[Relation between Shistosoma mansoni and hepatosplenomegalies].

Introduction: Although they remain a neglected transmissible disease, affecting mainly people in poor countries, the combined forms of schistosomiasis are second only to malaria as a major parasitic disease. Although both urinary and intestinal schistosomiasis are endemic in Madagascar, this study focuses only on the intestinal forms. The symptoms may remain unnoticed or be ignored, for the seriousness of intestinal schistosomiasis is due mainly to its hepatosplenic complications.

Objectives: To estimate the etiological fraction of Schistosoma mansoni involved in hepatomegaly (HM), splenomegaly (SM) and hepatosplenomegaly (HSM), with or without signs of portal hypertension (PHT).

Methods: This file-based retrospective study includes patients admitted to the University Hospital of Antananarivo, Madagascar, between January 2005 and July 2008, who presented with HM, SM, HSM and/or PHT. The case was attributed to schistosomiasis if blood serology, tested with ELISA, was positive for this parasite. The statistical analysis used three approaches: a cross-sectional approach, a longitudinal approach (retrospective cohort), and a "case-control" approach.

Results: Of 7308 admissions during this period, 269 (4%) were diagnosed with a hepatosplenic complication and were retained. The average age (+/- standard deviation) was 47.8 (+/- 16.4) years. HM accounted for 55.4% of cases, SM 18.9%, HTP 18.6% and HSM 18.6%. Serology was positive for schistosomiasis in 21.6% of cases. The sex ratio (men:women) for these cases was 1.9, and 67.3% of the patients were aged 30 years or older. The main schistosomiasis complications were SM (n=22) and HTP (n=22). The age group most affected depended on the specific complication: for HM, 28.6% of patients were aged between 40 and 49 years; for HSM, 57.1% were aged between 30 and 40 years. The prevalence of SM was lower in subjects between 50 and 59 years of age (4.5%) than the other complications. Patients with positive serology results were significantly younger than those with negative results, or whose serology was not checked (37.8 years vs. 50.5 years, p < 0.001). Stratification according to complication showed that the etiological fraction of schistosomiasis was 76% for patients with SM, 79% for HTP, 58% for HSM and 4.9% for HM. The retrospective cohort and the case-control analyses both showed that a history of dysentery and frequent contact with water were the main factors associated with complicated schistosomiasis. It is important to note that urban and rural residents had the same risk of developing schistosomiasis with complications (OR: 0.9 [0.4; 1.9]).

Conclusion: This study showed that schistosomiasis infection is strongly associated with hepatosplenic pathologies. One of the shortcomings of the study is the absence of any analysis of the course and outcome in the study patients. Nevertheless, the course of oesophageal varices, SM or HSM in patients with HTP indicates that schistosomiasis was often fatal.