Bacteriome Diversity of Blackflies’ Gut and Association with Onchocerca volvulus, the Causative Agent of Onchocerciasis in Mbam Valley (Center Region, Cameroon)

Vector control using larvicides is the main alternative strategy to address limits of preventive chemotherapy using ivermectin for the control of onchocerciasis. However, it remains substantially limited by implementation difficulties, ecological concerns and the resistance of vector populations. Therefore, efficient and environmentally safe alternative control strategies are still needed. This study explores the composition of the blackfly bacteriome and its variability in the presence of Onchocerca volvulus infection, in order to determine their potential as a novel vector control-based approach to fight onchocerciasis. An entomological survey of a collection of samples was performed in the Bafia health district, a historical endemic focus for onchocerciasis in Cameroon. A total of 1270 blackflies were dissected and the infection rate was 10.1%, indicative of ongoing transmission of onchocerciasis in the surveyed communities. Sequencing process of blackflies’ gut DNA for bacteria screening revealed 14 phyla and 123 genera, highlighting the diversity of gut blackflies bacterial communities. Eight bacteria formed the core of blackfly bacteriome and Wolbachia was the predominant genus with 73.4% of relative abundance of blackflies’ gut bacterial communities. Acidomonas and Roseanomas genera were significantly abundant among infected blackflies (p = 0.01), whereas other genera such as Brevibacterium and Fructobacillus were associated with the absence of infection (p = 0.0009). Differences in gut bacterial distribution of blackflies according to their infection status by the parasite suggest a causal relationship between the bacteriome composition and the onset of blackflies’ infection by O. volvulus or vice versa. Blackfly native bacteria are then potentially involved in infection by O. volvulus, either by facilitating or preventing the parasite infestation of the vector. These bacteria represent an interesting potential as a biological tool/target for a novel approach of vector control to fight onchocerciasis.

Coverage evaluation surveys following soil-transmitted helminthiasis and schistosomiasis mass drug administration in Wolaita Zone of Ethiopia—The Geshiyaro project

Introduction The Geshiyaro project aims to break transmission of soil-transmitted helminths and schistosomiasis in the Wolaita Zone of Ethiopia through a combination of two interventions: behavior change communication (BCC) for increased water, sanitation and hygiene (WaSH) infrastructure use alongside preventive chemotherapy (PC) using albendazole (ALB) and praziquantel (PZQ), targeted to reach 90% treatment coverage. Coverage evaluation surveys (CES) were conducted post-treatment, and the resultant survey coverage was compared to reported administrative coverage. This provided a secondary confirmation of the Geshiyaro project coverages, and is used to monitor the success of each Mass Drug Administration (MDA) round. Methods A community-based cross-sectional study was conducted in 13 woredas (districts) of the Wolaita Zone. All eligible individuals from the selected households were invited for an interview. The study design, sample size, analysis and report writing were conducted according to the World Health Organization (WHO) CES guidelines for PC. Results The study interviewed a total of 3,568 households and 18,875 individuals across 13 woredas in the Wolaita Zone. Overall, the survey coverage across all studied woredas was 81.5% (95% CI; 80.9–82.0%) for both ALB and PZQ. Reported administrative coverage across all studied woredas was higher than survey coverage, 92.7% and 91.2% for ALB and PZQ, respectively. A significant portion of individuals (17.6%) were not offered PC. The predominant reason for not achieving the target coverage of 90% was beneficiary absenteeism during MDA (6.6% ALB, 6.8% PZQ), followed by drug distributors failing to reach all households (4.7% ALB, 4.8% PZQ), and beneficiaries not informed of the program (1.3% ALB, 1.7% PZQ). Conclusion Programmatic actions will need to be taken during the next MDA campaign to achieve the targeted Geshiyaro project coverage threshold across data collection and program engagement. Adequate training and supervision on recording and reporting administrative coverage should be provided, alongside improved social mobilization of treated communities to increase participation, and strengthened institutional partnerships and communication.

Prevalence of soil-transmitted helminth infections, schistosomiasis, and lymphatic filariasis before and after preventive chemotherapy initiation in the Philippines: A systematic review and meta-analysis

Objective To estimate the impact of preventive chemotherapy on the prevalence and intensity of soil-transmitted helminth (STH) infections, schistosomiasis, and lymphatic filariasis in the Philippines, using systematic review and meta-analysis. Methods We included reports reporting prevalence of STH infections, schistosomiasis, or lymphatic filariasis in the Philippines published until 31 March 2021. Peer-reviewed studies were identified in electronic databases. Grey literature reports by the University of the Philippines and the Department of Health were also included. Pooled infection prevalence, before and after the initiation of preventive chemotherapy, stratified by age group, was calculated using the inverse variance heterogeneity model. Findings A total of 109 reports were included in the review and meta-analysis. Overall prevalence of moderate-heavy intensity Ascaris lumbricoides (6.6%) and Trichuris trichiura (2.7%) infection after initiation of preventive chemotherapy were significantly lower than the prevalence prior to initiation (23.6% for A. lumbricoides and 12.2% for T. trichiura). Prevalence reductions were also found in school and preschool-age children for A. lumbricoides and T. trichiura. Studies conducted after preventive chemotherapy initiation had significantly lower overall prevalence of moderate-heavy intensity schistosomiasis (3.1% vs 0.2%) and of schistosomiasis in school-age children (30.5% vs 1%). Pooled prevalence of lymphatic filariasis prior to preventive chemotherapy initiation was 3.2% across 12 provinces, while currently only two provinces still have prevalence of more than 1%. There were no published studies reporting prevalence of lymphatic filariasis after initiation of preventive chemotherapy. Heterogeneity was high with I2 mostly above 90%. Conclusion The burden of STH infections and schistosomiasis in children were significantly lower in studies conducted following the initiation of preventive chemotherapy. Eliminating morbidity and interrupting transmission, however, may require expanded control initiatives including community-wide treatment, and improved water, sanitation, and hygiene. Lymphatic filariasis burden has decreased since the implementation of preventive chemotherapy, with all but two provinces having reached the elimination of lymphatic filariasis as a public health problem.

Treatment of Pregnant Women with Ivermectin during Mass Drug Distribution: Time to Investigate Its Safety and Potential Benefits

To date, pregnant women are excluded from programmes delivering community-directed treatment of ivermectin (CDTI) for onchocerciasis and preventive chemotherapy of other helminthiases because of concerns over ivermectin safety during pregnancy. This systematic exclusion sustains an infection reservoir at the community level and deprives a vulnerable population from known benefits—there are indications that treating O. volvulus infected women may improve pregnancy outcomes and reduce the risk that their children develop onchocerciasis-associated morbidities. Furthermore, teratogenic effects are seen in non-clinical experiments at doses that far exceed those used in CDTI. Lastly, early, undetected and undeclared pregnancies are being systematically exposed to ivermectin in practice. Treatment of this population requires appropriate supporting evidence, for which we propose a three-pronged approach. First, to develop a roadmap defining the key steps needed to obtain regulatory clearance for the safe and effective use of ivermectin in all pregnant women who need it. Second, to conduct a randomised placebo-controlled double-blind clinical trial to evaluate the safety and benefits of ivermectin treatment in O. volvulus infected pregnant women. Such a trial should evaluate the possible effects of ivermectin in reducing adverse pregnancy outcomes and neonatal mortality, as well as in reducing the incidence of onchocerciasis-associated epilepsy. Third, to establish a pregnancy registry for women who inadvertently received ivermectin during pregnancy. This situation is not unique to ivermectin. Access to valuable therapies is often limited, delayed, or denied to pregnant women due to a lack of evidence. Concerns over protecting vulnerable people may result in harming them. We need to find acceptable ways to build robust evidence towards providing essential interventions during pregnancy.

Development of a public geographical information system-based website to follow the impact of control activities of soil-transmitted helminths in endemic countries

Soil-transmitted helminth (STH) infections are among the most common neglected tropical diseases worldwide causing high morbidity and mortality rates in endemic areas. Preventive chemotherapy (PC) programmes and health education are recommended by the World Health Organization (WHO) to reduce the impact of STH in endemic countries. Following our role as WHO collaborating centre (WHO CC ITA-116), we have developed a WebGIS and a dataset to support PC programmes to monitor the impact of STH control. This vHealth presentation shows the potentiality of these tools in improving communication among WHO’s regional and country offices, Ministries of Health, pharmaceutical industries and other partners.

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

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.

Factors influencing mass drug administration adherence and community drug distributor opportunity costs in Liberia: a mixed-methods approach

Background Preventive chemotherapy delivered via mass drug administration (MDA) is essential for the control of neglected tropical diseases (NTDs), including lymphatic filariasis (LF), schistosomiasis and onchocerciasis. Successful MDA relies heavily on community drug distributor (CDD) volunteers as the interface between households and the health system. This study sought to document and analyse demand-side (households) and supply-side (health system) factors that affect MDA delivery in Liberia. Methods Working in two purposively selected counties, we conducted a household MDA access and adherence survey; a CDD survey to obtain information on direct and opportunity costs associated with MDA work; an observational survey of CDDs; and key informant surveys (KIS) with community-level health workers. Data from the CDD survey and Liberian minimum wage rates were used to calculate the opportunity cost of CDD participation per MDA round. The observational data were used to calculate the time spent on individual household-level tasks and CDD time costs per house visited. KIS data on the organisation and management of the MDA in the communities, and researcher reflections of open-ended survey responses were thematically analysed to identify key demand- and supply-side challenges. Results More respondents were aware of MDA than NTD in both counties. In Bong, 39% (103/261) of respondents reported taking the MDA tablet in the last round, with “not being informed” as the most important reason for non-adherence. In Maryland, 56% (147/263) reported taking MDA with “being absent” at the time of distribution being important for non-adherence. The mean cost per CDD of participating in the MDA round was −$11.90 (median $5.04, range −$169.62 to $30.00), and the mean time per household visited was 17.14 min which equates to a mean opportunity cost of $0.03 to $0.05 per household visited. Thematic analysis identified challenges, including shortages of and delays in medicine availability; CDD frustration over costs; reporting challenges; and household concerns about drug side effects. Conclusions Improved adherence to MDA and subsequent elimination of NTDs in Liberia would be supported by an improved medicine supply chain, financial compensation for CDDs, improved training, healthcare workforce strengthening, greater community involvement, capacity building, and community awareness. Graphical Abstract

An Integrated Approach to Assess Knowledge/Perceptions and Attitudes/Practices (KAP) Regarding Major Neglected Tropical Diseases Endemic in the Mbengwi Health District, North West Region, Cameroon

Background and objectives Preventive chemotherapy (PCT) is the main strategy currently used to control and/or eliminate onchocerciasis, lymphatic filariasis (LF) and soil transmitted helminthiasis (STH), and community participation (through implementation or adherence to PCT) is critical. This study aimed at investigating knowledge/perceptions of populations of the Mbengwi health district (North West Region, Cameroon), in relation to their attitudes/practices regarding the most prevalent neglected tropical diseases (NTDs). Methods A household-based cross-sectional survey was carried out in the Mbengwi health district (North West Region, Cameroon) using the cluster sampling technique. Clusters were selected using the probability proportionate to estimate size strategy. In each cluster, the random walk technique was used for the selection of households, and a structure questionnaire was administered to 2–3 of its members. Results A total of 254 households from 26 clusters were visited, and 514 individuals were interviewed. The sex ratio of interviewees (1.08) was unbiased, and their ages ranged between 10 and 99 years old. Though most of the respondents declared having already heard of these NTDs (41.6%, 73.9% and 90.5% for onchocerciasis, LF and STH, respectively), only a minority of them were aware of how they are acquired/transmitted (8.9%, 9.2% and 32.7% for onchocerciasis, LF and STH, respectively), or prevented (23.1%, 18.9% and 47.2% for onchocerciasis, LF and STH, respectively). Conclusions This study revealed poor knowledge/perceptions and wrong attitudes/practices of interviewees as regards to these NTDs, and these misconceptions can seriously affect the adherence and contribution of populations to the success of PCTs. It appears compulsory to reinforce information, education, and communication, with a focus on the rationale and importance behind PCTs, to optimize/improve community participation.

Urinary Schistosomiasis and Primary Evidence of Female Genital Schistosomiasis among Pupils in Nsugbe Community, Anambra State, Nigeria

Urinary schistosomiasis is considered a major public health parasitic disease in African communities. Prior to this study, Nsugbe community was not considered endemic for the disease and as such was not involved in Praziquantel-Preventive Chemotherapy (PC). Longitudinal study of 281 consented pupils aged 5-16 years was carried out with aim of determining the status of urinary schistosomiasis. Urinalysis laboratory test strip, urine filtration technique and syndromic diagnosis were used for the confirmation of the presence of haematuria in urine samples, identification of Schistosoma haematobium ova and the confirmation of female genital schistosomiasis (FGS), respectively. Risk factors for urinary schistosomiasis infection were determined using pre-tested structured questionnaire. Data were analyzed using Minitab 17 software and intensity of infection categorized following World Health Organization (WHO) recommendations. Of the 281 pupils, 117 (42%) were males and 164 (58%) were females with mean age of 9 years. At baseline, an overall prevalence of 0.4% (1/281) which was of light intensity was established. At follow-up, an overall prevalence of 2.1% (6/281) which was of both light (16.7%) and heavy infection (83.3%) was established. The result of the clinical examination showed eggs of S. haematobium in and around the vaginal area indicating FGS of a female pupil aged 12 years. This was treated. Identified risk factors for S. haematobium infection in the community include water-contact activities, ignorance, source of water supply among others. The study revealed the need for an all inclusive mass administration of Praziquantel-PC in the study community for effective control and possible elimination.