Treatment of giardiasis.

Division of Infectious Diseases, University of Connecticut Health Center, Farmington, Connecticut 06030-3212, USA.
Clinical Microbiology Reviews (Impact Factor: 16). 02/2001; 14(1):114-28. DOI: 10.1128/CMR.14.1.114-128.2001
Source: PubMed

ABSTRACT 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.

1 Follower
  • [Show abstract] [Hide abstract]
    ABSTRACT: Forty nine rats (28 Rattus rattus and 21 Rattus norvegicus) were trapped from various locations at Taif governorate, and examined parasitological for defining of enteric parasites and associated pathogenic bacteria. The recovered enteric parasites were Hymenolepis nana, Hymenolepis dimenuta, Giardia Lamblia cyst, Entamoeba histolytica and Cryptosporidium. The incidence rate recorded for the above mentioned parasites were 20.4, 18.3, 14.2, 10.2 and 6.1%, respectively. A total of 6 potentially pathogenic bacteria were recovered from the trapped rats. These include Salmonella typhimurium, Providencia rettgeri, Escherichia coli, Klebsiella pneuomoniae, Pseudomonas aeruginosa and Streptococcus faecalis. This present study indicated that the type of enteric parasites and associated pathogenic bacteria in rats varied according to the localities, and furthermore highlighted role of rats as a biological reservoir of enteric parasites and pathogenic bacteria. The study has also provided evidence of efficiency and importance in regard for preventive control procedures which have a good effect upon prevalence of parasitological and bacterial, and furthermore highlighted the infections of human and animals. It was worthy to mention that the parasitic helminthes identified and bacterial strains isolated and accompanied together are recorded for the first time from Taif Governorate rats in KSA as a new host and locality records. The public health significance of each isolated parasite and bacterial species for man and animal as well as the symptoms and pathology of the diseases they cause, will be discussed in details in this paper.
    African journal of microbiology research 04/2012; 6(14). DOI:10.5897/AJMR11.1356 · 0.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    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 · 3.94 Impact Factor
  • Source
    [Show description] [Hide description]
    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.


Available from
May 31, 2014