Prospective cohort study ofCryptosporidiuminfection and shedding in infants and their households

BackgroundCryptosporidium sppare responsible for significant diarrheal morbidity and mortality in under-five children. There is no vaccine, thus a focus on prevention is paramount. Prior studies suggest that person-to-person spread may be an important pathway for transmission to young children. Here we describe a longitudinal cohort study of 100 families with infants to determine rates of cryptosporidiosis within households during the COVID-19 pandemic.MethodsFamilies living in Mirpur, Bangladesh with one infant age 6-8 months were enrolled and followed with weekly illness survey and stool testing for Cryptosporidium for 8 months.ResultsFrom December 2020 to August 2021, 100 families were enrolled. Forty-four percent of index children, and 35% of siblings had at least oneCryptosporidiuminfection. Shedding ofCryptosporidiumoccurred for a mean of 19 days (sd 8.3 days) in index infants, 16.1 days (sd 11.6) in children 1-5 years, and 16.2 days (sd 12.8) in adults. A longer duration ofCryptosporidiumshedding was associated with growth faltering in infants. There was a spike inCryptosporidiumcases in May 2021, which coincided with a spike in SARS-CoV-2 cases in the region.ConclusionIn this intensive, longitudinal study ofCryptosporidiuminfection in families we found high rates of cryptosporidiosis in infants and children, and prolonged parasite shedding, especially among malnourished children. These data support that transmission within the household is an important route of exposure for young infants, and that treatment of non-diarrheal infection to interrupt person-to-person transmission within the home may be essential for preventing cryptosporidiosis in infants.summaryCryptosporidiosis is a leading cause of morbidity and mortality among children. We followed 100 families with infants living in Bangladesh and studied the incidence ofCryptosporidiuminfection. We found prolongedCryptosporidiumshedding in stool was common among infants and adults.