Probiotics in the management of Giardia duodenalis: an update on potential mechanisms and outcomes.

Giardia duodenalis is a common cause of infection in children and travelers. The most frequent symptom is diarrhea in these patients. G. duodenalis trophozoites use a highly specialized adhesive disc to attach the host intestinal epithelium to induce intestinal damages. Pathological features of the small intestine following giardiasis include villous atrophy; infiltration of granulocytes, lymphocytes, and plasma cells into the lamina propria; and nodular lymphoid hyperplasia. The disturbed intestinal microbiota has been observed in patients with giardiasis. Therefore, a growing body of evidence has emphasized restoring the gut microbiome by probiotics in giardiasis. This study aimed to review the literature to find the pathologic features of giardiasis and its relationship with imbalanced microbiota. Then, benefits of probiotics in giardiasis and their potential molecular mechanisms were discussed. It has been illustrated that using probiotics (e.g., Lactobacillus and Saccharomyces) can reduce the time of gastrointestinal symptoms and repair the damages, particularly in giardiasis. Probiotics' capability in restoring the composition of commensal microbiota may lead to therapeutic outcomes. According to preclinical and clinical studies, probiotics can protect against parasite-induced mucosal damages via increasing the antioxidant capacity, suppressing oxidative products, and regulating the systemic and mucosal immune responses. In addition, they can reduce the proportion of G. duodenalis load by directly targeting the parasite. They can destroy the cellular architecture of parasites and suppress the proliferation and growth of trophozoites via the production of some factors with anti-giardial features. Further researches are required to find suitable probiotics for the prevention and treatment of giardiasis.

Drug resistance in Giardia: Mechanisms and alternative treatments for Giardiasis.

The use of chemotherapeutic drugs is the main resource against clinical giardiasis due to the lack of approved vaccines. Resistance of G. duodenalis to the most used drugs to treat giardiasis, metronidazole and albendazole, is a clinical issue of growing concern and yet unknown impact, respectively. In the search of new drugs, the completion of the Giardia genome project and the use of biochemical, molecular and bioinformatics tools allowed the identification of ligands/inhibitors for about one tenth of ≈150 potential drug targets in this parasite. Further, the synthesis of second generation nitroimidazoles and benzimidazoles along with high-throughput technologies have allowed not only to define overall mechanisms of resistance to metronidazole but to screen libraries of repurposed drugs and new pharmacophores, thereby increasing the known arsenal of anti-giardial compounds to some hundreds, with most demonstrating activity against metronidazole or albendazole-resistant Giardia. In particular, cysteine-modifying agents which include omeprazole, disulfiram, allicin and auranofin outstand due to their pleiotropic activity based on the extensive repertoire of thiol-containing proteins and the microaerophilic metabolism of this parasite. Other promising agents derived from higher organisms including phytochemicals, lactoferrin and propolis as well as probiotic bacteria/fungi have also demonstrated significant potential for therapeutic and prophylactic purposes in giardiasis. In this context the present chapter offers a comprehensive review of the current knowledge, including commonly prescribed drugs, causes of therapeutic failures, drug resistance mechanisms, strategies for the discovery of new agents and alternative drug therapies.

La propolina por intubación duodenal como tratamiento de la giardiasis / The propoline by duodenal intubation as a treatment of giardiasis

Introducción: la giardiasis es una enfermedad infecciosa del intestino de distribución universal producida por un parásito flagelado, la Giardia lamblia.Objetivo: evaluar los resultados de la intubación duodenal con propolina en pacientes con giardiasis que presentaron recidivas luego del tratamiento con antiparasitarios sintéticos orales. Método: se realizó una investigación experimental en el Hospital General Provincial Docente Dr Antonio Luaces Iraola, en el período de enero a marzo de 2014 en 22 pacientes con diagnóstico de giardiasis que no respondían a los tratamientos convencionales y cumplían los criterios de inclusión propuestos en el estudio.Resultados: la giardiasis predominó en el sexo femenino, prevalecieron las edades entre los 21 y 30 años. Un alto porcentaje de los pacientes presentó una forma asintomática de la infección y el tratamiento previo más utilizado fue el tinidazol. El 86,4 por ciento de los pacientes respondieron positivamente al tratamiento. Conclusiones: la terapia con propolina resultó de utilidad en pacientes diagnosticados con giardiasis que no respondieron a tratamientos medicamentosos habituales(AU)

Introduction: giardiasis is an infectious disease of the intestine of universal distribution produced by a flagellated parasite, Giardia lamblia.Objective: to evaluate the results of duodenal intubation with propoline in patients with giardiasis who presented recurrence after treatment with oral synthetic antiparasitic agents.Method: an experimental research was carried out in the General Provincial Teaching Hospital Dr Antonio Luaces Iraola , in the period from January to March 2014 in 22 patients diagnosed with giardiasis that did not respond to conventional treatments and met the inclusion criteria proposed in the study.Results: giardiasis predominated in the female sex, prevailing ages between 21 and 30 years. A high percentage of patients presented an asymptomatic form of the infection and the most used previous treatment was tinidazole. 86,4 percent of the patients responded positively to the treatment.Conclusions: propoline therapy was useful in patients diagnosed with giardiasis who did not respond to usual medication treatments(AU)

Hemolytic, anticancer and antigiardial activity of Palythoa caribaeorum venom

Cnidarian venoms and extracts have shown a broad variety of biological activities including cytotoxic, antibacterial and antitumoral effects. Most of these studied extracts were obtained from sea anemones or jellyfish. The present study aimed to determine the toxic activity and assess the antitumor and antiparasitic potential of Palythoa caribaeorum venom by evaluating its in vitro toxicity on several models including human tumor cell lines and against the parasite Giardia intestinalis. Methods: The presence of cytolysins and vasoconstrictor activity of P. caribaeorum venom were determined by hemolysis, PLA2 and isolated rat aortic ring assays, respectively. The cytotoxic effect was tested on HCT-15 (human colorectal adenocarcinoma), MCF-7 (human mammary adenocarcinoma), K562 (human chronic myelogenous leukemia), U251 (human glyoblastoma), PC-3 (human prostatic adenocarcinoma) and SKLU-1 (human lung adenocarcinoma). An in vivo toxicity assay was performed with crickets and the antiparasitic assay was performed against G. intestinalis at 24 h of incubation. Results: P. caribaeorum venom produced hemolytic and PLA2 activity and showed specific cytotoxicity against U251 and SKLU-1 cell lines, with approximately 50% growing inhibition. The venom was toxic to insects and showed activity against G. intestinalis in a dose-dependent manner by possibly altering its membrane osmotic equilibrium. Conclusion: These results suggest that P. caribaeorum venom contains compounds with potential therapeutic value against microorganisms and cancer.(AU)

Cryptosporidium and Giardia Infections in Children: A Review.

Diarrheal disease remains the second leading cause of mortality in children in developing countries. Cryptosporidium is a leading cause and its importance stands to increase as rotavirus vaccine becomes used around the world. Cryptosporidium is particularly problematic in children younger than 2 years old and in the immunocompromised. Giardia lamblia is a common intestinal protozoan that is associated with diarrhea and, perhaps, growth faltering in impoverished settings. This review establishes the current prevalence of these infections in global settings and reviews current diagnosis and management approaches.

Prevalence and Characteristics of Duodenal Villous Atrophy in Renal Transplant Patients Presenting With Persistent Diarrhea in a Developing Country.

OBJECTIVES: Persistent diarrhea is a common complication after solid-organ transplant, including kidney transplant. Data on duodenal villous atrophy as a cause of persistent diarrhea in renal transplant recipients are scarce. MATERIALS AND METHODS: We conducted a prospective analysis of 207 patients who received renal transplants from 2009 to 2012 with persistent diarrhea and who underwent upper gastrointestinal endoscopy and duodenal biopsies. Duodenal biopsies were examined for duodenal villous atrophy. Age, sex, transplant duration, and drugs were compared between patients with and without duodenal villous atrophy. After exclusion of known causes of duodenal villous atrophy, a 3-month course of antibiotics was given and outcomes were analyzed. RESULTS: Of 207 renal transplant recipients, 104 patients (49.8%) displayed duodenal villous atrophy. Of these, 92 (88.5%) were male patients. The mean age of patients with duodenal villous atrophy was 34.9 ± 10.3 years. The mean onset of persistent diarrhea in DVA-positive patients posttransplant was 2.16 ± 0.8 years. Celiac disease serology was positive in 18 (17.3) patients. Giardiasis was demonstrated in 11 patients (10.7%), whereas immunoproliferative small intestinal disease was shown in 7 patients (6.8%). The remaining 68 patients (65.38%) received antibiotics, with 50 recipients (74.6%) showing complete response, although 13 of these patients (26%) relapsed. Among the remaining 18 patients (26.47%), 9 (50%) had other causes and 9 (50%) had no cause found. Isoniazid prophylaxis showed statistically significant negative association with duodenal villous atrophy. CONCLUSIONS: Duodenal villous atrophy is highly prevalent in renal transplant recipients irrespective of age, sex, and posttransplant duration. We found tropical sprue, giardiasis, immunoproliferative small intestinal disease, and celiac disease to be important causes of duodenal villous atrophy. Therefore, duodenal biopsy is recommended in renal transplant recipients with persistent diarrhea.

Efectividad del Oleozon® por vía oral en pacientes con giardiasis / Effectiveness of the oral Oleozon® in patients with giardiasis

Se realizó una intervención terapéutica en 108 adultos con giardiasis, atendidos en el Servicio de Medicina Natural y Tradicional del Centro Médico Psicopedagógico América Labadí Arce de Santiago de Cuba, desde julio del 2013 hasta igual periodo del 2014, con vistas a determinar la efectividad del Oleozon® por vía oral en los afectados. Se conformaron 2 grupos de 54 integrantes cada uno; el de estudio, recibió Oleozon®, y el de control, fue tratado con medicamentos convencionales. Se empleó la prueba de Ji al cuadrado, con una significación estadística de p < 0,05. Predominaron el sexo masculino (59,2 por ciento en el grupo de estudio y 55,5 por ciento en el de control), el grupo etario de 30-39 años (38,9 por ciento en el primero y 51,8 por ciento en el segundo). La rápida evolución de los pacientes tratados con Oleozon® demostró su efectividad; por tanto, se recomendó su utilización como enfoque terapéutico de elección(AU)

A therapeutical intervention in 108 adults with giardiasis, assisted in the Natural and Traditional Medicine Service of America Labadí Arce Psychopedagogical Medical Center in Santiago de Cuba was carried out from July, 2013 to the same period of 2014, aimed at determining the effectiveness of the oral Oleozon® in those patients affected. Two groups of 54 members each were formed; the study group received Oleozon®, and the control group was treated with conventional drugs. The Chi square test was used, with a statistical significance of p 0,05. The male sex (59.2 percent in the study group and 55.5 percent in the control group), the age group 30-39 years (38.9 percent in the first one and 51.8 percent in the second one). The fast clinical course of the patients treated with Oleozon® demonstrated its effectiveness; therefore, its use was recommended as an alternative therapeutic approach(AU)

Componentes alimentarios vegetales y microbianos potencialmente útiles en el tratamiento y control de la giardiasis / Potentially useful in the treatment plant and microbial food components and control of giardiasis

La giardiasis es una infección intestinal de amplia distribución mundial, que presenta manifestaciones clínicas con variaciones desde la infección asintomática, a la enfermedad aguda o crónica asociada con diarrea prolongada y severa y malabsorción de nutrientes. Su agente etiológico es el protozoario Giardia lamblia. La infección se inicia por la ingestión de quistes del parásito, presentes en agua y/o alimentos contaminados o por contacto orofecal directo. Los mecanismos a través de los cuales G. lamblia causa le enfermedad permanecen aún en discusión, pero los principales postulados incluyen tanto alteraciones morfológicas como funcionales de la mucosa intestinal a causa de la adhesión de los trofozoítos a las células epiteliales mediante el disco ventral o suctorio, que afectaría la absorción de nutrientes. El principal tratamiento es la administración de drogas antiparasitarias, muchas de las cuales han demostrado tener un amplio rango de efectos secundarios desagradable, lo cual sumado a la ocurrencia de resultados clínicos insatisfactorios y al surgimiento de cepas resistentes, ha impulsado la búsqueda de nuevas estrategias terapéuticas. Es por ello que el objetivo de esta tesis doctoral fue evaluar la actividad antigiardiásica de componentes alimentarios de origen vegetal y microbiano, como así también la interacción de los mismos con drogas antiparasitarias de uso común.

ABSTRACT: Giardiasis is an intestinal infection of worldwide distribution, presenting with clinical manifestations ranging from asymptomatic infection to acute or chronic disease associated with prolonged and severe diarrhea and malabsorption of nutrients, Its etiologic agent is the protozoan Giardia lamblia. Infection is initiated by ingestion of parasite cysts present in contaminated water and food or by direct fecal-oral contact The mechanisms through which G. lamblia causes disease will remain still under discussion, but the main tenets include both mechanical obstruction as morphological and functional alterations of the intestinal mucosa because of the adherence of trophozoites to epithelial cells by ventral disk that affect nutrient absorption. The main treatment is the administration of antiparasitic drugs, many of which have been shown to have a wide range of unpleasant side effects, which added to the occurrence of unsatisfactory clinical results and the emergence of resistant strains, has prompted the search for new therapeutic strategies.

Atualidades sobre giardíase / Updates on giardiasis

A giardíase é uma parasitose intestinal amplamente distribuída pelo mundo, com alta prevalência em países em desenvolvimento, inclusive o Brasil. Embora seja uma infecção com bom prognóstico, pode apresentar gravidade em pessoas com desnutrição, fibrose cística ou algumas imunodeficiências. Este artigo tem como objetivo atualizar os principais aspectos da giardíase.

Giardiasis is an intestinal parasite widely distributed around the globe with high prevalence in developing countries, including Brazil. Although it is an infection with a good prognosis may present serious in people with malnutrition, cystic fibrosis or certain immunodeficiencies. The aim of this paper is to perform an update on key aspects of giardiasis.

Intervención para mejorar conocimientos, percepciones y prácticas en relación con el diagnóstico, tratamiento y control de la giardiasis / Intervention to improve knowledge, perceptions and practices in the diagnosis, treatment and control of giardiasis

Objetivo: evaluar los resultados de una intervención para mejorar conocimientos, percepciones y prácticas de los médicos relacionados con el diagnóstico, tratamiento y control de la giardiasis. Métodos: para indagar en los conocimientos, percepciones y prácticas de médicos de familia del municipio Playa, La Habana, en relación con el diagnóstico, tratamiento y control de la giardiasis, se diseñó, validó y aplicó a estos un cuestionario de 27 preguntas. Para atenuar las deficiencias evidenciadas con la aplicación de ese instrumento, se ejecutaron, a modo de intervención, un grupo de acciones de tipo académico. Esas medidas incluyeron la preparación, publicación y distribución gratuita a todos los médicos de un libro sobre giardiasis, así como la impartición de conferencias sobre el tema. Para evaluar los resultados de la intervención, a 6 meses de completada su puesta en práctica, se hizo una segunda aplicación del cuestionario antes mencionado. Resultados: la primera aplicación del cuestionario hizo evidente los conocimientos insuficientes, las percepciones inadecuadas y prácticas incorrectas. Por ejemplo, la media de respuestas correctas a las 19 interrogantes sobre aspectos cognoscitivos fue de 7,69. La segunda aplicación del instrumento permitió conocer de una significativa mejoría de los encuestados en la casi totalidad de los aspectos cognoscitivos, perceptuales y conductuales evaluados. Por ejemplo, la media de respuestas correctas a las preguntas sobre aspectos cognoscitivos resultó significativamente más alta (14,61; p< 0,0001). Conclusión: los resultados de la intervención realizada en el municipio Playa sugieren su extensión al resto del país y demuestran, una vez más, la necesidad de monitorear y actualizar con regularidad los programas de formación de médicos y especialistas en los aspectos relacionados con el diagnóstico, tratamiento y control de las enfermedades parasitarias(AU)

Objective: evaluate the results of an intervention aimed at improving physicians' knowledge, perceptions and practices in the diagnosis, treatment and control of giardiasis. Methods: a 27-question survey was designed, validated and given to family doctors from the municipality of Playa, Havana, aimed at inquiring about their knowledge, perceptions and practices in the diagnosis, treatment and control of giardiasis. To make up for deficiencies found in the application of this tool, a number of academic actions were implemented. For example, a book on giardiasis was prepared, published and distributed free-of-charge among all doctors, and lectures on the topic were delivered. Six months after implementation of the intervention, the questionnaire was applied again with the purpose of evaluating the results obtained. Results: the first application of the questionnaire revealed that knowledge was insufficient, perceptions inadequate and practices incorrect. For instance, the mean number of correct answers to the 19 questions on cognitive aspects was 7.69. The second application of the questionnaire showed a significant improvement in practically all the cognitive, perceptual and behavioral aspects evaluated. This time the mean number of correct answers to questions on cognitive aspects was significantly higher (14.61; p< 0.0001). Conclusion: the results obtained from the intervention implemented in the municipality of Playa point to the advisability of its expansion to the rest of the country. They also suggest, once again, the need to regularly monitor and update the contents of training programs for doctors and specialists in relation to the diagnosis, treatment and control of parasitic diseases(AU)

Intervención para mejorar conocimientos, percepciones y prácticas en relación con el diagnóstico, tratamiento y control de la giardiasis / Intervention to improve knowledge, perceptions and practices in the diagnosis, treatment and control of giardiasis

Objetivo: evaluar los resultados de una intervención para mejorar conocimientos, percepciones y prácticas de los médicos relacionados con el diagnóstico, tratamiento y control de la giardiasis. Métodos: para indagar en los conocimientos, percepciones y prácticas de médicos de familia del municipio Playa, La Habana, en relación con el diagnóstico, tratamiento y control de la giardiasis, se diseñó, validó y aplicó a estos un cuestionario de 27 preguntas. Para atenuar las deficiencias evidenciadas con la aplicación de ese instrumento, se ejecutaron, a modo de intervención, un grupo de acciones de tipo académico. Esas medidas incluyeron la preparación, publicación y distribución gratuita a todos los médicos de un libro sobre giardiasis, así como la impartición de conferencias sobre el tema. Para evaluar los resultados de la intervención, a 6 meses de completada su puesta en práctica, se hizo una segunda aplicación del cuestionario antes mencionado. Resultados: la primera aplicación del cuestionario hizo evidente los conocimientos insuficientes, las percepciones inadecuadas y prácticas incorrectas. Por ejemplo, la media de respuestas correctas a las 19 interrogantes sobre aspectos cognoscitivos fue de 7,69. La segunda aplicación del instrumento permitió conocer de una significativa mejoría de los encuestados en la casi totalidad de los aspectos cognoscitivos, perceptuales y conductuales evaluados. Por ejemplo, la media de respuestas correctas a las preguntas sobre aspectos cognoscitivos resultó significativamente más alta (14,61; p< 0,0001). Conclusión: los resultados de la intervención realizada en el municipio Playa sugieren su extensión al resto del país y demuestran, una vez más, la necesidad de monitorear y actualizar con regularidad los programas de formación de médicos y especialistas en los aspectos relacionados con el diagnóstico, tratamiento y control de las enfermedades parasitarias

Objective: evaluate the results of an intervention aimed at improving physicians' knowledge, perceptions and practices in the diagnosis, treatment and control of giardiasis. Methods: a 27-question survey was designed, validated and given to family doctors from the municipality of Playa, Havana, aimed at inquiring about their knowledge, perceptions and practices in the diagnosis, treatment and control of giardiasis. To make up for deficiencies found in the application of this tool, a number of academic actions were implemented. For example, a book on giardiasis was prepared, published and distributed free-of-charge among all doctors, and lectures on the topic were delivered. Six months after implementation of the intervention, the questionnaire was applied again with the purpose of evaluating the results obtained. Results: the first application of the questionnaire revealed that knowledge was insufficient, perceptions inadequate and practices incorrect. For instance, the mean number of correct answers to the 19 questions on cognitive aspects was 7.69. The second application of the questionnaire showed a significant improvement in practically all the cognitive, perceptual and behavioral aspects evaluated. This time the mean number of correct answers to questions on cognitive aspects was significantly higher (14.61; p< 0.0001). Conclusion: the results obtained from the intervention implemented in the municipality of Playa point to the advisability of its expansion to the rest of the country. They also suggest, once again, the need to regularly monitor and update the contents of training programs for doctors and specialists in relation to the diagnosis, treatment and control of parasitic diseases

Lactobacillus rhamnosus GG antagonizes Giardia intestinalis induced oxidative stress and intestinal disaccharidases: an experimental study.

The present study describes the in vivo modulatory potential of Lactobacillus rhamnosus GG (LGG), an effective probiotic, in Giardia intestinalis-infected BALB/c mice. Experimentally, it was observed that oral administration of lactobacilli prior or simultaneous with Giardia trophozoites to mice, efficiently (p < 0.05) reduced both the severity and duration of giardiasis. More specifically, probiotics fed, Giardia-infected mice, showed a significant increase in the levels of antioxidants [reduced glutathione (GSH) and superoxide dismutase (SOD)] and intestinal disaccharidases [sucrase and lactase] and decreased levels of oxidants in the small intestine, in comparison with Giardia-infected mice. Histopathological findings also revealed almost normal cellular morphology of the small intestine in probiotic-fed Giardia-infected mice compared with fused enterocytes, villous atrophy and increased infiltration of lymphocytes in Giardia-infected mice. The results of the present study has shed new light on the anti-oxidative properties of LGG in Giardia mediated tissue injury, thereby suggesting that the effects of probiotic LGG are biologically plausible and could be used as an alternative microbial interference therapy.

Evaluation of paediatric patients with protein losing enteropathy a single centre experience.

OBJECTIVE: The aim of the study is to evaluate paediatric patients with protein losing enteropathy (PLE). METHODS: Fourteen cases diagnosed as PLE were evaluated in terms ofaetiologies, diagnostic methods, laboratory findings, treatment procedures and long-term prognosis. RESULTS: Four of the cases had coeliac disease, three intestinal lymphangiectasia, three giardia infection, one H pylori infection and three cytomegalovirus (CMV) infection. Histopathological examinations of duodenum specimens revealed total villous atrophy in four cases, lymphatic dilatation in three cases, severe nodular appearance in four cases and no pathology in four cases. All of the cases except patients with intestinal lymphangiectasia were controlled by the appropriate treatment given for the underlying disease. The cases with CMV infection were treated with only supportive treatment and gancyclovir therapy was not needed. CONCLUSION: When proteinuria is not detected in well-appearing children admitted with oedema, PLE must be considered.

Probiotic Lactobacillus rhamnosus GG modulates the mucosal immune response in Giardia intestinalis-infected BALB/c mice.

BACKGROUND: Gut homeostasis can be altered by the oral administration of health-promoting microorganisms, namely probiotics that are known to reinforce the host immune response. AIM: The aim of this study was to elucidate the immunomodulatory effect of orally administered probiotic Lactobacillus rhamnosus GG (LGG) in Giardia-infected mice. METHODS: BALB/c mice were fed orally with probiotic LGG either 7 days prior to or simultaneously with the challenge dose of Giardia trophozoites. The administration of the probiotic was continued for 25 days, and immunomodulatory potentials in terms of secretory immunoglobulin A (IgA) levels, CD8+ and CD4+ T lymphocytes, and expression of pro-inflammatory [tumor necrosis factor-alpha, interferon-gamma (INF-γ)] and anti-inflammatory cytokines [interleukin (IL)-4, IL-6, IL-10] were studied. RESULTS: Oral feeding of LGG prior to or simultaneously with the test dose of Giardia seems to have modulated both arms (humoral and cellular) of the mucosal immune system since a significant increase in the levels of specific secretory IgA antibody, IgA+ cells, and CD4+ T lymphocytes were observed in contrast with the decreased percentage of cytotoxic CD8+ T lymphocytes. The stimulated mucosal immune response in probiotic fed Giardia-infected mice was further correlated with the enhanced levels of anti-inflammatory cytokines IL-6 and IL-10 and reduced levels of pro-inflammatory cytokine INF-γ. CONCLUSIONS: This is the first study to show that oral administration of the effective probiotic LGG to Giardia infected mice could be used as a bacterio-therapy that restores the normal gut microflora and modulates the mucosal immune response.

Protection against diarrhea associated with Giardia intestinalis Is lost with multi-nutrient supplementation: a study in Tanzanian children.

BACKGROUND: Asymptomatic carriage of Giardia intestinalis is highly prevalent among children in developing countries, and evidence regarding its role as a diarrhea-causing agent in these settings is controversial. Impaired linear growth and cognition have been associated with giardiasis, presumably mediated by malabsorption of nutrients. In a prospective cohort study, we aim to compare diarrhea rates in pre-school children with and without Giardia infection. Because the study was conducted in the context of an intervention trial assessing the effects of multi-nutrients on morbidity, we also assessed how supplementation influenced the relationship between Giardia and diarrhoea rates, and to what extent Giardia modifies the intervention effect on nutritional status. METHODS AND FINDINGS: Data were collected in the context of a randomized placebo-controlled efficacy trial with 2×2 factorial design assessing the effects of zinc and/or multi-micronutrients on morbidity (n=612; height-for-age z-score <-1.5 SD). Outcomes measures were episodes of diarrhea (any reported, or with ≥3 stools in the last 24 h) and fever without localizing signs, as detected with health-facility based surveillance. Giardia was detected in stool by enzyme-linked immunosorbent assay. Among children who did not receive multi-nutrients, asymptomatic Giardia infection at baseline was associated with a substantial reduction in the rate of diarrhea (HR 0.32; 0.15-0.66) and fever without localizing signs (HR 0.56; 0.36-0.87), whereas no such effect was observed among children who received multi-nutrients (p-values for interaction 0.03 for both outcomes). This interaction was independent of age, HAZ-scores and distance to the research dispensary. There was no evidence that Giardia modified the intervention effect on nutritional status. CONCLUSION: Although causality of the Giardia-associated reduction in morbidity cannot be established, multi-nutrient supplementation results in a loss of this protection and thus seems to influence the proliferation or virulence of Giardia or associated intestinal pathogens.

Lactobacillus casei as a probiotic in malnourished Giardia lamblia-infected mice: a biochemical and histopathological study.

The study describes the in vivo activity of Lactobacillus casei in malnourished Giardia lamblia-infected BALB/c mice. By experimentation, it was found that daily administration of the probiotic 7 days before inoculation with Giardia trophozoites in malnourished mice efficiently reduced both the severity and duration of giardiasis. More specifically, excretion of Giardia cysts and trophozoites counts were reduced, while faecal lactobacilli counts increased significantly in probiotic-fed malnourished mice, compared with control mice. Interestingly, it was also observed that oral feeding of the probiotic to malnourished mice abrogated all the anthropometric and biochemical anomalies. Histologically, morphological and cellular alteration of microvillus membrane integrity revealed that probiotic administration ameliorated the mucosal damage in malnourished, probiotic-inoculated, Giardia-infected mice compared with the severe microvillus atrophy, œdematous and vacuolated epithelial cells, and ileitis in malnourished Giardia-infected mice. The results clearly show the antigiardial effect of the probiotic in vivo by modulating the gut cells to inhibit the colonization and multiplication of Giardia trophozoites, thus reducing the severity and duration of murine giardiasis.

Giardiasis: the ever-present threat of a neglected disease.

Although giardiasis has been a threat to mankind for thousands of years, this protozoan infection was, until recently, relatively neglected. Giardia duodenalis is recognised as a major cause of parasite-induced diarrhoea in humans and animals, and is currently an important public health problem, placing a heavy burden on both diagnostic and treatment services at health care institutions, mostly in developing countries, but also in highly developed countries. Steady progress in recent years, using a combination of molecular, immunological, and clinical approaches, has substantially increased our understanding of Giardia and important aspects of the clinical manifestations that it causes. The purpose of this review is to provide an overview of the extent of Giardia infection, the implications of water and food in Giardia transmission, new aspects regarding clinical diagnosis and environmental detection, treatment, and some approaches towards prevention and control. A number of future research priorities are also presented.