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

Insights into the epidemiology, pathogenesis, and differential diagnosis of schistosomiasis

Schistosomiasis is a neglected tropical disease that is prevalent in low- and middle-income countries. There are five human pathogenic species, of which Schistosoma haematobium, Schistosoma mansoni and Schistosoma japonicum are the most prevalent worldwide and cause the greatest burden of disease in terms of mortality and morbidity. In addition, hybrid schistosomes have been identified through molecular analysis. Human infection occurs when cercariae, the larval form of the parasite, penetrate the skin of people while bathing in contaminated waters such as lakes and rivers. Schistosomiasis can cause both urogenital and intestinal symptoms. Urogenital symptoms include haematuria, bladder fibrosis, kidney damage, and an increased risk of bladder cancer. Intestinal symptoms may include abdominal pain, sometimes accompanied by diarrhoea and blood in the stool. Schistosomiasis affects more than 250 million people and causes approximately 70 million Disability-Adjusted Life Years (DALYs), mainly in Africa, South America, and Asia. To control infection, it is essential to establish sensitive and specific diagnostic tests for epidemiological surveillance and morbidity reduction. This review provides an overview of schistosomiasis, with a focus on available diagnostic tools for Schistosoma spp. Current molecular detection methods and progress in the development of new diagnostics for schistosomiasis infection are also discussed.

MaxEnt modeling of the potential risk of schistosomiasis in the Philippines using bioclimatic factors

Schistosomiasis is a parasitic infection caused by Schistosoma japonicum. It remains a principal local health issue in the Philippines, demonstrating endemicity in 28 provinces and afflicting thousands of Filipino individuals annually. Despite this, no clear distribution maps for the disease have been comprehensively reported. Therefore, species distribution modeling (SDM) employing the MaxEnt algorithm and GIS application techniques was utilized to denote the potential risk of schistosomiasis in the country. With a high AUC score of 0.846, the SDM yielded a favorable and reliable correlative map illustrating a predicted schistosomal temporal distribution concentrated primarily on the country's eastern portion with a more pronounced wet than dry season. The precipitation of the driest quarter was determined to be the most significant contributing factor among the bioclimatic variables evaluated. This suggests a possible increase in adaptations concerning the rainfall and thermal tolerances of the parasites' vectors. Moreover, socioeconomic status between Philippine regions revealed an inverse proportion with the number of schistosomiasis cases. This study also discussed the potential role of climate change on the range shifts and the potential risk of parasite infection in the Philippines.

Prevalence and factors associated with ongoing transmission of Schistosoma haematobium after 12 rounds of Praziquantel Mass Drug Administration among school age children in Southern Tanzania

Background

World Health Organization (WHO) recommends periodic praziquantel Mass Drug Administration (MDA) to vulnerable populations, especially school-aged children, to reduce the risk of transmission. In the S. haematobium endemic Lindi region, on the southeastern coast of Tanzania, praziquantel has been distributed for more than a decade (12 rounds) in schools. However, there is a paucity of data on the current burden and factors perpetuating ongoing urogenital schistosomiasis among SAC. The study investigated the prevalence and factors associated with the ongoing transmission of S. haematobium among school-age children (SAC) after 12 rounds of praziquantel in Nachingwea, Southern Tanzania.

Material and methods

A quantitative cross-sectional study was conducted between May and June 2022 among 483 SAC in the Nachingwea district. Macrohematuria, microhaematuria, and S. haematobium eggs were assessed in the collected urine sample for each participant, using macroscopic observation, urine dipstick, and urine filtration techniques, respectively. Infection intensity was quantified for positive S. haematobium urine samples. Knowledge and attitudes towards schistosomiasis were assessed among participants through an interview-administered questionnaire, and water contact practices were registered through an observation checklist. Data were summarized using descriptive statistics, the Chi-square test, and logistic regression.

Results

The prevalence of S. haematobium infection was 10.6%, with 0.6% (3/51) prevalence of heavy infection. The factors associated with S. haematobium persistence transmission were a habit of visiting the water bodies (AOR = 1.62, 95% CI: 0.40-1.96), swimming in the visited water bodies (AOR = 4.58, 95% CI: 1.72-12.19), using water from the river source (AOR = 3.79, 95% CI: 1.51-9.51) and attending Mkumba Primary School (17.4%; AOR = 6.12, 95% CI: 1.64-22.85).

Conclusions

Findings suggest ongoing transmission of urogenital schistosomiasis in the Nachingwea District despite 12 rounds of praziquantel treatment, with a low prevalence of heavy infection (0.6%). Praziquantel distribution should be complemented with health education, especially on the cause and transmission of urogenital schistosomiasis to increase knowledge that will improve a good attitude towards schistosomiasis prevention. An adequate water supply is to be considered to reduce infections due to the visit to water sources for daily use.

Prevalence and correlates of Schistosoma haematobium infections among school going-children aged 5 to 17 years in Kawama, Ndola, Zambia

Introduction

schistosomiasis is a neglected tropical disease and remains a disease of public health concern. Despite its relative importance, paucity of information on schistosomiasis in urban settings such as Ndola remains. Here, we present findings on the prevalence and factors associated with Schistosoma haematobium (S. haematobium) infections among School-going children in the Kawama in Ndola district in Zambia, an urban area in the Copperbelt Province, Zambia.

Methods

we employed a cross-sectional study design among 354 school going-children between 5 and 17 years of age between November 2020 and February 2021. A Multivariate forward step-wise logistic regression model was used to determine the associations of risk factors. Adjusted odds ratios and 95% confidence intervals are reported.

Results

of the 354 school-going children included in the analysis, 13.3% had S. haematobium infection. Children who swam in the stream/dam were more likely to have S. haematobium infection as compared to those who did not (aOR 6.531, 95% CI: 2.90-14.69).

Conclusion

S. haematobium infection is endemic among school-going children in an urban setup of the Kawama area of Ndola City, Zambia. There is a need for targeted interventions to mitigate infections among this population.

Accuracy of Diagnostic Tests for Detecting Schistosoma mansoni and S. haematobium in Sub-Saharan Africa: A Systematic Review and Meta-Analysis

Introduction

Schistosomiasis is causing high morbidity and significant mortality in endemic areas. Kato-Katz stool examination and urine filtration techniques are the conventional methods for the detection of intestinal and urinary schistosomiasis. The most appropriate diagnostic tools for the detection of schistosomiasis especially in low-prevalence settings should be used. Therefore, this study is aimed at investigating the diagnostic accuracy of S. mansoni and S. haematobium diagnostic tools in sub-Saharan Africa.

Methods

Electronic databases such as PubMed, PubMed Central/Medline, HINARI, Scopus, EMBASE, Science Direct, Google Scholar, and Cochrane Library were reviewed. The pooled estimates and heterogeneity were determined using Midas in Stata 14.0. The diagnostic accuracy of index tests was compared using the hierarchical summary of the receiver operating characteristic (HSROC) curve in Stata 14.0.

Results

Twenty-four studies consisting of 12,370 individuals were tested to evaluate the accuracy of antigen, antibody, and molecular test methods for the detection of S. mansoni and S. haematobium. The pooled estimate of sensitivity and specificity of CCA was 88% (95% CI: 83-92) and 72 (95% CI: 62-80), respectively, when it is compared with parasitological stool examination for S. mansoni detection. On the other hand, ELISA showed a pooled estimate of sensitivity and specificity of 95% (95% CI: 93-96) and 35% (95% CI: 21-52), respectively, for the examination of S. mansoni using stool examination as a reference test. With regard to S. haematobium, the pooled estimate of sensitivity and specificity of polymerase chain reaction was 97% (95% CI: 78-100) and 94% (95% CI: 74-99), respectively. Moreover, the sensitivity and specificity of urine CCA vary between 41-80% and 55-91%, respectively, compared to urine microscopy.

Conclusion

The effort of schistosomiasis elimination requires accurate case identification especially in low-intensity infections. This study showed that CCA had the highest sensitivity and moderate specificity for the diagnosis of S. mansoni. Similarly, the sensitivity of ELISA was excellent, but its specificity was low. The diagnostic accuracy of PCR for the detection of S. haematobium was excellent compared to urine microscopic examination.

Current Status of Urinary Schistosomiasis Among Communities in Kurmuk District, Western Ethiopia: Prevalence and Intensity of Infection

Background

Schistosomiasis is a highly prevalent but neglected tropical disease, particularly in sub-Saharan Africa. In Ethiopia, urogenital schistosomiasis due to Schistosoma haematobium has been known to be endemic in several lowland areas. This study was designed to determine the current prevalence and intensity of the urogenital schistosomiasis among communities in Kurmuk District, western Ethiopia.

Methods

Urine filtration technique and urine dipstick test were used to screen for S. haematobium eggs and hematuria, respectively. The data were analyzed with SPSS version 23. Logistic regression and odds ratio were used to measure associations and strength between prevalence, intensity, and independent variables. P-values <.05 at 95% CI were considered statistically significant.

Results

The overall prevalence of S. haematobium infection as determined by urine filtration was 34.2% (138/403). In bivariate analysis, the most infected (45.4%) age groups were 5 to 12 years (odds ratio [OR] = 4.16, 95% CI: 1.36-12.67), followed by 13 to 20 years (OR = 3.23, 95% CI: 1.01-10.35) with higher significant mean egg count (MEC). The mean egg intensity ranged from 2.39 in Ogendu (CI: 1.05-3.72) to 14.1 in Dulshatalo (CI: 4.98-23.12) villages. The main predictor of infection was swimming habits (adjusted odds ratio [AOR] = 2.43 [CI: 1.19-4.94]). The prevalence of hematuria was 39.2% (158/403), the odds being 2.64 times higher among participants who resided in Dulshatalo than those who resided in Kurmuk (AOR 2.64 [95% CI: 1.43-4.87], P = .004).

Conclusion

To reduce the infection and interrupt transmission, the PC in place in the area using PZQ should be strengthened and continued, alongside with provision of sanitary facilities, safe alternative water supplies and health education. The Federal Ministry of Health of Ethiopia should also collaborate with the health authorities of the Sudan government for the control of trans-boundary transmission of the disease as the transmission foci are shared between the 2 countries.

COVID-19 and Diarylamidines: The Parasitic Connection

As emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants (Omicron) continue to outpace and negate combinatorial vaccines and monoclonal antibody therapies targeting the spike protein (S) receptor binding domain (RBD), the appetite for developing similar COVID-19 treatments has significantly diminished, with the attention of the scientific community switching to long COVID treatments. However, treatments that reduce the risk of "post-COVID-19 syndrome" and associated sequelae remain in their infancy, particularly as no established criteria for diagnosis currently exist. Thus, alternative therapies that reduce infection and prevent the broad range of symptoms associated with 'post-COVID-19 syndrome' require investigation. This review begins with an overview of the parasitic-diarylamidine connection, followed by the renin-angiotensin system (RAS) and associated angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSSR2) involved in SARS-CoV-2 infection. Subsequently, the ability of diarylamidines to inhibit S-protein binding and various membrane serine proteases associated with SARS-CoV-2 and parasitic infections are discussed. Finally, the roles of diarylamidines (primarily DIZE) in vaccine efficacy, epigenetics, and the potential amelioration of long COVID sequelae are highlighted.

Drinking water and the implications for gender equity and empowerment: A systematic review of qualitative and quantitative evidence

BACKGROUND

Safe drinking water is a fundamental human right, yet more than 785 million people do not have access to it. The burden of water management disproportionately falls on women and young girls, and they suffer the health, psychosocial, political, educational, and economic effects. While water conditions and disease outcomes have been widely studied, few studies have summarized the research on drinking water and implications for gender equity and empowerment (GEE).

METHODS

A systematic review of primary literature published between 1980 and 2019 was conducted on drinking water exposures and management and the implications for GEE. Ten databases were utilized (EMBASE, PubMed, Web of Science, Cochrane, ProQuest, Campbell, the British Library for Development Studies, SSRN, 3ie International Initiative for Impact Evaluation, and clinicaltrials.gov). Drinking water studies with an all-female cohort or disaggregated findings according to gender were included.

RESULTS

A total of 1280 studies were included. GEE outcomes were summarized in five areas: health, psychosocial stress, political power and decision-making, social-educational conditions, and economic and time-use conditions. Water quality exposures and implications for women's health dominated the literature reviewed. Women experienced higher rates of bladder cancer when exposed to arsenic, trihalomethanes, and chlorine in drinking water and higher rates of breast cancer due to arsenic, trichloroethylene, and disinfection byproducts in drinking water, compared to men. Women that were exposed to arsenic experienced higher incidence rates of anemia and adverse pregnancy outcomes compared to those that were not exposed. Water-related skin diseases were associated with increased levels of psychosocial stress and social ostracization among women. Women had fewer decision-making responsibilities, economic independence, and employment opportunities around water compared to men.

CONCLUSION

This systematic review confirms the interconnected nature of gender and WaSH outcomes. With growing attention directed towards gender equity and empowerment within WaSH, this analysis provides key insights to inform future research and policy.

Prevalence and Molecular Identification of Schistosoma haematobium among Children in Lusaka and Siavonga Districts, Zambia

Schistosomiasis remains a public health concern in Zambia. Urinary schistosomiasis caused by Schistosoma haematobium is the most widely distributed infection. The aim of the current study was to determine the prevalence and risk factors of urinary schistosomiasis and identify the strain of S. haematobium among children in the Siavonga and Lusaka districts in Zambia. Urine samples were collected from 421 primary school children and S. haematobium eggs were examined under light microscopy. A semi-structured questionnaire was used to obtain information on the socio-demographic characteristics and the potential risk factors for urinary schistosomiasis. DNA of the parasite eggs was extracted from urine samples and the internal transcribed spacer gene was amplified, sequenced and phylogenetically analysed. The overall prevalence of S. haematobium was 9.7% (41/421) (95% CI: 7.16–13.08), male participants made up 6.2% (26/232) (95% CI: 4.15–9.03), having a higher burden of disease than female participants who made up 3.5% (15/421) (95% CI: 2.01–5.94). The age group of 11–15 years had the highest overall prevalence of 8.3% (35/421) (5.94–11.48). Participants that did not go fishing were 0.008 times less likely to be positive for schistosomiasis while participants whose urine was blood-tinged or cloudy on physical examination and those that lived close to water bodies were 9.98 and 11.66 times more likely to test positive for schistosomiasis, respectively. A phylogenetic tree analysis indicated that S. haematobium isolates were closely related to pure S. haematobium from Zimbabwe and hybrids of S. haematobium × S. bovis from Benin, Senegal and Malawi. The current study shows that urinary schistosomiasis is endemic in the study areas and is associated with water contact, and S. haematobium isolated is closely related to hybrids of S. bovis × S. haematobium strain, indicating the zoonotic potential of this parasite.

Schistosoma mansoni Epidemiology Among Snails, Rodents and Children: A One Health Approach

Background

Schistosoma is one of the prevalent parasitic infection in humans and animals. Schistosomiasis in children is particularly serious and results in liver and spleen enlargement, anemia, stunting, reduced ability to learn and death. The aim of this study was to measure the prevalence and distribution of schistosomiasis in children, rodents and snail populations in Aleffa and Takusa districts, north-west Ethiopia.

Methods

Disease status and exposure were simultaneously measured from December 2020 to December 2021. School children's stool specimens were collected for schistosomiasis examination by Kato Katz and formal-ether techniques. Live rodents and snails were trapped and collected in search of adult schistosoma, eggs, and cercariae, respectively. Multiple logistic regression analytic technique by using SPSS version 20 was conducted.

Results

Of 460 stool specimens examined, 116 (25.22) were found positive for S. mansoni infection. In the present finding, the possible determinants for the occurrence of intestinal schistosomiasis in school children were female sex (AOR = 1.09, 95% CI: 1.37–2.96); working with bare foot (AOR = 1.21, 95% CI: 1.08–1.52); skin cut/abrasion history (AOR = 3.6, 95% CI: 1.08–7.43) and swimming habit (AOR = 1.58, 95% CI: 1.33–1.99). The overall (n = 108) rodent prevalence of S. mansoniwas 23 (21.3%). Only 6 snails were shedding the infective stage of schistosoma cercariae.

Conclusion

The study revealed that there is a moderate prevalence of schistosomiasis in different hosts. Thus, multi-host intervention is crucial to achieving the goal of interrupting transmission of schistosomiasis in the study area. Further research to better understand and exploit the broader environmental, ecological context and encompassing dynamic interactions between all hosts over time will be crucial for building predictive models beyond the known fact of having or not having reservoirs/hybridization of schistosoma in our study area.

Performance of loop-mediated isothermal amplification (LAMP) for detection of Schistosoma mansoni infection compared with Kato–Katz and real-time PCR

The performance of loop-mediated isothermal amplification (LAMP) for detection of Schistosoma mansoni DNA from stool and urine samples in comparison with Kato–Katz and real-time polymerase chain reaction (PCR) was studied. After obtaining informed consent, 50 children participated in the present study and agreed to submit stool and urine samples. Stool samples were examined by Kato–Katz. Both real-time PCR and LAMP techniques were applied on stool and urine samples. The overall prevalence of S. mansoni was 46% in stool and urine samples as detected by the employed techniques, and 90% of cases had light infection intensity. The highest percentage of infection was diagnosed by real-time PCR (44%), followed by Kato–Katz (42%) and LAMP in the stool (36%), while the lowest percentages of infection were diagnosed by real-time PCR and LAMP in urine samples (24% and 14%, respectively). Kato–Katz, real-time PCR and LAMP showed 100% specificity where the sensitivity was 91.3%, 95.7% and 78.3%, respectively, in stool samples. Real-time PCR and LAMP showed lower sensitivity in urine samples. The LAMP assay is a promising technique for S. mansoni diagnosis in endemic countries of moderate and high-intensity infection. Yet, it needs further optimization, particularly in urine samples.

Persistence of Schistosoma haematobium transmission among school children and its implication for the control of urogenital schistosomiasis in Lindi, Tanzania

Background

Despite twelve rounds of school-based preventive chemotherapy for schistosomiasis in endemic areas of Tanzania such as Mtama district, Lindi: the burden of Schistosoma haematobium infection has remained highly conceivable due to re-infections. The factors associated with continuity of S.haematobium transmission in Mtama district, Lindi have not been fully established. This study investigated the burden and factors contributing to the ongoing transmission of S.haematobium infection in the endemic district of Mtama, Lindi.

Methods

A quantitative cross-sectional survey was carried out among 649 school-age children in the Mtama district to determine the burden and factors associated with continuity of S.haematobium infection transmission. A single urine specimen was obtained from each pupil and tested for macro- and microhaematuria, presence of S.haematobium ova, as well intensity of infection; this was complemented with a survey of Bulinus spp snail intermediate hosts and their infectivity. A structured questionnaire was employed to gather information on individual and environmental risk factors for S.haematobium transmission. Summary statistics were computed for individual variables; while a univariate and multivariate logistic regression analysis was performed to assess the association between risk factors with S.haematobium infection.

Results

Prevalence of S.haematobium infection by macro- and microhaematuria was 13.1% and 46.2% respectively. The prevalence of S.haematobium ova was 52.7%; intensity of infection was light in 53.1%, and heavy in 46.9%. Snail intermediate hosts were Bulinus globosus and B.nasutus, whose infectivity was 2.2% and 1.3%, respectively. Among the assessed risk factors, long residency (10–13 years) in the area was a significant risk factor for the continuity of S.haematobium transmission (AOR: 21.79, 95% CI: 1.37–346.4).

Conclusions

The observed 52.7% prevalence of S.haematobium infection represents unacceptably high prevalence after 12 rounds of preventive chemotherapy. Therefore, an urgent need for the implementation of integrated multiple control interventions in the Mtama district; is considered to be imperative.

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 I² 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.

Pathogenic intestinal protozoan parasites (IPPs) remain a major public health concern. Studies have documented that, the prevalence rates of protozoan infections are quite high in developing regions, particularly Africa and children are the primary victims. Despite numerous studies have been conducted on IPPs in school children in African countries, data on the burden of these infections in African school children have not yet been synthesised. This systematic review and meta-analysis was conducted to provide continent-wide prevalence of IPPs amongst African school children. Our study found that about 25.8% of the children had one or more species of intestinal protozoan parasites in their faecal specimens. E. histolytica/ dispar and Giardia spp. were the most predominant parasites amongst the study participants. The relatively high prevalence estimate of IPPs amongst African children and the considerable variation in the disease prevalence over the years, between and within countries and regions clearly indicates the needs to improve sanitation and hygiene, paying more attention to preventive control measures as well as poverty reduction which are the key to reducing protozoan parasite transmission.

Prevalence of urinary schistosomiasis in women: a systematic review and meta-analysis of recently published literature (2016-2020)

BACKGROUND

Urinary schistosomiasis is a serious threat in endemic territories of Africa and the Middle East. The status of female urinary schistosomiasis (FUS) in published literature between 2016 and 2020 was investigated.

METHODS

A systematic search in PubMed, Scopus, Google Scholar, and Web of Science, based on the 'Preferred Reporting Items for Systematic Reviews and Meta-analyses' checklist, and a meta-analysis using random-effects model to calculate the weighted estimates and 95% confidence intervals (95% CIs) were done.

RESULTS

Totally, 113 datasets reported data on 40,531 women from 21 African countries, showing a pooled prevalence of 17.5% (95% CI: 14.8-20.5%). Most studies (73) were performed in Nigeria, while highest prevalence was detected in Mozambique 58% (95% CI: 56.9-59.1%) (one study). By sample type and symptoms, vaginal lavage [25.0% (95% CI: 11.4-46.1%)] and hematuria 19.4% (95% CI: 12.2-29.4%) showed higher FUS frequency. Studies using direct microscopy diagnosed a 17.1% (95% CI: 14.5-20.1%) prevalence rate, higher than PCR-based studies 15.3% (95% CI: 6.1-33.2%). Except for sample type, all other variables had significant association with the overall prevalence of FUS.

CONCLUSIONS

More studies are needed to evaluate the true epidemiology of FUS throughout endemic regions.

Unprotected water sources and low latrine coverage are contributing factors to persistent hotspots for schistosomiasis in western Kenya

BACKGROUND

Evidence indicates that whereas repeated rounds of mass drug administration (MDA) programs have reduced schistosomiasis prevalence to appreciable levels in some communities referred to here as responding villages (R). However, prevalence has remained high or less than anticipated in other areas referred to here as persistent hotspot villages (PHS). Using a cross-sectional quantitative approach, this study investigated the factors associated with sustained high Schistosoma mansoni prevalence in some villages despite repeated high annual treatment coverage in western Kenya.

METHOD

Water contact sites selected based on observation of points where people consistently go to collect water, wash clothes, bathe, swim or play (young children), wash cars and harvest sand were mapped using hand-held smart phones on the Commcare platform. Quantitative cross-sectional surveys on behavioral characteristics were conducted using interviewer-based semi-structured questionnaires administered to assess water usage/contact patterns and open defecation. Questionnaires were administered to 15 households per village, 50 pupils per school and 1 head teacher per school. One stool and urine sample was collected from 50 school children aged 9-12 year old and 50 adults from both responding (R) and persistent hotspot (PHS) villages. Stool was analyzed by the Kato-Katz method for eggs of S. mansoni and soil-transmitted helminths. Urine samples were tested using the point-of-care circulating cathodic antigen (POC-CCA) test for detection of S. mansoni antigen.

RESULTS

There was higher latrine coverage in R (n = 6) relative to PHS villages (n = 6) with only 33% of schools in the PHS villages meeting the WHO threshold for boy: latrine coverage ratio versus 83.3% in R, while no villages met the girl: latrine ratio requirement. A higher proportion of individuals accessed unprotected water sources for both bathing and drinking (68.5% for children and 89% for adults) in PHS relative to R villages. In addition, frequency of accessing water sources was higher in PHS villages, with swimming being the most frequent activity. As expected based upon selection criteria, both prevalence and intensity of S. mansoni were higher in the PHS relative to R villages (prevalence: 43.7% vs 20.2%; P < 0.001; intensity: 73.8 ± 200.6 vs 22.2 ± 96.0, P < 0.0001), respectively.

CONCLUSION

Unprotected water sources and low latrine coverage are contributing factors to PHS for schistosomiasis in western Kenya. Efforts to increase provision of potable water and improvement in latrine infrastructure is recommended to augment control efforts in the PHS areas.

Prevalence and risk factors of schistosomiasis among primary school children in four selected regions of The Gambia

BACKGROUND

The Gambia initiated a control programme for schistosomiasis in 2015. In light of this, recent and comprehensive data on schistosomiasis is required to effectively guide the control programme. This study aimed to evaluate the prevalence and associated risk factors of schistosomiasis among primary school children in The Gambia.

METHODS

We utilised data from a previous study conducted in 2015 in 4 regions of The Gambia: North Bank Region (NBR), Lower River Region (LRR), Central River Region (CRR) and Upper River Region (URR). In the parent study, ten schools were selected randomly from each region. Urine and stool samples collected from 25 boys and 25 girls (7-14 years) in each school were examined for urinary schistosomiasis (Schistosoma haematobium infection) and intestinal schistosomiasis (Schistosoma mansoni infection) using urine filtration, dipstick and Kato-Katz methods.

PRINCIPAL FINDINGS

Urinary schistosomiasis had an overall prevalence of 10.2% while intestinal schistosomiasis had a prevalence of 0.3% among the sampled school children. Prevalence of urinary schistosomiasis was significantly different among regions (χ 2 = 279.958, df = 3, p < 0.001), with CRR (27.6%) being the most endemic region, followed by URR (12.0%), then LRR (0.6%), and NBR (0.0%). Prevalence of intestinal schistosomiasis was also significantly variable among regions, with 4 of the 5 positive cases detected in CRR and 1 case in URR. Every school sampled in CRR had at least one student infected with S. haematobium, 50% of schools in URR had S. haematobium infection, and just one school in LRR had S. haematobium infection. While S. haematobium infection was significantly higher in boys (χ 2 = 4.440, df = 1, p = 0.035), no significant difference in infection rate was observed among age groups (χ 2 = 0.882, df = 2, p = 0.643). Two of the 5 students infected with S. mansoni were boys and 3 were girls. Four of these 5 students were in the 10-12 years age group and 1 was in the 7-9 years age group. Macrohaematuria and microhaematuria were found to be statistically associated with presence of S. haematobium eggs in urine. Being a male was a risk factor of S. haematobium infection. Bathing, playing and swimming in water bodies were found to pose less risk for S. haematobium infection, indicating that the true water contact behaviour of children was possibly underrepresented.

CONCLUSION

The findings of this study provide invaluable information on the prevalence of schistosomiasis in The Gambia. This was useful for the schistosomiasis control efforts of the country, as it guided mass drug administration campaigns in eligible districts in the study area. More studies on S. mansoni and its intermediate snail hosts are required to establish its true status in The Gambia. As children sometimes tend to provide responses that potentially please the research or their teacher, data collection frameworks and approaches that ensure true responses in studies involving children should be devised and used.

Prevalence, Intensity, and Associated Factors of Schistosoma mansoni among School Children in Northwest Ethiopia

Background

Schistosomiasis is one of the Neglected Tropical Diseases in Ethiopia, and its burden may show variations from time to time across different regions. Thus, this study was aimed at determining the prevalence, intensity, and associated risk factors of Schistosoma mansoni (S. mansoni) among schoolchildren in Northwest Ethiopia.

Methods

A school-based cross-sectional study was conducted. A multistage sampling technique was used to select the study participants. Stool specimens were collected and examined using two-slide Kato-Katz method. Data were analyzed using SPSS version 20 software. Multivariate logistic regression analysis was used to identify risk factors. p values less than 0.05 were taken as statistically significant.

Result

A total of 786 schoolchildren were participated in this study. The prevalence of S. mansoni was 33.5%. The mean egg count of the parasite among the infected study participants was 523.665 eggs per gram (epg) of stool. Thirty-seven, 42, and 21 percent of the study participant's infection were due to light, moderate, and heavy infection intensities, respectively. Age of 8-11 years old (AOR = 1,687, 95%CI = 1.163, 2.892), 5^th-8^th grade level (AOR = 2.280, 95%CI = 1.348, 3.856), residing in Chuahit District (AOR = 95.559, 95%CI = 12.945, 705.419), and using untreated water for domestic supply (AOR = 1.724, 95%CI = 1.457, 2.148) were found to be risk factors for S. mansoni infection.

Conclusion

High prevalence of S. mansoni and relatively higher proportion of moderate intensity of infection in this study imply that schistosomiasis is still one of the major public health problems in Northwest Ethiopia. It is also highlighted that study sites, provision of water supply, age, and grade level of the schoolchildren were identified as a risk factors for the disease.

Schistosomiasis Mansoni Manifesting as Multiple Colonic Polyps

Schistosomiasis (bilharziasis) is a common parasitic disease in subtropical and tropical parts of Africa, some parts of the Middle East, South America, Asia, and some parts of the Caribbean. It is a major public health problem and associated with significant morbidity and mortality in endemic areas. We describe a 28-year-old male patient presenting with bleeding per rectum associated with mucus secretion, abdominal pain, anorexia, and weight loss. Blood investigation showed pancytopenia with macrocytic hypochromic anemia. Meanwhile, his colonoscopy showed two large polyps 10 cm and 50 cm away from the anal verge, each measuring 3 cm in size. Microscopic examination of multiple colonic biopsies confirmed Schistosoma mansoni. The patient was treated with praziquantel, which improved his condition. Colonic schistosomiasis is an important differential diagnosis in patients with a history of travel to endemic areas. Early diagnosis and medical management can avoid unnecessary invasive intervention in such cases.

A study on positive school children as indicators of schistosomiasis status in their families

This study aimed to evaluate schistosomiasis positive school children as indicators of infection in their families. Four hundred and sixteen stool samples of children from two primary schools were examined microscopically for Schistosoma mansoni (S. mansoni) after Kato-Katz. Equal numbers from families of schistosomiasis positive and negative school children were examined by Kato-Katz. Circulating cathodic antigen (CCA) cassette test was performed on 100 Kato-Katz negative children to detect missed S. mansoni cases if any. S. mansoni infection rates among the primary school children were 15.3% and 1.6% in high and low prevalence schools respectively. Sixty five percent of school children had light intensity infection. Family members were either negative or exhibited a prevalence rate as low as 5-6% whether related to positive or negative children. A higher infection rate of S. mansoni was detected by the CCA test compared to the Kato-Katz. Conclusively, children can be good indicators of their particular families in areas of limited resources and low endemicity. Efforts are required to permit large scale use of CCA cassette test.

Prevalence, intensity and associated risk factors of soil-transmitted helminth and schistosome infections in Kenya: Impact assessment after five rounds of mass drug administration in Kenya

Background

In Kenya, over five million school age children (SAC) are estimated to be at risk of parasitic worms causing soil-transmitted helminthiasis (STH) and schistosomiasis. As such, the Government of Kenya launched a National School Based Deworming (NSBD) program in 2012 targeting the at-risk SAC living in endemic regions, with the aim of reducing infections prevalence to a level where they no longer constitute a public health problem. The impact of the program has been consistently monitored from 2012 to 2017 through a robust and extensive monitoring and evaluation (M&E) program. The aim of the current study was to evaluate the parasitological outcomes and additionally investigate water, sanitation and hygiene (WASH) related factors associated with infection prevalence after five rounds of mass drug administration (MDA), to inform the program’s next steps.

Materials and methods

We utilized a cross-sectional design in a representative, stratified, two-stage sample of school children across six regions in Kenya. A sample size of 100 schools with approximately 108 children per school was purposively selected based on the Year 5 STH infection endemicity prior to the survey. Stool samples were examined for the presence of STH and Schistosoma mansoni eggs using double-slide Kato-Katz technique, urine samples were processed using urine filtration technique for the presence of S. haematobium eggs. Survey questionnaires were administered to all the participating children to collect information on their demographic and individual, household and school level WASH characteristics.

Principal findings

Overall, STH prevalence was 12.9% (95%CI: 10.4–16.1) with species prevalence of 9.7% (95%CI: 7.5–12.6) for Ascaris lumbricoides, 3.6% (95%CI: 2.2–5.8) for Trichuris trichiura and 1.0% (95%CI: 0.6–1.5) for hookworm. S. mansoni prevalence was 2.2% (95%CI: 1.2–4.3) and S. haematobium prevalence was 0.3% (95%CI: 0.1–1.0). All the infections showed significant prevalence reductions when compared with the baseline prevalence, except S. mansoni. From multivariable analysis, increased odds of any STH infections were associated with not wearing shoes, adjusted odds ratio (aOR) = 1.36 (95%CI: 1.09–1.69); p = 0.007; high number of household members, aOR = 1.21 (95%CI: 1.04–1.41); p = 0.015; and school absenteeism of more than two days, aOR = 1.33 (95%CI: 1.01–1.80); p = 0.045. Further, children below five years had up to four times higher odds of getting STH infections, aOR = 4.68 (95%CI: 1.49–14.73); p = 0.008. However, no significant factors were identified for schistosomiasis, probably due to low prevalence levels affecting performance of statistical analysis.

Conclusions

After five rounds of MDA, the program shows low prevalence of STH and schistosomiasis, however, not to a level where the infections are not a public health problem. With considerable inter-county infection prevalence heterogeneity, the program should adopt future MDA frequencies based on the county’s infection prevalence status. Further, the program should encourage interventions aimed at improving coverage among preschool age children and improving WASH practices as long-term infection control strategies.

This paper presents the findings of an evaluation survey conducted in Year 6 of the Kenya National School-Based Deworming (NSBD) Program, following five years (2012–2017) of prior baseline and subsequent impact monitoring. The survey was conducted in 20 counties, covering six regions in Kenya. The survey showed continued and considerable reductions in prevalence over time, with most marked decline for hookworm, followed by Ascaris lumbricoides. Overall, the mass drug administration (MDA) program has driven both STH and schistosomiasis prevalence to relatively low levels, however not to a point where they no longer constitute a public health problem in Kenya. For these neglected tropical diseases (NTDs), and STH in particular, there are relatively few published examples of programmatic impact assessments enabling refined decisions regarding helminth control strategies. Kenya’s experiences in implementing, monitoring, and evaluating a high-coverage NSBD program are a continuing and increasingly important success story for the country, which provides learnings of importance for the international community.

Comparison of the Change in the Prevalence and Intensity of Schistosoma haematobium Infection Between High and Low Prevalence Areas of White Nile State, Sudan

This study aimed to investigate whether mass drug administration (MDA) intervention has an equivalent effect on reducing the prevalence and intensity of Schistosoma haematobium infection regardless of the baseline values. A repeated cross-sectional survey was performed targeting students of 12 primary schools in Al Jabalain and El Salam districts of White Nile State, Sudan, at both 1 week before and 8 months after the MDA. Prior to the baseline survey, school-aged children in Al Jabalain had received MDA interventions twice in 4 years, while those in El Salam had not. The baseline prevalence was 9.1% in Al Jabalain and 35.2% in El Salam, which were reduced to 1.8% and 5.5% at 8 months after the MDA, respectively. The corresponding reduction rates were 80.3% and 84.4%, not significant difference between both districts. However, changes in the geometric mean intensity (GMI) of egg counts were significantly different between both districts. The baseline GMIs were 14.5 eggs per 10 ml of urine (EP10) in Al Jabalain and 18.5 EP10 in El Salam, which were reduced to 7.1 and 11.2 EP10 after treatment, respectively. The corresponding reduction rates were 51.0% and 39.5%. In conclusion, MDA interventions were found to bring about similar relative reduction in prevalence regardless of the baseline value; however, the relative reduction in infection intensity was more salient in the district with a low baseline value for both prevalence and intensity. This clearly points to the importance of repeated MDA interventions in endemic areas, which will eventually contribute to schistosomiasis elimination.

Schistosome and intestinal helminth modulation of macrophage immunometabolism

Macrophages are fundamental to sustain physiological equilibrium and to regulate the pathogenesis of parasitic and metabolic processes. The functional heterogeneity and immune responses of macrophages are shaped by cellular metabolism in response to the host's intrinsic factors, environmental cues and other stimuli during disease. Parasite infections induce a complex cascade of cytokines and metabolites that profoundly remodel the metabolic status of macrophages. In particular, helminths polarize macrophages to an M2 state and induce a metabolic shift towards reliance on oxidative phosphorylation, lipid oxidation and amino acid metabolism. Accumulating data indicate that helminth-induced activation and metabolic reprogramming of macrophages underlie improvement in overall whole-body metabolism, denoted by improved insulin sensitivity, body mass in response to high-fat diet and atherogenic index in mammals. This review aims to highlight the metabolic changes that occur in human and murine-derived macrophages in response to helminth infections and helminth products, with particular interest in schistosomiasis and soil-transmitted helminths.

The IL-33/ST2 Axis in Immune Responses Against Parasitic Disease: Potential Therapeutic Applications

Parasitic infections pose a wide and varying threat globally, impacting over 25% of the global population with many more at risk of infection. These infections are comprised of, but not limited to, toxoplasmosis, malaria, leishmaniasis and any one of a wide variety of helminthic infections. While a great deal is understood about the adaptive immune response to each of these parasites, there remains a need to further elucidate the early innate immune response. Interleukin-33 is being revealed as one of the earliest players in the cytokine milieu responding to parasitic invasion, and as such has been given the name "alarmin." A nuclear cytokine, interleukin-33 is housed primarily within epithelial and fibroblastic tissues and is released upon cellular damage or death. Evidence has shown that interleukin-33 seems to play a crucial role in priming the immune system toward a strong T helper type 2 immune response, necessary in the clearance of some parasites, while disease exacerbating in the context of others. With the possibility of being a double-edged sword, a great deal remains to be seen in how interleukin-33 and its receptor ST2 are involved in the immune response different parasites elicit, and how those parasites may manipulate or evade this host mechanism. In this review article we compile the current cutting-edge research into the interleukin-33 response to toxoplasmosis, malaria, leishmania, and helminthic infection. Furthermore, we provide insight into directions interleukin-33 research may take in the future, potential immunotherapeutic applications of interleukin-33 modulation and how a better clarity of early innate immune system responses involving interleukin-33/ST2 signaling may be applied in development of much needed treatment options against parasitic invaders.

Gene drives for schistosomiasis transmission control

Schistosomiasis is one of the most important and widespread neglected tropical diseases (NTD), with over 200 million people infected in more than 70 countries; the disease has nearly 800 million people at risk in endemic areas. Although mass drug administration is a cost-effective approach to reduce occurrence, extent, and severity of the disease, it does not provide protection to subsequent reinfection. Interventions that target the parasites’ intermediate snail hosts are a crucial part of the integrated strategy required to move toward disease elimination. The recent revolution in gene drive technology naturally leads to questions about whether gene drives could be used to efficiently spread schistosome resistance traits in a population of snails and whether gene drives have the potential to contribute to reduced disease transmission in the long run. Responsible implementation of gene drives will require solutions to complex challenges spanning multiple disciplines, from biology to policy. This Review Article presents collected perspectives from practitioners of global health, genome engineering, epidemiology, and snail/schistosome biology and outlines strategies for responsible gene drive technology development, impact measurements of gene drives for schistosomiasis control, and gene drive governance. Success in this arena is a function of many factors, including gene-editing specificity and efficiency, the level of resistance conferred by the gene drive, how fast gene drives may spread in a metapopulation over a complex landscape, ecological sustainability, social equity, and, ultimately, the reduction of infection prevalence in humans. With combined efforts from across the broad global health community, gene drives for schistosomiasis control could fortify our defenses against this devastating disease in the future.