Human parvovirus B19 genotype 1 in suspected dengue patients of Tefé, Amazonas State, Brazil

Abstract INTRODUCTION: Human parvovirus B19 (B19V) is a common pathogen, which on infection causes variety of clinical conditions from benign self-limiting exanthematous disease and other similar pathologies to fetal death. METHODS: We collected 341 serum samples between the first and fourth day after the onset of symptoms from all patients suspected of dengue fever who were attended at Regional Hospital of Tefé. Initially, patients were screened for malaria by blood smear test and negative samples were sent to Fundação de Medicina Tropical Doutor Heitor Vieira Dourado (FMT-HVD) situated in Manaus (AM) for dengue testing using semi-nested multiplex PCR. Further, we investigated 44 malaria and dengue-negative samples of children for B19V DNA by nested-PCR. Positive samples were analyzed by BLAST against entire public non-redundant nucleotide database and genotyped by phylogenetic analyses using neighbor-joining clustering method. RESULTS: Eight samples (18.2%) were found to be PCR positive. Fever, headache, ocular pain, and/or muscle pain were reported as the most frequent symptoms by the patients and none were diagnosed with rash at the time of sample collection. Phylogenetic analysis of major capsid protein 2 (VP2) and VP3 coding region showed high similarity with B19V genotype 1. CONCLUSIONS: Our results reveal the spread of B19V genotype 1 in Tefé. Moreover, our results emphasize the significance of laboratorial differential diagnosis using molecular techniques in patients with acute febrile, and thereby aid the health surveillance system in improving patient care even in the remote areas of Amazon.

Arboviral diseases in the Western Brazilian Amazon: a perspective and analysis from a tertiary health & research center in Manaus, State of Amazonas

The Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), located in Manaus, the capital of the State of Amazonas (Western Brazilian Amazon), is a pioneering institution in this region regarding the syndromic surveillance of acute febrile illness, including arboviral infections. Based on the data from patients at the FMT-HVD, we have detected recurrent outbreaks in Manaus by the four dengue serotypes in the past 15 years, with increasing severity of the disease. This endemicity has culminated in the simultaneous circulation of all four serotypes in 2011, the first time this has been reported in Brazil. Between 1996 and 2009, 42 cases of yellow fever (YF) were registered in the State of Amazonas, and 71.4% (30/42) were fatal. Since 2010, no cases have been reported. Because the introduction of the yellow fever virus into a large city such as Manaus, which is widely infested by Aedes mosquitoes, may pose a real risk of a yellow fever outbreak, efforts to maintain an appropriate immunization policy for the populace are critical. Manaus has also suffered silent outbreaks of Mayaro and Oropouche fevers lately, most of which were misdiagnosed as dengue fever. The tropical conditions of the State of Amazonas favor the existence of other arboviruses capable of producing human disease. Under this real threat, represented by at least 4 arboviruses producing human infections in Manaus and in other neighboring countries, it is important to develop an efficient public health surveillance strategy, including laboratories that are able to make proper diagnoses of arboviruses.

Identification of dengue viruses in naturally infected Aedes aegypti females captured with BioGents (BG)-Sentinel traps in Manaus, Amazonas, Brazil

Introduction In Manaus, the first autochthonous cases of dengue fever were registered in 1998. Since then, dengue cases were diagnosed by the isolation of viruses 1, 2, 3, and 4. Methods One hundred eighty-seven mosquitoes were collected with BioGents (BG)-Sentinel traps in 15 urban residential areas in the Northern Zone of Manaus and processed by molecular tests. Results Infections with dengue viruses 1, 2, 3, and 4 and a case of co-infection with dengue viruses 2 and 3 were identified. Conclusions These findings corroborate the detection of dengue in clinical samples and reinforce the need for epidemiological surveillance by the Health authorities. .

Simultaneous circulation of all four dengue serotypes in Manaus, State of Amazonas, Brazil in 2011 / Circulação simultânea dos quatro sorotipos do vírus dengue em Manaus, Estado do Amazonas, Brasil em 2011

INTRODUCTION: Manaus, the capital city of the state of Amazon with nearly 2 million inhabitants, is located in the middle of the Amazon rain forest and has suffered dengue outbreaks since 1998. METHODS: In this study, blood samples were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), aimed at identifying dengue virus serotypes. RESULTS: Acute phase sera from 432 patients were tested for the presence of dengue virus. Out of the 432 patients, 137 (31.3%) were found to be positive. All the four dengue virus serotypes were observed. CONCLUSIONS: The simultaneous circulation of the four dengue serotypes is described for the first time in Manaus and in Brazil.

INTRODUÇÃO: Manaus, capital do Estado do Amazonas, com quase 2 milhões de habitantes, está localizada no meio da floresta Amazônica e vem sofrendo surtos de dengue desde 1998. MÉTODOS: Neste estudo, amostras de sangue foram investigadas pela Transcriptase reversa-reação em cadeia da polimerase (RT-PCR), visando identificar os sorotipos de vírus da dengue. RESULTADOS: Soros de fase aguda de 432 pacientes foram testados para a presença do vírus da dengue. Destes, 137 (31,3%) foram considerados positivos. Todos os quatro sorotipos do vírus da dengue foram observados. CONCLUSÕES: A circulação simultânea dos quatro sorotipos da dengue é descrita pela primeira vez em Manaus e no Brasil.

Serological evidence of hantavirus infection in rural and urban regions in the state of Amazonas, Brazil

Hantavirus disease is caused by the hantavirus, which is an RNA virus belonging to the family Bunyaviridae. Hantavirus disease is an anthropozoonotic infection transmitted through the inhalation of aerosols from the excreta of hantavirus-infected rodents. In the county of Itacoatiara in the state of Amazonas (AM), Brazil, the first human cases of hantavirus pulmonary and cardiovascular syndrome were described in July 2004. These first cases were followed by two fatal cases, one in the municipality of Maués in 2005 and another in Itacoatiara in 2007. In this study, we investigated the antibody levels to hantavirus in a population of 1,731 individuals from four different counties of AM. Sera were tested by IgG/IgM- enzyme-linked immune-sorbent assay using a recombinant nucleocapsid protein of the Araraquara hantavirus as an antigen. Ten sera were IgG positive to hantavirus (0.6 percent). Among the positive sera, 0.8 percent (1/122), 0.4 percent (1/256), 0.2 percent (1/556) and 0.9 percent (7/797) were from Atalaia do Norte, Careiro Castanho, Itacoatiara and Lábrea, respectively. None of the sera in this survey were IgM-positive. Because these counties are distributed in different areas of AM, we can assume that infected individuals are found throughout the entire state, which suggests that hantavirus disease could be a local emerging health problem.

Presença de parvovírus B19 em Manaus, AM / Occurrence of parvovirus B19 in Manaus, AM

A investigação de 1.107 casos de doenças exantemáticas em Manaus permitiu a identificação dos primeiros 47 casos de parvovírus humano B19 na cidade. O parvovírus B19 foi caracterizado por uma combinação de sinais e sintomas como febre, cefaléia, artralgia, mialgia e exantema. A freqüência de exantema foi maior em indivíduos menores de quinze anos e, no adulto, prevaleceram a febre e artropatias. O maior número de casos foi registrado em 1999. Quanto à faixa etária, nos menores de 15 anos, predominou o sexo masculino e, entre os adultos, o feminino. Este estudo, portanto, ressalta a necessidade de se elucidar a causa de doenças exantemáticas que ocorrem no Estado do Amazonas e indica que estudos são necessários, no que concerne à atividade viral.

Doenças exantemáticas e primeira epidemia de dengue ocorrida em Manaus, Amazonas, no período de 1998-1999 / Exanthematous diseases and the first epidemic of dengue to occur in Manaus, Amazonas State, Brazil, during 1998-1999

Em 1998, a Fundação de Medicina Tropical/Instituto de Medicina Tropical do Amazonas implementou o sistema de vigilância para síndromes febris agudas indiferenciadas, com o propósito de manter vigilância ativa e passiva na Amazônia Ocidental, Brasil, permitindo identificar e diagnosticar os agentes etiológicos causadores de febres agudas. O diagnóstico foi realizado através de estudos sorológicos para a detecção de anticorpos IgM, utilizando-se técnicas de ELISA (Enzyme-linked-immunosorbent assay) e kits ELISA comerciais. Foram analisadas 8.557 amostras de soros de pacientes com suspeita clínica de dengue, 40 por cento dos soros foram ELISA positivos para o vírus da dengue e 26 por cento dos soros foram ELISA positivos para outras doenças exantemáticas virais como rubéola, sarampo, parvovírus, oropouche e mayaro.