Giardia is a flagellate protozoan with worldwide distribution that causes significant gastrointestinal diseases. The life cycle of the organism alternates between the active, proliferating trophozoite and the dormant cyst. 5-Nitroimida-zoles have been used extensively in the treatment of amoebiasis, giardiasis, and trichomoniasis. We have previously synthesized ...

Since the Giardia lamblia cyst wall is necessary for survival in the environment and host infection, we tested the hypothesis that it contains proteins other than the three known cyst wall proteins. Serial analysis of gene expression during growth and encystation revealed a gene, "HCNCp" (High Cysteine Non-variant Cyst protein), that was upregulated late in encystation, and that resembled the c...

Assembly of a protective cyst wall by Giardia is essential for the survival of the parasite outside the host intestine and for transmission among susceptible hosts. The structure of the G. intestinalis filamentous cyst wall was studied by chemical methods, mass spectrometry, and (1)H nuclear magnetic resonance spectroscopy. Isolated cyst wall material contains carbohydrate and protein in a rati...

Giardia duodenalis is a zoonotic protozoan parasite with public health importance worldwide. While articles about animal model infectivity have been published for G. duodenalis, the studies have used diverse protocols and parameters to evaluate the infectivity of this protozoan parasite. Hence, the objectives of this study were to (1) conduct a meta-analysis of published literature for cyst she...

Cholesterol and bile salts are relevant modulators of Giardia encystation. Although several molecules within signaling cascades have been identified, and changes in their expression observed during giardial encystation, their underlying interactions leading to expression of cyst wall markers (CWPs and precursors of the GalNAc homopolymer) are not well defined. Recent experimental data and the c...

Immunomagnetic separation (IMS) has been specified as a standard method for the measurement of Giardia under USEPA Method 1623. In this study, IMS was evaluated on the basis of recovery efficiencies for Giardia cysts under various IMS operation conditions. Significant change in recovery was observed by altering the debris ratio of water samples. Notably, cyst recovery efficiencies utilizing IMS...

Enteric protozoan parasites, which are spread by the fecal-oral route, are important causes of diarrhea (Giardia duodenalis) and amebic dysentery (Entamoeba histolytica). Cyst walls of Giardia and Entamoeba have a single layer composed of fibrils of β-1,3-linked GalNAc and β-1,4-linked GlcNAc (chitin), respectively. The goal here was to determine whether hand sanitizers that contain ethanol or ...

A wastewater tertiary treatment system based on membrane ultrafiltration and fed with secondary-treated municipal wastewater was evaluated for its Giardia cyst and Cryptosporidium oocyst removal efficiency. Giardia duodenalis (assemblages A and B) and Cryptosporidium parvum were identified in feed water but were found in filtered water only during occasional failure of the filtration system.

We report a method for detecting Giardia duodenalis cysts on lettuce, which we subsequently use to examine salad products for the presence of Giardia cysts and Cryptosporidium oocysts. The method is based on four basic steps: extraction of cysts from the foodstuffs, concentration of the extract and separation of the cysts from food materials, staining of the cysts to allow their visualization, ...

Giardia is a flagellated protozoan that resides in the upper small intestine of its vertebrate host and is the most common cause of defined waterborne diarrhoea worldwide. Giardia trophozoites undergo significant biological changes to survive outside the host by differentiating into infective cysts. Encystation is thus essential for transmission of the parasite among susceptible hosts. In the p...