Epidemiology of schistosomiasis in Gezira area Central Sudan and analysis of cytokine profiles

Programmatic Implications for Schistosomiasis Elimination Based on Community-Based Survey in the Blue Nile, North Kordofan, and Sennar States, Sudan

Schistosomiasis prevalence has remained high in some areas due to reinfection despite repeated mass drug administration interventions. We aimed to explore its risk factors in order to help to design adequate interventions in such high-transmission areas. A total of 6225 individuals residing in 60 villages in 8 districts of North Kordofan, Blue Nile, or Sennar States, Sudan participated in the community-based survey in March 2018. First, we investigated Schistosoma haematobium and Schistosoma mansoni prevalences among school-aged children and adults. Second, the associations between risk factors and schistosomiasis were explored. Those without any type of latrine in their households had higher odds of being infected with schistosomiasis than those with a latrine (odds ratio (OR) = 1.53; 95% confidence interval (CI) 1.20-1.94; p = 0.001), and the odds of being positive for schistosomiasis among people living in a household without an improved latrine were higher than for their counterparts with an improved latrine (OR = 1.63; CI 1.05-2.55; p = 0.03). Furthermore, people with households or outside compounds found to contain human faeces had higher odds of being infected with schistosomiasis than their counterparts (OR = 1.36, 95% CI 1.01-1.83, p = 0.04). Installing an improved latrine and eliminating open defecation should be highlighted in schistosomiasis elimination projects in high-transmission areas.

Association Between the Prevalence of Schistosomiasis in Elementary School Students and Their Parental Occupation in Sudan

Global efforts to identify groups at high risk for schistosomiasis have mainly concentrated on identifying their geographical distribution. Investigations on the socioeconomic characteristics of high-risk groups are relatively scarce. This study aimed to explore the associations between schistosomiasis among students and their parents’ occupations. A nationwide cross-sectional survey was conducted targeting 105,167 students in 1,772 primary schools across Sudan in 2017. From these students, 100,726 urine and 96,634 stool samples were collected to test for Schistosoma haematobium and S. mansoni infection. A multi-level mixed effect analysis was used with age and sex as fixed factors, and school as a random factor. The odd ratios (ORs) of practicing open defecation among farmers’ children were almost 5 times higher than their counterparts whose parents were government officials (OR=4.97, 95% confidence intervals (CIs): 4.57-5.42, P<0.001). The ORs of contacting water bodies for watering livestock among farmers’ children were more than 4 times higher than those of children whose parents were government officials (OR=4.59, 95% CIs: 4.02-5.24, P<0.001). This study shows that schistosomiasis represents a disease of poverty and that farmers’ children constituted a high-risk group.

Does the presence of praziquantel-related adverse events affect the health community's perception toward the mass chemopreventive program in the highest prevalence area of Schistosomiasis in Indonesia? Study in Dodolo village, Napu Valley, Central Sulawesi

OBJECTIVE

This study was to determine the relationship between a praziquantel-related adverse event with the health community perception to chemopreventive of Schistosomiasis in Dodolo village, Napu Valley, Central Sulawesi.

METHODS

A cross-sectional study was conducted among the 79 residents of Dodolo village, who following praziquantel-mass drug administration. A-questionnaire was used to collect demographic information of the subject who participated in the study, the presence of treatment-related symptoms, and community perception. The health perception was based on the health belief model (HBM) framework. Data were analyzed using Chi-square.

RESULT

The incidence of praziquantel-related adverse events was 92% (73), with the highest frequency were nausea (69%), vomit (57%), and headache (47%). The total number of treatments related to symptoms was significantly correlated with age (p 0.030). 78% (62) of participants had a supportive perceived susceptibility, 71% (56) participants had a supportive perceived severity, 63% (50) participants had supportive perceived benefits, meanwhile 58% (46) had a not supportive perceived barrier to praziquantel mass drug administration. The presence of praziquantel-related adverse events was significantly correlated with a perceived barrier of the participant to the chemopreventive program.

CONCLUSION

The Dodolo community had a supportive health perception for the success of the Schistosomiasis elimination program, despite the high frequency of adverse events after praziquantel consumption.

Previous History of American Tegumentary Leishmaniasis Alters Susceptibility and Immune Response Against Schistosoma mansoni Infection in Humans

Schistosomiasis and Leishmaniasis are chronic parasitic diseases with high prevalence in some tropical regions and, due to their wide distribution, a risk of co-infections is present in some areas. Nevertheless, the impact of this interaction on human populations is still poorly understood. Thus, the current study evaluated the effect of previous American Tegumentary Leishmaniasis (ATL) on the susceptibility and immune response to Schistosoma mansoni infection in residents from a rural community in Northern of Minas Gerais state, Brazil, an area endemic for both parasitic infections. The participants answered a socioeconomic questionnaire and provided stool and blood samples for parasitological and immunological evaluations. Stool samples were examined by a combination of parasitological techniques to identify helminth infections, especially S. mansoni eggs. Blood samples were used for hemograms and to measure the serum levels of cytokines and chemokines. Reports on previous ATL were obtained through interviews, clinical evaluation forms, and medical records. S. mansoni infection was the most prevalent parasitic infection in the study population (46%), and the majority of the infected individuals had a very low parasite burden. In the same population, 93 individuals (36.2%) reported previous ATL, and the prevalence of S. mansoni infection among these individuals was significantly higher than among individuals with no ATL history. A multiple logistic regression model revealed that S. mansoni infection was positively associated with higher levels of CCL3 and CCL17, and a higher frequency of IL-17 responders. Moreover, this model demonstrated that individuals with an ATL history had a 2-fold higher probability to be infected with S. mansoni (OR = 2.0; 95% CI 1.04–3.68). Among S. mansoni-infected individuals, the logistic regression demonstrated that a previous ATL history was negatively associated with the frequency of IL-17 responders and CXCL10 higher responders, but positively associated with higher IL-27 responders. Altogether, our data suggest that previous ATL may alter the susceptibility and the immune response in S. mansoni-infected individuals, which may likely affect the outcome of schistosomiasis and the severity of the disease in humans.

Schistosoma mansoni PCR+ -infected individuals in the Sudan present elevated systemic levels of chemokines when compared to uninfected and egg+ cohorts

Infections with Schistosoma mansoni remain a major health problem in the Sudan where endemic communities, such as those in Kassala and Khartoum states, continue to face severe social-economic difficulties. Our previous immunoepidemiological findings revealed different immune [cytokine and S. mansoni egg (SEA) antibody] profiles in individuals with active infections (eggs in stool n = 110), individuals positive for S. mansoni via polymerase chain reaction (PCR) using sera (SmPCR⁺ n = 63) and those uninfected (Sm uninf). As antibody responses to eggs and worms are known to change during infection, we have expanded the profiling further by determining levels of adult worm (SWA) antibodies and nine chemokines in the serum of each individual in the three different cohorts. With the exception of C-C motif chemokine ligand (CCL)2, all measured chemokines were significantly higher in SmPCR⁺ individuals when compared to the egg⁺ group and in addition they also presented elevated levels of SWA-specific immunoglobulin (Ig)G2. Multivariable regression analysis further revealed that infection per se was strongly linked to SWA-specific IgG3 levels and CCL5 was strongly associated with a SmPCR⁺ diagnostic state. In the absence of PCR diagnostics that recognize juvenile worms or schistosomulae motives, identifying schistosome-specific traits should provide better insights into current prevalence rates in endemic communities and, in doing so, take into consideration PCR⁺ non-egg⁺ individuals in current treatment programmes.

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

Objective

Schistosomiasis remains one of the most common parasitic diseases worldwide. This is a cross-sectional study aimed to determine the prevalence of schistosomiasis and its associated risk factors among primary school children in Um-Asher area. The study was conducted among 170 primary school students in Um-Asher area from November 2017 to February 2018. Urine and stool samples were collected and examined for schistosomiasis infections. Moreover, data on sociodemographic characteristics and associated risk factors were obtained using a questionnaire.

Results

The overall prevalence of Schistosoma haematobium was 12.9%, whereas that of Schistosoma mansoni was 2.95%. Additionally, the males had higher prevalence (60%) of S. mansoni than females (40%). However, both gender were equally infected with S. haematobium (50%). With regard to risk factors, distance of residence from water source and source of drinking water are relatively associated with the infection.

Pattern and outcome of acute kidney injury among Sudanese adults admitted to a tertiary level hospital: a retrospective cohort study

Introduction

Little is known about the pattern and outcome of Acute Kidney injury (AKI) in Sudan. This study aimed to determine the etiology and outcome of AKI among Sudanese adults.

Methods

A retrospective cohort study was conducted in a tertiary level hospital, Soba University Hospital, Sudan. The medical records of all adults admitted to hospital from the 1^st of January to 31^st of December 2014 were reviewed. The diagnosis and severity of AKI was defined as per the Kidney Disease Improving Global Outcomes (KDIGO) recommendations.

Results

The medical records of 6769 patients were reviewed. AKI was diagnosed in 384 patients (5.7%); being community acquired in 82.6% of cases. Sepsis, volume depletion, obstructive uropathy, heart failure, acute glomerulonephritis and severe malaria were the commonest causes of AKI diagnosed in 44%, 38.5%, 8.9%, 5.7%, 4.7% and 3.1% of patients, respectively. Following treatment complete renal recovery was seen in 35.7% of patients; whereas 31.2% of patients died. Predictors of increased risk of death were old age [OR 1.03, 95% CI (1.01-1.057); P=0.003], presence of chronic liver disease [OR 2.877, 95% CI (1.5-5.5); P=0.001], sepsis [OR 2.51, 95% CI (1.912-4.493);P=0.002] and the severity of AKI [OR 3.873, 95% CI(1.498-10.013);P=0.005].

Conclusion

AKI was diagnosed in 5.7% of adults admitted to hospital. Most patients were having community acquired AKI. Old age, the presence of chronic liver disease, sepsis, and the severity of AKI as per KDIQO staging were significant predictors of mortality.

Multivariable Regression Analysis in Schistosoma mansoni-Infected Individuals in the Sudan Reveals Unique Immunoepidemiological Profiles in Uninfected, egg+ and Non-egg+ Infected Individuals

BACKGROUND

In the Sudan, Schistosoma mansoni infections are a major cause of morbidity in school-aged children and infection rates are associated with available clean water sources. During infection, immune responses pass through a Th1 followed by Th2 and Treg phases and patterns can relate to different stages of infection or immunity.

METHODOLOGY

This retrospective study evaluated immunoepidemiological aspects in 234 individuals (range 4-85 years old) from Kassala and Khartoum states in 2011. Systemic immune profiles (cytokines and immunoglobulins) and epidemiological parameters were surveyed in n = 110 persons presenting patent S. mansoni infections (egg+), n = 63 individuals positive for S. mansoni via PCR in sera but egg negative (SmPCR+) and n = 61 people who were infection-free (Sm uninf). Immunoepidemiological findings were further investigated using two binary multivariable regression analysis.

PRINCIPAL FINDINGS

Nearly all egg+ individuals had no access to latrines and over 90% obtained water via the canal stemming from the Atbara River. With regards to age, infection and an egg+ status was linked to young and adolescent groups. In terms of immunology, S. mansoni infection per se was strongly associated with increased SEA-specific IgG4 but not IgE levels. IL-6, IL-13 and IL-10 were significantly elevated in patently-infected individuals and positively correlated with egg load. In contrast, IL-2 and IL-1β were significantly lower in SmPCR+ individuals when compared to Sm uninf and egg+ groups which was further confirmed during multivariate regression analysis.

CONCLUSIONS/SIGNIFICANCE

Schistosomiasis remains an important public health problem in the Sudan with a high number of patent individuals. In addition, SmPCR diagnostics revealed another cohort of infected individuals with a unique immunological profile and provides an avenue for future studies on non-patent infection states. Future studies should investigate the downstream signalling pathways/mechanisms of IL-2 and IL-1β as potential diagnostic markers in order to distinguish patent from non-patent individuals.

Prevalence, risk factors, and clinical manifestations of schistosomiasis among school children in the White Nile River basin, Sudan

Background

We investigated the prevalence, risk factors, and clinical manifestations of schistosomiasis in White Nile State, Sudan, to determine the local characteristics of schistosomiasis in the White Nile River basin.

Methods

Urine and stool samples were collected from 338 students (176 boys, 162 girls) at three primary schools and were examined using the urine filtration method and the Kato-Katz technique, respectively. Of the students, 200 were interviewed using a semi-structured questionnaire to assess water-contact patterns and health conditions related with urinary schistosomiasis.

Results

Of the 338 students, egg-positive rates for S. haematobium and S. mansoni were 45.0% and 5.9%, respectively, and 4.4% were mixed. The intensities of S. haematobium and S. mansoni infection were 1.091 ± 0.744 log EP10 (eggs per 10 mL of urine, mean ± SD = 57 ± 172 EP10) and 1.787 ± 0.844 log EPG (eggs per gram of stool, mean ± SD = 156 ± 176 EPG), respectively. The prevalence and intensity of S. haematobium infection differed significantly among the three schools, but not by gender or age. Urinary schistosomiasis was significantly associated with the frequencies of contaminated water contact, taking baths, swimming, and wading the stream; however, frequencies of these events were not significantly correlated with infection intensity. Self-reported hematuria and dysuria also correlated significantly with urinary schistosomiasis.

Conclusions

The overall prevalence of schistosomiasis, especially urinary schistosomiasis, is high in the White Nile River basin, Sudan, and is closely associated with frequencies of water contact, taking baths, swimming, and wading the stream. We strongly recommend implementation of an integrated schistosomiasis control program in this area.

Host determinants of reinfection with schistosomes in humans: a systematic review and meta-analysis

Background

Schistosomiasis is still a major public health burden in the tropics and subtropics. Although there is an effective chemotherapy (Praziquantel) for this disease, reinfection occurs rapidly after mass drug administration (MDA). Because the entire population do not get reinfected at the same rate, it is possible that host factors may play a dominant role in determining resistance or susceptibility to reinfection with schistosomes. Here, we systematically reviewed and meta-analyzed studies that reported associations between reinfection with the principal human-infecting species (S. mansoni, S. japonicum and S. haematobium) and host socio-demographic, epidemiological, immunological and genetic factors.

Methodology/Principal Findings

PubMed, Scopus, Google Scholar, Cochrane Review Library and African Journals Online public databases were searched in October 2013 to retrieve studies assessing association of host factors with reinfection with schistosomes. Meta-analysis was performed to generate pooled odds ratios and standardized mean differences as overall effect estimates for dichotomous and continuous variables, respectively. Quality assessment of included studies, heterogeneity between studies and publication bias were also assessed. Out of the initial 2739 records, 109 studies were included in the analyses, of which only 32 studies with 37 data sets were eligible for quantitative data synthesis. Among several host factors identified, strong positive association was found with age and pre-treatment intensity, and only slightly for gender. These factors are major determinants of exposure and disease transmission. Significant positive association was found with anti-SWA IgG4 level, and a negative overall effect for association with IgE levels. This reconfirmed the concept that IgE/IgG4 balance is a major determinant of protective immunity against schistosomiasis. Other identified determinants were reported by a small number of studies to enable interpretation.

Conclusions

Our data contribute to the understanding of host-parasite interaction as it affects reinfection, and is a potential tool to guide planning and tailoring of community interventions to target high-risk groups.

One of the major challenges of schistosomiasis control is that disease prevalence reverts to baseline levels after mass drug administration due to high rate of reinfection. Host factors play a major role in determining resistance or susceptibility to reinfection with schistosomiasis and other diseases. We systematically searched and analyzed studies that identified potential host determinants of reinfection with schistosomes. Among demographic variables, age but not gender was strongly associated with reinfection with schistosomes. Pretreatment infection intensity was also identified as a major determinant of reinfection. Positive association with IgG4 levels and negative association with IgE levels reconfirmed the notion that IgE/IgG4 balance is the major factor controlling protective immunity against schistosomiasis. Other factors were reported by few studies to allow correct inferences. These results contribute to our understanding of host-parasite relationship as it affects reinfection, and will be useful for planning and targeting the limited resources for intervention on high-risk groups.