The impact of oral contact and alloparenting on infant diarrhea in a hunter-gatherer society in Cameroon

Diarrhea is among the most common causes of death in children under five years of age. Infants are particularly at risk of ingesting pathogens directly or indirectly because of their frequent oral contact with a variety of objects. In hunter-gatherer societies, the widespread use of alloparenting, in which the infant is cared for by someone other than the biological parents, may play an important role in reducing the risk of infection from oral contact in infants. This study explored the relationship between infant oral contact behavior and diarrhea as well as the effects of alloparenting on infant oral contact behavior and diarrhea in hunter-gatherer societies. We conducted an interview on infant diarrhea and a 6-hour direct observation focused on oral contact and alloparenting of 6 infants (2–28 months) and 29 caregivers (≥4 years). During the observation period, the infants had frequent contact with objects with high risk of infection, with a median of 10.5 events (range, 0–49 events), and 50% (n = 3) had diarrhea. In addition, infants mainly ate with their hands or from the hands of their caregivers, and there was no hand-washing behavior before eating, suggesting that hand-feeding may increase the risk of transmission of pathogens. Our results also showed that the number of caregivers prevented diarrhea in infants. Furthermore, alloparenting of the unique child-rearing patterns of hunter-gatherers contributed to blocking the infants’ contact with objects with high risk of infection. These study findings suggest that alloparenting may play a significant role in reducing the risks of infant diarrhea and infection by oral contact behavior, even when the risk of transmission of pathogens through oral contact among infants may be high, such as in hunter-gatherer societies.