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.

Diversity of somatic coliphages in coastal regions with different levels of anthropogenic activity in São Paulo State, Brazil.

Bacteriophages are the most abundant and genetically diverse viruses on Earth, with complex ecology in both quantitative and qualitative terms. Somatic coliphages (SC) have been reported to be good indicators of fecal pollution in seawater. This study focused on determining the concentration of SC and their diversity by electron microscopy of seawater, plankton, and bivalve samples collected at three coastal regions in São Paulo, Brazil. The SC counts varied from <1 to 3.4 × 10(3) PFU/100 ml in seawater (73 samples tested), from <1 to 4.7 × 10(2) PFU/g in plankton (46 samples tested), and from <1 to 2.2 × 10(1) PFU/g in bivalves (11 samples tested). In seawater samples, a relationship between the thermotolerant coliforms and Escherichia coli and SC was observed at the three regions (P = 0.0001) according to the anthropogenic activities present at each region. However, SC were found in plankton samples from three regions: Baixada Santista (17/20), Canal de São Sebastião (6/14), and Ubatuba (3/12). In seawater samples collected from Baixada Santista, four morphotypes were observed: A1 (4.5%), B1 (50%), C1 (36.4%), and D1 (9.1%). One coliphage, Siphoviridae type T1, had the longest tail: between 939 and 995 nm. In plankton samples, Siphoviridae (65.8%), Podoviridae (15.8%), Microviridae (15.8%), and Myoviridae (2.6%) were found. In bivalves, only the morphotype B1 was observed. These SC were associated with enteric hosts: enterobacteria, E. coli, Proteus, Salmonella, and Yersinia. Baixada Santista is an area containing a high level of fecal pollution compared to those in the Canal de São Sebastião and Ubatuba. This is the first report of coliphage diversity in seawater, plankton, and bivalve samples collected from São Paulo coastal regions. A better characterization of SC diversity in coastal environments will help with the management and evaluation of the microbiological risks for recreation, seafood cultivation, and consumption.

Improvement of the slide hemagglutination test for rapid Chagas' disease screening in epidemiological surveys.

A slide hemagglutination test, here called SHAT, which is practical and economical for seroepidemiological surveys was standardized. This is an improved modification of the rapid hemagglutination test (RHA) which utilizes a short-lived reagent prepared with fresh blood cells. The reagent and conditions of the test were considerably modified and, most importantly, an alkaline-solubilized Trypanosoma cruzi epimastigote antigen reagent is proposed. The stability of the SHAT reagent was at least one year at 4 degrees C, in an appropriate liquid suspension. The SHAT was applied to 71 serum samples from patients with Chagas' disease and from 235 clinically healthy blood donors. Sensitivity, specificity and positive and negative predictive values for the selected cutoff titer corresponding to 1:4 dilution were 0.972 (0.903-0.992), 0.983 (0.957-0.993), 0.945 (0.867-0.979) and 0.991 (0.969-0.998), respectively. These values were comparable to those found for the RHA, immunofluorescence (IFT), indirect hemagglutination (IHAT) and complement fixation (CFT) tests. These data suggest that the SHAT should be useful for seroepidemiological surveys conducted at public health laboratories in developing countries.

Improvement of the slide hemagglutination test for rapid Chagas' disease screening in epidemiological surveys

A slide hemagglutination test, here called SHAT, which is practical and economical for seroepidemiological surveys was standardized. This is an improved modification of the rapid hemagglutination test (RHA) which utilizes a short-lived reagent prepared with fresh blood cells. The reagent and conditions of the test were considerably modified and, most importantly, an alkaline-solubilized Trypanosoma cruzi epimastigote antigen reagent is proposed. The stability of the SHAT reagent was at least one year at 4 degrees Celsius, in an appropriate liquid suspension. The SHAT was applied to 71 serum samples from patients with Chagas' disease and from 235 clinically healthy blood donors. Sensitivity, specificity and positive and negative predictive values for the selected cutoff titer corresponding to 1:4 dilution were 0.972 (0.903-0.992)9 O.983 (O.957-0.993) 0.945 (O.867-0.979) and O.991 (O.969-0.998), respectively. These values were comparable to those found for the RHA, immunofluorescence (IFT), indirect hemagglutination (IHAT) and complement fixation (CFT) tests. These data suggest that the SHAT should be useful for seroepidemiological surveys conducted at public health laboratories in developing countries.