Shaali Makame Ame

Background: In East Africa, bovine schistosomiasis, although common, is poorly appreciated and managed, detrimentally impacting upon livestock health. In certain settings, bovine schistosomiasis may be involved in zoonotic transmission of human schistosomiasis. Better disease management and more effective control of bovine schistosomiasis require the development of sensitive and specific serological screening and rapid diagnostic tools. Methods: We developed an enzyme-linked immunosorbent assay (ELISA) for Schistosoma bovis detection in cattle, utilizing nine shortlisted potential diagnostic protein targets. These shortlisted candidates, STI, IPP, OP, PGK1, COG, PDZ, and Sbp80 (as three fragments), were identified from Schistosoma japonicum homologs already reported with the highest diagnostic potential. In S. bovis, these proteins participate in various biological processes, including metabolic pathways, transcriptional regulation, glycolysis, phosphorylation, and cell signalling, although their real diagnostic potential has not been explored until now. Results: The ELISA was optimized using bovine blood serum samples from regions in Tanzania and validated for sensitivity and specificity. Two targets of specific focus, Conserved Oligomerix Golgi complex subunit 4 (COG) and a domain of the cysteine protease calpain (Sbp80), achieved the highest specificity and sensitivity among the recombinant proteins, with 92% and 88% sensitivity and 100% and 80% specificity, respectively. We further evaluated the COG-based and calpain-based ELISA on further “real-world” bovine serum samples from abattoir sites in Zanzibar, detecting S. bovis in 59.1% of tested animals. Conclusions: Both COG and calpain are promising candidates for serological screening and later inclusion in portable diagnostic tests for S. bovis infection in cattle. Such future diagnostic assays will enable better point-of-detection monitoring, and once scalable, aid in the control of disease in cattle. Graphical

The transfer of antimicrobial resistance genes (ARGs) from environmental microbes to pathogens is a critical but underexplored One Health driver of antimicrobial resistance. Here, we evaluate freshwater snails, which are geographically widespread aquatic invertebrates, as environmental reservoirs of ARGs. We collected faeces from eight gastropod genera at 15 freshwater locations across Malawi, Uganda, Zanzibar and the UK and conducted the first freshwater snail faecal metagenomic study. We detected putative ARGs predicted to confer resistance to 13 antibiotic classes, including carbapenems. All ARGs that could be assembled into metagenome-assembled genomes (MAGs) were found within Proteobacteria, which dominated the faecal microbiomes and were strongly associated with the total ARG load. In Malawi, we linked bla OXA-181 (bla OXA-48-like), a previously mobilized carbapenemase gene, to Shewanella xiamenensis, the gene’s known progenitor. We detected another bla OXA-48-like gene by read mapping from a sample in the UK. We identified mobile colistin resistance (mcr)-like genes at 11 of 15 locations, with two mcr-7-like genes being found in an Aeromonas jandaei MAG in Uganda. Our findings highlight freshwater snail faeces as a One Health-relevant environmental reservoir of clinically important ARGs.

Background Lymphatic filariasis (LF) is a debilitating neglected tropical disease which is targeted for elimination through co-administration of a single dose of ivermectin and albendazole in the affected population. Following implementation of such a treatment campaign over a period of years, control programmes are urged to conduct a transmission assessment survey to monitor the impact of the treatment and to ascertain whether the transmission is interrupted to a level that can no longer sustain transmission and hence mass drug administration (MDA) can be halted. Objective:This study was carried out to determine the prevalence of LF infection in Zanzibar communities, 13 years after stopping MDA, so as to inform and guide the control program. MethodologyA Finger prick blood sample was collected from each participant after obtaining informed consent. The sample was assessed for the presence of Wucheria bancrofti circulating antigen using rapid immunochromatographic test. ResultsA total of 2555 subjects were enrolled (1231 in Pemba and 1324 in Unguja) in the study with a mean age of 23.0yrs ± SD 18.9 (95% CI = 22.3-23.8). There were more female (53.9%) than male (46.1%); and their mean age significantly differed (t-test = 7.5, p = 0.00001). Only 2478 individuals gave blood sample . Of these, 88 (3.55%) were found to be infected with W. bancrofti. Overall, the prevalence of infection was higher in Pemba (5.1%) than in Unguja (2.1%). The prevalence of infection was similar between different older age groups , children aged 1-5yrs in Pemba had the highest prevalence indicating that transmission is ongoing. Observation of development of clinical manifestation, lymphoedema and hydrocele was also assessed. Overall, only 1.1% of the individuals had lymphoedema/elephantiasis; with male presented with more of those signs (1.6%) than female (0.7%). There was no male subject found to have hydrocele , although 8.3% of male had filariasis.The assessment of treatment history revealed that majority (64.7%) of the respondents had received at least one treatment round during their lifetime. Historical treatments with ivermectin did not correlate with current individual levels of infection but individuals who reported to have received 2 and 4 rounds of treatment were not found to be infected with filariasis.Conclusion and RecommendationIn view of our findings it clearly shows that the prevalence of LF in Zanzibar is still high to exceed the set threshold for discontinuation of MDA campaign. Children as young as 5yrs were found infected. It is therefore important to consider continuation of MDA so as to prevent potential disease sequel which might develop.

Accurate diagnosis of urogenital schistosomiasis is crucial for disease surveillance and control. Routine diagnostic methods, however, lack sensitivity when assessing patients with low levels of infection still able to maintain pathogen transmission. Therefore, there is a need for highly sensitive diagnostic tools that can be used at the point-of-care in endemic areas. Recombinase polymerase amplification (RPA) is a rapid and sensitive diagnostic tool that has been used to diagnose several pathogens at the point-of-care. Here, the analytical performance of a previously developed RPA assay (RT-ShDra1-RPA) targeting the Schistosoma haematobium Dra1 genomic region was assessed using commercially synthesised S. haematobium Dra1 copies and laboratory-prepared samples spiked with S. haematobium eggs. Clinical performance was also assessed by comparing diagnostic outcomes with that of a reference diagnostic standard, urine-egg microscopy. The RT-ShDra1-RPA was able to detect 1 × 10¹ copies of commercially synthesised Dra1 DNA as well as one S. haematobium egg within laboratory-spiked ddH₂O samples. When compared with urine-egg microscopy, the overall sensitivity and specificity of the RT-ShDra1-RPA assay was 93.7% (±88.7–96.9) and 100% (±69.1–100), respectively. Positive and negative predictive values were 100% (±97.5–100) and 50% (±27.2–72.8), respectively. The RT-ShDra1-RPA therefore shows promise as a rapid and highly sensitive diagnostic tool able to diagnose urogenital schistosomiasis at the point-of-care.

Background: Efforts to control and eliminate schistosomiasis have accelerated over the past decade. As parasite burden, associated morbidity and egg excretion decrease, diagnosis with standard parasitological methods becomes harder. We assessed the robustness and performance of a real-time PCR (qPCR) approach in comparison with urine filtration microscopy and reagent strip testing for the diagnosis of Schistosoma haematobium infections of different intensities. Methods: The robustness of DNA isolation and qPCR was validated in eight laboratories from Europe and Africa. Subsequently, 792 urine samples collected during cross-sectional surveys of the Zanzibar Elimination of Schistosomiasis Transmission (ZEST) project in 2012–2017 were examined with qPCR in 2018. Diagnostic sensitivity of the qPCR was calculated at different infection intensity categories, using urine filtration microscopy as reference test. Spearman’s rank correlation between Ct-values and S. haematobium egg counts was assessed and Ct-value percentiles for infection intensity categories determined. Results: S. haematobium Dra1 DNA-positive samples were identified correctly in all eight laboratories. Examination of urine samples from Zanzibar revealed Dra1 DNA in 26.8% (212/792) by qPCR, S. haematobium eggs in 13.3% (105/792) by urine filtration, and microhaematuria in 13.8% (109/792) by reagent strips. Sensitivity of the qPCR increased with augmenting egg counts: 80.6% (29/36) for counts between 1 and 4 eggs, 83.3% (15/18) for counts between 5 and 9 eggs, 100% (23/23) for counts between 10 and 49 eggs, and 96.4% (27/28) for counts of 50+ eggs. There was a significant negative correlation between Ct-values and egg counts (Spearman’s rho = − 0.49, P < 0.001). Seventy-five percent of the Ct-values were ≥ 33 in the egg-negative category, < 31 in the light intensity category, and < 24 in the heavy intensity category. Conclusions: While the sensitivity of the qPCR was ~ 80% for very light intensity infections (egg counts < 10), in general, the Dra1 based qPCR assay detected twice as many S. haematobium infections compared with classical parasitological tests. The qPCR is hence a sensitive, urine-based approach for S. haematobium diagnosis that can be used for impact assessment of schistosomiasis elimination programmes, individual diagnosis, and in improved format also for verification and certification of elimination. Trial registration: ISRCTN, ISRCTN48837681. Registered 05 September 2012 - Retrospectively registered.

Schistosomiasis, a neglected tropical disease of medical and veterinary importance, transmitted through specific freshwater snail intermediate hosts, is targeted for elimination in several endemic regions in sub-Saharan Africa. Multi-disciplinary methods are required for both human and environmental diagnostics to certify schistosomiasis elimination when eventually reached. Molecular xenomonitoring protocols, a DNA-based detection method for screening disease vectors, have been developed and trialed for parasites transmitted by hematophagous insects, such as filarial worms and trypanosomes, yet few have been extensively trialed or proven reliable for the intermediate host snails transmitting schistosomes. Here, previously published universal and Schistosoma-specific internal transcribed spacer (ITS) rDNA primers were adapted into a triplex PCR primer assay that allowed for simple, robust, and rapid detection of Schistosoma haematobium and Schistosoma bovis in Bulinus snails. We showed this two-step protocol could sensitively detect DNA of a single larval schistosome from experimentally infected snails and demonstrate its functionality for detecting S. haematobium infections in wild-caught snails from Zanzibar. Such surveillance tools are a necessity for succeeding in and certifying the 2030 control and elimination goals set by the World Health Organization.

The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was created in 2008 to answer questions of importance to program managers working to reduce the burden of schistosomiasis in Africa. In the past, intermediate host snail monitoring and control was an important part of integrated schistosomiasis control. However, in Africa, efforts to control snails have declined dramatically over the last 30 years. A resurgence of interest in the control of snails has been prompted by the realization, backed by a World Health Assembly resolution (WHA65.21), that mass drug administration alone may be insufficient to achieve schistosomiasis elimination. SCORE has supported work on snail identification and mapping and investigated how xenomonitoring techniques can aid in the identification of infected snails and thereby identify potential transmission areas. Focal mollusciciding with niclosamide was undertaken in Zanzibar and Côte d’Ivoire as a part of elimination studies. Two studies involving biological control of snails were conducted: one explored the association of freshwater riverine prawns and snail hosts in Côte d’Ivoire and the other assessed the current distribution of Procambarus clarkii, the invasive Louisiana red swamp crayfish, in Kenya and its association with snail hosts and schistosomiasis transmission. SCORE also supported modeling studies on the importance of snail control in achieving elimination and a meta-analysis of the impact of molluscicide-based snail control programs on human schistosomiasis prevalence and incidence. SCORE’s snail control studies contributed to increased investment in building capacity, and specimens collected during SCORE research deposited in the Schistosomiasis Collections at the Natural History Museum (SCAN) will provide a valuable resource for the years to come.

As part of its diverse portfolio, the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) included two cluster-randomized trials evaluating interventions that could potentially lead to interruption of schistosomiasis transmission (elimination) in areas of Africa with low prevalence and intensity of infection. These studies, conducted in Zanzibar and Cote d'Ivoire, demonstrated that multiyear mass drug administration (MDA) with praziquantel failed to interrupt the transmission of urogenital schistosomiasis, even when provided biannually and/or supplemented by small-scale implementation of additional interventions. Other SCORE activities related to elimination included a feasibility and acceptability assessment of test-treat-track-test-treat (T5) strategies and mathematical modeling. Future evaluations of interventions to eliminate schistosomiasis should recognize the difficulties inherent in conducting randomized controlled trials on elimination and in measuring small changes where baseline prevalence is low. Highly sensitive and specific diagnostic tests for use in very low-prevalence areas for schistosomiasis are not routinely available, which complicates accurate measurement of infection rates and assessment of changes resulting from interventions in these settings. Although not encountered in these two studies, as prevalence and intensity decrease, political and community commitment to population-wide MDA may decrease. Because of this potential problem, SCORE developed and funded the T5 strategy implemented in Egypt, Kenya, and Tanzania. It is likely that focal MDA campaigns, along with more targeted approaches, including a T5 strategy and snail control, will need to be supplemented with the provision of clean water and sanitation and behavior change communications to achieve interruption of schistosome transmission.

Background: In clinical research, obtaining informed consent from participants is an ethical and legal requirement. Conveying the information concerning the study can be done using multiple methods yet this step commonly relies exclusively on the informed consent form alone. While this is legal, it does not ensure the participant’s true comprehension. New effective methods of conveying consent information should be tested. In this study we compared the effect of different methods on the knowledge of caregivers of participants of a clinical trial on Pemba Island, Tanzania.Methods: A total of 254 caregivers were assigned to receive (i) a pamphlet (n = 63), (ii) an oral information session (n = 62) or (iii) a pamphlet and an oral information session (n = 64) about the clinical trial procedures, their rights, benefits and potential risks. Their post-intervention knowledge was assessed using a questionnaire. One group of caregivers had not received any information when they were interviewed (n = 65).Results: In contrast to the pamphlet, attending an information session significantly increased caregivers’ knowledge for some of the questions. Most of these questions were either related to the parasite (hookworm) or to the trial design (study procedures).Conclusions: In conclusion, within our trial on Pemba Island, a pamphlet was found to not be a good form of conveying clinical trial information while an oral information session improved knowledge. Not all caregivers attending an information session responded correctly to all questions; therefore, better forms of communicating information need to be found to achieve a truly informed consent.

Soil-transmitted helminthiasis affects almost 2 billion people worldwide in tropical climates. Preventive chemotherapy, using the benzimidazoles (albendazole and mebendazole) is the current main recommended control strategy. Nevertheless, there is limited efficacy of these drugs against hookworm infection and, to a greater extent, against trichuriasis. We describe a protocol for a trial investigating the efficacy and safety of the co-administration of ivermectin and albendazole against trichuriasis. A double-blind, placebo-controlled randomized controlled trial will be conducted in three countries (Côte d’Ivoire, Tanzania and Lao PDR) with the aim to determine the efficacy, safety and extended effects of co-administered ivermectin and albendazole compared to standard albendazole monotherapy. We will enroll 600 participants aged 6–60 years in each setting. The primary outcome is cure rate (CR) against Trichuris trichiura infection as assessed by Kato-Katz 14–21 days after treatment. Secondary outcomes include CRs against concomitant soil-transmitted helminth (STH) infections (Ascaris lumbricoides, hookworm and Strongyloides stercoralis) and egg reduction rates (ERRs) against STH at 14–21 days, 180 days and 360 days. Tolerability of treatment, infection status assessed by polymerase chain reaction (PCR), and potential benefits of deworming on nutritional and morbidity indicators will be assessed. The primary analysis will include an available-case set and use logistic regression models adjusted for age, sex and weight. This trial will provide robust results on the efficacy and safety of co-administration of ivermectin and albendazole with the aim to better inform WHO recommendations on control of STHs. Furthermore, secondary and explanatory outcomes will provide direct evidence on the extended effects of combination therapy and insight on the relationship between nutrition and morbidity parameters and infection status and intensity. NCT03527732 (date assigned: 17 May 2018).