RESUMO
BACKGROUND: The search for attractive baits that may facilitate the capture of haematophagous insects has been epidemiologically relevant. Sand flies use chemical cues in different phases of their life cycles to find carbohydrate meals, mates, blood meals and oviposition sites. Few studies have related the behaviours of sand flies with volatile compounds that can influence their life cycles. Previous studies in our laboratory have shown that 1-hexanol released on filter paper is a good attractant for the sand fly Nyssomyia neivai, which is suspected in the transmission of the aetiologic agent of American cutaneous leishmaniasis. METHODS: In this study, we developed two release systems to modulated 1-hexanol release: system 1 contained gellan gum and pectin (4:1 ratio), 3% aluminium chloride and 1% glutaraldehyde; system 2 contained: gellan gum and pectin (4:1 ratio) and 3% aluminium chloride. After addition of 1-hexanol to each release system, trials were performed in a wind tunnel with Ny. neivai males and females (unfed, blood-fed and gravid) to evaluate activation and attraction responses. RESULTS: Males and unfed females showed the same response pattern to the systems. For both systems, the males and unfed females of the sand flies showed an activation response up to 24 h. The number of responsive gravid females was lower than unfed females for both systems. The blood-fed females showed no responses in any of the release systems. CONCLUSIONS: Our findings indicate that the state of the females (unfed, fed and gravid) can interfere with the sand fly responses to volatile compounds. Additionally, both systems evaluated with the compound showed effectiveness for sand fly attraction.
Assuntos
Phlebotomus , Psychodidae , Cloreto de Alumínio , Animais , Feminino , Glutaral , Hexanóis , Masculino , Pectinas , Psychodidae/fisiologiaRESUMO
BACKGROUND: Phlebotomine sand flies are vectors for several pathogens, with Leishmania being the most important. In Brazil, the main aetiological agent of American cutaneous leishmaniasis (ACL) is Leishmania (Viannia) braziliensis, and Nyssomyia neivai is one of its main vectors in São Paulo state and other areas of South America. Similar to other haematophagous insects, sand flies use volatile compounds called kairomones to locate their hosts for blood meals. A possible increase in the attractiveness of hosts infected with Leishmania infantum to their vectors has been demonstrated. In the present study, we aimed to investigate whether L. braziliensis-infected hosts present higher attractiveness to Ny. neivai and to identify differences in the volatile compounds released by infected and uninfected mice. RESULTS: Behavioural experiments in which sand fly females directly fed on infected or uninfected mice showed no significant differences in the attractiveness of the mice or the blood volume ingested. Y-tube olfactometer bioassays also revealed no significant differences in the attractiveness of these hosts to Ny. neivai. No differences were observed in the profiles of the volatile compounds released by the two groups of mice. However, PCA and cluster analysis were able to classify the 31 identified compounds into three clusters according to their abundances. This classification showed a possible role for individual variation in the absence of differences in volatile profiles and attractiveness between infected and uninfected mice. CONCLUSION: In this first cross-sectional study with an aetiological agent of ACL, there were no statistically significant differences in the attractiveness of infected hosts to their vector.
Assuntos
Comportamento Alimentar , Mordeduras e Picadas de Insetos , Insetos Vetores/fisiologia , Leishmania braziliensis , Leishmaniose Cutânea/transmissão , Psychodidae/fisiologia , Animais , Comportamento Animal , Bioensaio , Brasil , Análise por Conglomerados , Estudos Transversais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Feromônios/química , Phlebotomus , Análise de Componente Principal , OlfatoRESUMO
The information in this protocol covers from the basic steps and material necessary to start a sand fly colony up to the specific details which are important to the success of a Nyssomyia neivai colony. The greatest problems in our colony of Ny. neivai were solved with specific care, for instance, using vermiculite and an adequate number of adults in oviposition containers; the control of fungus with the exact amount of diet for the larvae and humidity control; a second blood meal for females and control of the number of times animals are used for blood meals. Currently, our colony is at F22 generation.
Assuntos
Animais de Laboratório/crescimento & desenvolvimento , Cruzamento/métodos , Larva/crescimento & desenvolvimento , Psychodidae/crescimento & desenvolvimento , Animais , FemininoRESUMO
Sand flies are natural hosts of various microorganisms. Due to their epidemiological importance, sand fly colonies are kept in laboratories to be studied in terms of their biology and vector/host/parasite interactions. In order to investigate the presence of oviposition pheromones in Nyssomyia neivai, experiments using Solid Phase Microextraction (SPME) were performed. However, siloxanes which is an external class of contamination, present in breeding containers made by plaster used to maintain sand flies in colonies, may be hindered the experiments.
Assuntos
Artefatos , Sulfato de Cálcio/química , Oviposição , Feromônios/isolamento & purificação , Psychodidae/química , Psychodidae/fisiologia , Siloxanas/análise , Microextração em Fase Sólida , Animais , Sulfato de Cálcio/análise , Feminino , Psychodidae/parasitologiaRESUMO
BACKGROUND: The most critical phase in sand fly colonization is the high mortality in the larval instars. In this study, we sought out strategies for improving the colonization of Nyssomyia neivai, one of the vectors of cutaneous leishmaniasis agent in South America. METHODS: A colony of Ny. neivai was established in the laboratory from a field population, and the productivity of adults was evaluated considering carrying capacity, diet for larvae and surface for oviposition. RESULTS: The highest emergency rate of adults was achieved with the fewest couples inside 150 mL rearing chambers on a sterilized diet made of rabbit feces, rabbit food, soil and fish food and with vermiculite as a substrate for oviposition and the development of larvae. CONCLUSION: Our data on Ny. neivai colonization showed that the best adult productivities were achieved with fewer couples inside the rearing chambers; smaller rearing containers of 150 mL (due to less fungi growth); sterilized diet made of rabbit feces, rabbit food, soil and fish food; and vermiculite as the substrate for oviposition and development of larvae.
Assuntos
Criação de Animais Domésticos/métodos , Laboratórios , Psychodidae/fisiologia , Ração Animal , Animais , Fezes/microbiologia , Feminino , Larva , Oviposição , CoelhosRESUMO
BACKGROUND: Similar to other hematophagous insects, male and female sand flies must feed on plants to obtain sugar and, subsequently, energy to complete their life cycles. A large number of compounds emitted by plants may act as volatile signals to these insects. Primary alcohols have been detected in some plants, but in small amounts. In a previous report, the attractiveness of saturated primary alcohols with 7 to 9 carbons was evaluated for Lutzomyia longipalpis, the vector of American visceral leishmaniasis, with positive results. METHODS: In the present study, a wide range of primary alcohols, 3 to 10 carbons, were tested to investigate their attractiveness to another sand fly species, Nyssomyia neivai, a putative vector of American cutaneous leishmaniasis. The mixture of compounds that induced the best sand fly response was also evaluated. RESULTS: Of the eight compounds evaluated, hexanol and octanol elicited the best attractive responses for sand fly females. CONCLUSION: Phytochemicals may be an interesting source of search for new sand fly attractants.
Assuntos
Álcoois/metabolismo , Comportamento Animal/fisiologia , Insetos Vetores/fisiologia , Feromônios/metabolismo , Compostos Fitoquímicos/farmacologia , Psychodidae/fisiologia , Álcoois/química , Animais , Feminino , Leishmaniose Cutânea/transmissão , Masculino , Compostos Fitoquímicos/químicaRESUMO
The feeding behavior of sand flies provides valuable information about the vector/host interactions and elucidates the epidemiological patterns of American cutaneous leishmaniasis (ACL) transmission. The aim of this study was to identify the blood meal sources of sand flies in endemic areas of leishmaniasis in Paraná State through polymerase chain reaction (PCR) amplification of a prepronociceptin (PNOC) gene fragment and its subsequent DNA sequencing. Moreover, molecular assays were conducted to evaluate the sensitivity and reproducibility of the PNOC gene amplification. Besides that, a time-course digestion test of the blood using sand flies that fed artificially on BALB/c mice was performed. Of 1263 female sand flies collected in the field, 93 (3.6%) specimens were engorged and 27 allowed efficient amplification of the PNOC gene. These flies had fed on equine (Equus caballus), porcine (Sus scrofa) and canine (Canis lupus familiaris) species. The results also showed that the identification of the blood meal sources of the sand flies using the molecular method was directly linked to the level of digestion of the blood (time-course) and not to the amount of blood that had been ingested or to the presence of inhibitors in the blood.