Chemoprophylaxis of Cryptosporidium parvum infection with paromomycin in kids: an immunological study

The anticryptosporidial activity of paromomycin, a natural antibiotic weakly absorbed when administered per os, was assessed in goat kids experimentally infected once via the oral route with 106 Cryptosporidium parvum oocysts. Paromomycin used prophylactically at a dose of 100 mg/kg of body weight per day from day21 to day 10 (day 0 was the inoculation day) prevented infection during the period of drug administration. A delayed low infection was suggested by an antibody rise, but the infection developed below the microscopic detection limits. This low parasite development induced a partial immunity in kids, which reacted immuno-logically to a challenge on day 21 without symptoms or detectable oocyst shedding. So, paromomycin is a good candidate for field trials because it is prophylactically effective against experimental C. parvum infection and well tolerated by animals. This drug would be useful in an adapted form as an anticryptosporidial agent for neonatal ruminants. In humans and cattle, primarily calves, lambs, and kids, cryptosporidiosis is a serious enteric disease caused by the coccidial protozoan parasite Cryptosporidium parvum, and it results in diarrhea, dehydration, weight loss, and sometimes death. C. parvum was detected in a goat kid in 1981 (11), bu