ABSTRACT
The family Dicistroviridae comprises three genera and about twenty species of RNA virus, most of them with health or agricultural importance. The Triatoma virus (TrV) is the only entomopathogenic virus identified in triatomine bugs up to the present. TrV replicates within the intestinal epithelial cells, causing high mortality rate and delayed development of the molt of these bugs. TrV has been proposed as a biological control agent for vectors of Chagas disease. Viral particles were purified from feces of 1, 5 and 10 insects from an experimental colony of Triatoma infestans infected with TrV. Viral concentration and infectivity were corroborated using polyacrylamide gels and RT-PCR, respectively. In this work we report a method of viral purification that allows to reduce necessary reagents and time, using a very small amount of fecal matter.
La familia Dicistroviridae está compuesta por tres géneros y casi una veintena de especies de virus ARN, la mayoría de ellas de importancia sanitaria o agrícola. Triatoma virus (TrV) es el único virus entomopatógeno identificado en triatominos hasta el momento. El TrV se replica en las células del epitelio intestinal; ello provoca una alta tasa de mortalidad y retraso en el desarrollo de la muda del insecto. Se ha propuesto la utilización de TrV como agente de control biológico para vectores de la enfermedad de Chagas. Las partículas virales fueron purificadas a partir de materia fecal de 1, 5 y 10 insectos obtenidos de una colonia experimental infectada con TrV de Triatoma infestans y se corroboró su concentración viral e infectividad mediante geles de poliacrilamida y RT-PCR, respectivamente. En este trabajo se reporta un método de purificación viral que permite la reducción de los reactivos y del tiempo necesario para lograr dicha purificación, partiendo de una mínima cantidad de materia fecal.
Subject(s)
Animals , Triatoma , Dicistroviridae , Triatoma/microbiology , Chagas Disease , Feces/microbiology , Dicistroviridae/isolation & purification , Insect VectorsABSTRACT
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 Argentina.
Subject(s)
Animals , Aedes , Dengue , Diptera , Argentina/epidemiologyABSTRACT
We evaluated the potential of Mesocyclops annulatus as a control agent of Aedes aegypti in La Plata city (Argentina). Mosquito larval survivorship due to predation by these copepods was estimated at weekly intervals during the oviposition period of A. aegypti. Mean weekly A. aegypti larval survivorship in cylindrical plastic containers (12 cm height and 11 cm diameter) with copepods was significantly lower than in control containers. Furthermore, weekly larval survival was negatively correlated with M. annulatus adult density, and approximately 23 adult copepods/container would be a threshold density over which the weekly mosquito larval survivorship approached zero. The copepods were able to persist in all containers during approximately 100 days (in three of them until the end of the experiment: 155 days) without the resource represented by A. aegypti larvae. The predation and persistence observed suggest that M. annulatus is a potential control agent to be considered in biological control programs.
Subject(s)
Animals , Female , Aedes , Copepoda , Insect Vectors , Pest Control, Biological , Predatory Behavior , Argentina , Larva , SeasonsABSTRACT
In laboratory bioassays we tested the predatory capacity of the copepod Mesocyclops annulatus on Aedes aegypti and Culex pipiens larvae. A single adult female of M. annulatus caused 51.6 percent and 52.3 percent mortality of 50 first instar larvae of Ae. aegypti and Cx. pipiens respectively, in a 72 h test period. When alternative food was added to the containers, mortality rates declined to 16 percent and 10.3 percent for Ae. aegypti and Cx. pipiens respectively. When 50 first instar larvae of each of the two mosquito species tested were placed together with a single adult female of M. annulatus, mortality rates were 75.5 percent for Ae. aegypti larvae and 23.5 percent for Cx. pipiens larvae in a three day test period. Different density of adult females of M. annulatus ranged from 5 to 25 females produced mortality rates of Ae. aegypti first instar larvae from 50 percent to 100 percent respectively. When a single adult female of M. annulatus was exposed to an increasing number of first-instar Ae. aegypti larvae ranging from 10 to 100, 100 percent mortality was recorded from 1 to 25 larvae, then mortality declined to 30 percent with 100 larvae. The average larvae killed per 24 h period by a single copepod were 29