The sublethal effects of the entomopathic fungus <i>Leptolegnia chapmanii</i> on some biological parameters of the dengue vector <i>Aedes aegypti</i>

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti.Centro de Estudios Parasitológicos y de VectoresInstituto de Botánica "Dr. Carlos Spegazzini

The sublethal effects of the entomopathic fungus <i>Leptolegnia chapmanii</i> on some biological parameters of the dengue vector <i>Aedes aegypti</i>

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti.Centro de Estudios Parasitológicos y de VectoresInstituto de Botánica "Dr. Carlos Spegazzini

The sublethal effects of the entomopathic fungus <i>Leptolegnia chapmanii</i> on some biological parameters of the dengue vector <i>Aedes aegypti</i>

The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti.Centro de Estudios Parasitológicos y de VectoresInstituto de Botánica "Dr. Carlos Spegazzini

Micología Forense

Hasta hace muy poco tiempo, el uso de la Micología como evidencia en casos criminales y su empleo como prueba ante la justicia estaban restringidos a casos relacionados con especies venenosas o psicotrópicas. Sin embargo, durante los últimos años se han registrado algunas situaciones en las cuales la presencia de los hongos ha sido tenida en cuenta como prueba válida ante la justicia. El término micología forense es relativamente nuevo y hace referencia al empleo de los hongos como evidencia para la resolución de casos con intervención judicial. El objetivo principal de esta rama de la biología forense es datar intervalos post-mortem y post-entierro a partir de la biota fúngica hallada en la superficie de un cuerpo o en el entorno relacionado a un entierro clandestino

Micología Forense

Nueva Línea de investigación en la Argentin

First record of <i>Aedes aegypti</i> (L.) (Diptera: Culicidae) infected by the parasite <i>Ascogregarina culicis</i> (Ross) (Apicomplexa: Lecudinidae) in Argentina

In a survey for parasites and pathogens of Aedes aegypti conducted in La Plata, Argentina, an aseptate gregarine was found parasitizing larvae, pupae and adults of this mosquito species. This gregarine species was identified as Ascogregarina culicis based on the morphology and size of gamonts, gametocysts and oocysts. It is the first record of gregarine infections in culicids from ArgentinaCentro de Estudios Parasitológicos y de VectoresConsejo Nacional de Investigaciones Científicas y TécnicasComisión de Investigaciones Científicas de la provincia de Buenos Aire

First record of <i>Aedes aegypti</i> (L.) (Diptera: Culicidae) infected by the parasite <i>Ascogregarina culicis</i> (Ross) (Apicomplexa: Lecudinidae) in Argentina

In a survey for parasites and pathogens of Aedes aegypti conducted in La Plata, Argentina, an aseptate gregarine was found parasitizing larvae, pupae and adults of this mosquito species. This gregarine species was identified as Ascogregarina culicis based on the morphology and size of gamonts, gametocysts and oocysts. It is the first record of gregarine infections in culicids from ArgentinaCentro de Estudios Parasitológicos y de VectoresConsejo Nacional de Investigaciones Científicas y TécnicasComisión de Investigaciones Científicas de la provincia de Buenos Aire

First record of <i>Aedes aegypti</i> (L.) (Diptera: Culicidae) infected by the parasite <i>Ascogregarina culicis</i> (Ross) (Apicomplexa: Lecudinidae) in Argentina

In a survey for parasites and pathogens of Aedes aegypti conducted in La Plata, Argentina, an aseptate gregarine was found parasitizing larvae, pupae and adults of this mosquito species. This gregarine species was identified as Ascogregarina culicis based on the morphology and size of gamonts, gametocysts and oocysts. It is the first record of gregarine infections in culicids from ArgentinaCentro de Estudios Parasitológicos y de VectoresConsejo Nacional de Investigaciones Científicas y TécnicasComisión de Investigaciones Científicas de la provincia de Buenos Aire

Isolation, characterization and evaluation of mosquitocidal activity of <i>Lysinibacillus</i> strains obtained from <i>Culex pipiens</i> larvae

Three strains—C107, C207, and C307—of spore-forming Gram-positive motile rod-shaped bacteria were isolated from dead larvae of Culex pipiens in La Plata city, Argentina. The three bacterial strains have different phenotypic and molecular characteristics. A comparative analysis of their 16S rRNA gene sequences and phylogenetic analysis demonstrated that isolates C107 and C207 were related to reference strains of Lysinibacillus sphaericus, while C307 was related to Bacillus licheniformis. The cytomorphology, biochemical characterization, and phylogenetic relatedness corroborated these respective group assignments. The isolated bacterial strain exhibited the same PCR amplified pattern for the binA, binB, and mtx genes as did the reference strains used. These bacterial strains presented different pathogenic actions among the following mosquito species tested: Culex pipiens, Aedes aegypti, Culex dolosus, Culex apicinus, Ochlerotatus albifasciatus, and Anopheles albitarsis. Only isolates C107 and C207 exhibited mosquitocidal activity. Culex pipiens was the species most susceptible to C107 (LC₅₀, 4 × 10⁴ spores/ml), while O. albifasciatus was most susceptible to C207 (LC₅₀, 3.4 × 10⁶ spores/ml).Facultad de Ciencias Naturales y MuseoCentro de Estudios Parasitológicos y de Vectore

Screening for a culture medium yielding optimal colony growth, zoospore yield and infectivity of different isolates of Leptolegnia chapmanii (Straminipila: Peronosporomycetes)

Leptolegnia chapmanii is an aquatic fungus that has demonstrated marked pathogenicity towards the larvae of a number of mosquito species with little or no effect on non-target insects. The aim of this work was to determine the best culture medium for colony growth, and production and infectivity of zoospores among different isolates of L. chapmanii. No significant differences (P >0.01) were observed for the media FORT(agar), PYG, YPSS, and PYGSF in terms of colony diameter of the different isolates evaluated. In these culture media, all L. chapmanii isolates had the highest growth (45 mm2) after 7 days. The nine isolates tested produced the greatest number of zoospores in FORT(agar) medium 3 (1 × 106 zoospores/ml). Medium YPSS exhibited significant differences (P <0.0001) compared to other culture media with respect to maintenance of virulence and infectivity of the isolates, producing 100% larval mortality after 48 h of inoculation. Thus, for the cultivation and maintenance of L. chapmanii isolates, the medium of choice among those tested is FORT(agar), as it is both inexpensive to prepare and ensures optimal colony development, extremely high zoospore production, and excellent maintenance of fungal infectivity.Centro de Estudios Parasitológicos y de Vectore