Serological Investigation on Encephalitozoon cuniculi in pet Rabbits in North-Central Italy

This study determined the seroprevalence of Encephalitozoon cuniculi in pet rabbits from north-central Italy and correlated it with data (age and clinical signs) obtained from private veterinary practitioners. During the period 2007 to 2010, 826 pet rabbit sera were collected and tested using carbon immunoassay. In total, 310 out of 826 rabbits (37.53%, 95% CI: 34.23 to 40.94) displayed clinical signs consistent with infection, whereas the remaining 516 animals presented for wellness examination or to be vaccinated. The results were analyzed according to age, serological status, and the presence or absence of clinical signs. Seropositive results were observed in 59.56% (95% CI: 56.12 to 62.92) of the examined animals. Seroprevalence in the clinically ill rabbits was 70.65% (95% CI: 65.18 to 75.59), much higher than in healthy animals, which showed a prevalence of 52.91% (95% CI: 48.5 to 57.27). Clinical signs were classified into 4 groups: nonvestibular neurologic signs, vestibular signs (including head tilt), renal failure, and ocular lesions. Odds of animals presenting with clinical disease signs were higher in seropositive rabbits (odds ratio = 2.14, 95% CI: 1.59 to 2.9), and this association was particularly true for vestibular signs (odds ratio = 4.1, 95% CI: 2.48 to 7.13). The prevalence values were different with regard to age, with a peak in 3- to 4-year-old animals. Average titers in both healthy and clinically ill rabbits at various ages were different; rabbits with overt disease signs had higher titers when very young (<3 months) and from 1 to 4 years of age. In conclusion, this study provides more precise indications of the prevalence of E. cuniculi in pet rabbits in Italy, underlying growing interest and concern among veterinarians and pet owners regarding this organism.