María del Carmen Marquetti

Aedes aegypti larval indices and risk for dengue epidemics.

Entomologic indices can identify areas at high risk for disease transmission.

Factores ecológicos asociados con la presencia de larvas de Aedes aegypti en zonas de alta infestación del municipio Playa, Ciudad de La Habana, Cuba

OBJETIVOS: Identificar los factores ecologicos locales que pudieron incidir en la mayor infestacion vectorial con Aedes aegypti observada en cuatro areas de salud urbanas de Ciudad de La Habana, Cuba, asi como los tipos de depositos con mayor numero de larvas. METODOS: Estudio descriptivo en cuatro areas de salud (Docente, 28 de Enero, 26 de Julio y 1.° de Enero) del municipio Playa, Ciudad de La Habana, Cuba, seleccionadas por la presencia reiterada del vector del dengue en el ano 2003. Entre abril de 2004 y marzo de 2005 se inspeccionaron todos los locales de las manzanas seleccionadas. Se caracterizaron los depositos existentes con agua (tipo, cantidad y ubicacion) y los factores ecologicos observados (existencia de patio y de sombra, forma en que estaban tapados los tanques, presencia de materia organica en ellos e higiene de la vivienda). Se contaron las larvas y pupas de mosquitos de cada deposito mediante filtracion. La identificacion taxonomica de las pupas se realizo con microscopio estereoscopico. RESULTADOS: Los depositos en que se encontraron larvas y pupas de A. aegypti con mayor frecuencia en todas las areas fueron los tanques bajos y los pequenos depositos artificiales. En tres de las areas estudiadas la mayor cantidad de pupas se encontro en los tanques bajos (88,6%, 100% y 56,6%), de los cuales 90,9% se encontraban destapados o tapados solo parcialmente, mientras que en el area restante los pequenos depositos artificiales fueron los mas frecuentes (85,7%). Se encontro correlacion entre el numero de depositos infestados en las viviendas con la presencia de patio (ji2 = 29,59; P = 0,0001), de sombra parcial (ji2 = 4,108; P = 0,0001), de vegetacion (ji2 = 43,59; P = 0,0001) y de arboles (ji2 = 101,459; P = 0,0001), asi como con la mala higiene (c² = 53,76; P = 0,0001). CONCLUSION: Los depositos artificiales, especialmente los tanques bajos y los recipientes pequenos, son las criaderos mas frecuentes de A. aegypti, por lo que constituyen un factor de riesgo de infestacion con ese vector. Los tanques destapados con materia organica y situados a la sombra y en el exterior fueron los mas peligrosos en ese sentido.

Effects of three organophosphorus insecticides in the reproductive potential of Culex quinquefasciatus

A Culex quinquefasciatus Say 1823 strain with resistant genes to organophosphates was tested in the laboratory to know the reproductive potential after exposure, as larvae, at the LC30 and LC70 (mg/l) of three organophosphorus insecticides: malathion, chlorpyrifos and methyl-pirimiphos. Data showed that fecundity was decreased significantly by malathion at LC30 = 0.0025 and LC70 = 0.0075, whereas fertility has a no significant decrement by chlorpyrifos and methyl-pirimiphos at the LC70 (0.000016, 0.00043). The sexual index was affected by chlorpyrifos and methyl-pirimiphos showing a greater number of adult females.

Essential Plant Oils and Insecticidal Activity in Culex quinquefasciatus

Plants have great importance for man because they are one of their sources of food, they provide us through the process of photosynthesis the oxygen we breathe and are essential to maintain the ecological balance (Corbino, 2000). Essential oils are volatile, usually distillable liquid fractions responsible for the aroma of the plant. The vast majority of them are pleasant smell and its metabolic and evolutionary significance lies in the role they play as attractor of pollinating agents (for its pleasant aroma), constitute elements of defense against the attack of parasites, herbivorous animals and insects, allow the adaptation of the plant when water is scarce and are part of the substances in reserve as the giver of H+ in the processes of electron. The organoleptic characteristics of the essential oils may be given by major components, although in other cases they are substances present in tiny quantities (traces) which define the taste, smell, or therapeutic properties (Scholes, 1995; Worwood, 1992). These natural substances are known as secondary metabolites, name which refers to substances that are not involved in the basic mechanisms of life of the plant but that comply with specific functions. (Corbino, 2000). They tend to accumulate in large amounts without negative effects and represent a problem in the cell or on the plant. These metabolites have the property to form glycosides and are found soluble in the plant. For many years these metabolites were regarded as final products of metabolic processes without specific function or directly as a waste of plant products (Lopez, 2008). The study of these substances was initiated by organic chemists of the 19th century and early 20th century who were interested in these substances because of its importance in the medical industry, the manufacture of flavoring, etc. In fact, the study of the secondary metabolites stimulated the development of separating techniques, and spectroscopy for determining their structure and synthesis which constituted the basis of the contemporary organic chemistry (Lopez, 2008). They can be found in different parts of the plant: leaves (wormwood, basil, buchu, cidron, eucalyptus, mint, lemongrass, marjoram, mint, patchouli, quenopod, rosemary, Sage, lemon balm, etc.), in the roots (angelic, asaro, saffron, calamus, turmeric, galanga, ginger, sandalwood, Sasafras, Valerian, vetiver, etc.), in the pericarp of the fruit (lemon, Tangerine, Orange, etc.), seeds (anise, cardamom, dill, fennel, cumin, etc.), in the stem (cinnamon, caparrapi, etc.), flowers (arnica, lavender, chamomile, pyrethrum, thyme, clove scent, rose,