Mayaro virus and dengue virus 1 and 4 natural infection in culicids from Cuiabá, state of Mato Grosso, Brazil

This study aimed to verify the diversity of Culicidae species and their frequency of infection with flaviviruses and alphaviruses in Cuiabá, state of Mato Grosso, Brazil. Mosquitoes were captured with Nasci aspirators and hand net in 200 census tracts, identified alive at species level and pooled in one-20 (11,090 mosquitoes, 14 species). Female pools (n = 610) were subjected to multiplex seminested-reverse transcription-polymerase chain reaction (RT-PCR) for 11 flavivirus and five alphavirus. Positive pools were tested by single RT-PCR followed by nucleotide sequencing, by RT-PCR for E1 gene [Mayaro virus (MAYV)] and by inoculation in Vero cells (MAYV) or C6/36 cells (flaviviruses). One/171 Aedes aegypti was positive for dengue virus (DENV)-1, 12/403 Culex quinquefasciatus , and four/171 Ae. aegypti for MAYV, which was isolated from two pools containing two nonengorged females of Ae. aegypti and two of Cx. quinquefasciatus. DENV-4 was detected in 58/171 pools of Ae. aegytpi, 105/403 Cx. quinquefasciatus, two/five Psorophora sp., two/11 Psorophora varipes / Psorophora albigenu , one/one Sabethes chloropterus , two/five Culex bidens / Culex interfor , and one/one Aedes sp. DENV-4 was isolated from two pools containing three and 16 nonengorged Cx. quinquefasciatus females. Phylogenetic analysis revealed MAYV belongs to genotype L, clustering with human samples of the virus previously identified in the city. Cuiabá has biodiversity and ecosystem favourable for vector proliferation, representing a risk for arbovirus outbreaks.

Antiviral activity and mechanism of action of arbidol against Hantaan virus infection

Purpose: To investigate the activity and mechanism of action of arbidol against Hantaan virus (HTNV) activity by modulating inflammation via TLR-4 pathway. Methods: HUVEC cells infected with HTNV 76-118 were treated with serially diluted arbidol solutions at -2h (2 h before viral infection, pre-treatment mode), 0 h (at the same time as viral infection, simultaneous treatment mode) or 2 h (2 h after viral infection, post-treatment mode). The transcript levels of TLR4 were detected by semi-quantitative reverse transcription-PCR (RT-PCR) at 6, 12, 18, and 24 h later. The levels of iNOS and TNF-α were examined using enzyme-linked immunosorbent assay (ELISA). Results: Pre-treatment with arbidol, rather than simultaneous treatment or post-treatment, effectively inhibited up-regulation of cellular TLR4 expression (up to 40 ± 6.1 % inhibition) and activity of supernatant iNOS induced by HTNV infection(up to 44.1 ± 9.4 % inhibition), as well as in a LPSstimulated inflammatory endothelial cell. Arbidol decreased the elevated TNF-α levels induced by LPS stimulation. Conclusion: These results are the first evidence that arbidol modulates viral PRRs signaling and its consequential inflammatory cytokine/chemokine response during hantavirus infection.