Comparative Efficacy of Fipronil, Ivermectin and Clove Oil (Eugenia caryophyllata) against Psoroptes cuniculi Mites in Rabbits (Oryctolagus cuniculus)

Psoroptes cuniculi is the most common and cosmopolitan mange mite that causes otitis and skin disease in the domestic rabbit (Oryctolagus cuniculus) which is a small mammal, belonging to family Leporidae and used as source of food, fur, wool, as well as pet and experimental animal. P. cuniculi is obligate, non-burrowing, astigmatid ectoparasite of family Psoroptidae (Colebrook and Wall 2004) which scatters more rapidly through farm rabbits (Swarnakar et al., 2014) and infests internal surface of the pinna and external ear canal which causes intense pruritus, encrustation (Macchioni et al., 2004), anorexia, emaciation and death in extreme cases. Stress and poor husbandry conditions are the major risk factors. As Psoroptes is very commonly encountered condition of rabbits presented at Pet Centre, the study was designed to evaluate comparative efficacies of conventional drugs with clove oil which is a promising herbal medicine against Psoroptes cuniculi, as no previous studies are documented in Pakistan.

Body weight
 
Body weight was recorded on days 0, 7, 14 and 21 in all 3 groups. In groups A and B statistical analysis revealed a significant gain of body weight from days 0-21 and days 0-14, respectively followed by non-significant decrease of body weight on day 21. In group C, there was no significant increase in body weight till day 7 followed by slight gain of body weight on days 7-21 (P>0.05) (Fig 3).


 
Feed intake
 
In groups A and B there was no significant increase (P>0.05) in feed intake during days 0-14 followed by a slight decrease in feed intake by day 21. In group C, there was no improvement in feed intake till day 21. Statistically groups A, B and C were significantly different from each other on the basis of level of feed intake (P>0.05) (Fig 4).


 
Body itch
 
All the rabbits in group A, B and C were showing signs of pruritus at the beginning of this study. In group A, severity of continuous body itch was reduced to minimal level on day 7 followed by complete recovery on day 21. Whereas, group B and C showed moderate recovery from pruritus during days 14-21(Fig 5).


 
Allergic response associated eosinophil count
 
In group A, B and C differential leukocyte count (DLC) revealed a significantly increased eosinophils count on day 0 prior to the initiation of treatment followed by initiation of gradual and statistically significant decrease of eosinophil count from days 7-21 in all three groups (p>0.05) (mean eosinophil count shown in Fig 6). The increase in eosinophil counts in the intial infection might be due to raised plasma histamine concentration resulting into release of eosinophils into circulation which tend to return to normal after treatment (Singla and Juyal 2000).



No relevant data on the use of ivermectin and fipronil spot on is available on rabbits. However, it has been successfully used through subcutaneous route against P. cunicili and Notoedres cati (Singla et al., 1996).  The present results of group A were in line with the study of Kalbe and Hansen (2012) who employed the single use of ivermectin spot-on in 10-20 kg dog as a single dose of 1.3mL to treat skin mite. Whereas, single dose of 0.67mL of fipronil spot on was used for dog weighing 2-10 kg for treating skin mites in dogs (Bonneau et al., 2010). Our results were in line for clove oil efficacy with the study of Fichi et al., (2007) in which the treatment with the essential oil cured all infected rabbits.

Results revealed that all 3 drugs were effective against P. cuniculi; but ivermectin led recovery was quicker than rest of the two drugs. All three groups were free of lesions and mites on day 21 of treatment.

The study was partially funded by Pet Centre, University of Veterinary and Animal Sciences, Lahore and confers no conflict of interest.