Case description: 3 unrelated, densely populated, dynamic ferret populations with severe outbreaks of enteric coccidiosis were evaluated.
Clinical findings: In each outbreak, morbidity rate was high, there were an appreciable number of deaths, and ferrets of all ages were affected. Affected individuals had acute onset of diarrhea, and feces often contained frank or digested blood. Other clinical signs included dehydration, weakness, lethargy, and weight loss. Fecal examinations of affected ferrets revealed sporadic and inconsistent shedding of coccidial oocysts. Necropsy findings included moderate to marked atrophic enteritis associated with numerous intraepithelial and fewer extracellular coccidial life stages. Sporulated oocysts isolated from feces were consistent with Eimeria furonis. A PCR assay was performed on formalin-fixed, paraffin-embedded sections of intestine for the gene encoding the small subunit of rRNA yielded products with sequences identical to those described for E furonis.
Treatment and outcome: Supportive care and treatment with sulfadimethoxine over the course of these outbreaks was palliative, but long-term treatment was required and failed to completely eradicate infection as identified by the subsequent finding of oocysts in fecal samples.
Clinical relevance: Enteric coccidiosis due to infection with E furonis has typically been reported to be subclinical rather than to cause severe gastrointestinal disease in ferrets. This report indicated that infection with E furonis may have contributed to severe enteric disease with high morbidity and mortality rates in 3 densely populated, dynamic groups of ferrets. Furthermore, long-term treatment with anti-coccidials may be required in outbreak situations, but may be ineffectual in completely eradicating infection.