A new study carried out to look at the efficacy of spinosad (Comfortis) in cats has shown that they can acquire a flea infestation even when kept in a controlled laboratory environment.
The study was conducted on a laboratory colony of 15 cats that had been kept strictly indoors for at least a year, four of which had presented to the dermatology clinics of the Small Animal Hospital of the Toulouse Veterinary School, two with miliary dermatitis lesions and two with symmetrical alopecia.
Further investigation revealed that despite these animals having been confined to quarters for so long, adult Ctenocephalides felis and flea dirt were found on coat brushing.
All the cats were then combed meticulously twice at the start of the study using an extra fine comb and fleas counted before being replaced on each cat. In total 60 fleas were counted. On the cats showing no lesions there was an average of 5.2 fleas per cat and on the cats exhibiting flea allergy dermatitis it was less than one. Two of these cats had no fleas on them, probably due to excessive grooming caused by pruritus.
Spinosad was found to be 100% effective, with no adult fleas found on any cat from day 15 of the study through to day 90.
The cats with skin lesions were assessed for pruritus levels using the SCORFAD system, an extent and severity scale for feline hypersensitivity dermatitis. The SCORFAD value rapidly decreased throughout the study and achieved 98% reduction by day 90. The skin lesions in the flea allergic cats completely resolved during this time without the use of any other flea control or the use of anti-inflammatory products on the cats.
Researchers Maria-Christine Cadiergues and Charline Pressanti from Toulouse Veterinary School also noted a greater level of palatability than previously reported in clinical trials and there were no side effects in any of the cats.
Reviewing the study, David Grant MBE BVetMed CertSAD FRCVS said: "This study confirms that indoor cats, even in a tightly controlled laboratory environment, can still acquire an infestation of fleas. These can be brought in on the clothes of owners of cats if they have been in the garden, for example, particularly in the summer.
"In addition, flea allergic cats may have few fleas on them due to excessive grooming caused by pruritus, and it is often very difficult to persuade owners of the diagnosis, even more so with indoor cats. This study provides precise data to support the above statement.
"This study also demonstrates that spinosad can be used as a stand-alone treatment for mild to moderate flea infestation in an indoor environment without the need for environmental insecticides or anti-inflammatory treatment of the cats. This would be a major consideration for many cat owners."
Reference
Marie-Christine Cadiergues and Charline Pressanti, "Efficacy of Spinosad Tablets Administered to a Colony of 15 Indoor Cats Naturally Infested with Fleas," ISRN Veterinary Science, vol. 2014, Article ID 484308, 4 pages, 2014.doi:10.1155/2014/484308