Rapid, low-cost, species-specific diagnosis, based upon DNA testing, is becoming important in the treatment of patients with infectious diseases. Here, we demonstrate an innovation that uses origami to enable multiplexed, sensitive assays that rival polymerase chain reactions (PCR) laboratory assays and provide high-quality, fast precision diagnostics for malaria. The paper-based microfluidic technology proposed here combines vertical flow sample-processing steps, including paper folding for whole-blood sample preparation, with an isothermal amplification and a lateral flow detection, incorporating a simple visualization system. Studies were performed in village schools in Uganda with individual diagnoses being completed in <50 min (faster than the standard laboratory-based PCR). The tests, which enabled the diagnosis of malaria species in patients from a finger prick of whole blood, were both highly sensitive and specific, detecting malaria in 98% of infected individuals in a double-blind first-in-human study. Our method was more sensitive than other field-based, benchmark techniques, including optical microscopy and industry standard rapid immunodiagnostic tests, both performed by experienced local healthcare teams (which detected malaria in 86% and 83% of cases, respectively). All assays were independently validated using a real-time double-blinded reference PCR assay. We not only demonstrate that advanced, low-cost DNA-based sensors can be implemented in underserved communities at the point of need but also highlight the challenges associated with developing and implementing new diagnostic technologies in the field, without access to laboratories or infrastructure.

In Uganda, control of intestinal schistosomiasis with preventive chemotherapy is typically focused towards treatment of school-aged children; the needs of younger children are presently being investigated as in lakeshore communities very young children can be infected. In the context of future epidemiological monitoring, we sought to compare the detection thresholds of available diagnostic tools for Schistosoma mansoni and estimate a likely age of first infection for these children. A total of 242 infants and preschool children (134 boys and 108 girls, mean age 2.9 years, minimum 5 months and maximum 5 years) were examined from Bugoigo, a well-known disease endemic village on Lake Albert. Schistosome antigens in urine, eggs in stool and host antibodies to eggs were inspected to reveal a general prevalence of 47.5% (CI₉₅ 41.1–54.0%), as ascertained by a positive criterion from at least one diagnostic method. Although children as young as 6 months old could be found infected, the average age of infected children was between 3¼–3¾ years, when diagnostic techniques became broadly congruent. Whilst different assays have particular (dis)advantages, direct detection of eggs in stool was least sensitive having a temporal lag behind antigen and antibody methods. Setting precisely a general age of first infection is problematic but if present Ugandan policies continue, a large proportion of infected children could wait up to 3–4 years before receiving first medication. To better tailor treatment needs for this younger ageclass, we suggest that the circulating cathodic antigen urine dipstick method to be used as an epidemiological indicator. In sub-Saharan Africa, intestinal schistosomiasis is a debilitating disease caused by a worm infection. To arrest disease progression, de-worming medications are given out, often en masse, to school-aged children. In Uganda, however, much younger children can be infected, and in lakeshore communities both infants and pre-school children can already show signs and symptoms of intestinal schistosomiasis. To change de-worming practices, further information on the occurrence of infections in these younger is needed for evidence-based decision making. Our study applied current methods of disease diagnosis to better define the ‘age of first infection’ and estimate general infection prevalence within a disease-endemic village. Up to 50% of young children were clearly shown to have schistosomiasis and could likely wait up to 3–4 years before obtaining first treatment if present de-worming policies are not changed. In the context of identifying future treatment needs, we propose that antigen detection methods are most suitable.

For disease surveillance and mapping within large-scale control programmes, RDTs are becoming popular. For intestinal schistosomiasis, a commercially available urine-dipstick which detects schistosome circulating cathodic antigen (CCA) in host urine is being increasingly applied, however, further validation is needed. In this study, we compared the CCA urine-dipstick test against double thick Kato-Katz faecal smears from 171 schoolchildren examined along the Tanzanian and Kenyan shorelines of Lake Victoria. Diagnostic methods were in broad agreement; the mean prevalence of intestinal schistosomiasis inferred by Kato-Katz examination was 68.6% (95% confidence intervals (CIs) = 60.7-75.7%) and 71.3% (95% CIs = 63.9-78.8%) by CCA urine-dipsticks. There were, however, difficulties in precisely 'calling' the CCA test result, particularly in discrimination of 'trace' reactions as either putative infection positive or putative infection negative, which has important bearing upon estimation of mean infection prevalence; considering 'trace' as infection positive mean prevalence was 94.2% (95% CIs = 89.5-97.2%). A positive association between increasing intensity of the CCA urine-dipstick test band and faecal egg count was observed. Assigning trace reactions as putative infection negative, overall diagnostic sensitivity (SS) of the CCA urine-dipstick was 87.7% (95% CIs = 80.6-93.0%), specificity (SP) was 68.1% (95% CIs = 54.3-80.0%), positive predictive value (PPV) was 86.1% (95% CIs = 78.8-91.7%) and negative predictive value (NPV) was 71.1% (95% CIs = 57.2-82.8%). To assist in objective defining of the CCA urine-dipstick result, we propose the use of a simple colour chart and conclude that the CCA urine-dipstick is a satisfactory alternative, or supplement, to Kato-Katz examination for rapid detection of intestinal schistosomiasis.

The World Health Organization (WHO) recommends praziquantel mass drug administration (MDA) to control schistosomiasis in endemic regions. We aimed to quantify recent and lifetime praziquantel coverage, and reasons for non-treatment, at an individual level to guide policy recommendations to help Uganda reach WHO goals. Cross-sectional household surveys (n = 681) encompassing 3208 individuals (adults and children) were conducted in 2017 in Bugoto A and B, Mayuge District, Uganda. Participants were asked if they had received praziquantel during the recent MDA (October 2016) and whether they had ever received praziquantel in their lifetime. A multivariate logistic regression analysis with socio-economic and individual characteristics as covariates was used to determine factors associated with praziquantel uptake. In the MDA eligible population (≥5 years of age), the most recent MDA coverage was 48.8%. Across individuals’ lifetimes, 31.8% of eligible and 49.5% of the entire population reported having never taken praziquantel. Factors that improved individuals’ odds of taking praziquantel included school enrolment, residence in Bugoto B and increasing years of village-residency. Not being offered (49.2%) and being away during treatment (21.4%) were the most frequent reasons for not taking the 2016 praziquantel MDA. Contrary to expectations, chronically-untreated individuals were rarely systematic non-compliers, but more commonly not offered treatment.

SUMMARY: During a longitudinal study investigating the dynamics of malaria in Ugandan lakeshore communities, a consistently high malaria prevalence was observed in young children despite regular treatment. To explore the short-term performance of artemether-lumefantrine (AL), a pilot investigation into parasite carriage after treatment(s) was conducted in Bukoba village. A total of 163 children (aged 2–7 years) with a positive blood film and rapid antigen test were treated with AL; only 8·7% of these had elevated axillary temperatures. On day 7 and then on day 17, 40 children (26·3%) and 33 (22·3%) were positive by microscopy, respectively. Real-time PCR analysis demonstrated that multi-species Plasmodium infections were common at baseline, with 41·1% of children positive for Plasmodium falciparum/Plasmodium malariae, 9·2% for P. falciparum/ Plasmodium ovale spp. and 8·0% for all three species. Moreover, on day 17, 39·9% of children infected with falciparum malaria at baseline were again positive for the same species, and 9·2% of those infected with P. malariae at baseline were positive for P. malariae. Here, chronic multi-species malaria infections persisted in children after AL treatment(s). Better point-of-care diagnostics for non-falciparum infections are needed, as well as further investigation of AL performance in asymptomatic individuals.