The detection and epidemiology of parasitic gastrointestinal nematode infection in Zanzibari infants: The association between infection status of nursing infants and cytokines present in human milk

It is estimated that approximately half of the world's population harbors parasitic gastrointestinal (GI) nematode infections. Research and interventions have focused on women of reproductive age and school age children, because these populations suffer significant infection-associated morbidities. Interventions have not targeted preschool age children because of a presumed low prevalence and intensity of parasitic GI nematode infection in this group. Little is known about the health effects and epidemiology of infant parasitic GI nematode infection; however, there is recent evidence that infection in preschool age children can have detrimental effects on growth, and the work presented in this thesis demonstrates that a high prevalence of infection can be observed in infants residing in endemic areas.; Infants have a potential source of protection from parasitic worm infection that older children do not---their mother's breast milk. Animal studies have identified host cytokine responses that are associated with resistance or susceptibility to the establishment of parasitic GI nematode infection. Breast milk is an exogenous source of many of these same cytokines, and has the potential to influence the establishment of worm infection in nursing infants.; There is a lack of information about the day-to-day variability of cytokine concentrations in breast milk, but observations presented in this thesis, from a single donor's prospectively collected milk, suggests two, and possibly three, patterns of milk cytokine expression. This thesis culminates in a study that observed an association between the presence of cytokines in human milk and parasitic GI nematode infection in the nursing infant. However, two cytokines that are associated with resistance to infection in animal studies were here associated with an increased risk of infection in nursing infants.; The work presented in this thesis on infant parasitic GI nematode infection and breast milk cytokines suggest a direction for future research; building upon the observations made here to gain an understanding of factors around infant acquisition of parasitic GI nematode infection and the biology of breast milk cytokines---and how they relate to each other.