Scaling severe acute malnutrition treatment with community health workers: a geospatial coverage analysis in rural Mali

BACKGROUND

In 2015, the Ministry of Health in Mali included the treatment of severe acute malnutrition (SAM) into the package of activities of the integrated Community Case Management (iCCM). This paper aims to analyze the impact of including community health workers (CHWs) as treatment providers outside the Health Facilities (HFs) on the coverage of SAM treatment when scaling up the intervention in the three largest districts of the Kayes Region in Mali.

METHODS

A baseline coverage assessment was conducted in August 2017 in the three districts before the CHWs started treating SAM. The end-line assessment was conducted one year later, in August 2018. Coverage was assessed by the standardized methodology called Semi-Quantitative Evaluation of Access and Coverage (SQUEAC). The primary outcome was treatment coverage and other variables evaluated were the geographical distribution of the HFs, CHW's sites and overlapping between both health providers, the estimation of children with geographical access to health care and the estimation of children screened for acute malnutrition in their communities.

RESULTS

Treatment coverage increased in Kayes (28.7-57.1%) and Bafoulabé (20.4-61.1%) but did not in Kita (28.4-28.5%). The decentralization of treatment has not had the same impact on coverage in all districts, with significant differences. The geospatial analyses showed that Kita had a high proportion of overlap between HFs and/or CHWs 48.7% (39.2-58.2), a high proportion of children without geographical access to health care 70.4% (70.1-70.6), and a high proportion of children not screened for SAM in their communities 52.2% (51.9-52.5).

CONCLUSIONS

Working with CHWs in SAM increases treatment coverage, but other critical aspects need to be considered by policymakers if this intervention model is intended to be scaled up at the country level. To improve families' access to nutritional health care, before establishing decentralized treatment in a whole region it must be considered the geographical location of CHWs. This previous assessment will avoid overlap among health providers and ensure the coverage of all unserved areas according to their population densities need.

TRIAL REGISTRATION

ISRCTN registry with ID 1990746. https://doi.org/10.1186/ISRCTN14990746.

The association between child Schistosoma spp. infections and morbidity in an irrigated rice region in Mali: A localized study

Background

Schistosomiasis is one of the neglected tropical diseases endemic to Mali. There has been insufficient investigation of the morbidity burden in highly endemic irrigated rice areas with the ongoing mass drug administration with praziquantel. In February 2005, a year after an initial mass drug administration in 2004, we performed the first cross-sectional survey of schistosomiasis in the Kokry-Bozo village in the Office du Niger rice irrigation region. In the fourteen years since this survey, there has been almost no research into schistosomiasis morbidity in Mali due to lack of funding. Therefore, the 2005 survey supplies near-baseline data for any future research into the treatment impacts in the area.

Methods

One hundred and ninety-four children aged 6–14 years from two schools were assessed for bladder pathology by ultrasound, and for anaemia and micro-haematuria by laboratory tests. Schistosoma eggs were examined microscopically in fresh stool and urine samples. Multivariate logistic regression analysis quantified the association of Schistosoma infections with anaemia, bladder pathology and micro-haematuria. Akaike’s information criterion was used to test the assumption of linear effects of infection intensity classes and used to compare across models.

Results

The overall prevalence of schistosomiasis in 189 school children was 97%; 17% (33/189) had a single infection (S. mansoni,13%, or S. haematobium, 4%) and 80% (156/189) were co-infected with S. mansoni and S. haematobium. The overall prevalence of S. mansoni with light infection was 27% (53/194), moderate infection was 24% (47/194) and heavy infection was 42% (81/194). Of the 194 of children investigated for S. haematobium 59% (114/194) had light infection and 26% (50/194) had heavy infection. No hookworm eggs were detected.

The level of abnormal bladder pathology was 18% (35/189) with the highest found in 10–14 year old children. The prevalence of anaemia was 91% (172/189) and was twice as likely to be associated (OR 2.0, 95% CI 1.1–3.9) with S. mansoni infections than in children without infection. As infection intensity with S. mansoni increased the risk of anaemia (OR 2.0, 95% CI 1.1–3.9) also increased. As infection intensity with S. haematobium increased bladder pathology (OR 2.4, 95%CI 1.3–4.5), haematuria (OR 6.7, 95%CI 3.3–13.6) and micro-haematuria increased (OR 2.4, 95%CI 1.3–4.5).

Conclusion

Our research contributes an important micro-geographical assessment of the heavy burden of schistosomiasis and associated morbidity in children who live in the rice irrigation regions. Our literature review found that there has been very limited research conducted on the impact of the treatment to control morbidity in the ON. Therefore, there is a need to do a comparable, but more extensive, study to identify any changes in morbidity and to indicate current requirements for the control programme. Our results from 2005 called for routine integration of iron supplementation, food fortification and diet diversification into the deworming program.

Inflammation dynamics after praziquantel treatment of Schistosoma haematobium reflected by urinary eosinophil cationic protein

Background

This cohort study assessed urinary eosinophil cationic protein (ECP) as an indicator for urinary tract morbidity and inflammation indication related to single-dose or dual-dose praziquantel (PZQ) treatment.

Methods

Urinary ECP was measured at baseline, 24 h and 9 weeks after treatment (baseline 305, follow-up 204 participants, ages 2-40 years).

Results

ECP was significantly associated with the intensity of infection at baseline (p<0.05). Levels at baseline were 8.31 times higher (p<0.01) in participants with bladder morbidity than in those without. There was no correlation with kidney morbidity and no significant effect of a repeated dose of PZQ 40 mg/kg. Baseline ECP and ECP after 9 weeks were associated with microhaematuria (geometric mean ratio at baseline 7.56 [95% confidence limit {CL} 2.34-24.45]; p<0.01) and macrohaematuria (geometric mean ratio at baseline 6.22 [95% CL 2.71-14.24]; p<0.001). Mean levels of ECP dropped significantly during the first follow-up period and far less so in the second follow-up period (mean ECP at baseline: 70.8 ng/mL; ECP at 24 h: 24.5 ng/mL; ECP at 9 weeks: 14.6 ng/mL).

Conclusion

The urine ECP decrease happened immediately after treatment, reflecting the rapid action of PZQ on eggs in the bladder tissue. ECP in urine can be used as an indirect marker of the degree of local inflammatory reaction in the bladder and is not significantly affected by a repeated dose of PZQ.

Anemia and growth retardation associated with Schistosoma haematobium infection in Mali: a possible subtle impact of a neglected tropical disease

Background

The aim of this cross-sectional study was to investigate a possible association of Schistosoma haematobium with child growth development and describe a plausible schistosomiasis-related anemia in children and adults in a highly schistosomiasis endemic area of Mali.

Methods

Urine, feces and blood samples from 399 participants of both sexes (2-40 years of age) were analyzed and supplemented by anthropometric measurements.

Results

S. haematobium prevalence was 79.8%, S. mansoni 13.2% and Plasmodium falciparum 80.2%. S. haematobium infection intensity as five categories was significantly associated with anemia; i.e., odds of having anemia in the highest and the next highest category was 3.25 (95% CL 1.61-6.55; p<0.01) and 2.45 (95% CL 1.28-4.70; p<0.01), respectively, of that in the three lower categories combined after adjusting for age group and gender and the interaction between the two factors. Anemia was most pronounced in the 2-5 year olds males (55.5%, n=98). P. falciparum infection was not significantly associated with anemia. Stunting (body mass index [BMI] for age z-score<-2.00) was observed in 2.6% (2/78) of the 2-5 years olds and in 7.7% (14/182) in the 6-19 years age group. Lower BMI-z-scores (as continuous variable) were associated with anemia (p<0.05) while high intensity of S. haematobium infection was not significant when adjusting for age group and anemia. Participants with malaria infection had lower z-scores (as continuous variables) of weight and height for age. Lower height for age z-scores were also associated with anemia.

Conclusions

S. haematobium infection is likely to impact on child growth and possibly also anemia in all age groups and advocates for inclusion of whole populations into future control programes.

Organomegaly in Mali before and after praziquantel treatment. A possible association with Schistosoma haematobium

Continuous exposure to schistosome-infested water results in acute and chronic morbidity in all ages. We analysed occurence of organomegaly via ultrasonography and investigated a possible additive effect of dual-dose drug administration in 401 Schistosoma haematobium infected individuals from a highly endemic area in Mali. Mean intensity of infection at baseline (22.0 eggs per 10 ml) was reduced to 0.22 eggs per 10 ml 9 weeks after treatment (both treatments combined). Odds of persistent infection among those given dual-dose treatment was 41% of that in people given single dose (b = 0.41; p = 0.05; 95% CI 0.17-1.00), but after two years, 70.7% of the 157 participants, who completed the survey, were re-infected with no significant difference in prevalence and intensity of infection between treatment groups. Resolution of organomegaly occurred in all age groups after treatment. A novel association between Schistosoma haematobium infection and moderate portal vein enlargement was found in 35% (n: 55). Severe portal vein diameter enlargement was found in 3.2%. After two years, moderate hepatomegaly was present in 50.6%, moderate splenomegaly in 45.6% and moderate portal vein diameter enlargement in 19%. A subsequent dose of PZQ did not provide any additional long-term advantages.

Diagnosis of neglected tropical diseases among patients with persistent digestive disorders (diarrhoea and/or abdominal pain ≥14 days): Pierrea multi-country, prospective, non-experimental case-control study

Background

Diarrhoea still accounts for considerable mortality and morbidity worldwide. The highest burden is concentrated in tropical areas where populations lack access to clean water, adequate sanitation and hygiene. In contrast to acute diarrhoea (<14 days), the spectrum of pathogens that may give rise to persistent diarrhoea (≥14 days) and persistent abdominal pain is poorly understood. It is conceivable that pathogens causing neglected tropical diseases play a major role, but few studies investigated this issue. Clinical management and diagnostic work-up of persistent digestive disorders in the tropics therefore remain inadequate. Hence, important aspects regarding the pathogenesis, epidemiology, clinical symptomatology and treatment options for patients presenting with persistent diarrhoea and persistent abdominal pain should be investigated in multi-centric clinical studies.

Methods/Design

This multi-country, prospective, non-experimental case–control study will assess persistent diarrhoea (≥14 days; in individuals aged ≥1 year) and persistent abdominal pain (≥14 days; in children/adolescents aged 1–18 years) in up to 2000 symptomatic patients and 2000 matched controls. Subjects from Côte d’Ivoire, Indonesia, Mali and Nepal will be clinically examined and interviewed using a detailed case report form. Additionally, each participant will provide a stool sample that will be examined using a suite of diagnostic methods (i.e., microscopic techniques, rapid diagnostic tests, stool culture and polymerase chain reaction) for the presence of bacterial and parasitic pathogens. Treatment will be offered to all infected participants and the clinical treatment response will be recorded. Data obtained will be utilised to develop patient-centred clinical algorithms that will be validated in primary health care centres in the four study countries in subsequent studies.

Discussion

Our research will deepen the understanding of the importance of persistent diarrhoea and related digestive disorders in the tropics. A diversity of intestinal pathogens will be assessed for potential associations with persistent diarrhoea and persistent abdominal pain. Different diagnostic methods will be compared, clinical symptoms investigated and diagnosis-treatment algorithms developed for validation in selected primary health care centres. The findings from this study will improve differential diagnosis and evidence-based clinical management of digestive syndromes in the tropics.

Trial registration

ClinicalTrials.gov; identifier: NCT02105714.

Toward Measuring Schistosoma Response to Praziquantel Treatment with Appropriate Descriptors of Egg Excretion

Background

The control of schistosomiasis emphasizes preventive chemotherapy with praziquantel, which aims at decreasing infection intensity and thus morbidity in individuals, as well as transmission in communities. Standardizing methods to assess treatment efficacy is important to compare trial outcomes across settings, and to monitor program effectiveness consistently. We compared customary methods and looked at possible complementary approaches in order to derive suggestions for standardizing outcome measures.

Methodology/Principal Findings

We analyzed data from 24 studies conducted at African, Asian, and Latin American sites, enrolling overall 4,740 individuals infected with Schistosoma mansoni, S. haematobium, or S. japonicum, and treated with praziquantel at doses of 40–80 mg/kg. We found that group-based arithmetic and geometric means can be used interchangeably to express egg reduction rates (ERR) only if treatment efficacy is high (>95%). For lower levels of efficacy, ERR estimates are higher with geometric than arithmetic means. Using the distribution of individual responses in egg excretion, 6.3%, 1.7% and 4.3% of the subjects treated for S. haematobium, S. japonicum and S. mansoni infection, respectively, had no reduction in their egg counts (ERR = 0). The 5^th, 10^th, and 25^th centiles of the subjects treated for S. haematobium had individual ERRs of 0%, 49.3%, and 96.5%; the corresponding values for S. japonicum were 75%, 99%, and 99%; and for S. mansoni 18.2%, 65.3%, and 99.8%. Using a single rather than quadruplicate Kato-Katz thick smear excluded 19% of S. mansoni-infected individuals. Whilst the effect on estimating ERR was negligible by individual studies, ERR estimates by arithmetic means were 8% lower with a single measurement.

Conclusions/Significance

Arithmetic mean calculations of Schistosoma ERR are more sensitive and therefore more appropriate to monitor drug performance than geometric means. However, neither are satisfactory to identify poor responders. Group-based response estimated by arithmetic mean and the distribution of individual ERRs are correlated, but the latter appears to be more apt to detect the presence and to quantitate the magnitude of suboptimal responses to praziquantel.

To identify whether a person is infected with parasitic worms, stool or urine samples are examined for worm eggs. The drug praziquantel is used against the parasitic disease schistosomiasis. However, there is no definitive agreement as to how the efficacy of praziquantel is best expressed. We put together a database from various studies of the efficacy of praziquantel against schistosomiasis. Efficacy was measured using customary methods: cure rate (CR: percentage of people with eggs in their stool/urine before treatment who became egg-negative after treatment); and egg reduction rate (ERR; percentage reduction in the number of eggs in the stool/urine after treatment, where the mean number of eggs from all people treated is calculated using either geometric or arithmetic means). We found that arithmetic and geometric means can be used interchangeably only if treatment efficacy is very high; arithmetic means are more sensitive to capture drops in efficacy expressed by ERR. A valid complement for drug efficacy monitoring is to study the distribution of individual responses in egg excretion that allows identifying in a single measure both those who had an adequate response to treatment and those who respond less well; e.g., the 5% of the patients with the lowest ERRs.

A late IL-33 response after exposure to Schistosoma haematobium antigen is associated with an up-regulation of IL-13 in human eosinophils

IL-33, a proposed alarmin, stimulates innate immune cells and Th2 cells to produce IL-13 and is rapidly upregulated upon antigen exposure in murine helminth infection. The human IL-33 response to helminth antigen was analysed in Malians infected with Schistosoma haematobium by disrupting parasite integrity via chemotherapy. Plasma IL-33 was measured pretreatment, and 24 h and 9 weeks post-treatment. At 24 h post-treatment, IL-33 levels were low. Nine week post-treatment IL-33 levels were elevated and were associated with an increase in intracellular IL-13 in eosinophils. Up-regulation of intracellular IL-13 in eosinophils was also associated with eosinophil expression of ST2L, the IL-33 receptor. IL-33 may play an important downstream role in the human response to schistosome adult worm antigen exposure.

Rapidly boosted Plasma IL-5 induced by treatment of human Schistosomiasis haematobium is dependent on antigen dose, IgE and eosinophils

Background

IgE specific to worm antigen (SWA) and pre-treatment eosinophil number, are associated with human immunity to re-infection with schistosomes after chemotherapeutic treatment. Treatment significantly elevates circulating IL-5 24-hr post-treatment of Schistosoma mansoni. Here we investigate if praziquantel treatment of human schistosomiasis haematobium also boosts circulating IL-5, the immunological and parasitological factors that predispose to this, and the relationship between these and subsequent immunity to post-treatment re-infection.

Methodology/Principle Findings

The relationship between pre-treatment SWA-IgE, eosinophil number and infection intensity and the 24-hr post-treatment IL-5 boost was investigated in a Malian cohort (aged 5–40 yrs), exposed to S. haematobium. Eotaxin levels were measured at 24-hr post-treatment as a proxy of eosinophil migration. The relationship between the 24-hr post-treatment IL-5 boost and later eosinophil numbers and SWA-IgE levels (9-wk post-treatment) was examined, then investigated in the context of subsequent levels of re-infection (2-yr post-treatment). Circulating IL-5 levels increased 24-hr post-treatment and were associated with pre-treatment infection intensity, SWA-IgE levels, eosinophil number, as well as 24-hr post-treatment eotaxin levels. 24-hr IL-5 levels were, in turn, significantly associated with eosinophil number and elevated SWA-IgE 9-wk later. These SWA-IgE levels were significantly associated with immunity to re-infection.

Conclusions/Significance

Early IL-5 production after treatment-induced exposure to S. haematobium worm antigen is positively associated with antigen dose (infection intensity), IgE availability for arming of effector cells at time of treatment and subsequent eosinophil migration response (as indicated by eotaxin levels). The IL-5 produced is positively associated with increased downstream eosinophil number and increases in specific IgE levels, implicating this cytokine boost and its down-stream consequences in the production and maintenance of IgE, and subsequent re-infection immunity.

Partial human immunity to infection with trematode worms of the genus Schistosoma is associated with IgE specific to adult worm-derived antigens and eosinophils. Treatment studies of Schistosoma infection allow us to examine the temporal features of the immune response post-antigen exposure, their inter-dependence and their relationship with re-infection levels. Here the boosted levels of the cytokine IL-5, measured at 24-hrs post-treatment of a Malian cohort, aged 5–40 yrs, were found to be significantly associated with pre-treatment levels of IgE to worm-derived antigens and eosinophil number, linking this rapid response to two of the main correlates of human immunity to these parasites. The IL-5 levels at 24-hr were in turn related to increased eosinophil counts and SWA-IgE levels at 9-wks post-treatment. In line with previous studies SWA-IgE was associated with resistance to re-infection. The study therefore identifies temporal relationships between immune mediators prior to and post treatment induced antigen exposure that are associated with resistance to re-infection.

Significantly reduced intensity of infection but persistent prevalence of schistosomiasis in a highly endemic region in Mali after repeated treatment

Background

Preventive chemotherapy against schistosomiasis has been implemented since 2005 in Mali, targeting school-age children and adults at high risk. A cross-sectional survey was conducted in 2010 to evaluate the impact of repeated treatment among school-age children in the highly-endemic region of Segou.

Methodology/Principal Findings

The survey was conducted in six sentinel schools in three highly-endemic districts, and 640 school children aged 7–14 years were examined. Infections with Schistosoma haematobium and S. mansoni were diagnosed with the urine filtration and the Kato-Katz method respectively. Overall prevalence of S. haematobium infection was 61.7%, a significant reduction of 30% from the baseline in 2004 (p<0.01), while overall prevalence of S. mansoni infection was 12.7% which was not significantly different from the baseline. Overall mean intensity of S. haematobium and S. mansoni infection was 180.4 eggs/10 ml of urine and 88.2 epg in 2004 respectively. These were reduced to 33.2 eggs/10 ml of urine and 43.2 epg in 2010 respectively, a significant reduction of 81.6% and 51% (p<0.001). The proportion of heavy S. haematobium infections was reduced from 48.8% in 2004 to 13.8% in 2010, and the proportion of moderate and heavy S. mansoni infection was reduced from 15.6% in 2004 to 9.4% in 2010, both significantly (p<0.01). Mathematical modelling suggests that the observed results were in line with the expected changes.

Conclusions/Significance

Significant reduction in intensity of infection on both infections and modest but significant reduction in S. haematobium prevalence were achieved in highly-endemic Segou region after repeated chemotherapy. However, persistent prevalence of both infections and relatively high level of intensity of S. mansoni infection suggest that more intensified control measures be implemented in order to achieve the goal of schistosomiasis elimination. In addition, closer monitoring and evaluation activities are needed in the programme to monitor the drug tolerance and to adjust treatment focus.

Schistosomiasis or bilharzia is caused by infection with the trematode Schistosoma spp. It is widely prevalent in Mali, causing a major public health problem. One of the major control measures is mass treatment of population at risk, particularly school-age children, using the drug praziquantel. Mali started such mass drug treatments in 2005 and a cross-sectional survey was conducted in 2010 in highly endemic region Segou to evaluate the impact of the programme comparing with the baseline data collected in 2004. The repeated treatment significantly reduced the intensity of infection which is closely related to the morbidity of schistosomiasis, however, the prevalence persists with little reduction in the highly endemic region. The results suggest that more intensified control measures be implemented in order to achieve the goal of schistosomiasis elimination, possibly more frequent treatments, improved coverage and improved water and sanitation.

The impact of single versus mixed schistosome species infections on liver, spleen and bladder morbidity within Malian children pre- and post-praziquantel treatment

Background

In the developing world co-infections and polyparasitism within humans appear to be the rule rather than the exception, be it any combination of inter-specific and/or inter- and intra-Genera mixed infections. Mixed infections might generate synergistic or antagonistic interactions and thereby clinically affect individuals and/or impact parasite epidemiology.

Methods

The current study uniquely assesses both Schistosoma mansoni- and Schistosoma haematobium-related morbidity of the liver and the bladder as assessed by ultrasound as well as spleen and liver morbidity through clinical exams. The impact of praziquantel (PZQ) treatment on such potential inter-specific schistosome interactions and resulting morbidity using uniquely detailed longitudinal data (pre- and one year post-PZQ treatment) arising from the National Schistosomiasis Control Program in three areas of Mali: Ségou, Koulikoro and Bamako, is also evaluated. At baseline, data were collected from up to 2196 children (aged 7-14 years), 844 of which were infected with S. haematobium only, 124 with S. mansoni only and 477 with both. Follow-up data were collected from up to 1265 children.

Results

Results suggested lower liver morbidity in mixed compared to single S. mansoni infections and higher bladder morbidity in mixed compared to single S. haematobium infections. Single S. haematobium or S. mansoni infections were also associated with liver and spleen morbidity whilst only single S. haematobium infections were associated with bladder morbidity in these children (light S. haematobium infection OR: 4.3, p < 0.001 and heavy S. haematobium infection OR: 19, p < 0.001). PZQ treatment contributed to the regression of some of the forms of such morbidities.

Conclusions

Whilst the precise biological mechanisms for these observations remain to be ascertained, the results illustrate the importance of considering mixed species infections in any analyses of parasite-induced morbidity, including that for the proposed Disability Adjusted Life Years (DALYs) revised estimates of schistosomiasis morbidity.

Use of Bayesian geostatistical prediction to estimate local variations in Schistosoma haematobium infection in western Africa

OBJECTIVE

To predict the subnational spatial variation in the number of people infected with Schistosoma haematobium in Burkina Faso, Mali and the Niger prior to national control programmes.

METHODS

We used field survey data sets covering a contiguous area 2750 x 850 km and including 26,790 school-age children (5-14 years old) in 418 schools. The prevalence of high- and low-intensity infection and associated 95% credible intervals (CrIs) were predicted using Bayesian geostatistical models. The number infected was determined from the predicted prevalence and the number of school-age children in each km(2).

FINDINGS

The predicted number of school-age children with a low-intensity infection was 433,268 in Burkina Faso, 872,328 in Mali and 580 286 in the Niger. The number with a high-intensity infection was 416,009, 511,845 and 254,150 in each country, respectively. The 95% CrIs were wide: e.g. the mean number of boys aged 10-14 years infected in Mali was 140,200 (95% CrI: 6200-512,100).

CONCLUSION

National aggregate estimates of infection mask important local variations:: e.g. most S. haematobium infections in the Niger occur in the Niger River valley. High-intensity infection was strongly clustered in western and central Mali, north-eastern and northwestern Burkina Faso and the Niger River valley in the Niger. Populations in these foci will carry the bulk of the urinary schistosomiasis burden and should be prioritized for schistosomiasis control. Uncertainties in the predicted prevalence and the numbers infected should be acknowledged by control programme planners.

A comparative study of the spatial distribution of schistosomiasis in Mali in 1984-1989 and 2004-2006

Background

We investigated changes in the spatial distribution of schistosomiasis in Mali following a decade of donor-funded control and a further 12 years without control.

Methodology/Principal Findings

National pre-intervention cross-sectional schistosomiasis surveys were conducted in Mali in 1984–1989 (in communities) and again in 2004–2006 (in schools). Bayesian geostatistical models were built separately for each time period and on the datasets combined across time periods. In the former, data from one period were used to predict prevalence of schistosome infections for the other period, and in the latter, the models were used to determine whether spatial autocorrelation and covariate effects were consistent across periods. Schistosoma haematobium prevalence was 25.7% in 1984–1989 and 38.3% in 2004–2006; S. mansoni prevalence was 7.4% in 1984–1989 and 6.7% in 2004–2006 (note the models showed no significant difference in mean prevalence of either infection between time periods). Prevalence of both infections showed a focal spatial pattern and negative associations with distance from perennial waterbodies, which was consistent across time periods. Spatial models developed using 1984–1989 data were able to predict the distributions of both schistosome species in 2004–2006 (area under the receiver operating characteristic curve was typically >0.7) and vice versa.

Conclusions/Significance

A decade after the apparently successful conclusion of a donor-funded schistosomiasis control programme from 1982–1992, national prevalence of schistosomiasis had rebounded to pre-intervention levels. Clusters of schistosome infections occurred in generally the same areas accross time periods, although the precise locations varied. To achieve long-term control, it is essential to plan for sustainability of ongoing interventions, including stengthening endemic country health systems.

Geostatistical maps are increasingly being used to plan neglected tropical disease control programmes. We investigated the spatial distribution of schistosomiasis in Mali prior to implementation of national donor-funded mass chemotherapy programmes using data from 1984–1989 and 2004–2006. The 2004–2006 dataset was collected after 10 years of schistosomiasis control followed by 12 years of no control. We found that national prevalence of Schistosoma haematobium and S. mansoni was not significantly different in 2004–2006 compared to 1984–1989 and that the spatial distribution of both infections was similar in both time periods, to the extent that models built on data from one time period could accurately predict the spatial distribution of prevalence of infection in the other time period. This has two main implications: that historic data can be used, in the first instance, to plan contemporary control programmes due to the stability of the spatial distribution of schistosomiasis; and that a decade of donor-funded mass distribution of praziquantel has had no discernable impact on the burden of schistosomiasis in subsequent generations of Malians, probably due to rapid reinfection.

Mapping the probability of schistosomiasis and associated uncertainty, West Africa

We aimed to map the probability of Schistosoma haematobium infection being >50%, a threshold for annual mass praziquantel distribution. Parasitologic surveys were conducted in Burkina Faso, Mali, and Niger, 2004–2006, and predictions were made by using Bayesian geostatistical models. Clusters with >50% probability of having >50% prevalence were delineated in each country.

[Geographic distribution and epidemiology of urinary schistosomiasis in Mali: implications for a control program]

A national survey was conducted in Mali between 1986 and 1990 to determine the geographical distribution of urinary schistosomiasis in order to define an ecologically based national schistosomiasis control programme. Fifty six thousand two hundreds and sixty five individuals randomly selected from 323 villages in the nine ecologically defined areas of the whole country were submitted to urine examination using Filtration Technique. In villages along the Niger and Senegal rivers, in the Dogon Plateau and Office du Niger areas, the prevalence of Schistosoma haematobium infection was the highest, respectively 41.8%, 53.1%, 59.4% et 62.9%. In these areas, more 70% of children aged 7 to 14 years were infected. In the Soudanian and North-Soudanian areas, the prevalence were below 10% and respectively only 5.3% and 11.5% of children aged 7 to 14 years were infected. It is concluded that Schistosoma haematobium infection is of public health importance in dam and irrigation areas and in areas along the Niger and Senegal rivers namely in Kayes, Koulikoro, Segou, Mopti regions and in Bamako district. These areas should be considered as priority areas for active control interventions. The interventions should include community-based mass chemotherapy with praziquantel after community diagnostic using urine examination in school aged children and a good monitoring system.

Assessment of ultrasound morbidity indicators of schistosomiasis in the context of large-scale programs illustrated with experiences from Malian children

We assessed morbidity indicators for both Schistosoma haematobium and Schistosoma mansoni infections and evaluated the appropriateness of the World Health Organization (WHO) guidelines for ultrasound in schistosomiasis in the context of large-scale control interventions. Abdominal and urinary tract ultrasonography was performed on 2,247 and 2,822 school children, respectively, from 29 randomly selected schools in Mali before the implementation of mass anthelminthic drug administration. Using two-level logistic regression models, we examined associations of potential factors with the risk of having a positive ultrasound global score (morbidity indicative of S. haematobium infection), abnormal image pattern scores, dilatation of the portal vein, and/or enlarged liver (morbidity indicative of S. mansoni infection). The WHO protocol was found useful for detection of S. haematobium pathology but overestimated the risk of portal vein dilatation and left liver lobe enlargement associated with S. mansoni infection. We conclude that ultrasonography should be included in large-scale control interventions, where logistics allow, but cautiously.

Impact of mass chemotherapy with praziquantel on Schistosoma haematobium and Schistosoma mansoni infections in Office du Niger, Mali

Aims This study was carried up to assess the impact of mass chemotherapy with praziquantel on the prevalence and intensity of Schistosoma haematobium and Schistosoma mansoni in Office du Niger. Materials and Methods It was a cross sectional study with two passages about which we compared a test group of 7 villages (n=2342) treated in 1989 to a control group of 7 villages (n=2263). Results One year after mass chemotherapy, baseline prevalence rates of Schistoosma haematobium, Schistoaoma mansoni and those of the double infection decreased by 50%, 54% and 62,9% respectively. The geometric mean egg counts of Schistosma haematobium (GMECSh) was reduced by 66.6% and that of Schistosoma mansoni (GMECSm) by 43.4%. However, in spite of mass treatment, the overall prevalence rates of Schistosoma haematobium and mansoni were always higher than 20% in young people aged of 6-19 years. Conclusion These data show that in irrigated area, efficacy of praziquantel is strongly affected by age. This persistance of infection in population raises up several questions according to host immunity, parasite biology and praziquantel efficacy.

Evaluation of case management in the integrated schistosomiasis-control programme in Mali

Currently, schistosomiasis control in Mali is mainly based on treatment with praziquantel (PZQ). The policy is to ensure (1). the treatment, every 3 years, of school-age children in all areas where the prevalence of haematuria (an indicator of Schistosoma haematobium infection) in this age-group is >30%, and (2). the sound management of all patients presenting with haematuria or (bloody) diarrhoea (an indicator of S. mansoni infection) at health centres. In the present study, the application of case management was evaluated by visiting 60 healthcare facilities in four geographical areas and interviewing the health-workers at these facilities. The presence of S. haematobium and S. mansoni was reported in the coverage areas of 83% and 37%, respectively, of the healthcare facilities investigated. Health-worker knowledge of the main symptoms of schistosome infection was good and patients exhibiting symptoms attributable to schistosome infection were very likely to receive adequate treatment, particularly (at a frequency of about 80%) when they presented with haematuria. At health-centre level, patients were often directly treated with PZQ, whereas health-workers in district hospitals and private clinics requested a diagnostic test prior to any treatment. PZQ was available in most healthcare facilities but not in the private clinics. The mean cost of treatment of a patient with S. haematobium infection (euro; 2.30) was very similar to the corresponding cost for S. mansoni infection (euro; 2.37). The cost of the PZQ represented approximately 50% of the total costs borne by the patients when presenting at health centres. Patients with the symptoms of S. haematobium infection in Mali can expect adequate diagnosis and treatment in agreement with the recommendations of the World Health Organization. Patients presenting with symptoms related to S. mansoni infection are, however, less likely to be correctly diagnosed. The relatively high costs of treatment and the infrequency with which cases of schistosomiasis seek healthcare necessitate policy decisions, to ensure an affordable and more attractive, clinical system of case management.

Measuring schistosomiasis case management of the health services in Ghana and Mali

The World Health Organization recommends passive case detection by regular health services as a minimum strategy for schistosomiasis morbidity control. To evaluate preparedness of the health systems in Ghana and Mali, we presented four clinical scenarios, two with blood in urine (main early symptom of Schistosoma haematobium) and two with (bloody) diarrhoea (main early symptom of S. mansoni), to health workers. We requested the health personnel for an initial diagnosis and case management strategy without providing information about our primary interest in schistosomiasis. The information was used to determine the chance that a person reporting with symptoms that might have been caused by schistosomiasis would receive praziquantel. All selected health workers participated. Their initial diagnosis was frequently S. haematobium for both scenarios with blood in urine. For the two scenarios with (bloody) diarrhoea, only few mentioned S. mansoni. At health centre level, case management in Mali mainly consisted of direct prescription of medication, whereas in Ghana health workers often referred to a hospital or requested a diagnostic test. The ultimate probability of prescribing praziquantel was relatively high for the scenarios with blood in urine, 60% in Ghana and 75% in Mali, but very low for both scenarios with (bloody) diarrhoea (<20%). Of those health care facilities that would prescribe praziquantel, 60% (Ghana) and 80% (Mali) had it in stock. In conclusion, the clinical scenario study showed that patients reporting with blood in urine will be treated with praziquantel at approximately half of the health care facilities, whereas of those presenting with (bloody) diarrhoea only few would receive treatment with praziquantel. Considering these facts, it is questionable if passive case detection is a sufficient basis for effective schistosomiasis morbidity control, especially for S. mansoni infection.

Assessment of cure by detection of circulating antigens in serum and urine, following schistosomiasis mass treatment in two villages of the Office du Niger, Mali

Eight weeks after mass chemotherapy with 40 mg/kg praziquantel in two villages in Office du Niger (an irrigation area in Mali, endemic for both Schistosoma haematobium and Schistosoma mansoni) the circulating anodic (CAA) and cathodic (CCA) antigen detection assays were carried out on serum and urine samples. Both prior and post treatment highest prevalence was measured with the urine-CCA assay. Cure rates determined by antigen detection were almost half that of the egg counting methods. It was shown that the reduction in intensity should be preferentially assessed by the serum-CAA assay. Compared with egg detection, a single antigen detection assay gave a much better assessment of the impact of chemotherapy.

Circulating anodic and cathodic antigen in serum and urine of mixed Schistosoma haematobium and S. mansoni infections in Office du Niger, Mali

In Office du Niger, an area endemic for both Schistosoma haematobium and S. mansoni in Mali, circulating anodic (CAA) and cathodic (CCA) antigen detection assays were performed on pretreatment serum and urine samples from two villages, Rigandé and Siguivoucé, and compared with egg counting methods. The highest prevalence was obtained with the urine-CCA assay which also had the highest sensitivity to S. haematobium, S. mansoni or mixed infection. A single urine-CCA assay was as sensitive as repeated egg counts (one stool+two urine examinations per individual). When the different assays were tested in parallel, several combinations including assays on serum were found to be highly sensitive. As urine sampling is widely accepted, urine assays will be used for further monitoring these villages one and two years after chemotherapy.

Comparison of the circulating anodic antigen detection assay and urine filtration to diagnose Schistosoma haematobium infections in Mali

The applicability of a circulating Schistosoma antigen detection assay for determining rates of infection and efficacy of chemotherapy was evaluated in Mali. Urine egg counts were compared to circulating anodic antigen enzyme-linked immunosorbent assay (CAA-ELISA) titres in serum, before and 6 weeks after treatment with a single dose of praziquantel (40 mg/kg), in 2 villages in Dogon Country, an area endemic for S. haematobium, the predominant schistosome infection in Mali. In Kassa, a village with a moderate prevalence of infection, the serological prevalence (48%) was significantly higher than the parasitological prevalence (31%). In Boro, a village with high parasitological prevalence (76%), no difference was observed between the results of both methods (prevalence by CAA-ELISA was 75%). Cure rates estimated by CAA-ELISA were lower than those determined parasitologically, suggesting that cure rates are overestimated by egg counting. The sensitivity of the CAA-ELISA was 78%. In both villages, before treatment, a positive correlation was found between the number of eggs in urine and serum CAA titres. It is concluded that, although further simplification and improvement of the sensitivity of the assay is needed, in its present ELISA format the antigen detection assay is useful for monitoring sentinel populations. Furthermore, the serum CAA assay performed adequately in a public health laboratory within an endemic country.

Schistosomiasis in Dogon country, Mali: identification and prevalence of the species responsible for infection in the local community

The prevalence of schistosomiasis amongst the Dogon people in 4 villages and one school of the Bankass district of Mali was determined during 2 surveys in 1992; 1398 urine and 1199 stool samples were examined. The most common schistosome was Schistosoma haematobium, with an overall prevalence of 51.3%; S. mansoni had a prevalence of 12%. No S. intercalatum egg was seen in the stools. Biomphalaria pfeifferi and Bulinus truncatus were found in pools at the base of the Dogon cliffs; Bulinus forskalii was found in smaller numbers in brick pits. Two isolates from urine samples of children were identified as S. haematobium in the laboratory using an alpha-glycerophosphate marker, restriction enzyme analysis of ribosomal deoxyribonucleic acid (rDNA) and random amplification of polymorphic DNA. The isolates did not develop in Bulinus forskalii or B. crystallinus of the B. forskalii group. Some evidence for past hybridization of S. haematobium and S. intercalatum is provided by the enzyme and rDNA results as well as the positive Ziehl-Neelsen staining of polymorphic eggs in urine samples. The findings are discussed in relation to the published observations concerning schistosomiasis in travellers returning from this region of Mali.