Tropical Parasitology最新文献

Enterobius vermicularis, also known as pinworm or threadworm, is a large intestinal nematode which has a high prevalence among children and peripubertal age in our country. Transmission usually occurs by autoinfection like finger contamination of the embryonated eggs deposited by the gravid female worm on the perianal and perineal region. Globally, only a few reports are there regarding the isolation of the parasite from extra-intestinal sites. These are two rare case reports of ocular enterobiasis. The first case was a middle-aged female and the second one was a 14-year-old girl, both of whom were referred from other tertiary care hospitals to Calcutta School of Tropical Medicine and who presented with discharge of live motile worms from their eyes (conjunctiva). In both the cases, identification was done by saline wet mount and direct microscopy of a gravid female worm. Plano-convex embryonated eggs were also observed. The oval embryonated eggs, plano-convex in shape, and the gravid female, with its cervical alae near the anterior end and straight thin pointed tail, were identified under the microscope. Although E. vermicularis is a very common large intestinal parasitic infestation of children and adolescents, it can also rarely be isolated from unusual sites, which should be taken into account for effective diagnosis and treatment.

Context: Cyclosporiasis is an emerging enteric coccidian parasitic disease worldwide, caused by the parasite Cyclospora cayetanensis. There is scanty data from India, especially among immunocompetent patients.

Aims: The aim is to evaluate the occurrence of Cyclosporiasis in immunocompetent and immunocompromised patients.

Settings and design: It is a prospective cohort study conducted from June 2006 to May 2018 at our tertiary care center.

Materials and methods: Stool samples were collected from the 900 patients with diarrhea (both immunocompetent and immunocompromised) and 170 healthy controls to look for Cyclospora by modified Kinyoun staining.

Statistical analysis: Mann-Whitney U test/Fisher exact test were used for statistical analysis.

Results: Oocysts of C. cayetanensis were detected in 10/900 patients and none of the healthy controls. The median age of patients was 38.5 years (10-65 years) and males (6/10) outnumbered the females in harboring the parasite. Eight patients were immunocompromised (five postrenal transplant cases and one-one patient each with HIV, non-Hodgkin's lymphoma, and juvenile polyarthritis), and two patients were immunocompetent. Cyclospora infection was more common in immunocompromised patients (8/300, 2.67%) than the immunocompetent patients (2/600, 0.33%); P < 0.001. Eight patients responded well to trimethoprim-sulfamethoxazole, one died, and one was lost to follow-up. Coinfection with Cryptosporidium spp. was seen in one patient.

Conclusion: Cyclospora causes diarrhea in both immunocompromised and immunocompetent persons. Its burden may be underestimated due to a lack of awareness and appropriate diagnostic methods. Special staining techniques are important for diagnosis as they may be missed by routine microscopy.

Entamoeba histolytica (E. histolytica) is an enteric microaerophilic protozoan parasite responsible for millions of cases worldwide. Majority of the infections due to E. histolytica remain asymptomatic; however, it can cause an array of symptoms ranging from devastating dysentery, colitis, and abscesses in different vital organs. The interactions between the E. histolytica and its host are a multifaceted chain of events rather than merely destruction and invasion. There are manifold decisive steps for the establishment of infections by E. histolytica which includes degradation of mucosal layer, adherence to the host epithelium, invasion into the host tissues, and dissemination to vital organs. It is widely hypothesized that, for establishment of infections, the interactions at the intestinal mucosa decides the fate of the disease. The delicate communications between the parasite, the host factors, and the associated bacterial microflora play a significant role in the pathogenesis of E. histolytica. In this review, we summarize the interactions between the E. histolytica and it's host at the genetic and immunological interphases emphasizing the crucial role of microbiota in these interactions.

Introduction: Dientamoeba fragilis (D. fragilis) diagnosis is an intestinal protozoan parasite globally found in rural and urban areas and is attracting a growing interest. Its prevalence in stool varies from 0.2% to more than 19% depending upon the population studied.

Materials and methods: This study was based on the examination of 100 stool samples of randomly referred cases in a rural area in Motobus district, Kafr El-Sheikh governorate, Egypt. Our aim was to investigate the presence of D. fragilis in stool of the examined individuals using conventional polymerase chain reaction (PCR) compared to wet mount and trichrome stain with confirmation of infection by transmission electron microscopy.

Results: D. fragilis was detected in 13/100 of the stool samples examined using wet mount smears, while trichrome stain detected 17/100. Conventional PCR diagnosed 41 cases of D. fragilis in the studied group. A very good agreement was found between wet mount and trichrome stain for diagnosing D. fragilis, while there was fair agreement between conventional PCR and both microscopy methods. Transmission electron microscope was performed on pooled positive samples that revealed the internal structures of D. fragilis trophozoite with its characteristic nucleus.

Conclusions: PCR technique was superior to microscopy for the detection of D. fragilis. Trichrome stain remains vital for microscopic diagnosis.

Introduction: Scabies has been a continuous health concern in residential institutions including boarding schools in Indonesia. The disease easily spreads in overcrowding residences. Using one of several boarding schools in Medan, Indonesia, as study site, we conducted this study to better understand the underlying factors behind scabies incidence in boarding schools. We hoped to be able to promote more effective preventive measures toward the disease.

Materials and methods: We included all of 220 students (115 males and 105 females) in a cross-sectional descriptive analytical study, whose ages were ranging from 10 to 18 years. The diagnosis of scabies was made based on interview and physical examination. Skin scraping followed by microscopic assessment was carried out upon finding scabies-related lesion. Data on risk factors were collected using a set of pretested questionnaire and direct observation. Data were analyzed using bivariate and multivariate analysis the with Chi square and logistic regression.

Results: We found a high prevalence clinical scabies, i.e., 81 (36.8%) students, yet only one came out positive with skin scraping and microscopic examination. The factors associated with the infection were found to be younger age (odds ratio [OR]: 2.95, 95% confidence interval [CI] 0.97-6.09), sharing clothes (OR: 8.22, 95% CI 2.37-28.48), sharing bed (OR: 17.53, 95% CI 5.55-56.02), and unhygienic bedroom condition (OR: 8.18, 95% CI 3.30-20.28).

Conclusions: The results imply the need for better strategies to prevent the transmission of astigmatid mites within the risky populations. We promote six recommendations for a more applicable approach toward scabies prevention in boarding schools and other institutional facilities alike.

The steady and ongoing change in climatic patterns across the globe is triggering a cascade of climate-adaptive phenomena, both genetic and behavioral in parasites, and influencing the host-pathogen-transmission triangle. Parasite and vector traits are now heavily influenced due to increasing temperature that almost dissolved geospatial boundaries and impacted the basic reproductive number of parasites. As consequence, continents unknown to some parasites are experiencing altered distribution and abundance of new and emerging parasites that are developing into a newer epidemiological model. These are posing a burden to healthcare and higher disease prevalence. This calls for multidisciplinary actions focusing on One Health to improve and innovate in areas of detection, reporting, and medical countermeasures to combat the growing threat of parasite emergence owing to climate adaptations for better public health outcomes.

Introduction: Giardiasis is one of the greatest public parasitic infections causing diarrheal and also known to be associated with high morbidity and mortality, among the children's particularly in developing countries with less cleanliness practices. Thus, studying genomic variety of Giardia intestinalis aids to improve our perspective related to the variability in the genome of the parasite.

Materials and methods: In this cross-sectional study, 1006 stool samples were collected from the rural (n = 500) and urban settings (n = 506) from the children (<15 years) with and without symptoms and were screened for the presence of G. intestinalis by polymerase chain reaction (PCR) targeting triosephosphate isomerase gene. Further, all PCR-positive amplicons were subjected to restriction fragment length polymorphism using RsaI restriction enzyme.

Results: Of the total 1006 stool samples, 500 samples from rural screened by PCR 108 (21%) were found to be positive for assemblage A, 116 (23.2%) belong to assemblage B, and 5 (1%) were mixed assemblages (A + B). Whereas in urban, of the 506 samples screened by PCR, 92 (18.1%) were found to be positive for assemblage A, 93 (18.3%) assemblage B, and 10 (1.9%) were mixed assemblages (A + B). No significant difference was found between the G. intestinalis assemblages with clinical details of symptomatic and asymptomatic in children.

Conclusions: This signifies the first study inspection in our location to shed lights and delivers some preliminary data on assemblages and subassemblages. The results suggest that anthroponotic transmission could be a foremost transmission path for giardiasis among the study population.