Hymenoptera stings in Brazil: a neglected health threat in Amazonas State

<div><p>Abstract INTRODUCTION: Hymenoptera injuries are commonly caused by stinging insects. In Amazonas state, Brazil, there is no information regarding distribution, profile, and systemic manifestations associated with Hymenoptera injuries. METHODS: This study aimed to identify risk factors for systemic manifestation using the Brazilian Notifiable Diseases Surveillance System (2007 to 2015). RESULTS: Half of Hymenoptera injuries were caused by bee stings. Hymenoptera injuries were concentrated in Manaus, and 13.36% of cases displayed systemic signs. Delayed medical assistance (4 to 12 hours) presented four times more risk for systemic manifestations. CONCLUSIONS: Simple clinical observations and history of injury are critical information for prognostic improvement.</p></div

Viral immunogenicity determines epidemiological fitness in a cohort of DENV-1 infection in Brazil

<div><p>The dynamics of dengue virus (DENV) circulation depends on serotype, genotype and lineage replacement and turnover. In São José do Rio Preto, Brazil, we observed that the L6 lineage of DENV-1 (genotype V) remained the dominant circulating lineage even after the introduction of the L1 lineage. We investigated viral fitness and immunogenicity of the L1 and L6 lineages and which factors interfered with the dynamics of DENV epidemics. The results showed a more efficient replicative fitness of L1 over L6 in mosquitoes and in human and non-human primate cell lines. Infections by the L6 lineage were associated with reduced antigenicity, weak B and T cell stimulation and weak host immune system interactions, which were associated with higher viremia. Our data, therefore, demonstrate that reduced viral immunogenicity and consequent greater viremia determined the increased epidemiological fitness of DENV-1 L6 lineage in São José do Rio Preto.</p></div

Evolutionary relationship between DENV-1 isolates and co-circulation of the two lineages from SJRP.

<p>(A) Phylogenetic tree of DENV-1 after Bayesian inference based on envelope nucleotide sequences with aa substitutions, characterizing the L1 and L6 lineages from SJRP, which are shown in blue and red, respectively. (B) Comparison of amino acid substitutions between the representative complete genome sequences of L1 and L6 lineages from SJRP (287/2011 and 484/2012, respectively). (C) Circulation of DENV-1 lineages (L1 and L6) in SJRP from 2008 to 2015 based on sequencing and genotyping data.</p

Replicative fitness in mosquitoes under selective pressure of DENV-1 lineages.

<p>(A and B) Viral cDNA copy number of L1 or L6 viruses in PPCampos. (A) and Dom Pedro (B). (C and D) Proportion of the infection rate (IR), disseminated infection rate (DIR) and vector competence (VC) of L1 or L6 viruses in PPCampos (C) and Dom Pedro (D). (E) Coinfection of L1 and L6 isolates in Aag-2 cells (MOI = 0.1) (Student’s T test).</p

Replicative fitness in cell culture and cross-reactive immunity of DENV-1 lineages.

<p>(A) Growth curves of L1 or L6 isolates infected at an MOI of 0.1 in mosquito (C6/36 and Aag-2), human (HepG2) and non-human primate (Vero E6 and LLC-MK2) cell lines (<i>P</i> ≤ 0.05, Student’s T test). (B) Proportion of L1 or L6 DENV-1 cases classified as primary (negative IgG) or secondary (positive IgG) DENV infections (Fisher’s exact test).</p

sfRNA and expression of type I interferon antiviral responses by DENV-1 lineages.

<p>(A) Ratio of sfRNA:gRNA in HepG2 cells infected with L1 or L6 viruses at an MOI of 1.0 (Student’s T test). (B) Quantification of IFN-α1/13 production in supernatants of HepG2 cells by an ELISA (Chi-squared test). (C) Viral cDNA copy number of DENV-2, L1 or L6 viruses in HBMECs (before or after treatment with IFN-β) using real-time PCR. (D) IFN-induced luciferase activity in HBMECs that were mock-treated or infected with DENV-2, L1 or L6 DENV-1 in the presence or absence of IFN-β (Student’s T test). (E) Quantification of IFN-α2 production in negative controls and L1 or L6 DENV-1-infected patients using the Luminex assay (Mann-Whitney test).</p

Proposed model for L6 lineage (red) dominant circulation without L1 lineage replacement (blue) in the SJRP population, with the main differences found between the two DENV-1 lineages.

<p>Proposed model for L6 lineage (red) dominant circulation without L1 lineage replacement (blue) in the SJRP population, with the main differences found between the two DENV-1 lineages.</p

Quantification of cytokines, chemokines, adhesion molecules and growth factors showing significant differences in L1 or L6 DENV-1-infected patients.

<p>(A) IL-1RA. (B) IL-12p40. (C) IL-7. (D) IL-17a. (E) IL-13. (F) EGF. (G) VEGF. (H) CCL11. (Mann-Whitney test). See also <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0006525#pntd.0006525.s003" target="_blank">S3 Fig</a>.</p

Viral load quantification of DENV-1-infected patients using real-time PCR.

<p>Viral load quantification of DENV-1-infected patients using real-time PCR.</p