Browsing by Autor "Elsa Nieves"

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Actividad repelente de aceites esenciales contra las picaduras de Lutzomyia migonei (Diptera: Psychodidae)
(Vicerractoría Investigación, 2009) Elsa Nieves; Janett Fernández Méndez; José Lias; Maritza Rondón; Benito Briceño
Natural repellents from plant extracts have demonstrated good efficacy against bites of some insect species. The present study evaluated the repellent effect of essential oils extracted from 8 plants species against bites of Lutzomyia migonei, the Leishmania vector. The essential oils were extracted by steam destillation in Clevenger chamber, from the following plants: Hyptis suaveolens, Pimenta racemosa, Piper marginatum, Monticalia imbricatifolia, Pseudognaphalium caeruleocanum, Espeletia shultzii, Plecthranthus amboinicus and Cinnamomun zeylanicum. Repellency tests were performed under laboratory conditions by the human hand method in cage assays, using female colonies of L. migonei. The more effective oils were tested at variable concentrations on different volunteers. The protection percentage and time were calculated. The results showed what oils of P. caeruleocanum and C. zeylanicum were the most effective. Although P. amboinicus oil also had repellent effect showed an irritant effect. The oils P. marginatum, H. suaveolens and P. racemosa showed no repellent effect, while the rest of oil extracts showed significant repellency in variable degrees. P. caeruleocanum and C. zeylanicum oils provided the 95% protection against bites of L. migonei for 3 h. The P. caeruleocanum oil showed the greatest protection time, with a mean over 4h and 3h at concentrations of 50% and 10% respectively. The results suggest that the P. caeruleocanum oil could represent a potential natural repellent against Leishmania vectors.
Caloric content of the sand fly Lutzomyia ovallesi (Diptera: Psychodidae) vector of Leishmania
(2006) Pedro Noguera; Maritza Rondón; Elsa Nieves
Females of the sand fly Lutzomyia ovallesi (Ortiz) (Diptera: Psychodidae) were fed with blood from various species of vertebrates and analyzed to determine energy reserves under laboratory conditions. L. ovallesi specimens were allowed to artificially feed to satiation through chicken membranes on blood from horse, dog, cow, chicken, goat, pig or human. Caloric reserves were calculated spectrophotometrically after females were homogenized in a solution of sodium dichromate and sulfuric acid. The caloric content of L. ovallesi varied according to the type of vertebrate blood on which it had fed. The highest content (cal/insect) was found in females fed on human blood (0.33), followed in decreasing order by dog, pig, cow, chicken, goat and horse (0.26). Statistical analysis showed significant differences (P < 0.05) among sources. The results showed that human and dog blood meals were more nutritionally efficient. The most inefficient diet for L. ovallesi was horse blood manifested by its poor nutritional quality.
Impacto de Leishmania amazonensis y la Sangre de Ave en el Potencial Biológico y Fecundidad de Lutzomyia migonei y Lutzomyia ovallesi (Diptera: Psychodidae)
(Entomologistas do Brasil, 2011) Elsa Nieves; Jose Luis Oliveros; Maritza Rondón
En los flebótomos (Diptera: Psychodidae), la ingesta sanguínea es responsable de la inducción de varios procesos fisiológicos y es determinante en la transmisión de Leishmania Ross. El presente trabajo estudia la sangre de ave, de mamífero y mezclada con Leishmania amazonensis Lainson & Shaw sobre el potencial biológico de Lutzomyia migonei França y Lutzomyia ovallesi Ortiz. Se utilizaron hembras de ambas especies alimentadas artificialmente con sangre de hámster (Mesocricetus auratus Waterhouse) y de pollo (Gallus gallus Linnaeus), mezclada con L. amazonensis. Los grupos controles fueron hembras alimentadas sólo con sangre. Se determinó el grado de ingurgitación sanguínea, el tiempo de digestión sanguínea, el modelo de diuresis, el tiempo de oviposición, la sobrevivencia a la ovipostura y la fecundidad. L. migonei alimentadas con ambos tipos de sangre presentó mayor fecundidad que las hembras de L. ovallesi, la mayor fecundidad se registró con sangre de pollo. La presencia de Leishmania en la sangre de pollo o hámster disminuyó significativamente la masa sanguínea ingerida y redujo la sobrevivencia a la ovipostura en las hembras de L. migonei alimentadas con sangre de pollo y no con sangre de hámster. Sin embargo, no afectó la masa sanguínea ingerida, ni la sobrevivencia a la ovipostura de L. ovallesi. Mientras que la infección con L. amazonensis aumentó la cantidad de huevos retenidos y disminuyó el número de huevos puestos por L. migonei y por L. ovallesi en especial con sangre de pollo. Además, disminuyó el tiempo de digestión sanguínea en ambas especies alimentadas con sangre de pollo, pero no con la sangre de hámster. Aunque la sangre de pollo fue menos efectiva que la sangre de hámster sobre el potencial biológico de L. migonei y L. ovallesi, no se descarta a la sangre de pollo como una fuente sanguínea importante en el mantenimiento de las poblaciones de ambas especies en el peridomicilio. Impacto de Leishmania amazonensis e Sangue de Ave no potencial Biológico e fertilidade de Lutzomyia migonei e Lutzomyia ovallesi (Diptera: Psychodidae) Resumo. Nos flebotomíneos (Diptera: Psychodidae) o hábito pela hematofagia é responsável pela indução de vários processos fisiológicos também na transmissão de Leishmania Ross. O presente estudo compara o sangue de ave, de mamífero e com infecção por Leishmania amazonensis Lainson & Shaw sobre o potencial biológico de Lutzomyia migonei (França) e de Lutzomyia ovallesi Ortiz. Foram utilizadas fêmeas das duas espécies alimentadas artificialmente com sangue de hamster (Mesocricetus auratus Waterhouse) e frango (Gallus gallus Linnaeus), infectados com L. amazonensis. Os grupos controle foram alimentados somente com sangue, sem parasitas. Foram determinados o grau de repasto sanguíneo, o tempo de digestão, o padrão de diurese, o tempo de oviposição, a sobrevivencia a oviposição e a fecundidade. A espécie L. migonei quando alimentada com sangue de hamster e frango apresentaram maior fecundidade do que as fêmeas de L. ovallesi, a maior fecundidade foi com sangue de frango. A presença de Leishmania no sangue de frango ou sangue de hamster diminuiu significativamente o seu consumo, o que resultou na diminuição da sobrevida das fêmeas após a oviposição em L. migonei alimentados com sangue de frango e não com sangue de hamsters. Entretanto, não afetar a quantidade de sangue e a sobrevivência de oviposição de L. ovallesi. A infecção com L. amazonensis causo um aumento no número de ovos retidos e diminuiu o número de ovos postos por L. migonei e L. ovallesi, especialmente com sangue de frango e também reduz o tempo de digestão do sangue em ambas as espécies com sangue de frango, mas não com sangue de hamster. Embora o sangue de frango foi menos eficaz do que o sangue de hamster sobre o potencial biológico de L. migonei e L. ovallesi, não exclui o sangue de frango como uma fonte de sangue para a manutenção das populações de ambas as espécies nas casas.
Las proteínas salivales de los flebotominos en la transmisión de Leishmania y su impacto epidemiológico
(Universidad Internacional de La Rioja, 2013) Elsa Nieves; Mireya Sánchez; Maritza Rondón
The sandflies are haematophagous insects transmitting Leishmania, the causative agent of leishmaniasis, a disease that has a broad clinical spectrum in humans. This paper is a review on the saliva of sandflies in the transmission of Leishmania and the epidemiological impact. It first addresses the potential of the saliva of sandflies as a drug cocktail that is involved in the insect's biology, in the process of infection with Leishmania, their ability to be used as an epidemiological marker and protein source for a vaccine against leishmaniasis
Potencial parasiticida de Pimenta racemosa (Myrtales: Myrtaceae)
(Universidad Internacional de La Rioja, 2017) Elsa Nieves; Leidy Stefany Calles; Maritza Rondón; Billmary Z. Contreras Moreno; Bernardo Chataing
American trypanosomiasis, leishmaniasis and schistosomiasis are parasitic diseases that affect millions of people in the world and are a serious public health problem, mainly in Latin American. Current treatments are not satisfactory, hence the need for new compounds. The objective of this work was to determine the bioactive potential of the plant Pimenta racemosa (Myrtales: Myrtaceae) against parasites. Different bioassays were carried out with different parts of the Pimenta racemosa plant to determine the toxic activity on Artemia salina, on human erythrocytes and its parasiticidal effect against Leishmania amazonenesis, Trypanosoma cruzi and Schistosoma mansoni. Lethal concentrations were calculated and PERMANOVA analyzes were performed. The results showed that P. racemosa does not produce a toxic or cytotoxic effect. It also showed no effect against L. amazonensis promastigotes or against T. cruzi epimastigotes, presented high lethal concentrations being determined that are not within the range to be considered bioactive. While P. racemosa showed parasiticidal activity against the immature forms of S. mansoni, causing greater mortality and morphological alterations in the miracidia than in the cercariae and an attenuation effect on S. mansoni cercariae was evidenced. The parts of P. racemosa fine branches presented the lowest LC50 of 0.10 mg/ml (0.08-0.14 mg/ml). Data are provided on the bioactivity of P. racemosa, no biological activity was evidenced against L. amazonensis and T. cruzi. However, P. racemosa presented a low cytotoxicity, with no toxic effect and biocidal activity against the immature forms of S. mansoni. Therefore, it is suggested to deepen the studies to potentiate its antiparasitic secondary metabolites against S. mansoni.