Acute schistosomiasis (Katayama fever) may present with a broad spectrum of 
symptoms three to six weeks after primary infection by Schistosoma (S) mansoni, 
S. japonicum or, more rarely, S. haematobium. The acute phase of schistosomiasis 
is frequently confused with other feverish diseases. It occurs almost 
exclusively in nonimmune visitors to endemic areas. We describe seven cases of 
acute S. mansoni infection. The pathogenesis, clinical features, diagnosis and 
treatment are briefly discussed. Katayama fever should be considered in patients 
returning from endemic areas with fever and eosinophilia. Clinically normal, but 
potentially exposed travel companions should be examined as well. Early 
diagnosis and treatment may be important in preventing the infection's serious 
sequelae of the infection.