Sustained preventive chemotherapy for soil-transmitted helminthiases leads to reduction in prevalence and anthelminthic tablets required

Abstract Background The goal of soil-transmitted helminthiases (STH) control programmes is to eliminate STH-associated morbidity in the target population by reducing the prevalence of moderate- and heavy-intensity infections and the overall STH infection prevalence mainly through preventive chemotherapy (PC) with either albendazole or mebendazole. Endemic countries should measure the success of their control programmes through regular epidemiological assessments. We evaluated changes in STH prevalence in countries that conducted effective PC coverage for STH to guide changes in the frequency of PC rounds and the number of tablets needed. Methods We selected countries from World Health Organization (WHO)‘s Preventive Chemotherapy and Transmission control (PCT) databank that conducted ≥5 years of PC with effective coverage for school-age children (SAC) and extracted STH baseline and impact assessment data using the WHO Epidemiological Data Reporting Form, Ministry of Health reports and/or peer-reviewed publications. We used pooled and weighted means to plot the prevalence of infection with any STH and with each STH species at baseline and after ≥5 years of PC with effective coverage. Finally, using the WHO STH decision tree, we estimated the reduction in the number of tablets needed. Results Fifteen countries in four WHO regions conducted annual or semi-annual rounds of PC for STH for 5 years or more and collected data before and after interventions. At baseline, the pooled prevalence was 48.9% (33.1–64.7%) for any STH, 23.2% (13.7–32.7%) for Ascaris lumbricoides, 21.01% (9.7–32.3%) for Trichuris trichiura and 18.2% (10.9–25.5%) for hookworm infections, while after ≥5 years of PC for STH, the prevalence was 14.3% (7.3–21.3%) for any STH, 6.9% (1.3–12.5%) for A. lumbricoides, 5.3% (1.06–9.6%) for T. trichiura and 8.1% (4.0–12.2%) for hookworm infections. Conclusions Countries endemic for STH have made tremendous progress in reducing STH-associated morbidity, but very few countries have data to demonstrate that progress. In this study, the data show that nine countries should adapt their PC strategies and the frequency of PC rounds to yield a 36% reduction in drug needs. The study also highlights the importance of impact assessment surveys to adapt control strategies according to STH prevalence.

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Associations between infection intensity categories and morbidity prevalence in school-age children are much stronger for Schistosoma haematobium than for S. mansoni

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009444 ◽

2021 ◽

Vol 15 (5) ◽

pp. e0009444

Author(s):

Ryan E. Wiegand ◽

W. Evan Secor ◽

Fiona M. Fleming ◽

Michael D. French ◽

Charles H. King ◽

...

Keyword(s):

Ultrasound Image ◽

Infection Intensity ◽

Control Program ◽

Monitoring And Evaluation ◽

World Health ◽

Current Status ◽

School Age Children ◽

School Age ◽

Preventive Chemotherapy ◽

Urogenital Schistosomiasis

Background World Health Organization (WHO) guidelines for measuring global progress in schistosomiasis control classify individuals with Schistosoma spp. infections based on the concentration of excreted eggs. We assessed the associations between WHO infection intensity categories and morbidity prevalence for selected S. haematobium and S. mansoni morbidities in school-age children. Methodology A total of 22,488 children aged 6–15 years from monitoring and evaluation cohorts in Burkina Faso, Mali, Niger, Uganda, Tanzania, and Zambia from 2003–2008 were analyzed using Bayesian logistic regression. Models were utilized to evaluate associations between intensity categories and the prevalence of any urinary bladder lesion, any upper urinary tract lesion, microhematuria, and pain while urinating (for S. haematobium) and irregular hepatic ultrasound image pattern (C-F), enlarged portal vein, laboratory-confirmed diarrhea, and self-reported diarrhea (for S. mansoni) across participants with infection and morbidity data. Principal findings S. haematobium infection intensity categories possessed consistent morbidity prevalence across surveys for multiple morbidities and participants with light infections had elevated morbidity levels, compared to negative participants. Conversely, S. mansoni infection intensity categories lacked association with prevalence of the morbidity measures assessed. Conclusions/significance Current status infection intensity categories for S. haematobium were associated with morbidity levels in school-age children, suggesting urogenital schistosomiasis morbidity can be predicted by an individual’s intensity category. Conversely, S. mansoni infection intensity categories were not consistently indicative of childhood morbidity at baseline or during the first two years of a preventive chemotherapy control program.

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No Evidence of SARS-CoV-2 Circulation in Rome (Italy) during the Pre-Pandemic Period: Results of a Retrospective Surveillance

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17228461 ◽

2020 ◽

Vol 17 (22) ◽

pp. 8461

Author(s):

Carlo Capalbo ◽

Enrico Bertamino ◽

Alessandro Zerbetto ◽

Iolanda Santino ◽

Andrea Petrucca ◽

...

Keyword(s):

Control Strategies ◽

Local Level ◽

Central Italy ◽

Total Sample ◽

World Health ◽

Infection Prevalence ◽

Health Authorities ◽

Causative Agents ◽

Definition Of ◽

Health Organization

In March 2020, the World Health Organization (WHO) declared that the COVID-19 outbreak recorded over the previous months could be characterized as a pandemic. The first known Italian SARS-CoV-2 positive case was reported on 21 February. In some countries, cases of suspected “COVID-19-like pneumonia” had been reported earlier than those officially accepted by health authorities. This has led many investigators to check preserved biological or environmental samples to see whether the virus was detectable on dates prior to those officially stated. With regard to Italy, the results of a microbiological screening in sewage samples collected between the end of February and the beginning of April 2020 from wastewaters in Milan (Northern Italy) and Rome (Central Italy) showed presence of SARS-CoV-2. In the present study, we evaluated, by means of a standardized diagnostic method, the SARS-CoV-2 infection prevalence amongst patients affected by severe acute respiratory syndrome (SARI) in an academic hospital located in Central Italy during the period of 1 November 2019–1 March 2020. Overall, the number of emergency room (ER) visits during the investigated period was 13,843. Of these, 1208 had an influenza-like syndrome, but only 166 matched the definition of SARI as stated in the study protocol. A total of 52 SARI cases were laboratory confirmed as influenza: 26 as a type B virus, 25 as a type A, and 1 as both viruses. Although about 17% of the total sample had laboratory or radiological data compatible with COVID-19, all the nasopharyngeal swabs stored underwent SARS-CoV-2 RT-PCR and tested negative. Based on our result, it is confirmed that the COVID-19 pandemic spread did not start prior to the “official” onset in central Italy. Routine monitoring of SARI causative agents at the local level is critical for reporting epidemiologic and etiologic trends that may differ from one country to another and also among different influenza seasons. This has a practical impact on prevention and control strategies.

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Comparing parasitological vs serological determination of Schistosoma haematobium infection prevalence in preschool and primary school-aged children: implications for control programmes

Parasitology ◽

10.1017/s0031182014000213 ◽

2014 ◽

Vol 141 (14) ◽

pp. 1962-1970 ◽

Cited By ~ 18

Author(s):

WELCOME M. WAMI ◽

NORMAN NAUSCH ◽

KATHARINA BAUER ◽

NICHOLAS MIDZI ◽

REGGIS GWISAI ◽

...

Keyword(s):

Primary School ◽

Schistosoma Haematobium ◽

Age Groups ◽

Diagnostic Methods ◽

World Health ◽

Infection Prevalence ◽

Serological Method ◽

Treatment Regimens ◽

School Aged Children ◽

Control Programmes

SUMMARYTo combat schistosomiasis, the World Health Organization (WHO) recommends that infection levels are determined prior to designing and implementing control programmes, as the treatment regimens depend on the population infection prevalence. However, the sensitivity of the parasitological infection diagnostic method is less reliable when infection levels are low. The aim of this study was to compare levels of Schistosoma haematobium infection obtained by the parasitological method vs serological technique. Infection levels in preschool and primary school-aged children and their implications for control programmes were also investigated. Infection prevalence based on serology was significantly higher compared with that based on parasitology for both age groups. The difference between infection levels obtained using the two methods increased with age. Consequentially, in line with the WHO guidelines, the serological method suggested a more frequent treatment regimen for this population compared with that implied by the parasitological method. These findings highlighted the presence of infection in children aged ⩽5 years, further reiterating the need for their inclusion in control programmes. Furthermore, this study demonstrated the importance of using sensitive diagnostic methods as this has implications on the required intervention controls for the population.

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Economic evaluations of human schistosomiasis interventions: a systematic review and identification of associated research needs

Wellcome Open Research ◽

10.12688/wellcomeopenres.15754.1 ◽

2020 ◽

Vol 5 ◽

pp. 45 ◽

Cited By ~ 3

Author(s):

Hugo C. Turner ◽

Michael D. French ◽

Antonio Montresor ◽

Charles H. King ◽

David Rollinson ◽

...

Keyword(s):

Systematic Review ◽

Neglected Tropical Diseases ◽

Control Strategies ◽

Scale Up ◽

Cost Benefit ◽

Preventive Treatment ◽

World Health ◽

Economic Evaluations ◽

Preventive Chemotherapy ◽

Human Schistosomiasis

Background: Schistosomiasis is one of the most prevalent neglected tropical diseases (NTDs) with an estimated 229 million people requiring preventive treatment worldwide. Recommendations for preventive chemotherapy strategies have been made by the World Health Organization (WHO) whereby the frequency of treatment is determined by the settings prevalence. Despite recent progress, many countries still need to scale up treatment and important questions remain regarding optimal control strategies. This paper presents a systematic review of the economic evaluations of human schistosomiasis interventions. Methods: A systematic review of the literature was conducted on 22nd August 2019 using the PubMed (MEDLINE) and ISI Web of Science electronic databases. The focus was economic evaluations of schistosomiasis interventions, such as cost-effectiveness and cost-benefit analyses. No date or language stipulations were applied to the searches. Results: We identified 53 relevant health economic analyses of schistosomiasis interventions. Most studies related to Schistosoma japonicum followed by S. haematobium. Several studies also included other NTDs. In Africa, most studies evaluated preventive chemotherapy, whereas in China they mostly evaluated programmes using a combination of interventions (such as chemotherapy, snail control and health education). There was wide variation in the methodology and epidemiological settings investigated. A range of effectiveness metrics were used by the different studies. Conclusions: Due to the variation across the identified studies, it was not possible to make definitive policy recommendations. Although, in general, the current WHO recommended preventive chemotherapy approach to control schistosomiasis was found to be cost-effective. This finding has important implications for policymakers, advocacy groups and potential funders. However, there are several important inconsistencies and research gaps (such as how the health benefits of interventions are quantified) that need to be addressed to identify the resources required to achieve schistosomiasis control and elimination.

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Urogenital schistosomiasis infection prevalence targets to determine elimination as a public health problem based on microhematuria prevalence in school-age children

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009451 ◽

2021 ◽

Vol 15 (6) ◽

pp. e0009451

Author(s):

Ryan E. Wiegand ◽

Fiona M. Fleming ◽

Anne Straily ◽

Susan P. Montgomery ◽

Sake J. de Vlas ◽

...

Keyword(s):

Public Health ◽

Health Problem ◽

Public Health Problem ◽

School Age Children ◽

Infection Prevalence ◽

School Age ◽

Infection Level ◽

Preventive Chemotherapy ◽

Urogenital Schistosomiasis ◽

Morbidity Control

Background Recent research suggests that schistosomiasis targets for morbidity control and elimination as a public health problem could benefit from a reanalysis. These analyses would define evidence-based targets that control programs could use to confidently assert that they had controlled or eliminated schistosomiasis as a public health problem. We estimated how low Schistosoma haematobium infection levels diagnosed by urine filtration in school-age children should be decreased so that microhematuria prevalence was at, or below, a “background” level of morbidity. Methodology Data obtained from school-age children in Burkina Faso, Mali, Niger, Tanzania, and Zambia who participated in schistosomiasis monitoring and evaluation cohorts were reanalyzed before and after initiation of preventive chemotherapy. Bayesian models estimated the infection level prevalence probabilities associated with microhematuria thresholds ≤10%, 13%, or 15%. Principal findings An infection prevalence of 5% could be a sensible target for urogenital schistosomiasis morbidity control in children as microhematuria prevalence was highly likely to be below 10% in all surveys. Targets of 8% and 11% infection prevalence were highly likely to result in microhematuria levels less than 13% and 15%, respectively. By contrast, measuring heavy-intensity infections only achieves these thresholds at impractically low prevalence levels. Conclusions/Significance A target of 5%, 8%, or 11% urogenital schistosomiasis infection prevalence in school-age children could be used to determine whether a geographic area has controlled or eliminated schistosomiasis as a public health problem depending on the local background threshold of microhematuria.

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Control programs for strongyloidiasis in areas of high endemicity: an economic analysis of different approaches

Infectious Diseases of Poverty ◽

10.1186/s40249-021-00858-9 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Dora Buonfrate ◽

Lorenzo Zammarchi ◽

Zeno Bisoffi ◽

Antonio Montresor ◽

Sara Boccalini

Keyword(s):

Strongyloides Stercoralis ◽

World Health ◽

Health Priorities ◽

School Age Children ◽

First Year ◽

Preventive Chemotherapy ◽

United States Dollar ◽

Base Scenario ◽

Case Base ◽

The Impact

Abstract Background Implementation of control programmes for Strongyloides stercoralis infection is among the targets of the World Health Organization Roadmap to 2030. Aim of this work was to evaluate the possible impact in terms of economic resources and health status of two different strategies of preventive chemotherapy (PC) compared to the current situation (strategy A, no PC): administration of ivermectin to school-age children (SAC) and adults (strategy B) versus ivermectin to SAC only (strategy C). Methods The study was conducted at the IRCCS Sacro Cuore Don Calabria hospital, Negrar di Valpolicella, Verona, Italy, at the University of Florence, Italy, and at the WHO, Geneva, Switzerland, from May 2020 to April 2021. Data for the model were extracted from literature. A mathematical model was developed in Microsoft Excel to assess the impact of strategies B and C in a standard population of 1 million subjects living in a strongyloidiasis endemic area. In a case base scenario, 15% prevalence of strongyloidiasis was considered; the 3 strategies were then evaluated at different thresholds of prevalence, ranging from 5 to 20%. The results were reported as number of infected subjects, deaths, costs, and Incremental-Effectiveness Ratio (ICER). A 1-year and a 10-year horizons were considered. Results In the case base scenario, cases of infections would reduce dramatically in the first year of implementation of PC with both strategy B and C: from 172 500 cases to 77 040 following strategy B and 146 700 following strategy C. The additional cost per recovered person was United States Dollar (USD) 2.83 and USD 1.13 in strategy B and C, respectively, compared to no treatment in the first year. For both strategies, there was a downtrend in costs per recovered person with increasing prevalence. The number of adverted deaths was larger for strategy B than C, but cost to advert one death was lower for strategy C than B. Conclusions This analysis permits to estimate the impact of two PC strategies for the control of strongyloidiasis in terms of costs and adverted infections/deaths. This could represent a basis on which each endemic country can evaluate which strategy can be implemented, based on available funds and national health priorities.

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Prevalence and intensity of Schistosoma mansoni and hookworm infections among pre-school and school-aged children in Ilemela District, north-western Tanzania

Tanzania Journal of Health Research ◽

10.4314/thrb.v18i2.7 ◽

2016 ◽

Vol 18 (2) ◽

Author(s):

Samuel D. Ndokeji ◽

Humphrey D. Mazigo ◽

Mansuet Temu ◽

Coleman Kishamawe ◽

Wabyahe Malenganisho ◽

...

Keyword(s):

Schistosoma Mansoni ◽

School Children ◽

Age Groups ◽

Cross Sectional Study ◽

World Health ◽

School Age Children ◽

Hookworm Infection ◽

Cross Sectional ◽

Hookworm Infections ◽

North Western

Background: World Health Organization have recently recommended the inclusion of pre-school children in the Mass Drug Administration (MDA) against schistosomiasis and soil-transmitted helminths in endemic areas. This study was conducted to determine the prevalence and intensity of Schistosoma mansoni and hookworm infections among pre- and school going children in Ilemela District, north-western Tanzania.Methods: This cross-sectional study included pre- and school going children aged 4-14 years. A single stool sample was collected from each child and processed using Kato Katz thick smears and examined microscopically for presence of S. mansoni and hookworm eggs. A questionnaire was used to collect demographic information of the study participants.Results: Overall, prevalence of S. mansoni was 80.0%; with pre-school children aged 4-6 years having the point prevalence of 60.6%. The overall prevalence of hookworm infection was 18.7%; with age group 4-6 years having the prevalence of 14.1%. The intensity of hookworm infection was light in all age groups. The intensity of infection of S. mansoni increased with age. Using lake water for domestic purposes (OR=3.09, 95% CI: 1.93-4.95, p<0.001), for bathing (OR=2.65, 95% CI: 1.66-4.23, p<0.0001), and for washing purposes (OR=3.08, 95% CI: 1.90-4.97, p<0.0001) remained independently associated with S. mansoni infection. Children who reported to swim in the lake and involved in paddy farming had 1.84 and 1.95 times odds of being infected than those who did not, respectively.Conclusion: These findings indicate that S. mansoni and hookworm infections are common among pre-school children as well as in school going children. These findings call for the need to urgently include the pre-school age children the MDSA programme.

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Prevalence of Soil-transmitted Helminth Infections Among School-age Children in Ethiopia: a Systematic Review and Meta-analysis

10.21203/rs.3.rs-1014995/v1 ◽

2021 ◽

Author(s):

Muluken Azage ◽

Achenef Motbainor ◽

Genet Gedamu ◽

Wendemagegne Enbiale

Keyword(s):

Systematic Review ◽

Control Strategies ◽

Data Extraction ◽

Meta Analysis ◽

Control Measures ◽

School Age Children ◽

Cochrane Library ◽

School Age ◽

Preventive Chemotherapy ◽

Pooled Prevalence

Abstract Background: In Ethiopia, soil-transmitted helminthiasis (STHs) infections remain the leading cause of morbidity among school-age children despite the progress in the implementation of control measures. Study findings regarding prevalence of STH among school-age children have been inconsistent and pooled prevalence of STH infections did not account double or triple infections of STH. Therefore, this systematic review and meta-analysis estimates the pooled prevalence of STH by accounting double or triple infections among school-age children in Ethiopia.Methods: Databases and search engines such as PubMed, Web of Science, EMBASE, CINAHL, Google Scholar, Science Direct, and the Cochrane Library were systematically searched. Based on the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was employed to determine the prevalence of STH infections among school-age children. Published articles in the period between 1980 and 2020 were included in the analysis. Three authors independently extracted all data using a data extraction format sheet. STATA Version 16 statistical software was used for analysis. The Cochran’s Q-test was used to evaluate the heterogeneity of the studies and a random-effects model was done to determine pooled prevalence estimate.Results: The overall pooled estimate of STHs was 33% (95% CI:26-39%). The prevalence did not show statistically differ between before, 32.0% (95% CI:25-39%) and after, 33% (95% CI:26-39%) National NTDs control and elimination programme. The pooled prevalence of ascariasis before and after the implementation of NTDs programme was found to be 18% (12.0%, 24%) and 18% (9.0%, 27.0%), respectively with a total pooled estimate of 18.0% (13.0%, 23.0%). The prevalence of trichuris trichuria was also found to be 8.0% (4.0%, 12.0%) before the programme and 15.0% (4%, 26%) after the programme with a total pooled estimate of 10.0% (5.0%, 14.0%). The prevalence of hookworm was 14.0% (9.0%, 19.0%) before the programme and 9.0% (3.0%, 14.0%) after the programme with a total pooled estimate of 12% (8.0%, 17.0%). Conclusion: The overall polled prevalence of STHs in Ethiopia was found at moderate level based on the WHO classification. The recommended control strategies for STHs infections in school-age children at this level of prevalence such as providing preventive chemotherapy or treat all school-age children (enrolled and non-enrolled) once a year, improving sanitation and water supply and providing health education should be strengthen to mee the target of the national and WHO plan.

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A systematic review and meta-analysis quantifying schistosomiasis infection burden in pre-school aged children (PreSAC) in sub-Saharan Africa for the period 2000–2020

PLoS ONE ◽

10.1371/journal.pone.0244695 ◽

2020 ◽

Vol 15 (12) ◽

pp. e0244695

Author(s):

Chester Kalinda ◽

Tafadzwa Mindu ◽

Moses John Chimbari

Keyword(s):

Systematic Review ◽

Publication Bias ◽

Quantitative Data ◽

Sub Saharan Africa ◽

World Health ◽

Infection Prevalence ◽

School Aged Children ◽

Control Programmes ◽

Sub Saharan ◽

Preschool Aged Children

Introduction Following the adoption of the World Health Assembly Resolution WHA 65.21 and Neglected Tropical Diseases road map 2021–2030, schistosomiasis control programmes have shifted from morbidity control to disease elimination. However, several gaps continue to be observed in the implementation of control programmes with certain age groups omitted from these campaigns increasing health inequalities and risks of reinfections to previously treated groups. We used the Inverse Variance Heterogeneity (IVhet) model to estimate the prevalence of schistosomiasis infection among preschool-aged children. Methods We did a systematic review of peer-reviewed literature on schistosomiasis in sub-Saharan Africa for the period January 1, 2000 to November 30, 2020. Quantitative data for cases of schistosomiasis infection were extracted, including country and region where the studies were done, year of publication and specific schistosome species observed. The IVhet model was used to estimate the pooled prevalence estimate (PPE), the heterogeneity and publication bias. Results We screened 2601 articles to obtain 47 eligible studies containing quantitative data on preschool-aged children. Of the selected studies, 44.7% (n = 22) were from East Africa while the least number of studies obtained (2.1%, n = 1) was from Central Africa. 21712 subjects were screened for infection due to Schistosoma spp; 13924 for S. mansoni and 7788 for S. haematobium. The PPE for schistosomiasis among PreSAC was 19% (95% CI: 11–28). Infection due to S. mansoni (IVhet PPE: 22% (95% CI: 9–36) was higher than that due to S. haematobium (15%; 95% CI: 6–25). A Luis Furuya–Kanamori index of 1.83 indicated a lack of publication bias. High level of heterogeneity was observed (I2 > 90%) and this could not be reduced through subgroup analysis. Conclusion Schistosomiasis infection among pre-school aged children 6 years old and below is high. This indicates the importance of including this age group in treatment programmes to reduce infection prevalence and long-term morbidities associated with prolonged schistosome infection.

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Modelling the impact of COVID-19-related control programme interruptions on progress towards the WHO 2030 target for soil-transmitted helminths

10.1101/2020.11.01.20220376 ◽

2020 ◽

Author(s):

Veronica Malizia ◽

Federica Giardina ◽

Carolin Vegvari ◽

Sumali Bajaj ◽

Kevin McRae-McKee ◽

...

Keyword(s):

Control Programme ◽

Mitigation Strategies ◽

World Health ◽

Preventive Chemotherapy ◽

Soil Transmitted Helminths ◽

Individual Based Models ◽

Control Programmes ◽

Catch Up ◽

Health Organization ◽

The Impact

AbstractBackgroundOn the 1st of April 2020, the World Health Organization (WHO) recommended an interruption of all neglected tropical disease control programmes, including soil-transmitted helminths (STH), in response to the COVID-19 pandemic. This paper investigates the impact of this disruption on the achieved progress towards the WHO 2030 target for STH.MethodsWe used two stochastic individual-based models to simulate the impact of missing one or more preventive chemotherapy (PC) rounds in different endemicity settings. We also investigate the extent to which the impact can be lessened by mitigation strategies, such as semi-annual or community-wide PC.ResultsBoth models show that even without a mitigation strategy, control programmes will catch up by 2030. The catch-up time is limited to a maximum of 4.5 years after the interruption. Mitigations strategies may reduce this catch-up time by up to two years and can even increase the probability of achieving the 2030 target.ConclusionsThough a PC interruption will only temporarily impact the progress towards the WHO 2030 target, programmes are encouraged to restart as soon as possible to minimise the impact on morbidity. The implementation of suitable mitigation strategies can turn the interruption into an opportunity to accelerate the progress toward reaching the target.

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