ACKNOWLEDGMENTS 



The investigations reported in the following pages were carried on 

 as part of a project to study human onchocerciasis, jointly sponsored 

 by the Pan American Sanitary Bureau ; the Laboratory of Tropical 

 Diseases of the National Microbiological Institute, National Institutes 

 of Health, United States Public Health Service ; and the Ministry of 

 Health of the Republic of Guatemala. The project was supported 

 by a grant-in-aid from the Division of Research Grants and Fellow- 

 ships of the National Institutes of Health. The Laboratory of 

 Onchocerciasis, which served as the center for investigations, was 

 established at San Pedro Yepocapa, Department of Chimaltenango, 

 Guatemala. 



In connection with the studies accomplished during the period Au- 

 gust 1947 through June 1953, I am grateful to several persons who 

 have cooperated in various ways to make them possible : 



To J. Onofre Ochoa A., administrator of the Laboratory of Oncho- 

 cerciasis, whose loyalty and unceasing efforts have so markedly 

 facilitated the work. 



To the various employees in the laboratory and field who showed a 

 keen interest in the work and a desire to help in whatever way possible 

 to rid their region of onchocerciasis, and who, for extended periods, 

 also served as subjects for experiments described in this paper. 



To the owners and managers of the following plantations or organi- 

 zations who permitted me to carry out field studies on their property, 

 and some of whom also supplied meteorological and other data used 

 in this presentation : 



Amparo 



La Argentina 



La Cabana 



Candelaria 



La Ceiba 



La Conchita 



Miraflores 



Montellano 



Montevideo 



Morelia 



In San Pedro Yepocapa 



Niagara 



Nimaya 



Palo Verde 



Panajabal 



Pena Plata 



Recreo 



Recuerdo 



Rosario Chuarramos 



San Antonio Sumatan 



San Lucas Miramar 



San Rafael Sumatan 



Sta. Cristina 



Sta. Emilia 



Sta. Rosa Sumatan 



Sta. Sofia 



Sta. Teresa 



Sibaja 



La Trinidad 



La Victoria 



