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PLoS One ; 16(1): e0244937, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33406122


BACKGROUND: The impact of SARS-CoV-2 in regions endemic for both Dengue and Chikungunya is still not fully understood. Considering that symptoms/clinical features displayed during Dengue, Chikungunya and SARS-CoV-2 acute infections are similar, undiagnosed cases of SARS-CoV-2 in co-endemic areas may be more prevalent than expected. This study was conducted to assess the prevalence of covert cases of SARS-CoV-2 among samples from patients with clinical symptoms compatible with either Dengue or Chikungunya viral infection in the state of Espírito Santo, Brazil. METHODS: Presence of immunoglobulin G (IgG) antibody specific to SARS-CoV-2 nucleoprotein was detected using a chemiluminescent microparticle immunoassay in samples from 7,370 patients, without previous history of COVID-19 diagnosis, suspected of having either Dengue (n = 1,700) or Chikungunya (n = 7,349) from December 1st, 2019 to June 30th, 2020. FINDINGS: Covert cases of SARS-CoV-2 were detected in 210 (2.85%) out of the 7,370 serum samples tested. The earliest undiagnosed missed case of COVID-19 dated back to a sample collected on December 18, 2019, also positive for Dengue Virus. Cross-reactivity with either Dengue virus or other common coronaviruses were not observed. INTERPRETATION: Our findings demonstrate that concomitant Dengue or Chikungunya outbreaks may difficult the diagnosis of SARS-CoV-2 infections. To our knowledge, this is the first study to demonstrate, with a robust sample size (n = 7,370) and using highly specific and sensitive chemiluminescent microparticle immunoassay method, that covert SARS-CoV-2 infections are more frequent than previously expected in Dengue and Chikungunya hyperendemic regions. Moreover, our results suggest that SAR-CoV-2 cases were occurring prior to February, 2020, and that these undiagnosed missed cases may have contributed to the fast expansion of SARS-CoV-2 outbreak in Brazil. Data presented here demonstrate that in arboviral endemic regions, SARS-CoV-2 infection must be always considered, regardless of the existence of a previous positive diagnosis for Dengue or Chikungunya.

/epidemiologia , Febre de Chikungunya/epidemiologia , Dengue/epidemiologia , Adulto , Anticorpos Antivirais/sangue , Brasil/epidemiologia , Vírus Chikungunya/patogenicidade , Coinfecção/epidemiologia , Vírus da Dengue/patogenicidade , Erros de Diagnóstico/tendências , Surtos de Doenças , Feminino , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Prevalência , /patogenicidade
Microbes Infect ; 21(7): 328-335, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30817996


The use of adjuvants in vaccine formulations is a well-established practice to improve immunogenicity and protective immunity against diseases. Previously, we have demonstrated the feasibility of intranasal vaccination with the antigen of killed Leishmania amazonensis promastigotes (LaAg) against experimental leishmaniasis. In this work, we sought to optimize the immunogenic effect and protective immunity against murine visceral leishmaniasis conferred by intranasal delivery of LaAg in combination with a synthetic TLR1/TLR2 agonist (Pam3CSK4). Intranasal vaccination with LaAg/PAM did not show toxicity or adverse effects, induced the increase of delayed-type hypersensitivity response and the production of inflammatory cytokines after parasite antigen recall. However, mice vaccinated with LaAg/PAM and challenged with Leishmania infantum presented significant reduction of parasite burden in both liver and spleen, similar to those vaccinated with LaAg. Although LaAg/PAM intranasal vaccination had induced higher frequencies of specific CD4+ and CD8+ T cells and increased levels of IgG2a antibody isotype in serum, both LaAg and LaAg/PAM groups presented similar levels of IL-4 and IFN-y and decreased production of IL-10 when compared to controls. Our results provide the first evidence of the feasibility of intranasal immunization with antigens of killed Leishmania in association with a TLR agonist, which may be explored for developing an effective and alternative strategy for vaccination against visceral leishmaniasis.

Antígenos de Protozoários/imunologia , Leishmania/imunologia , Vacinas contra Leishmaniose/imunologia , Leishmaniose Visceral/imunologia , Lipopeptídeos/imunologia , Adjuvantes Imunológicos/administração & dosagem , Administração Intranasal , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/administração & dosagem , Citocinas/sangue , Feminino , Vacinas contra Leishmaniose/administração & dosagem , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/prevenção & controle , Lipopeptídeos/administração & dosagem , Fígado/metabolismo , Fígado/parasitologia , Linfócitos/imunologia , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Baço/metabolismo , Baço/parasitologia , Vacinação
Parasitol Res ; 116(3): 1071-1074, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28083657


An increased number of regulatory T (Treg) cells has been reported in patients with HTLV-1 and Strongyloides stercoralis co-infection, suggesting the contribution of these cells to worm survival. As Strongyloides infections have been found to be highly prevalent in chronic alcoholics, we investigated the effect of abusive ethanol ingestion on the induction of Treg cells in alcoholic patients with Strongyloides infection. Treg cells were assessed by flow cytometry in the peripheral blood of 12 healthy non-alcoholic (control) and 14 alcoholic patients (alcoholic) without Strongyloides infection and five non-alcoholics (controlSs) and five chronic alcoholics (alcoholSs) with Strongyloides infection. The results showed significantly higher frequencies of Treg cells in the alcoholic, controlSs and alcoholSs group patients than in the control group patients. However, the frequencies of Treg cells did not differ between the alcoholSs and controlSs groups. In conclusion, our results demonstrate that ethanol consumption induced an increase in the number of circulating Treg cells in chronic alcoholics in this study but was unable to potentiate the induction of these cells in alcoholics with Strongyloides infection.

Alcoolismo/sangue , Strongyloides stercoralis/fisiologia , Estrongiloidíase/sangue , Linfócitos T Reguladores/citologia , Adulto , Alcoolismo/imunologia , Alcoolismo/parasitologia , Animais , Feminino , Citometria de Fluxo , Humanos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Estrongiloidíase/imunologia , Estrongiloidíase/parasitologia , Linfócitos T Reguladores/imunologia