RESUMO
BACKGROUND: Cyclosporiasis has a marked seasonality. Few community-based studies have addressed this issue and there are no reports from Venezuela. A study was conducted to determine the seasonal variation of infection in a community from Falcon State, Venezuela. METHODS: A sample of 732 individuals was collected for 1 y. Stools were examined with modified Ziehl-Neelsen carbolfuchsin staining of ethyl acetate-formalin concentrates and ultraviolet epiflorescence of wet mounts. RESULTS: Cyclospora prevalence was 9.9% (73/732) with monthly variation from 0% to 35.3%. A trend of increased infections coinciding with the rainy time was observed (p<0.001). CONCLUSIONS: Cyclosporiasis is common in this area with high endemicity during the rainy periods.
Assuntos
Cyclospora , Ciclosporíase , Ciclosporíase/epidemiologia , Diarreia/epidemiologia , Fezes , Humanos , Estações do Ano , Venezuela/epidemiologiaRESUMO
The prevalence and importance of Cyclospora cayetanensis as an enteropathogen among 71 patients (22-45 years old) with acquired immunodeficiency syndrome (AIDS) and 132 children with diarrhea (0-12 years old) from Venezuela was assessed retrospectively. Two to three stool samples from each patient attending our parasitology laboratory for parasitologic and medical assistance were examined. For identification of the coccidium, modified Ziehl-Neelsen carbolfuchsin staining of formalin-ether stool concentrates was used, and for other intestinal parasites, iron-hematoxylin-stained smears and formalin-ether concentrates were examined. Cyclospora oocysts were found in seven (9.8%) of 71 AIDS patients and seven (5.3%) of 132 children with diarrhea. Other pathogenic parasites were present in most of the patients (9 of 14, 64.3%) shedding oocysts. Cyclosporiasis predominated in children 2-5 years of age with respect to those < or = one year of age (P < 0.05). The findings suggest that C. cayetanensis is common in diarrheal patients from Venezuela. However, the role of the parasite as the causal agent of diarrhea in these patients is uncertain.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Síndrome da Imunodeficiência Adquirida/complicações , Ciclosporíase/epidemiologia , Diarreia/parasitologia , Adulto , Distribuição por Idade , Criança , Pré-Escolar , Cyclospora , Diarreia/epidemiologia , Diarreia/etiologia , Fezes/parasitologia , Feminino , Humanos , Imunocompetência , Hospedeiro Imunocomprometido , Lactente , Masculino , Pessoa de Meia-Idade , Oócitos , Prevalência , Estudos Retrospectivos , Venezuela/epidemiologiaRESUMO
To determine whether treatment with melatonin (MLT) improves the efficiency of immunization against Venezuelan equine encephalomyelitis (VEE) virus, mice were vaccinated with TC-83 VEE virus and treated daily with MLT (1 or 5 mg/kg) starting 3 days before immunization, until 10 days after. IgM antibody titers were determined at days 7, 14, and 21 post-immunization. IL-10 levels were assayed at day 14 postvaccination. Treatment with MLT increased antibody titers 14 days after the immunization. IL-10 levels also increased with MLT treatment (1 and 5 mg/kg). Mice were challenged with live VEE virus at day 21 postimmunization, and viral titers were plaque assayed in chicken embryo fibroblasts 4 days after the infection. Following this challenge brain virus levels were significantly reduced. The results suggest that MLT treatment enhances the efficiency of mice immunization against VEE virus.
Assuntos
Adjuvantes Imunológicos/farmacologia , Vírus da Encefalite Equina Venezuelana/imunologia , Encefalomielite Equina Venezuelana/prevenção & controle , Imunização , Melatonina/farmacologia , Vacinas Virais/imunologia , Animais , Anticorpos Antivirais/análise , Encéfalo/virologia , Vírus da Encefalite Equina Venezuelana/isolamento & purificação , Encefalomielite Equina Venezuelana/virologia , CamundongosRESUMO
Entamoeba histolytica was redefined to recognize the existence of two morphologically indistinguishable species but genetically distinct: E. histolytica and E. dispar. The former is a pathogen responsible for amebiasis while the latter is a commensal. This redefinition has dramatically changed the understanding of amebiasis and its clinical management.
Assuntos
Entamoeba/classificação , Entamebíase/parasitologia , Animais , Entamoeba/enzimologia , Entamoeba/genética , Entamoeba/isolamento & purificação , Entamoeba histolytica/enzimologia , Entamoeba histolytica/genética , Entamoeba histolytica/fisiologia , Entamebíase/epidemiologia , Saúde Global , Hexoquinase/análise , Humanos , Isoenzimas/análise , Prevalência , Proteínas de Protozoários/análise , Especificidade da Espécie , VenezuelaRESUMO
In mice infected with the Venezuelan equine encephalomyelitis (VEE) virus and exposed to high intensity light (2500 lux) with a 12 h light: 12 h dark photoperiod, a significant increase in the levels of melatonin in the olfactory bulb was observed. The significance of these findings deserves further studies to understand the mechanisms involved in this effect since the olfactory bulbs have been proposed as first portal for VEE virus entry into the CNS. The increase in melatonin content could represent one of the mechanisms of defense against the viral attack.
Assuntos
Encefalomielite Equina Venezuelana/metabolismo , Luz , Melatonina/metabolismo , Bulbo Olfatório/efeitos da radiação , Animais , Ritmo Circadiano , Relação Dose-Resposta à Radiação , Encefalomielite Equina Venezuelana/fisiopatologia , Masculino , Camundongos , Bulbo Olfatório/metabolismo , Bulbo Olfatório/fisiopatologiaRESUMO
A survey of 447 Amerindians aged 1-69 years (mean age, 18.6 +/- 15.8 years) in 3 mountain and 1 lowland communities from Venezuela were studied to determine the seroprevalence of Toxoplasma gondii, the environmental risk factors for the infection, and how the process of acculturation may affect the transmission rate. Serum samples were tested for immunoglobulin G antibodies by a commercial indirect hemagglutination test. The overall prevalence of infection was 49.7% (222 of 447) and ranged 38.2-62.4%. A higher antibody rate was found in the lowland setting as compared with those from the mountain area (P < 0.001). The geometric mean titer in the overall population was 280.3. No age-antibody association was detected in the mountain communities, although a gradual increase in positivity with increasing age (P < 0.01) was observed in the lowland setting, reaching a peak of 83.3% in the oldest group. The results suggest that transmission by infective cat feces may play a predominant role in the spread of infection in this population. This study demonstrates the environmental Toxoplasma infection pressure in this sylvatic population and how transmission rate is facilitated by environmental changes produced by acculturation.
Assuntos
Anticorpos Antiprotozoários/sangue , Indígenas Sul-Americanos , Toxoplasma/imunologia , Toxoplasmose/epidemiologia , Adolescente , Adulto , Idoso , Animais , Criança , Pré-Escolar , Humanos , Imunoglobulina G/sangue , Lactente , Pessoa de Meia-Idade , Prevalência , População Rural , Estudos Soroepidemiológicos , Toxoplasmose/transmissão , Venezuela/epidemiologiaRESUMO
Until recently, only the bovine and human genotypes of Cryptosporidium parvum had been considered to infect man and to be potential pathogens. Lately, symptomatic infections with C. felis, C. meleagridis, and C. parvum-like dog genotype have been described in immunocompetent and immunosuppressed individuals. These findings suggest that zoonotic parasites could also play an important role in Public Health.
Assuntos
Cryptosporidium/patogenicidade , Saúde Pública , Animais , Cryptosporidium/classificação , Humanos , Especificidade da Espécie , VirulênciaRESUMO
Male albino mice immunodepressed after the injection of dexamethasone (DEX) were inoculated intraperitoneally with the Guajira strain of Venezuelan equine encephalomyelitis (VEE) virus. Melatonin (MLT) was administered daily, at a dose of 500 micrograms/kg bodyweight, for 3 days before virus inoculation and 10 days after. Serum levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) were determined in all the experimental groups (control, DEX, DEX + MLT, DEX + VEE, DEX + VEE + MLT, VEE and MLT). At day 6 after the virus inoculation, the survival rate was significantly increased from 0% in group DEX + VEE to 32.5% in the group of immunodepressed infected mice treated with MLT (DEX + VEE + MLT). By day 10 a survival rate of 10% was found in group DEX + VEE + MLT and 0% in group VEE. No alterations in IL-2 serum levels were observed. MLT increased GM-CSF in control and in DEX-treated mice. In the VEE virus-infected mice treated with DEX, serum levels of GM-CSF increased progressively from day 1 to 5 postinoculation. In contrast, the levels of GM-CSF in infected immunodepressed mice treated with MLT decreased significantly from day 1 to 5 postinoculation. At day 5 after viral inoculation, no differences were detected in the cerebral viral titres in groups VEE, DEX + VEE and DEX + MLT + VEE. These results show that MLT does not inhibit VEE viral replication in the brain of immunodepressed mice.
Assuntos
Adjuvantes Imunológicos/uso terapêutico , Encefalomielite Equina Venezuelana/tratamento farmacológico , Terapia de Imunossupressão/efeitos adversos , Melatonina/uso terapêutico , Animais , Dexametasona/imunologia , Encefalomielite Equina Venezuelana/imunologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Interleucina-2/sangue , Masculino , Melatonina/imunologia , Camundongos , Análise de SobrevidaRESUMO
The prevalences of intestinal parasites and intensities of helminth infections were studied in two Amerindian villages in Venezuela. Single stool specimens were collected from 303 individuals from Saimadoyi and 130 from Campo Rosario. Wet mounts, iron-hematoxylin-stained smears, and formalin-ether concentrates were examined for the presence of parasites; modified Ziehl-Neelsen carbol-fuchsin staining of 10% formalin-preserved stool was used to identify Cryptosporidium parvum. Helminth ova counts were made using the standard smear egg count technique. Mixed infections (Campo Rosario = 69.9%, Saimadoyi = 71.6%) were frequent. Overall infection rates with one or more species (Campo Rosario = 79.2%, Saimadoyi = 95.4%; P < 0.01) and with any protozoans (Campo Rosario = 60.8%, Saimadoyi = 72.3%; P < 0.05) were high and predominant (P < 0.05) in Saimadoyi. Cryptosporidiosis was identified in 38 subjects (8.8%) in both villages; 60.6% were asymptomatic carriers. The mean egg counts of helminths were heavier in Campo Rosario (P < 0.05), which was probably due to the drastic reduction of their lands along with their low standard of living. This study documents the change of intestinal parasitism pattern and deterioration of the health of Amerindians by the process of acculturation.