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Review
. 2018 Oct 24:11:1921-1933.
doi: 10.2147/IDR.S141468. eCollection 2018.

Treatment-refractory giardiasis: challenges and solutions

Marco Lalle  1 , Kurt Hanevik  2   3
Affiliations
Review

Treatment-refractory giardiasis: challenges and solutions

Marco Lalle et al. Infect Drug Resist. .

Abstract

Giardia is the commonest parasitic diarrheal pathogen affecting humans and a frequent cause of waterborne/foodborne parasitic diseases worldwide. Prevalence of giardiasis is higher in children, living in poor, low hygiene settings in developing countries, and in travelers returning from highly endemic areas. The clinical picture of giardiasis is heterogeneous, with high variability in severity of clinical disease. It can become chronic or be followed by post-infectious sequelae. An alarming increase in cases refractory to the conventional treatment with nitroimidazoles (ie, metronidazole) has been reported in low prevalence settings, such as European Union countries, especially in patients returning from Asia. In view of its relevance, we aim in this review to recapitulate present clinical knowledge about Giardia, with a special focus on the challenge of treatment-refractory giardiasis. We propose a working definition of clinically drug-resistant giardiasis, summarize knowledge regarding resistance mechanisms, and discuss its clinical management according to research-based evidence and medical practice. Advances in development and identification of novel drugs and potential non-pharmacological alternatives are also reviewed with the overall aim to define knowledge gaps and suggest future directions for research.

Keywords: Giardia duodenalis; antigiardial therapy; drug resistance; giardiasis; treatment failure.

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Conflict of interest statement

Disclosure KH is supported by the Norwegian National Advisory Unit on Tropical Infectious Diseases, Haukeland University Hospital for his Giardia-related work. The authors report no other conflicts of interest in this work.

Figures

Figure 1
Figure 1
Current and novel drug options for the treatment of symptomatic giardiasis. Notes: Molecular structures of compounds correspond to those reported on PubChem (http://pubchem.ncbi.nlm.nih.gov). MTZ (PubChem number, CID 4173), furazolidone (CID 5323714), nitazoxanide (CID 41684), ABZ (CID 2082), chloroquine (CID 2719), quinacrine (CID 237), paromomycin (CID 165580), bacitracin (CID 10909430), auranofin (CID 16667669), disulfiram (CID 3117), fumagillin (CID 6917655), omeprazole (CID 4594), NBDHEX (CID 9817686). Abbreviations: ABZ, albendazole; MTZ, metronidazole.
Figure 2
Figure 2
Overview of known and potential factors associated with clinical drug treatment failure of giardiasis. Notes: Factors attributable to the drug, the host, the parasite, and the intestinal microbiota are listed herein and discussed in details in the main text. Factors for which evidence is still poor are written in italic. Abbreviations: CVID, common variable immunodeficiency; LPDs, lymphoproliferative disorders.
See this image and copyright information in PMC

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