RESUMO
Paraná state presents the fourth highest number of accumulated cases of hantavirus pulmonary syndrome in Brazil. To map the risk areas for hantavirus transmission we carried out a study based on rodent trapping and determined the anti-hantavirus seroprevalence in these animals and in the inhabitants of these localities. Overall seroprevalence in rodents and humans were 2.5% and 2.4%, respectively. Eighty-two percent of the seropositive rodents were genetically analyzed. Phylogenetic analyses revealed that hantaviruses from rodent samples cluster with Araucária (Juquitiba-like) or Jaborá hantavirus genotypes. The Jaborá strain was identified in Akodon serrensis and Akodon montensis, whereas the Araucária strain was detected in Oligoryzomys nigripes, Oxymycterus judex, A. montensis, and Akodon paranaensis, with the latter species being identified for the first time as a natural host. These findings expose the complex relationships between virus and reservoirs in Brazil, which could have an impact on hantavirus transmission dynamics in nature and human epidemiology.
Assuntos
Ecossistema , Síndrome Pulmonar por Hantavirus/veterinária , Síndrome Pulmonar por Hantavirus/virologia , Orthohantavírus/isolamento & purificação , Doenças dos Roedores/virologia , Adulto , Animais , Anticorpos Antivirais/sangue , Brasil/epidemiologia , Estudos Transversais , Genótipo , Orthohantavírus/genética , Síndrome Pulmonar por Hantavirus/epidemiologia , Síndrome Pulmonar por Hantavirus/genética , Humanos , Filogenia , RNA Viral/química , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Doenças dos Roedores/epidemiologia , Roedores , Estudos SoroepidemiológicosRESUMO
Here we report the hydrolytic behavior of recombinant YFV NS2B/NS3 protease against FRET substrates mimicking the prime and non-prime region of the natural polyprotein cleavage sites. While the P2-P'1 motif is the main factor associated with the catalytic efficiency of Dengue (DV) and West Nile Virus (WNV) protease, we show that the k(cat)/K(m) of YFV NS2B/NS3 varied by more than two orders of magnitude, despite the presence of the same motif in all natural substrates. The catalytic significance of this homogeneity - a unique feature among worldwide prominent flavivirus - was kinetically analyzed using FRET peptides containing all possible combinations of two and three basic amino acids in tandem, and Arg and Lys residues produced distinct effects on k(cat)/K(m). The parallel of our data with those obtained in vivo by Chambers et al. (1991) restrains the idea that these sites co-evolved with the NS2B/NS3 protease to promote highly efficient hydrolysis and supports the notion that secondary substrate interaction distant from cleavage sites are the main factor associated with the different hydrolytic rates on YFV NS2B-NS3pro natural substrates.
