Morbidity associated with Schistosoma mansoni infection in north-eastern Democratic Republic of the Congo

BackgroundReducing morbidity is the main target of schistosomiasis control efforts, yet only rarely do control programmes assess morbidity linked to Schistosoma sp. infection. In the Democratic Republic of Congo (DRC), and particularly in north-eastern Ituri Province, little is known about morbidity associated with Schistosoma mansoni infection. For this reason, we aimed to assess intestinal and hepatosplenic morbidity associated with S. mansoni infection in Ituri Province. Methods/Principal findingsIn 2017, we conducted a cross-sectional study in 13 villages in Ituri Province, DRC. S. mansoni infection was assessed with a Kato-Katz stool test (2 smears) and a point-of-care circulating cathodic antigen (POC-CCA) urine test. A questionnaire was used to obtain demographic data and information about experienced intestinal morbidity. Each participant underwent an abdominal ultrasonography examination to diagnose hepatosplenic morbidity. Of the 586 study participants, 76.6% tested positive for S. mansoni. Intestinal morbidity reported in the two preceding weeks was very frequent, and included abdominal pain (52.7%), diarrhoea (23.4%) and blood in the stool (21.5%). Hepatosplenic morbidity consisted of abnormal liver parenchyma patterns (42.8%), hepatomegaly (26.5%) and splenomegaly (25.3%). Liver pathology (adjusted odds ratio [aOR] 1.20, 95% confidence interval [CI] 1.06-1.37, p = 0.005) was positively and significantly associated with S. mansoni infection. Hepatomegaly (aOR 1.52, 95% CI 0.99-2.32, p = 0.053) and splenomegaly (aOR 1.12, 95% CI 0.73-1.72, p = 0.619) were positively but not significantly associated with S. mansoni infection at the individual level. At the village level, S. mansoni prevalence was positively associated with the prevalence of hepatomegaly and splenomegaly. High-intensity S. mansoni infections were associated with diarrhoea, blood in the stool, hepatomegaly, splenomegaly, and liver parenchyma (C, D, E and F pathology patterns). Four study participants were diagnosed with ascites and five reported hematemesis. Conclusions/SignificanceOur study documents a high burden of intestinal and hepatosplenic morbidity associated with S. mansoni infection status in Ituri Province. The findings call for targeted interventions to address both S. mansoni infection and related morbidity. Author summarySchistosomiasis caused by Schistosoma mansoni is of great public health importance in sub-Saharan Africa. The World Health Organization (WHO) recommends that control efforts aim to reduce morbidity through large-scale intervention programmes. However, intestinal and liver morbidity is rarely assessed in such control programmes. Hence, little is known about (i) the magnitude of the intestinal and liver morbidity burden in the community, or about (ii) the morbidity associated with S. mansoni infection, specifically. We conducted a cross-sectional study in which we assessed intestinal morbidity by questionnaire and liver morbidity by abdominal ultrasonography. Additionally, we determined the infection status of the study participants using standard diagnostic procedures (Kato-Katz technique and point-of-care cathodic circulating S. mansoni antigen [POC-CCA] urine test). Among the 586 study participants, aged six years and older, from 13 villages in Ituri Province, DRC, we observed a high degree of intestinal (23.4% with diarrhoea; 21.5% with blood in stool) and hepatosplenic morbidity (42.8% with abnormal liver C, D, E, and F patterns; 26.5% with an enlarged liver; 25.3% with an enlarged spleen). S. mansoni infection was associated with liver and spleen enlargement. Likewise, S. mansoni infection intensity was linked to diarrhoea, to liver and spleen enlargement and to pathological changes in the liver parenchyma. At village level, we observed that the prevalence of an enlarged liver and spleen among patients increased with the prevalence of S. mansoni infection. We conclude that the population of Ituri Province carries an alarming burden of intestinal, liver and spleen morbidity associated with S. mansoni infection. A comprehensive control programme to address this infection and disease burden is urgently required.

Automated summary

A cross-sectional study conducted in Ituri Province, DRC, found a high burden of intestinal and hepatosplenic morbidity associated with S. mansoni infection, including symptoms like abdominal pain, diarrhea, blood in the stool, abnormal liver patterns, hepatomegaly, and splenomegaly. Targeted interventions are needed to address both the infection and related morbidity.