Semiochemical delivery systems based on natural polymers to attract sand flies (Diptera: Psychodidae).

BACKGROUND: The successful use of semiochemicals to attract insects to traps is based on research on the most suitable compounds and their release profiles over time. Based on the group's promising results, matrices with a more adequate release profile and more eco-friendly properties for the release of 1-hexanol were developed. To use a more suitable prototype in the field, the most promising systems were added to a capsule and evaluated in a wind tunnel. Behavioral experiments were performed using the sand fly species, Lutzomyia longipalpis, to evaluate the efficacy of the proposed system. METHODS: Different delivery systems were developed by varying the polymer (gellan gum and pectin) ratio, crosslinker (aluminum chloride) concentration, and glutaraldehyde removal.The delivery systems were loaded with 1-hexanol, and their release profiles were evaluated using gravimetric analysis under ambient and high-humidity conditions. When the matrix system was placed inside a plastic container, modulations in the active release profile were observed and the system could be reused. Actid attraction behaviors of the sand fly species, Lu. longipalpis, were evaluated in a wind tunnel when exposed to 1-hexanol-loaded release systems at different times. RESULTS: Among the four formulations evaluated, System 2 (gellan gum and pectin in a 1:1 ratio with 5% aluminum chloride) exhibited the most promising release profile, with greater uniformity and longer compound release time. The maximum 1-hexanol release uniformity was achieved over a longer time, mainly every 24 h, under both ambient and high-humidity conditions. System 2 can be reused at least once with the same structure. The wind tunnel trials exhibited efficient activation and attraction of Lu. longipalpis to 1-hexanol after 24, 48, and 72 h in System 2 placed inside the capsules. CONCLUSIONS: The polymeric matrix supplemented with 1-hexanol and introduced in plastic capsules showed promising results in attracting sand flies. This system can be used as a solution for other attractive compounds as well as in other applications where their release needs to be controlled or prolonged.

Behavioral responses of sand fly Nyssomyia neivai (Psychodidae: Phlebotominae) to 1-hexanol and light.

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.

Repellent effects of the essential oils of Cymbopogon citratus and Tagetes minuta on the sandfly, Phlebotomus duboscqi.

BACKGROUND: The sandfly, Phlebotomus duboscqi is a vector of zoonotic cutaneous leishmaniasis (ZCL) that is an important public health problem in Eastern Africa. Repellents have been used for protection of humans against vectors of ZCL and other vectors that transmit killer diseases including malaria, Rift Valley fever, dengue, and yellow fever. The repellent effects of different doses of the essential oils from the lemon grass, Cymbopogon citratus and Mexican marigold, Tagetes minuta were evaluated in a two-chamber bioassay against 3- to 7-day-old unfed females of P. duboscqi in the laboratory. The results were compared with those that were obtained when test animals were treated with an equivalent dose of diethyl-3-methylbenzamide, which is a repellent that is commonly used as a positive control. RESULTS: Overall, percentage repellency increased with increasing doses of the essential oils while biting rates decreased with increasing concentrations of the oils. Further, the oil of C. citratus was more potent than that of T. minuta with regard to protection time and biting deterrence. The effective doses at 50% (ED50) and at 90% (ED90) for the oil of C. citratus, were 0.04 and 0.79 mg/ml, respectively. Those of the oil of T. minuta were 0.10 and 12.58 mg/ml. In addition, the percentage repellency of 1 mg/ml of the essential oils of C. citratus and T. minuta against sandflies was 100% and 88.89%, respectively. A lower dose of 0.5 mg/ml of the oils, elicited 89.13% repellency for C. citratus and 52.22% for T. minuta. CONCLUSION: The laboratory tests showed that the essential oils of the two plants were highly repellent to adult sand flies, P. duboscqi. Thus, the two essential oils are candidate natural repellents that can be used against P. duboscqi due to their high efficacy at very low doses, hence, the envisaged safety in their use over chemical repellents. It remains to carry out clinical studies on human subjects with appropriate formulations of the oils prior to recommending their adoption for use against the sandflies.

Insecticidal effect of plant extracts on Phlebotomus argentipes (Diptera: Psychodidae) in Bihar, India.

BACKGROUND & OBJECTIVES: Phlebotomus argentipes (Diptera: Psychodidae), the established vector for kala-azar is presently being controlled by indoor residual spray of DDT in kala-azar endemic areas in India. Search for non-hazardous and non-toxic biodegradable active molecules from botanicals may provide cost-effective and eco-friendly alternatives to synthetic insecticides. The present study was aimed at evaluating various plant extracts from endemic and non-endemic areas of Bihar for their insecticidal activity against sandfly to identify the most effective plant extract. METHODS: Bio-assay test was conducted with larvae and adult of P. argentipes with different plant extracts collected in distilled water, hexane, ethyl acetate, acetone and methanol. Thin layer chromatography (TLC), column chromatography and high performance liquid chromatography (HPLC) were conducted for detection of active molecules. RESULTS: Adults and larvae of sandflies exposed to the aqueous extract of Nicotiana tabacum resulted in 100 per cent mortality. The hexane extract of Clerodendrum infortunatum was found to kill 77 per cent adults but was ineffective against larvae. Bio-assay test of the ninth fraction (hexane extract-methanol phase) separated by column chromatography was found to be 63 per cent effective. The purple spot on the TLC of this fraction indicated the presence of a diterpenoid. HPLC of this fraction detected nine compounds with two peaks covering 20.44 and 56.52 per cent areas with retention time of 2.439 and 5.182 min, respectively supporting the TLC results. INTERPRETATION & CONCLUSIONS: The column separated 9 [th] fraction of C. infortunatum extract was found to be effective in killing 63 per cent of adult P. argentipes. Compounds of this fraction need to be evaluated further for identification and characterization of the active molecule by conducting individual bio-assay tests followed by further fractionation and HPLC. Once the structure of the active molecule is identified and validated, it may be synthesized and formulated as a product.

Acetylcholinesterase of the sand fly, Phlebotomus papatasi (Scopoli): cDNA sequence, baculovirus expression, and biochemical properties.

BACKGROUND: Millions of people and domestic animals around the world are affected by leishmaniasis, a disease caused by various species of flagellated protozoans in the genus Leishmania that are transmitted by several sand fly species. Insecticides are widely used for sand fly population control to try to reduce or interrupt Leishmania transmission. Zoonotic cutaneous leishmaniasis caused by L. major is vectored mainly by Phlebotomus papatasi (Scopoli) in Asia and Africa. Organophosphates comprise a class of insecticides used for sand fly control, which act through the inhibition of acetylcholinesterase (AChE) in the central nervous system. Point mutations producing an altered, insensitive AChE are a major mechanism of organophosphate resistance in insects and preliminary evidence for organophosphate-insensitive AChE has been reported in sand flies. This report describes the identification of complementary DNA for an AChE in P. papatasi and the biochemical characterization of recombinant P. papatasi AChE. METHODS: A P. papatasi Israeli strain laboratory colony was utilized to prepare total RNA utilized as template for RT-PCR amplification and sequencing of cDNA encoding acetylcholinesterase 1 using gene specific primers and 3'-5'-RACE. The cDNA was cloned into pBlueBac4.5/V5-His TOPO, and expressed by baculovirus in Sf21 insect cells in serum-free medium. Recombinant P. papatasi acetylcholinesterase was biochemically characterized using a modified Ellman's assay in microplates. RESULTS: A 2309 nucleotide sequence of PpAChE1 cDNA [GenBank: JQ922267] of P. papatasi from a laboratory colony susceptible to insecticides is reported with 73-83% nucleotide identity to acetylcholinesterase mRNA sequences of Culex tritaeniorhynchus and Lutzomyia longipalpis, respectively. The P. papatasi cDNA ORF encoded a 710-amino acid protein [GenBank: AFP20868] exhibiting 85% amino acid identity with acetylcholinesterases of Cx. pipiens, Aedes aegypti, and 92% amino acid identity for L. longipalpis. Recombinant P. papatasi AChE1 was expressed in the baculovirus system and characterized as an insect acetylcholinesterase with substrate preference for acetylthiocholine and inhibition at high substrate concentration. Enzyme activity was strongly inhibited by eserine, BW284c51, malaoxon, and paraoxon, and was insensitive to the butyrylcholinesterase inhibitors ethopropazine and iso-OMPA. CONCLUSIONS: Results presented here enable the screening and identification of PpAChE mutations resulting in the genotype for insensitive PpAChE. Use of the recombinant P. papatasi AChE1 will facilitate rapid in vitro screening to identify novel PpAChE inhibitors, and comparative studies on biochemical kinetics of inhibition.

Multiple genetic divergences and population expansions of a Mediterranean sandfly, Phlebotomus ariasi, in Europe during the Pleistocene glacial cycles.

Phlebotomus ariasi is one of the two sandflies transmitting the causative agent of zoonotic leishmaniasis, Leishmania infantum, in France and Iberia, and provides a rare case study of the postglacial re-colonization of France by a Mediterranean species. Four DNA sequences were analysed-mitochondrial cytochrome b (cyt b), nuclear elongation factor-1α (EF-1α) and two anonymous nuclear loci-for 14-15 French populations and single populations from northeast Spain, northwest Spain, Portugal and Morocco. The presence of cryptic sibling species was not revealed by phylogenetic analyses and testing for reproductive isolation between sympatric populations defined by the two most divergent cyt b haplogroups. No locus was shown to be under positive directional or balancing selection and, therefore, molecular variation was explained demographically. Each nuclear locus showed shallow isolation by distance from Portugal to the French Pyrenees, but for both cyt b and EF-1α there was then a step change to the upland Massif Central, where leading-edge populations showed low diversity at all loci. Multiple genetic divergences and population expansions were detected by analyses of cyt b and dated to the Pleistocene. Endemicity of one cyt b sub-lineage suggested the presence of a refuge north of the Pyrenees during the last glacial period. Monopolization of the Massif Central by genetically differentiated populations of P. ariasi might possibly hinder the northwards spread of leishmaniasis.

The potential of the extracts of Tagetes minuta Linnaeus (Asteraceae), Acalypha fruticosa Forssk (Euphorbiaceae) and Tarchonanthus camphoratus L. (Compositae) against Phlebotomus duboscqi Neveu Lemaire (Diptera: Psychodidae), the vector for Leishmania major Yakimoff and Schokhor.

BACKGROUND & OBJECTIVES: Harmful effects of synthetic chemical insecticides including vector resistance, environmental pollution and health hazards have necessitated the current significance in the search for plant-based insecticide products that are environmentally safe and effective to leishmaniases control. The insecticidal activity of Tagetes minuta Linnaeus (Asteraceae), Acalypha fruticosa Forssk (Euphorbiaceae) and Tarchonanthus camphoratus L. (Compositae) extracts were investigated against Phlebotomus duboscqi Neveu Lemaire (Diptera: Psychodidae). METHODS: The extracts were prepared from dried aerial parts soaked in methanol and ethyl acetate twice until the filtrates became clear, filtered and dried out by rotary evaporation at 30-35 degrees C. The solid extracts obtained were later prepared into 2.5, 5 and 10 mg/ml. Two millilitres of the solutions were blotted on filter papers, which were dried overnight and placed into jars where adult sandflies were aspirated. Males and females were assayed separately. RESULTS & CONCLUSION: The extracts had significant mortality (p<0.05) in both males and females bioassays but were not significantly different between sexes. The extracts of Acalypha fruticosa and Tagetes minuta had significantly higher mortality rates than those of Tarchonanthus camphoratus and the different concentrations used showed significantly different mortality rates and 10 mg/ml was the most effective concentration. Cent percent mortality was obtained at 96 h of exposure to 5 and 10 mg/ml concentrations except for Tarchonanthus camphoratus which had a mortality of only 46.7% in 10 mg/ml bioassay. These extracts were found to be insecticidal to adult sandflies.

Laboratory and field evaluation of neem (Azadirachta indica A. Juss) and Chinaberry (Melia azedarach L.) oils as repellents against Phlebotomus orientalis and P. bergeroti (Diptera: Psychodidae) in Ethiopia.

The study evaluated the efficacy of neem (Azadirachta indica A. Juss.) and Chinaberry (Melia azedarach L.) seed oils as repellents against laboratory and field populations of some sandflies in Ethiopia. In the laboratory, concentrations of 2% and 5% neem oil in coconut oil tested against Phlebotomus orientalis (vector of visceral leishmaniasis) provided 96.28% (95% CI=95.60-96.97) protection up to a mean time of 7h and 20 min and 98.26% (95% CI=93.46-104. 07) protection up to 9h, respectively. Similarly, M. azedarach oil at 2% concentration produced 95.13% (95% CI=90.74-99.52) protection for the same duration (7h and 20 min), while the 5% oil gave 96.20 (95% CI=86.98-105.41) protection for 8h and 20 min against the same species with no significant difference in percentage protection between the two oils at 2% and 5% concentrations. In the field tests with only neem oil (A. indica) against field populations of P. orientalis and P. bergeroti, similar high level of repellencies were recorded with about the same duration of protection. Application of both neem and Chinaberry oils can be safe and low-cost means of personal protection against sandfly bites in endemic areas of Ethiopia, if the community is advised and encouraged to grow the plants abundantly.

From transcriptome to immunome: identification of DTH inducing proteins from a Phlebotomus ariasi salivary gland cDNA library.

Delayed-type hypersensitivity (DTH) response to arthropod vector salivary proteins is associated with protection against pathogen transmission. Massive cDNA sequencing, high-throughput DNA plasmid construction and DNA immunisation were used to identify twelve DTH inducing proteins isolated from a Phlebotomus ariasi salivary gland cDNA library. Additionally, nine P. ariasi DNA plasmids produced specific anti-saliva antibodies, four of these showed a Th1 immune response while the other two exhibited a Th2 profile as determined by IgG2a and IgG1 isotype switching, respectively. In order to validate the specificity of sand fly DNA plasmids, mice previously exposed to sand fly saliva were intradermally injected once with selected P. ariasi plasmids and a specific DTH response consisting of infiltration of mononuclear cells in varying proportions was observed at 24 and 48 h. This approach can help to identify DTH inducing proteins that may be related to host protection against vector-borne diseases or other disease agents where cellular immune response is protective.

[Evaluation of repellent and anti-feeding effect of garlic oil (Allium sativum) against the bite of phlebotomine sandflies Diptera: Psychodidae]. / Valutazione dell'effetto repellente ed anti-feeding dell'olio d'aglio (Allium sativum) nei confronti dei flebotomi (Diptera: Psychodidae).

The repellent and anti-feeding effect of garlic oil was evaluated in laboratory conditions against the bite of Phlebotomus papatasi females. The effectiveness was evaluated by two different laboratory procedures: (i) topical application of garlic oil on five human volunteers, using the "standard cage test", and (ii) feeding sandflies on artificial membranes treated with the compound. Garlic oil showed a significant protection by topical application on the skin of volunteers, being the protection 97% and 40%, respectively at 1% and 0.005% dilution. Garlic oil showed also an anti-feeding effect when tested on the artificial membrane feeding apparatus; the anti-feeding effect was dose dependent, being 100% at 1%. The results of the present study confirm previous observations on the repellent effect of garlic oil against haematophagous arthropods.

Laboratory testing of the insect repellent KBR 3023 against Phlebotomus duboscqi (Diptera: Psychodidae).

The relative efficacy of commercially available formulations of the new repellent KBR 3023 (Bayrepel, Bayer, Germany) was compared against Phlebotomus duboscqi. The results provided laboratory evidence of phlebotomine sandfly sensitivity.

Transmission blocking vaccine studies in leishmaniasis: II. Effect of immunisation using Leishmania major derived 63 kilodalton glycoprotein, lipophosphoglycan and whole parasite antigens on the course of L. major infection in BALB/c mice.

BACKGROUND: Safe, effective and inexpensive vaccines may be the most practical tool for control of any form of leishmaniasis. Leishmaniasis produces a state of pre-immunition which is the underlying mechanism for prolonged immunity to re-infection. Low doses of parasites has been shown to be able to induce protection in mice. It is not known, however, how immune sera from a susceptible host immunised with Leishmania-derived antigens when taken in by the sandfly affects the development and the subsequent transmission of the parasite to naive hosts. OBJECTIVE: To monitor the course of disease in BALB/c mice following challenge using L. major infected P. duboscqi which had previously fed on immunised mice. METHODS: BALB/c mice were immunised adequately with Leishmania major-derived antigens namely, crude whole parasite (WPA), recombinant 63 kilodalton glycoprotein (rgp63), lipophosphoglycan (LPG) and a cocktail composed of rgp63 plus LPG antigens. Laboratory reared Phlebotomus duboscqi sandflies, the natural vector for L. major were later allowed to feed on immunised animals, interrupted and allowed to continue feeding on infected animals for an equal amount of time until they became fully engorged. The sandflies were maintained on apples as a carbohydrate source in an insectary maintained at a temperature of 25 degrees C and 80% relative humidity. On the seventh day these sandflies were used to infect naive BALB/c mice and the course of infection followed for a period of at least three months. RESULTS: Mice infected using sandflies which had previously fed on WPA or rgp63-immunized mice showed disease exacerbation as the infection progressed, whereas those infected using sandflies which had previously fed on LPG-immunised mice had the least lesion sizes compared to control mice infected using sandflies which had fed on saline immunised mice (p < 0.05). CONCLUSIONS: Results from this study indicate that the course of L. major infection in BALB/c mice was dependent on the infective dose of parasites transmitted by the sandflies. Results from this study suggests that sub-infective doses of the parasite from sandflies previously fed on animals immunised with Leishmania-derived antigens needs to be evaluated for their potential in vaccine development against Leishmania infections.

Transmission blocking vaccine studies in leishmaniasis: I. Lipophosphoglycan is a promising transmission blocking vaccine molecule against cutaneous leishmaniasis.

BACKGROUND: New strategies for control of leishmaniasis is needed as chemotherapy using antimonial drugs is prolonged, expensive, associated with side effects and relapses. Vector control has limitations and a vaccine which may be the best approach is not available. OBJECTIVES: To assess the level of inhibition of promastigote development and gut morphology in infected Phlebotomus duboscqi sandflies fed on different groups of BALB/c mice immunised with rgp63, lipophosglycan (LPG) or their cocktail and whole parasite antigens prepared from L. major culture-derived promastigotes. METHODS: BALB/c mice were immunised adequately with Leishmania major-derived antigens namely, crude whole parasite (WPA), recombinant 63 kilodalton glycoprotein (rgp63), LPG and a cocktail composed of rgp63 plus LPG antigens. Laboratory reared Phlebotomus duboscqi sandflies, the natural vector for L. major were later allowed to feed on immunised animals, interrupted and allowed to continue feeding on infected animals for an equal amount of time until they became fully engorged. The sandflies were maintained on apples as a carbohydrate source in an insectary maintained at a temperature of 25 degrees C and 80% relative humidity. Some of the sandflies were dissected on days 2, 4 and 6 after feeding and observed using the light and the transmission electron microscopy for any changes in their gut morphology. The remaining sandflies were all dissected on the sixth day post-feeding and examined for procyclics, nectomonads, haptomonads and metacyclic promastigote forms of Leishmania. RESULTS: Sandflies which had previously fed on WPA, LPG plus rgp63 cocktail and LPG-immunised mice showed the lowest infection rates compared to control sandflies fed on saline immunised mice (p < 0.05). A significant number of procyclic promastigotes, the first developmental form of the parasite in culture as well as in the sandfly was observed in sandflies which fed on LPG-immunised mice (p < 0.05). The dominant parasite form in sandflies which fed on rgp63 or LPG-immunised mice was the nectomonad form but very few of the infective metacyclic forms (p < 0.05). Control sandflies fed on saline immunised or infected mice alone displayed a normal pattern of parasite development up to the metacyclic stage. Studies showed that two possible mechanisms through which immune sera from immunised mice may cause inhibition of parasite development is by exflagellation of nectomonad forms and degeneration of the sandfly midgut epithelium as revealed by light and electron microscopy studies respectively. CONCLUSIONS: This study has shown that immune-mediated transmission blocking may be applied to Leishmania infections. Based on observation of the procyclic promastigotes, the dominance of the nectomonad forms, low infectivity rates in sandflies fed on LPG-immunised mice, we concluded that LPG stands out to be a promising transmission blocking vaccine candidate in leishmaniasis.

Lectins and toxins in the plant diet of Phlebotomus papatasi (Diptera: Psychodidae) can kill Leishmania major promastigotes in the sandfly and in culture.

Leishmania major promastigotes are agglutinated and die in their vector, Phlebotomus papatasi, after the sandflies feed on some plants that are found in their natural habitat. In in-vitro assays, extracts of Ricinus communis (Euphorbiaceae), Capparis spinosa (Capparaceae), Prosopis farcta (Mimosaceae) and Tamarix nilotica (Tamaricaceae) agglutinated and killed the parasites. This activity could be inhibited by specific carbohydrates, indicating that it was the result of various lectins in the extracts. An extract of Solanum luteum (Solanaceae) lysed the promastigotes under similar conditions and this cytotoxicity was not abated by the sugars tested. High mortality of promastigotes occurred in infected flies after they ingested an extract of R. communis, even when the extract fed to the flies had been pre-mixed with glucose, a carbohydrate that inhibited the agglutination caused by such an extract in vitro. The results indicate that the lectins and toxins found in the vegetation in L. major foci may decrease the transmission of the parasite.

Avaliação da competência vetorial de Lutzomyia intermedia, s.lat. (Lutz & Neiva, 1912) para Leishmania (Viannia) braziliensis, Vianna, 1911 e suas implicações epidemiológicas / Assessment of vectorial competence of Lutzomyia intermedia, s.lat. (Lutz & Neiva, 1912) for Leishmania (Viannia) braziliensis, Vianna, 1911 and its epidemiological implications

Este estudo teve por objetivo pesquisar infecção natural em Lutzomyia intermedia, testar a suscetibilidade dessa espécie frente a duas estirpes de Leishmania (V.) braziliensis procedentes da região amazônia "M2903" e Vale do Ribeira "7312". Subseqüentemente, tentar transmiti-las à hamsters não infectados mediante picada de exemplares colonizados infectados e, macerados de exemplares silvestres infectados. Além disso, estabelecer uma colônia dessa espécie de flebotomíneo para suprir os experimentos com exemplares colonizados. Como resultados, não detecta flagelados nos exemplares pesquisados (n=5.448). Nos experimentos de suscetibilidade 64 (76 por cento) exemplares silvestres se infectaram com a estirpe "M2903" e 59 (72 por cento) com a estirpe "7312". Para os colonizados, 53 (67 por cento) e 62 (73 por cento) exemplares se infectaram com essas estirpes, respectivamente. Nos experimentos de transmissão via picada, 39 exemplares supostamente infectados com a estirpe "M2903" foram expostos à realimentação em hamsters não infectados. De 03 exemplares que se realimentaram, 02 estavam infectados. Para a estirpe "7312", dos 43 exemplares que foram expostos à realimentação, 02 exemplares realimentaram, sendo encontrado 01 infectado. em ambos experimentos, entretanto, não foram encontrados hamsters positivos para Leishmania após picada desses insetos. Nos experimentos de transmissão via macerados, 20 (57,1 por cento) hamsters desenvolveram lesões com a estirpe "M2903" e 22 (68,7 por cento) também o fizeram em relação à estirpe "7312". Conclui que as avaliação de caráter experimental mostraram que a espécie Lutzomyia intermedia foi suscetível a diferentes estirpes de Leishmania (V.) braziliensis, propiciando a multiplicação e/ou desenvolvimento desse agente infeccioso no seu trato digestivo (AU)

Recoverability of Rift Valley fever and sandfly fever Sicilian viruses from infected Phlebotomus papatasi (Diptera: Psychodidae) trapped in various oils.

We studied the effects of various oils used to trap sand flies on the recovery of virus from infected adult Phlebotomus papatasi. Both Rift Valley fever and sandfly fever Sicilian viruses were readily recovered from virus-inoculated specimens held at 26 degrees C on mineral, olive or castor oil-soaked sheets for up to 12 h. However, after 50 h on oil-soaked paper, significantly greater titers were recovered from sand flies trapped with mineral oil than from sand flies trapped with either of the other oils. This indicates that sand flies trapped on oil-soaked paper would be suitable for virus isolation attempts and that mineral oil had the least effect on virus recovery.

El papel del cafeto en la endemicidad de la leishmaniasis cutánea en Venezuela / The role of coffee-tree in the morbidity of cutaneous leishmaniasis in Venezuela

Se hace énfasis en la superposición de las áreas cafetaleras y las de endemicidad de las leishmaniasis cutáneas en la región de Los Andes de Venezuela. Se presentan evidencias sobre el papel de los frutos maduros de café como fuente de azúcares para los flebótomos y al mismo tiempo se demuestra la persistencia de promastigotos de Leishmania spp. hasta por cuarenta y ocho horas en el parénquima de tales frutos. Se discute la significación de estos hallazgos