Protection against infection with Giardia lamblia by breast-feeding in a cohort of Mexican infants.
To determine whether breast-feeding protects infants against symptomatic and asymptomatic infection by Giardia lamblia, we followed 197 infants in a poor area of Mexico City from birth to 18 months of age; symptoms and feeding status were recorded weekly. Stool specimens were collected every 1 to 2 weeks and tested for Giardia by enzyme-linked immunosorbent assay. A mean of 1.0 Giardia infection per child-year was detected; 94 infants had a total of 139 infections; 17% of infections were symptomatic. Ninety-one percent of infants were breast fed from birth and 38% were breast fed at 1 year of age. Lack of breast-feeding was a significant risk factor for first Giardia infection at all ages. The adjusted incidence rate ratio for first Giardia infection for none versus complete breast-feeding was 5.0 (confidence interval (CI) 1.5 to 16.9; p = 0.009), and for none versus any breast-feeding, 1.8 (CI 1.1 to 2.8; p = 0.013). Symptomatic Giardia infection was also associated with lack of breast-feeding (none vs any: incidence rate ratio = 2.5; CI 0.9 to 6.8; p = 0.077), but breast-feeding did not protect against chronic carriage of Giardia. Other significant risk factors for Giardia infection were presence of animals in the household (p = 0.005) and the use of water or nonmilk liquid for infant feedings (p = 0.035). We conclude that breast-feeding protects infants against Giardia by mechanisms that include preventing the establishment of infection.
Morrow
A L
AL
Department of Pediatrics, University of Texas Medical School, Houston.
Reves
R R
RR
West
M S
MS
Guerrero
M L
ML
Ruiz-Palacios
G M
GM
Pickering
L K
LK
D000818:Animals; D001942:Breast Feeding; D015331:Cohort Studies; D005243:Feces / Q000469:parasitology; D005260:Female; D005500:Follow-Up Studies; D016829:Giardia lamblia / Q000302:isolation & purification; D005873:Giardiasis / Q000453:epidemiology / Q000469:parasitology / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008800:Mexico; D011446:Prospective Studies; D012307:Risk Factors