Albendazole as a treatment for Giardia infection

Giardia duodenalis infection in the context of a community-based deworming and water, sanitation and hygiene trial in Timor-Leste

Background

Giardiasis is a common diarrhoeal disease caused by the protozoan Giardia duodenalis. It is prevalent in low-income countries in the context of inadequate access to water, sanitation and hygiene (WASH), and is frequently co-endemic with neglected tropical diseases such as soil-transmitted helminth (STH) infections. Large-scale periodic deworming programmes are often implemented in these settings; however, there is limited evidence for the impact of regular anthelminthic treatment on G. duodenalis infection. Additionally, few studies have examined the impact of WASH interventions on G. duodenalis.

Methods

The WASH for WORMS cluster randomised controlled trial was conducted in remote communities in Manufahi municipality, Timor-Leste, between 2012 and 2016. All study communities received four rounds of deworming with albendazole at six-monthly intervals. Half were randomised to additionally receive a community-level WASH intervention following study baseline. We measured G. duodenalis infection in study participants every six months for two years, immediately prior to deworming, as a pre-specified secondary outcome of the trial. WASH access and behaviours were measured using questionnaires.

Results

There was no significant change in G. duodenalis prevalence in either study arm between baseline and the final study follow-up. We found no additional benefit of the community-level WASH intervention on G. duodenalis infection (relative risk: 1.05, 95% CI: 0.72–1.54). Risk factors for G. duodenalis infection included living in a household with a child under five years of age (adjusted odds ratio, aOR: 1.35, 95% CI: 1.04–1.75), living in a household with more than six people (aOR: 1.32, 95% CI: 1.02–1.72), and sampling during the rainy season (aOR: 1.23, 95% CI: 1.04–1.45). Individuals infected with the hookworm Necator americanus were less likely to have G. duodenalis infection (aOR: 0.71, 95% CI: 0.57–0.88).

Conclusions

Prevalence of G. duodenalis was not affected by a community WASH intervention or by two years of regular deworming with albendazole. Direct household contacts appear to play a dominant role in driving transmission. We found evidence of antagonistic effects between G. duodenalis and hookworm infection, which warrants further investigation in the context of global deworming efforts.

Trial registration Australian New Zealand Clinical Trials Registry, ACTRN12614000680662. Registered 27 June 2014, retrospectively registered. https://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=366540.

Comparative Pathobiology of the Intestinal Protozoan Parasites Giardia lamblia, Entamoeba histolytica, and Cryptosporidium parvum

Protozoan parasites can infect the human intestinal tract causing serious diseases. In the following article, we focused on the three most prominent intestinal protozoan pathogens, namely, Giardia lamblia, Entamoeba histolytica, and Cryptosporidium parvum. Both C. parvum and G. lamblia colonize the duodenum, jejunum, and ileum and are the most common causative agents of persistent diarrhea (i.e., cryptosporidiosis and giardiasis). Entamoeba histolytica colonizes the colon and, unlike the two former pathogens, may invade the colon wall and disseminate to other organs, mainly the liver, thereby causing life-threatening amebiasis. Here, we present condensed information concerning the pathobiology of these three diseases.

Pharmacokinetic investigation of albendazole and praziquantel in Thai children infected withGiardia intestinalis

The pharmacokinetics of albendazole/albendazole sulphoxide and praziquantel were investigated in Thai children with Giardia infection. Twenty school-age children were randomly allocated to receive either a single oral dose of albendazole (400 mg/child) or the same dose of albendazole given concurrently with a single oral dose of praziquantel (20 mg/kg). The concentrations of albendazole/albendazole sulphoxide and praziquantel in plasma samples, collected at intervals in the first 24 h post-treatment, were then quantified using HPLC with ultra-violet detection. No significant pharmacokinetic interaction between the albendazole and praziquantel was demonstrated. For albendazole sulphoxide, the active metabolite of albendazole, there was marked inter-individual variation in the maximum plasma concentration and the 'area under the curve'. The pharmacokinetics of albendazole sulphoxide were similar whether albendazole was given alone or in combination with praziquantel.

A meta-analysis of the effectiveness of albendazole compared with metronidazole as treatments for infections with Giardia duodenalis

BACKGROUND

Metronidazole is the most commonly used drug for the treatment of giardiasis in humans. In spite of its therapeutic efficacy for giardiasis, low patient compliance, especially in children, side effects, and the emergence of metronidazole-resistant strains may restrict its use. Albendazole has been used to treat Giardia duodenalis infections in recent years. However, efficacy studies in vivo and in vitro have produced diverse results as to its effectiveness. A moderately benign side effect profile, combined with established efficacy against many helminths, renders it promising for treatment of giardiasis in humans.

METHODOLOGY AND PRINCIPAL FINDINGS

We performed a search in the PubMed, Scopus, EMBASE, the ISI Web of Science, LILIACS, and Cochrane Controlled Trials Register for trials published before February 2010 as well as in references of relevant research and review articles. Eight randomized clinical trials (including 900 patients) comparing the effectiveness of albendazole with that of metronidazole were included in meta-analysis. After extracting and validating the data, the pooled risk ratio (RR) was calculated using an inverse-variance random-effects model. Albendazole was found to be equally as effective as metronidazole in the treatment of giardiasis in humans (RR 0.97; 95% CI, 0.93, 1.01). In addition, safety analysis suggested that patients treated with albendazole had a lower risk of adverse effects compared with those who received metronidazole (RR 0.36; 95% CI, 0.10, 1.34), but limitations of the sample size precluded a definite conclusion.

CONCLUSIONS/SIGNIFICANCE

The effectiveness of albendazole, when given as a single dose of 400 mg/day for 5 days, was comparable to that of metronidazole. Patients treated with albendazole tended to have fewer side effects compared with those who took metronidazole. Given the safety, effectiveness, and low costs of albendazole, this drug could be potentially used as an alternative and/or a replacement for the existing metronidazole therapy protocols in the treatment of giardiasis in humans.

WITHDRAWN: Drugs for treating giardiasis

BACKGROUND

There can be a high rate of recurrence of disease after initial drug treatment for giardiasis. These drugs also have a range of adverse effects.

OBJECTIVES

The objective of this review was to assess the effects of drug treatments for giardiasis.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, EMBASE, Current Contents, and reference lists of articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials of drug therapy for giardiasis compared with placebo or another drug.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Thirty-four trials were included. Only one trial was without serious methodological flaws. Compared with placebo, drug treatment was associated with an improved cure rate (odds ratio 11.51, 95% confidence interval 2.29 to 57.98). Metronidazole treatment longer than three days had a better parasitological cure rate than other long treatment courses (odds ratio 2.41, 95% confidence interval 1.31 to 4.44), but there was significant heterogeneity between the trials. Available evidence has not detected a difference in cure between single dose therapy and longer treatment courses (odds ratio 0.33, 95% confidence interval 0.08 to 1.34). Within the single dose regimens, the available evidence did not demonstrate a difference in parasitological cure rate between tinidazole and other short therapies (odds ratio 3.39, 95% confidence interval 0.95 to 12.04), but had a higher clinical cure rate (odds ratio 5.33, 95% 2.66 to 10.67).

AUTHORS' CONCLUSIONS

A single dose of tinidazole appears to give the highest clinical cure rate for giardiasis with relatively few adverse effects.

Comparison of chloroquine, albendazole and tinidazole in the treatment of children with giardiasis

In a comparative trial, 165 Cuban children with confirmed giardiasis were randomized to receive albendazole (400 mg/day for 5 days), chloroquine (10 mg/kg twice daily for 5 days) or tinidazole (50 mg/kg, as a single dose). Parasitological follow-up was based on faecal samples collected 7 and 10 days after the completion of treatment. The tinidazole and chloroquine appeared equally effective (P > 0.05), curing 91% and 86% of the children treated, respectively, and significantly better (P < 0.01) than the albendazole, which only cured 62% of the children given it. All three drugs were well accepted and tolerated, with only mild, transient and self-limiting side-effects reported. Chloroquine appears to be a good alternative to tinidazole for the treatment of paediatric patients with giardiasis.

Treatment of giardiasis

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.

Drugs for treating giardiasis

BACKGROUND

There can be a high rate of recurrence of disease after initial drug treatment for giardiasis. These drugs also have a range of adverse effects.

OBJECTIVES

The objective of this review was to assess the effects of drug treatments for giardiasis.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, Medline and Embase, Current Contents, reference lists of articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials of drug therapy for giardiasis compared with placebo or another drug.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Thirty-four trials were included. Only one trial was without serious methodological flaws. Compared with placebo, drug treatment was associated with an improved cure rate (odds ratio 11.5, 95% confidence interval 2.3 to 58). Metronidazole treatment longer than three days had a better parasitological cure rate than other long treatment courses (odds ratio 2.4, 95% confidence interval 1.3 to 4.4), but there was significant heterogeneity between the trials. Single dose therapy appeared equally effective as longer treatment courses (odds ratio 0.33, 95% confidence interval 0.08 to 1.34). Within the single dose regimens, tinidazole had a comparable parasitological cure rate to other short therapies (odds ratio 3.4, 95% confidence interval 0.95 to 12), but had a higher clinical cure rate (odds ratio 5.3, 95% 2.7-10.7).

REVIEWER'S CONCLUSIONS

A single dose of tinidazole appears to give the highest clinical cure rate for giardiasis with relatively few adverse effects.