A temporal study of Hymenolepis nana infections in man in an endemic area was conducted in the Punjab Region of West Pakistan. Infection rates were highest in the age-group 2 to 19 years and transmission appeared to be hand-to-mouth rather than through a rodent reservoir. The optimum time for transmission appeared to be during the warmer months of the year (May to October) which coincided with the greatest amount of rainfall. Although the prevalence of H. nana in our study group of 93 children and adolescents was similar at the beginning and end of the study which covered 22 months, there was an active turnover of this parasite in the study group. That H. nana can persist in man in endemic areas for long periods of time was demonstrated by the fact that 26% of the participants were infected for the entire study period. There appeared to be no correlation between systemic disturbances, such as those indicated by diarrheal stools or abnormal eosinophil counts, and H. nana infections.
Present address: Department of Biology, Austin College, Sherman, Texas 75090.
Present address: Department of Zoology, University of Maryland, College Park, Maryland.