Schistosomiasis and hydration status: Schistosoma haematobium, but not Schistosoma mansoni increases urine specific gravity among rural Tanzanian women.

OBJECTIVES: Schistosome infections can damage organs important for water homeostasis, especially the kidneys. Urogenital schistosomiasis (caused by Schistosoma haematobium) increases protein and blood in urine and intestinal schistosomiasis (caused by S. mansoni) affects total body water. However, no data exist on how different schistosome species affect urine specific gravity (USG), a hydration biomarker. Therefore, we assessed the relationship between S. haematobium- and S. mansoni-infected and uninfected women and USG in rural Tanzania.
MATERIALS AND METHODS: Surveys were conducted and stool and urine samples were collected among 211 nonpregnant women aged 18-50. S. haematobium eggs were detected using the urine filtration method. S. mansoni eggs were detected using the Kato Katz method. USG was measured using a refractometer and analyzed as both a continuous and dichotomous variable. Regression (linear/logistic) models were estimated to test the relationship between infection and hydration status.
RESULTS: The prevalence of S. haematobium was 5.9% and S. mansoni was 5.4% with no coinfections. In regression models, S. haematobium-infected women had significantly higher USG (Beta = 0.007 g mL-1 ; standard error = 0.002; p = 0.001) and odds (Odds ratio: 7.76, 95% CI: 1.21-49.5) of elevated USG (>1.020 g mL-1 ) than uninfected women, whereas S. mansoni-infected women did not. DISCUSSION: Schistosoma haematobium, but not S. mansoni, infection is associated with higher USG and risk of inadequate hydration. Future work should determine whether findings are attributable to parasite-induced debris in urine or urinary tract pathologies and signs of renal damage. Human and non-human primate studies using USG in schistosome-endemic areas should account for schistosomiasis.