Diversity and relative abundance of immature mosquitoes (Diptera: Culicidae) in Hohenbergia catingae Ule bromeliads and larvitraps in the Nísia Floresta National Forest, northeast Brazil.

The Nísia Floresta National Forest, located in Rio Grande do Norte (RN), is an important remnant of the Atlantic Forest biome in Brazil. Bromeliad tanks in this forest offer suitable breeding sites for mosquito species that may act as viral vectors, thus posing an epidemiological concern. However, studies investigating the presence of immature Culicidae in natural breeding sites in RN have thus far been restricted to Caatinga vegetation. This study investigated mosquitoes and their natural breeding sites in bromeliads growing in the Nísia Floresta National Forest. From March 2013 to February 2014, monthly samples were collected from the tanks of five randomly selected bromeliads and larvitraps placed in each of the three forest management areas. Hohenbergia catingae Ule (Hohenbergia bromeliad) is an important shelter for immature mosquitoes. Culex (Microculex) was the predominant species, representing 86% of the immature mosquitoes collected. A rare occurrence of Aedes (Stegomyia) aegypti (Linnaeus, 1762) (generally associated with urban areas under high anthropogenic influence) was observed, highlighting the importance of investigating the presence of mosquitoes in different natural habitats. An analysis of species diversity revealed that species such as Culex imitator Theobald, 1903 and Culex davisi Kumm, 1933, have a strong association with bromeliads. In tire traps (larvitraps) Aedes (Stegomyia) albopictus Skuse, 1894 was predominant. Environmental changes, such as deforestation, removal of bromeliads, and climate change in the area, can influence the migration of species and adaptation to new habitats in a peridomiciliary environment around the forest, consequently the possibility of transmission of virus and other pathogens.

Tephrosia toxicaria (Sw.) Pers. extracts: Screening by examining aedicidal action under laboratory and field conditions along with its antioxidant, antileishmanial, and antimicrobial activities.

An increase in the incidence of arboviral, microbial and parasitic infections, and to disorders related to oxidative stress has encouraged the development of adjuvant therapies based on natural formulations, such as those involving plant extracts. Thus, to expand the repertoire of the available therapeutic options, this study aimed to describe the versatility of Tephrosia toxicaria (Sw.) (Pers., 1807) extracts for the control of arbovirus vectors, as well as their antioxidant, antileishmanial, and antimicrobial potential. Among the aqueous and hydroethanolic extracts obtained, the hydroethanolic extract from roots (RHA) was identified as the most active larvicide extract demonstrating, respectively, the lowest lethal concentration (mg/mL) for 50%, 90% and 99% of Aedes aegypti (L., 1762) and Aedes albopictus (S., 1894) larvae, observed at 24 h (0.33, 0.84 and 1.80; 0.32, 0.70 and 1.32) and 48 h (0.17, 0.51 and 1.22; 0.26, 0.47 and 0.78) post-exposure. Field assays revealed that RHA (0.84 mg/mL) is a potential oviposition deterrent, reducing egg-laying by approximately 90%. RHA (0.1 mg/mL) also exhibited antioxidant activity for the following tests: total antioxidant capacity (286.86 mg AAE/g), iron (87.16%) and copper (25.64%) chelation, and superoxide scavenging (10%). In the cell culture assays, RHA (0.1 mg/mL) promoted regeneration of metabolic activity (92% cell viability) in cells exposed to oxidative stress. Furthermore, RHA displayed weak antileishmanial activity (IC50 = 3.53 mg/mL) against Leishmania amazonensis and not exhibit antimicrobial activity. The extraction favored the concentration of carbohydrates in RHA, in addition to lectins and protease inhibitors, with molecular masses estimated between 10 and 24 kDa. Cytotoxicity and phytotoxicity analyses of RHA suggested its biosecurity. Thus, RHA is a multivalent extract with insecticide and antioxidant properties at low and safe concentrations. However, others studies on its indirect toxic effects are ongoing to ensure the complete safety of RHA.

Potential vectors of Leishmania spp. in an Atlantic Forest conservation unit in northeastern Brazil under anthropic pressure.

BACKGROUND: Phlebotomines are a group of insects which include vectors of the Leishmania parasites that cause visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL), diseases primarily affecting populations of low socioeconomic status. VL in Brazil is caused by Leishmania infantum, with transmission mainly attributed to Lutzomyia longipalpis, a species complex of sand fly, and is concentrated mainly in the northeastern part of the country. CL is distributed worldwide and occurs in five regions of Brazil, at a higher incidence in the north and northeast regions, with etiological agents, vectors, reservoirs and epidemiological patterns that differ from VL. The aim of this study was to determine the composition, distribution and ecological relationships of phlebotomine species in an Atlantic Forest conservation unit and nearby residential area in northeastern Brazil. METHODS: Centers for Disease Control and Shannon traps were used for collections, the former at six points inside the forest and in the peridomestic environment of surrounding residences, three times per month for 36 months, and the latter in a forest area, once a month for 3 months. The phlebotomines identified were compared with climate data using simple linear correlation, Pearson's correlation coefficient and cross-correlation. The estimate of ecological parameters was calculated according to the Shannon-Wiener diversity index, standardized index of species abundance and the dominance index. RESULTS: A total of 75,499 phlebotomines belonging to 11 species were captured in the CDC traps, the most abundant being Evandromyia walkeri, Psychodopygus wellcomei and Lu. longipalpis. Evandromyia walkeri abundance was most influenced by temperature at collection time and during the months preceding collection and rainfall during the months preceding collection. Psychodopygus wellcomei abundance was most affected by rainfall and relative humidity during the collection month and the month immediately preceding collection time. Lutzomyia longipalpis abundance showed a correlation with temperature and the rainfall during the months preceding collection time. The Shannon trap contained a total of 3914 phlebotomines from these different species. Psychodopygus wellcomei, accounting for 91.93% of the total, was anthropophilic and active mainly at night. CONCLUSIONS: Most of the species collected in the traps were seasonal and exhibited changes in their composition and population dynamics associated with local adaptions. The presence of vectors Ps. wellcomei and Lu. longipalpis underscore the epidemiological importance of these phlebotomines in the conservation unit and surrounding anthropized areas. Neighboring residential areas should be permanently monitored to prevent VL or CL transmission and outbreaks.

Haemagogus spegazzinii Brèthes, 1912 (Diptera: Culicidae) in Brazilian semiarid: resistance in eggs and scale color variation in adults

ABSTRACT Although aedine eggs are resistant to desiccation, little is known about this trait in Haemagogus species. In this study, we assessed the desiccation resistance of Hg. spegazzinii eggs. The eggs were collected using ovitraps over a period of one week in March 2020. The positive pallets were stored until experimentation and immersed in a solution of water and yeast for larval hatching and subsequent species identification. The emerged adults were morphologically identified as Hg. spegazzinii. Because of color variations, adults were classified into three groups. The desiccation resistance of the eggs collected was measured for 380 days. Desiccation resistance is likely the result of selection mechanisms responsible for maintaining populations of the species in the seasonally dry tropical forest (Caatinga) in the Brazilian semiarid region. Variations in scale coloration can represent either individual variations or new species.

Ecological relationships of Haemagogus spegazzinii (Diptera: Culicidae) in a semiarid area of Brazil.

INTRODUCTION: Haemagogus are mosquitoes with diurnal habits that live preferentially in forest areas. In Brazil, they are considered the primary vectors of wild yellow fever. METHODS: The ecological relationships between Haemagogus spegazzinii, the environment, and some of its activities in the semiarid region of Rio Grande do Norte were analyzed by collecting eggs with ovitraps, actively searching in tree holes, capturing adults in Shannon traps, and conducting an investigation for viral infections. RESULTS: A total of 2420 eggs, 271 immature specimens (larvae and pupae), and 206 adults were collected. Egg collection depended on rainfall and relative humidity, with oviposition occurring between January and May. Larvae were found in five plant species, including Tabebuia aurea (craibeira), with 160 larvae collected. We observed shared breeding sites between Hg. spegazzinii and the following species: Aedes albopictus, Aedes terrens, Culex spp., and Toxorhynchites theobaldi. Adults exhibited greater activity between 5 pm and 6 pm, when 191 (92.7%) specimens were captured, while only 1 (0.5%) was collected between 7 pm and 8 pm. The relationship between Hg. spegazzinii and rainfall was significant, with positive correlations with accumulated rainfall 5, 10, 15, 20, and 30 days before mosquito collection. We found that the species was infected with the DENV-2 virus. CONCLUSIONS: This work contributes new information on the bioecology of Hg. spegazzinii, with data on the main reproduction periods, oviposition, breeding sites, activity times, and the relationship between the species and meteorological variables in the Caatinga of northeastern Brazil.

Ecological relationships of Haemagogus spegazzinii (Diptera: Culicidae) in a semiarid area of Brazil

Abstract INTRODUCTION: Haemagogus are mosquitoes with diurnal habits that live preferentially in forest areas. In Brazil, they are considered the primary vectors of wild yellow fever. METHODS: The ecological relationships between Haemagogus spegazzinii, the environment, and some of its activities in the semiarid region of Rio Grande do Norte were analyzed by collecting eggs with ovitraps, actively searching in tree holes, capturing adults in Shannon traps, and conducting an investigation for viral infections. RESULTS: A total of 2420 eggs, 271 immature specimens (larvae and pupae), and 206 adults were collected. Egg collection depended on rainfall and relative humidity, with oviposition occurring between January and May. Larvae were found in five plant species, including Tabebuia aurea (craibeira), with 160 larvae collected. We observed shared breeding sites between Hg. spegazzinii and the following species: Aedes albopictus, Aedes terrens, Culex spp., and Toxorhynchites theobaldi. Adults exhibited greater activity between 5 pm and 6 pm, when 191 (92.7%) specimens were captured, while only 1 (0.5%) was collected between 7 pm and 8 pm. The relationship between Hg. spegazzinii and rainfall was significant, with positive correlations with accumulated rainfall 5, 10, 15, 20, and 30 days before mosquito collection. We found that the species was infected with the DENV-2 virus. CONCLUSIONS: This work contributes new information on the bioecology of Hg. spegazzinii, with data on the main reproduction periods, oviposition, breeding sites, activity times, and the relationship between the species and meteorological variables in the Caatinga of northeastern Brazil.

Anthropophily of Lutzomyia wellcomei (Diptera: Psychodidae) in an Atlantic Forest Conservation Unit in Northeast Brazil.

Lutzomyia wellcomei (Fraiha, Shaw & Lainson) (Diptera: Psychodidae) can act as an important vector of Leishmania (Viannia) braziliensis This study presents the results of collections carried out in a fragment of Atlantic Forest in a Conservation Unit of Rio Grande do Norte state. Collections occurred over 12 consecutive months using Shannon and CDC traps. A total of 777 sand flies from eight species were collected: Lutzomyia walkeri (Newstead), Lutzomyia evandroi (Costa Lima & Antunes), Lutzomyia wellcomei (Fraiha, Shaw & Lainson), Lutzomyia sordellii (Shannon & Del Ponte), Lutzomyia brasiliensis (Costa Lima), Lutzomyia lenti (Mangabeira), Lutzomyia longipalpis (Lutz & Neiva), and Lutzomyia abonnenci (Floch & Chassignet). Lutzomyia wellcomei was the most abundant species using the Shannon trap (97%) and L. walkeri in the CDC trap (81%). It is important to note the abundance of L. wellcomei in Shannon trap collections, which favors the capture of anthropophilic species. Lutzomyia wellcomei was only present in months where rainfall was above 100 mm, confirming it as a species adapted to wetter months.

Sand flies (Diptera, Psychodidae, Phlebotominae), vectors of Leishmania protozoa, at an Atlantic Forest Conservation Unit in the municipality of Nísia Floresta, Rio Grande do Norte state, Brazil.

BACKGROUND: Sand flies are insect vectors of protozoa from the genus Leishmania, causative parasites of visceral and American tegumentary leishmaniases. The present study discusses the bioecological aspects of sand fly species, transmitters of Leishmania protozoa, in different ecotopes of an Atlantic Forest Conservation Unit located in the metropolitan region of Natal, Rio Grande do Norte state, Brazil. METHODS: Two monthly captures were made in 1 year, using CDC light traps, in two anthropized and two preserved environments. RESULTS: A total of 2936 sand flies belonging to the following ten species were captured: Evandromyia walkeri, Evandromyia evandroi, Psychodopygus wellcomei, Sciopemyia sordellii, Psathyromyia brasiliensis, Lutzomyia longipalpis, Evandromyia lenti, Psathyromyia shannoni, Nyssomyia whitmani and Nyssomyia intermedia. The most common species was E. walkeri (77.6%), followed by E. evandroi (17.5%). Forest was the site with the greatest abundance (32.4%), followed by bamboo grove (26.3%). CONCLUSIONS: Sand flies were generally more abundant in the rainy season and L. longipalpis, a vector species of Leishmania infantum, was adapted to anthropized environments. It was confirmed that P. wellcomei, a vector of Leishmania braziliensis in Amazônia, is a species associated with more preserved environments, and occurs only in the rainy season.

Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes

Abstract Zika virus, already widely distributed in Africa and Asia, was recently reported in two Northeastern Brazilian: State of Bahia and State of Rio Grande do Norte, and one Southeastern: State of São Paulo. This finding adds a potentially noxious virus to a list of several other viruses that are widely transmitted by Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus in Brazil. The pathology and epidemiology, including the distribution and vectors associated with Zika virus, are reviewed. This review is focused on viruses transmitted by Aedes (Stegomyia) mosquitoes, including dengue, Chikungunya, Zika, Mayaro, and yellow fever virus, to emphasize the risks of occurrence for these arboviruses in Brazil and neighboring countries. Other species of Aedes (Stegomyia) are discussed, emphasizing their involvement in arbovirus transmission and the possibility of adaptation to environments modified by human activities and introduction in Brazil.

Zika virus in Brazil and the danger of infestation by Aedes (Stegomyia) mosquitoes.

Zika virus, already widely distributed in Africa and Asia, was recently reported in two Northeastern Brazilian: State of Bahia and State of Rio Grande do Norte, and one Southeastern: State of São Paulo. This finding adds a potentially noxious virus to a list of several other viruses that are widely transmitted by Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus in Brazil. The pathology and epidemiology, including the distribution and vectors associated with Zika virus, are reviewed. This review is focused on viruses transmitted by Aedes (Stegomyia) mosquitoes, including dengue, Chikungunya, Zika, Mayaro, and yellow fever virus, to emphasize the risks of occurrence for these arboviruses in Brazil and neighboring countries. Other species of Aedes (Stegomyia) are discussed, emphasizing their involvement in arbovirus transmission and the possibility of adaptation to environments modified by human activities and introduction in Brazil.

Seasonal variation of potential flavivirus vectors in an urban biological reserve in northeastern Brazil.

Although yellow fever (YF) has not been reported on the eastern coast of Brazil since 1942, there was a reemergence of dengue fever in Brazil in 1987 due to the reintroduction of Aedes aegypti (L.). To assess areas of potential risk for transmission of vector-borne diseases, a surveillance system was placed in a large Atlantic Forest reserve in Natal, Rio Grande do Norte, Brazil, where in 2004 unexplained epizootics were reported among marmosets. The etiologic agent causing the mortality in marmosets has not been identified. Wyeomyia bourrouli Lutz, Haemagogus leucocelaenus Dyar & Shannon, Ae. aegypti, Aedes albopictus (Skuse), Ochlerotatus scapularis Rondani, Ochlerotatus serratus Theobald, Ochlerotatus taeniorhynchus Wiedemann, Culex quinquefasciatus Say, and Limatus durhami Theobald were collected in the park and in the proximity of the households adjacent to the park. Seasonal abundance fluctuation was significant for Ae. aegypti, Ae. albopictus, Ochlerotatus scapularis (Rondani), and Hg. leucocelaenus. Eggs of Ae. aegypti, Ae. albopictus, and Hg. leucocelaenus were more frequently found at the conclusion of the rainy season. A significant negative correlation between the number ofAe. albopictus collected and temperature was observed (r = -0.50), i.e., for each 10C increase in temperature, the number of specimens collected decreased eight-fold. The findings reported herein reinforce the need for a sustainable arboviral surveillance program in this area to decrease the potential risk of emergence of vector borne diseases as YF.

Experimental infection parameters in Galea spixii (Rodentia: Caviidae) with Leishmania infantum chagasi.

In order to better understand the epidemiological transmission network of leishmaniasis, an endemic disease in Northeast Brazil, we investigated the susceptibility of Spix yellow-toothed cavies (Galea spixii) to the Leishmania infantum chagasi parasite. Nine cavies were experimentally infected, separated into three groups and monitored at 30, 90 and 180 days, respectively. Amastigotes were identified in the spleen slides of two cavies killed 180 days after infection. Antibodies against the L. i. chagasi were identified in one of the cavies. This demonstrates that G. spixii is in fact capable of maintaining a stable infection by L. i. chagasi without alterations in biochemical and hematological parameters of the host and without perceivable micro and macroscopic lesions.

Experimental infection parameters in Galea spixii (Rodentia: Caviidae) with Leishmania infantum chagasi

In order to better understand the epidemiological transmission network of leishmaniasis, an endemic disease in Northeast Brazil, we investigated the susceptibility of Spix yellow-toothed cavies (Galea spixii) to the Leishmania infantum chagasi parasite. Nine cavies were experimentally infected, separated into three groups and monitored at 30, 90 and 180 days, respectively. Amastigotes were identified in the spleen slides of two cavies killed 180 days after infection. Antibodies against the L. i. chagasi were identified in one of the cavies. This demonstrates that G. spixii is in fact capable of maintaining a stable infection by L. i. chagasi without alterations in biochemical and hematological parameters of the host and without perceivable micro and macroscopic lesions.

Effect of abiotic factors on seasonal population dynamics of Lutzomyia longipalpis (Diptera: Psychodidae) in northeastern Brazil.

The resurgence of visceral leishmaniasis in Brazil increases the need for studies to elucidate the spatial and temporal dynamics of Lutzomyia longipalpis (Lutz and Neiva) (Diptera: Psychodidae), the vector of Leishmania infantum, the causative agent of visceral leishmaniasis in Brazil. Sand flies were captured in peridomestic habitats biweekly for 3 yr. Cross-correlation tests and spectral analysis were used to analyze the simultaneous and lag-time correlations between Lu. longipalpis population densities and abiotic factors of temperature, relative humidity, wind velocity, and rainfall. Distinct seasonal patterns were observed for males and females, with intervals of 6 mo between population peaks for males and 12 mo for females. Peak female population densities lagged 3 mo behind the maximum annual temperature. Female population density was negatively correlated with relative humidity. An increase in average wind velocity was followed by a decrease in the number of females for 2 wk. Understanding the relationship between the seasonal population dynamics of Lu. longipalpis and abiotic factors will contribute to the design of better control measures to decrease transmission of L. infantum and consequently the incidence of leishmaniasis.

Characteristics of the bological cycle of Lutzomyia evandroi Costa Lima & Antunes, 1936 (Diptera: Psychodidae) under experimental conditions

Lutzomyia evandroi Costa Lima and Antunes, 1936 is found in Rio Grande do Norte, northeastern Brazil, in areas of visceral and mucocutaneous leishmaniasis and follows the same geographic distribution of L. longipalpis. The biological cycle, oviposition, morphological and behavioral characteristics of the species were studied under experimental conditions. The average number of eggs per wild caught female varied from 21 to 50 eggs along the year, with a peak occurring between January and March and another in August, with oviposition lasting for 4 to 12 days. The mean larval phase was 24 days. Ovipositing rates were influenced by rainfall and temperature indexes, with an increase of eggs per oviposition at the beginning and at the end of the rainy season, and a decrease at the peak of the rainy season

Density of Sand Flies (Diptera: Psychodidae) in Domestic and Wild Animal Shelters in an Area of Visceral Leishmaniasis in the State of Rio Grande do Norte, Brazil

The objective of the present study was to determine the association of sand flies with the presence of domestic and wild animals in the peridomiciliary area. The sand flies were collected using direct aspiration and CDC light traps placed in animal shelters. The results suggest that different sand flies species have different behavioral characteristics in an apparent preference for animal baits and that Lutzomyia longipalpis and Lu. evandroi were the most eclectic species regarding their biotope choice. Lu. longipalpis showed a distinct preference for horses and Lu. evandroi for armadillos