Evaluation of humoral immune response after yellow fever infection: an observational study on patients from the 2017-2018 sylvatic outbreak in Brazil.

Between 2016 and 2018, Brazil experienced major sylvatic yellow fever (YF) outbreaks that caused hundreds of casualties, with Minas Gerais (MG) being the most affected state. These outbreaks provided a unique opportunity to assess the immune response triggered by the wild-type (WT) yellow fever virus (YFV) in humans. The plaque reduction neutralization test (PRNT) is currently the standard method to assess the humoral immune response to YFV by measuring neutralizing antibodies (nAbs). The present study aimed to evaluate the humoral immune response of patients from the 2017-2018 sylvatic YF outbreak in MG with different disease outcomes by using PRNTs with a WT YFV strain, isolated from the 2017-2018 outbreak, and a vaccine YFV strain. Samples from naturally infected YF patients were tested, in comparison with healthy vaccinees. Results showed that both groups presented different levels of nAb against the WT and vaccine strains, and the levels of neutralization against the strains varied homotypically and heterotypically. Results based on the geometric mean titers (GMTs) suggest that the humoral immune response after a natural infection of YFV can reach higher levels than that induced by vaccination (GMT of patients against WT YFV compared to GMT of vaccinees, P < 0.0001). These findings suggest that the humoral immune responses triggered by the vaccine and WT strains of YFV are different, possibly due to genetic and antigenic differences between these viruses. Therefore, current means of assessing the immune response in naturally infected YF individuals and immunological surveillance methods in areas with intense viral circulation may need to be updated.IMPORTANCEYellow fever is a deadly febrile disease caused by the YFV. Despite the existence of effective vaccines, this disease still represents a public health concern worldwide. Much is known about the immune response against the vaccine strains of the YFV, but recent studies have shown that it differs from that induced by WT strains. The extent of this difference and the mechanisms behind it are still unclear. Thus, studies aimed to better understand the immune response against this virus are relevant and necessary. The present study evaluated levels of neutralizing antibodies of yellow fever patients from recent outbreaks in Brazil, in comparison with healthy vaccinees, using plaque reduction neutralization tests with WT and vaccine YFV strains. Results showed that the humoral immune response in naturally infected patients was higher than that induced by vaccination, thus providing new insights into the immune response triggered against these viruses.

Serum soluble mediators as prognostic biomarkers for morbidity, disease outcome, and late-relapsing hepatitis in yellow fever patients.

This study described a soluble mediator storm in acute Yellow Fever/YF infection along the kinetics timeline towards convalescent disease. The analyses of the YF Viral RNAnemia, chemokines, cytokines, and growth factors were performed in YF patients at acute/(D1-15) and convalescent/(D16-315) phases. Patients with acute YF infection displayed a trimodal viremia profile spreading along D3, D6, and D8-14. A massive storm of mediators was observed in acute YF. Higher levels of mediators were observed in YF with higher morbidity scores, patients under intensive care, and those progressing to death than in YF patients who progress to late-relapsing hepatitis/L-Hep. A unimodal peak of biomarkers around D4-6 with a progressive decrease towards D181-315 was observed in non-L-Hep patients, while a bimodal pattern with a second peak around D61-90 was associated with L-Hep. This study provided a comprehensive landscape of evidence that distinct immune responses drive pathogenesis, disease progression, and L-Hep in YF patients.

Wild-type Yellow fever virus in cerebrospinal fluid from fatal cases in Brazil, 2018.

Yellow fever virus (YFV) is the causative agent of yellow fever (YF), a hemorrhagic and viscerotropic acute disease. Severe YF has been described in approximately 15-25% of YF patients, with 20-50% of severe YF cases being fatal. Here we analyzed cerebrospinal fluid (CSF) samples collected during the YF outbreak in Brazil in 2018, aiming to investigate CNS neuroinvasion in fatal YFV cases. YFV RNA was screened by RT-qPCR targeting the 3'UTR region of the YFV genome in CSF. CSF samples were tested for the presence of anti-YFV IgM and neutralizing antibodies, coupled with routine laboratory examinations. Among the 13 patients studied, we detected anti-YFV IgM in CSF from eight patients and YFV RNA in CSF from five patients. YFV RNA genomic load in CSF samples ranged from 1.75×103 to 5.42×103 RNA copies/mL. We genotyped YFV from three CSF samples that grouped with other YFV samples from the 2018 outbreak in Brazil within the South-American I genotype. Even though descriptions of neurologic manifestations due to wild type YFV (WT-YFV) infection are rare, since the last YF outbreak in Brazil in 2017-2018, a few studies have demonstrated WT-YFV RNA in CSF samples from YF fatal cases. Serological tests indicated the presence of IgM and neutralizing antibodies against YFV in CSF samples from two patients. Although the presence of viral RNA, IgM and neutralizing antibodies in CSF samples could indicate neuroinvasiveness, further studies are needed to better elucidate the role of YFV neuroinvasion and possible impacts in disease pathogenesis.

The ongoing COVID-19 epidemic in Minas Gerais, Brazil: insights from epidemiological data and SARS-CoV-2 whole genome sequencing.

The recent emergence of a coronavirus (SARS-CoV-2), first identified in the Chinese city of Wuhan in December 2019, has had major public health and economic consequences. Although 61,888 confirmed cases were reported in Brazil by 28 April 2020, little is known about the SARS-CoV-2 epidemic in this country. To better understand the recent epidemic in the second most populous state in southeast Brazil - Minas Gerais (MG) - we sequenced 40 complete SARS-CoV-2 genomes from MG cases and examined epidemiological data from three Brazilian states. Both the genome analyses and the geographical distribution of reported cases indicate for multiple independent introductions into MG. Epidemiological estimates of the reproductive number (R) using different data sources and theoretical assumptions suggest the potential for sustained virus transmission despite a reduction in R from the first reported case to the end of April 2020. The estimated date of SARS-CoV-2 introduction into Brazil was consistent with epidemiological data from the first case of a returned traveller from Lombardy, Italy. These findings highlight the nature of the COVID-19 epidemic in MG and reinforce the need for real-time and continued genomic surveillance strategies to better understand and prepare for the epidemic spread of emerging viral pathogens..

Mucosal leishmaniasis: the experience of a Brazilian referral center.

INTRODUCTION: Pentavalent antimonials (Sbv) are the most commonly used drugs for the treatment of mucosal leishmaniasis (ML), despite their high toxicity and only moderate efficacy. The aim of this study was to report therapeutic responses with different available options for ML. METHODS: This study was based on a review of clinical records of 35 patients (24 men and 11 women) treated between 2009 and 2015. RESULTS: The median age of patients was 63 years, and the median duration of the disease was 24 months. Seventeen patients received Sbv, while nine patients were treated with liposomal amphotericin B (AmB), and another nine patients were treated with fluconazole. Patients treated with AmB received a total median accumulated dose of 2550mg. The mean duration of azole use was 120 days, and the daily dose ranged from 450 to 900mg. At the three-month follow-up visit, the cure rate was 35%, 67%, and 22% for Sbv, AmB, and azole groups, respectively. At the six-month follow-up visit, the cure rates for Sbv, AmB, and azole groups were 71%, 78%, and 33%, respectively. CONCLUSIONS: There is a scarcity of effective ML treatment alternatives, and based on our observations, fluconazole is not a valid treatment option.

Meglumine antimoniate intralesional infiltration for localised cutaneous leishmaniasis: a single arm, open label, phase II clinical trial.

BACKGROUND: Cutaneous leishmaniasis (CL) is a world-wide health problem which currently lacks effective, affordable and easy to use therapy. Recently, the meglumine antimoniate (MA) intralesional infiltration was included among the acceptable therapies for New World leishmaniasis. While this approach is attractive, there is currently little evidence to support its use in Americas. OBJECTIVES: The aim of this study was to provide information about effectiveness and safety of a standardised MA intralesional infiltration technique for the treatment of CL. METHODS: It is a single-arm phase II clinical trial conducted at a Brazilian referral centre. CL cases with parasitological confirmation presenting a maximum of three CL-compatible skin lesions were treated with weekly MA intralesional infiltration by using a validated technique, up to a maximum of eight infiltrations. RESULTS: A total of 53 patients (62 lesions) were included. Overall, patients received a median of seven infiltrations (IQR25-75% 5-8) over a median treatment period of 43 days (IQR25-75% 28-52 days). The definitive cure rate at D180 was 87% (95% CI:77-96%). The majority of adverse events were local, with mild or moderate intensity. Bacterial secondary infection of the lesion site was observed in 13% of the treated patients, beside two intensity-three adverse events (hypersensitivity reactions).

Persistence of Yellow fever virus outside the Amazon Basin, causing epidemics in Southeast Brazil, from 2016 to 2018.

BACKGROUND: Yellow fever (YF) is endemic in the Brazilian Amazon Basin, and sporadic outbreaks take place outside the endemic area in Brazil. Since 2016, YF epidemics have been occurring in Southeast Brazil, with more than 1,900 human cases and more than 1,600 epizooties of non-human primates (NHPs) reported until April 2018. Previous studies have demonstrated that Yellow fever virus (YFV) causing outbreaks in 2017 formed a monophyletic group. METHODOLOGY/PRINCIPAL FINDINGS: Aiming to decipher the origin of the YFV responsible for the recent epidemics, we obtained nucleotide sequences of YFV detected in humans (n = 6) and NHPs (n = 10) from Minas Gerais state during 2017-2018. Next, we performed evolutionary analyses and discussed the results in the light of epidemiological records (official numbers of YFV cases at each Brazilian Federative unit, reported by the Brazilian Ministry of Health). Nucleotide sequences of YFV from Southeast Brazil from 2016 to 2018 were highly conserved and formed a monophyletic lineage (BR-YFV_2016/18) within the genotype South America I. Different clusters were observed within lineage BR-YFV_2016/18, one containing the majority of isolates (from humans and NHPs), indicating the sylvatic transmission of YFV. We also detected a cluster characterized by two synapomorphies (amino acid substitutions) that contained YFV only associated with NHP what should be further investigated. The topology of lineage BR-YFV_2016/18 was congruent with epidemiological and temporal patterns of the ongoing epidemic. YFV isolates detected in 2016, in São Paulo state were located in the most basal position of the lineage, followed by the isolates from Minas Gerais and Espírito Santo obtained in 2017 and 2018. The most recent common ancestor of the lineage BR-YFV_2016/18 dated to 2015 (95% credible intervals = 2014-2016), in a period that was coincident with the reemergence of YFV in the Midwest region of Brazil. CONCLUSIONS: The results demonstrated a single introduction of YFV in the Southeast region and the silent viral circulation before the onset of the outbreaks in 2016. Evolutionary analyses combined with epidemiological records supported the idea that BR-YFV_2016/18 was probably introduced from the Midwest into the Southeast region, possibly in São Paulo state. The persistence of YFV in the Southeast region, causing epidemics from 2016 to 2018, suggests that this region presents suitable ecological and climatic conditions for YFV maintenance during the epidemic and interepidemic seasons. This fact poses risks for the establishing of YF enzootic cycles and epidemics, outside the Amazon Basin in Brazil. YF surveillance and studies of viral dynamics deserve particular attention, especially in Midwest, Southeast and neighbor regions which are the main areas historically associated with YF outbreaks outside the Amazon Basin. YFV persistence in Southeast Brazil should be carefully considered in the context of public health, especially for public health decision-makers and researchers.

Mucosal leishmaniasis: the experience of a Brazilian referral center

Abstract INTRODUCTION Pentavalent antimonials (Sbv) are the most commonly used drugs for the treatment of mucosal leishmaniasis (ML), despite their high toxicity and only moderate efficacy. The aim of this study was to report therapeutic responses with different available options for ML. METHODS This study was based on a review of clinical records of 35 patients (24 men and 11 women) treated between 2009 and 2015. RESULTS The median age of patients was 63 years, and the median duration of the disease was 24 months. Seventeen patients received Sbv, while nine patients were treated with liposomal amphotericin B (AmB), and another nine patients were treated with fluconazole. Patients treated with AmB received a total median accumulated dose of 2550mg. The mean duration of azole use was 120 days, and the daily dose ranged from 450 to 900mg. At the three-month follow-up visit, the cure rate was 35%, 67%, and 22% for Sbv, AmB, and azole groups, respectively. At the six-month follow-up visit, the cure rates for Sbv, AmB, and azole groups were 71%, 78%, and 33%, respectively. CONCLUSIONS There is a scarcity of effective ML treatment alternatives, and based on our observations, fluconazole is not a valid treatment option.

Towards a standard protocol for antimony intralesional infiltration technique for cutaneous leishmaniasis treatment

BACKGROUND Despite its recognised toxicity, antimonial therapy continues to be the first-line drug for cutaneous leishmaniasis (CL) treatment. Intralesional administration of meglumine antimoniate (MA) represents an alternative that could reduce the systemic absorption of the drug and its side effects. OBJECTIVES This study aims to validate the standard operational procedure (SOP) for the intralesional infiltration of MA for CL therapy as the first step before the assessment of efficacy and safety related to the procedure. METHODS The SOP was created based on 21 trials retrieved from the literature, direct monitoring of the procedure and consultation with experts. This script was submitted to a formal computer-aided inspection to identify readability, clarity, omission, redundancy and unnecessary information (content validation). For criterion and construct validations, the influence of critical condition changes (compliance with the instructions and professional experience) on outcome conformity (saturation status achievement), tolerability (pain referred) and safety (bleeding) were assessed. FINDINGS The median procedure length was 12 minutes and in 72% of them, patients classified the pain as mild. The bleeding was also classified as mild in 96.6% of the procedures. Full compliance with the SOP was observed in 66% of infiltrations. Despite this, in 100% of the inspected procedures, lesion saturation was observed at the end of infiltration, which means that it tolerates some degree of modification in its execution (robustness) without prejudice to the result. CONCLUSIONS The procedure is reproducible and can be used by professionals without previous training with high success and safety rates.

Towards a standard protocol for antimony intralesional infiltration technique for cutaneous leishmaniasis treatment.

BACKGROUND Despite its recognised toxicity, antimonial therapy continues to be the first-line drug for cutaneous leishmaniasis (CL) treatment. Intralesional administration of meglumine antimoniate (MA) represents an alternative that could reduce the systemic absorption of the drug and its side effects. OBJECTIVES This study aims to validate the standard operational procedure (SOP) for the intralesional infiltration of MA for CL therapy as the first step before the assessment of efficacy and safety related to the procedure. METHODS The SOP was created based on 21 trials retrieved from the literature, direct monitoring of the procedure and consultation with experts. This script was submitted to a formal computer-aided inspection to identify readability, clarity, omission, redundancy and unnecessary information (content validation). For criterion and construct validations, the influence of critical condition changes (compliance with the instructions and professional experience) on outcome conformity (saturation status achievement), tolerability (pain referred) and safety (bleeding) were assessed. FINDINGS The median procedure length was 12 minutes and in 72% of them, patients classified the pain as mild. The bleeding was also classified as mild in 96.6% of the procedures. Full compliance with the SOP was observed in 66% of infiltrations. Despite this, in 100% of the inspected procedures, lesion saturation was observed at the end of infiltration, which means that it tolerates some degree of modification in its execution (robustness) without prejudice to the result. CONCLUSIONS The procedure is reproducible and can be used by professionals without previous training with high success and safety rates.

Meglumine antimoniate intralesional infiltration for localised cutaneous leishmaniasis: a single arm, open label, phase II clinical trial

BACKGROUND Cutaneous leishmaniasis (CL) is a world-wide health problem which currently lacks effective, affordable and easy to use therapy. Recently, the meglumine antimoniate (MA) intralesional infiltration was included among the acceptable therapies for New World leishmaniasis. While this approach is attractive, there is currently little evidence to support its use in Americas. OBJECTIVES The aim of this study was to provide information about effectiveness and safety of a standardised MA intralesional infiltration technique for the treatment of CL. METHODS It is a single-arm phase II clinical trial conducted at a Brazilian referral centre. CL cases with parasitological confirmation presenting a maximum of three CL-compatible skin lesions were treated with weekly MA intralesional infiltration by using a validated technique, up to a maximum of eight infiltrations. RESULTS A total of 53 patients (62 lesions) were included. Overall, patients received a median of seven infiltrations (IQR25-75% 5-8) over a median treatment period of 43 days (IQR25-75% 28-52 days). The definitive cure rate at D180 was 87% (95% CI:77-96%). The majority of adverse events were local, with mild or moderate intensity. Bacterial secondary infection of the lesion site was observed in 13% of the treated patients, beside two intensity-three adverse events (hypersensitivity reactions).