Citizens can help to map putative transmission sites for snail-borne diseases.

INTRODUCTION: Schistosomiasis and fasciolosis are snail-borne diseases of great medical and veterinary health importance. The World Health Organization recommends complementing drug treatment with snail control and community involvement for disease elimination, but there is a general lack of snail experts and hence snail distribution data. Therefore, we adopted a citizen science approach and involved citizens in the monitoring of medically and veterinary important snail taxa. MATERIALS AND METHODS: Snail data was collected weekly by 25 trained citizen scientists (CSs) at 76 sites around southern Lake Albert (Uganda) for 20 months. At each site, snails were searched for 30 minutes, sorted, target snail hosts identified to genus level, counted and data submitted through a smartphone application. The quality of this data was assessed by comparing it to monthly data collected by an 'expert' malacologist using the same sampling protocol. Generalised binomial logistic and linear mixed-effects models were used to analyse the variables for agreement between the CSs and expert. FINDINGS: The binary agreement in presence/absence of Biomphalaria, Bulinus and Radix snails reported by the expert and CSs ranged between 70% and 86% (900 reports) with an average of 17% false negatives (sites wrongly defined as snail-free). The agreement for Biomphalaria and Radix increased with snail abundance, and false negatives decreased when the number of snails collected by citizens was aggregated per month. Site type significantly predicted binary agreement, which was lowest at lake sites (55%) and highest at spring sites (99%) with variations across genera. Similar temporal trends in snail abundance were recorded despite the expert reporting higher abundance. However, the relative abundance was consistent across site types. The match between the sites with highest Biomphalaria spp. abundance identified by CSs and expert was consistently high (~84.1%) and increased over time. CONCLUSIONS AND RECOMMENDATIONS: Our results demonstrate the potential of citizen science to map putative schistosomiasis transmission sites. We therefore argue that this inclusive, powerful and cost-effective approach can be more sustainable than top-down monitoring and intervention campaigns.

An accident waiting to happen? Exposing the potential of urogenital schistosomiasis transmission in the Lake Albert region, Uganda.

BACKGROUND: Urogenital schistosomiasis caused by the parasitic blood fluke Schistosoma haematobium is the most common form of that constitutes a majority of over 240 million schistosomiasis cases. The enigmatic absence of urogenital schistosomiasis in Uganda has, until now, been attributed to the absence of substantial populations of suitable snail intermediate hosts. METHODS: Malacological surveys were carried out in 73 sites southeast of Lake Albert, Uganda in October and November 2020. Collected snails were transported to the laboratory for identification. The snails were identified using partial mitochondrial cytochrome c oxidase subunit one and nuclear internal transcribed spacer barcoding. Schistosome infections in snails were also assessed using cercarial shedding and rapid diagnostic PCR techniques. RESULTS: We found Bulinus globosus and Bulinus nasutus productus, the main intermediate species in the transmission of S. haematobium in mainland East Africa. In this survey, B. globosus was more common than B. nasutus productus, with the former reported at four sites (total count = 188) and the latter reported at one site (total count = 79). Molecular testing revealed a high prevalence of Schistosoma bovis in B. nasutus productus (16%), but no S. haematobium infections were found. CONCLUSIONS: Given the abundance of snail hosts and the risky human water contact behaviours observed, we highlight the potential for urogenital schistosomiasis transmission in the region.

Phytochemical profile and antimicrobial activity of the leaves and stem bark of Symphonia globulifera L.f. and Allophylus abyssinicus (Hochst.) Radlk.

INTRODUCTION: Symphonia globulifera and Allophylus abyssinicus are used in the management of skin rashes and sores, cough, malaria, digestive diseases, stomach ache, wounds and helminthic infections among others in Uganda, Kenya, Ethiopia, Cameroon. This study aimed at determining the phytochemical profile and antimicrobial activity of these two plants. METHODS: The stem bark and leaves of both plants were collected from Bwindi Impenetrable National Park and air-dried under shade at room temperature. Cold maceration, decoction and infusion with methanol, water and ethyl acetate as solvents were used in phytochemical extraction. Preliminary qualitative screening and thin layer chromatography were used for phytochemical profiling. Antimicrobial activity was analysed by agar well diffusion assay, broth macro-dilution assay and fractional inhibition concentration index (FICI). RESULTS: The leaves and stem bark of both plants have a diverse set of phytochemical compounds of variable polarity including, tannins, alkaloids, flavonoids, saponins, quinones and anthraquinones among others. Generally, methanol and water extracts of S. globulifera and A. abyssinicus had in-vitro bactericidal activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa but weak fungistatic activity against Candida albicans. Allophylus abyssinicus leaf water and S. globulifera leaf methanol extract combination had a synergistic activity (ΣFICI = 0.37) against S. aureus. Similarly, A. abyssinicus stem bark water extract and A. abyssinicus leaf water extract combination had an additive effect (ΣFICI = 1) against P. aeruginosa. CONCLUSION: The leaves and stem bark crude extracts of S. globulifera and A. abyssinicus possess a wide range of bioactive phytochemical compounds but have weak antimicrobial activity against S. aureus, E. coli, P. aeruginosa and C. albicans.

Molecular identification of Bulinus spp. intermediate host snails of Schistosoma spp. in crater lakes of western Uganda with implications for the transmission of the Schistosoma haematobium group parasites.

BACKGROUND: Human schistosomiasis is the second most important tropical disease and occurs in two forms in Africa (intestinal and urogenital) caused by the digenetic trematodes Schistosoma mansoni and Schistosoma haematobium, respectively. A proposed recent shift of schistosomiasis above a previously established altitudinal threshold of 1400 m above sea level in western Ugandan crater lakes has triggered more research interest there. METHODS: Based on extensive field sampling in western Uganda and beyond and employing an approach using sequences of the mitochondrial barcoding gene cytochrome c oxidase subunit 1 (cox1) this study aims were: (i) identification and establishment of the phylogenetic affinities of Bulinus species as potential hosts for Schistosoma spp.; (ii) determining diversity, frequency and distribution patterns of Bulinus spp.; and (iii) establishing genetic variability and phylogeographical patterns using Bayesian inference and parsimony network analyses. RESULTS: Out of the 58 crater lakes surveyed, three species of Bulinus snails were found in 34 crater lakes. Bulinus tropicus was dominating, Bulinus forskalii was found in two lakes and Bulinus truncatus in one. The latter two species are unconfirmed potential hosts for S. haematobium in this region. However, Bulinus tropicus is an important species for schistosomiasis transmission in ruminants. Bulinus tropicus comprised 31 haplotypes while both B. forskalii and B. truncatus exhibited only a single haplotype in the crater lakes. All species clustered with most of the haplotypes from surrounding lake systems forming source regions for the colonization of the crater lakes. CONCLUSIONS: This first detailed malacological study of the crater lakes systems in western Uganda revealed presence of Bulinus species that are either not known or not regionally known to be hosts for S. haematobium, the causing agent of human urogenital schistosomiasis. Though this disease risk is almost negligible, the observed dominance of B. tropicus in the crater lakes shows that there is a likelihood of a high risk of infections with Schistosoma bovis. Thus, extra attention should be accorded to safeguard wild and domestic ruminants in this region as the population benefits from these animals.

Traditional eye medicine use in microbial keratitis in Uganda: a mixed methods study.

Background: Traditional eye medicine (TEM) is frequently used to treat microbial keratitis (MK) in many parts of Africa. Few reports have suggested that this is associated with a worse outcome. We undertook this large prospective study to determine how TEM use impacts presentation and outcome of MK and to explore reasons why people use TEM for treatment in Uganda. Methods: In a mixed method prospective cohort study, we enrolled patients presenting with MK at the two main eye units in Southern Uganda between December 2016 and March 2018 and collected information on history, TEM use, microbiology and 3-month outcomes. We conducted qualitative interviews with patients, carers traditional healers on reasons why people use TEM. Outcome measures included presenting vision and at 3-months, comparing TEM Users versus Non-Users. A thematic coding framework was deployed to explore reasons for use of TEM. Results: Out of 313 participants enrolled, 188 reported TEM use. TEM Users had a delayed presentation; median presenting time 18 days versus 14 days, p= 0.005; had larger ulcers 5.6 mm versus 4.3 mm p=0.0005; a worse presenting visual acuity median logarithm of the minimum angle of resolution (Log MAR) 1.5 versus 0.6, p=0.005; and, a worse visual acuity at 3 months median Log MAR 0.6 versus 0.2, p=0.010. In a multivariable logistic regression model, distance from the eye hospital  and delayed presentation were associated with TEM use. Reasons for TEM use included lack of confidence in conventional medicine, health system breakdown, poverty, fear of the eye hospital, cultural belief in TEM, influence from traditional healers, personal circumstances and ignorance. Conclusion: TEM users had poorer clinical presentation and outcomes. Capacity building of the primary health centres to improve access to eye care and community behavioural change initiatives against TEM use should be encouraged.