Unique genomic characteristics underlie the infectivity of divergent Cryptosporidium hominis subtypes to animals

Cryptosporidiosis is the leading waterborne disease in high-income countries and the second most common cause of severe diarrhea in children in low- and middle-income countries. C. hominis has traditionally been considered an anthroponotic species, distinct from the zoonotic C. parvum by its lack of infectivity in rodents. C. hominis was once thought to infect only humans, but has been increasingly reported in animals. To date, more than 10 C. hominis subtype families with host preference have been recognized. Several of these have recently been found in nonhuman primates (NHPs) and equine animals. The genetic differences between human-pathogenic animal-adapted C. hominis and the determinants of host adaptation are not yet clear. In the present study, we performed whole-genome sequencing of 14 NHP-adapted and 3 equine-adapted C. hominis isolates.