Influence of specific treatment on the morbidity of schistosomiasis mansoni in an endemic area of Minas Gerais, Brazil

The authors describe the evolution of schistosomiasis mansoni in inhabitants of Capitão Andrade, Minas Gerais, Brazil, from 1973 to 1994. The prevalence of infection was 60.8% in 1973, 36.2% in 1984, and 27.3% in 1994. The evolution of the clinical forms of the disease in this group was as follows: unchanged in 76.7%, clinical progression in 8.4% and clinical regression in 14.9%. The reduction of the prevalence and severity of Schistosoma mansoni infection over the 21 years period, can be attributed to treatment of infected subjects performed in the area and to the installation of piped water in their dwellings.

Comparison between specific and multiplex reverse transcription-polymerase chain reaction for detection of hepatitis A virus, poliovirus and rotavirus in experimentally seeded oysters

Outbreaks of gastroenteritis have occurred among consumers of raw or undercooked shellfish harvested from faecally polluted waters. A multiplex reverse transcription-polymerase chain reaction (RT-PCR) was applied for the simultaneous detection of hepatitis A virus (HAV), poliovirus (PV) and simian rotavirus (RV-SA11) and compared with specific primers for each genome sequence. Three amplified DNA products representing HAV (192 bp), PV (394 bp) and RV (278 bp) were identified when positive controls were used. However, when tested on experimentally contaminated raw oysters, this method was not able to detect the three viruses simultaneously. This is probably due to the low concentration of viral RNAs present in oyster extract which were partially lost during the extracts preparation.

Detection of Cryptosporidium - specific coproantigen in human immunodeficiency virus/acquired immunodeficiency syndrome patients by using a commercially available immunoenzymatic assay

The aim of this study was to verify the occurrence of Cryptosporidium infection in 52 human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients (group 1) and 38 clinically healthy individuals (group 2) by using enzyme immunoassay (EIA). All fecal samples collected were submitted to the Baermann, Lutz, and Ritchie methods, the Safranin/Methylene Blue, and Weber's chromotrope modified Trichrome staining techniques, and EIA. In group 1, parasitological staining techniques and EIA were both positive for Cryptosporidium sp. infection in 3/52 (5.8%) samples and both negative in 45/52 (86.5%) samples, while 4/52 (7.7%) samples were positive in EIA and negative in parasitological staining techniques. Concerning group 2, all samples were negative by EIA and microscopy for Cryptosporidium infection. In conclusion, EIA may be an alternative method for detecting Cryptosporidium-specific coproantigen in HIV/AIDS patients.

Stage-specific activity of potential antimalarial compounds measured in vitro by flow cytometry in comparison to optical microscopy and hypoxanthine uptake

The evaluation of new antimalarial agents using older methods of monitoring sensitivity to antimalarial drugs are laborious and poorly suited to discriminate stage-specific activity. We used flow cytometry to study the effect of established antimalarial compounds, cysteine protease inhibitors, and a quinolone against asexual stages of Plasmodium falciparum. Cultured P. falciparum parasites were treated for 48 h with different drug concentrations and the parasitemia was determined by flow cytometry methods after DNA staining with propidium iodide. P. falciparum erythrocytic life cycle stages were readily distinguished by flow cytometry. Activities of established and new antimalarial compounds measured by flow cytometry were equivalent to results obtained with microscopy and metabolite uptake assays. The antimalarial activity of all compounds was higher against P. falciparum trophozoite stages. Advantages of flow cytometry analysis over traditional assays included higher throughput for data collection, insight into the stage-specificity of antimalarial activity avoiding use of radioactive isotopes.