ALVINA CLARA FELIX
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina
LIM/52 - Laboratório de Virologia, Hospital das Clínicas, Faculdade de Medicina
LIM/52 - Laboratório de Virologia, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
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- Zika and chikungunya virus infections in hematopoietic stem cell transplant recipients and oncohematological patients(2017) MACHADO, Clarisse Martins; PEREIRA, Barbara Brito de Souza; FELIX, Alvina Clara; OLIVEIRA, Maria Carolina; DARRIGO JR., Luiz Guilherme; SOUZA, Mair Pedro de; PATON, Eduardo Jose de Alencar; NEVES, Fabia; COLTURATO, Vergilio Rensi; SIMOES, Belinda PintoAedes mosquitoes are well adapted in domestic environments and widespread in tropical regions. Since 2015, Brazil has been experiencing a triple epidemic of dengue (DENV), chikungunya (CHKV), and Zika (ZIKV) viruses. The last 2 viruses are likely following the path of DENV, which has been endemic in most parts of the country since the 1980s. Given this triple epidemic, we proposed a prospective and collaborative study to assess the prevalence, morbidity, andmortality of DENV, CHKV, and ZIKV infections in hematopoietic stem cell transplant (HSCT) recipients and oncohematological patients. A case definition strategy (fever and rash) was used to prompt diagnostic investigation of DENV, ZIKV, and CHKV, which was accomplished by real-time polymerase chain reaction with plasma and urine samples. Clinical follow-up was performed 7 and 30 days after symptom onset. We report here the first cases of ZIKV and CHKV infections diagnosed in this ongoing study. From February to May 2016, 9 of the 26 patients (34.6%) fulfilling case definition criteria were diagnosed with DENV (3 cases), ZIKV (4 cases), or CHKV (2 cases) infections. Prolonged viremia and viruria were observed in dengue and Zika fever cases, respectively. Thrombocytopenia was the most frequent complication. Delayed engraftment was noted in 1 patient who acquired ZIKV 25 days before HSCT. All patients survived without sequelae. With the geographic expansion of arboviruses, donor and recipient screening may become mandatory. Patients living in areas where these viruses are not endemic are also at risk, since these viruses can be transmitted by blood as well as organ or tissue transplantation
- Phylogenetics, Epidemiology and Temporal Patterns of Dengue Virus in Araraquara, São Paulo State(2024) SOUZA, Caio Santos de; CALEIRO, Giovana Santos; CLARO, Ingra Morales; JESUS, Jaqueline Goes de; COLETTI, Thais Moura; SILVA, Camila Alves Maia da; COSTA, Angela Aparecida; INENAMI, Marta; RIBEIRO, Andreia C.; FELIX, Alvina Clara; PAULA, Anderson Vicente de; FIGUEIREDO, Walter M.; LUNA, Expedito Jose de Albuquerque; SABINO, Ester C.; ROMANO, Camila M.Dengue virus (DENV) is a prominent arbovirus with global spread, causing approximately 390 million infections each year. In Brazil, yearly epidemics follow a well-documented pattern of serotype replacement every three to four years on average. Araraquara, located in the state of Sao Paulo, has faced significant impacts from DENV epidemics since the emergence of DENV-1 in 2010. The municipality then transitioned from low to moderate endemicity in less than 10 years. Yet, there remains an insufficient understanding of virus circulation dynamics, particularly concerning DENV-1, in the region, as well as the genetic characteristics of the virus. To address this, we sequenced 37 complete or partial DENV-1 genomes sampled from 2015 to 2022 in Araraquara. Then, using also Brazilian and worldwide DENV-1 sequences we reconstructed the evolutionary history of DENV-1 in Araraquara and estimated the time to the most recent common ancestor (tMRCA) for serotype 1, for genotype V and its main lineages. Within the last ten years, there have been at least three introductions of genotype V in Araraquara, distributed in two main lineages (L Ia and L Ib, and L II). The tMRCA for the first sampled lineage (2015/2016 epidemics) was approximately 15 years ago (in 2008). Crucially, our analysis challenges existing assumptions regarding the emergence time of the DENV-1 genotypes, suggesting that genotype V might have diverged more recently than previously described. The presence of the two lineages of genotype V in the municipality might have contributed to the extended persistence of DENV-1 in the region.
- Viral Kinetics in Sylvatic Yellow Fever Cases(2023) I, Vivian Avelino-Silva; THOMAZELLA, Mateus Vailant; MARMORATO, Mariana Prado; CORREIA, Carolina A.; DIAS, Juliana Z. C.; MAESTRI, Alvino; CERQUEIRA, Natalia B.; V, Carlos H. Moreira; BUCCHERI, Renata; FELIX, Alvina C.; ZANELLA, Luiz G. F. A. B. E.; COSTA, Priscilla R.; KALLAS, Esper G.Yellow fever virus viral load was found to be independently associated with mortality, showing the importance of monitoring viremia and suggesting it as a target to improve disease outcome of an endemic disease with high lethality rate in Brazil. Background Yellow fever is a mosquito-borne zoonotic disease caused by yellow fever virus (YFV). Between 2017 and 2019, more than 504 human cases and 176 deaths were confirmed in the outskirts of Sao Paulo city. Throughout this outbreak, studies suggested a potential association between YFV viremia and mortality. Methods Viral ribonucleic acid was measured using reverse-transcription quantitative polymerase chain reaction in plasma samples collected at up to 5 time points, between 3 and 120 days after symptoms onset. Results Eighty-four patients with confirmed YFV infection were included. Most were males, median age was 42, and 30 (36%) died. Deceased patients were older than survivors (P = .003) and had a higher viremia across all time points (P = .0006). Mean values of viremia had a positive, statistically significant correlation with peak values of neutrophils, indirect bilirubin, aspartate transaminase, international normalized ratio, and creatinine. Finally, a Cox proportional hazards model adjusted for age and laboratory variables showed that viremia is independently associated with death, with a mean 1.84-fold increase (84%) in the hazard of death (P < .001) for each unit increase in mean log(10) viremia. Conclusions Our results raise the importance of monitoring YFV viremia and suggest a potential benefit of antiviral drugs or neutralizing monoclonal antibodies early in the course of this infection to improve disease outcomes.
- A spatial case-control study on symptomatic and inapparent primary dengue infections in an endemic city in Brazil(2024) FIGUEIREDO, Gerusa; CHIARAVALLOTI, Francisco; CAMPOS, Sergio; PELLINI, Alessandra Cristina Guedes; FELIX, Alvina Clara; LUNA, ExpeditoWe conducted a spatial case-control study nested in a dengue incidence cohort to explore the role of the spatial and socioeconomic factors in the proportion of symptomatic (cases) and inapparent primary dengue virus infections (controls). Cohort participants were children and adolescents (2 to 16 years of age) at the beginning of the follow-up. Case definitions were, for symptomatic cases, fever plus a positive lab result for acute dengue (NS1, RT-PCR, ELISA IgM/IgG), and for inapparent infection a positive result for dengue IgG (ELISA) in subjects without symptoms and with a previously negative result at baseline. The covariates included sociodemographic factors, residential location, and socioeconomic context variables of the census tracts of residence of cases and controls. We used principal component analysis to reduce the contextual covariates, with the component values assigned to each one based on their residences. The data were modeled in a Bayesian context, considering the spatial dependence. The final sample consisted of 692 children, 274 cases and 418 controls, from the first year of follow-up (2014-2015). Being male, older age, higher educational level of the head of the family and having a larger number of rooms in the household were associated with a greater chance of presenting dengue symptomatic infection at the individual level. The contextual covariates were not associated with the outcome. Inapparent dengue infection has extensive epidemiological consequences. Relying solely on notifications of symptomatic dengue infections underestimates the number of cases, preserves a silent source of the disease, potentially spreading the virus to unaffected areas.