Felipe Scassi Salvador

Entry routes for Zika virus in Brazil after 2014 world cup: New possibilities.

In the beginning of 2015, several cases of Dengue and Chikungunya virus infections were reported in Brazil [1]. Dengue epidemics are located in the states of São Paulo (637,029 confirmed cases), Minas Gerais (166,360 confirmed cases), Goiás (121,501 confirmed cases), Pernambuco (68,510 confirmed cases), Ceará (59,074 confirmed cases), Rio de Janeiro (49,480 confirmed cases), Paraná (46,694 confirmed cases), Bahia (42,476 confirmed cases), Rio Grande do Norte (21,194 confirmed cases), Mato Grosso do Sul (18,663 confirmed cases), Paraı́ba (18,018 confirmed cases), Espı́rito Santo (16,477 confirmed cases), Alagoas (13,846 confirmed cases) e Mato Grosso (13,700 confirmed cases). For Chikungunya virus infection, the state of Bahia appears as first in number of confirmed cases (7820), followed by Amapá (1070) and Federal District (194). Zika virus infections presented clinical pictures very similar to dengue, and the number of cases reported officially are low, provided by problems in detection as it occurs in a dengue virus area and co -infection of these viruses is not uncommon [2]. The strongest hypothesis of the introduction of Zika virus in Brazil has bought by African travelers during the 2014 World Cup has virus transmission by asymptomatic patients, aside to significant increase of

Inter- and Intra-Host Viral Diversity in a Large Seasonal DENV2 Outbreak

Background High genetic diversity at both inter- and intra-host level are hallmarks of RNA viruses due to the error-prone nature of their genome replication. Several groups have evaluated the extent of viral variability using different RNA virus deep sequencing methods. Although much of this effort has been dedicated to pathogens that cause chronic infections in humans, few studies investigated arthropod-borne, acute viral infections. Methods and Principal Findings We deep sequenced the complete genome of ten DENV2 isolates from representative classical and severe cases sampled in a large outbreak in Brazil using two different approaches. Analysis of the consensus genomes confirmed the larger extent of the 2010 epidemic in comparison to a previous epidemic caused by the same viruses in another city two years before (genetic distance = 0.002 and 0.0008 respectively). Analysis of viral populations within the host revealed a high level of conservation. After excluding homopolymer regions of 454/Roche generated sequences, we found 10 to 44 variable sites per genome population at a frequency of >1%, resulting in very low intra-host genetic diversity. While up to 60% of all variable sites at intra-host level were non-synonymous changes, only 10% of inter-host variability resulted from non-synonymous mutations, indicative of purifying selection at the population level. Conclusions and Significance Despite the error-prone nature of RNA-dependent RNA-polymerase, dengue viruses maintain low levels of intra-host variability.

Glytube: A Conical Tube and Parafilm M-Based Method as a Simplified Device to Artificially Blood-Feed the Dengue Vector Mosquito, Aedes aegypti

Aedes aegypti, the main vector of dengue virus, requires a blood meal to produce eggs. Although live animals are still the main blood source for laboratory colonies, many artificial feeders are available. These feeders are also the best method for experimental oral infection of Ae. aegypti with Dengue viruses. However, most of them are expensive or laborious to construct. Based on principle of Rutledge-type feeder, a conventional conical tube, glycerol and Parafilm-M were used to develop a simple in-house feeder device. The blood feeding efficiency of this apparatus was compared to a live blood source, mice, and no significant differences (p = 0.1189) were observed between artificial-fed (51.3% of engorgement) and mice-fed groups (40.6%). Thus, an easy to assemble and cost-effective artificial feeder, designated “Glytube” was developed in this report. This simple and efficient feeding device can be built with common laboratory materials for research on Ae. aegypti.

Potential measles transmission risk in mass gatherings: Are we safe for the Olympic games--Rio 2016?

The measles virus, genus Morbillivirus of the Paramyxoviridae family, only infects humans. Measles is transmitted by droplets when the infected individual is coughing or sneezing. It is highly infectious (R0 = 15–20 in a completely susceptible population),1 especially in closed environments such as shopping malls, schools and other confined places. Infected individuals can shed the virus up to 4 days before the appearance of their symptoms and up to 4 days after the onset of symptoms.2 Also, its RNA is still detected in biological samples for many weeks.3 Measles is characterized by its high infectivity. The initial clinical manifestations include runny nose, cough, red and watery eyes and small white spots inside the cheeks. After several days, a maculo-papular exanthema erupts.4 Measles was controlled in some regions, including Brazil. Recently, some outbreaks were reported in the country in the past few years and may represent a risk for transmission during mass gathering events, such as the Olympic Games. For that reason, the aim of this article is to discuss the potential risk for Measles transmission in the country during the Olympic Games and also preventive measures in order to avoid other outbreaks. The number of suspected and confirmed measles cases in 2015 reported by WHO5 indicates a frame, in which the African Region presents the highest number of confirmed cases, whereas Region of Americas presents the lowest: African Region (54 374 suspect/35 557 confirmed), Region of the Americas (13 083 suspect/366 confirmed), Eastern Mediterranean Region (26 178 suspect/11 610 confirmed), European Region (6642 suspect/6023 confirmed), South-East Asia Region (79 713 suspect/67 233 confirmed) and Western Pacific Region (120 319 suspect/61 493 confirmed). This represents a total of 300.309 suspect cases and 182.282 confirmed cases in the world until October 2015. WHO indicates that from June 2014 to June 2015 in the European Continent, there were more …

Production of a Recombinant Dengue Virus 2 NS5 Protein and Potential Use as a Vaccine Antigen

ABSTRACT Dengue fever is caused by any of the four known dengue virus serotypes (DENV1 to DENV4) that affect millions of people worldwide, causing a significant number of deaths. There are vaccines based on chimeric viruses, but they still are not in clinical use. Anti-DENV vaccine strategies based on nonstructural proteins are promising alternatives to those based on whole virus or structural proteins. The DENV nonstructural protein 5 (NS5) is the main target of anti-DENV T cell-based immune responses in humans. In this study, we purified a soluble recombinant form of DENV2 NS5 expressed in Escherichia coli at large amounts and high purity after optimization of expression conditions and purification steps. The purified DENV2 NS5 was recognized by serum from DENV1-, DENV2-, DENV3-, or DENV4-infected patients in an epitope-conformation-dependent manner. In addition, immunization of BALB/c mice with NS5 induced high levels of NS5-specific antibodies and expansion of gamma interferon- and tumor necrosis factor alpha-producing T cells. Moreover, mice immunized with purified NS5 were partially protected from lethal challenges with the DENV2 NGC strain and with a clinical isolate (JHA1). These results indicate that the recombinant NS5 protein preserves immunological determinants of the native protein and is a promising vaccine antigen capable of inducing protective immune responses.

Complete Genome Sequence of an Atypical Dengue Virus Serotype 2 Lineage Isolated in Brazil

ABSTRACT Here, we report the complete polyprotein sequence of a dengue virus 2 strain isolated in Brazil. This virus belongs to the American genotype and has the ability to cause neurovirulence in immunocompetent adult mice. The data presented here may help understand the genetic determinants responsible for neurovirulence.

Evaluation of Possible Consequences of Zika Virus Infection in the Developing Nervous System.

The Zika virus (ZIKV) outbreak that occurred in the northeast of Brazil in 2015 led to alarming numbers of babies born with microcephaly in this region. Since then, several studies have evaluated the relationship between ZIKV infection and development of the malformation although the specific mechanistic interaction between ZIKV and human physiological processes that ultimately manifest as microcephaly remains debated. Importantly, most current studies did not consider the specificities of the biology and life cycle of ZIKV. As a consequence, specificities of the infection on the developing central nervous system (CNS) were frequently disregarded. In order to begin to address this important gap in our knowledge, we have collated and critically reviewed the existing evidence in this area to identify any emerging consensus on this topic and thereafter describe possible mechanisms by which ZIKV infection could interfere with specific processes of CNS development, such as neuronal proliferation, and the complex interactions of immature neurons with radial glial cells. With this, we were able to present the current knowledge on this important topic in the neurobiology field.

The silent spread of West Nile virus in Brazil: non-human positive case in a beach tourist destination—Espirito Santo

Dear Editor, West Nile virus (WNV) is an emerging arbovirus related to a neurotropic flavivirus that usually infects birds, and can be accidentally transmitted to other animals, including humans. Positive cases in humans are mainly asymptomatic (8 of 10 infected individuals), but a small portion present fever (1 in 5 infected individuals) with headache, myalgia, arthralgia, vomiting, diarrhoea or rash, common symptoms of other flaviviruses. The severe illness, with important neurological consequences, may affect only 1 in 150 of infected patients. Specific diagnostic tests are crucial for surveillance and local control. Evidence of the viral circulation in Brazil was reported in equids in Amazon and Pantanal areas in 2009. The spread to the northeast region of the country, with positive cases in equids and birds, occurred in 2013. One year later, the first human case was detected (Piauí State). WNV was silently transmitted, arriving now in Brazilian’s Southeast Region (Figure 1) according to the report of one equid death in 2018, June in Espírito Santo State, an important domestic tourist destination in Brazil, which currently presents other arboviruses’ outbreaks as Zika (n = 219 reported cases), Chikungunya (n = 482 reported cases) and Dengue (n = 6.945 reported cases). The persistence of other arboviruses in the autumn/winter period points to the vectors population increasing in the region (including Aedes aegypti, Culex quinquefasciatus and others), a similar condition that affects other Brazilian states. Considering that the virus infects birds, equids and also humans, areas with high-population density may be in alert (previous cases occurred in uninhabited locations) due to the fast spread of other arboviruses in the state. The existence of a similar favourable causal network in the USA contributed to the WNV epidemic in 1999. We recommend, especially for domestic travellers, the use of mosquito repellents, especially icaridin, and to wear pants and shirts with long sleeves when visiting natural areas in Espírito Santo State. Unfortunately, there is no cure or vaccine for humans against WNV, only palliative treatment for the symptoms. Other protective measures may be established such as public campaigns for mass information (including preventive instructions to avoid the disease) and the elimination of mosquito breeding sites in the urban areas (to reduce the transmission of arboviruses). Other actions of eco-epidemiological surveillance by the municipal and state government, aiming at fast identification of probable hosts in urban and peri-urban areas may become urgent.