RESUMEN
Vertical transmission to progeny ensures the maintenance of arboviruses in their natural vectors. This mechanism is largely reported for dengue virus (DENV) and yellow fever virus (YFV). Few studies have addressed this mechanism for Zika virus (ZIKV), Mayaro virus (MAYV) and other arboviruses. The present study investigated the natural infection rate by arboviruses in 4490 Aedes (Stegomyia) aegypti and 296 Aedes (Stegomyia) albopictus (Diptera: Culicidae) reared from eggs collected with ovitraps in Cuiabá, Mato Grosso State, from February to July, 2017. After viral RNA extraction and reverse transcriptase-polymerase chain reaction protocols for 10 flaviviruses and five alphaviruses, nucleotide sequencing and three passages in C6/36 cells, eight pools of Ae. aegypti positive for DENV-4 genotype II, seven for ZIKV Asian genotype and two for MAYV genotype L were found. In addition, two Ae. albopictus pools were positive for DENV-4 genotype II and two were positive for ZIKV Asian genotype. Infection was confirmed by viral isolation in all positive pools for DENV-4 and for MAYV and in eight of nine for ZIKV. This mechanism may contribute to the spread of arboviruses during epidemics and also to their maintenance in natural vectors during interepidemic periods.
Asunto(s)
Aedes/virología , Alphavirus/fisiología , Virus del Dengue/fisiología , Mosquitos Vectores/virología , Virus Zika/fisiología , Animales , Brasil , Femenino , MasculinoRESUMEN
L-Arginine (ARG) is the precursor of the nitric oxide (NO) synthesis. NO-mediated signaling seems to be involved in the phenomenon of cortical spreading depression (CSD). Here, well-nourished and malnourished rats were treated, by gavage, with 150, 300 or 450 mg/kg/day of L-arginine from postnatal days 7-28, and CSD propagation was analyzed at 30-40 days. Compared to non-treated ('naïve') and water-treated controls, ARG-treated rats dose-dependently displayed higher CSD-velocities (P<0.05). In the malnourished rats, only the highest ARG-dose (450 mg/kg/day) increased CSD velocities. The mean +/- SD CSD-velocities (in mm/min) were: for well-nourished rats, 3.77 +/- 0.15, 3.78 +/- 0.23, 4.03 +/- 0.16, 4.36 +/- 0.19 and 4.41 +/- 0.26, in the naïve-, water-controls, 150, 300 and 450 mg/kg/day ARG-groups, respectively; for the same conditions in the malnourished rats, the velocities were 4.18 +/- 0.13, 4.22 +/- 0.09, 4.24 +/- 0.10, 4.27 +/- 0.21 and 4.64 +/- 0.22, respectively. Results demonstrate a dose- and nutrition-dependent CSD-facilitation by L-arginine administered during brain development. It is suggested that this effect is due to the modulation of nitric oxide synthesis.