Pre-ozonation of source water: Assessment of efficacy against Giardia duodenalis cysts and effects on natural organic matter.

The protozoan Giardia duodenalis is one of the parasites of primary concern in drinking water treatment plants, due to its resistance to chlorination. Another matter of concern regarding chlorination of drinking water is the formation of disinfection by-products in the presence of precursors such as natural organic matter (NOM). In this study, the effects of ozonation (5 mg L-1) on G. duodenalis cysts in raw surface water from a drinking water treatment plant were evaluated, and the presence and alteration of NOM were assessed, as an indicative of the potential to prevent total organic halogen (TOX) formation during post-chlorination. Following ozone treatment, the presence of damaged cysts was observed by direct immunofluorescence assay (IFA) and confirmed by the molecular approach propidium monoazide-polymerase chain reaction (PMA-PCR). Using an animal model, analysis of the intestinal tissues revealed that 80% of the animals inoculated with ozonated water were positive for trophozoites. This study shows that analysis of intestinal fragments is imperative to accurately assess animal infection following inoculation of treated cysts. More importantly, considering the low infective dose of Giardia cysts in susceptible hosts, an ozone dosage usually applied in drinking water treatment plants did not completely inactivate G. duodenalis cysts in surface water. Nonetheless, the results suggest that competitive reactions with NOM have occurred, and the applied ozone dosage has proven useful to remove NOM reactivity, and thus prevent halogenated DBP formation during post-chlorination.

Enterocytozoon bieneusi detected by molecular methods in raw sewage and treated effluent from a combined system in Brazil

BACKGROUND Enterocytozoon bieneusi are the most common microsporidia associated with different clinical manifestations such as diarrhoea, respiratory tract inflammation and acalculous cholecystitis, especially in immunocompromised patients. Infection usually occurs by ingestion of food and water contaminated with spores, but can also result from direct contact with spores through broken skin, eye lesions, and sexual transmission, depending on the microsporidian species. Although there are reports of E. bieneusi found in humans and animals in Brazil, there are no published studies of environmental samples examined by molecular methods. OBJECTIVES The purpose of this study was to verify the presence of E. bieneusi in raw sewage and treated effluent from a combined system by molecular methods. METHODS Raw sewage and treated effluent samples collected from a combined system were analysed for the presence of E. bieneusi using the internal transcriber spacer (ITS) region of E. bieneusi by nested polymerase chain reaction. FINDINGS The analysis revealed E. bieneusi presence and a novel genotype (EbRB) in one raw sewage sample and one treated effluent. MAIN CONCLUSIONS The presence of E. bieneusi in final effluent indicates that the combined system may not remove microsporidian spores. This study is the first report of E. bieneusi in environmental samples in Brazil.

Toxoplasma-SPECIFIC IgG SUBCLASS ANTIBODY RESPONSE IN CEREBROSPINAL FLUID SAMPLES FROM PATIENTS WITH CEREBRAL TOXOPLASMOSIS.

Cerebral toxoplasmosis can be highly debilitating and occasionally fatal in persons with immune system deficiencies. In this study, we evaluated the Toxoplasma gondii-specific IgG subclass antibody response in 19 cerebrospinal fluid (CSF) samples from patients with cerebral toxoplasmosis who had a positive IgG anti-T. gondii ELISA standardized with a cyst antigen preparation. There were no significant differences between the rates of positivity and the antibody concentrations (arithmetic means of the ELISA absorbances, MEA) for IgG1 and IgG2, but the rates of positivity and MEA values for these two IgG subclasses were significantly higher than those for IgG3 and IgG4. The marked IgG2 response in CSF from patients with cerebral toxoplasmosis merits further investigation.

Molecular characterization of intestinal protozoa in two poor communities in the State of São Paulo, Brazil.

BACKGROUND: Several species of protozoa cause acute or chronic gastroenteritis in humans, worldwide. The burden of disease is particularly high among children living in developing areas of the world, where transmission is favored by lower hygienic standards and scarce availability of safe water. However, asymptomatic infection and polyparasitism are also commonly observed in poor settings. Here, we investigated the prevalence of intestinal protozoa in two small fishing villages, Porto Said (PS) and Santa Maria da Serra (SM), situated along the river Tietê in the State of São Paolo, Brazil. The villages lack basic public infrastructure and services, such as roads, public water supply, electricity and public health services. METHODS: Multiple fecal samples were collected from 88 individuals in PS and from 38 individuals in SM, who were asymptomatic at the time of sampling and had no recent history of diarrheal disease. To gain insights into potential transmission routes, 49 dog fecal samples (38 from PS and 11 from SM) and 28 river water samples were also collected. All samples were tested by microscopy and PCR was used to genotype Giardia duodenalis, Blastocystis sp., Dientamoeba fragilis and Cryptosporidium spp. RESULTS: By molecular methods, the most common human parasite was Blastocystis sp. (prevalence, 45% in PS and 71% in SM), followed by D. fragilis (13.6% in PS, and 18.4% in SM) and G. duodenalis (18.2% in PS and 7.9% in SM); Cryptosporidium spp. were not detected. Sequence analysis revealed large genetic variation among Blastocystis samples, with subtypes (STs) 1 and 3 being predominant, and with the notable absence of ST4. Among G. duodenalis samples, assemblages A and B were detected in humans, whereas assemblages A, C and D were found in dogs. Finally, all D. fragilis samples from humans were genotype 1. A single dog was found infected with Cryptosporidium canis. River water samples were negative for the investigated parasites. CONCLUSIONS: This study showed a high carriage of intestinal parasites in asymptomatic individuals from two poor Brazilian villages, and highlighted a large genetic variability of Blastocystis spp. and G. duodenalis.

Fluorescence decay of dyed protozoa: differences between stressed and non-stressed cysts.

Several series of tests have shown that fresh, intact samples of Giardia duodenalis and Cryptosporidium parvum (oo)cysts are not marked by fluorescent probes such as carboxyfluorcein-succinimidyl-diacetate-ester (CFDA-SE), C12-resazurin and SYTOX® Green, probably because of their robust cell walls. These dyes fail to indicate the viability of such protozoa and allow negative responses to be recorded from living and infectious samples. Cryptosporidium parvum showed stronger isolation from chemicals, with living oocysts remaining unstained by the probe for up to 90 days after extraction. However, in further fluorescence decay (FD) experiments run with G. duodenalis samples stained using CFDA-SE (comprising living, non-stressed but aged cysts, heat-killed samples and UV-C-stressed samples) each showed a different FD decay profile, here studied in seven series of tests of five replicates each. The FD profiles were fitted by double-exponential decay kinetics, with the decay constant k2 being five times higher than k1. This FD procedure is fast and can be easily reproduced in 10 steps, taking ~ 1 h of laboratory work for already purified samples.

Parasitologia ambiental: métodos de concentração e detecção de Cryptosporidium spp. e Giardia spp. em amostras de água / Environmental parasitology: methods of concentration and detection of Cryptosporidium spp. and Giardia spp. in water samples

A transmissão de protozoários patogênicos pela água é um dos mais relevantes problemas de saúde pública na atualidade. Numerosos surtos epidêmicos causados pelos protozoários Giardia e Cryptosporidium ocorreram ao redor do mundo em passado recente. Entretanto, os métodos utilizados para a detecção de cistos e oocistos em amostras de água são influenciados porcaracterísticas físico-químicas da matriz de água, como a turbidez. Esta revisão apresenta uma análise crítica das diferentes metodologias de concentração de cistos de Giardia e de oocistos de Cryptosporidium em amostras de águas destinadas ao consumo humano. A implantação domonitoramento desses protozoários é uma necessidade no Brasil dada a recente revisão da Portarianúmero 518 do Ministério da Saúde.

Avaliação da performance de metodologias de detecção de Cryptosporidium spp. e Giardia spp. em água destinada ao consumo humano, para o atendimento às demandas da Vigilância em Saúde Ambiental no Brasil / Performance evaluation of different methodologies for detection of Cryptosporidium spp. and Giardia spp. in water for human consumption to meet the demands of the Environmental Health Surveillance in Brazil

Objetivo: avaliar a performance de três protocolos de concentração de cistos e oocistos em amostras de água bruta de rios brasileiros. Métodos: os protocolos estudados foram precipitação química, filtração em membranas de 47mm de diâmetro e 3μm de porosidade nominal e filtração com o sistema Filta-Max®. Amostras de água bruta coletadas de rios nos estados de São Paulo e Minas Gerais foram analisadas após contaminação artificial. Os resultados de precisão inicial e recuperação de organismos marcados (Color-Seed®) foram comparados com os critérios da Agencia de Proteção Ambiental dos Estados Unidos da Améri¬ca (USEPA). Resultados: Nos ensaios de precisão inicial para cistos de Giardia, a filtração em membranas e com Filta-Max® atingiram os critérios da USEPA para recuperação de cistos. Para Cryptosporidium, somente o procedimento com Filta-Max® alcançou os critérios. Conclusão: o sistema Filta-Max® foi o único método que atingiu todos os critérios para identificação de Cryptosporidium e Giardia em água.

Objective: this study aimed to evaluate three different concentration protocols of cysts and oocysts in raw water samples in Brazilian rivers. Methods: the protocols studied were chemical precipitation, filtration in membranes of 47mm of diameter versus nominal porosity of 3µm and filtration using Filta-Max® system. The raw water samples collectedfrom rivers in the states of São Paulo andMinas Gerais were analyzed after being seeded with Color-Seed®. The results of initial precision using filtration in membranes and recovery of Color-Seed® organisms were compared to the acceptance criteria established by the United States Environmental Protection Agency (USEPA). Results: The study of initial precision to Giardia using filtration in membranes and recovery of Color-Seed® met the USEPA criteria; for Cryptosporidium only the Filta-Max® achieved the established criteria. Conclusion: Filta-Max® system showed to be the only method that achieved all the performance criteria for identification of Giardia and Cryptosporidium in water.

A parasitological survey of natural water springs and inhabitants of a tourist city in southeastern Brazil.

The goals of this study were to investigate the occurrence of Cryptosporidium oocysts and Giardia cysts in main springs of Campos do Jordão, an important tourist city, in Brazil and to gather the largest amount of parasitological data from autochthonous population that live in rural areas of this city. The membrane filtration technique followed by direct immunofluorescence assay was employed for concentration and visualization of waterborne protozoa. In the period between June 2003 and May 2004, the presence of at least one pathogenic protozoa was detected in 25.0% (3/12) of the springs studied, with mean concentrations ranging from 0.2 to 0.3 Cryptosporidium sp. oocysts and 0.07 to 0.1 Giardia sp. cysts/L. The coproparasitological investigation conducted in dwellers from two rural communities from this city revealed that 49.2% (91/185) of people had intestinal parasites. Among pathogenic protozoa, Cryptosporidium was the most prevalent species (8.1%) followed by Giardia duodenalis (5.9%), Entamoeba histolytica/Entamoeba dispar (2.7%), and Blastocystis hominis (2.2%). The most prevalent geohelminths were Ascaris lumbricoides (14.9%) and Trichuris trichiura (9.7%). This study demonstrated the contamination and the distribution of intestinal parasites, especially Cryptosporidium and Giardia species, in different springs of an important tourist city in Brazil, highlighting the need of monitoring natural water sources. The high prevalence of intestinal parasitosis detected in some specific populations of this city may function as a link of transmission of different intestinal parasitosis due to soil and water contamination, contributing to the maintenance of parasite life cycles. Therefore, the inclusion of consistent public health interventions with measures that include the protection of springs, the installation of minimum health infrastructure, and primary education of the population are widely necessary, aiming the control and prevention of parasite infections.

Meningioma intramedular cervical: relato de caso e revisão da literatura / Intramedullary cervical meningioma: a case report and literature review

Os meningiomas estão entre os tumores benignos mais comuns do canal espinhal, em adultos, encontrados, predominantemente, nos segmentos torácicos. Segundo a literatura, a ocorrência de um meningioma intramedular cervical é muito rara, com apenas oito trabalhos científicos relatados até o momento. Apresentaremos o nono relato de caso ? talvez o primeiro relato publicado na literatura médica brasileira ? e revisaremos os estudos anteriores. Paciente, de 40 anos de idade, iniciou com sintomas de fraqueza na mão direita e dores cervicais que se agravavam durante a noite. A ressonância magnética revelou lesão intramedular extensa cervical. A paciente foi submetida somente à biópsia, por causa de dificuldades na ressecção, sendo depois proposta radioterapia. O tumor teve uma discreta redução, a paciente permaneceu sem piora dos sinais e sintomas durante os oito anos de evolução. Embora muito raros, meningiomas intramedulares cervicais existem e devem estar no diagnóstico diferencial de tumores nessa localização. O principal tratamento dessas lesões, de acordo com relatos anteriores, é a cirurgia, com bons resultados.

Meningiomas are among the most common benign tumours of the spinal canal in adults, found predominantly in the thoracic segments. According to the literature, the occurrence of an intramedullary cervical meningioma is very rare, with only eight scientific papers reported in the literature so far. We present the ninth case report ? probably the first reported in the Brazilian medical literature ? and review the previous reports. 40-year-old patient, who started the symptoms with weakness in her right hand and neck pain that worsened at night. The MRI revealed extensive intramedullary cervical lesion. The patient underwent biopsy only and, then, underwent radiotherapy. The tumor had a slight reduction and the patient remained without worsening of signs and symptoms during the eight years of evolution. Although very rare, intramedullary cervical meningiomas should be in the differential diagnosis of tumors of this location. The main treatment of these lesions, according to previous reports, is surgery with excellent results.