Efficacy of an oral solution of paromomycin for the treatment of newborn calves with cryptosporidiosis in European farms

Two independent multicenter European field studies involving 44 dairy and suckling beef farms were carried out following a parallel, controlled, randomized, blinded design. Farms were selected based on recent history of C. parvum infection in calves, absence of concomitant preventive treatments against cryptosporidiosis, absence of recent or current BVD infections, and no re- cent history of diarrhoea due to coronavirus, E. coli and rotavirus, or alternatively dedicated vaccination. To be enrolled, newborn calves were required to meet the following criteria: age between 3-14 days on first treatment, faecal score ≥ 2 (loose to watery), negative rapid test for E. coli, coronavirus, rotavirus, and positive rapid test for C. parvum. Any calf that presented with diarrhoea for > 24 hours or that has been previously exposed to antibiotics, parasiticides or probiotics was excluded. Animals were randomly allocated to two treatment groups. Calves in group 1 received 150 mg paromomycin sulfate/kg b.w. [Gabbrovet Multi®, Ceva], once daily, for 5 days by oral route while calves in group 2 were orally administered 100 µg halofuginone/kg b.w. [Halocur®, MSD], once daily, for 7 days. Several clinical and parasitological parameters were monitored at fixed times during the 21 days of the study: faecal score (0-3), general health observation (0-3), hydration score (0-3), and oocyst counts (number of oocysts per gram of dry faeces). Percentages of calves clinically cured on day 8 was considered a pivotal outcome to evaluate the efficacy of the interventions. Calves were considered cured if for a minimum of two consecutive observations all their clinical scores were equal to zero, to the exception of faecal score that could be equal to zero or 1. Other criteria such as time to clinical cure, number of days when calves were asymptomatic or considered in relapse from Day 0 to Day 8 and the parasitological cure at day 7 (oocyst count = 0) were also assessed. Safety (adverse events, serious adverse events) was evaluated at any time during the studies. The statistical unit was the calf.

In these European field studies, daily oral treatment with 150 mg/kg of paromomycin (Gabbrovet Multi®) for 5 days was found safe and highly effective to cure sick dairy and beef calves with cryptosporidiosis and to control their oocyst burden. In addition, this treatment regimen was found superior to treatment based on halofuginone.