Entamoeba histolytica treatment
- Extraintestinal infections include liver abscesses. Diagnosis is by identifying E. histolytica in stool specimens or by serologic tests. Treatment for symptomatic disease is with metronidazole or tinidazole followed by paromomycin or another drug active against cysts in the lumen of the colon.
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May 28, 2021 · There are a number of effective medications. Generally several antibiotics are available to treat Entamoeba histolytica. The infected individual will be treated with only one antibiotic if the E. histolytica infection has not made the person sick and most likely be prescribed with two antibiotics if the person has been feeling sick.
The treatment period was extended in patients with stools positive for Entamoeba histolytica on the day following the last treatment day. Fifty-six patients, 29 on tinidazole and 27 on metronidazole, completed the trial as per the protocol. Twenty-eight patients (96.5%) on tinidazole and 15 (55.5%) on metronidazole were cured.
- B Swami, D Lavakusulu, C S Devi
Some useful measures include: Washing your hands before eating. When traveling abroad, stick to bottled water or boil the local water 20 minutes before drinking it. Avoid drinking water from fountains. Elude milk, cheese, and other unpasteurized products. Avoid eating food from informal food ...
A study in Egypt showed treatment with a 3-day course of nitazoxanide was effective (94% efficacy) compared to placebo in the treatment of intestinal amoebiasis. A total of 94% of patients treated with nitazoxanide were free of Entamoeba histolytica in two post-treatment stool specimens compared with only 43% of patients receiving placebo.
Nov 19, 2020 · If you have no symptoms but are found to have E. histolytica in a stool (faeces) specimen, it is usually advised that you should be treated with medication to kill the parasite. The medicine diloxanide furoate is commonly used. Treatment is advised because you can still pass on the infection to others even if you have no symptoms.
- Dr Laurence Knott
- Clinical Manifestations
- Laboratory Diagnosis
- Susceptibility in Vitro and in Vivo
- Antiparasitic Therapy
- Adjunctive Therapy
- Endpoints For Monitoring Therapy
Life cycle Entamoeba histolytica is a protozoan parasite that accounts for an estimated 100,000 annual deaths (71). Infection ranges from asymptomatic colonization of the large bowel to severe invasive intestinal and extra-intestinal disease. The parasite life cycle is relatively simple: humans orally ingest the cyst form from contaminated sources, excystation to the trophozoite form occurs in the small bowel, then the trophozoite either colonizes or invades the large bowel. When the trophozoite encysts the life cycle is complete and the organism can be transmitted (20).
The epidemiology of Entamoeba histolytica has been complicated by the mid-1990's redescription of E. histolytica into two species: E. histolytica, which is pathogenic, and E. dispar, which is not (71). Further molecular studies have identified a third species, E. moshkovskii, that also tends to be non-pathogenic (2). The bulk of previous studies on the prevalence of E. histolytica were based on stool microscopy, which is of low sensitivity and specificity and cannot distinguish E. histolytica cysts or trophozoites from E. dispar or E. moshkovskii. Thus the conclusions that 10% of the world's population is infected with E. histolytica is probably an overestimate (59). Serologic studies are more reliable, since only E. histolytica infection generates a serum antibody response (54) and these suggest that up to 8.4% of persons in endemic countries have been exposed (8). In developed countries, populations at risk for E. histolytica infection include returned travelers or expatriates and...
Infection with E. histolytica may be asymptomatic or cause intestinal or extraintestinal disease. Asymptomatic infection with E. histolytica but not E. dispar is associated with a positive serum anti-amebic antibody and, frequently, a positive stool antigen test. Clinical syndromes associated with intestinal E. histolytica disease include diarrhea, acute rectocolitis (dysentery), fulminant colitis (acute necrotizing colitis) with perforation, toxic megacolon, chronic nondysenteric colitis, am...
Amebic liver abscess is the most common extraintestinal manifestation of amebiasis and is 10 times more common in adult men despite an approximately equal sex distribution of colonic amebic disease. Approximately 80% of patients manifest relatively quickly, typically within 2 to 4 weeks (20). However, 95% of travelers develop liver abscess within 2 to 5 months (median 3 months) after leaving the endemic area. The acute symptoms include fever and a constant, dull, aching pain in the right uppe...
When the diagnosis of asymptomatic intestinal infection with E. histolytica is sought (e.g., for epidemiologic studies, in a traveler returning from a highly endemic area, or when E. histolytica/E. dispar trophozoites or cysts are seen incidentally on stool microscopy), one should ideally use fecal antigen detection assays (66). There are presently several commercially available antigen kits for detecting Entamoeba (TechLab E. histolytica II, Blacksburg, VA; Ridascreen Entamoeba, R-Biopharm, Germany; Triage Micro Parasite Panel, Biosite Diagnostics, Inc., San Diego CA; ProSpecT E. histolytica, Remel Inc., Lenexa, KS; CELISA Path, Cellabs, Brookvale, Australia). Unfortunately, these tests require fresh (not formalin-preserved) stool for analysis, and only the TechLab and Cellabs kits report being specific for E. histolytica not E. dispar. Stool PCR is a promising new technique. Performing isoenzyme analysis on trophozoites cultured from stool is another possible but laborious and imp...
The parasite is appropriately named “histolytica” for its cellular destructive nature. The trophozoite initiates infection with adherence to colonic mucin and epithelial cells via a Gal/GalNAc lectin (46). The serine-richE. histolytica protein may also play a role in adherence, as antibodies to SREHP partially inhibit adherence in vitro (60). Upon Entamoeba-cell co-culture experiments, cells undergo morphologic and DNA degradative changes consistent with apoptosis as well as necrosis (52). The mechanism of apoptosis appears to involve direct activation of downstream caspases including caspase 3 (25). Entamoeba then engulf apoptotic corpses, and this feature correlates with virulence in vitro (7). Other pathogenic events are mediated through the secretion of amebic proteinases (28, 53). Recent work on the host response to E. histolytica infection has brought insight into mechanisms of protection. In mice neutrophils and Natural Killer T cells afford some protection against intestinal...
The cyst form of the parasite cannot be cultured in vitro, so there are no in vitro cysticidal data available. Axenic growth of E. histolytica trophozoites was developed in 1968 (12) and has allowed for limited in vitroefficacy studies for relevant drugs (see Table 1). Acquired drug resistance to E. histolytica has historically been extremely difficult to develop in vitro, presumably because the metronidazole-activating enzyme pyruvate ferredoxin oxidoreductase is required for Entamoeba metabolism.
Asymptomatic Intestinal Colonization
There are at least three classes of drugs that have shown efficacy in clinical trials for asymptomatic intestinal colonization: dichloracetanilide derivatives, oral aminoglycosides, and 5-hydroxyquinolines. The specific agents include diloxanide furoate (Furamide), paromomycin (Humatin), and iodoquinol (Yodoxin, also known as diiodohydroxyquin) (see Table 2). All have a large worldwide experience. All have poor gastrointestinal absorption, which allows high luminal concentrations but renders...
The mainstay of therapy for amebic colitis since the 1960s has been the nitroimidazoles, in particular metronidazole (Flagyl) and tinidazole (Fazigyn) (see Table 2). Powell and coworkers performed the first clinical trial of metronidazole in patients with acute amebic dysentery (diagnosis made by the presence of hematophagous E. histolytica in stools and rectal biopsies) which demonstrated the superiority of 800 mg tid given for 10 days (48). Lower doses were less effective but subsequent stu...
The initial amebic colitis trials also included groups of "not severely ill patients" with amebic liver abscess. Liver abscess was found to be in general more responsive than colitis, with cure in all 210 patients regardless of the regimen. However because recovery was perceptibly slower in the lower dose (200 mg po tid) groups and single dose therapy has been associated with a 6% failure rate (32) we recommend the standard high dose of metronidazole for 10 days or tinidazole for 5 days (22)....
The rate of rupture of liver abscess appears to be high, on the order of 15-22% (38, 41). Rupture occurs most commonly into the thoracic or peritoneal cavity and less commonly into the pericardium or bowel. Any rupture is a high-mortality event (6-30%), particularly if into the pericardium (1). Therapy for rupture into accessible areas has traditionally included percutaneous or open drainage and if possible liver drainage as well. Some ruptures into the pleura have improved with metronidazole therapy alone. Intravenous metronidazole has been used successfully in the rupture setting (16). Given the high mortality of abscess rupture, the issue of when to prophylactically drain an abscess arises. One study found that percutaneous aspiration of amebic liver abscess with intralesional antibiotics led to faster resolution of pain than medical therapy or open drainage (13). However other studies indicate routine drainage of amebic liver abscess has conferred no clinical benefit over antibi...
At present there are no specific endpoints for monitoring amebic colitis or liver abscess patients other than clinical improvement. Provided serum antigen tests become more widespread this should become a laboratory test worth following. Patients with liver abscess should respond rapidly with therapy.
There are no commercially available vaccines against amebiasis, but the adherence lectin and the SREHP protein are promising candidates in animal systems.
There are a number of effective medications. Generally several antibiotics are available to treat Entamoeba histolytica. The infected individual will be treated with only one antibiotic if the E. histolytica infection has not made the person sick and most likely be prescribed with two antibiotics if the person has been feeling sick.
May 26, 2021 · What are amebiasis symptoms and signs? Early symptoms (in about 1-4 weeks) include loose stools and mild abdominal cramping. If the disease progresses, frequent, watery, and/or bloody stools with severe abdominal cramping (termed amoebic dysentery) may occur. If the trophozoites reach the intestinal ...