Morbidity in schistosomiasis: an update.

PURPOSE OF REVIEW: Schistosomiasis is an important poverty-related health problem and more than 200 million people are infected. This review summarizes papers from April 2003 to June 2004 with a focus on schistosomiasis morbidity and the various factors that affect the level of morbidity in endemic populations. The aim is to provide an update on the current state of knowledge and, hopefully, thereby stimulate continued research interest in this important area.

RECENT FINDINGS: Research into the immune responses associated with severe morbidity has provided new insights into the mechanisms of immune regulation as well as the role of genetic predisposition to periportal fibrosis. Malaria and schistosomiasis are co-endemic and co-infection with malaria may increase the level of morbidity in hepatosplenic schistosomiasis, and alter the host immune response towards schistosome antigens. Schistosome infections may render the host more susceptible to human immunodeficiency virus infection by either interfering with immune responses or increasing the risk of transmission due to genital lesions. An important advance in schistosomiasis research, and parasite genomics, is the recent availability of two major Schistosoma mansoni and Schistosoma japonicum DNA bioinformatic resources.

SUMMARY: Significant advances have been achieved in our understanding of the epidemiology, immunology and genetics of schistosomiasis, and the various factors that may influence morbidity. However, good research is vital for sustainable disease control, and continued progress requires a critical mass of researchers with a range of expertise from basic parasite biology to public-health interventions. It is therefore important to strengthen research capacity in endemic countries.