Field comparison of broad-spectrum white LED-baited traps with narrow-spectrum green LED-baited traps in the capture of Anopheles mosquitoes (Diptera: Culicidae).

Light-Emitting Diodes (LEDs) have been effective light sources in attracting Anopheles mosquitoes, but the broad-spectrum white light, even with a wide-ranging application in lighting, have not been evaluated yet. In this study, the white light was field evaluated against the green one in the light trapping of anopheline mosquitoes by using two non-suction Silva traps and two CDC-type suction light traps. Anopheline mosquitoes were captured for two 21-night periods of collecting (2022 and 2023). In the first period, two LEDs were used per Silva trap, but three were used in the second one to increase the luminance/illuminance at traps. A CDC-type suction light trap equipped with an incandescent lamp was used in 2022 and a CDC-type suction light trap equipped with a 6 V-white light (higher luminance/illuminance) in 2023. A total of eight species and 3,289 specimens were captured in both periods. The most frequent species were Anopheles triannulatus s.l., An. goeldii, An. evansae and An. argyritarsis. In 2022, white LEDs were less attractive to anopheline mosquitoes than the other light sources, but without statistical difference among treatments (F = 2.703; P = 0.0752; df = 2). In 2023, even with an increased luminance/illuminance at traps, no statistical difference was found between the two LED-baited Silva traps (F = 6.690; P = 0.0024; df = 2), but rather between the 6 V-white-baited CDC-type suction light trap and green-baited Silva traps. Due to some drawbacks and the lower abundance of individuals caught by using white LEDs, the narrow-banded green LEDs is preferable to white ones for attracting anophelines.

Field evaluation of a new suction light trap for the capture of phlebotomine sand flies (Diptera: Psychodidae: Phlebotominae), vectors of leishmaniasis.

Phlebotomine sand flies are crepuscular and nocturnal small dipteran insects in the family Psychodidae. Several disease agents, including Leishmania parasites, are transmitted to humans and other vertebrate hosts by the bite of an infected female sand fly. As part of leishmaniasis surveillance programs, light traps have been routinely used in sand fly collections. In this context, new trapping devices are always being required to improve vector monitoring. Here, the efficiency of a new suction light trap, named Silva suction trap or SS trap, was field evaluated in collecting sand flies. Two SS traps, one with green (520 nm, 15,000 mcd) and the other with white (wide spectrum, 18,000 mcd) LEDs, and one CDC-type trap were deployed in a rural forested environment. A total of 4686 phlebotomine sand flies were captured. The most frequent species were females of the Ps. Chagasi series (77.8%) followed by males of Ps. wellcomei (11.6%), Nyssomyia whitmani (3.3%), and Bichromomyia flaviscutellata (2.4%). The CDC-type light trap collected 101.9 ± 20.89 sand flies and 14 species, followed by the white-baited SS trap (87.78 ± 16.36, 14), and the green-baited SS trap (70.61 ± 14.75, 15), but there were no statistically significant differences among traps. A discussion on the considerable advantages of the use of SS traps over CDC traps is included. In this study, the Silva suction trap proved to be efficient and can be an alternative to CDC traps for monitoring adult phlebotomine sand fly populations.

The evening crepuscular host-seeking activity of Anopheles mosquitoes in northeast Brazil.

Studies on the timing of anopheline host-seeking are important for understanding mosquito ecology, behaviors, and possible role in disease transmission. To study the evening crepuscular host-seeking activity of anophelines and the effects of moonlight, anopheline mosquitoes were collected with light traps settled in a livestock area in the Brazilian Cerrado region. Traps (Silva traps) were placed next to animal enclosures at 1.5 m asl. The research was divided in 2 experiments: the first experiment (12 nights) comprised 2 trapping periods, one from 6 PM to 7 PM and one from 7 PM to 6 AM, and the second experiment (16 evenings) divided in three 20-min intervals based on the 3 twilight phases (civil: 6-6:20 PM; nautical: 6:20-6:40 PM; and astronomical: 6:40-7 PM). A total of 2,815 anopheline mosquitoes and 9 species were found. The main species were Anopheles triannulatus s.l., An. argyritarsis, An. goeldii, and An. evanse. Host-seeking mosquitoes were more frequently active during the first hour after sunset, with a significant peak in the second 20-min interval. After that, a decrease in the number of individuals was observed from the astronomical twilight onwards. Moonlight did not affect the evening flight activity of anophelines. By using LED-based passive light traps, the evening arrival time of anophelines at blood-feeding sites was demonstrated, and it may be a key time window for malaria vector control interventions.

Effect of ultraviolet LED and trap height on catches of host-seeking anopheline mosquitoes by using a low-cost passive light trap in northeast Brazil.

Light traps have been widely used for monitoring malaria vectors, although drawbacks remain. In this context, new tools and attractants are always becoming available to perform monitoring tasks, like the Silva trap, a passive and low-cost LED-light trap for host-seeking anopheline mosquitoes. In this work, the effectiveness of the Silva trap by using UV-LED and at different heights as well as a comparison with the conventional CDC-type (HP) light trap was studied. A total of 9009 mosquitoes and nine species were caught, Anopheles triannulatus, An. argyritarsis, and An. goeldii being the most frequent species. The green (520 nm) and blue (470 nm) LEDs attracted almost equal numbers of anopheline mosquitoes, but UV LEDs (395 nm) attracted a significantly lower number of individuals (Kruskal-Wallis = 19.68, P = 0.0001). Even with the predominance of mosquitoes trapped at the height of 1.5 m, no significant statistical difference was found among the four heights tested (0.5 m; 1.0 m; 1.5 m; 2.0 m). Green-baited Silva traps collected significantly more individuals than incandescent-baited CDC-type traps (U = 60.5; P = 0.0303). LEDs have been useful as light sources for attracting insect vectors and together with a low-cost trap, as the Silva trap, a feasible alternative to conventional trap-based monitoring Anopheles mosquitoes that can be implemented in the field.

Influence of Moonlight on Male Mating Aggregations of Nyssomyia whitmani, a Vector of American Cutaneous Leishmaniasis in Brazil.

Nyssomyia whitmani (Antunes & Coutinho) is the sandfly vector of causative agents of American cutaneous leishmaniasis in South and Central America. It is widely spread throughout Brazil, in a close association with domestic animals. Almost nothing is known about male mating aggregations in N. whitmani, let alone the influence of moonlight on this behavior. Thus, the influence of moonlight on male N. whitmani aggregations was investigated by using non-attractant suction traps deployed in chicken cages under full moon and new moon nights. In this 18-night study, 2,160 specimens and seven species were collected. The most frequent species was N. whitmani accounting for 91.48% of the total sample. The abundance of males of N. whitmani was significantly higher in the presence than in the absence of moon. The sex ratio on new moon nights was 1:1 (M:F) and on full moon nights was male-biased (1.7:1). Based on this study, an influence of moonlight on male mating aggregations of N. whitmani was verified. The extent of this influence on increasing sandfly aggregation at hosts, the moonlight influence on the early flight activity of male sandflies and the use of chickens as aggregation sites for males of N. whitmani, are all discussed.

Exploiting the Synergistic Effect of Kairomones and Light-Emitting Diodes on the Attraction of Phlebotomine Sand Flies to Light Traps in Brazil.

The synergistic effect of light-emitting diodes (LEDs) and kairomones on the attraction of sand flies to light traps was evaluated. Octenol and lactic acid were used as chemical attractants. Green LEDs and the incandescent lamps were used as light attractants. Five CDC-type light traps with the respective combination of attractants (incandescent lamp, incandescent lamp + chemical attractant, green LED, green LED + chemical attractant, and chemical attractant alone [without light]) were set between 18:00 and 06:00 following a Latin square design. A total of 6,536 sand flies and 16 species were collected. The most frequent species collected was Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera, Psychodidae) accounting for 43.21% of all individuals. Order of success (mean, SD) of lactic acid attractant fly capture was as follows: LED + lactic acid (36.83 ± 4.74), LED alone (34.87 ± 4.61), incandescent lamp + lactic acid (22.80 ± 3.19), incandescent lamp alone (12.67 ± 2.03), and lactic acid (0.46 ± 0.13). Order of success of octenol attractant fly capture was as follows: LED + octenol (37.23 ± 5.61), LED alone (35.77 ± 5.69), incandescent lamp + octenol (18.63 ± 3.28), incandescent lamp alone (14.67 ± 2.86), and octenol alone (1.80 ± 0.65). With exception of lactic acid + incandescent light, chemical synergists played no part in significantly increasing light trap capture of phlebotomine sand flies. However, the use of LEDs, with or without such attractants, provided significantly higher capture compared to the incandescent lamp with or without such chemicals, showing that LEDs are suitable and efficient light sources for surveillance and monitoring of phlebotomine sand flies in Brazil.

Field performance of a low cost, simple-to-build, non-motorized light-emitting diode (LED) trap for capturing adult Anopheles mosquitoes (Diptera: Culicidae).

In this paper, a non-powered trap equipped with light-emitting diodes (LEDs) designed for capturing small night-flying insects was field-evaluated for sampling anopheline mosquitoes. This new light trap, referred to as the Silva trap, was compared with the Centers for Disease Control and Prevention (CDC) miniature light trap in a livestock area in northeastern Brazil. Light traps were operated from 18:00 to 06:00 between July and August 2018, over a 12-night period. A total of 3124 specimens and eight species were collected. Anopheles (Nyssorhynchus) argyritarsis was the prevalent species, followed by A. (Nys) triannulatus s.l., A. (Nys) goeldii, A. (Nys) evansae, A. (Nys) rangeli, A. (Nys) galvaoi, A. (Nys) darlingi and A. (Nys) albitarsis s.l. The total number of anopheline mosquitoes captured with the Silva trap was higher than the number of individuals captured with the CDC light trap, but no significant difference between the two trapping methods was found. Concerning the damaged specimens, the Silva trap damaged significantly less mosquitoes than the CDC light trap. According to these results, the Silva trap has acceptable performance in being an efficient tool for sampling anopheline mosquitoes, mainly in comparison with the CDC light trap. The Silva trap has a number of advantages over other trapping devices that collect questing mosquitoes and these advantages are pointed out and discussed.

Centers for Disease Control-type light traps equipped with high-intensity light-emitting diodes as light sources for monitoring Anopheles mosquitoes.

In this study the phototactic response of anopheline mosquitoes to different luminous intensity light-emitting diodes (LEDs) was investigated. Centers for Disease Control-type light traps were changed by replacement of the incandescent lamps by 5 mm round type green (520 nm) and blue (470 nm) LEDs of different luminous intensities: green-LED traps with luminous intensities of 10,000, 15,000 and 20,000 millicandela (mcd) and the blue-LED traps with luminous intensities of 4000, 12,000 and 15,000 mcd. Our data showed that increasing luminous intensity has an effect on the attraction of anopheline mosquitoes to light traps, highlighting the importance of taking LEDs and light sources of high luminous intensity into account when using light-trap collections in monitoring populations of Anopheles species.

Evaluation of light-emitting diodes as attractant for sandflies (Diptera: Psychodidae: Phlebotominae) in northeastern Brazil.

Hoover Pugedo light traps were modified for use with green and blue-light-emitting diodes to trap phlebotomine sandflies in northeastern Brazil. A total of 2,267 specimens belonging to eight genera and 15 species were sampled. The predominant species were Nyssomyia whitmani(34.41%) and Micropygomyia echinatopharynx(17.25%).The green LED trap prevailed over the blue and control lights; however, no statistically significant difference could be detected among the three light sources. Even without statistical significance, we suggest using LEDs as an attractant for the capture of sandflies because of several advantages over the conventional method with incandescent lamps.

Flebotomíneos (Diptera: Psychodidae) associados a abrigos de animais domésticos em área rural do Nordeste do estado do Mranhão, Brasil / Sand flies (Diptera: Psychodidae) Associated with Domestic Animal Shelters in a Rural Area of Northestern Maranhão, Brazil

Na zona rural do município de Chapadinha, nordeste do estado do Maranhão, os abrigos de animaisdomésticos são frequentes e próximos tanto das residências quanto das áreas de mata. A criação de bovinos, que também é comum, altera a vegetação local, criando condições para o processo de domiciliação de espécies de flebotomíneos encontradas nas áreas florestadas. Este estudo teve porobjetivo conhecer a associação dos flebotomíneos com os abrigos de animais domésticos em área rural do estado do Maranhão. Os insetos foram amostrados mensalmente de janeiro a dezembro de 2010, das 18h às 6h, com armadilhas luminosas do tipo CDC, instaladas em ambiente peridomiciliar:uma no curral bovino, uma no galinheiro e a outra no chiqueiro. Foram capturados 1.190 indivíduos de 10 espécies, sendo as mais frequentes Lutzomyia evandroi (90,6por cento; n igual 1.078), L. termitophila (2,8por cento; n igual 33), L. longipalpis (2,4por cento; n igual 29) e L. whitmani (2,4por cento; n igual 28). O galinheiro foi o abrigo que apresentou maior número de indivíduos (88por cento). Lutzomyia evandroi foi a espécie mais frequente no galinheiro (94,8por cento). No abrigo curral, as espécies mais prevalentes foram L. evandroi (57,1por cento), L. longipalpis (23,1por cento) e L. whitmani (11por cento). A espécie mais frequente no chiqueiro foi L. evandroi (63,5por cento). Em geral os flebotomíneos não mostraram preferência por abrigo, salvo L. longipalpis, mais frequente no curral e ausente no abrigo chiqueiro.

Infecção por Giardia lamblia em crianças de 0 a 10 anos no município de Chapadinha, Maranhão, Brasil / Giardia lamblia infection in children under 10 years old in the municipality of Chapadinha, Maranhão state, Brazil

O presente trabalho teve como objetivo determinar a freqüência da infecção por Giardia lamblia dentro da faixa etária de 0 a 10 anos no município de Chapadinha, Maranhão. Os dados coproscópicos apresentados são provenientes do Laboratório Central de Chapadinha, realizados entre janeiro de 2007 e fevereiro de2008, obtidos a partir da técnica de Hoffmann, Pons e Janer (Sedimentação Espontânea). Foram analisadas 623 amostras, sendo 102 positivas para G. lamblia (16,4%), 376 negativas (60,3%) e 145 (23,2%) positivas para outros enteroparasitas. Os menores valores de infecção por G. lamblia foram observadas nos indivíduos menores de 1 ano (6,8%) e os maiores em crianças de 2 a 6 anos, onde 71,5% dos casos positivos ocorreram neste intervalo etário. A freqüência das infecções por outros enteroparasitas aumentaram continuamente, principalmente após os 4 anos. O padrão de infecção em Chapadinha é semelhante ao encontrado em outras localidades, onde as taxas de infecção aumentam com a idade e alcança um pico e, em seguida, decrescem, diferindo dos valores progressivos de infecção para os outros enteroparasitas.

Flebotomíneos (Diptera, Psychodidae) de capoeira do Município do Paço do Lumiar, Estado do Maranhäo, Brasil: área de transmissäo de leishmaniose / Sandflies (Diptera, Psychodidae) in a secondary forest area in the county of Paço do Lumiar, Maranhäo, Brazil: a leishmaniasis transmission area

Apresentam-se a riqueza de espécies, a abundância relativa, a flutuaçäo sazonal e horária dos flebótomos estudados em uma capoeira da Ilha de Säo Luís - MA, área de transmissäo de leishmanioses tegumentar e visceral. Os flebótomos foram capturados em armadilha luminosa, das 18h às 6 h, uma vez por mês, de março de 1997 a fevereiro de 1998. Foram coletados 489 espécimens (251 machos e 238 fêmeas) de dez espécies: Lutzomyia antunesi (45,19 por cento), Lutzomyi whitmani (29,4 por cento), Lutzomyia longipalpis (7,56 por cento), Lutzomyia sordelli (6,34 por cento), Lutzomyia flaviscutellata (4,5 por cento), Brumptomyia avellari (4,09 por cento), Lutzomyia evandroi (1,85 por cento), Lutzomyia umbratilis (0,61 por cento), Lutzomyia corossoniensis (0,41 por cento) e Lutzomyia trispinosa (0,41 por cento). Os flebótomos estiveram presentes o ano inteiro, com maior abundância na estaçäo chuvosa (janeiro a junho), e em todos os horários, principalmente entre 0h e 1h.

Phlebotominae (Diptera, Psychodidae) de Lagoas, município de Buriticupu, Amazônia Maranhense: I - Riqueza e abundância relativa das espécies em área de colonizaçäo recente / Sand flies (Dpitera, Psychodidae) of Lagoas, muncipal district of Buriticupu, Amazonia of Maranhäo: I- Richness and relative abundance of the species in area of recent colonisation

Este estudo determinou a riqueza de espécies e a abundância relativa dos flebotomíneos da comunidade de Lagoas, em Buriticupu, na Amazônia Maranhense. O estudo consistiu na captura de formas adultas com auxílio de armadilhas luminosas tipo CDC e armadilha de Shannon, das 18 às 6 horas, uma ver por mês, de dezembro/95 a janeiro/97, em ambiente florestal e extraflorestal (peri e intradomicílios). No total, capturou-se 9.392 espécimens (4.302 machos e 5.090 fêmeas) distribuídos em 38 espécies (1 Brumptomyia e 37 Lutzomyia). A riqueza e abundância de espécies foram maiores na mata, seguida do peri e intradomicílio. Na mata, as espécies mais freqüentes foram Lutzomyia whitmani (64,9 por cento), L. migonei (27 por cento) e L. serrana (3,6 por cento). No peridomicílio, predominaram L. evandroi (55,4 por cento), L. whitmani (33,4 por cento) e L. migonei (6,4 por cento) e no infra, L. evandroi (97,9 por cento). O predomínio no ambiente silvestre resulta das potencialidades ainda encontradas nas glebas remanescentes da floresta täo explorada pelas atividades madeireira e agropecuária. Por outro lado, a peridomiciliaçäo de 7,7 por cento das espécies reverteu-se de grande importância epidemiológica, haja visto a existência de pacientes com leishmanioses que julgam ter adquirido a infecçäo nas proximidades de suas habitaçöes

Distribuição de Aedes aegypti e do dengue no Estado do Maranhão, Brasil / Distribution of Aedes aegypti and dengue in the State of Maranhão, Brazil

O dengue e o Aedes aegypti encontram-se disseminados em municípios de todas as regiões do Maranhão. No ano de 1995, foram trabalhados 87 dos 136 municípios em que se divide geograficamente o Estado, 176 localidades e 480.687 imóveis. Foram considerados positivos para Ae. aegypti trinta municípios (34,4 percent), 118 localidades (67,0 percent) e 10.357 imóveis (2,1 percent). Dos municípios positivos, três pertencem à Ilha de São Luís, sete à Amazônia Maranhense, 12 à zona dos cerrados meridionais, cinco à zona mista de matas-cerrados-cocais. Nas zonas que seguem - campos aluviais, matas-cocais e dunas-restinga -, Ae. aegypti foi encontrado em apenas um município. Os índices de positividade predial foram mais elevados na Amazônia Maranhense (3,5 por cento) e na Ilha de São Luís (2,5 por cento), por constituírem as rotas de maior fluxo migratório da população e de escoamento de produtos entre o Maranhão e os estados vizinhos e também por serem áreas onde estão localizados os grandes centros urbanos e econômicos do Estado. Os índices de infestação predial por Ae. aegypti e de casos de dengue notificados foram maiores nos meses úmidos, mostrando a importância das chuvas na formação de criadouros do vetor e na distribuição de Aedes e do dengue

Flebotomíneos (Diptera, Psychodidae) de área endêmica de leishmaniose na região dos cerrados, Estado do Maranhão, Brasil / Sandflies (Diptera, Psychodidae) from an endemic leishmaniasis area in the cerrado region of the State of Maranhão, Brazil

Apresentam-se dez espécies do gênero Lutzomyia França, 1924, encontradas nos cerrados do nordeste maranhense. As capturas foram realizadas das 18h às 6h, uma vez por mês, durante nove meses, nos municípios de Aldeias Altas, Capinzal do Norte, Caxias, Codó, Coelho Neto, Timbiras, Timon e Tuntum, áreas endêmicas das leishmanioses visceral e tegumentar. No total, foram capturados 1.868 espécimens em armadilhas luminosas tipo CDC, sendo 377 no intradomicílio (64,7 por cento machos e 35,3 por cento fêmeas) e 1.491 no peridomicílio (73 por cento machos e 27 percent fêmeas). As espécies encontradas foram as que seguem: Lutzomyia cortelezii, Lutzomyia evandroi, Lutzomyia goiana, Lutzomyia intermedia, Lutzomyia lenti, Lutzomyia longipalpis, Lutzomyia longipennis, Lutzomyia squamiventris, Lutzomyia termitophila e Lutzomyia whitmani. As mais abundantes no intra e no peridomicílios foram L. longipalpis (67,4 por cento e 70,2 por cento, respectivamente) e L. whitmani (31 por cento e 24,7 por cento, respectivamente). L. longipalpis ocorreu em todos os meses estudados, nas estações seca e chuvosa, e em todas as localidades trabalhadas

Flebótomos (Diptera, Phlebotominae) da Ilha de Säo Luis, zona do Golfäo Maranhense, Brasil / Phlebotomines (Diptera, Phlebotominae) in the Island of Säo Luis, Big Golf zone, Maranhäo State, Brazil

Apresenta-se uma lista de flebotomíneos com 32 espécies, sendo 1 Brumptomyia e 31 Lutzomyia, distribuídas nos subgêneros Psychodopygus (6), Nyssomyia (5), Pressatia (3), Evandromyia (2), Psathyromyia (2), Sciopemyia (2), Lutzomyia (1), Micropygomyia (1), Viannamyia (1), e nos grupos Oswaldoi (5) e Migonei (3). Os flebotomíneos foram capturados na mata, peridomicílio (chiqueiro, galinheiro e estábulo) e intradomicílio (dormitório), das 18 às 6 horas, uma vez por mês, durante 4 anos na Ilha de Säo Luis, Maranhäo. Todas as espécies ocorreram na mata, sendo que 16 também foram encontradas no peri e 11 dentro dos domicílios. Foram capturados 22.581 espécimens, sendo que 65,1 por cento ocorreram no peridomicílio, 17,5 por cento na mata e 17,4 por cento no intradomicílio. A espécie mais comum foi Lutzomyia longipalpis com 66,4 por cento dos exemplares capturados, seguida por L. whitmani (24 por cento) e L. evandroi (5,9 por cento). As 29 espécies restantes representaram apenas 3,7 por cento da amostra total