NO. I 



BLACK FLIES OF GUATEMALA — DALMAT 



25 



disease could become endemic. Surveys of these two plantations have 

 shown that both Simuliiim ochraceum and 5". metallicmn are pres- 

 ent in large numbers. Should a sufficiently large group of infected 

 individuals be introduced into the region at one time, transmission may 

 take place and the disease may then become established. Another 

 region, in the north-central Department of El Quiche, is similar in 



Map 13. 



altitude, meteorological conditions, crops, stream types, and species of 

 Simulium to regions within the onchocerciasis zones. In addition, nu- 

 merous residents of this large region migrate annually to the oncho- 

 cerciasis region to work on the cofifee plantations for about a 4-month 

 period, especially during the harvest. Many of these transient workers 

 have become infected, yet no endemic zone is believed to have become 

 established in El Quiche. This may be explained by the social organi- 

 zation in this department, a subject which is discussed in the following 

 section of this presentation. 



