp. and the HPBs—a new macromolecule class involved in the recognition of the sand fly gut epithelium by L. (V.) braziliensis. We proposed that the five HPB ligands (67.0, 62.1, 59.5, 56.0, and 47.5 kDa) observed in both L. (N.) intermedia and L. (N.) whitmani are involved with the promastigote attachments to sand fly gut epithelium. Also, we suggested that the physicochemical conditions for the interaction between HBP and their ligands are more favourable in the midgut of L. (N.) whitmani than in L. (N.) intermedia. Furthermore, heparin similar molecules, synthesized by cells of midgut epithelium seem to act as anchoring sites for L. (V.) braziliensis promastigotes. The ability of promastigotes to adhere to epithelial microvillii of the Phlebotominae digestorium tube is an essential stage for the maintenance of the parasite life cycle, being a factor of distinction between infective and noninfective stains. Similarly to LPG, the HBPs are related to the infective forms of the parasite [3, 4]. In such a way, its presence can be an essential factor for the setting of promastigotes in the digestorium tube and for the continuity of the life cycle, since parasites unable to adhere to the intestinal epithelium would be rejected together with the “feces” of the insect vector [5]. In addition, L. (N.) intermedia and L. (N.) whitmani are related to L. (V.) braziliensis transmission in the same endemic area [6]. The detection of ligands with similar molecular weights in the digestorium tube of both insect species is a biochemical indicative of vectorial homogeneity of these species in the transmission of ACL. The mapping of the interactions between molecules from both parasite and vector molecules can help in the understanding of adhesion to epithelial cells through the parasite surface. Thus, our results considered together with the recent findings by Soares et al. [1] present biochemical indicatives of the epidemiological relevance of L. (N.) whitmani as a primary vector of ACL in Brazil.

Differential Midgut Attachment ofLeishmania (Viannia) braziliensisin the Sand FliesLutzomyia (Nyssomyia) whitmaniandLutzomyia (Nyssomyia) intermedia

The interaction between Leishmania and sand flies has been demonstrated in many Old and New World species. Besides the morphological differentiation from procyclic to infective metacyclic promastigotes, the parasite undergoes biochemical transformations in its major surface lipophosphoglycan (LPG). An upregulation of β-glucose residues was previously shown in the LPG repeat units from procyclic to metacyclic phase in Leishmania (Viannia) braziliensis, which has not been reported in any Leishmania species. LPG has been implicated as an adhesion molecule that mediates the interaction with the midgut epithelium of the sand fly in the Subgenus Leishmania. These adaptations were explored for the first time in a species from the Subgenus Viannia, L. (V.) braziliensis with its natural vectors Lutzomyia (Nyssomyia) intermedia and Lutzomyia (Nyssomyia) whitmani. Using two in vitro binding techniques, phosphoglycans (PGs) derived from procyclic and metacyclic parasites were able to bind to the insect midgut and inhibit L. braziliensis attachment. Interestingly, L. braziliensis procyclic parasite attachment was ∼11-fold greater in the midgut of L. whitmani than in L. intermedia. The epidemiological relevance of L. whitmani as a vector of American Cutaneous Leishmaniasis (ACL) in Brazil is discussed.

Proven and putative vectors of American cutaneous leishmaniasis in Brazil: aspects of their biology and vectorial competence

The aim of the present review is to give relevant information on aspects of the biology and ecology, including the vectorial competence of Lutzomyia sand fly species suggested as vectors of American cutaneous leishmaniasis in Brazil. The disease, due to Leishmania (Viannia) braziliensis, has been registered in most municipalities in all the Brazilian states and its transmission is associated with more than one sand fly species in each geographical region. A variety of Leishmania species can be found in the Amazon basin, where different epidemiological chains have been detected with the participation of different phlebotomine vectors. Finally, a discussion is presented on some sand fly species found naturally infected by Leishmania, but for which there is as yet no evidence regarding their epidemiological importance.

American cutaneous leishmaniasis in the Pontal of Paranapanema - SP, Brazil: ecological and entomological aspects

American cutaneous leishmaniasis (ACL) occurs in epidemic outbreaks and in sporadic cases with small annual variation in the Pontal of Paranapanema, SP. There is little research on the sandfly fauna of this region. The last outbreaks were related to the Movement of the Landless Workers (MST) and with the ecological tourism in preserved forest of the Parque Estadual do Morro do Diabo (PEMD). identification of the sandfly fauna within the PEMD, mainly anthropophilic species already incriminated as vectors of ACL, as well as their seasonality, hourly frequency and data of the behavior. M&M: The captures were undertaken with CDC light and Shannon traps from 6:00 pm to 10:00 pm, monthly from May 2000 to December 2001. The temperature and relative humidity data were registered at hourly intervals. The captured species were: Brumptomyia brumpti, Nyssomyia neivai, Nyssomyia whitmani, Pintomyia fischeri and Pintomyia pessoai. The P. pessoai predominated (34.39%) and N. neivai was less found (0.74%), only being captured in CDC traps. Shannon trap captured more sandflies (63.01%) than the CDC traps (36.99%). Despite the environmental degradation anthropophilic species, indicates favorable bioecological conditions for persistence of vectors and potential transmission of leishmaniasis.

Multilocus analysis of introgression between two sand fly vectors of leishmaniasis

BackgroundThe phlebotomine sand flies (Diptera:Psychodidae) Lutzomyia (Nyssomyia) intermedia Lutz & Neiva 1912 and Lutzomyia (Nyssomyia) whitmani Antunes & Coutinho 1932 are two very closely related species and important vectors of American cutaneous leishmaniasis. Two single-locus studies have revealed evidence for introgression between the two species in both mitochondrial and nuclear genomes. These findings have prompted the development of a multilocus approach to investigate in more detail the genetic exchanges between the two species.ResultsWe analyzed ten nuclear loci using the "isolation with migration" model implemented in the IM program, finding evidence for introgression from L. intermedia towards L. whitmani in three loci. These results confirm that introgression is occurring between the two species and suggest variation in the effects of gene flow among the different regions of the genome.ConclusionThe demonstration that these two vectors are not fully reproductively isolated might have important epidemiological consequences as these species could be exchanging genes controlling aspects of their vectorial capacity.

Ultrastructural Comparison of External Morphology of Immature Stages of &lt;I&gt;Lutzomyia&lt;/I&gt; (&lt;I&gt;Nyssomyia&lt;/I&gt;) &lt;I&gt;intermedia&lt;/I&gt; and &lt;I&gt;Lutzomyia&lt;/I&gt; (&lt;I&gt;Nyssomyia&lt;/I&gt;) &lt;I&gt;whitmani&lt;/I&gt; (Diptera: Psychodidae), Vectors of Cutaneous Leishmaniasis, by Scanning Electron Microscopy

Lutzomyia (Nyssomyia) intermedia (Lutz & Neiva 1912) and Lutzomyia (Nyssomyia) whitmani (Antunes & Coutinho 1939) (Diptera: Psychodidae) are vectors of American cutaneous leishmaniasis in several endemic regions of Brazil. We analyzed the external morphological aspects of the immature stages of these two vectors by using scanning electron microscopy. In general, the larval stages of the two species are morphologically similar, although some differences were noted. Detailed examination of the eggs of both species revealed similar exchorionic ornamentations of unconnected parallel ridges. The larval head capsules are well defined, heavily sclerotized, and bear prominent chewing mouthparts. The abdominal segments are easily recognized by the presence of prolegs on their ventral surfaces. The morphology of the anal lobe on the terminal abdominal segment differs between the two species. We found the following three types of sensillae inserted on the antennae: (1) clavate basiconic; (2) small, blunt coeloconic; and (3) multipourous clavate coleoconic. In addition; five subtypes of trichoid sensillae were found on the larval body: (1) long, (2) short, (3) curved long, (4) brush-like, and (5) weakly brush-like. The caudal filaments located on the last abdominal segment were recognized as long trichoid sensillae. We observed pores on the surface of the clavate coelonic sensillae and on the caudal filaments that presumably function as chemoreceptors. The larvae of the two species show similarities in the lobular-form antennae of L1 larvae, which changes to digitiform in second instar (L2), L3, and L4. This study demonstrated that the external surface of the eggs and larvae of Lu. intermedia and Lu. whitmani are morphologically similar, but they can be distinguished by details in the microanatomy observed by scanning electron microscopy.

Ultrastructural Comparison of External Morphology of Immature Stages of Lutzomyia (Nyssomyia) intermedia and Lutzomyia (Nyssomyia) whitmani (Diptera: Psychodidae), Vectors of Cutaneous Leishmaniasis, by Scanning Electron Microscopy

Lutzomyia (Nyssomyia) intermedia (Lutz & Neiva 1912) and Lutzomyia (Nyssomyia) whitmani (Antunes & Coutinho 1939) (Diptera: Psychodidae) are vectors of American cutaneous leishmaniasis in several endemic regions of Brazil. We analyzed the external morphological aspects of the immature stages of these two vectors by using scanning electron microscopy. In general, the larval stages of the two species are morphologically similar, although some differences were noted. Detailed examination of the eggs of both species revealed similar exchorionic ornamentations of unconnected parallel ridges. The larval head capsules are well defined, heavily sclerotized, and bear prominent chewing mouthparts. The abdominal segments are easily recognized by the presence of prolegs on their ventral surfaces. The morphology of the anal lobe on the terminal abdominal segment differs between the two species. We found the following three types of sensillae inserted on the antennae: 1) clavate basiconic; 2) small, blunt coeloconic; and 3) multipourous clavate coleoconic. In addition; five subtypes of trichoid sensillae were found on the larval body: 1) long, 2) short, 3) curved long, 4) brush-like, and 5) weakly brush-like. The caudal filaments located on the last abdominal segment were recognized as long trichoid sensillae. We observed pores on the surface of the clavate coelonic sensillae and on the caudal filaments that presumably function as chemoreceptors. The larvae of the two species show similarities in the lobular-form antennae of L1 larvae, which changes to digitiform in second instar (L2), L3, and L4. This study demonstrated that the external surface of the eggs and larvae of Lu. intermedia and Lu. whitmani are morphologically similar, but they can be distinguished by details in the microanatomy observed by scanning electron microscopy.

Moonlight and blood-feeding behaviour of Lutzomyia intermedia and Lutzomyia whitmani (Diptera:Psychodidae:Phlebotominae), vectors of American cutaneous leishmaniasis in Brazil

Lutzomyia intermedia (Lutz & Neiva, 1912) and L. whitmani (Antunes & Coutinho, 1939) (Diptera: Psychodidae: Phlebotominae), two important vectors of American cutaneous leishmaniasis in Brazil, occur in sympatry in the locality of Posse county, Petropolis municipality, state of Rio de Janeiro, Brazil. We investigated the influence of the lunar cycle on the frequency of specimens of the two species caught while attempting to bite the collectors and in CDC light traps. Analysis of the numbers of sand flies captured in different lunar phases for two consecutive years in the peridomestic site and forest shows that there is a significant positive correlation between moonlight intensity and the numbers of L. intermedia and L. whitmani females collected while blood-feeding, whereas the opposite was observed for the CDC traps.

Sand-fly fauna (Díptera, psychodidae, phlebotominae) in Bolívar State, Venezuela

A descriptive study is presented of sand-fly fauna in Bolivar State, Venezuela. Identification was made of 2,364 sand-flies belonging to 18 species. The vectors of American cutaneous leishmaniasis in the different geographic regions of Bolivar State are possibly L. anduzei, L. wellcomei and L. squamiventris in the South, and L. flaviscutellata and L. gomezi in the North.

Is the domestic dog (Canis familiaris) a reservoir host of American cutaneous leishmaniasis? A critical review of the current evidence.

Originally associated with forested areas, the transmission cycle of American cutaneous leishmaniasis (ACL) has now adapted to the domestic environment in at least 9 Latin American countries. Several studies have suggested that the domestic dog (Canis familiaris), which is already incriminated as the primary reservoir host of zoonotic visceral leishmaniasis (ZVL), may have a reservoir role in the domestic transmission of human ACL caused by Leishmania braziliensis, L. panamensis, and L. peruviana. This article reviews more than 90 studies reporting ACL infections in dogs, and concludes that as yet there is only circumstantial evidence to support that claim. Almost no data are available on the infectiousness of dogs to sandfly vectors of ACL, and there are few indications that either dog ownership or dog abundance are risk factors for ACL. Nevertheless, it has been proposed that incidence of ACL in humans could be reduced by targeting infected dogs. While this control strategy has been used for many decades against ZVL in Latin America, Europe, and Asia, there is little evidence to demonstrate its effectiveness either in theory or in practice. Particular concerns over the sensitivity and specificity of diagnostic tools, low compliance rates among dog owners, and cost-effectiveness are likely to apply equally to ACL control.