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Query: UMLS:C0017536 (giardiasis)
 1,714 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Major waterborne cryptosporidiosis and giardiasis outbreaks associated with contaminated drinking water have been linked to evidence of suboptimal treatment. Cryptosporidium parvum oocysts are particularly more resistant than Giardia lamblia cysts to removal and inactivation by conventional water treatment (coagulation, sedimentation, filtration and chlorine disinfection); therefore, extensive research has been focused on the optimization of treatment processes and application of new technologies to reduce concentrations of viable/infectious oocysts to a level that prevents disease. The majority of the data on the performance of treatment processes to remove cysts and oocysts from drinking water have been obtained from pilot-tests, with a few studies performed in full-scale conventional water treatment plants. These studies have demonstrated that protozoan cyst removal throughout all stages of the conventional treatment is largely influenced by the effectiveness of coagulation pretreatment, which along with clarification constitutes the first treatment barrier against protozoan breakthrough. Physical removal of waterborne Crytosporidium oocysts and Giardia cysts is ultimately achieved by properly functioning conventional filters, providing that effective pretreatment of the water is applied. Disinfection by chemical or physical methods is finally required to inactivate/remove the infectious life stages of these organisms. The effectiveness of conventional (chlorination) and alternative (chlorine dioxide, ozonation and ultra violet [UV] irradiation) disinfection procedures for inactivation of Cryptosporidium has been the focus of much research due to the recalcitrant nature of waterborne oocysts to disinfectants. This paper provides technical information on conventional and alternative drinking water treatment technologies for removal and inactivation of the protozoan parasites Cryptosporidium and Giardia.
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PMID:Drinking water treatment processes for removal of Cryptosporidium and Giardia. 1556 86

T lymphocyte-mediated pathogenesis is common to a variety of enteropathies, including giardiasis, cryptosporidiosis, bacterial enteritis, celiac's disease, food anaphylaxis, and Crohn's disease. In giardiasis as well as in these other disorders, a diffuse loss of microvillous brush border, combined or not with villus atrophy, is responsible for disaccharidase insufficiencies and malabsorption of electrolytes, nutrients, and water, which ultimately cause diarrheal symptoms. Other mucosal changes may include crypt hyperplasia and increased infiltration of intra-epithelial lymphocytes. Recent studies using models of giardiasis have shed new light on the immune regulation of these abnormalities. Indeed, experiments using an athymic mouse model of infection have found that these epithelial injuries were T cell-dependent. Findings from further research indicate that that the loss of brush border surface area, reduced disaccharidase activities, and increase crypt-villus ratios are mediated by CD8+ T cells, whereas both CD8+ and CD4+ small mesenteric lymph node T cells regulate the influx of intra-epithelial lymphocytes. Future investigations need to characterize the CD8+ T cell signaling cascades that ultimately lead to epithelial injury and malfunction in giardiasis and other malabsorptive disorders of the intestine.
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PMID:Immunopathology of giardiasis: the role of lymphocytes in intestinal epithelial injury and malfunction. 1596 21

Molecular biology has provided insights into the taxonomy and epidemiology of Cryptosporidium and Giardia, which are major causes of protozoal diarrhoea in humans worldwide. For both genera, previously unrecognized differences in disease, symptomatology, zoonotic potential, risk factors and environmental contamination have been identified using molecular tools that are appropriate for species, genotype and subtype analysis. In this article, to improve understanding of the epidemiology of cryptosporidiosis and giardiasis, we consider specific requirements for the development of more-effective molecular identification and genotyping systems that should be applicable to both clinical and environmental samples.
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PMID:Unravelling Cryptosporidium and Giardia epidemiology. 1604 84

This report addresses Cryptosporidium, Giardia, Cyclospora, and more briefly, Toxoplasma as the main parasitic protozoa of concern to food production worldwide. Other parasitic protozoa may be spread in food or water but are not considered as great a risk to food manufacture. The protozoan parasites Cryptosporidium, Giardia, and Cyclospora have proven potential to cause waterborne and foodborne disease. Toxoplasma gondii has been considered a risk in specific cases, but humans are not its primary host. Cryptosporidium and Giardia are widespread in the environment, particularly the aquatic environment, and major outbreaks of cryptosporidiosis and giardiasis have occurred as a result of contaminated drinking water. Large outbreaks of waterborne cyclosporiasis have not been identified. Cryptosporidium, Giardia, and Cyclospora have potential significance in the preparation and consumption of fresh produce and in catering practice, in which ready-to-eat foods may be served that have not received heat treatment. None of the three organisms Cryptosporidium, Giardia, and Cyclospora has been shown to be a problem for heat processed food or tap water that has undergone appropriate treatment at a water treatment works. All three are sensitive to standard pasteurisation techniques. Although humans are not a primary host for T. gondii, the potential exists for both waterborne and foodborne toxoplasmosis. Parasitic protozoa do not multiply in foods, but they may survive in or on moist foods for months in cool, damp environments. Their ecology makes control of these parasites difficult. For general control of parasitic protozoa in the food chain, the following steps are necessary: - Follow good hygienic practice in food service and catering industries.- Minimise dissemination of cysts and oocysts in the farming environment and via human waste management.- Include these microorganisms in Hazard Analysis Critical Control Point (HACCP) plans of water suppliers, industries or sectors that use fresh produce, and operations in which contaminated process or ingredient water could end up in the product (e.g., where water supplies may become contaminated).
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PMID:Foodborne protozoan parasites. 1608 23

A total of 1,885 blood and stool samples of four main protozoan parasitic infections were retrospectively reviewed from January, 2000 to April, 2004. Eleven of the 1,350 stool samples were shown positive for Cryptosporidium and Giardia infections; one of the 5 cases was clinically diagnosed as gastrointestinal cryptosporidiosis, while 6 cases were giardiasis. In patients with giardiasis, children were among the high-risk groups, making up 66.7% of these patients. The common presenting signs and symptoms were: diarrhea (83.3%), loss of appetite (83.3%), lethargy (83.3%), fever (66.7%), nausea/vomiting (50.0%), abdominal pain (16.7%), dehydration (16.7%) and rigor and chills (16.7%). Metronidazole was the drug of choice and was given to all symptomatic patients (83.3%). For the blood samples, 28 of the 92 peripheral smears for Plasmodium spp infection were diagnosed as malaria. The age range was from 4 to 57, with a median of 32.5 years. The sex ratio (M:F) was 3.6:1, while the age group of 30-44 years was the most commonly affected in both sexes. The majority of patients were foreigners (60.7%) and non-professional (39%). Plasmodium vivax (71%) infection was the most common pathogen found in these patients, along with a history of traveling to an endemic area of malaria (31%). The predominant presenting signs and symptoms were: fever (27%), rigor and chills (24%), nausea/vomiting (15%) and headache (8%). Chloroquine and primaquine was the most common anti-malarial regimen used (78.6%) in these patients. The seroprevalence of toxoplasmosis in different groups was 258/443 (58%): seropositive for IgG 143 (32.3%); IgM 67 (15%); and IgG + IgM 48 (10.8%). The age range was from 1 to 85, with a mean of 34 (+/- SD 16.6) years. The predominant age group was 21 to 40 years (126; 28.4%). The sex ratio (M:F) was 1.2:1. Subjects were predominantly male (142; 32%) and the Malay (117; 26.4%). Of these, 32 cases were clinically diagnosed with ocular toxoplasmosis. The range of age was from 10 to 56 years with a mean of 30.5 (+/- SD 12.05) years. The sex ratio (M:F) was 1:1.7. The majority were in the age group of 21 to 40 years, female (20; 62.5%), and Malay (17; 53%). They were also single (16; 50%), unemployed (12; 37%), and resided outside Kuala Lumpur (21; 65.6%). The more common clinical presentations were blurring of vision (25; 78%), floaters (10; 31%) and pain in the eye (7; 22%). We found that funduscopic examination (100%) and seropositivity for anti-Toxoplasma antibodies (93.7%) were the main reasons for investigation. Choroidoretinitis was the most common clinical diagnosis (69%), while clindamycin was the most frequently used antimicrobial in all cases. Among HIV-infected patients, 10 cases were diagnosed as AIDS-related toxoplasmic encephalitis (TE) (9 were active and 1 had relapse TE). In addition, 1 case was confirmed as congenital toxoplasmosis.
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PMID:Parasitic infections in Malaysia: changing and challenges. 1643 80

Cryptosporidiosis and giardiasis are major public health concerns. The role of water and food in the epidemiology of these diseases is now well recognized. Molecular techniques are available to determine the species and genotypes of Cryptosporidium and Giardia and to distinguish human from non-human pathogens. Validated methods to determine the species, genotype and subgenotype that are present in heterologous mixtures should be applied to environmental samples to enable the monitoring and characterization of infection sources, disease tracking and the establishment of causative links to both waterborne and foodborne outbreaks. Meaningful interpretation of population structures and occurrence-prevalence baselines can be performed only by analysing a well-planned set of samples from all possible sources taken regularly over time, rather than focusing on outbreak investigations. For food, this includes such analyses in the country of origin.
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PMID:Tools for investigating the environmental transmission of Cryptosporidium and Giardia infections in humans. 1650 18

During a large waterborne giardiasis outbreak in Norway, many diarrheic patients were found to have Cryptosporidium infections. Gene sequencing identified these infections as Cryptosporidium parvum infections, although they were not identical. Whether these infections were due to a simultaneous outbreak of waterborne cryptosporidiosis or reflected background levels not normally detected is discussed.
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PMID:Cryptosporidium parvum infections in Bergen, Norway, during an extensive outbreak of waterborne giardiasis in autumn and winter 2004. 1651 75

Stool samples from patients with abdominal symptoms were used to evaluate different copro-diagnostic assays for the detection of Giardia and Cryptosporidium. Results from microscopical examination following conventional stool concentration and direct fluorescent-antibody methods were compared with various commercially available immunochromatographic and enzyme immunoassays. Of 220 samples, 45 were positive for Giardia and 17 for Cryptosporidium. For Giardia, the sensitivities obtained by Ridascreen Giardia, Rida Quick Giardia, Rida Quick Combi and Giardia-Strip were 82%, 80%, 80% and 44%, respectively. For Cryptosporidium, the sensitivities obtained by Rida Quick Cryptosporidium, Ridascreen Cryptosporidium, Rida Quick Combi and Cryptosporidium-Strip were 88%, 82%, 82% and 75%, respectively. The specificity of all tests was > or = 98%. Other intestinal parasites were present in 68 samples, but cross-reactions with other protozoan or helminthic parasites were not observed. Overall, the copro-antigen assays were less time-consuming and easier to perform, but were less sensitive than conventional microscopical methods. Thus, these tests might be a useful addition to, but not a substitute for microscopical methods in the diagnosis of travel-associated giardiasis and cryptosporidiosis.
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PMID:Evaluation of seven commercial antigen detection tests for Giardia and Cryptosporidium in stool samples. 1677 62

Data concerning the clinical and epidemiological features of travel-associated cryptosporidiosis are lacking. In order to investigate the impact of this disease on travellers' health, a retrospective study was conducted at the Institute of Tropical Medicine, Berlin. In total, 57 cryptosporidial infections were identified between 2000 and 2004, resulting in a prevalence of 2.9% in patients with travel-associated diarrhoea. Travel to south-central Asia, especially India, was associated with a higher prevalence of infection than was travel to other destinations. Clinically, the disease resembled giardiasis, but fever and arthralgias seemed to occur more frequently.
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PMID:Epidemiological and clinical features of travel-associated cryptosporidiosis. 1688

Samples of sewage influent from 40 sewage treatment works (STW) throughout Norway were examined for Cryptosporidium oocysts and Giardia duodenalis cysts. Both parasites were detected frequently (80% of STW were Cryptosporidium positive; 93% of STW were Giardia positive) and at maximum concentrations of > 20,000 parasites/liter. The data suggest giardiasis is more widespread, and/or occurs with greater infection intensity, than cryptosporidiosis in Norway. STW serving higher person equivalents were more likely to be positive and had higher parasite concentrations. Parasite concentrations were used to estimate the proportion of contributing populations that could be clinically infected. For Cryptosporidium, the highest estimates were up to 5 per 100,000 individuals for two populations in eastern Norway. For Giardia, the highest estimate was 40 infected per 100,000 persons (approximately five times the usual national annual average) contributing to an STW in western Norway. As this population experienced a large waterborne giardiasis outbreak 6 months after sampling, it can be speculated that regular challenge with Giardia may occur here. Most Giardia isolates in sewage influent were assemblage A, although some assemblage B isolates were detected. There was substantial heterogeneity, but most samples contained isolates similar to genotype A3. Removal efficiencies at two STW with secondary treatment processes were estimated to be approximately 50% for Cryptosporidium and > 80% for Giardia. An STW with minimal treatment had negligible removal of both parasites. Many STW in Norway have minimal treatment and discharge effluent into rivers and lakes, thus, risk of contamination of water courses by Cryptosporidium and Giardia is considerable.
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PMID:Occurrence of Cryptosporidium oocysts and Giardia cysts in sewage in Norway. 1688 79


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