Common Parasitic Cause Research Articles

A Review: Natural and Synthetic Compounds Targeting Entamoeba histolytica and Its Biological Membrane.

Amoebiasis is the third most common parasitic cause of morbidity and mortality, particularly in countries with poor hygienic settings in central and south America, Africa, and India. This disease is caused by a protozoan parasite, namely Entamoeba histolytica, which infects approximately 50 million people worldwide, resulting in 70,000 deaths every year. Since the 1960s, E. histolytica infection has been successfully treated with metronidazole. However, there are drawbacks to metronidazole therapy: the side effects, duration of treatment, and need for additional drugs to prevent transmission. Previous interdisciplinary studies, including biophysics, bioinformatics, chemistry, and, more recently, lipidomics studies, have increased biomembranes’ publicity. The biological membranes are comprised of a mixture of membrane and cytosolic proteins. They work hand in hand mainly at the membrane part. They act as dedicated platforms for a whole range of cellular processes, such as cell proliferation, adhesion, migration, and intracellular trafficking, thus are appealing targets for drug treatment. Therefore, this review aims to observe the updated trend of the research regarding the biological membranes of E. histolytica from 2015 to 2021, which may help further research regarding the drug targeting the biological membrane.

Enhanced detection of Giardia duodenalis mixed assemblage infections in pre-weaned dairy calves using next generation sequencing

Giardia duodenalis is one of the most common parasitic causes of gastrointestinal illness in humans worldwide with widespread infections in mammalian hosts. It frequently infects cattle, producing a high number of cysts. Cattle can harbor both host-adapted assemblage E and human pathogenic assemblages A and B. Previous studies have demonstrated that conventional molecular methods lack the sensitivity required for detecting mixed infections and that the occurrence of mixed infections in cattle are likely underestimated. To investigate the presence of mixed assemblage infections in cattle, 2539 pre-weaned dairy calves from the United Stated were screened for the presence of G. duodenalis using molecular tools. Next generation amplicon sequencing (NGS) was then performed for a subset of around 30% of positive samples (n = 314) and the ability of NGS and Sanger sequencing to detect mixed assemblage infections was compared. The overall prevalence of G. duodenalis in pre-weaned dairy calves in the sample using PCR was high (1013/2539; 39.9%). Molecular genotyping identified only assemblage A and E, with assemblage E as the predominant assemblage. Out of the 314 samples examined by both Sanger and NGS, 9 samples (2.9%) were identified as mixed A/E infections by Sanger while NGS identified 56 samples (17.8%), which was six-times more mixed infections compared with Sanger sequencing. NGS demonstrated superior sensitivity to Sanger in detecting assemblages present in low abundances. The percentage of mixed A/E infections found in the sampled dairy calves was higher than was hypothesized using values from the literature. This underestimation could be present in the wider cattle population as well, though further exploration would be needed to verify that claim. These findings highlight the advantages of NGS application in molecular epidemiological studies of Giardia. To better understand Giardia epidemiology, establish routes of transmission, and assess the potential role of cattle and other animals as a source of environmental contamination with zoonotic assemblages it is necessary to uncover mixed assemblage infections.

In-silico prediction and modeling of the Entamoeba histolytica proteins: Serine-rich Entamoeba histolytica protein and 29kDa Cysteine-rich protease.

BackgroundAmoebiasis is the third most common parasitic cause of morbidity and mortality, particularly in countries with poor hygienic settings. There exists an ambiguity in the diagnosis of amoebiasis, and hence there arises a necessity for a better diagnostic approach. Serine-rich Entamoeba histolyticaprotein (SREHP), peroxiredoxin and Gal/GalNAc lectin are pivotal in E. histolyticavirulence and are extensively studied as diagnostic and vaccine targets. For elucidating the cellular function of these proteins, details regarding their respective quaternary structures are essential. However, studies in this aspect are scant. Hence, this study was carried out to predict the structure of these target proteins and characterize them structurally as well as functionally using appropriate in-silicomethods.MethodsThe amino acid sequences of the proteins were retrieved from National Centre for Biotechnology Information database and aligned using ClustalW. Bioinformatic tools were employed in the secondary structure and tertiary structure prediction. The predicted structure was validated, and final refinement was carried out.ResultsThe protein structures predicted by i-TASSER were found to be more accurate than Phyre2 based on the validation using SAVES server. The prediction suggests SREHP to be an extracellular protein, peroxiredoxin a peripheral membrane protein while Gal/GalNAc lectin was found to be a cell-wall protein. Signal peptides were found in the amino-acid sequences of SREHP and Gal/GalNAc lectin, whereas they were not present in the peroxiredoxin sequence. Gal/GalNAc lectin showed better antigenicity than the other two proteins studied. All the three proteins exhibited similarity in their structures and were mostly composed of loops.DiscussionThe structures of SREHP and peroxiredoxin were predicted successfully, while the structure of Gal/GalNAc lectin could not be predicted as it was a complex protein composed of sub-units. Also, this protein showed less similarity with the available structural homologs. The quaternary structures of SREHP and peroxiredoxin predicted from this study would provide better structural and functional insights into these proteins and may aid in development of newer diagnostic assays or enhancement of the available treatment modalities.

Spectrum of epilepsy in Neurocysticercosis

Introduction: Neurocysticercosis (NCC) is one of the most common parasitic cause of neurological disease in developing countries. NCC is the infestation of the central nervous system with the larvae of pork tapeworm, Taenia solium. It is endemic in South Asia, Africa, and Latin America. Due to increasing international travel and immigration, NCC is no more a health issue limited to the developing countries but also to the rest of world. Material and methods: A total of 70 patients of seizures presenting with ring enhancing lesion in CT scan of brain suggestive of neurocysticercosis, attending outpatient department or admitted in wards of Medicine Department of S.R.N. Hospital. A detailed seizure history as well as neurological examination was done according to the working proforma. Results: Maximum number of patients 34(48.57%) were presented with simple partial seizures with secondary generalization. Generalized tonic-clonic seizure was present in 22 patient (31.43%) patients. Simple partial seizure without secondary generalization was presented in 12 patients (17.14%). Two patients (2.86%) were presented with complex partial seizure. Conclusion: Neurocysticercosis is more common in young, rural population and in lower socioeconomic class. Vegetarians were significantly more affected than non-vegetarians which suggest other mode of transmission. By combining hygiene education and better sanitation, we will interrupt or reduce the cycle of direct person-to-person transmission. Thus, probably we will succeed to reduce the burden of disease from the society.

Giardia lamblia infection increases risk of chronic gastrointestinal disorders.

Background Giardia lamblia is a common parasitic cause of infectious gastroenteritis in the United States and the world and may be linked to an increased risk of chronic gastrointestinal (GI) disorders. We sought to assess the risk of several chronic GI disorders following Giardia infection among active duty US military personnel.MethodsThis study was designed as a retrospective cohort study in which active duty military personnel with documented G. lamblia infection were assessed for the subsequent risk of developing a chronic GI disorder including irritable bowel syndrome (IBS), dyspepsia and gastroesophageal reflux disease (GERD). Post-giardia chronic GI disorder risk was compared to risk in uninfected personnel matched on several demographic characteristics and medical encounter information. Data were obtained from the Defense Medical Surveillance System and exposures (1998–2009) with outcomes identified based on documented medical encounters with specific medical billing codes. Modified Poisson regression was used to evaluate the relationship between G. lamblia infection and chronic GI disorders.ResultsA total of 80 Giardia cases were identified for an estimated incidence of 0.55 cases per 100,000 person-years. Cases were matched to 294 unexposed subjects. After adjusting for important covariates, there was an increased risk of IBS (relative risk: 2.1, p = 0.03) associated with antecedent Giardia infection.ConclusionThese data add to a growing body of literature and demonstrate an increased risk of IBS after infection with G. lamblia.

Etiology of bacterial and parasitological pediatric diarrhoea in a tertiary care hospital

Background : Before starting to discuss about Diarrhoea, we have to remember diarrhoea is one of the main causes of morbidity and mortality in children. Aims and Objectives : The aim of this study was to determine the prevalence of intestinal parasitic and bacterial infections as cause of childhood diarrhoea. Materials and Methods : During the study period, a total of 116 stool samples were collected and processed. Examined grossly and microscopically for presence of ova/cyst. They were also cultured on MacConkey agar and E. coli isolated were identified by standard biochemical tests.Results : Out of 116 stools samples, Entamoeba histolytica (63.33%) and Giardia lamblia (23.33%) were more common parasitic cause diarrhoea among children by either ova or cyst. E.coli (74.13%) was common bacterial cause of diarrhoea among children. E. coli isolated in pure culture and sent for sero typing to Central Research Institute (CRI), Kasauli. Maximum percent were found to be pathogenic Escherichia coli i.e. EPEC 22.5%. Conclusion : According to the result, the most common cause of bacterial diarrhoea is E.coli. EPEC were more prevalent followed by EHEC. Thus, macroscopic and microscopic stool examinations as well as culture were important for finding out the course of diarrhoea in childhood.Asian Journal of Medical Sciences Vol. 7(3) 2016 54-57

Giardia spp. Are Commonly Found in Mixed Assemblages in Surface Water, as Revealed by Molecular and Whole-Genome Characterization.

Giardia is the most common parasitic cause of gastrointestinal infections worldwide, with transmission through surface water playing an important role in various parts of the world. Giardia duodenalis (synonyms: G. intestinalis and G. lamblia), a multispecies complex, has two zoonotic subtypes, assemblages A and B. When British Columbia (BC), a western Canadian province, experienced several waterborne giardiasis outbreaks due to unfiltered surface drinking water in the late 1980s, collection of isolates from surface water, as well as from humans and beavers (Castor canadensis), throughout the province was carried out. To better understand Giardia in surface water, 71 isolates, including 29 from raw surface water samples, 29 from human giardiasis cases, and 13 from beavers in watersheds from this historical library were characterized by PCR. Study isolates also included isolates from waterborne giardiasis outbreaks. Both assemblages A and B were identified in surface water, human, and beavers samples, including a mixture of both assemblages A and B in waterborne outbreaks. PCR results were confirmed by whole-genome sequencing (WGS) for one waterborne outbreak and supported the clustering of human, water, and beaver isolates within both assemblages. We concluded that contamination of surface water by Giardia is complex, that the majority of our surface water isolates were assemblage B, and that both assemblages A and B may cause waterborne outbreaks. The higher-resolution data provided by WGS warrants further study to better understand the spread of Giardia.

Laboratory methods of identification of Entamoeba histolytica and its differentiation from look-alike Entamoeba spp.

Entamoeba histolytica, the causative agent of intestinal and extraintestinal amebiasis, is a common parasitic cause of significant morbidity and mortality in the developing countries. Hence, early detection and differentiation of pathogenic E. histolytica from nonpathogenic/commensal Entamoeba spp (Entamoeba dispar/Entamoeba moshkovskii/Entamoeba bangladeshi) plays a crucial role in clinical management of patients with amebiasis. Most diagnostic tests currently available do not reliably differentiate between the species of Entamoeba and are less sensitive, cumbersome to perform. Molecular-based methods are highly sensitive, easy to perform and differentiates the pathogenic Entamoeba from nonpathogenic species, serving the criteria for an ideal diagnostic test for amebiasis. Recently, microarray technology has been found to be a promising tool for the diagnostic and epidemiological evaluation of amebiasis.

Prevalence of Intestinal Parasitic and Bacterial Pathogens in Diarrhoeal and Non-diarroeal Human Stools from Vhembe District, South Africa

In the present study, a cross-sectional survey of intestinal parasitic and bacterial infections in relation to diarrhoea in Vhembe district and the antimicrobial susceptibility profiles of isolated bacterial pathogens was conducted. Stool samples were collected from 528 patients attending major public hospitals and 295 children attending two public primary schools and were analyzed by standard microbiological and parasitological techniques. Entamoeba histolytica/E. dispar (34.2%) and Cryptosporidium spp. (25.5%) were the most common parasitic causes of diarrhoea among the hospital attendees while Giardia lamblia (12.8%) was the most common cause of diarrhoea among the primary school children (p < 0.05). Schistosoma mansoni (14.4%) was more common in non-diarrhoeal samples at both hospitals (16.9%) and schools (17.6%). Campylobacter spp. (24.9%), Aeromonas spp. (20.8%), and Shigella spp. (8.5%) were the most common bacterial causes of diarrhoea among the hospital attendees while Campylobacter (12.8%) and Aeromonas spp. (12.8%) were most common in diarrhoeal samples from school children. Vibrio spp. was less common (3% in the hospitals) and were all associated with diarrhoea. Antimicrobial resistance was common among the bacterial isolates but ceftriaxone (91%) and ciprofloxacin (88.6%) showed stronger activities against all the organisms. The present study has demonstrated that E. histolytica/dispar, Cryptosporidium, Giardia, and Cyclospora are common parasitic causes of diarrhoea in Vhembe district while Campylobacter spp. and Aeromonas are the most common bacterial causes of diarrhoea in Vhembe district of South Africa.

Ameboma

61 Hispanic male with a history of hypercholestorolemia was referred to our clinic for a screening colonoscopy. He denied any complaints of weight loss, diarrhea, abdominal pain, hematochezia, melena fever, chills or fatigue. He was originally from South America, but had been in the U.S. for over five years. Our patient had no abnormal labaratory findings. On colonoscopy he was found to have a 2 cm ulcerated, friable flat mass with exudate in the ascending colon just outside the cecum. Histology revealed an ameboma which was described as severe active chronic inflammation with an exudate fragment showing trophozoites with erythrophagocytosis. The patient was treated with 10 days of metronidazole followed by 10 days of paromomycin. Intestinal amebiasis is caused by the protozoan Entamoeba Hystolytica. Worldwide 30–50 million symptomatic infections occur. It is the third most common parasitic cause of death. In the United states most of the cases are seen in immigrants from developing countries and travelers. Infection begins with ingestion of cysts from fecally contaminated water or food. Excystation occurs in the small bowel where trophozoites emerge. Ninety percent of patients colonized by E. Hystolytica spontaneously clear the infection by one year. Most patients are asymptomatic, however invasive intestinal amebiasis may mimic inflammatory bowel disease, malignancy and malsbsorptive illnesses. Extraintestinal manifestations are uncommon. They include liver abscesses, pleuropulmonary disease, cerebritis and pericarditis. Diagnosis is made by serologic and stool examinations.Microscopic examination of the stool has a low sensitivity 30–60%. A high false positive rate exists secondary to non pathogenic entamoebas which are morphologically identical to and more common then entamoeba hystolytica.ELISA stool antigen test which detects adherence lectin antigen has a sensitivity of 87% and a specificity of greater than than 90%. Seum antibody tests are most useful for extraintestinal disease when organisms are not found in the stool. Antibodies are detectable by the first week of infection and may persist for years. Up to 25% of uninfected patients in endemic regions are positive. An Ameboma is an unususual manifestation of entamoeba hystolytica. In immigrants from developing countries with atypical colonic masses one must consider entamoeba hystolytica as part of their differential diagnosis.

Nematode infections of the eye: toxocariasis, onchocerciasis, diffuse unilateral subacute neuroretinitis, and cysticercosis.

Nematode infections of the eye are common in different parts of the world, but some are usually encountered only in developing nations, such as onchocerciasis and cysticercosis. Ocular toxocariasis is a well-known cause of unilateral ocular disease affecting mainly children and young adults, and is usually caused by T canis. Prevention of ocular toxocariasis is based on such measures as appropriate health care for dogs and cats, including regular anthelmintic treatments, preventing contamination of the environment with feces, and promoting responsible pet ownership [1,49-51]. Onchocerciasis is caused by infection with the filarial parasite O volvulus, and occurs in endemic areas along rivers and streams. In hyperendemic areas almost every person is infected and about half of the population is eventually blinded by onchocerciasis. Because of this, elimination of host-vector contact is very important. DUSN is caused by a motile nematode and is found in the Southeastern and Midwestern United States and in many parts of the world. In Brazil, DUSN is becoming an important cause of posterior uveitis in children and young healthy adults. The destruction of the worm during the early stages of the disease can prevent progression of the visual loss. It is important to remain aware of this entity, not only in areas where it has been described, but also in regions not yet identified as being endemic [52]. Cysticercosis is caused by the encystment of the larvae of the tapeworm T solium, and usually results from ingesting eggs from food, water, or other material contaminated with human feces. Surgical removal of the cyst is usually indicated when possible.

Parasitic Disease of the Bovine Nervous System

Parasitic disease of the nervous system of cattle is mainly caused by migrating nematodes, expanding cestode cysts, or by rickettsiae and protozoa in the central nervous system. Common parasitic causes of neurologic diseases in cattle in the United States are Hypoderma larvae, toxins produced by Dermacentor ticks, and metabolic changes associated with intestinal coccidiosis.