Treatment of Giardiasis

Division of Infectious Diseases, University of Connecticut Health Center, Farmington, Connecticut 06030-3212, USA.
Clinical Microbiology Reviews (Impact Factor: 17.41). 02/2001; 14(1):114-28. DOI: 10.1128/CMR.14.1.114-128.2001
Source: PubMed


Giardia lamblia is both the most common intestinal parasite in the United States and a frequent cause of diarrheal illness throughout the world. In spite of its recognition as an important human pathogen, there have been relatively few agents used in therapy. This paper discusses each class of drugs used in treatment, along with their mechanism of action, in vitro and clinical efficacy, and side effects and contraindications. Recommendations are made for the preferred treatment in different clinical situations. The greatest clinical experience is with the nitroimidazole drugs, i.e., metronidazole, tinidazole, and ornidazole, which are highly effective. A 5- to 7-day course of metronidazole can be expected to cure over 90% of individuals, and a single dose of tinidazole or ornidazole will cure a similar number. Quinacrine, which is no longer produced in the United States, has excellent efficacy but may be poorly tolerated, especially in children. Furazolidone is an effective alternative but must be administered four times a day for 7 to 10 days. Paromomycin may be used during early pregnancy, because it is not systematically absorbed, but it is not always effective. Patients who have resistant infection can usually be cured by a prolonged course of treatment with a combination of a nitroimidazole with quinacrine.

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    • "In spite of its recognition as an important human pathogen for a long time , nearly 5 , 000 people are hospitalized with giardiasis annually in the United States ( see ( Lengerich et al . , 1994 ; Gardner and Hill , 2001 ) and references therein ). The disease spreads through fecal - oral trans mission of the parasite cysts ( Adam , 2001 ) . "
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    ABSTRACT: Giardiasis is a common diarrheal disease worldwide caused by the protozoan parasite Giardia (G.) intestinalis. It is urgent to develop novel drugs to treat giardiasis, due to increasing clinical resistance to the gold standard drug metronidazole (MTZ). New potential antiparasitic compounds are usually tested for their killing efficacy against G. intestinalis under anaerobic conditions, in which MTZ is maximally effective. On the other hand, though commonly regarded as an ‘anaerobic pathogen’, G. intestinalis is exposed to relatively high O2 levels in vivo, living attached to the mucosa of the proximal small intestine. It is thus important to test the effect of O2 when searching for novel potential antigiardial agents, as outlined in a previous study (Bahadur, Mastronicola et al. (2014) Antimicrob. Agents Chemother. 58, 543). Here, forty-five novel chalcone derivatives with triazolyl-quinolone scaffold were synthesized, purified and characterized by high resolution mass spectrometry, 1H and 13C nuclear magnetic resonance and infrared spectroscopy. Efficacy of the compounds against G. intestinalis trophozoites was tested under both anaerobic and microaerobic conditions, and selectivity was assessed in a counter-screen on human epithelial colorectal adenocarcinoma cells. MTZ was used as a positive control in the assays. All the tested compounds proved to be more effective against the parasite in the presence of O2, with the exception of MTZ that was less effective. Under anaerobiosis eighteen compounds were found to be as effective as MTZ or more (up to 3-4 fold); the same compounds proved to be up to > 100 fold more effective than MTZ under microaerobic conditions. Four of them represent potential candidates for the design of novel antigiardial drugs, being highly selective against Giardia trophozoites. This study further underlines the importance of taking O2 into account when testing novel potential antigiardial compounds.
    Frontiers in Microbiology 04/2015; 6. DOI:10.3389/fmicb.2015.00256 · 3.99 Impact Factor
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    • "The main treatments against G. intestinalis are based on derivatives of the following compounds: acridine, mepacrine (Mendelson, 1980) and quinacrine (Harris et al. 2001); nitroimidazoles, including metronidazole (Freeman et al. 1997), tinidazole (Jokipii and Jokipii, 1980), ornidazole (Jokipii and Jokipii, 1982), and other 5-nitroimidazoles (Upcroft et al. 1999); benzimidazoles, albendazole (Dutta et al. 1994), mebendazole (Bulut et al. 1996), nitrofuranes, and furoxone (Pickering, 1985); and more recently, nitazoxanide, a nitrothiazole (Romero et al. 1997; Ponce-Macotela et al. 2001). However, these drugs all produce undesirable secondary effects, ranging from nausea, (Davidson, 1984) and metallic taste in the mouth (Spellman, 1985) to psychosis (Upcroft et al. 1996), carcinogenesis (Gardner and Hill, 2001) and possible genetic damage (Legator et al. 1975; Mitelman et al. 1976). In addition, there is evidence suggesting the selection of resistant strains to antigiardial drugs (Upcroft, 1994; Upcroft and Upcroft, 2001; Sangster et al. 2002; Dunn et al. 2010). "
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    DESCRIPTION: Giardiosis is a neglected parasitic disease that produces diarrhoea and different degrees of malabsorption in humans and animals. Its treatment is based on derivatives of 5-nitroimidazoles, benzimidazoles, nitrofuranes, acridine and nitrotiazoles. These drugs produce undesirable secondary effects, ranging from a metallic taste in the mouth to genetic damage and the selection of resistant strains; therefore, it is necessary to develop new therapeutic alternatives. We demonstrated that a 2-h treatment with 2·87 μg ml(-1) of fraction 6 of Lippia graveolens (F-6) was sufficient to kill half of an experimental Giardia intestinalis (Syn. G. duodenalis, G. lamblia) population, based on the reduction of MTT-tetrazolium salt levels. F-6 breaks the nuclear envelope and injures the ventral suckling disc. The major compounds of F-6 were characterized as naringenin, thymol, pinocembrin and traces of compounds not yet identified. The results suggest that Lippia is a potential source to obtain compounds with anti-Giardia activity. This knowledge is an important starting point to develop new anti-giardial drugs. Future studies will be required to establish the efficacy of F-6 in vivo using an animal model.
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    • "When an infant is not exclusively breastfed, other contributing factors in preparation of artificial formula or complementary foods can be risk factors for parasitic infections. Contamination of infant feeding by water infected by animal or human excreta, inadequate chlorination of water and person to person fecooral transmission are risk factors [3] [13] [14] . Aggravation of this situation by human sociopolitical disasters like refugees and refugee settlements have reported frequent strongyloidosis and other parasitic infections linked to sanitation, poor quality of drinking water and lack of foot wear [15] . "
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    ABSTRACT: Breastfeeding, as exclusive nutrition in the first six months of life, is a necessary nutritional requisite in infants. Except for very few maternal diseases that contraindicate breastfeeding, some of which still controversial, breastfeeding mothers must continue exclusive and sustained lactation to provide maximum overall benefits through breastfeeding. Parasitic infections is a global disease and children remain a significant proportion of the affected population. The complex and mandatory life cycles of some parasites, particularly the helminths may partly explain their geographical distribution. The world-wide prevalence of parasitic infections as well as the largely asymptomatic nature of most infections, make many of these infections to likely remain under-recognized. Breast milk, the prime infant nutrition must be recognized to be more than a rare vehicle of parasite transmission, but also a general and focused immune defensive tool against some important parasites. The possibility and influence of small quantities of parasite antigens in breast milk have not been adequately explored. It is believed that useful immunological responses both direct and indirect in breast milk that occur due to the presence of parasite antigens, must be further studied in the light of both immediate and long term benefits. Within this context, and prompted by a spectrum of existing uncertainties, researched and hypothetical roles of parasites and associated immunological responses in the lactating mammary gland are proposed and reviewed.
    Asian Pacific Journal of Tropical Biomedicine 11/2014; 4(11):847-858. DOI:10.12980/APJTB.4.201414B355
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