SEASONAL INFECTIONS 



205 



More than one month is listed for a "peak" or a "low" when the 

 percentages were the same for those months. For the three rare cercariae 

 the "lows" were actually non-appearances during the months listed. 

 Heterophyid cercariae, Euhaplorchis calif orniensis and Parastictodora 



100 



90 - 



• ' 

 70 !> 

 60 



e 



o 50 



M 



2 40 



T. 50 



M 



U 



c to 



M 

 A. 



10 



T r 



T r 



T 1 1 r 



> 

 o 





Ik 



< 

 s 







Ul 



c» 



Ml 

 M 



»- 



o 



o 



Figure I 



hancocki, and xiphidiocercariae were more frequently found than were 

 those of other types. Infections with Euhaplorchis calif orniensis varied 

 from a low of 10 per cent in February to a high of 27 per cent in March. 

 Infections of the small xiphidiocercaria, next to E. californiensis in fre- 

 quency, ranged from a low of 4 per cent in July to a peak of 22 per cent 

 in October. 



