Danila Vedovello

Isolation and characterization of mayaro virus from a human in Acre, Brazil

Mayaro virus (MAYV) is widely distributed throughout South America and is the etiologic agent of Mayaro fever, an acute febrile illness often presenting with arthralgic manifestations. The true incidence of MAYV infection is likely grossly underestimated because the symptomatic presentation is very similar to that of dengue fever and other acute febrile tropical diseases. We report the complete genome sequence of a MAYV isolate detected from an Acrelândia patient presenting with fever, chills, and sweating, but with no arthralgia. Results show that this isolate belongs to genotype D and is closely related to Bolivian strains. Our results suggest that the Acre/Mayaro strain is closely related to the progenitor of these Bolivian strains that were isolated between 2002 and 2006.

Dengue-4 false negative results by Panbio ® Dengue Early ELISA assay in Brazil

BACKGROUND Dengue is a serious public health problem in numerous countries. The ability to rapidly diagnosis dengue is important for patient triage and management. Detection of dengue viral protein, NS1, represents a new approach to dengue diagnosis. OBJECTIVE The present study aims to evaluate if there are false negative results using the NS1 Ag rapid assay (Panbio(®) Dengue Early ELISA) in two different epidemiological situations (epidemic and non-epidemic). STUDY DESIGN 220 serum samples from patients with clinical symptoms of classical dengue fever were tested by NS1 antigen capture ELISA and Multiplex-Nested-PCR. RESULTS In samples collected in a non-epidemic period we found a 100% agreement of ELISA and RT-PCR in dengue negative samples and 85% agreement of ELISA and RT-PCR in dengue positive samples. But when we tested samples during an epidemic period (large DENV-4 outbreak) we found 15% false negative results (p<0.05) in dengue negative samples. CONCLUSIONS Due to false negative results for DENV-4, the sole use of the Panbio(®) Dengue Early ELISA assay as a screening method for monitoring circulating dengue serotypes must be reevaluated.

Complete Genome Sequence of Mayaro Virus Imported from the Amazon Basin to São Paulo State, Brazil

ABSTRACT Mayaro (MAYV) is a neglected arbovirus from the tropical Americas. Here, we report the complete genome of an MAYV isolate from a patient returning from the Amazon basin and complaining of arthralgia, high fever, and headache, who was attended at an emergency service of São José do Rio Preto, São Paulo state, Brazil.

CO-INFECTION OF DENGUE VIRUS BY SEROTYPES 1 AND 4 IN PATIENT FROM MEDIUM SIZED CITY FROM BRAZIL

SUMMARY The natural co-infection with dengue virus can occur in highly endemic areas where different serotypes have been observed for many years. We report one case of DENV-1/DENV-4 co-infection in human serum detected by molecular tests. Phylogenetic analysis of the sequences obtained indicated the presence of genotype V and II for DENV-1 and DENV-4, respectively.

Dengue virus surveillance: Detection of DENV-4 in the city of São José do Rio Preto, SP, Brazil.

Dengue viruses are the most common arbovirus infection worldwide and are caused by four distinct serotypes of the dengue virus (DENV). In the present study, we assessed DENV transmission in São José do Rio Preto (SJRP) from 2010 to 2014. We analyzed blood samples from febrile patients who were attended at health care centers in SJRP. DENV detection was performed using multiplex RT-PCR, using flavivirus generic primers, based on the genes of the non-structural protein (NS5), followed by nested-PCR assay with species-specific primers. We analyzed 1549 samples, of which 1389 were positive for NS1 by rapid test. One thousand and eight-seven samples (78%) were confirmed as positive by multiplex RT-PCR: DENV-4, 48.5% (528/1087); DENV-1, 41.5% (449/1087); DENV-2, 9.5% (104/1087); and co-infection (5 DENV-1/DENV-4, 1 DENV-1/DENV-2), 0.5% (6/1087). Phylogenetic analysis of the DENV-4 grouped the isolates identified in this study with the American genotype and the showed a relationship between isolates from SJRP and isolates from the northern region of South America. Taken together, our data shows the detection and emergence of new dengue genotype in a new region and reiterate the importance of surveillance programs to detect and trace the evolution of DENV.

First genome sequence of St. Louis encephalitis virus (SLEV) isolated from a human in Brazil

St. Louis encephalitis virus (SLEV), a member of the family Flaviviridae, genus Flavivirus, is a causative agent of encephalitis in the Americas. In Brazil, sporadic cases of SLEV infection have been reported since 1953, but the first outbreak of SLEV in Brazil was identified only in 2007, concomitant with an outbreak of dengue virus (DENV) serotype 3. This finding, along with other reports, indicates that SLEV circulation in Brazil is largely unknown, and there may be epidemiological implications of the co-circulation of SLEV, DENV and other flaviviruses in Brazil. Here, we describe the first complete genome sequence of an SLEV strain isolated from a human patient in Brazil, strain BeH 355964. Phylogenetic analysis was performed to determine the genotype of BeH 355964 using the full-length genome and envelope (E) gene sequences separately. Both analyses showed that BeH 355964 could be classified as genotype V. Although the number of single gene sequences available is greater (such as for the E gene), the phylogenetic tree based on the complete genome sequence was better supported and provided further information about the virus.

Isolation and Characterization of Madariaga Virus from a Horse in Paraiba State, Brazil

Madariaga virus (MADV), the new species designation for the South American isolates of eastern equine encephalitis virus (EEEV), is genetically divergent and substantially different in ecology and pathogenesis from North American EEEV strains. We isolated and characterized a MADV isolate obtained from a horse in Brazil. Our results support previous phylogenetic studies showing there are three genetically distinct MADV lineages. The MADV isolate from Paraíba State belongs to the South American lineage III and is closely related to Peruvian, Colombian and Venezuelan isolates.

Mayaro fever in an HIV-infected patient suspected of having Chikungunya fever

Arboviruses impose a serious threat to public health services. We report a case of a patient returning from a work trip to the Amazon basin with myalgia, arthralgia, fever, and headache. During this travel, the patient visited riverside communities. Both dengue and Chikungunya fevers were first suspected, tested for, and excluded. Mayaro fever was then confirmed by reverse transcription polymerase chain reaction followed by next-generation sequencing and phylogenetic reconstruction. The increased awareness of physicians and consequent detection of Mayaro virus in this case was only possible due a previous surveillance program with specific health personnel training about these neglected arboviruses.

Viral immunogenicity determines epidemiological fitness in a cohort of DENV-1 infection in Brazil

The dynamics of dengue virus (DENV) circulation depends on serotype, genotype and lineage replacement and turnover. In São José do Rio Preto, Brazil, we observed that the L6 lineage of DENV-1 (genotype V) remained the dominant circulating lineage even after the introduction of the L1 lineage. We investigated viral fitness and immunogenicity of the L1 and L6 lineages and which factors interfered with the dynamics of DENV epidemics. The results showed a more efficient replicative fitness of L1 over L6 in mosquitoes and in human and non-human primate cell lines. Infections by the L6 lineage were associated with reduced antigenicity, weak B and T cell stimulation and weak host immune system interactions, which were associated with higher viremia. Our data, therefore, demonstrate that reduced viral immunogenicity and consequent greater viremia determined the increased epidemiological fitness of DENV-1 L6 lineage in São José do Rio Preto.

Complete Genome Sequences of Two Dengue Virus Serotype 1 Genotype V Strains from Different Lineages

ABSTRACT Previous phylogenetic studies involving dengue virus serotype 1 (DENV1) have shown several lineages of genotype V circulating worldwide. After sequencing the complete genome of strains from São José do Rio Preto, São Paulo, Brazil, we identified a list of 50 different amino acids that differ between the two lineages, announced here.