Hantavirus pulmonary syndrome, central plateau, southeastern, and southern Brazil.

Hantavirus pulmonary syndrome (HPS) is an increasing health problem in Brazil because of encroachment of sprawling urban, agricultural, and cattle-raising areas into habitats of subfamily Sigmodontinae rodents, which serve as hantavirus reservoirs. From 1993 through June 2007, a total of 884 cases of HPS were reported in Brazil (case-fatality rate 39%). To better understand this emerging disease, we collected 89 human serum samples and 68 rodent lung samples containing antibodies to hantavirus from a 2,500-km-wide area in Brazil. RNA was isolated from human samples and rodent tissues and subjected to reverse transcription-PCR. Partial sequences of nucleocapsid protein and glycoprotein genes from 22 human and 16 rodent sources indicated only Araraquara virus and Juquitiba virus lineages. The case-fatality rate of HPS was higher in the area with Araraquara virus. This virus, which may be the most virulent hantavirus in Brazil, was associated with areas that have had greater anthropogenic changes.

Pinhal Virus, a New Arenavirus Isolated from Calomys tener in Brazil.

Arenavirus Sabiá was originally isolated from a fatal human infection in Brazil, and after the occurrence of the second fatal human case in São Paulo state, epidemiologic and virologic studies were performed in the area where the patient lived, aiming at the identification of the Sabiá natural rodent reservoir. A broadly cross-reactive enzyme-linked immunosorbent assay (ELISA) was used to screen for antibody-positive samples. Antibodies to arenavirus were detected in two of the 55 samples of Calomys tener, and from these results, samples of rodents were analyzed by a broad RT-PCR assay. RT-PCR amplification detected arenavirus sequences in five of the 55 C. tener samples, and sequencing showed that this virus is a distinct form of Sabiá virus. Thus, we describe here the evidence for the circulation of a new arenavirus in Brazil (proposed name Pinhal virus) and its genetic characterization compared to other arenaviruses. This study also suggests C. tener as a probable rodent reservoir for this virus and associates this new virus with the lineage C of New World arenaviruses. Although we have defined some characteristics of this virus, so far, there is no evidence of its involvement in human disease.

Characterization of hantaviruses circulating in Central Brazil.

In 2004, an outbreak of HCPS in Brazil made hantaviruses a national threat to the rural and urban population. During this outbreak, 164 cases were reported, and 18.3% of them occurred in the Federal District. In this study, hantavirus genomic sequences were amplified from seven patients who resided in Central Brazil and then sequenced and compared to other hantavirus sequences. The complete S segment sequence, which is 1847 bases long and potentially encodes the 428 amino acid nucleocapsid protein, was determined for one patient. Moreover, a 700 base-pair sequence of the S segment was obtained from two other patients, and we analyzed M segment sequences from all samples. It can be inferred by both identity and phylogenetic analysis that the sequences obtained are highly related to Araraquara variant and Maciel virus. Phylogenetic results show that hantaviruses isolated in Central Brazil can be divided into two monophyletic groups: one group that clusters with Araraquara variant and the other group that includes the complete S segment sequence obtained in this study. Therefore, we propose the name Paranoa for this variant that co-exists with the Araraquara-like hantavirus in Central Brazil.

Lectins for the detection of IgM antibodies to T. gondii in the diagnosis of acute toxoplasmosis by immunofluorescence test

Lectinas foram marcadas com fluoresceína e testadas na reaçäo de imunofluoresceína e testadas na reaçäo de imunofluorescência para a detecçäo de anticorpos anti-T. gondii, no diagnóstico da toxoplasmose aguda. Neste estudo tentou-se encontrar reagentes alternativos para conjugados fluorescentes anti-IgM humano (CFAIgMH), que com freqüência contém anticorpos antitoxoplasma, como contaminantes, devido às infecçöes naturais por T. gondii, entre os animais utilizados para imunizaçäo. Conjugados fluorescentes de lectina de lentilha (CFL) (Lens culinaris) forneceram resultados satisfatórios. Avaliaçäo do CFL efetuada em total de 179 amostras de soros de pacientes com toxoplasmose aguda e crônica, com infecçöes näo relacionadas e de indivíduos sadios, mostrou valores altos nos índices de eficiência relativa, co-positividade e co-negatividade, respectivamente de 0,989, 0,969 e 1,000, em relaçäo ao CFFAIgMH convencional. Além disso, três partidas de CFL preparadas sucessivamente forneceram resultados reprodutíveis. A vantagem de se empregar o LFC como reagente alternativo no diagnóstico sorológico da toxoplasmose aguda consiste nos aspectos práticos da sua preparaçäo

Diagrama de verificacion para evaluar reactivos de hemaglutinacion usados en el diagnostico de la enfermedad de Chagas / A control chart method for evaluating hemagglutination reagent used in Chagas' disease diagnosis

Se describe la tecnica del diagrama de verificacion, menos complicada y mas apta que la tecnica de analisis secuencial para evaluar lotes pequenos de reactivo. En este método se necesitan un reactivo de referencia, un conjunto de alrededor de 20 muestras de suero y un limite establecido de la varianza que, cuando es sobrepasado, determina el rechazo del lote puesto a prueba. La mitad de las muestras de suero deben ser reactivas con respecto al antigeno de Trypanosoma cruzi y la otra mitad deben ser no reactivas; los sueros reactivos tienen que ser utiles en el sentido que su respuesta ante un reactivo de buena calidad (como el de referencia) es distinta de la que manifiestan ante un mal reactivo. Con este procedimiento, el reactivo de referencia y el reactivo que se quiere evaluar se ponen a prueba con el conjunto de muestras de suero; se observan las diferencias entre los titulos obtenidos con los dos reactivos y se calcula la desviacion estandar promedio. Cuando esta es inferior al limite de verificacion previamente establecido, el lote de reactivo es aceptado; si supera el limite, se rechaza el lote. La experiencia del Laboratorio de Inmunologia del Instituto de Medicina Tropical de Sao Paulo, Brasil, ha demostrado que los sueros que producen titulos relativamente altos pueden usarse para detectar reactivos de mala calidad, y que es eficaz la conservacion de los sueros en un volumen igual de glicerina, almacenados a -20 °C