RESUMO
We conducted a prospective, longitudinal study in a cohort of 36 Peace Corps volunteers (PCVs) in Guatemala to study the incidence and natural history of intestinal parasitic infections during the PCVs' >2-year overseas stay. PCVs collected stool specimens at least monthly and when ill with gastrointestinal symptoms. Of the 1,168 specimens tested, 453 (38.8%) were positive for at least one parasite and 48 (4.1%) were positive for a pathogenic parasite. A median interval of 187 days (range, 14 to 752 days) elapsed before the first documented parasitic infection, and the median intervals from arrival until subsequent infections (e.g., second or third) were >300 days. The PCVs had 116 episodes of infection with 11 parasites, including up to 4 episodes per PCV with specific nonpathogens and Blastocystis hominis. The incidence, in episodes per 100 person-years, was highest for B. hominis (65), followed by Entamoeba coli (31), Cryptosporidium parvum (17), and Entamoeba hartmanni (17). The PCVs' B. hominis episodes lasted 6,809 person-days (28.7% of the 23,689 person-days in the study), the E. coli episodes lasted 2,055 person-days (8.7%), and each of the other types of episodes lasted <2% of the person-days in the study. Gastrointestinal symptoms were somewhat more common and more persistent, but not significantly so, in association with pathogen episodes than with B. hominis and nonpathogen episodes. Although infections with pathogenic parasites could account for only a minority of the PCVs' diarrheal episodes, the continued acquisition of parasitic infections throughout the PCVs' >2-year stay in Guatemala suggests that PCVs repeatedly had fecal exposures and thus were at risk for infections with both parasitic and nonparasitic pathogens throughout their overseas service.
Assuntos
Órgãos Governamentais , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Intestinos/parasitologia , Infecções por Protozoários/epidemiologia , Voluntários , Adulto , Animais , Blastocystis hominis/isolamento & purificação , Estudos de Coortes , Cryptosporidium parvum/isolamento & purificação , Diarreia/epidemiologia , Diarreia/parasitologia , Entamoeba/isolamento & purificação , Fezes/parasitologia , Feminino , Guatemala/epidemiologia , Humanos , Incidência , Estudos Longitudinais , Masculino , Estudos Prospectivos , Infecções por Protozoários/parasitologia , Estudos SoroepidemiológicosRESUMO
Formalin and mercuric chloride-based low-viscosity polyvinyl alcohol (LV-PVA) are widely used by most diagnostic parasitology laboratories for preservation of helminth eggs and protozoan cysts and trophozoites in fecal specimens. Concerns about the toxicity of formalin and the difficulty of disposal of LV-PVA are powerful incentives to use alternate preservatives. Such alternatives have been marketed by several companies and are often presented as one-vial, non-mercuric chloride fixatives that aim at performing the same role as formalin and PVA combined. We compared five, one-vial commercial preservatives, two from Meridian Diagnostics, Inc. (Ecofix and sodium acetate-acetic acid-formalin), and one each from Scientific Device Laboratories, Inc. (Parasafe), Alpha Tec Systems, Inc. (Proto-fix), and Streck Laboratories, Inc. (STF), with 10% formalin and LV-PVA. Fecal specimens obtained from patients in a Brazilian hospital were aliquoted within 12 h of collection into the seven preservatives mentioned above and were processed after 1 month at the Centers for Disease Control and Prevention. Direct and concentrated permanent smears as well as concentrates for 20 positive specimens (a total of 259 processed samples) were prepared, stained according to the manufacturers' instructions, examined, and graded. Positive specimens contained one or more parasites with stages consisting of eggs, larvae, cysts, and a few trophozoites of Giardia intestinalis. Criteria for assessment of the preservatives included the quality of the diagnostic characteristics of helminth eggs, protozoan cysts, and trophozoites, ease of use, and cost. Acceptable alternatives to formalin for wet preparations were found. Ecofix was found to be comparable to the traditional "gold standard" LV-PVA for the visualization of protozoa in permanent stained smears. This study suggests that more acceptable alternatives to the traditional formalin and LV-PVA exist.
Assuntos
Eucariotos/isolamento & purificação , Fezes/parasitologia , Helmintos/isolamento & purificação , Animais , Brasil , Eucariotos/citologia , Formaldeído , Helmintos/citologia , Humanos , Cloreto de Mercúrio , Contagem de Ovos de Parasitas , Álcool de Polivinil , Manejo de Espécimes/métodosRESUMO
In Bolivia, few data are available to guide empiric therapy for bloody diarrhea. A study was conducted between December 1994 and April 1995 to identify organisms causing bloody diarrhea in Bolivian children. Rectal swabs from children <5 years old with bloody diarrhea were examined for Salmonella, Shigella, and Campylobacter organisms; fecal specimens were examined for Entamoeba histolytica. A bacterial pathogen was identified in specimens from 55 patients (41%). Shigella organisms were found in 39 specimens (29%); 37 isolates (95%) were resistant to ampicillin, 35 (90%) to trimethoprim-sulfamethoxazole, and 24 (62%) to chloramphenicol, but all were susceptible to nalidixic acid. Only 1 of 133 stool specimens contained E. histolytica trophozoites. Multidrug-resistant Shigella species are a frequent cause of bloody diarrhea in Bolivian children; E. histolytica is uncommon. Clinical predictors described in this study may help identify patients most likely to have Shigella infection. Laboratory surveillance is essential to monitor antimicrobial resistance and guide empiric treatment.
Assuntos
Antibacterianos/farmacologia , Diarreia/microbiologia , Disenteria Bacilar/tratamento farmacológico , Shigella/efeitos dos fármacos , Shigella/isolamento & purificação , Animais , Antibacterianos/uso terapêutico , Bolívia , Campylobacter/isolamento & purificação , Infecções por Campylobacter/tratamento farmacológico , Infecções por Campylobacter/microbiologia , Pré-Escolar , Diarreia/tratamento farmacológico , Diarreia/parasitologia , Resistência Microbiana a Medicamentos , Resistência a Múltiplos Medicamentos , Disenteria Amebiana/tratamento farmacológico , Disenteria Amebiana/parasitologia , Disenteria Bacilar/microbiologia , Empirismo , Entamoeba histolytica/isolamento & purificação , Fezes/parasitologia , Feminino , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Salmonella/isolamento & purificação , Infecções por Salmonella/tratamento farmacológico , Infecções por Salmonella/microbiologiaRESUMO
To determine the frequency of the parasitic pathogens in human immunodeficiency virus (HIV)-infected patients in a developing world setting, 295 stool specimens were examined from 166 HIV-positive patients (49% with AIDS) at São José Hospital, Fortaleza, Brazil, from September 1990 to March 1992. Significantly more patients with diarrhea (85%) than without (66%) had AIDS or AIDS-related complex (ARC) (P < .005). Of the potential parasitic causes of diarrhea, only Cryptosporidium parvum and microsporidia were significantly associated with diarrheal disease. Infections with C. parvum, but not microsporidia, were associated with the rainy season (P < .005). Thus, C. parvum and microsporidia are the most common intestinal parasites associated with diarrhea in an HIV-infected population in Brazil and are associated with advanced HIV disease. The association of C. parvum infections with the rainy season suggests that contaminated water may be important in its transmission; however, the source of human microsporidia requires further investigation.
Assuntos
Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Criptosporidiose/epidemiologia , Cryptosporidium parvum/isolamento & purificação , Diarreia/epidemiologia , Microsporidiose/epidemiologia , Adolescente , Adulto , Idoso , Animais , Brasil/epidemiologia , Criança , Pré-Escolar , Fezes/parasitologia , Feminino , Humanos , Lactente , Masculino , Microsporídios/isolamento & purificação , Pessoa de Meia-Idade , Variações Dependentes do Observador , Chuva , Estudos Retrospectivos , Fatores de Risco , Estações do AnoRESUMO
To assess the role of parasites in causing diarrhea in Peace Corps volunteers in Guatemala, 115 stool specimens from a case-control investigation (48 case [diarrhea] and 26 control episodes) were examined. A potentially pathogenic protozoan that could account for diarrheal illness was found for only 12% of the case episodes.