Presence of Giardia lamblia in stools of six- to 18-month old asymptomatic Malawians is associated with children's growth failure

Aim: Despite high pathogen burden and malnutrition in low-income settings, knowledge on relationship between asymptomatic viral or parasitic infections, nutrition and growth is insufficient. We studied these relationships in a cohort of six-month-old Malawian infants. Methods: As part of a nutrient supplementation trial for 12 months, we documented disease symptoms of 840 participant daily and anthropometric measurements every three months. Stool specimens were collected every six months and analysed for Giardia lamblia, Cryptosporidium species and enterovirus, rotavirus, norovirus, parechovirus and rhinovirus using polymerase chain reaction (PCR). The prevalence of the microbes was compared to the children's linear growth and the dietary. Results: The prevalence of the microbes was similar in every intervention group. All age groups combined, children negative for G. lamblia had a mean standard deviation (SD) of −0.01 (0.49) change in length-for-age Z-score (LAZ), compared to −0.12 (0.045) among G. lamblia positive children (difference −0.10, 95% CI −0.21 to −0.00, p = 0.047). The LAZ change difference was also statistically significant (p = 0.042) at age of 18–21 months but not at the other time points. Conclusion: Asymptomatic G. lamblia infection was mainly associated with growth reduction in certain three-month periods. The result refers to the chronic nature of G. lamblia infection.