Efficacy of injectable toltrazuril-iron combination product and oral toltrazuril against early experimental infection of suckling piglets with Cystoisospora suis

Abstract

Background Toltrazuril is frequently administered for the metaphylactic control of piglet cystoisosporosis. In a previous study, the efficacy of parenteral toltrazuril (45 mg/piglet, Group Forceris®) applied on the 2nd day of life (dol), and of oral toltrazuril (20 mg/kg of body weight, Group Baycox®) applied on the 4th dol was evaluated in an experimental model with Cystoisospora suis infection on the 3rd dol (late infection, LI). In a follow-up study, efficacy and safety were evaluated against infections with C. suis on the 1st dol (early infection, EI). Parameters included oocyst excretion and faecal consistency, body weight development, bacteriological examinations and animal health. Results All control piglets ( n = 12) shed oocysts and had diarrhoea, while parasite excretion was completely suppressed in both treatment groups ( n = 13 each) and diarrhoea was reduced to a single animal (Forceris® group), resulting in significant differences for these parameters between the treated groups and the controls without significant differences among the treatment groups. No treatment-related adverse events were noted. Body weight gain was reduced in the control group during the acute phase of infection, resulting in significantly lower body weight on the 15th dol. Sows and piglets shed high numbers of Escherichia coli . Clostridium perfringens type A was only detected in low amounts in pooled litter samples. In comparison to the LI study oocyst shedding was more intense in the control animals in EI, while diarrhea was more frequent in LI. In both infection models a high efficacy of toltrazuril in the control of parasitological and clinical outcomes of experimental C. suis infection could be demonstrated. Since in the LI study high numbers of Cl. perfringens type A were detected, it is hypothesized that colonization with these opportunistic pathogens has synergistic effects with C. suis and may explain variable clinical outcomes in untreated animals as well as the sporadic occurrence of diarrhea in toltrazuril-treated piglets. Conclusions Parenteral and oral toltrazuril administered on the 2nd or 4th dol is safe and effective against experimental infections with C. suis on the 1st to 3rd dol. The clinical outcome of experimental infections seems influenced by bacterial coinfections.

Shifts in the Fecal Microbial Community of Cystoisospora suis Infected Piglets in Response to Toltrazuril

“…Parasite propagation and study design, including experimental infection and treatment, were previously described (Joachim et al, 2019) with additional fecal samplings for microbiota analysis. In brief, 38 conventionally raised piglets (Landrace × Large White) from three crossbred sows were randomly allocated to three treatment groups.…”

“…Impaired intestinal homeostasis and slow regeneration of the intestinal epithelium in infected piglets lead to significant reductions in body weight gain, most likely due to reduced nutrient absorption (Mundt et al, 2003(Mundt et al, , 2006Joachim and Mundt, 2011). The disease is effectively controlled by oral or parenteral administration of a single dose of the triazinone toltrazuril during the developmental phase of C. suis in the host (Mundt et al, 2006;Joachim et al, 2018cJoachim et al, , 2019. The exact mode of action of toltrazuril is not known but it has been suggested that toltrazuril interferes with nuclear division and mitochondrial activity in coccidian parasites (Harder and Haberkorn, 1989).…”

The fecal microbiota evolves differently in piglets experimentally infected with Cystoisospora suis that are treated with toltrazuril

“…Oocyst excretion is a primary parameter to estimate the intensity and clinical presentation of C. suis infection [23]. Detailed results of the clinical and parasitological outcome of experimental infections of the involved animals have been published previously [7]. Briefly, three groups of piglets (n=11-13 animals/group) were used.…”

“…Parasite propagation and study design, including experimental infection and treatment, were previously described [7] with additional fecal samplings for microbiota analysis. In brief, 38 conventionally raised piglets (Landrace x Large White) from three crossbred sows were randomly allocated to three treatment groups.…”

“…Impaired intestinal homeostasis and slow regeneration of the intestinal epithelium in infected piglets lead to significant reductions in body weight gain, most likely due to reduced nutrient absorption [4][5][6]. The disease is effectively controlled by oral or parenteral administration of a single dose of the triazinone toltrazuril during the developmental phase of C. suis in the host [5,7,8].…”