Answers
John D Firth, Professor Ian Gilmore in MRCP Part 2 Self-Assessment, 2018
Giardia lamblia is a very common intestinal parasite and a frequent cause of diarrhoeal illness throughout the world. Although water remains the most common mode of transmission, there has been an increase in the number of person-to-person cases, especially related to children, as well as an increase in food-borne cases. Chronic diarrhoea and malabsorption are seen with persistent infection and since treatment is simple and effective, diagnosis by duodenal biopsy is important. New antigen detection tests for stool may ultimately replace histology in some situations. The greatest clinical experience in treatment 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 do likewise.
Giardia outbreaks on Ship
Meera Chand, John Holton in Case Studies in Infection Control, 2018
The gut of infected humans and both wild and domestic animals can act as a reservoir. Giardia can be differentiated based on the host of origin, for example, G. lamblia in humans, G. muris in mice, G. agilis in amphibians, and G. psittaci in parakeets. Although G. lamblia has been found in cats, dogs, cows, sheep, and beavers, many genotypes found in these animals are not found in human isolates, suggestive of a relatively low zoonotic potential. In some areas, however, nearly all domestic cattle may become infected, and there has been a documented waterborne outbreak linked to surface contamination of unprotected water resources by beavers in Canada. Food-borne transmission of Giardia in commercial food establishments is also recognized, with the potential to cause outbreaks.
Facilitating Successful International Adoptions
Beth P. Velde, Peggy Prince Wittman in Community Occupational Therapy Education and Practice, 2012
Medical conditions that are commonly seen in international adoptees (Aronson, 2000) include chronic upper respiratory or ear infections, diarrhea, vomiting, impetigo, scabies or lice, diaper rash, feeding problems, or failure to thrive. Additional concerns include Hepatitis B, Tuberculosis, intestinal parasites, Hepatitis C and nutritional disorders such as rickets and iron-deficiency anemia. Children may also experience transitional depression when they first meet their new parents if they have left caregivers who have developed relationships with them. Parents should be advised to tell their pediatricians that their child might likely have intestinal parasites, which are common in international adoptees, and to have them checked for their presence. The most common form of intestinal parasites is Giardia, and parents need to be alerted that worms may be passed in the stool for months to years after arrival and treatment (Aronson, 2000). Although most parasites are not transmitted from person to person, Giardia is transmitted and may result in discomfort for family members.
Novel therapeutic opportunities for Toxoplasma gondii, Trichomonas vaginalis, and Giardia intestinalis infections
Published in Expert Opinion on Therapeutic Patents, 2023
Francesca Arrighi, Arianna Granese, Paola Chimenti, Paolo Guglielmi
Giardia intestinalis (syn., G. lamblia, G. duodenalis) is, similar to T. vaginalis, a flagellate protozoan involved in the insurgence of intestinal infection called giardiasis [32]. Its life cycle includes trophozoite and cystic forms. After ingestion of giardia cysts, typically via contaminated food or water or via the fecal-oral route, they direct to the stomach, where host proteases and acidic pH weaken cyst walls beginning the excystation, that is complete in the upper small intestine [33]. The released vegetative trophozoites divide by binary fission and attach to the small intestinal lumen epithelium via a ventral adhesive disk. The completion of life cycle is reached when trophozoites, after detachment, move along the GI tract where they are exposed to bile, and initiate encystation to create new cysts that are excreted into the environment [34]. Giardia intestinalis infection can occur without symptoms or exhibiting acute watery diarrhea, nausea, epigastric pain, and weight loss [32].
Persistent diarrhoea: current knowledge and novel concepts
Published in Paediatrics and International Child Health, 2019
Robert H. J. Bandsma, Kamran Sadiq, Zulfiqar A. Bhutta
A number of pathogens have been identified specifically as causing PD. However, debate remains around the association of specific bacterial, viral and parasitic infections with persistent and chronic diarrhoea; the latter defined as diarrhoea lasting more than 4 weeks. In a cohort of children in Iran, cryptosporidium was associated with persistent rather than acute diarrhoea [24]. Protozoa were found in 35% and helminthic infections in 25% of children with PD in Nepal [25]. In immunocompromised children specifically, intestinal parasites are commonly implicated pathogens in the causation of PD. However, a systematic review of children in LMIC found no evidence of a particular pathogen being associated with PD, with the exception of all enteropathogenic Escherichia coli [26]. A recent large multicentre study only found a significant association with prolonged diarrhoea (>7 days) and enterotoxigenic E. coli, astrovirus, cryptosporidium and shigella species in the first year of life and shigella and astrovirus in the second year of life. There was no association with other pathogens, including giardia with PD in young children [27].
Transient elevation of anti-transglutaminase and anti-endomysium antibodies in Giardia infection
Published in Scandinavian Journal of Gastroenterology, 2018
Kurt Hanevik, Elisabeth Wik, Nina Langeland, Trygve Hausken
One hundred and twenty-four patients with persisting abdominal symptoms after a waterborne Giardia outbreak in autumn 2004 were examined at Haukeland University hospital between January 2005 and March 2006. All had been diagnosed with giardiasis by fecal microscopy requested by their general practitioner, and treated one or more times with metronidazole during the acute illness. At the time of examination in the hospital 3–15 months after acute illness, persisting Giardia infection were found in 40 (32.3%) patients, and 34 (85%) of these also had duodenal inflammation. In the remaining 82 patients’ duodenal inflammation was also found in 23 (28%) patients who had become Giardia negative at the time of endoscopic investigation and blood sampling [9]. Giardia microscopy results were later verified with a sensitive Giardia PCR [10]. Endoscopy with duodenal biopsy, and measurement of serum tTG IgA (ELISA test anti-HuTransG, Generic assays GmbH, Dahlowitz, Germany (relative OD-units, with values >20 U/mL considered pathological)) and EMA IgA (immunofluorescence method with monkey esophagus (Biosystems SA, Barcelona, Spain) with FITC-conjugated IgA (Inova diagnostics Inc, San Diego, CA), results given as positive or negative) was part of the routine workup. Measurement of fecal calprotectin (mg/kg) was done by ELISA fhiCal Test (NovaTecImmundiagnostica GmbH, Germany), pathological when >50mg/kg. Histopathologic assessment of duodenal biopsies was performed, and particular focus was given to the number of intraepithelial lymphocytes (IEL; counted per 100 enterocytes) and presence of villous atrophy. Combined villous atrophy and increased IEL were graded according to modified Marsh classification [11,12]. Serum levels of IgA (normal values 0.2–5.1 g/L) were measured to exclude selective IgA deficiency.
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