Intestinal parasites in returned travelers

Wittner, Murray; Tanowitz, Herbert B.

doi:10.1016/s0025-7125(16)30295-4

Cited by 13 publications

(9 citation statements)

References 70 publications

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“…Although large outbreaks have been linked to contaminated water (123), the fecal-oral route is regarded as the major source of infection, particularly in countries where the water is warm or there is little drainage and no reticulated water supply (143). This premise is supported by the prevalence of giardiasis in child care centers and nursing homes for the elderly (39,136,232). The WHO estimated that 280 million people are infected each year.…”

Section: Giardia Duodenalismentioning

confidence: 99%

“…Giardia is the most common cause of chronic diarrhea in travelers (59,232,239). Although infections vary from asymptomatic through diarrhea and weight loss to profound weight loss and failure to thrive, there are currently no genetic markers or classification systems to distinguish pathogenic from nonpathogenic strains, notwithstanding various isoenzyme (6,129,190), DNA fingerprinting (203,207), and electrophoretic karyotyping (220,221) techniques to identify isolates.…”

Section: Giardia Duodenalismentioning

confidence: 99%

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Drug Targets and Mechanisms of Resistance in the Anaerobic Protozoa

2001

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The anaerobic protozoa Giardia duodenalis, Trichomonas vaginalis, and Entamoeba histolytica infect up to a billion people each year. G. duodenalis and E. histolytica are primarily pathogens of the intestinal tract, although E. histolytica can form abscesses and invade other organs, where it can be fatal if left untreated. T. vaginalis infection is a sexually transmitted infection causing vaginitis and acute inflammatory disease of the genital mucosa. T. vaginalis has also been reported in the urinary tract, fallopian tubes, and pelvis and can cause pneumonia, bronchitis, and oral lesions. Respiratory infections can be acquired perinatally. T. vaginalis infections have been associated with preterm delivery, low birth weight, and increased mortality as well as predisposing to human immunodeficiency virus infection, AIDS, and cervical cancer. All three organisms lack mitochondria and are susceptible to the nitroimidazole metronidazole because of similar low-redox-potential anaerobic metabolic pathways. Resistance to metronidazole and other drugs has been observed clinically and in the laboratory. Laboratory studies have identified the enzyme that activates metronidazole, pyruvate:ferredoxin oxidoreductase, to its nitroso form and distinct mechanisms of decreasing drug susceptibility that are induced in each organism. Although the nitroimidazoles have been the drug family of choice for treating the anaerobic protozoa, G. duodenalis is less susceptible to other antiparasitic drugs, such as furazolidone, albendazole, and quinacrine. Resistance has been demonstrated for each agent, and the mechanism of resistance has been investigated. Metronidazole resistance in T. vaginalis is well documented, and the principal mechanisms have been defined. Bypass metabolism, such as alternative oxidoreductases, have been discovered in both organisms. Aerobic versus anaerobic resistance in T. vaginalis is discussed. Mechanisms of metronidazole resistance in E. histolytica have recently been investigated using laboratory-induced resistant isolates. Instead of downregulation of the pyruvate:ferredoxin oxidoreductase and ferredoxin pathway as seen in G. duodenalis and T. vaginalis, E. histolytica induces oxidative stress mechanisms, including superoxide dismutase and peroxiredoxin. The review examines the value of investigating both clinical and laboratory-induced syngeneic drug-resistant isolates and dissection of the complementary data obtained. Comparison of resistance mechanisms in anaerobic bacteria and the parasitic protozoa is discussed as well as the value of studies of the epidemiology of resistance

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Section: Giardia Duodenalismentioning

confidence: 99%

Section: Giardia Duodenalismentioning

confidence: 99%

Drug Targets and Mechanisms of Resistance in the Anaerobic Protozoa

2001

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“…The binucleated parasite is found worldwide, but the incidence of giardiasis in humans is highest in developing countries, where the disease is a significant cause of morbidity, especially in children (11). In addition, giardiasis is regarded as one of the most common causes of traveler's diarrhea (7,25,38,40).…”

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confidence: 99%

A Sphingolipid Inhibitor Induces a Cytokinesis Arrest and Blocks Stage Differentiation in Giardia lamblia

Sonda

Štefanić

Hehl

2008

Antimicrob Agents Chemother

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Sphingolipid biosynthesis pathways have recently emerged as a promising target for therapeutic intervention against pathogens, including parasites. A key step in the synthesis of complex sphingolipids is the glucosylation of ceramide, mediated by glucosylceramide (GlcCer) synthase, whose activity can be inhibited by PPMP (1-phenyl-2-palmitoylamino-3-morpholino-1-propanol). In this study, we investigated whether PPMP inhibits the proliferation and differentiation of the pathogenic parasite Giardia lamblia, the major cause of parasiteinduced diarrhea worldwide. PPMP was found to block in vitro parasite replication in a dose-dependent manner, with a 50% inhibitory concentration of 3.5 M. The inhibition of parasite replication was irreversible at 10 M PPMP, a concentration that did not affect mammalian cell metabolism. Importantly, PPMP inhibited the completion of cell division at a specific stage in late cytokinesis. Microscopic analysis of cells incubated with PPMP revealed the aberrant accumulation of cellular membranes belonging to the endoplasmic reticulum network in the caudal area of the parasites. Finally, PPMP induced a 90% reduction in G. lamblia differentiation into cysts, the parasite stage responsible for the transmission of the disease. These results show that PPMP is a powerful inhibitor of G. lamblia in vitro and that as-yet-uncharacterized sphingolipid biosynthetic pathways are potential targets for the development of anti-G. lamblia agents.

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“…Increasing the sensitivity of parasite detection in coprodiagnostics can be approached by different means. Examination of multiple stool samples is Often recommended as providing better chances for the demonstration of intestinal parasites, especially for epidemiological studies (19)(20)(21)(22)(23).…”

Section: Discussionmentioning

confidence: 99%

Detection ofGiardia lamblia cysts in stool samples by immunofluorescence using monoclonal antibody

Winiecka-Krusnell

Linder

1995

Eur. J. Clin. Microbiol. Infect. Dis.

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The diagnostic potential of indirect immunofluorescence to detect Giardia cysts in stool samples using a cyst-specific anti-Giardia lamblia monoclonal antibody was evaluated in comparison to conventional light microscopy. One hundred fifty specimens from clinically suspected Giardia infections and 50 control samples from microscopically proved Giardia infections were tested. Giardia cysts were found in 15 of 150 (10%) samples tested by light microscopy, whereas immunofluorescence microscopy detected 35 of 150 (23%) positive samples. Forty-six of the 50 reference samples previously shown to contain Giardia cysts were positive. Apparently, the four discrepant samples contained very low numbers of parasites, as none could be detected by conventional microscopy. The results show that Giardia lamblia cysts are detected significantly more frequently using the antibody marker. The doubled number of positive stool specimens and detection of as little as four cysts per sample suggest that microscopical examination of samples can be improved by immunofluorescent staining of Giardia lamblia cysts.

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Intestinal parasites in returned travelers

Cited by 13 publications

References 70 publications

Drug Targets and Mechanisms of Resistance in the Anaerobic Protozoa

Drug Targets and Mechanisms of Resistance in the Anaerobic Protozoa

A Sphingolipid Inhibitor Induces a Cytokinesis Arrest and Blocks Stage Differentiation in Giardia lamblia

Detection ofGiardia lamblia cysts in stool samples by immunofluorescence using monoclonal antibody

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