[Bioterrorism and pathogenic microorganisms].

In recent years the use of pathogenic microorganisms in acts of bioterrorism has been the subject of major concern in many countries. This paper presents a possible application of viruses and bacteria for warfare and terrorist purposes, as well as a laboratory diagnosis to identify those agents. The viruses of smallpox (orthopoxvirus), of hemorrhagic fever and those belonging to filovirus have been highlighted, inter alia, as agents of human infection with bioterrorist intent.

Ilheus virus isolation in the Pantanal, west-central Brazil.

The wetlands of the Brazilian Pantanal host large concentrations of diverse wildlife species and hematophagous arthropods, conditions that favor the circulation of zoonotic arboviruses. A recent study from the Nhecolândia sub-region of Pantanal reported serological evidence of various flaviviruses, including West Nile virus and Ilheus virus (ILHV). According to the age of seropositive horses, at least three flaviviruses, including ILHV, circulated in the Brazilian Pantanal between 2005 and 2009.

Evaluation of a generic RT-nested-PCR for detection of flaviviruses in suspected fatal cases of dengue infection, Rio de Janeiro, Brazil.

Flaviviruses are significant causes of disease worldwide and can be classified serologically into several antigenic complexes. The purpose of the present study was to evaluate the effectiveness of a generic RT-nested-PCR for detection of flavivirus during a dengue outbreak in Brazil in 2008. A total of 105 serum samples were collected from patients with fatal outcome and examined by generic RT-PCR, conventional RT-PCR, and IgM serology.

Neutralising antibodies for West Nile virus in horses from Brazilian Pantanal.

Despite evidence of West Nile virus (WNV) activity in Colombia, Venezuela and Argentina, this virus has not been reported in most South American countries. In February 2009, we commenced an investigation for WNV in mosquitoes, horses and caimans from the Pantanal, Central-West Brazil. The sera of 168 horses and 30 caimans were initially tested using a flaviviruses-specific epitope-blocking enzyme-linked immunosorbent assay (blocking ELISA) for the detection of flavivirus-reactive antibodies.

A new approach to dengue fatal cases diagnosis: NS1 antigen capture in tissues.

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Background: Dengue is the most important arthropod borne viral disease worldwide in terms of morbidity and mortality and is caused by any of the four serotypes of dengue virus (DENV-1 to 4). Brazil is responsible for approximately 80% of dengue cases in the Americas, and since the introduction of dengue in 1986, a total of 5,944,270 cases have been reported including 21,596 dengue hemorrhagic fever and 874 fatal cases. DENV can infect many cell types and cause diverse clinical and pathological effects.

Comparison of three commercially available dengue NS1 antigen capture assays for acute diagnosis of dengue in Brazil.

Background: Dengue is associated with explosive urban epidemics and has become a major public health problem in many tropical developing countries, including Brazil. The laboratory diagnosis of dengue can be carried out using several approaches, however sensitive and specific assays useful to diagnose in the early stage of fever are desirable. The flavivirus non-structural protein NS1, a highly conserved and secreted glycoprotein, is a candidate protein for rapid diagnosis of dengue in endemic countries.

[Human infections caused by vaccinia-like poxviruses in Brazil].

Since 1999, human infection caused by Orthopoxvirus has been observed in at least eight Brazilian states, with the presence of vesicles that evolve to pustules and crusts, especially on the hands, arms and face, after contact with cows showing comparable lesions on the udder. In addition to the skin lesions, there have been descriptions of patients with axillary ganglionic reactions that are sometimes painful, along with fever, headache, fatigue, dehydration, anorexia, sudoresis, arthralgia and muscle pain. The condition evolves over a three to four-week period.

Dengue virus type 3 in Brazil: a phylogenetic perspective.

Circulation of a new dengue virus (DENV)-3 genotype was recently described in Brazil and Colombia, but the precise classification of this genotype has been controversial. Here we perform phylogenetic and nucleotide-distance analyses of the envelope gene, which support the subdivision of DENV-3 strains into five distinct genotypes (GI to GV) and confirm the classification of the new South American genotype as GV. The extremely low genetic distances between Brazilian GV strains and the prototype Philippines/L11423 GV strain isolated in 1956 raise important questions regarding the origin of GV in South America.

Quantification of dengue virus type 3 RNA in fatal and non-fatal cases in Brazil, 2002.

We examined levels of dengue virus type 3 (DENV-3) RNA in association with the type of infection (primary or secondary) in 42 patients with fatal and non-fatal outcomes in Rio de Janeiro, Brazil, 2002. Subjects with fatal outcomes had mean virus titers significantly higher than those who survived (12.5 vs.

Phylogeography and evolutionary history of dengue virus type 3.

In this study, we revisited the phylogeography of the three of major DENV-3 genotypes and estimated its rate of evolution, based on the analysis of the envelope (E) gene of 200 strains isolated from 31 different countries around the world over a time period of 50 years (1956-2006). Our phylogenetic analysis revealed a geographical subdivision of DENV-3 population in several country-specific clades. Migration patterns of the main DENV-3 genotypes showed that genotype I was mainly circumspect to the maritime portion of Southeast-Asia and South Pacific, genotype II stayed within continental areas in South-East Asia, while genotype III spread across Asia, East Africa and into the Americas.

[Human infection by the cowpox virus in the microregion of Itajubá, state of Minas Gerais: case report].

The authors report three human cases of cowpox infection, among farm workers who were manually milking infected cows, in the microregion of Itajubá, Minas Gerais. The diagnostic techniques used were: isolation of samples similar to the vaccinia virus, from skin lesion secretions; polymerase chain reaction; electronic microscopy; and antibodies for Orthopoxvirus in the patients' blood.

A retrospective survey of dengue virus infection in fatal cases from an epidemic in Brazil.

Dengue virus can infect many cell types from the vascular, muscular and hematological systems causing diverse clinical and pathological signs. The purpose of the present study was to investigate by different diagnostic methods dengue virus in human tissue specimens obtained from fatal cases (n=29) during a large-scale dengue fever epidemic in 2002 in the State of Rio de Janeiro, Brazil. The combination of four procedures provided diagnostic confirmation of DENV-3 infection in 26 (89.

Phylogenetic and genetic analysis of feline immunodeficiency virus gag, pol, and env genes from domestic cats undergoing nucleoside reverse transcriptase inhibitor treatment or treatment-naïve cats in Rio de Janeiro, Brazil.

Feline immunodeficiency virus (FIV) is the Lentivirus responsible for an immunodeficiency-like disease in domestic cats (Felis catus). FIV is divided into five phylogenetic subtypes (A, B, C, D, and E), based on genetic diversity. Knowledge of the geographical distribution of subtypes is relevant for understanding different disease progressions and for vaccine development.

Dengue and dengue hemorrhagic fever in the State of Pernambuco, 1995-2006.

In Pernambuco, the first dengue cases occurred in 1987. After a seven-year interval without autochthonous cases, a new epidemic occurred in 1995. Important aspects of the dengue epidemics during the period 1995-2006 have been analyzed here, using epidemiological, clinical and laboratory data.

Dengue viruses in Brazil, 1986-2006.

A total of 4,243,049 dengue cases have been reported in Brazil between 1981 and 2006, including 5,817 cases of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) and a total of 338 fatal cases. Although all Brazilian regions have been affected, the Northeast and Southeast regions have registered the highest number of notifications. DENV-1 and DENV-4 were isolated for the first time in the Amazon region of Brazil in 1981 and 1982.

Histopathological and ultrastructural aspects of mice lungs experimentally infected with dengue virus serotype 2.

Histological and ultrastructural alterations in lung tissue of BALB/c mice infected with dengue virus serotype 2 (non-neuroadapted), by intraperitoneal and intravenous routes were analyzed. Lung tissues were processed following the standard techniques for photonic and electron transmission microscopies. Histopathological and ultrastructural studies showed interstitial pneumonia, characterized by the presence of mononuclear cells.

Recombinant polypeptide antigen-based immunoglobulin G enzyme-linked immunosorbent assay for serodiagnosis of dengue.

We have developed an indirect enzyme-linked immunosorbent assay for detection of anti-dengue virus (DENV) immunoglobulin G antibodies using four recombinant DENV envelope polypeptides as antigens, which demonstrated a sensitivity of 89.4% and a specificity of 93.3%.

Morphological studies in a model for dengue-2 virus infection in mice.

One of the main difficulties in studying dengue virus infection in humans and in developing a vaccine is the absence of a suitable animal model which develops the full spectrum of dengue fever, dengue haemorrhagic fever, and dengue shock syndrome. It is our proposal to present morphological aspects of an animal model which shows many similarities with the dengue infection in humans. BALB/c mice were intraperitoneally infected with non-neuroadapted dengue virus serotype 2 (DENV-2).

Dengue virus type 3, Brazil, 2002.

During the summer of 2002, Rio de Janeiro had a large epidemic of dengue fever; 288,245 cases were reported. A subset of 1,831 dengue hemorrhagic fever cases occurred. In this study, performed in the first half of 2002, samples from 1,559 patients with suspected cases of dengue infection were analyzed.

Dengue virus detection by using reverse transcription-polymerase chain reaction in saliva and progeny of experimentally infected Aedes albopictus from Brazil.

Oral susceptibility and vertical transmission of dengue virus type 2 (DENV-2) in an Aedes albopictus sample from Rio de Janeiro was estimated. The infection (36.7%) and transmission (83.

Analysis of recombinant dengue virus polypeptides for dengue diagnosis and evaluation of the humoral immune response.

Dengue is a serious cause of morbidity and mortality in tropical areas worldwide. We cloned and expressed recombinant polypeptides spanning the entire genome of a Brazilian dengue virus type 2 (DENV-2) strain in contiguous segments to generate antigens for dengue diagnosis and evaluation of the human humoral immune response. When analyzed by Western blot and an enzyme-linked immunosorbent assay (ELISA) using human sera, the most reactive polypeptide (pD2-3(E)) was located in the N-terminal portion of the envelope protein.

Dengue viruses activity in Piauí, Brazil.

The present paper reports a laboratory investigation performed between the years of 2000 and 2002 to study a virological surveillance program introduced in the state of Piauí to support an epidemiological survey of the disease. Dengue virus type 3 (DENV-3) existence in the state was detected in May 2002 when a high number of dengue cases due to DENV-1 and DENV-2 were reported. An assessment on the population knowledge about the disease and its transmission showed that almost 50% of the population were still unaware of the epidemiological features of dengue.

Isolation and characterization of wild type yellow fever virus in cases temporally associated with 17DD vaccination during an outbreak of yellow fever in Brazil.

A mass vaccination was carried out in the state of Minas Gerais, Southeast region of Brazil, to control an outbreak of sylvatic yellow fever in 2001. During the outbreak the surveillance system identified two fatal cases temporally associated with YF vaccination. Virus recovered from blood and postmortem samples of both cases was identified as yellow fever virus.