Prevalence of intestinal protozoan parasites among school children in Africa:a systematic review and meta-analysis

INTRODUCTION: Parasitic infections, especially intestinal protozoan parasites (IPPs) remain a significant public health issue in Africa, where many conditions favour the transmission and children are the primary victims. This systematic review and meta-analysis was carried out with the objective of assessing the prevalence of IPPs among school children in Africa. METHODS: Relevant studies published between January 2000 and December 2020 were identified by systematic online search on PubMed, Web of Science, Embase and Scopus databases without language restriction. Pooled prevalence was estimated using a random-effects model. Heterogeneity of studies were assessed using Cochrane Q test and I(2) test, while publication bias was evaluated using Egger’s test. RESULTS: Of the 1,645 articles identified through our searches, 46 cross-sectional studies matched our inclusion criteria, reported data from 29,968 school children of Africa. The pooled prevalence of intestinal protozoan parasites amongst African school children was 25.8% (95% CI: 21.2%-30.3%) with E. histolytica/ dispar (13.3%; 95% CI: 10.9%-15.9%) and Giardia spp. (12%; 95% CI: 9.8%-14.3%) were the most predominant pathogenic parasites amongst the study participants. While E. coli was the most common non-pathogenic protozoa (17.1%; 95% CI: 10.9%-23.2%). CONCLUSIONS: This study revealed a relatively high prevalence of IPPs in school children, especially in northern and western Africa. Thus, poverty reduction, improvement of sanitation and hygiene and attention to preventive control measures will be the key to reducing protozoan parasite transmission

Trichuris dysentery syndrome: Do we learn enough from case studies?

Abstract. Trichuris Dysentery Syndrome (TDS) is a severe persistent trichuriasis associated with heavy worm build-up in the colon that continues to be neglected and underestimated in endemic countries. Trichuriasis is most prevalent in children in tropical countries, and that increases the risk of TDS. We reported a series of four preschool children of both genders chronically having TDS over a period ranging from several months to years presenting with anaemia. The hemoglobin levels ranged from 4.6 to 9.1 g/dl on first admissions. Despite treatment, the cases were reported to have failure to thrive with persistent anaemia. It was concluded that TDS should be considered in endemic areas among children presenting with chronic bloody diarrhea and anaemia

Human parasitic worm detection using image processing technique

Intestinal parasites of protozoa and helminthes may cause disease or even death to animals and humans. In a current study of fecal sample examination to detect parasites, a technologist examines images manually using a lighted microscope. This method of examination is known to be inefficient when it involves a large number of samples. On top of that, it is very important to introduce a system that is capable of assisting the technologist in the examination of fecal samples. In this paper, an automatic process is proposed to detect different types of parasites from fecal samples using an image processing technique. Image processing techniques have been introduced to automatically screen the existence of parasites in human fecal specimens. This process involves methods such as noise reduction, contrast enhancement, segmentation, and morphological analysis. At the classification stage, we propose a simple classification method using logical threshold, whereby the ranges of feature values have been identified to classify the type of parasite. The proposed system has been tested with 100 parasite images of each class, which promotes accuracy

Serological IgG avidity test for ocular toxoplasmosis

Subramaniam Suresh1, Saidin Nor-Masniwati1, Muhd Nor Nor-Idahriani1, Wan-Hitam Wan-Hazabbah1, Mohamed Zeehaida2, Embong Zunaina11Department of Ophthalmology, 2Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, MalaysiaBackground: The purpose of this study was to evaluate the immunoglobulin (Ig) G avidity of serological toxoplasmosis testing in patients with ocular inflammation and to determine the clinical manifestations of ocular toxoplasmosis.Methods: A retrospective review of all patients presenting with ocular inflammation to the Hospital Universiti Sains Malaysia, Kelantan, Malaysia between 2005 and 2009 was undertaken. Visual acuity, clinical manifestations at presentation, toxoplasmosis antibody testing, and treatment records were analyzed.Results: A total of 130 patients with ocular inflammation were reviewed retrospectively. The patients had a mean age of 38.41 (standard deviation 19.24, range 6–83) years. Seventy-one patients (54.6%) were found to be seropositive, of whom five (3.8%) were both IgG and IgM positive (suggestive of recently acquired ocular toxoplasmosis) while one (0.8%) showed IgG avidity ≤40% (suggestive of recently acquired ocular toxoplasmosis) and 65 patients (50.0%) showed IgG avidity >40% (suggestive of reactivation of toxoplasmosis infection). Chorioretinal scarring as an ocular manifestation was significantly more common in patients with seropositive toxoplasmosis (P = 0.036). Eighteen patients (13.8%) were diagnosed as having recent and/or active ocular toxoplasmosis based on clinical manifestations and serological testing.Conclusion: Ocular toxoplasmosis is a clinical diagnosis, but specific toxoplasmosis antibody testing helps to support the diagnosis and to differentiate between reactivation of infection and recently acquired ocular toxoplasmosis.Keywords: ocular toxoplasmosis, chorioretinal scar, toxoplasmosis antibody, IgG avidity tes

Analysis of Entamoeba histolytica Excretory-Secretory Antigen and Identification of a New Potential Diagnostic Marker ▿

Serodiagnosis of amoebiasis remains the preferred method for diagnosis of amoebic liver abscess (ALA). However, the commercially available kits are problematic in areas of endemicity due to the persistently high background antibody titers. Human serum samples (n = 38) from patients with ALA who live in areas of endemicity were collected from Hospital Universiti Sains Malaysia during the period of 2008 to 2010. Western blots using excretory-secretory antigen (ESA) collected from axenically grown Entamoeba histolytica were probed with the above serum samples. Seven antigenic proteins of ESA with various reactivities were identified, i.e., 152 kDa, 131 kDa, 123 kDa, 110 kDa, 100 kDa, 82 kDa, and 76 kDa. However, only the 152-kDa and 110-kDa proteins showed sensitivities above 80% in the Western blot analysis. All the antigenic proteins showed undetectable cross-reactivity when probed with healthy human serum samples (n = 30) and serum samples from other infections (n = 33). From the matrix-assisted laser desorption ionization–two-stage time of flight (MALDI-TOF/TOF) analysis, the proteins were identified as heavy subunits of E. histolytica lectin and E. histolytica pyruvate phosphate dikinase, respectively. Use of the E. histolytica lectin for diagnosis of ALA has been well reported by researchers and is being used in commercialized kits. However, this is the first report on the potential use of pyruvate phosphate dikinase for diagnosis of ALA; thus, this molecule merits further evaluation on its diagnostic value using a larger panel of serum samples

Prevalence of schistosomiasis and associated risk factors among school children in Um-Asher Area, Khartoum, Sudan

Abstract Objective Schistosomiasis remains one of the most common parasitic diseases worldwide. This is a cross-sectional study aimed to determine the prevalence of schistosomiasis and its associated risk factors among primary school children in Um-Asher area. The study was conducted among 170 primary school students in Um-Asher area from November 2017 to February 2018. Urine and stool samples were collected and examined for schistosomiasis infections. Moreover, data on sociodemographic characteristics and associated risk factors were obtained using a questionnaire. Results The overall prevalence of Schistosoma haematobium was 12.9%, whereas that of Schistosoma mansoni was 2.95%. Additionally, the males had higher prevalence (60%) of S. mansoni than females (40%). However, both gender were equally infected with S. haematobium (50%). With regard to risk factors, distance of residence from water source and source of drinking water are relatively associated with the infection