Although schistosomiasis is not often fatal, it is so debilitating that it has become an economic drain on many developing countries.

• Ait is so debilitating that it has become an economic  
• Bit is of such debilitation, it has become an economical  
• Cso debilitating is it as to become an economic  
• Dsuch is its debilitation, it becomes an economical  
• Ethere is so much debilitation that it has become an economical