A 6 year Geohelminth infection profile of children at high altitude in Western Nepal

A comparative study of traditional and molecular diagnostic methods for detection of gastrointestinal parasites in Nepalese migrants to the UK

BACKGROUND

We evaluated the results of examining a single faecal sample for gastrointestinal parasites (GIP) using a combination of traditional methods with multiplex qPCR for helminths and protozoa, compared to a reference standard of examining three faecal samples from each person using traditional diagnostic methods alone.

METHODS

Three faecal samples were collected at weekly intervals from 596 healthy Nepalese men. Each sample underwent formalin-ethyl acetate (FEA) concentration and light microscopy, and charcoal culture. The combined results of these investigations for all three stool samples were designated the reference standard. The first sample was also analysed using a multiplex TaqMan™ qPCR assay, screening for five helminths and three protozoa. We compared sensitivity and specificity of analysing the first faecal sample with qPCR alone, or a hybrid approach combining qPCR with traditional methods, to the reference standard. Additionally, a serum sample was taken from each participant for Strongyloides stercoralis IgG ELISA.

RESULTS

The reference standard identified 139 GIP infections in 133 (22.3%) participants. Use of qPCR alone in one stool identified 176 infections in 147 (24.8%) participants, rising to 187 infections in 156 (26.3%) when combined with FEA microscopy and charcoal culture. The sensitivity of this latter hybrid approach was 100% for Strongyloides spp., 90.9% for Trichuris trichiura, 86.8% for hookworm species and 75% for Giardia duodenalis compared to the reference standard. The hybrid approach increased the detected prevalence of G. duodenalis by 4.5% (27 cases) overall, T. trichiura by 2.9% (17 cases), Strongyloides spp. by 1% (6 cases), and hookworm by 0.5% (3 cases), compared to the reference standard.

CONCLUSION

Examination of a single faecal sample using qPCR alone showed superior or equivalent sensitivity to traditional methods for most GIP infections when both were compared to the reference standard. Combining molecular and traditional methods to analyse a single stool improved the detection rate for most studied parasites. This approach has value in settings where repeated sampling and/or faecal culture for helminths is impractical, but molecular diagnostics are available.

Gastrointestinal parasite infections in Nepalese Gurkha recruits arriving in the United Kingdom from 2012-2020

BACKGROUND

Gastrointestinal parasite (GIP) infections are a major cause of global morbidity, infecting hundreds of millions of people each year and potentially leading to lifelong infection and serious complications. Few data exist on screening for GIP infections in migrants entering the UK or on the current performance of different traditional diagnostic approaches. This study aimed to describe the prevalence of GIP infections in Nepalese Gurkha recruits screened on arrival in the UK.

METHODOLOGY/PRINCIPAL FINDINGS

We present a retrospective analysis of data from screening male adults (18-21 years) who arrived in the UK from Nepal between 2012 and 2020. Three separate faecal samples were obtained from participants at weekly intervals and processed for formalin-ethyl acetate (FEA) concentration/light microscopy and charcoal culture. Serum samples were analysed for IgG antibodies to Strongyloides stercoralis by ELISA. Results were available from 2,263 participants, of whom 463 (20.5%, 95% CI 18.8%-22.2%) had a positive diagnostic test for at least one GIP infection. A total of 525 potential infections were identified. Giardia duodenalis was most common (231/2263, 10.2%), followed by S. stercoralis (102/2263, 4.5%), and hookworm species (86/2263, 3.8%). Analysis (microscopy and culture) of the initial stool sample diagnosed only 244/427 (57.1%) faecally identified pathogens, including 41/86 (47.7%) hookworm infections. The proportion of participants infected with any GIP showed a downward trend over the study period. Log-binomial regression showed risk of infection decreasing by 6.1% year-on-year (95% CI 3.2% - 9.0%). This was driven predominantly by a fall in hookworm, S. stercoralis and Trichuris trichiura prevalence.

CONCLUSIONS/SIGNIFICANCE

The level of potentially pathogenic GIP infection in young Nepalese men migrating to the UK is high (20.5%) and requires a combined diagnostic approach including serology and analysis of multiple stool samples incorporating specialised parasitological methods. Advances in molecular approaches may optimise and simplify the intensive screening strategy required.

Geographic information system and foldscope technology in detecting intestinal parasitic infections among school children of South India

BACKGROUND

Effective and efficient use of technological advances will ease public health interventions and also help in reaching a larger population. Geographic Information System (GIS) and Foldscope are two such technologies, which have promising utilities in public health. Identifying intestinal parasitic infections early through feasible technologies will help in their effective management. With this objective, this study was conducted to assess the prevalence of intestinal parasitic infections among school children in southern districts of Karnataka, India.

METHODS

This cross-sectional study was conducted among randomly selected 10 urban, 10 rural, and 5 tribal schools of southern districts of Karnataka. A total of 1052 children studying in these schools were selected. Stool samples were collected and examined under Foldscope for parasitic infestation. The schools where children with worm infestations present were plotted in the GIS map.

FINDINGS

Among 1052 children included in this study, 139 (13.2%) were found to have an intestinal parasitic infestation. Among these children, 24.6% were in the age group of 5-9 years, 12.2% were males, and 14.4% were females. Urban students had higher odds (2.765) of parasitic infections compared to rural students. Mean age, height, and weight were significantly lesser among subjects with a worm infestation.

INTERPRETATION

Utility of Foldscope and GIS was found to be feasible and effective in the detection and mapping of parasitic infestations. The prevalence of parasitic infestation was found to be high among urban school children. Age, weight, height, and urban residence were found to be the major predictors of outcome.

Clinico-epidemiological spectrum of strongyloidiasis in India: Review of 166 cases

Strongyloidiasis is frequently asymptomatic but can cause disseminated disease and variable presentations. Diagnosis is often delayed or misdirected either due to poor degree of clinical suspicion or clinical imitation of other gastrointestinal conditions. This infection is not infrequent and several cases from all over India have been reported barring few states from central India. We reviewed 166 cases published in English literature from India; from 2001 till 2018 including 2 recent cases from our institute. The mean age of presentation was 35 years with male female ratio of 2.8:1. The duration of disease at the time of presentation varied from 15 days to 10 years. Most important predisposing factor identified in the study was HIV (13.3%) and steroid therapy (6.6%). Most common modality of diagnosis was by stool microscopy (69.3%). Radiological investigations were ordered in 33.7% patients before stool microscopy. Ivermectin was the most common treatment regimen with cure rate of 97.6%. Better awareness and early clinical suspicion of the disease with stool microscopy and adequate therapy are necessary to improve the outcome. Strongyloidiasis is rather widely prevalent infection with variable symptomatology and calls for a close coordination from family physicians and microbiologists.

Trends in prevalence of soil-transmitted helminth and major intestinal protozoan infections among school-aged children in Nepal

OBJECTIVES

To assess the trends in prevalence of soil-transmitted helminths (STHs), Entamoeba histolytica and Giardia lamblia among school-aged children in Nepal between 1990 and 2015.

METHODS

Systematic literature search in PubMed, MEDLINE, EMBASE, Google Scholar and local peer-reviewed journals for papers published between 1990 and December 2015. We conducted metaregression and meta-analyses to pool studies where applicable.

RESULTS

Thirty-nine studies that examined a total of 14 729 stool specimens were included in the meta-analyses. The metaregression of prevalence of hookworms, roundworm, and whipworm showed a significantly decreasing trend over time. In or after 2004, the pooled prevalence of hookworm infections was 1.53% (95% CI, 0.73-2.59), of roundworm 4.31% (95% CI, 2.52-6.53) and of whipworm 2.89% (95% CI, 1.33-4.97) vs. 16.54% (95% CI, 7.64-27.97) for hookworm, 25.20% (95% CI, 13.59-38.97) for roundworm and 11.54% (95% CI 4.25-21.76) for whipworm in 1993-2003. E. histolytica and G. lamblia had stable prevalence since early 1990s, with a pooled prevalences of 4.12% (95% CI, 2.73-5.77) and 9.40% (95% CI, 7.15-11.92), respectively. The prevalence of G. lamblia was significantly higher in urban areas.

CONCLUSIONS

We observed a sharp decrease in prevalence of STHs among school-aged children in Nepal in the past decade with prevalences dropping below 5% for STHs with no variation in prevalence in rural and urban areas. However, the prevalence of E. histolytica and G. lamblia remained stable over time. These results suggest that school-based deworming programmes rolled out during the study period had an observable impact on prevalence of STHs.

Prevalence and risk factors of soil-transmitted helminth infection in Nepal

BACKGROUND

The purpose of this study is to evaluate the prevalence and intensity and examine the risk factors of soil transmitted helminth (STH; i.e., roundworm [Ascaris lumbricoides], hookworms [Ancylostoma duodenale and Necator americanus], and whipworm [Trichuris trichiura]) infections in Nepal.

METHODS

Five hundred and ninety-four adults (256 men and 338 women) were selected via convenience sampling from five communities in Nepal. The Kato-Katz method was used to assess the prevalence and intensity of STH infection in this population.

RESULTS

Prevalence of STH infection ranged from 3.3% in Birendranagar in Chitwan, 3.5% in Kuleshor in Kathmandu, 11.7% in Kanyam in Ilam, 17.0% in Dhikurpokhari in Kaski and 51.4% in Khokana in Lalitpur District [corrected]. Multivariable regression analysis revealed that not using soap for hand-washing was significantly associated with the prevalence and infection intensity of roundworm, hookworms and whipworm. Similarly, not wearing sandals or shoes outside was significantly associated with the prevalence and infection intensity of roundworm and hookworms, but not with infection intensity of whipworm. Literacy, being underweight or overweight, anemia and occupation were not associated with prevalence and intensity of roundworm and hookworms infection, but there was an association between occupation and the prevalence of whipworm infection.

CONCLUSION

STH infection was associated with individual hygiene behavior, but not with nutritional status or socio-demographic characteristics. Health policy focusing on changing individual hygiene behaviors might be useful in addressing STH infection in Nepal.

Intestinal parasitic infestation in combatants and their families: a hospital-based study in Mid-Western Regional Police Hospital, Nepal

OBJECTIVE

To find out the scenario of intestinal parasitic infestation in combatants and their families in the setting of Mid-Western Regional Police Hospital (MWRPH), Nepal.

STUDY DESIGN

Cross-sectional study.

METHODS

All 2005 patients presented with the complaint of abdominal pain, diarrhoea, frequent defecation, blood in stool, or black stool from August 2007 to February 2011 were offered a stool examination. About 10g of fresh stool was collected in a clean, dry bottle. Two slides from each specimen were examined applying light microscope in 10 and 40 uvf at Banke, Nepalgunj hospital laboratory.

RESULT

Among 2005 patients, 928 (46.28%) were infested with either helminths and/or protozoa. 96% were single infestation. The most common infestation was Ascaris lumbricoides (48.06%) and the second was hook worm (18.97%). Most common protozoal infestations were Entamoeba histolytica (12.92%) and Giardia lamblia (9.49%). Helminthic infestations peaked in cool months and protozoal infestations were rather steady throughout the year.

CONCLUSION

Very high parasitic infestation in least developed mid- western Nepal may need urgent public health intervention.