Melatonin has immunomodulatory effects but very little is known about its influence in protozoan infections, such as Entamoeba histolytica, which causes amoebiasis, a disease with significant morbidity and mortality. In this study, we evaluated the effects of exogenous melatonin interference in experimental amoebiasis and on interactions between human blood cells and E. histolytica trophozoites.
The effect of melatonin was investigated in models of experimental amoebiasis in hamsters and rats by evaluating the area of necrosis induced by E. histolytica. The activity of melatonin on the interactions between leukocytes and amoebae was determined by examining leukophagocytosis. For in vitro tests, polymorphonuclear and mononuclear human blood leucocytes were incubated with E. histolytica trophozoites.
The areas of amoebic necrosis were significantly reduced in animals treated with melatonin. Melatonin treatment increased leukophagocytosis but was associated with a greater number of dead amoebae.
These results suggest that melatonin may play a beneficial role in the control of amoebic lesions, raising the possibility that this drug may be used as an adjuvant in anti-amoebic therapy.
Optimal conditions for carrying out the indirect haemagglutination test with sheep erythrocytes were studied using the microtitre system. The age of the erythrocytes, concentration of reagents, time and temperature of tanning, sensitization, and incubation are described with reference to replication of titres. Sera from patients with amoebic colitis were used to evaluate the test conditions.
In ancient days, Physicians having the comprehensive knowledge of Bhaishajya Kalpana, used to prepare the drugs themselves to treat their patients. So there was no doubt in obtaining genuine drug with desired therapeutic effect. But in recent years, the growing population and their life style, industrialization etc have forced physicians to depend on market preparations. As such we find the necessity of standardization of these preparations. The quality assessments of a drug, which is a chemical irrespective of the system is possible by ‘Thin Layer Chromatographic technique’ using known Chemical constituents as reference standards. A herbal preparation ‘Kutajarishta’, has been standardized by using this technique and the significance of the findings is discussed.
Amoebiasis is world wide in distribution and continues to be an important Public health problem. Intestinal amoebiasis may be present as dysentery, diarrhea or may stimulate other intra abdominal conditions. Clinical symptoms may not be seen in majority of patients, while amebic cysts are passed in the stool. This single-celled parasite is transmitted to humans via contaminated water and food. Amoebic dysentery can be accompanied by amebic infection of the liver and other organs. The present study was carried out to evaluate the changes in the circulating levels of neurohumors, their metabolizing enzymes and cortisol in these patients both before and after one month of chemotherapy. In the patients of amoebiasis the circulating acetylcholine (ACh), histamine, histaminase, cortisol, 5-Hydroxy tryptamine (serotonin) levels were significnatly enhanced with no change in the Dopamine-beta-hydroxylase (DBH) activity, while the activities of erythrocyte aceytylcholinesterase (AChE) and plasma Monoamine oxidase (MAO) were found decreased in comparison to normal healthy controls. After one month of treatment all the parameters reverted towards their control values, while the level of plasma histaminase remained still significantly high. The normal DBH activity reflects that there is no alteration in the circulating catecholamine levels. while the alteration in the levels of histamine, serotonin and cortisol may be due to the nonspecific response of the body to the stress of the disease and the parasitic infestation.
Amoebiasis; Acetylcholine; Cortisol; histamine; Histaminase
Amoebiasis is an important public health problem in developing countries. Entamoeba histolytica, the causative agent of amoebiasis, may develop resistance to nitroimidazoles, a group of drugs considered to be the most effective against this parasitic disease. Therefore, research on new drugs for the treatment of this common infection still constitutes an important therapeutic demand. In the present study we determined the effects of a carbamate derivative, ethyl 4-chlorophenylcarbamate (C4), on trophozoites of E. histolytica strain HM-1:IMSS. C4 was subject to various toxicity tests, including the determination of mutagenicity for bacterial DNA and changes in the enzymatic activities of eukaryotic cells. Genotoxicity studies were performed by the mutagenicity Ames test (plate incorporation and preincubation methods) with Salmonella enterica serovar Typhimurium, with or without metabolic activation produced by the S9 fraction of rat liver. C4 toxicity studies were performed by measuring enzymatic activity in eukaryotic cells by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-formazan test with Fischer 344 rat hepatocytes. C4 did not induce either frame-shift mutations in S. enterica serovar Typhimurium TA97 or TA98 or base pair substitutions in strains TA100 and TA102. The compound was not toxic for cultured rat hepatic cells. Trophozoites treated with 100 μg of C4 per ml were inhibited 97.88% at 48 h of culture; moreover, damage to the amoebae was also confirmed by electron microscopy. The antiamoebic activity of C4 was evaluated by using an in vivo model of amoebic liver abscess in hamsters. Doses of 75 and 100 mg/100 g of body weight reduced the extent of the amoebic liver abscess by 84 and 94%, respectively. These results justify further studies to clearly validate whether C4 is a new suitable antiamoebic drug.
A positive serological diagnosis of amoebiasis could be made by immunofluorescence in 66 of 78 established cases, taking a serum titre of 16 or higher as diagnostic: at this level there were no false positives among 94 control sera. The test is simple and may be carried out on amoebic smears stored for several months in 2-octanol. The serological activity is largely confined to the IgG immunoglobulin fraction and is specific for Entamoeba histolytica; cross reactions were not detected with other protozoa. Gel diffusion serological analysis permitted a positive diagnosis of amoebiasis in 60 of the 78 cases, and, combining this with the immunofluorescence test, raised the diagnostic score to 71 cases.
Pulmonary amoebiasis without liver involvement occurs sporadically as a result of haematogenous spread from a primary site, the colon. The case history is presented of a patient who developed superior vena cava syndrome due to a pulmonary amoebic abscess without liver involvement. He was initially suspected of having a neoplasm but a combination of tests including histological examination of the H&E stained excised tissue, immunofluorescence using anti-Entamoeba histolytica antibodies, and serology confirmed the diagnosis of amoebiasis. To our knowledge this is the first description of pulmonary amoebiasis presenting as superior vena cava syndrome.
Leaves of Codiaeum variegatum (“garden croton”) are used against bloody diarrhoea by local populations in Cameroon. This study aims to search for the active components from C. variegatum against Entamoeba histolytica, and thereby initiate the study of their mechanism of action. A bioassay-guided screening of the aqueous extracts from C. variegatum leaves and various fractions was carried out against trophozoites of E. histolytica axenic culture. We found that the anti-amoebic activity of extracts changed with respect to the collection criteria of leaves. Thereby, optimal conditions were defined for leaves' collection to maximise the anti-amoebic activity of the extracts. A fractionation process was performed, and we identified several sub-fractions (or isolated compounds) with significantly higher anti-amoebic activity compared to the unfractionated aqueous extract. Anti-amoebic activity of the most potent fraction was confirmed with the morphological characteristics of induced death in trophozoites, including cell rounding and lysis. Differential gene expression analysis using high-throughput RNA sequencing implies the potential mechanism of its anti-amoebic activity by targeting ceramide, a bioactive lipid involved in disturbance of biochemical processes within the cell membrane including differentiation, proliferation, cell growth arrest and apoptosis. Regulation of ceramide biosynthesis pathway as a target for anti-amoebic compounds is a novel finding which could be an alternative for drug development against E. histolytica.
Amoebiasis is a disease caused by a protozoan parasite, Entamoeba histolytica, with or without clinical symptoms. Humans are the only relevant host of this parasite, which mainly targets the large intestine and the liver. The current drug, metronidazole, has been successfully used against this parasite for several years. However, some reports have shown either parasite resistance or adverse effects due to its long term usage. Our study thereby pointed to alternative treatment of this infection by investigating the rational use of Codiaeum variegatum also referred as “garden croton” which is a medicinal plant used in Cameroon against bloody diarrhoea. We moved into the identification of the most efficient fraction of the aqueous extract of this plant, and initiated the characterization of the mechanism of action of this fraction. Upon treatment with the active fraction, parasite death occurs within two days through morphological changes such as cell membrane disorganization and cell destruction. More deeply, we found that components of the active fraction modify expression of genes involved in ceramide biosynthesis, a pathway responsible for cell death and growth inhibition. Our study therefore suggests a novel finding which could be further explored for screening of anti-amoebic drugs.
We compared the capability of rapid enzyme immunoassay (EIA) to detect antiamoebic antibodies during hepatic amoebiasis with those of indirect hemagglutination and latex agglutination. EIA is simple to perform and rapid (20 min) and does not require any special equipment (optical reading is sufficient). EIA of 143 sera (including 43 from patients with proven hepatic amoebic abscess, 33 from patients with other hepatic disorders and/or parasitic infections, and 67 from healthy individuals) yielded a specificity, a sensitivity, and positive and negative predictive values of 100, 93, 100, and 97.1, respectively. This test could thus be considered another valuable tool for the diagnosis of hepatic amoebiasis.
The clinical presentation of amoebic colitis are diverse. Amoebiasis is comparatively rare in the U.K. and, unless the clinician is aware of the condition, wrong diagnosis often leads to delay in appropriate treatment resulting in high mortality. Diagnosis rests on clinical suspicion, stool examination, sigmoidoscopy with rectal biopsy and serological tests. Amoebiasis is readily treatable and death from it should be very rare.
Patients with amoebiasis who receive steroid treatment may suffer adverse affects including acute amoebic dysentery and exacerbation of the amoebiasis. In some cases the presenting symptoms are initially misdiagnosed and steroids prescribed, which provokes fulminating progression of hepatic amoebiasis. Repeated stool examinations often yield negative results. Any patient being considered for treatment with corticosteroids who has lived in the tropics should be investigated for amoebiasis serologically and by repeated stool examination. Even after negative results the possibility of amoebiasis should be reconsidered if diarrhoea or fever develops during or after steroid treatment.
AIMS--To develop a rapid latex agglutination screening test for invasive amoebiasis. METHODS--The performance of an in-house latex agglutination test was compared with three standard serological techniques--the immunofluorescent antibody test (IFAT), the indirect haemagglutination test (IHA), and the cellulose acetate precipitin (CAP) test. Forty six sera were screened; 12 from negative controls; 10 sera from infections other than amoebiasis, and 24 sera from patients with luminal or extraluminal infection with Entamoeba histolytica. RESULTS--Strong positive latex agglutination reactions were observed, with 12 of 12 sera giving combined CAP positive, IFAT positive, and IHA positive results. These results are indicative of invasive amoebiasis. Twelve CAP negative, IFAT positive sera, and 10 of 12 IHA negative gave weak or negative agglutination reactions. One of 12 CAP negative, IFAT positive, and IHA positive sera gave a strong positive latex agglutination result; one with CAP negative, IFAT positive, and IHA positive sera gave a weak latex agglutination reaction. These results correlate with either treated amoebiasis or with the early stages of invasive amoebiasis for which the CAP test is known to have a lower sensitivity than the IFAT, but a higher specificity. No reactions were observed with 12 out of 12 CAP negative, IFAT negative, and IHA negative control sera and all 10 sera from other infections (two giardiasis, three schistosomiasis, three malaria, one filariasis). CONCLUSIONS--The latex agglutination test was a useful indicator test, paralleling the results obtained with standard serological techniques. It could also be a useful screening tool in the field.
Thoracic symptoms were noted in 38 (86%) out of 44 patients with hepatic amoebiasis and dominated the clinical picture in 4 (9%), causing dangerous delay in initiating appropriate treatment. Thoracic amoebiasis characteristically presents as a febrile illness with cough, chest pain, and point tenderness in an intercostal space or the right upper quadrant of the abdomen. Haemoptysis, diarrhoea, and dysentery are uncommon, occurring in approximately equal proportions (9%). The most important factor in clinical recognition is awareness of the possibility of the lesion. Chest radiography, serological tests, and therapeutic trials give corroborative evidence. In endemic areas thoracic amoebiasis should always be considered in the evaluation of obscure, especially right-sided, respiratory symptoms.
The clinical study records the clinical presentations of forty cases with amoebias and / or giardiasis including the efficacy of Kutaja (Holarrhena antidysenterica) in intestinal amoebiasis. E. H. Cyst passers also have symptoms like loose motions, constipation, flatulence, abdominal cramping, diminished appetite and mucus in stools. Patients with giardiasis have more tendency to diarrhoea and flatulence with no mucus in stools. 70 per cent good response was observed in E. H. Cyst passers when treated with Kutaja bark. Therefore, it appears that well known anti – diarrhoeal traditional herbal drug Kutaja, may be helpful to an extent in treating the amoebiasis. It will prove to be a very economic drug
Entamoeba infections primarily involve the gastrointestinal tract and, although rare in North America, are common in the developing world. Infections can range from asymptomatic to severe or fatal invasions of multiple organ systems. Most cases in North America involve first-generation immigrant populations and returning international travellers. It can be difficult to differentiate Entamoeba histolytica-associated colitis from inflammatory bowel disease and invasive bacterial dysentery. Moreover, specific tests for E histolytica infection are not readily available in many centres, and stool studies and sigmoidoscopy can miss cases. Following two case presentations, this review discusses several aspects of these types of infection and stresses the importance of keeping E histolytica-associated colitis in differential diagnoses.
Entamoeba histolytica infections of the gastrointestinal tract are common in the developing world but rare in North America. The authors present two cases: one involving an individual who had not travelled to an endemic area and another involving an individual who was born in Bulgaria. Both presented with severe abdominal pain and diarrhea. Endoscopic assessment revealed scattered colonic ulcerations and one patient was found to have a liver abscess on imaging. Stool ova and parasite studies were negative in both cases and both were diagnosed on review of colonic biopsies. On review of all Entamoeba cases in the Calgary Health Zone (Alberta), ova and parasite analysis found an average of 63.7 Entamoeba cases per year and a pathology database review revealed a total of seven cases of invasive E histolytica (2001 to 2011). Both patients responded well to antibiotic therapy. E histolytica should be considered in new-onset colitis, especially in individuals from endemic areas.
Amoebic colitis; Entamoeba histolytica; Extraintestinal abscesses
A new bicolored latex agglutination amoeba test (BLA) for detection of antibodies against Entamoeba histolytica was evaluated for its practicability and diagnostic sensitivity and specificity. BLA is rapid (5 min) and simple to perform. It requires only 20 microliters of a 1/3-diluted serum, 17 microliters of reagent, and a glass slide. Reading of the test is easy because a positive result shows a green spot with a red surrounding edge. This bicolored pattern is easily distinguishable from the negative test result, which shows a homogeneous dark-brown spot. By using serum samples from 348 individuals, BLA was compared with immunofluorescence assay, indirect hemagglutination, and counterimmunoelectrophoresis. Sensitivity, specificity, efficiency, and positive and negative predictive values of the four methods were almost identical. The results of this study indicate that BLA could be very useful both as a screening method for the diagnosis of invasive amoebiasis and for epidemiological purposes.
Acute Fulminant Necrotizing Amoebic Colitis is a rare complication of amoebiasis that is associated with high mortality. Only one to four such cases are seen per year in large hospitals of India, and only few such cases have been reported in the literature. The condition requires early diagnosis and surgical intervention. We recently cared for a patient who presented with acute abdomen with history of intermittent abdominal pain and diarrhea. Before presenting to our institution he was misdiagnosed as a case of inflammatory bowel disease and had been treated with steroids. On emergency exploration, extensive necrosis and multiple perforations in retroperitoneum involving entire colon were seen. Total colectomy with ileostomy was performed. Postoperative course was marked by septicaemia and multi-organ failure followed by death. This case report emphasizes the importance of early diagnosis and treatment of acute FAC, and associated high mortality.
The clinical, histopathological, and serological features of 35 homosexual men with infection with Entamoeba histolytica were studied and compared with a group of 35 non-infected homosexual men. Each isolate was of Zymodeme type I. Although there was no significant difference in the numbers of infected and non-infected men with gastrointestinal symptoms (48.6% and 28.6% respectively), the mean duration of symptoms was greater in with amoebiasis (p less than 0.05). The histology of the rectal mucosa was abnormal in 17 (63.0%) of the 27 men with amoebic infection only and in two (7.4%) of the 27 control subjects (p less than 0.001). Serum antibodies reactive with E. histolytica were not shown in any patient.
AIMS--To assess the reliability of the detection of erythrophagocytic amoebic trophozoites in stool samples in the diagnosis of dysentery associated with invasive Entamoeba histolytica. METHODS--Amoebic culture was carried out on single stool samples collected from patients from Mexico, Colombia, and Bangladesh. The stools had been examined by light microscopy. Amoebic dysentery was diagnosed when erythrophagocytic E histolytica trophozoites were observed in a case of bloody diarrhoea. E histolytica isolates were characterised by isoenzyme electrophoresis and results correlated with microscopical findings in stools. Statistical analysis was performed using the chi 2 test. RESULTS--Where erythrophagocytic amoebae had been observed in dysenteric stool specimens the E histolytica phenotype was invariably invasive (p < 0.0001). Observation of erythrophagocytic amoebae in dysentery is 100% specific and predictive of infection with invasive E histolytica. When amoebic culture-positive cases only are considered it is 96% sensitive. In this study E histolytica of zymodeme XIV was more commonly associated with amoebic dysentery than zymodeme II. There was no significant difference between the carriage rate of invasive and non-invasive E histolytica in non-dysenteric diarrhoea. Asymptomatic subjects carried non-invasive E histolytica more frequently than invasive E histolytica. Patients with non-amoebic dysentery, when shown to be infected with E histolytica, carried non-invasive strains (12%). CONCLUSIONS--Sensitivity and specificity of microscopical examination of a single stool specimen for diagnosing amoebic dysentery is very high; intestinal carriage of invasive E histolytica detected by culture is not necessarily an indication of active disease as patients with diarrhoea and asymptomatic subjects shed invasive and non-invasive E histolytica. There are possibly two subpopulations of invasive E histolytica with different pathogenic potential which can be differentiated by zymodeme analysis.
Lactobacillus plantarum is considered as a safe and effective probiotic microorganism. Among various sources of isolation, traditionally fermented foods are considered to be rich in Lactobacillus spp., which can be exploited for their probiotic attribute. Antibacterial property of L. plantarum has been demonstrated against various enteric pathogens in both in vitro and in vivo systems. This study was aimed at characterizing L. plantarum isolated from Kutajarista, an ayurvedic fermented biomedicine, and assessing its antagonistic property against a common enteropathogen Aeromonas veronii.
We report the isolation of L. plantarum (VR1) from Kutajarista, and efficacy of its cell free supernatant (CFS) in amelioration of cytotoxicity caused by Aeromonas veronii. On the part of probiotic attributes, VR1 was tolerant to pH 2, 0.3% bile salts and simulated gastric juice. Additionally, VR1 also exhibited adhesive property to human intestinal HT-29 cell line. Furthermore, CFS of VR1 was antibacterial to enteric pathogens like Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Aeromonas veronii and clinical isolates of P. aeruginosa and E. coli. Detailed study regarding the effect of VR1 CFS on A. veronii cytotoxicity showed a significant decrease in vacuole formation and detrimental cellular changes in Vero cells. On the other hand, A. veronii CFS caused disruption of tight junction proteins ZO-1 and actin in MDCK cell line, which was prevented by pre-incubation with CFS of VR1.
This is the first study to report isolation of L. plantarum (VR1) from Kutajarista and characterisation for its probiotic attributes. Our study demonstrates the antagonistic property of VR1 to A. veronii and effect of VR1 CFS in reduction of cellular damage caused by A. veronii in both Vero and MDCK cell lines.
Diagnosis of amoebic liver abscess (ALA) in patients on anti-amoebic drugs is difficult. There is scanty data on this issue using Entamoeba histolytica (E. histolytica) lectin antigen and polymerase chain reaction (PCR). We studied utility of lectin antigen, PCR, and IgG antibody in diagnosis of liver abscess in patients on anti-amoebic treatment. Liver aspirate of 200 patients, of which 170 had anti-amoebic drug prior to drainage, was tested for E. histolytica lectin antigen by (ELISA), PCR, bacterial culture, and serum IgG antibody by (ELISA). Classification of abscesses was based on result of anti-amoebic IgG antibody and bacterial culture, E. histolytica PCR and bacterial culture, and E. histolytica lectin antigen and bacterial culture.
Using anti-amoebic IgG antibody and bacterial culture, 136/200 (68.0%) were classified as ALA, 12/200 (6.0%) as pyogenic liver abscess (PLA), 29/200 (14.5%) as mixed infection, and 23/200 (11.5%) remained unclassified. Using amoebic PCR and bacterial culture 151/200 (75.5%) were classified as ALA, 25/200 (12.5%) as PLA, 16/200 (8.0%) as mixed infection, and 8/200 (4.0%) remained unclassified. With E. histolytica lectin antigen and bacterial culture, 22/200 (11.0%) patients were classified as ALA, 39/200 (19.5%) as PLA, 2/200 (1.0%) as mixed infection, and 137/200 (68.5%) remained unclassified.
E. histolytica lectin antigen was not suitable for classification of ALA patients who had prior anti-amoebic treatment. However, PCR may be used as alternative test to anti-amoebic antibody in diagnosis of ALA.
Entamoeba histolytica; Amoebiasis; Pyogenic liver abscess; Anti-amoebic IgG antibody
Amoebiasis continues to be a major cause of morbidity and mortality in children in developing countries. Entamoeba histolytica infections are commonly observed in tropical and subtropical regions of the world including Iran. In developed countries Entamoeba histolytica infections are commonly seen in travelers, recent immigrants, homosexual men, and inmates of institutions. The disease is more severe in the two extremes of life. This paper paper describes a four-month-old male infant with Entamoeba histolytica presenting initially with refusal of feeds, hyperactive bowel sound, vomiting, and diarrhea. A fecal sample was positive for Entamoeba histolytica by Lugol's iodine solution and the concentration technique. He was successfully treated with metronidazole for 5 days. This case illustrates that Entamoeba species could be pathogenic in young infant; therefore, awareness of the infection, aggressive approach to diagnosis, and early initiation of treatment continue to be critical component of infection control.
Here we present an interesting and extremely rare case of a 66 year old male who developed a colocutaneous fistula secondary to amoebiasis. The patient presented with an acute history of right lower abdominal pain, weight loss and a palpable mass. A CT scan demonstrated a fluid filled cavity in the right iliac fossa consistent with an appendiceal abscess which was drained under radiological guidance. However, following drainage his symptoms remained requiring open surgical drainage, and a controlled caecostomy was performed due to a small caecal perforation. Despite appropriate conservative therapy he failed to progress, and developed localised sepsis in the right iliac fossa with a colocutaneous fistula, requiring a formal right hemicolectomy. The histological examination confirmed the presence of abundant trophozoites of Entamoeba histolytica.
We highlight the fact that in the modern age of immigration and long distance travel, it will become increasingly likely that the so-called ‘tropical’ diseases will present throughout the world. This case also highlights the need to keep an open mind in cases that do not progress as expected, and to react accordingly to any unusual developments.
Colocutaneous fistula; Appendicular abscess; Amoebic dysentery; Amoebiasis
In accordance with the 1997 documents of the World Health Organization (WHO), amoebiasis is defined as the infection by the protozoan parasite Entamoeba histolytica with or without clinical manifestations. The only known natural host of E. histolytica is the human with the large intestine as major target organ. This parasite has a very simple life cycle in which the infective form is the cyst, considered a resistant form of parasite: The asymptomatic cyst passers and the intestinal amoebiasis patients are the transmitters; they excrete cysts in their feces, which can contaminate food and water sources. E. histolytica sensu stricto is the potentially pathogenic species and E. dispar is a commensal non-pathogenic Entamoeba. Both species are biochemical, immunological and genetically distinct. The knowledge of both species with different pathogenic phenotypes comes from a large scientific debate during the second half of the 20th century, which gave place to the rapid development of diagnostics technology based on molecular and immunological strategies. During the last ten years, knowledge of the new epidemiology of amoebiasis in different geographic endemic and non-endemic areas has been obtained by applying mostly molecular techniques. In the present work we highlight novelties on human infection and the disease that can help the general physician from both endemic and non-endemic countries in their medical practice, particularly, now that emigration is undoubtedly a global phenomenon that is modifying the previous geography of infectious diseases worldwide.
Amoebiasis; Diagnosis; Treatment
A small series of patients with amoebiasis presenting to the surgical service in Seychelles is described. The varied nature of the symptomatology indicates that this may be a local pattern of the disease process. The value of specific clinical features and the use of a therapeutic trial for diagnosis is emphasised. The features of common 'Third-World' diseases should be well known to all surgeons wherever they practise in view of the rapidity with which people can now travel from country to country.