Peter Makaula

While a causal link between urogenital schistosomiasis ( Schistosoma haematobium ) and anaemia is well established, quantitative associations between infection intensity and haemoglobin levels across endemic communities, at fine spatial scales, remain insufficiently characterized. As part of the broader Hybridisation in Urogenital Schistosomiasis (HUGS) investigation, we studied the micro-epidemiology of anaemia within two study communities in southern Malawi where S. haematobium remains endemic. Urine samples were examined by microscopy to quantify S. haematobium infection intensity, categorised as low (0–9 eggs/10 mL), moderate (10–49 eggs/10 mL), and heavy (≥50 eggs/10 mL). Individual haemoglobin concentrations were measured using a HemoCue photometer in 1,149 participants from Samama village (Mangochi District) and 977 participants from Mthawira village (Nsanje District). Linear geostatistical models incorporating individual-level characteristics and spatial covariates were used to estimate anaemia prevalence at fine geographical scales. Moderate anaemia (Hb 80–109 g/L) was most prevalent among children aged 6–12 years (45.30% in Samama and 39.54% in Mthawira), while severe anaemia was more frequent among adults aged ≥19 years in both villages. Increasing S. haematobium infection intensity was associated with lower haemoglobin levels, with individuals harbouring heavy infections being at greater risk of moderate-to-severe anaemia. Spatial modelling revealed longer-range spatial correlation in Nsanje (φ = 66.7 km) than in Mangochi (φ = 25.5 km), indicating more spatially persistent risk in Nsanje and more localized heterogeneity in Mangochi. Predicted anaemia prevalence among female children aged 6–12 years with moderate infection intensity ranged from 25–65% in Mangochi and 64–76% in Nsanje. At the micro-epidemiological level, S. haematobium infection intensity was associated with the severity of anaemia, with substantial spatial heterogeneity within and between villages. Identification of high-risk clusters supports targeted interventions, including stepped-up preventive chemotherapy, improved water and sanitation, and iron supplementation.

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 Intestinal schistosomiasis was confirmed endemic in Mangochi District, Malawi, in May of 2018 following an unexpected encounter with discreet populations of Biomphalaria spp. freshwater snails during routine malacological surveillance activities. Since then, only limited malacological surveillance of Biomphalaria has been carried out, and so the distribution of Biomphalaria populations in this area is currently unclear. Additionally, sites of active Schistosoma mansoni transmission in this area are also unknown. Here, through extensive malacological surveillance, we aimed to formally document the distribution of Biomphalaria in Mangochi District. We also aimed to identify active intestinal schistosomiasis transmission sites in this area through subjecting all collected Biomphalaria to a recently developed S. mansoni-specific molecular xenomonitoring PCR.Methods Three malacological surveys were carried out along the southern shoreline of Lake Malawi, Mangochi District, Malawi, in November 2021, July 2022 and October/November 2022. All collected Biomphalaria were subjected to cercarial shedding analysis to identify active Schistosoma infections. Shed cercariae were then genotyped to species level using a standard multi-locus PCR and Sanger sequencing protocol. Following this, a subset of Biomphalaria from each collection site were also genotyped to species level using a standard PCR and Sanger sequencing protocol. All collected Biomphalaria were then subjected to a recently developed S. mansoni-specific molecular xenomonitoring PCR to identify infected, but non-shedding, Biomphalaria. Results A total of 589 Biomphalaria were collected across all three surveys. One single Biomphalaria (0.17%) was found to be actively shedding Schistosoma cercariae, which were molecularly confirmed as S. mansoni. All genotyped Biomphalaria (n = 42) were molecularly identified as Bi. pfeifferi. A further 19 Biomphalaria, collected from four different surveillance sites, were found to be infected with S. mansoni through molecular xenomonitoring. Intestinal schistosomiasis transmission was therefore identified at four different foci in Mangochi District.Discussion Our study highlights the importance of molecular approaches to investigate Biomphalaria populations and monitor Biomphalaria associated intestinal schistosomiasis transmission in endemic areas. As such, the continued development and use of such approaches, in particular the development and use of molecular xenomonitoring assays that can be carried out in resource-poor schistosomiasis-endemic settings, is encouraged. The revision of ongoing schistosomiasis control programmes in Mangochi District, in line with World Health Organization recommendations, is also encouraged.

Background: Mass drug administration is one of the key interventions recommended by WHO to control certain NTDs. With most support from donors, health workers distribute antihelminthic drugs annually in Malawi. Mean community coverage of MDA from 2018 to 2020 was high at 87% for praziquantel and 82% for albendazole. However, once donor support diminishes sustaining these levels will be challenging. This study intended to compare the use of the community-directed intervention approach with the standard practice of using health workers in delivery of MDA campaigns. Methods: This was a controlled implementation study carried out in three districts, where four health centres and 16 villages in each district were selected and randomly assigned to intervention and control arms which implemented MDA campaigns using the CDI approach and the standard practice, respectively. Cross-sectional and mixed methods approach to data collection was used focusing on quantitative data for coverage and knowledge levels and qualitative data to assess perceptions of health providers and beneficiaries at baseline and follow-up assessments. Quantitative and qualitative data were analyzed using IBM SPSS software version 26 and NVivo 12 for Windows, respectively. Results: At follow-up, knowledge levels increased, majority of the respondents were more knowledgeable about what schistosomiasis was (41%-44%), its causes (41%-44%) and what STH were (48%-64%), while knowledge on intermediate host for schistosomiasis (19%-22%), its types (9%-13%) and what causes STH (15%-16%) were less known both in intervention and control arm communities. High coverage rates for praziquantel were registered in intervention (83%-89%) and control (86%-89%) communities, intervention (59%-79) and control (53%-86%) schools. Costs for implementation of the study indicated that the intervention arm used more resources than the control arm. Health workers and community members perceived the use of the CDI approach as a good initiative and more favorable over the standard practice. Conclusions: The use of the CDI in delivery of MDA campaigns against schistosomiasis and STH appears feasible, retains high coverages and is acceptable in intervention communities. Despite the initial high costs incurred, embedding into community delivery platforms could be considered as a possible way forward addressing the sustainability concern when current donor support wanes. Trial registration: Pan-African Clinical Trials Registry PACTR202102477794401, date: 25/02/2021.

: Almost all human giardiasis infections are caused by Giardia duodenalis assemblages A and B. Differentiation between human infections with these assemblages, as well as between single-assemblage (A or B) and mixed-assemblage (A and B) infections, is therefore needed to better understand the pathological impact of infection with either, or both, assemblages. We assessed the prevalence of G. duodenalis assemblages A and B using 305 fecal samples provided by school-age children situated along the southern shoreline of Lake Malawi. Concurrently, intestinal pathology data were also collected to test for association(s) between assemblage infection status and intestinal health. Prevalence of G. duodenalis infection was 39.3% by real-time polymerase chain reaction. Of all identified infections, 32% were single G. duodenalis assemblage A and 32% were single G. duodenalis assemblage B, whereas 33% were mixed-assemblage infections. Fifteen unique G. duodenalis assemblage A and 13 unique G. duodenalis assemblage B β-giardin haplotypes were identified. There was a positive association between single infection with G. duodenalis assemblage B and both self-reporting of abdominal pain (odds ratio [OR]: 3.05, P = 0.004) and self-reporting of diarrhea (OR: 3.1, P = 0.003). No association between single infection with assemblage A and any form of intestinal pathology was found. Additionally, there was a positive association between mixed-assemblage infections and self-reporting of abdominal pain (OR: 3.1, P = 0.002). Our study highlights the importance G. duodenalis assemblage typing and reaffirms the need for improved access to water, sanitation and hygiene infrastructure in rural areas of low- and middle-income countries.

In November 2017, Biomphalaria pfeifferi, the key intermediate host for Schistosoma mansoni in Africa, was first reported in Lake Malawi, Mangochi District. Two subsequent malacological surveys in 2018 and 2019 confirmed its lacustrine presence, as well as its presence along the Upper Shire River. These surveys provided sufficient specimens for analyses of the genetic structure and a transmission assessment for intestinal schistosomiasis. A total of 76 collected snails were characterized by a DNA sequence analysis of a 650 bp fragment of the mitochondrial cytochrome oxidase subunit 1 (cox1); by size fractionation of six fluorescently labelled microsatellite loci (Bgμl16, Bgμl, Bpf8, rg6, U-7, and rg9);by denaturing PAGE; and by detection of pre-patent Schistosoma infection by real-time PCR with a TaqMan^® probe. Five closely related cox1 haplotypes were identified, all present within a single location, with only one haplotype common across all the other locations sampled. No allelic size variation was detected with the microsatellites and all loci were monomorphic. Overall, the pre-patent prevalence of Schistosoma spp. was 31%, with infected snails found at several sampling locations. In this part of Lake Malawi, Bi. pfeifferi exhibits low genetic diversity and is clearly being exposed to the miracidia of S. mansoni, which is likely facilitating the autochthonous transmission of this parasite.

The freshwater snail genus Bulinus plays a vital role in transmitting parasites of the Schistosoma haematobium group. A hybrid schistosome between S. haematobium and S. mattheei has been recently detected using DNA-based identification methods in school children along the Lake Malawi shoreline in Mangochi District. This finding raised the need for contemporary revaluation of local interactions between schistosomes and snails, with a particular focus on snail species within the Bulinus africanus group. In 2017 and 2018, malacological surveys sampled several freshwater sites in Mangochi District. Collected snails (n = 250) were characterised using cytochrome oxidase subunit 1 gene (cox1), with DNA barcoding of the ‘Folmer’ region and a rapid PCR-RFLP typing assay with double digestion with HaeIII and SacI restriction enzymes. DNA cox1 sequence analysis, with phylogenetic tree construction, suggested the presence of at least three B. africanus group taxa in Lake Malawi, B. globosus, alongside first reports of B. africanus and B. angolensis, which can be differentiated by PCR-RFLP methods. In addition, a total of 30 of the 106 B. africanus group snails (28.30%) were positive to the Schistosoma-specific screen using real-time PCR methods. This study provides new insight into the recent changes in the epidemiology of urogenital schistosomiasis as likely driven by a new diversity of B. africanus group snails within the Lake.

Schistosome eggs cause granulomata and pathological abnormalities, detectable with non-invasive radiological techniques such as ultrasonography which could be useful in male genital schistosomiasis (MGS). As part of our novel MGS study among fishermen along Lake Malawi, we describe pathologies observed on ultrasonography and praziquantel (PZQ) treatment over time. Fishermen aged 18+ years were recruited, submitted urine and semen for parasitological and molecular testing, and thereafter, transabdominal pelvic and scrotal ultrasonography, assessing pathologies in the prostate, seminal vesicles, epididymis and testes. Standard PZQ treatment and follow-up invitation at 1-, 3-, 6- and 12-months’ time-points were offered. A total of 130 recruited fishermen underwent ultrasonography at baseline (median age: 32.0 years); 27 (20.9%, n = 129) had S. haematobium eggs in urine (median: 1.0 egg/10 mL), 10 (12.3%, n = 81) in semen (defined as MGS, median: 2.9 eggs/mL ejaculate) and 16 (28.1%, n = 57) had a positive seminal Schistosoma real-time PCR. At baseline, 9 fishermen (6.9%, n = 130) had abnormalities, with 2 positive MGS having prostatic and testicular nodules. Fewer abnormalities were observed on follow-up. In conclusion, pathologies detected in male genitalia by ultrasonography can describe MGS morbidity in those with positive parasitological and molecular findings. Ultrasonography advances and accessibility in endemic areas can support monitoring of pathologies’ resolution after treatment.