The prevalence of soil transmitted helminth infections in minority indigenous populations of South-East Asia and the Western Pacific Region: A systematic review and meta-analysis

INTRODUCTION

Soil transmitted helminth (STH) infections cause one of the most prevalent diseases in man. STHs disproportionately impact socio-economically disadvantaged communities including minority indigenous populations. This systematic review aimed to quantify the prevalence of STH infection within minority indigenous populations of the South-East Asia and Western Pacific Regions.

METHODS

The systematic review was conducted in accordance with The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines following a published protocol. A random effects meta-analysis was used to estimate the pooled prevalence of STH infection, and meta-regression analysis was used to quantify associations with study characteristics. Where comparative data were available, sub-group analysis was conducted to evaluate the risk of STH infection in minority indigenous people relative to other population groups. The heterogeneity between studies was evaluated visually using Forest plots and was assessed quantitatively by the index of heterogeneity (I2) and Cochran Q-statistics.

RESULTS

From 1,366 unique studies that were identified, 81 were included in the final analysis. The pooled prevalence of infection within minority indigenous populations was 61.4% (95% CI 50.8, 71.4) for overall STH infection; 32.3% (95% CI 25.7, 39.3) for Ascaris.lumbricoides; 43.6% (95% CI 32.6, 54.8) for Trichuris.trichiura; 19.9% (95% CI 15.7, 24.5) for hookworm and 6.3% (95% CI 3.2, 10.2) for Strongyloides.stercoralis. A significant increase in T. trichiura prevalence was observed over time. The stratified analysis showed that the prevalence of infection for STH overall and for each STH species were not significantly different in minority indigenous participants compared to other populations groups.

CONCLUSION

The prevalence of STH infection is high within minority indigenous populations across countries at very different levels of socio-economic development. The increasing prevalence of T. trichiura calls for the implementation of more effective therapies and control strategies.

Risk factors associated with soil transmitted helminth (STH) infection in two indigenous communities in Malaysia

Soil-transmitted helminth (STH) could possibly cause mild to severe health effects such as diarrhea, weakness, intestinal blood loss, and impaired cognitive development and growth. In Malaysia, previous studies depicted a high prevalence rate of STH was due to poor hygiene practice and low efficacies of anthelminthic drugs. This study was conducted to investigate hand hygiene practice and WASH criteria's (Water, sanitation and hygiene) related to STH infection among two indigenous tribes in Peninsular Malaysia. A cross-sectional study was carried out to study the relationship among STH infection compared to water quality, sanitation, and hygiene conditions. A total of 190 individuals from two indigenous villages participated in the study, with ages ranging from 5 to 60 years old. In addition, Pearson's Chisquare (X²) test was utilized to test the relationship among STH with demographic socioeconomic and behavioral factors. The confidence interval (CI) of 95% is used to estimate the precision of the odds ratio (OR). Multivariate logistic regression models were also used to identify the risk factors associated with STH infections. The overall findings indicated a prevalence rate of 72% for STH, and distributed mainly among children aged < 12 years. Furthermore, multivariate analyses using logistic regression revealed chronic health problems, incorrect hand washing, and walking bare footed were associated with STH infection. Overall results indicated high prevalence of STH among the indigenous villagers, which aligns with the published literature and proves to be a problem need to be addressed as neglected disease. Interestingly, there was a significant relationship between the presences of chronic diseases and STH infection, which prompted other questions the awareness needs to be educated and the simple and low-cost intervention on the proper way of hand washing may help to reduce STH infection in these indigenous communities.

Shadow Puppets and Neglected Diseases: Evaluating a Health Promotion Performance in Rural Indonesia

'Rama and the Worm' is a shadow puppet production targeting neglected diseases in Central Java. It is an entertainment-based intervention study to promote health by reducing the impact of parasitic diseases such as soil-transmitted helminths (STH). The study uses traditional Javanese shadow puppetry (wayang kulit) as a vehicle in village communities to disseminate health messages and promote behaviour change to prevent diseases caused, primarily, by inadequate sanitation and poor hygiene. The health education messages contained in the play, although using traditional characters and themes, required the creation of a completely new narrative script, using characters and plot lines familiar to the wayang kulit repertoire, but placing them in new situations that relate specifically to health promotion objectives. The intervention was piloted in a village in Central Java, Indonesia using a pre/post design with both qualitative and quantitative analysis. A total of 96 male and female villagers, aged between 7 and 87 years, provided both baseline and follow up data. Participant knowledge and behaviours related to gastrointestinal and helminth-related disease were assessed before and after the intervention through a questionnaire administered by interview. Results revealed statistically significant improvements in both knowledge (48.6% pre-intervention score vs. 62.8% post-intervention score, p < 0.001) and behaviour (77.4% vs. 80.6%, p = 0.004) related to gastrointestinal and helminth disease. Findings of the study indicate the wayang kulit performance is an effective health education tool. The results provide proof of concept with scaling up the next step forward. The wayang kulit production provides a significant additional component for an integrated, comprehensive approach to reduction and elimination of STH infection.

Neglected tropical diseases among two indigenous subtribes in peninsular Malaysia: highlighting differences and co-infection of helminthiasis and sarcocystosis

Soil-transmitted helminth (STH) infections have been documented among these minority groups since 1938. However the prevalence of STH is still high among these communities. Most studies tend to consider the Orang Asli (indigenous) as a homogenous group. In contrary, different subtribes have their own cultural practices. To understand this variation better, we studied the prevalence and associated factors of STH and other gut parasitic infections among two common subtribes (i.e. Temuan and Temiar). Results showed that the prevalence of the overall STH infections was higher in the Temuan subtribe (53.2% of 171) compared to the Temiar subtribe (52.7% of 98). Trichuris trichiura (46.2%) was the most prevalent parasite in the Temuan subtribe, followed by Ascaris spp. (25.7%) and hookworm (4.1%). In contrast, Ascaris spp. (39.8%) was more prevalent among the Temiar subtribe, preceded by T. trichiura (35.7%) and finally hookworm (8.3%). There were also co-infections of helminthiasis and intestinal protozoa among both Temuan and Temiar subtribes with rates being three times higher among the Temiar compared to Temuan. The most common co-infection was with Entamoeba histolytica/dispar/moshkovskii (n = 24; 24.5%, 16.0-33.0), followed by Giardia spp. (n = 3; 3.1%, -0.3-6.5). In Temuan, STH infection individuals were also infected with Entamoeba histolytica/dispar/moshkovskii (n = 11; 6.4%, 5.0-13.8), Cryptosporidium spp. (n = 3, 1.8%, -0.2-3.8) and Giardia spp. (n = 2, 1.2%, -0.4-2.8). In comparison, there was no Cryptosporidium spp. detected among the Temiar. However, it was interesting to note that there was an occurrence of co-infection of intestinal helminthiasis and sarcocystosis (intestinal) in a Temiar individual. The last report of sarcocystosis (muscular) among the Orang Asli was in 1978. The present study highlighted the importance of understanding the variation of infections amongst the different Orang Asli subtribes. It is vital to note these differences and use this knowledge to customise effective control measures for the various subtribes.

Relevance of eosinophilia and hyper-IgE in immigrant children

Immigrants from undeveloped countries are a growing problem in Europe. Spain has become a frequent destination for immigrants (20% of whom are children) because of its geographic location and its historic and cultural links with Africa and Latin America. Eosinophilia is frequent in adult immigrants, travelers and expatriates coming from tropical areas. However, there are few studies that focus on the incidence and causes of tropical eosinophilia and hyper-IgE in immigrant children.We evaluated, prospectively, the prevalence and causes of eosinophilia and hyper-immunoglobulin E (IgE) in 362 immigrant children coming from Sub-Saharan Africa, Northern Africa and Latin America to Salamanca, Spain, between January 2007 and December 2011.Absolute eosinophilia and hyper-IgE were present in 22.9% and 56.8% of the analyzed children, respectively. The most frequent causes of absolute eosinophilia were filariasis (52.6%), strongyloidiasis (46.8%) and schistosomiasis (28.9%). Filariasis (41.9%), strongyloidiasis (29.6%) and schistosomiasis (22.2%) were the most frequent causes of increased levels of IgE. The area under the ROC curve showed similar values between eosinophil count and IgE levels in the diagnosis of helminthiasis (69% [95% confidence interval (CI) 63%-74%] vs 67% [95% CI 60%-72%], P = 0.24). Eosinophilia and hyper-IgE have a high value as biomarkers of helminthiasis in children coming from tropical and subtropical areas.

Anemia in Cambodia: prevalence, etiology and research needs

Anemia is a severe global public health problem with serious consequences for both the human and socio-economic health. This paper presents a situation analysis of the burden of anemia in Cambodia, including a discussion of the country-specific etiologies and future research needs. All available literature on the prevalence and etiology of anemia in Cambodia was collected using standard search protocols. Prevalence data was readily identified for pre-school aged children and women of reproductive age, but there is a dearth of information for school-aged children, men and the elderly. Despite progress in nation-wide programming over the past decade, anemia remains a significant public health problem in Cambodia, especially for women and children. Anemia is a multifaceted disease and both nutritional and non-nutritional etiologies were identified, with iron deficiency accounting for the majority of the burden of disease. The current study highlights the need for a national nutrition survey, including collection of data on the iron status and prevalence of anemia in all population groups. It is impossible to develop effective intervention programs without a clear picture of the burden and cause of disease in the country.

Helicobacter pylori, helminth infections and growth: a cross-sectional study in a high prevalence population

AIM

Helicobacter pylori (H. pylori) infection is usually acquired in childhood and may adversely affect growth, although data are inconsistent. This study investigated growth parameters in a paediatric cohort with a high prevalence of H. pylori and helminth infection.

METHODS

A cross-sectional study of African refugee children (<16 years) recruited at their initial health assessment following resettlement in Australia. Detailed demographic, infection and anthropometric data were obtained. H. pylori infection was diagnosed by monoclonal faecal antigen enzyme immunoassay testing (MFAT). Growth restriction was defined as children with any anthropometric measures below the fifth centile for age and gender.

RESULTS

H. pylori infection was detected in 149/182 (81.9%). Children with H. pylori infection were older (mean 8.5 years, standard deviation (SD) 4.2 years vs. 5.8 years, SD 4.5 years, p < 0.001). No gender differences were observed. After adjustment for age, H. pylori did not adversely affect body mass index or other anthropometric measurements. Helminth infections were common (41.8%) but not associated with reduced growth or with H. pylori infection.

CONCLUSION

H. pylori and helminth infections are prevalent in African refugee children but neither is associated with growth restriction. Longitudinal growth velocity studies are necessary to identify any long-term consequences of H. pylori on childhood growth.

Community based parasitic screening and treatment of Sudanese refugees: application and assessment of Centers for Disease Control guidelines

Centers for Disease Control guidelines for schistosomiasis and strongyloidiasis in Sudanese and Somali refugees are not widely implemented. Given limited prevalence data, we conducted a seroprevalence study of schistosomiasis, strongyloidiasis, and loiasis in Sudanese refugees across diverse ages. Sudanese refugees, ages 4-78, were recruited via community organizations. Half of the patients (86/172), were seropositive for schistosomiasis (46/171; 26.9%), strongyloidiasis (56/172; 33%), or both (16/171; 9.4%). No Loa loa infections were detected. Infection rates were similar in adults and children except that no schistosomiasis was detected in children < 4 years of age at the time of immigration to the United States. The high prevalence of schistosomiasis and strongyloidiasis in a community-based sample of Sudanese confirms the urgency for compliance with CDC refugee health guidelines. We detected no co-infection with Loa loa using the most sensitive serologic techniques, allowing use of ivermectin, the most effective treatment of strongyloidiasis.

Intestinal protozoa and intestinal helminthic infections in displacement camps in Sierra Leone

Displacement and refugee camps provide ideal grounds for the transmission of parasites and increase the risk of acute respiratory infections, diarhoea diseases, and intestinal parasitic infection. Cryptosporidium parvum, Giardia lamblia, Entomoeba histolytica, Ascaris lumbricoides, hookworm infection, Schistosoma haematobium, S. mansoni and Strongyloides stercoralis are important cosmopolitan intestinal parasites that are common among children, the immunocompromised and displaced populations. Five hundred and eighty one residents from 5 Internally Displaced Persons (IDPs) Camps voluntarily participated in the study by providing stool and urine samples for analysis. The stool specimens were used for the detection of Cryptosporidium specific and Giardia specific antigens by the DMSO modified Acid-Fast and Trichrome-PLUS stain for C. parvum and G. lamblia and E. histoyltica respectively. Stool specimens for the demonstration of helminth eggs and larvae were prepared by the modified Kato technique. One hundred and seventy eight (31%) of the 581 camp residents that submited samples were children below 10 years of age and were selected because they were screened for various forms of malnutrition. However, the data on C. parvum and G. lamblia were included in the analysis for all parasites. More children were positive for G. lamblia (29%) than for C. parvum (10%) and 5% had double infection with both parasites. The antigen positive rate decreased with age for C. parvum and G. lamblia infections. Adult samples were also examined for the C. parvum, G. lamblia, E. histolytica, A. lumbricoides, hookworms, S. haematobium, S. mansoni and S. stercoralis. The prevalence of hookworm was highest at Parade Ground Camp (50%) and hookworm had the highest pevalence rate of 18% among the 581 IDP residents followed by S. mansoni (16.7%) and A. lumbricoides (15%). The overall prevalence of E. histolytica among the study population was 9.0%. The results of this study indicate that intestinal protozoan and helminth parasites are highly prevalent among camp residents in Sierra Leone with five (5) different helminth parasites demonstrated in the stool specimens of residents in the five IDP camps.

Prevalencia de enteroparásitos en niños de la etnia Yukpa de Toromo, Estado Zulia, Venezuela

BACKGROUND

Yupkpa community in Perijá Sierra does not have drinking water or sewage elimination systems. Thus it becomes a propitious place for infection with intestinal parasites.

AIM

To determine the prevalence of intestinal parasites in children, ages 0 to 14 years, in the Yukpa ethnic population of Toromo in the Perijá Mountains, Zulia State, Venezuela.

MATERIAL AND METHODS

Ninety one fecal samples were analyzed by the following coproparasitologic methods: saline solution and lugol fresh mount, formalin-ether concentration (Ritchie), and Kinyoun stain for intestinal coccidians.

RESULTS

Overall parasite infection prevalence was 83.5%. The most frequently observed parasites were: Ascaris lumbricoides (57.1%), Trichuris trichiura (20.8%), Hymenolepis nana (14.2%), Blastocystis hominis (51.6%), Giardia lamblia (30.7%), and Entamoeba histolytica/E. dispar complex (21.9%). Coccidians were nont observed in any of the stool samples.

CONCLUSIONS

The large number of infected people is directly related to the hygienic and sanitary conditions of the population studied.

Intestinal helminth infection in an ethnic minority commune in southern Vietnam

A program to control intestinal helminth infections, based on stool surveys, mass treatment of children below 17 years, improvement of sanitation and health education was performed between 1997 and 1999 in Phan Tien, an ethnic minority community in mountainous southern Vietnam. Before intervention, 28.6% of children excreted eggs of at least one parasite, hookworm being the most common (23%), followed by Trichuris trichiura (1.9%), Hymenolepis nana (1.9%), Enterobius vermicularis (0.9%), Ascaris lumbricoides (0.5%), and multiple kinds of helminthes (0.5%). Strongyloides stercoralis was never detected. Poor sanitation and personal hygiene, and walking barefoot were considered the main risk factors for intestinal helminth infections. The success of 400 mg albendazole single dose mass treatment was initially frustrated by the poor quality of the drug formulation used, only containing half of the indicated amount of albendazole. Using another formulation quickly reduced the hookworm infection rate. Praziquantel was used to treat H. nana infections. After three years of intervention, intestinal helminth infections were reduced to 3.3% (p<0.0001). We conclude that interventions combining health education, improvement of sanitation and mass treatment effectively control intestinal helminth infections, but the quality of the drugs used is an important factor.

Prevalence of intestinal parasitic infestation in schoolchildren in the northeastern part of Kathmandu Valley, Nepal

This paper presents the status of intestinal parasitosis in public schoolchildren (1 to 10 classes) in a rural area of the Kathmandu Valley, Nepal. A total of 533 schoolchildren (269 girls and 264 boys, aged 4 to 19 years) were included in this study. A questionnaire was filled out regarding hygienic and other habits, including factors predisposing to parasitic infections. Fecal samples from the children were examined by formol-ether concentration technique. The overall prevalence of parasitosis was 66.6% (395/533) with no significant difference between boys and girls (p> 0.05). Tibeto-Burman children had a non-significant higher prevalence, compared with Indo-Aryan and Dalit children (p>0.05). Half (53.8%; 191/355) of the children had multiple parasitic infections. Altogether, nine types of parasites were recovered. The recovery rate of helminths was higher (76.9%) than protozoa (23.1%). Trichuris trichiura was the most common helminth detected, followed by hookworm, Ascaris lumbricoides and others. Entamoeba coli was the most common protozoan parasite, followed by E. histolytica, Giardia lamblia and others.

Changing patterns in intestinal parasitic infections among Southeast Asian laborers in Taiwan

In order to determine whether there are changing patterns in intestinal parasitic infections among foreign laborers in North Taiwan, one fecal specimen was obtained from each of 1,569 laborers and examined by the formalin-ethyl acetate sedimentation technique. The prevalence of intestinal parasitic infections was 8.2%. Females (11.7%) had a significantly higher prevalence than males (6.9%), although there was no significant difference between Filipinos (7.7%), Thais (8.3%) and Indonesians (12.5%). Blastocystis hominis (3.4%) had the highest prevalence among the nine species of parasites detected. The significantly higher prevalence of B. hominis in the entry examination indicates an increasing trend in incoming Southeast Asian laborers. In addition, the prevalence of soil-transmitted helminth infections has become extremely low. Female laborers had a significantly higher positive rate. Although Opisthorchis viverrini/Clonorchis sinensis remains prevalent among Thais, the positive rate was also significantly reduced. These epidemiological patterns are different from those observed in previous studies and may be attributed to the long-term and constant movement of the foreign laborers.

Prevalence of anaemia and worm infestation in tribal areas of Madhya Pradesh

The study was conducted among school going children (6-14 years) of Baiga, Abuihmadia and Bharia tribes of Madhya Pradesh to assess the prevalence of anaemia and intestinal parasitic infestation among themselves. A total of 776 school going children were included in the study of whom blood samples of all and stool samples of 409 were collected. Their haemoglobin was measured and stool samples were examined under microscope for ova and cysts. The results revealed that 30.3% of the children had severe anaemia (Hb < 7g/dl) and 50% children had intestinal parasites. The most common parasites were hookworn (16.3%) and A lumbricoides (18.5%). Though hookworm ova loads indicated mild to moderate infestation in most of the children, the continued presence of worms in marginally nourished children could contribute significantly to blood loss in the intestine with resultant anaemia.

Control of intestinal helminths in schoolchildren in Low-Napo, Ecuador: impact of a two-year chemotherapy program

A school-based control program of intestinal helminths was undertaken among schoolchildren in the Low-Napo region, north-eastern Ecuador. Forty-eight percent of children were infected with one or more helminths at the first examination. The prevalence at the baseline was Ascaris 33.2% followed by hookworm 24.1% and Trichuris 6.5%. Sex was found to be a significant factor influencing the prevalence of hookworm and Trichuris. Prevalence was compared 9 months and 18 months after treatment. After 9 months, Ascaris and Trichuris prevalence had decreased but not hookworm. All of them increased after 18 months. The findings suggest that only a course of mebendazol had a minor effect on the control of helminth infections.

Immune dysregulation in Ethiopian immigrants in Israel: relevance to helminth infections?

The infectious disease background and particularly the helminth infections that are endemic in Africa could have profound effects on the host immune system. Studies that we have performed on an Ethiopian HIV- immigrant population that has recently reached Israel, lend support to this notion. They have indeed revealed a very high prevalence of helminth and several other infections with an extreme immune dysregulation, consisting of: (i) highly elevated plasma IgE, IgG, placental isoferritin, p75 soluble TNF receptor (sTNFR) levels and very high blood eosinophilia; (ii) increased secretion from phytohaemagglutinin (PHA)-simulated peripheral blood mononuclear cells (PBMC) of the cytokines IL-2, IL-4, IL-10 and p75 sTNFR, and decreased secretion of interferon-gamma (IFN-gamma) and IL-6; (iii) increased and decreased surface expression of p75 TNFR and IL-6 receptor on lymphocytes, respectively. The causal relationship between this immune dysregulation and the infectious background is highly suggestive, and could have far-reaching implications in the resistance to other infections.

[Prevalence of intestinal parasites among Thais in Israel]

Stool samples from 93 Thais working in Israel were examined for the presence of parasites. The overall prevalence of infection by 1 or more species was 74%. Opisthorchis viverrini and hookworm were the most prevalent parasites (51.6% and 44.1%, respectively). They were also the parasites most frequently found in mixed infections; about a quarter of the workers were infected with both. Other helminths found in only a few cases were: Fasciolopsis buski (3 cases), Taenia sp. (3), Paragonimus sp. (1), Ascaris lumbricoides (1), Trichuris trichiura (1) and Trichostrongylus sp. (1).

Intestinal helminthiases in Ecuador: the relationship between prevalence, genetic, and socioeconomic factors

Prevalence of infection with the intestinal helminths, Ascaris lumbricoides, Trichuris trichiura, Ancylostoma duodenale and Strongyloides stercoralis was examined in 632 residents of communities in Esmeraldas Province of Ecuador. These communities were divided into two groups according to area of habitation which reflected different socioeconomic circumstances. Attempts were made to correlate infection status with race and ABO blood group phenotype. The racial groups included blacks, Chachi amerindians, and mixed-race mestizos. Greater prevalences of infection were seen in the area of lower socioeconomic status. No racial or blood group associations with helminth infection were seen controlling for socioeconomic status.

Intestinal parasitic infection in operation Solomon immigrants

Previous studies have documented a high infection rate of intestinal parasites in Ethiopian immigrants to Israel. As a result, current treatment recommendations are for mass treatment without prior screening tests. However, the group of 15,400 Ethiopian immigrants who arrived in Israel in May 1991 (Operation Solomon) represents a somewhat different population from those who had immigrated earlier. The 1991 immigrants had spent 9-12 months in Addis Ababa before their evacuation; the conditions there, together with the provision of medical care, may have resulted in lower infection rates for intestinal parasites. The purpose of this study was to determine the prevalence of intestinal parasites in these recent immigrants to assess whether mass treatment would still be appropriate. Random stool specimens were obtained from 80 residents of a population of 650 Ethiopian immigrants who were cared for at a Jerusalem clinic. Specimens were examined at the Ministry of Health Laboratory. Of the 80 specimens 45 had sufficient quantity of stool to perform the standard Richie concentration method. Pooling results from all 80 individuals revealed 60 (75.0%) positive specimens, 53 (66.3%) with at least one pathogenic parasite, and 21 (26.3%) with multiple pathogenic parasites. These data provide the first systematic information on intestinal parasitosis in immigrants from Operation Solomon and suggest that mass treatment in this group is appropriate.

Helminth infestations in Asian women attending an antenatal clinic in England

Asian women attending an antenatal clinic in England were studied to determine the infestation rates with intestinal helminths. An overall rate of 9% was found, rising to 18% in those women resident for less than 7 years. Indians had a carriage rate of 3%, Pakistanis 7.3% and Bangladeshis 45%. Species detected were hookworm, whipworm (Trichuris trichiura), dwarf tapeworm (Hymenolepis nana) and roundworm (Ascaris lumbricoides).