All that is blood is not schistosomiasis : experiences with reagent strip testing for urogenital schistosomiasis with special consideration to very-low prevalence settings

Reagent strip testing for microhaematuria has long been used for community diagnosis of Schistosoma haematobium. Sensitivities and specificities are reasonable, and hence, microhaematuria can serve as a proxy for S. haematobium infection. However, assessment of test performance in the context of the underlying S. haematobium prevalence is rare and test parameters other than sensitivity and specificity have been neglected.; Data about the association between microhaematuria and urine filtration results from three studies were compared and put into context with findings from a recent Cochrane review. Data were stratified by S. haematobium prevalence to identify prevalence-related differences in test performance. Kappa agreement and regression models were employed to compare data for different S. haematobium prevalence categories.; We found a "background" prevalence of microhaematuria (13 %, on average) which does not seem to be associated with schistosomiasis in most settings, irrespective of the prevalence of S. haematobium. This background level of microhaematuria might be due to cases missed with urine filtration, or alternative causes apart from S. haematobium. Especially in very-low prevalence settings, positive results for microhaematuria likely give an inaccurate picture of the extent of S. haematobium, whereas negative results are a sound indicator for the absence of infection.; Reagent strip testing for microhaematuria remains a good proxy for urogenital schistosomiasis, but implications of test results and scope of application differ depending on the setting in which reagent strips are employed. In very-low prevalence settings, microhaematuria is an unstable proxy for urogenital schistosomiasis and treatment decision should not be based on reagent strip test results alone. Our findings underscore the need for highly accurate diagnostic tools for settings targeted for elimination of urogenital schistosomiasis

Access to, and use of, water by populations living in a schistosomiasis and fascioliasis co-endemic area of northern Côte d'Ivoire

Water is an essential element of life, but it can also be a source of disease. Apart from direct consumption of unsafe water, direct contact and indirect consumption puts people at risk of many different types of pathogens. Employing a mixed methods approach, consisting of questionnaires and direct observations, we assessed access to, and use of, different water sources by the participants of the district des Savanes in northern Côte d'Ivoire. The use of water sources was put in relation to the potential risk of acquiring schistosomiasis and fascioliasis. Overall, 489 people aged 8 to 82 years participated. While all participants had access to safe water, 63% were in direct contact with unimproved water and 31% directly consumed unsafe water. More than a third of the people who otherwise reported using only improved water for all activities came in contact with unimproved water through crossing open water when going to their workplace, school or other destinations. Self-reported blood in urine - a marker for Schistosoma haematobium with reasonable sensitivity and specificity - was reported by 6% (n=30), self-reported blood in stool - an unspecific marker for Schistosoma mansoni - was reported by 7% (n=35), while blood co-occurring in both urine and stool was reported by another 10% (n=48) of participants. Accessing unimproved water for any activity (including crossing) was associated with higher odds of reporting blood in urine and/or blood in stool (odds ratio: 1.90; 95% confidence interval: 1.07-3.36). Our results have important rami-fications for intervention programmes targeting neglected tropical diseases, and emphasize the need for a wider supply of safe water to rural populations, since the water supply at the workplace needs to be considered as well next to the water supply at home. Crossing of open water sources is an important risk factor for sustained transmission of schistosomiasis

Intermediate host snails of schistosomes shedding cercariae in 16 localities from four departments in North Côte d’Ivoire, August 2018.

Intermediate host snails of schistosomes shedding cercariae in 16 localities from four departments in North Côte d’Ivoire, August 2018.</p

Characteristics of the study population (N = 742) in four departments in North Côte d’Ivoire in August 2018.

Characteristics of the study population (N = 742) in four departments in North Côte d’Ivoire in August 2018.</p

Classification of intensity for schistosome and hookworm infections [28].

Classification of intensity for schistosome and hookworm infections [28].</p

Snail species identified in 16 localities from four departments in North Côte d’Ivoire in August 2018.

Snail species identified in 16 localities from four departments in North Côte d’Ivoire in August 2018.</p

Prevalence of <i>Schistosoma haematobium</i> and hookworm, stratified by occupation, in four departments of North Côte d’Ivoire in August 2018.

Prevalence of Schistosoma haematobium and hookworm, stratified by occupation, in four departments of North Côte d’Ivoire in August 2018.</p

Map of the 16 study sites in the four departments of North Côte d’Ivoire, surveyed for schistosomiasis and soil-transmitted helminthiasis in August 2018.

The map was created with QGIS software version 2.16.0 ‘Nødebo’ (QGIS Development Team), using a basemap shapefile from the Database of Global Administrative Areas (GADM, https://gadm.org/; license: https://gadm.org/license.html).</p

Prevalence of <i>Schistosoma haematobium</i>, <i>S</i>. <i>mansoni</i>, and hookworm infections in the study population (N = 742) in four departments, North Côte d’Ivoire, August 2018.

Prevalence of Schistosoma haematobium, S. mansoni, and hookworm infections in the study population (N = 742) in four departments, North Côte d’Ivoire, August 2018.</p

Intensity categories of <i>S</i>. <i>haematobium</i> and hookworm infection, stratified by participant age groups, in four departments of North Côte d’Ivoire in August 2018.

For the definition of infection intensities, see Table 1.</p