CoronaVac and ChAdOx1 Vaccination and Gamma Infection Elicited Neutralizing Antibodies against the SARS-CoV-2 Delta Variant.

The emergence of new SARS-CoV-2 variants represents a constant threat to world public health. The SARS-CoV-2 Delta variant was identified in late 2020 in India; since then, it has spread to many other countries, replacing other predominant lineages and raising concerns about vaccination efficiency. We evaluated the sensitivity of the Delta variant to antibodies elicited by COVID-19 vaccinated (CoronaVac and ChAdOx1) and convalescent individuals previously infected by earlier lineages and by the Gamma variant. No reduction in the neutralizing efficacy of the Delta variant was observed when compared to B lineage and a reduced neutralization was observed for the Gamma variant. Our results indicate that neutralization of the Delta variant is not compromised in individuals vaccinated by CoronaVac or ChAdOx1; however, a reduction in neutralization efficacy is expected for individuals infected by the Gamma variant, highlighting the importance of continuous vaccination even for previously infected individuals.

Stability of SARS-CoV-2 and other airborne viruses under different stress conditions.

Viral stability under stress conditions may directly affect viral dissemination, seasonality, and pathogenesis. We exposed airborne viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), mumps virus, coxsackievirus B5, human rhinovirus A16, and respiratory syncytial virus, to different temperatures, UV light exposure time, pH values, and osmotic pressures and measured the remaining viral infectivity. Reduced thermal stability was observed for coxsackievirus B5 at 45 °C, while SARS-CoV-2 demonstrated residual infectivity at 55 °C. UV light exposure was an efficient means of viral inactivation but was less efficient for non-enveloped viruses. Rhinovirus A16 and respiratory syncytial virus demonstrated extreme sensitivity to acid conditions, while SARS-CoV-2, rhinovirus A16, and respiratory syncytial virus were unstable in an alkaline environment. The information obtained in this study will be useful for the development of viral inactivation methods and may be correlated with epidemiological and seasonal viral characteristics.

Protective Immunity against Gamma and Zeta Variants after Inactivated SARS-CoV-2 Virus Immunization.

The persistent circulation of SARS-CoV-2 represents an ongoing global threat due to the emergence of new viral variants that can sometimes evade the immune system of previously exposed or vaccinated individuals. We conducted a follow-up study of adult individuals that had received an inactivated SARS-CoV-2 vaccine, evaluating antibody production and neutralizing activity over a period of 6 months. In addition, we performed mice immunization with inactivated SARS-CoV-2, and evaluated the immune response and pathological outcomes against Gamma and Zeta variant infection. Vaccinated individuals produced high levels of antibodies with robust neutralizing activity, which was significantly reduced against Gamma and Zeta variants. Production of IgG anti-S antibodies and neutralizing activity robustly reduced after 6 months of vaccination. Immunized mice demonstrated cellular response against Gamma and Zeta variants, and after viral infection, reduced viral loads, IL-6 expression, and histopathological outcome in the lungs. TNF levels were unchanged in immunized or not immunized mice after infection with the Gamma variant. Furthermore, serum neutralization activity rapidly increases after infection with the Gamma and Zeta variants. Our data suggest that immunization with inactivated WT SARS-CoV-2 induces a promptly responsive cross-reactive immunity response against the Gamma and Zeta variants, reducing COVID-19 pathological outcomes.

Chikungunya Virus Exposure Partially Cross-Protects against Mayaro Virus Infection in Mice.

Chikungunya virus (CHIKV) and Mayaro virus (MAYV) are closely related members of the Semliki Forest virus antigenic complex classified as belonging to the genus Alphavirus of the family Togaviridae. These viruses cause human disease, with sudden fever and joint inflammation that can persist for long periods. CHIKV is the causative agent of large outbreaks worldwide, and MAYV infection represents a growing public health concern in Latin America, causing sporadic cases and geographically limited outbreaks. Considering the relationship between CHIKV and MAYV, the present study aimed to evaluate if preexisting CHIKV immunity protects against MAYV infection. Immunocompetent C57BL/6 mice were intraperitoneally infected with CHIKV and, 4 weeks later, they were infected with MAYV in their hind paw. We observed that the preexistence of CHIKV immunity conferred partial cross-protection against secondary MAYV infection, reducing disease severity, tissue viral load, and histopathological scores. Interestingly, CHIKV antibodies from humans and mice showed low cross-neutralization to MAYV, but neutralizing activity significantly increased after secondary infection. Furthermore, depletion of adaptive immune cells (CD4+ T, CD8+ T, and CD19+ B cells) did not alter the cross-protection phenotype, suggesting that distinct cell subsets or a combination of adaptive immune cells stimulated by CHIKV are responsible for the partial cross-protection against MAYV. The reduction of proinflammatory cytokines, such as interferon gamma (IFN-γ), in animals secondarily infected by MAYV, suggests a role for innate immunity in cross-protection. Our findings shed light on how preexisting immunity to arthritogenic alphaviruses may affect secondary infection, which may further develop relevant influence in disease outcome and viral transmission. IMPORTANCE Mosquito-borne viruses have a worldwide impact, especially in tropical climates. Chikungunya virus has been present mostly in developing countries, causing millions of infections, while Mayaro virus, a close relative, has been limited to the Caribbean and tropical regions of Latin America. The potential emergence and spread of Mayaro virus to other high-risk areas have increased the scientific community's attention to an imminent worldwide epidemic. Here, we designed an experimental protocol of chikungunya and Mayaro virus mouse infection, which develops a measurable and quantifiable disease that allows us to make inferences about potential immunological effects during secondary virus infection. Our results demonstrate that previous chikungunya virus infection is able to reduce the severity of clinical outcomes during secondary Mayaro infection. We provide scientific understanding of immunological features during secondary infection with the closely related virus, thus assisting in better comprehending viral transmission and the pathological outcome of these diseases.

Lying in wait: the resurgence of dengue virus after the Zika epidemic in Brazil.

After the Zika virus (ZIKV) epidemic in the Americas in 2016, both Zika and dengue incidence declined to record lows in many countries in 2017-2018, but in 2019 dengue resurged in Brazil, causing ~2.1 million cases. In this study we use epidemiological, climatological and genomic data to investigate dengue dynamics in recent years in Brazil. First, we estimate dengue virus force of infection (FOI) and model mosquito-borne transmission suitability since the early 2000s. Our estimates reveal that DENV transmission was low in 2017-2018, despite conditions being suitable for viral spread. Our study also shows a marked decline in dengue susceptibility between 2002 and 2019, which could explain the synchronous decline of dengue in the country, partially as a result of protective immunity from prior ZIKV and/or DENV infections. Furthermore, we performed phylogeographic analyses using 69 newly sequenced genomes of dengue virus serotype 1 and 2 from Brazil, and found that the outbreaks in 2018-2019 were caused by local DENV lineages that persisted for 5-10 years, circulating cryptically before and after the Zika epidemic. We hypothesize that DENV lineages may circulate at low transmission levels for many years, until local conditions are suitable for higher transmission, when they cause major outbreaks.

Evidence for current circulation of an ancient West Nile virus strain (NY99) in Brazil.

INTRODUCTION: In Brazil, West Nile virus (WNV) was first detected, in 2018, in horses with neurological disease. AIM: We report the first case of WNV infection in a horse from Ceará state and the complete genome sequence of an isolate from Espírito Santo state. Both infections occurred in 2019. METHODS: WNV was isolated from the tissues of a horse with neurological signs in Espírito Santo and sequenced by MiSeq. RESULTS: Phylogenetic analysis revealed that the isolate belongs to lineage 1a, clustering with the NY99 strain, a strain that has not circulated in the USA since 2005. CONCLUSIONS: Our findings reinforce the hypothesis that WNV has been silently circulating in Brazil for many years.

Coding-Complete Genome Sequence of a Yellow Fever Virus Isolated from a Baby Howler Monkey (Alouatta caraya) from São Paulo State, Brazil, in 2016.

We report a coding-complete sequence of a yellow fever virus, strain JabSPM02, containing the 3' untranslated region and all coding regions. The virus was recovered from an infected howler monkey from a rural area in São Paulo State, Brazil. Our findings show that it belongs to the South America 1E genotype.

Evidence for current circulation of an ancient West Nile virus strain (NY99) in Brazil

Abstract INTRODUCTION: In Brazil, West Nile virus (WNV) was first detected, in 2018, in horses with neurological disease. AIM: We report the first case of WNV infection in a horse from Ceará state and the complete genome sequence of an isolate from Espírito Santo state. Both infections occurred in 2019. METHODS: WNV was isolated from the tissues of a horse with neurological signs in Espírito Santo and sequenced by MiSeq. RESULTS: Phylogenetic analysis revealed that the isolate belongs to lineage 1a, clustering with the NY99 strain, a strain that has not circulated in the USA since 2005. CONCLUSIONS: Our findings reinforce the hypothesis that WNV has been silently circulating in Brazil for many years.

Systems analysis of subjects acutely infected with the Chikungunya virus.

The largest ever recorded epidemic of the Chikungunya virus (CHIKV) broke out in 2004 and affected four continents. Acute symptomatic infections are typically associated with the onset of fever and often debilitating polyarthralgia/polyarthritis. In this study, a systems biology approach was adopted to analyze the blood transcriptomes of adults acutely infected with the CHIKV. Gene signatures that were associated with viral RNA levels and the onset of symptoms were identified. Among these genes, the putative role of the Eukaryotic Initiation Factor (eIF) family genes and apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC3A) in the CHIKV replication process were displayed. We further compared these signatures with signatures induced by the Dengue virus infection and rheumatoid arthritis. Finally, we demonstrated that the CHIKV in vitro infection of murine bone marrow-derived macrophages induced IL-1 beta production in a mechanism that is significantly dependent on the inflammasome NLRP3 activation. The observations provided valuable insights into virus-host interactions during the acute phase and can be instrumental in the investigation of new and effective therapeutic interventions.

West Nile virus infections are here! Are we prepared to face another flavivirus epidemic?

Emerging arthropod-borne viruses (arboviruses), such as chikungunya and Zika viruses, are a major threat to public health in countries like Brazil where biodiversity is high and medical care is sometimes precarious. West Nile fever is a disease caused by the West Nile Virus (WNV), an RNA virus belonging to the Flaviviridae family. It is transmitted by infected mosquitoes to numerous animals like birds, reptiles and mammals, including human and non-human primates. In the last decade, the number of reported cases of WNV infection in humans and animals has increased in the Americas. Circulation of WNV in forests and rural areas in Brazil has been detected based on serological surveys and, in 2014, the first case of West Nile fever was confirmed in a patient from Piauí State. In 2018, the virus was isolated for the first time from a horse from a rural area in the state of Espírito Santo presenting with a neurological disorder; this raises the possibility that other cases of WNV encephalitis may have occurred without clinical recognition and without laboratory diagnosis by specific assays. The imminent WNV outbreak poses a challenge for Brazilian clinicians and researchers. In this review, we summarize the basic biological and ecological characteristics of this virus and the clinical presentation and treatment of febrile illnesses caused by WNV. We also discuss the epidemiological aspects, prophylaxis of WNV infections, and monitoring strategies that could be applied in the possibility of a WNV outbreak in Brazil.

Systems analysis of subjects acutely infected with the Chikungunya virus

The largest ever recorded epidemic of the Chikungunya virus (CHIKV) broke out in 2004 and affected four continents. Acute symptomatic infections are typically associated with the onset of fever and often debilitating polyarthralgia/polyarthritis. In this study, a systems biology approach was adopted to analyze the blood transcriptomes of adults acutely infected with the CHIKV. Gene signatures that were associated with viral RNA levels and the onset of symptoms were identified. Among these genes, the putative role of the Eukaryotic Initiation Factor (eIF) family genes and apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC3A) in the CHIKV replication process were displayed. We further compared these signatures with signatures induced by the Dengue virus infection and rheumatoid arthritis. Finally, we demonstrated that the CHIKV in vitro infection of murine bone marrow-derived macrophages induced IL-1 beta production in a mechanism that is significantly dependent on the inflammasome NLRP3 activation. The observations provided valuable insights into virus-host interactions during the acute phase and can be instrumental in the investigation of new and effective therapeutic interventions.

Systems analysis of subjects acutely infected with the Chikungunya virus

The largest ever recorded epidemic of the Chikungunya virus (CHIKV) broke out in 2004 and affected four continents. Acute symptomatic infections are typically associated with the onset of fever and often debilitating polyarthralgia/polyarthritis. In this study, a systems biology approach was adopted to analyze the blood transcriptomes of adults acutely infected with the CHIKV. Gene signatures that were associated with viral RNA levels and the onset of symptoms were identified. Among these genes, the putative role of the Eukaryotic Initiation Factor (eIF) family genes and apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC3A) in the CHIKV replication process were displayed. We further compared these signatures with signatures induced by the Dengue virus infection and rheumatoid arthritis. Finally, we demonstrated that the CHIKV in vitro infection of murine bone marrow-derived macrophages induced IL-1 beta production in a mechanism that is significantly dependent on the inflammasome NLRP3 activation. The observations provided valuable insights into virus-host interactions during the acute phase and can be instrumental in the investigation of new and effective therapeutic interventions.

West nile virus infections are here! are we prepared to face another flavivirus epidemic?

Abstract Emerging arthropod-borne viruses (arboviruses), such as chikungunya and Zika viruses, are a major threat to public health in countries like Brazil where biodiversity is high and medical care is sometimes precarious. West Nile fever is a disease caused by the West Nile Virus (WNV), an RNA virus belonging to the Flaviviridae family. It is transmitted by infected mosquitoes to numerous animals like birds, reptiles and mammals, including human and non-human primates. In the last decade, the number of reported cases of WNV infection in humans and animals has increased in the Americas. Circulation of WNV in forests and rural areas in Brazil has been detected based on serological surveys and, in 2014, the first case of West Nile fever was confirmed in a patient from Piauí State. In 2018, the virus was isolated for the first time from a horse from a rural area in the state of Espírito Santo presenting with a neurological disorder; this raises the possibility that other cases of WNV encephalitis may have occurred without clinical recognition and without laboratory diagnosis by specific assays. The imminent WNV outbreak poses a challenge for Brazilian clinicians and researchers. In this review, we summarize the basic biological and ecological characteristics of this virus and the clinical presentation and treatment of febrile illnesses caused by WNV. We also discuss the epidemiological aspects, prophylaxis of WNV infections, and monitoring strategies that could be applied in the possibility of a WNV outbreak in Brazil.

Infection with Saint Louis encephalitis virus in the city of Ribeirao Preto, Brazil: report of one case.

Saint Louis encephalitis virus (SLEV) is a mosquito-borne flavivirus from the Americas. In this report we describe aspects of the laboratory diagnosis of a patient with an acute febrile illness induced by SLEV that was initially diagnosed as dengue by positive IgM-ELISA. Infection with this virus is probably not rare in Brazil, but cases remain undiagnosed. It is necessary to improve the surveillance system, including laboratories, for the diagnosis of SLEV in Brazil.

Characterisation of divergent flavivirus NS3 and NS5 protein sequences detected in Rhipicephalus microplus ticks from Brazil.

Transcripts similar to those that encode the nonstructural (NS) proteins NS3 and NS5 from flaviviruses were found in a salivary gland (SG) complementary DNA (cDNA) library from the cattle tick Rhipicephalus microplus. Tick extracts were cultured with cells to enable the isolation of viruses capable of replicating in cultured invertebrate and vertebrate cells. Deep sequencing of the viral RNA isolated from culture supernatants provided the complete coding sequences for the NS3 and NS5 proteins and their molecular characterisation confirmed similarity with the NS3 and NS5 sequences from other flaviviruses. Despite this similarity, phylogenetic analyses revealed that this potentially novel virus may be a highly divergent member of the genus Flavivirus. Interestingly, we detected the divergent NS3 and NS5 sequences in ticks collected from several dairy farms widely distributed throughout three regions of Brazil. This is the first report of flavivirus-like transcripts in R. microplus ticks. This novel virus is a potential arbovirus because it replicated in arthropod and mammalian cells; furthermore, it was detected in a cDNA library from tick SGs and therefore may be present in tick saliva. It is important to determine whether and by what means this potential virus is transmissible and to monitor the virus as a potential emerging tick-borne zoonotic pathogen.

Characterisation of divergent flavivirus NS3 and NS5 protein sequences detected in Rhipicephalus microplus ticks from Brazil

Transcripts similar to those that encode the nonstructural (NS) proteins NS3 and NS5 from flaviviruses were found in a salivary gland (SG) complementary DNA (cDNA) library from the cattle tick Rhipicephalus microplus. Tick extracts were cultured with cells to enable the isolation of viruses capable of replicating in cultured invertebrate and vertebrate cells. Deep sequencing of the viral RNA isolated from culture supernatants provided the complete coding sequences for the NS3 and NS5 proteins and their molecular characterisation confirmed similarity with the NS3 and NS5 sequences from other flaviviruses. Despite this similarity, phylogenetic analyses revealed that this potentially novel virus may be a highly divergent member of the genus Flavivirus. Interestingly, we detected the divergent NS3 and NS5 sequences in ticks collected from several dairy farms widely distributed throughout three regions of Brazil. This is the first report of flavivirus-like transcripts in R. microplus ticks. This novel virus is a potential arbovirus because it replicated in arthropod and mammalian cells; furthermore, it was detected in a cDNA library from tick SGs and therefore may be present in tick saliva. It is important to determine whether and by what means this potential virus is transmissible and to monitor the virus as a potential emerging tick-borne zoonotic pathogen.

Evaluation of cardiac involvement during dengue viral infection.

BACKGROUND: Dengue is a disease whose clinical manifestations range from asymptomatic infections to a severe disease. There have been some previous reports of myocardial involvement in dengue, but this association has not been completely established. METHODS: From January to July of 2011, patients hospitalized with dengue, confirmed through dengue nonstructural protein 1 and/or immunoglobulin M detection, were included in this study and troponin I and N terminal fragment of B-type natriuretic peptide levels were determined. Patients with abnormal biomarkers underwent echocardiography and when any abnormality was detected, they underwent cardiac magnetic resonance imaging. RESULTS: Eighty-one patients were evaluated and 12 patients (15%) presented with elevated biomarker levels. Compared to controls, they had higher leukocyte (P < .001) and platelet counts (P = .005); higher C-reactive protein (P = .02), and a lower viral load (P = .03). There was no difference according to clinical dengue classification; dengue hemorrhagic fever/dengue shock syndrome severity; duration of symptoms; or prevalence of secondary infection between the 2 groups. Two patients died secondary to cardiogenic shock before imaging studies. Necroscopic findings were compatible to myocarditis in both, and immunohistochemistry for dengue virus showed increased staining on mononuclear cells located in the myocardial tissue. Of the 10 patients who underwent echocardiography, depressed left ventricular ejection fraction (LVEF) was identified in 1, left ventricular segmental abnormalities with preserved LVEF in 2, and an important pericardial effusion with tamponade in another. Cardiac involvement was confirmed by CMR in these 4 patients. CONCLUSIONS: Dengue viruses were shown to cause cardiac disease with clinical manifestations ranging from mild elevation of biomarkers to myocarditis and/or pericarditis.

DENV-3 genotype III circulating in São Paulo, Brazil,from 2003 to 2008 is not associated with dengue haemorrhagic fever/dengue shock syndrome.

Dengue viruses (DENV) are the most important arboviruses of public health significance, and compriseof four distinct antigenic serotypes (DENV-1 to 4) that show substantial genetic diversity. These virusesusually cause dengue fever (DF) but some patients progress to a more severe form of the illness, i.e.dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS). The first reports of DENV-3 cases inBrazil occurred in the year 2000 with co-circulation of DENV-1 and 2. Thereafter, DENV-3 spreadthroughout the country. DENV-3 phylogenetic analysis has revealed the existence of four to five DENV-3 genotypes. Genotype III of DENV-3 has been the main genotype circulating in Brazil, but recent studieshave indicated that DENV-3 genotype I and genotype V are also circulating in some states of Brazil. Inorder to evaluate DENV-3 genotypes circulating in São Paulo state from 2003 through 2008 we analyzedthe NS1 region of DENV-3 isolated from patients residing in Ribeirão Preto and presenting with differentclinical manifestations of dengue disease. Nucleotide sequences from 31 viruses were obtained andcompared to 105 DENV-3 corresponding sequences retrieved from GenBank. Phylogenetic analysisshowed that São Paulo DENV-3 sequences belong to genotype III and that Puerto Rico strains are closelyrelated to South American strains. There was no association between DENV-3 genotype and DHF/DSS.