Natural infection of Lutzomyia longipalpis (Lutz & Neiva, 1912) by Leishmania infantum in a municipality with a high incidence of visceral leishmaniasis in the Brazilian Midwest

ABSTRACT Background: Here, Leishmania presence in sand flies from Três Lagoas, Mato Grosso do Sul, Brazil, after visceral leishmaniasis (VL) was investigated. Methods: In April 2022, two light traps were deployed within and around the residence for two days post-VL case report. Results: A total of 120 Lutzomyia longipalpis were collected. Suprapyloric flagellates were found in a female sand fly with eggs and residual blood during midgut dissection. Sequencing of ITS1 and cytb fragments confirmed Leishmania infantum DNA and identified Homo sapiens as the blood source, respectively. Conclusions: This study emphasizes the importance of monitoring sand flies in VL endemic areas.

Natural infection of Lutzomyia longipalpis (Cembrene-1 population) with Leishmania infantum in a new visceral leishmaniasis focus in the eastern region of São Paulo State, Brazil

Abstract INTRODUCTION Visceral leishmaniasis (VL) transmission has been associated with two different populations of the Lutzomyia longipalpis complex in São Paulo state. METHODS In a recent focus of VL, we captured and dissected sand flies and investigated Leishmania infantum infection by parasitological, PCR, and sequencing analysis. RESULTS Flagellates were observed in 2 of 47 (4.2%) cembrene-1 Lu. longipalpis females. The sequences obtained matched those of Le. infantum. CONCLUSIONS We found that the transmission of Le. infantum by cembrene-1 females may occur at a high rate in this focus of VL and presented new data on the vector capacity of this population.

Visceral Leishmaniasis in Bolivia: Current Status

Abstract INTRODUCTION In Bolivia, before 1982 there were no records of visceral leishmaniasis (VL) cases that would allow us to review and describe the temporospatial occurrence of VL by ecoregions in provinces and departments of Bolivia to evaluate its impact on public health, risk of outbreaks, or dispersion. METHODS This update on VL in Bolivia is based on research, reviews, and retrospective literature analyses of online data and libraries and institutional reports, from 1939 to the present. RESULTS In Bolivia, 56 cases of VL have been reported. Until 2014, only three endemic departments had been identified (La Paz, Santa Cruz, and Tarija). Since then, further cases have been recorded in Pando, Cochabamba, and Beni, and in Chuquisaca in 2015. In Yungas, a VL focus was confirmed by isolating and comparing parasites from human and dog cases, and from the Lu. longipalpis vector. VL cases from seven departments, involving 12 different ecoregions were located within the Amazon and Plata basins. CONCLUSIONS We confirmed that dogs are its primary reservoir, and Lutzomyia longipalpis is its main vector (currently dispersed in six departments). The primary vectors in areas where Lutzomyia longipalpis is absent are Migonemyia migonei and Lutzomyia cruzi.

Ecology of phlebotomine sand flies in a Brazilian area with recent leishmaniasis transmission (Itaúna, in Minas Gerais state)

Abstract INTRODUCTION: Leishmaniasis constitutes a serious but neglected tropical disease. Recently, socio-environmental, biological and physical changes have altered the range of leishmaniasis, causing it to spread into urban areas. In Minas Gerais, the disease is endemic, exhibiting regional differences and reaching urban centers. The purpose of this study was to evaluate entomological aspects related to the ecoepidemiology of leishmaniasis in Itaúna. METHODS: Monthly catches with HP traps were carried out from June 2017 to May 2018, in three ecological areas (urban, rural, and forest). The adaptability of the species to anthropic environments was assessed using the synanthropy index (SI). RESULTS: We collected 1306 specimens of phlebotomine sand flies. Of the species of medical importance, Lutzomyia longipalpis, the vector of Leishmania infantum, represented 90.4% of the specimens identified at species level (n=1260). Nyssomyia whitmani, the vector of Leishmania braziliensis, represented 1.6% of the total. Lu. longipalpis displayed an SI of +95.8, a value that denotes a marked preference for human environments. For Ny. whitmani, the SI was -25, expressing the tendency of this species to occupy uninhabited areas. The population of the three most numerous species captured increased with rain, high temperatures, and high relative humidity. Although captured at low numbers, Ny. whitmani showed a different profile concerning the climate variables analyzed. CONCLUSIONS: Understanding the epidemiology of the disease may assist the health services in formulating effective control measures for improving community health and contributing to the establishment of a dynamic relationship and a global awareness of the health/disease process.

Sandflies in an endemic area for Visceral Leishmaniasis in Northeastern Brazil / Flebotomíneos em uma área endêmica para Leishmaniose Visceral no Nordeste do Brasil

Abstract Phlebotomines of the genus Lutzomyia are important vector for species of Leishmania, the etiological agent of leishmaniasis. The aim of this study was to assess the diversity of sandflies in an endemic area for Visceral Leishmaniasis (VL). Sampling was performed in four localities on the coast of the municipality of Goiana, state of Pernambuco, Northeastern Brazil. Specimens were collected monthly on three consecutive nights, from November 2017 to October 2018. CDC light traps were installed at a height of 1.5 m above the ground, in two ecotypes (i.e. tree and animal facility), both in peridomestic areas. A total of 5,205 sandflies were collected, among which the species Lutzomyia longipalpis (99.85%; 5,197/5,205) was the most common, followed by Lutzomyia evandroi (0.13%; 07/5,205) and Lutzomyia whitmani (0.02%; 01/5,205). Specimens of L. longipalpis were collected throughout the study period and most of them were found near to the animal facilities. The findings from this research indicate that vectors for Leishmania infantum are present in the study area throughout the year, along with occurrences of vectors relating to Cutaneous Leishmaniasis (CL). Preventive vector control measures need to be implemented in Goiana to reduce the risk of infection for the human and animal populations.

Resumo Flebotomíneos do gênero Lutzomyia são importantes vetores de espécies de Leishmania, agente etiológico das leishmanioses. O objetivo deste estudo foi avaliar a diversidade de flebotomíneos em área endêmica para Leishmaniose Visceral (LV). As coletas foram realizadas em quatro localidades do litoral do município de Goiana, Pernambuco, Nordeste do Brasil. Os espécimes foram coletados mensalmente em três noites consecutivas de novembro de 2017 a outubro de 2018. Foram instaladas armadilhas luminosas modelo CDC a uma altura de 1,5 m acima do solo em dois ecótopos (ex. árvore e instalações de animais), ambos em áreas peridomiciliares. Um total de 5.205 flebotomíneos foi coletado, sendo Lutzomyia longipalpis (99,85%; 5.197/5.205) a mais comum, seguida por Lutzomyia evandroi (0,13%; 07/5.205) e Lutzomyia whitmani (0,02%; 01/5.205). L. longipalpis foi coletada durante todo o período do estudo. A maioria dos espécimes foi detectada perto das instalações dos animais. Os achados deste estudo indicam a presença de vetores de Leishmania infantum na área avaliada ao longo do ano, bem como a ocorrência de vetores relacionados à Leishmaniose Cutânea (LC). Medidas preventivas de controle vetorial devem ser implementadas em Goiana para reduzir o risco de infecção à população humana e animal.

Development of Leishmania mexicana in Lutzomyia longipalpis in the absence of sugar feeding

The leishmaniases are caused by Leishmania parasites and transmitted through the bites of phlebotomine sand flies. During parasite development inside the vector's midgut, promastigotes move towards the stomodeal valve, a mechanism that is crucial for transmission. It has been reported that the sugar meal acquired by sand flies during feeding between bloodmeals is essential for the development and migration of parasites. We demonstrated that the distribution of Leishmania mexicana parasites was affected by the sugar meals obtained by the sand flies. Promastigote migration towards the cardia region seems to be only partially based on the stimuli provided by sugar molecules. In the absence of sugars, significant amounts of parasites developed in the hindgut. In addition, sugar meals were important for the survival of sand flies, especially during blood digestion, presumably supporting their energy requirements.

Chicken eggs as a surveillance tool for malaria and leishmaniasis vector presence

Abstract INTRODUCTION: Malaria and leishmaniases are transmitted by vectors during blood-feeding. Vector-infected animals develop antibodies against the vector's saliva. This study evaluated IgY antibody detection in the chicken eggs exposed to bites from Migonemyia migonei, Lutzomyia longipalpis and Anopheles aquasalis. METHODS: We used ELISA to quantify the antibody levels in the sera and exposed chicken eggs. RESULTS: High IgY levels were observed following immunization; furthermore, higher reactivity was observed in the eggs and species-specific immune response was observed post final immunization. CONCLUSIONS: Chicken eggs can be used as sentinels to surveil vector saliva antibodies.

Alternative splicing originates different domain structure organization of Lutzomyia longipalpis chitinases

BACKGROUND The insect chitinase gene family is composed by more than 10 paralogs, which can codify proteins with different domain structures. In Lutzomyia longipalpis, the main vector of visceral leishmaniasis in Brazil, a chitinase cDNA from adult female insects was previously characterized. The predicted protein contains one catalytic domain and one chitin-binding domain (CBD). The expression of this gene coincided with the end of blood digestion indicating a putative role in peritrophic matrix degradation. OBJECTIVES To determine the occurrence of alternative splicing in chitinases of L. longipalpis. METHODS We sequenced the LlChit1 gene from a genomic clone and the three spliced forms obtained by reverse transcription polymerase chain reaction (RT-PCR) using larvae cDNA. FINDINGS We showed that LlChit1 from L. longipalpis immature forms undergoes alternative splicing. The spliced form corresponding to the adult cDNA was named LlChit1A and the two larvae specific transcripts were named LlChit1B and LlChit1C. The B and C forms possess stop codons interrupting the translation of the CBD. The A form is present in adult females post blood meal, L4 larvae and pre-pupae, while the other two forms are present only in L4 larvae and disappear just before pupation. Two bands of the expected size were identified by Western blot only in L4 larvae. MAIN CONCLUSIONS We show for the first time alternative splicing generating chitinases with different domain structures increasing our understanding on the finely regulated digestion physiology and shedding light on a potential target for controlling L. longipalpis larval development.

Reflexões sobre cenários, vigilância epidemiológica e controle da transmissão de leishmaniose visceral no estado de São Paulo / Analysis of epidemiological scenarios and the relationship with surveillance and control of visceral leishmaniasis transmission in the state of São Paulo

Diferenças regionais nos padrões de transmissão da leishmaniose visceral tem se constituído ao longo do tempo em diferentes cenários para enfrentamento da doença no estado de São Paulo. Entre 1999 a 2016, Lutzomyia longipalpis foi detectado em 95,8% (137/143) dos municípios com transmissão humana, canina ou ambas. Todavia, a ocorrência de casos humanos em município do litoral e aumento de casos caninos na região metropolitana de São Paulo sem detecção do vetor, sugere novos desafios à vigilância e ao controle da doença. No oeste do estado, prevalece à forma clássica de transmissão com 19,70% (13/66) dos municípios prioritários, acumulando 63,8% (245/384) dos casos no triênio 2015-2016-2017. Esse padrão epidemiológico é compatível com a regra empírica 80/20. Alguns destes municípios houve remissão da transmissão, porem com posterior aumento no decorrer dos anos. Desse modo conclui-se que a vigilância e o controle da leishmaniose visceral terá como desafio a busca por novas ferramentas para o enfrentamento da transmissão nos diversos cenários e para o efetivo controle da doença.

Regional characteristics influence the patterns of transmission of visceral leishmaniasis revealing over time different scenarios for the control of the disease in the state of São Paulo. Between 1999 and 2016, Lutzomyia longipalpis was detected in 95.8% (137/143) of the municipalities with human, canine or both transmissions. However, the occurrence of human cases in a new municipality and an increase in canine cases in the metropolitan region of São Paulo without detection of the vector suggest new challenges to surveillance and control of the disease. In the western part of the state, the classic form of transmission prevails with 19.70% (13/66) of the priority municipalities, accumulating 63.8% (245/384) of cases in the triennium 2015-2016-2017. This epidemiological pattern is compatible with the 80/20 empirical rule. Some of these municipalities had remission of the transmission with a subsequent increase in the number of cases over the years. Thus, it is concluded that the surveillance and control system of visceral leishmaniasis should seek new tools for coping with transmission in the various scenarios and for effective control of the disease.

Addressing the recent dispersion of urban visceral leishmaniasis in the border of Argentina, Brazil, Paraguay + Uruguay + Bolivia ­ Project IDRC

The territory located in the border of Argentina, Brazil and Paraguay is endemic for tegumentary leishmaniasis (TL). However, Lutzomyia longipalpis first report in the area was in 2010-Argentina, in 2012-Brazil, and no records in the Paraguayan border despite of reports of human visceral leishmaniasis (VL) cases. Therefore, we developed a research from 2014 to 2017 to study VL in the three-country border at locality level; Uruguay-2015, and Bolivia-2016 joined latter due to the alerts of VL in the Argentinean borders. The space-time distributions of vectors, infected dogs and environmental variables were recorded and associated at three progressive scales, while anthropological surveys were performed. Three scenarios were characterized based on canine VL prevalence, vector presence-abundance and the spatial distribution consistency between them: settled VL, incipient VL, and steady TL with imported canine VL. The vector abundance was clustered in 'hot spots' persistent in time that could act as 'source populations'. The clustering distribution was associated with environmental variables at the different scales studied. Therefore, the vector distribution (proxy of human-dog exposure) could be modeled in recent southern scenarios to focus the surveillance and interventions on predicted 'hot spots', in order to increase the effectiveness and efficiency of program activities. (AU)

O território localizado na fronteira da Argentina, Brasil e Paraguai é endêmico para leishmaniose tegumentar (LT). Entretanto, o primeiro relato de Lutzomyia longipalpis na área foi em 2010-Argentina, em 2012-Brasil, sem registros na fronteira em Paraguai apesar dos casos de leishmaniose visceral humana (LV). Portanto, desenvolvemos uma pesquisa de 2014 a 2017 para estudar a LV na tríplice fronteira em nível de localidades; Uruguai-2015 e Bolívia-2016 aderiram mais tarde devido aos alertas de LV nas fronteiras argentinas. As distribuições espaço-temporais de vetores, cães infectados e as variáveis ambientais foram registradas e associadas em três escalas progressivas, enquanto se realizou o inquérito antropológico. Três cenários foram caracterizados com base na prevalência de LV canina, na abundância-presença de vetores, e a coerência da distribuição espacial entre eles: LV instalada, LV incipiente e LT estável com LV canina importada. A abundância de vetores foi agrupada em "pontos quentes" persistentes no tempo que poderiam atuar como "populações fonte". A distribuição de agrupamento foi associada a variáveis ambientais nas diferentes escalas. Portanto, a distribuição vetorial (proxy da exposição humana a cães) poderia ser modelada em cenários recentes do sul para focar a vigilância e as intervenções nos "pontos quentes" previstos, a fim de aumentar a eficácia e a eficiência das atividades do programa. (AU)

Vetor ou vetores? Capacidade vetorial e estratégias de controle / Vector or vectors? Vectorial capacity and control strategies

Variáveis relacionadas a fatores epidemiológicos, ao ambiente, ao agente etiológico, ao vetor e aos reservatórios parecem atuar na determinação dos diferentes cenários de transmissão da leishmaniose visceral no Brasil. No estado de São Paulo a leishmaniose visceral (LV) não apresenta um padrão epidemiológico homogêneo por todas suas regiões, parecendo refletir uma multitude de cenários propícios para a ocorrência da transmissão dentro do território Paulista. Lutzomyia longipalpis é composta por um complexo de espécies das quais duas são encontradas no Estado de São Paulo e parecem possuir diferença na capacidade vetorial. É provável que essa diferença seja o fator determinante na caracterização dos diferentes padrões epidemiológicos observados nas diferentes regiões do Estado. No presente estudo, procuramos determinar a distribuição temporal e geográfica das espécies do complexo Lu. longipalpis, dos casos caninos e dos casos humanos de LV como elementos chave para ajudar na caracterização de alguns cenários de transmissão da doença e apontar áreas de maior risco para a aquisição da doença. Por outro lado, a recente e inesperada ocorrência de transmissão da LV em localidades sem a presença da Lu. longipalpis, caracteriza mais um novo cenário, onde a transmissão da Leishmania infantum ao homem se mostrou possível, configurando um novo desafio para as autoridades da saúde pública. (AU)

Variables related to epidemiological factors, etiologic agent, environment, vector and reservoirs seem to act in determining the different scenarios of transmission of visceral leishmaniasis (VL) in Brazil. In the state of São Paulo, VL does not present a homogeneous epidemiological pattern across all its regions, seeming to reflect a multitude of scenarios conducive to the occurrence of transmission within Paulista territory. Lutzomyia longipalpis is composed of a complex of species of which two are found in the state of São Paulo and appear to have a difference in vector capacity. It is likely that this difference is the determining factor in the characterization of the different epidemiological patterns observed in the different regions of the State. In the present study, we sought to determine the temporal and geographic distribution of Lu. longipalpis species, canine cases and human cases of VL as key elements to help characterize some scenarios of transmission of the disease and to indicate areas of greater risk for disease acquisition. The recent and unexpected occurrence of VL transmission in localities without the presence of Lu. longipalpis characterizes another new scenario, where other species of san flies can transmit Leishmania infantum to man and configuring a new challenge for public health authorities. (AU)

Reflexões sobre cenários, vigilância epidemiológica e controle da transmissão de leishmaniose visceral no estado de São Paulo / Analysis of epidemiological scenarios and the relationship with surveillance and control of visceral leishmaniasis transmission in the state of São Paulo

Diferenças regionais nos padrões de transmissão da leishmaniose visceral tem se constituído ao longo do tempo em diferentes cenários para enfrentamento da doença no estado de São Paulo. Entre 1999 a 2016, Lutzomyia longipalpis foi detectado em 95,8% (137/143) dos municípios com transmissão humana, canina ou ambas. Todavia, a ocorrência de casos humanos em município do litoral e aumento de casos caninos na região metropolitana de São Paulo sem detecção do vetor, sugere novos desafios à vigilância e ao controle da doença. No oeste do estado, prevalece à forma clássica de transmissão com 19,70% (13/66) dos municípios prioritários, acumulando 63,8% (245/384) dos casos no triênio 2015-2016-2017. Esse padrão epidemiológico é compatível com a regra empírica 80/20. Alguns destes municípios houve remissão da transmissão, porem com posterior aumento no decorrer dos anos. Desse modo conclui-se que a vigilância e o controle da leishmaniose visceral terá como desafio a busca por novas ferramentas para o enfrentamento da transmissão nos diversos cenários e para o efetivo controle da doença.

Regional characteristics influence the patterns of transmission of visceral leishmaniasis revealing over time different scenarios for the control of the disease in the state of São Paulo. Between 1999 and 2016, Lutzomyia longipalpis was detected in 95.8% (137/143) of the municipalities with human, canine or both transmissions. However, the occurrence of human cases in a new municipality and an increase in canine cases in the metropolitan region of São Paulo without detection of the vector suggest new challenges to surveillance and control of the disease. In the western part of the state, the classic form of transmission prevails with 19.70% (13/66) of the priority municipalities, accumulating 63.8% (245/384) of cases in the triennium 2015-2016-2017. This epidemiological pattern is compatible with the 80/20 empirical rule. Some of these municipalities had remission of the transmission with a subsequent increase in the number of cases over the years. Thus, it is concluded that the surveillance and control system of visceral leishmaniasis should seek new tools for coping with transmission in the various scenarios and for effective control of the disease.

Addressing the recent dispersion of urban visceral leishmaniasis in the border of Argentina, Brazil, Paraguay + Uruguay + Bolivia – Project IDRC / Abordando a recente dispersão da leishmaniose visceral urbana nas fronteiras da Argentina, Brasil e Paraguai + Uruguai + Bolívia - Projeto IDRC

The territory located in the border of Argentina, Brazil and Paraguay is endemic for tegumentary leishmaniasis (TL). However, Lutzomyia longipalpis first report in the area was in 2010-Argentina, in 2012-Brazil, and no records in the Paraguayan border despite of reports of human visceral leishmaniasis (VL) cases. Therefore, we developed a research from 2014 to 2017 to study VL in the three-country border at locality level; Uruguay-2015, and Bolivia-2016 joined latter due to the alerts of VL in the Argentinean borders. The space-time distributions of vectors, infected dogs and environmental variables were recorded and associated at three progressive scales, while anthropological surveys were performed. Three scenarios were characterized based on canine VL prevalence, vector presence-abundance and the spatial distribution consistency between them: settled VL, incipient VL, and steady TL with imported canine VL. The vector abundance was clustered in ‘hot spots’ persistent in time that could act as ‘source populations’. The clustering distribution was associated with environmental variables at the different scales studied. Therefore, the vector distribution (proxy of human-dog exposure) could be modeled in recent southern scenarios to focus the surveillance and interventions on predicted ‘hot spots’, in order to increase the effectiveness and efficiency of program activities.

O território localizado na fronteira da Argentina, Brasil e Paraguai é endêmico para leishmaniose tegumentar (LT). Entretanto, o primeiro relato de Lutzomyia longipalpis na área foi em 2010-Argentina, em 2012-Brasil, sem registros na fronteira em Paraguai apesar dos casos de leishmaniose visceral humana (LV). Portanto, desenvolvemos uma pesquisa de 2014 a 2017 para estudar a LV na tríplice fronteira em nível de localidades; Uruguai-2015 e Bolívia-2016 aderiram mais tarde devido aos alertas de LV nas fronteiras argentinas. As distribuições espaço-temporais de vetores, cães infectados e as variáveis ambientais foram registradas e associadas em três escalas progressivas, enquanto se realizou o inquérito antropológico. Três cenários foram caracterizados com base na prevalência de LV canina, na abundância-presença de vetores, e a coerência da distribuição espacial entre eles: LV instalada, LV incipiente e LT estável com LV canina importada. A abundância de vetores foi agrupada em “pontos quentes” persistentes no tempo que poderiam atuar como “populações fonte”. A distribuição de agrupamento foi associada a variáveis ambientais nas diferentes escalas. Portanto, a distribuição vetorial (proxy da exposição humana a cães) poderia ser modelada em cenários recentes do sul para focar a vigilância e as intervenções nos “pontos quentes” previstos, a fim de aumentar a eficácia e a eficiência das atividades do programa.

Vetor ou vetores? Capacidade vetorial e estratégias de controle / Vector or vectors? Vectorial capacity and control strategies

Variáveis relacionadas a fatores epidemiológicos, ao ambiente, ao agente etiológico, ao vetor e aos reservatórios parecem atuar na determinação dos diferentes cenários de transmissão da leishmaniose visceral no Brasil. No estado de São Paulo a leishmaniose visceral (LV) não apresenta um padrão epidemiológico homogêneo por todas suas regiões, parecendo refletir uma multitude de cenários propícios para a ocorrência da transmissão dentro do território Paulista. Lutzomyia longipalpis é composta por um complexo de espécies das quais duas são encontradas no Estado de São Paulo e parecem possuir diferença na capacidade vetorial. É provável que essa diferença seja o fator determinante na caracterização dos diferentes padrões epidemiológicos observados nas diferentes regiões do Estado. No presente estudo, procuramos determinar a distribuição temporal e geográfica das espécies do complexo Lu. longipalpis, dos casos caninos e dos casos humanos de LV como elementos chave para ajudar na caracterização de alguns cenários de transmissão da doença e apontar áreas de maior risco para a aquisição da doença. Por outro lado, a recente e inesperada ocorrência de transmissão da LV em localidades sem a presença da Lu. longipalpis, caracteriza mais um novo cenário, onde a transmissão da Leishmania infantum ao homem se mostrou possível, configurando um novo desafio para as autoridades da saúde pública.

Variables related to epidemiological factors, etiologic agent, environment, vector and reservoirs seem to act in determining the different scenarios of transmission of visceral leishmaniasis (VL) in Brazil. In the state of São Paulo, VL does not present a homogeneous epidemiological pattern across all its regions, seeming to reflect a multitude of scenarios conducive to the occurrence of transmission within Paulista territory. Lutzomyia longipalpis is composed of a complex of species of which two are found in the state of São Paulo and appear to have a difference in vector capacity. It is likely that this difference is the determining factor in the characterization of the different epidemiological patterns observed in the different regions of the State. In the present study, we sought to determine the temporal and geographic distribution of Lu. longipalpis species, canine cases and human cases of VL as key elements to help characterize some scenarios of transmission of the disease and to indicate areas of greater risk for disease acquisition. The recent and unexpected occurrence of VL transmission in localities without the presence of Lu. longipalpis characterizes another new scenario, where other species of san flies can transmit Leishmania infantum to man and configuring a new challenge for public health authorities.

Lower galactosylation levels of the Lipophosphoglycan from Leishmania (Leishmania) major-like strains affect interaction with Phlebotomus papatasi and Lutzomyia longipalpis

BACKGROUND Leishmania major is an Old World species causing cutaneous leishmaniasis and is transmitted by Phlebotomus papatasi and Phlebotomus duboscqi. In Brazil, two isolates from patients who never left the country were characterised as L. major-like (BH49 and BH121). Using molecular techniques, these isolates were indistinguishable from the L. major reference strain (FV1). OBJECTIVES We evaluated the lipophosphoglycans (LPGs) of the strains and their behaviour in Old and New World sand fly vectors. METHODS LPGs were purified, and repeat units were qualitatively evaluated by immunoblotting. Experimental in vivo infection with L. major-like strains was performed in Lutzomyia longipalpis (New World, permissive vector) and Ph. papatasi (Old World, restrictive or specific vector). FINDINGS The LPGs of both strains were devoid of arabinosylated side chains, whereas the LPG of strain BH49 was more galactosylated than that of strain BH121. All strains with different levels of galactosylation in their LPGs were able to infect both vectors, exhibiting colonisation of the stomodeal valve and metacyclogenesis. The BH121 strain (less galactosylated) exhibited lower infection intensity compared to BH49 and FV1 in both vectors. MAIN CONCLUSIONS Intraspecific variation in the LPG of L. major-like strains occur, and the different galactosylation levels affected interactions with the invertebrate host.

Effectiveness of dog collars impregnated with 4% deltamethrin in controlling visceral leishmaniasis in Lutzomyia longipalpis (Diptera: Psychodidade: Phlebotominae) populations

BACKGROUND There is little information on the effect of using deltamethrin-impregnated dog collars for the control of canine visceral leishmaniasis. OBJECTIVES The objective of this study was to evaluate the effectiveness of the use of 4% deltamethrin-impregnated collars (Scalibor®) in controlling visceral leishmaniasis in Lutzomyia longipalpis by comparing populations in intervention and non-intervention areas. METHODS Phlebotomine flies were captured over 30 months in four neighbourhoods with intense visceral leishmaniasis transmission in Fortaleza and Montes Claros. We calculated the rates of domicile infestation, relative abundance of Lu. longipalpis, and Lu. longipalpis distribution in each site, capture location (intra- and peridomestic locations) and area (intervention and non-intervention areas). FINDINGS In the control area in Fortaleza, the relative abundance of Lu. longipalpis was 415 specimens at each capture site, whereas in the intervention area it was 159.25; in Montes Claros, the relative abundance was 5,660 specimens per capture site in the control area, whereas in the intervention area it was 2,499.4. The use of dog collars was associated with a reduction in captured insects of 15% (p = 0.004) and 60% (p < 0.001) in Montes Claros and Fortaleza, respectively. MAIN CONCLUSIONS We observed a lower vector abundance in the intervention areas, suggesting an effect of the insecticide-impregnated collars.

The role of gallery forests in maintaining Phlebotominae populations: potential Leishmania spp. vectors in the Brazilian savanna

BACKGROUND Knowledge on synanthropic phlebotomines and their natural infection by Leishmania is necessary for the identification of potential areas for leishmaniasis occurrence. OBJECTIVE To analyse the occurrence of Phlebotominae in gallery forests and household units (HUs) in the city of Palmas and to determine the rate of natural infection by trypanosomatids. METHODS Gallery forests and adjacent household areas were sampled on July (dry season) and November (rainy season) in 2014. The total sampling effort was 960 HP light traps and eight Shannon traps. Trypanosomatids were detected in Phlebotominae females through the amplification of the SSU rDNA region, and the positive samples were used in ITS1-PCR. Trypanosomatid species were identified using sequencing. FINDINGS A total of 1,527 sand flies representing 30 species were captured in which 949 (28 spp.) and 578 (22 spp.) were registered in July and November, respectively. In July, more specimens were captured in the gallery forests than in the HUs, and Nyssomyia whitmani was particularly frequent. In November, most of the specimens were found in the HUs, and again, Ny. whitmani was the predominant species. Lutzomyia longipalpis was commonly found in domestic areas, while Bichromomyia flaviscutellata was most frequent in gallery forests. Molecular analysis of 154 pools of females (752 specimens) identified Leishmania amazonensis, L. infantum, and Crithidia fasciculata in Ny. whitmani, as well as L. amazonensis in Lu. longipalpis, Trypanosoma sp. and L. amazonensis in Pintomyia christenseni, and L. amazonensis in both Psathyromyia hermanlenti and Evandromyia walkeri. MAIN CONCLUSIONS These results show the importance of gallery forests in maintaining Phlebotominae populations in the dry month, as well as their frequent occurrence in household units in the rainy month. This is the first study to identify Leishmania, Trypanosoma, and Crithidia species in Phlebotominae collected in Palmas, Tocantins, Brazil.

Environmental suitability for Lutzomyia longipalpis in a subtropical city with a recently established visceral leishmaniasis transmission cycle, Argentina

BACKGROUND Visceral leishmaniasis (VL) is an endemic disease in northeastern Argentina including the Corrientes province, where the presence of the vector and canine cases of VL were recently confirmed in December 2008. OBJECTIVES The objective of this study was to assess the modelling of micro- and macro-habitat variables to evaluate the urban environmental suitability for the spatial distribution of Lutzomyia longipalpis presence and abundance in an urban scenario. METHODS Sampling of 45 sites distributed throughout Corrientes city (Argentina) was carried out using REDILA-BL minilight traps in December 2013. The sampled specimens were identified according to methods described by Galati (2003). The analysis of variables derived from the processing of satellite images (macro-habitat variables) and from the entomological sampling and surveys (micro-habitat variables) was performed using the statistical software R. Three generalised linear models were constructed composed of micro- and macro-habitat variables to explain the spatial distribution of the abundance of Lu. longipalpis and one composed of micro-habitat variables to explain the occurrence of the vector. FINDINGS A total of 609 phlebotominae belonging to five species were collected, of which 56% were Lu. longipalpis. In addition, the presence of Nyssomyia neivai and Migonemya migonei, which are vectors of tegumentary leishmaniasis, were also documented and represented 34.81% and 6.74% of the collections, respectively. The explanatory variable normalised difference vegetation index (NDVI) described the abundance distribution, whereas the presence of farmyard animals was important for explaining both the abundance and the occurrence of the vector. MAIN CONCLUSIONS The results contribute to the identification of variables that can be used to establish priority areas for entomological surveillance and provide an efficient transfer tool for the control and prevention of vector-borne diseases.

Serological tests fail to discriminate dogs with visceral leishmaniasis that transmit Leishmania infantum to the vector Lutzomyia longipalpis

Abstract INTRODUCTION The control of reservoirs for Leishmania infantum -induced zoonotic visceral leishmaniasis requires the identification of dogs posing a population risk. Here, we assessed the performance of several assays to identify Lutzomyia longipalpis infectious dogs. METHODS We evaluated 99 dogs that were positive for visceral leishmaniasis based on parasite identification. Serological analyses were performed using an enzyme-linked immunosorbent assay, immunofluorescence antibody tests in 1:40 and 1:80 dilutions, rapid dual path platform tests, immunochromatographic assay with a recombinant rK39 antigen, fast agglutination screening tests, and direct agglutination tests. We also performed PCR to analyze peripheral blood and xenodiagnosis. RESULTS Forty-six dogs infected at least one L. longipalpis specimen. Although the serological test sensitivities were above 85% for detecting L. longipalpis infectious dogs, none showed a satisfactory performance, as both specificity (0.06 to 13%) and the area under the receiver operating characteristic curve (45 to 53%) were low. The PCR results were also weak, with a sensitivity of 30%, specificity of 72%, and an area under the receiver operating characteristic curve of 51%. The infected L. longipalpis proportion was higher among asymptomatic dogs than symptomatic dogs. Among the symptomatic dogs, those with ulceration-free skin diseases were more infectious, with an odds ratio of 9.3 (confidence interval of 1.10 - 428.5). The larger the number of insects fed, the greater the detected infectiousness. CONCLUSIONS Our study supports the imperative to develop novel technologies for identifying the infectious dogs that transmit L. infantum for the benefit of public health.

Avaliação da infectividade parasitária a Lutzomyia longipalpis por xenodiagnóstico em cães tratados para leishmaniose visceral naturalmente adquirida / Evaluation of parasite infectivity for Lutzomyia longipalpis by xenodiagnosis in dogs treated for natural visceral leishmaniasis

O efeito de um protocolo quimioterápico multidrogas contra a leishmaniose visceral (LV) canina, sobre a capacidade de transmissão de Leishmania infantum ao vetor, foi analisado por meio de xenodiagnóstico. Trinta e cinco cães naturalmente infectados foram avaliados antes e durante o tratamento com a combinação de metronidazol, cetoconazol e alopurinol a cada três meses por até um ano. Em cada avaliação, os cães foram individualmente submetidos ao xenodiagnóstico e quantificação da carga parasitária por PCR quantitativa. O tratamento foi eficaz em bloquear a transmissibilidade parasitária do cão para o flebotomíneo (p= 0,011) nos cães avaliados. Houve significante correlação entre recuperação clínica e infectividade: cães com melhora clínica mais evidente apresentaram menores chances de transferir L. infantum ao Lutzomyia longipalpis via xenodiagnóstico (r=0,528, p= 0,002). Esses resultados demonstram que o tratamento canino com o protocolo proposto pode representar uma alternativa ao sacrifício de cães no Brasil como medida de controle da doença, uma vez que as drogas utilizadas não são aplicadas ao tratamento da LV humana em áreas endêmicas.(AU)

The outcome of a multidrug chemotherapeutic protocol against canine visceral leishmaniasis (VL) has been evaluated for its effect on dogs' capacity of transferring Leishmania infantum to sand flies by xenodiagnosis. Thirty-five naturally infected dogs were examined before and during treatment with a combination of metronidazole, ketoconazole, and allopurinol, at every three months up to one year. For each evaluation, treated dogs were individually submitted to xenodiagnosis and quantitative PCR to quantify parasite load in sand flies. The treatment was effective in blocking parasite transmission from host to sand flies (p=0.011) in the assessed dogs. There was a significant correlation between clinical improvement and sand fly infectivity: dogs that achieved better clinical conditions showed a lower chance of L. infantum transference to vector by xenodiagnosis (r=0.528, p=0.002). These results demonstrate that the treatment of dogs with the proposed protocol may represent an alternative to dog culling in Brazil for disease control, since these drugs are not used for treating human VL in endemic areas.(AU)