A new method to replace oral gavage for the study of Cryptosporidium infection in mice.

Oral gavage is a widely used method to infect mice with Cryptosporidium parvum (CP), the most common animal model of infection. Cryptosporidium spp. are worldwide distributed, gastrointestinal parasites that mainly cause diarrhea in humans and neonatal ruminants. CP is transmitted via the fecal-oral route, usually through contaminated water. In rodent models of Cryptosporidium infection, oral gavage is used as the route of infection. This method, while effective, induces a generalized stress response and requires specific skills and experience. Our aim was to replace oral gavage by a refined method using a mixture palatable to mice, where oocysts could be mixed in. A peanut butter gelatin mix (PBG) containing CP oocysts was developed and used for voluntary oral infection of mice. We were able to confirm CP infections in young interferon-gamma knock out mice by detecting oocyst shedding in feces, demonstrating that the PBG method successfully produced infections similar to those obtain through oral gavage, and could be used for other pathogens or as a method to deliver experimental therapeutics or other substances.