Parasitol Res (2013) 112:S33–S46 DOI 10.1007/s00436-013-3279-5 ECTOPARASITES Prophylactic Treatment of Flea-Infested Dogs with an Imidacloprid / Flumethrin Collar (Seresto®, Bayer) to Preempt Infection with Dipylidium caninum Josephus J Fourie1, Dionne Crafford1 (*), Ivan G Horak2,3, Dorothee Stanneck4 1 ClinVet International, P.O. Box 11186, Universitas, Bloemfontein, 9321, South Africa 2 Department of Zoology and Entomology, University of the Free State, Bloemfontein, 9301, South Africa 3 Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, 0110, South Africa 4 Bayer Animal Health GmbH, 51368 Leverkusen, Germany Corresponding author: Dionne Crafford * E-mail: [email protected] Abstract The objective of the study was to determine the sus- metacestodes. Prior to each post-treatment infesta- tained effectiveness of 10 % imidacloprid and 4.5 % tion the D. caninum infection rate for the fleas was flumethrin, incorporated in a slow-release matrix determined by microscopically examining 100 fleas collar, in preventing Dipylidium caninum infection for D. caninum metacestodes. The D. caninum in dogs after repeated laboratory infestations with prevalence in the fleas used for infestations ranged fleas infected with metacestodes of this tapeworm. from 23 % to 52 %. Medicated collars were fitted to Efficacy against infection with D. caninum was 8 of the dogs on study day 0. The weight of the IVP evaluated by infesting 16 dogs with cat fleas (Cteno- collars varied between 35.48 g and 38.48 g (aver- cephalides felis) on study days 7, 14, 21, 28, 35 and age 37.16 g), whilst animal weight varied between 42, from batches suitably infected with D. caninum 12.20 kg and 17.98 kg (treated group, n = 8, average S33 ECTOPARASITES 14.79 kg). Seven days later infestation of each of of veterinary and zoonotic importance, including the 16 dogs with 250 fleas commenced. Infestations three protozoan species and the metacestode stage continued at weekly intervals until Day 42 with of the dog and cat tapeworm, Dipylidium caninum efficacy against fleas evaluated 24 hours after each (Pugh 1987; de Avelar et al. 2007). infestation. From Days 21 to 74, infection of the Dogs and cats acquire infection with D. caninum by dogs with D. caninum was verified (daily examina- ingesting infected fleas, most often during groom- tion of faeces and cages for the presence of expelled ing. Infection of dogs and cats with D. caninum is proglottids). Calculation of prophylactic effective- a global phenomenon. The parasite is widely dis- ness of the collars in preventing infection with tributed in Italy (Oranto and Dantas-Torres 2010) D. caninum was based on the difference in geomet- and 38 of 63 adult dogs selected for an anthelmin- ric mean numbers of scoleces between groups at tic efficacy trial were infected (based on faecal necropsy on Day 75. Effective prevention of infec- examination for proglottids) (Genchi et al. 1990). tion with D. caninum was found to be 96.6 %. Effi- Dipylidium caninum was also the most common cacy of the collars against fleas was ≥ 99.9 % for the helminth parasite in 156 dogs examined (either duration of the assessment period. after treatment with arecoline hydrobromide or at Newly acquired infestations of fleas are rapidly necropsy) in Israel, with 97 of the dogs infected eliminated by the insecticidal components of the (Furth and El-On 1990). Twelve of 15 dogs belong- medicated collars over a period of several months. ing to an aboriginal community on the South coast In the event of fleas being infected with metaces- of New South Wales, Australia, were infected, with todes, infection with D. caninum can be prevented the intensity of infection ranging between 1 and in collared dogs, concurrently reducing the likeli- 65 tapeworms (Jenkins and Andrew 1993). In an hood of transmission to humans. anthelmintic study conducted on dogs in Texas, USA, 18 noticeably flea-infested dogs were also all infected with D. caninum based on faecal examina- Introduction tion (Craig et al. 1991). At necropsy, scoleces (num- bers ranging from 2 to 44) were recovered from all The cat flea,Ctenocephalides felis, infests both dogs but one of the 8 untreated control animals (Craig and cats, is widespread throughout most regions of et al. 1991). Examination of 55 stray cats in Iraq the world (Beaucournu and Ménier 1998; Ménier yielded a D. caninum infection prevalence of 64 % and Beaucournu 1999; Beck et al. 2006) and is con- (Al-Obaidi 2012). In Gauteng Province, South Afri- sidered to be one of the most important ectopar- ca, 27 of 69 dogs (belonging to a resource-limited asites of dogs and cats (de Avelar et al. 2007). community) were found to be infected at necropsy. Infestation often results in itching and scratch- The number of scoleces recovered varied between ing, often progressing to hair loss and skin lesions 1 and 288 (Minnaar and Krecek 2001). Boreham caused by continuous grooming in more sensitive and Boreham (1990) reviewed some of the litera- animals. The development of flea allergy dermati- ture prior to 1990 and list Australia, India, Iraq, tis provoked by the saliva of feeding fleas has also Jordan, Malaysia, Morocco, Nigeria, Pakistan, the been reported (Genchi et al. 2000). Consequently USA and Zambia as countries in which infection effective control of C. felis not only eliminates fleas, with D. caninum has been encountered in dogs. but also alleviates discomfort caused to its hosts. In The near global occurrence of D. caninum infec- addition, fleas are considered to be of considerable tion can be considered an indication of the extent importance as vectors of pathogens in many parts of the problem. of the world (Bitam et al. 2010). More specifically, It is generally accepted that infection with D. ca- C. felis plays host to a number of endosymbionts ninum produces few if any clinical signs in dogs S34 ECTOPARASITES Fig. 1 Dissected Ctenocephalides felis showing the inner organs and metacestodes of Dipylidium caninum (arrows) S35 ECTOPARASITES (Boreham and Boreham 1990). These may include family dog “more or less” frequently is not sufficient mild gastrointestinal signs and scratching (Mani to provide reliable long-term protection against and Maguire 2009). However, infection of pets is human exposure to infection. usually a cause of considerable distress and often Besides changes in human behaviour (Jithendran embarrassment to their owners (e.g. when a dog and Bhat 2001) to mitigate the risk of accidental drags its anus over an indoor carpet). More impor- ingestion of fleas, biological control measures such tantly, humans may also become infected with as nematophagous fungi that have an effect on this cestode (Chappell et al. 1990; Raitiere 1992). D. caninum eggs in the environment (and would Infections are most often diagnosed in small chil- hence forestall infection of fleas) may be a preventa- dren as they are generally in closer contact with tive option (Araujo et al. 2009). Both options, how- family pets (and hence the fleas that infest them) ever, pose logistical challenges and the last one is (Chappell et al. 1990; Raitiere 1992; Jithendran scarcely effective. According to Mani and Maguire and Bhat 2001) and because of their propensity for (2009): “Precautionary measures are necessary to pica (Mani and Maguire 2009), but adults can also prevent zoonotic transmission of pathogens while be infected (Adam et al. 2012). A stool passed by a keeping a pet. Routine and regular veterinary 6-month-old infant contained 13 intact tapeworms care of companion animal pets with appropriate and several short strands of proglottids on the day preventative medicine is extremely important for after treatment (Chappell et al. 1990). prevention of transmission”. Chemical control thus The most obvious recourse to reduce the risk of appears to be an unavoidable option and when infection with D. caninum in the human environ- directed at breaking the D. caninum life cycle, may ment is certainly regular deworming of dogs with be efficacious both against fleas and tapeworms. a praziquantel containing drug. However, the It is thus obvious that a formulation offering sus- required frequency of treatment may be underes- tained efficacy against fleas on dogs may aid great- timated by the dog owner, especially as the dog can ly in preventing the zoonotic transfer of parasites, be re-infected at any time after successful anthel- including D. caninum. mintic treatment by the ingestion of an infected Imidacloprid was introduced in 1996 and has flea. Accordingly, simply deworming the infected since become one of the most successful and Fig. 2 SEM photograph showing a closer view of a Fig. 3 SEM photograph showing the surface detail of a metacestode of Dipylidium caninum (bar = 50 μm, metacestode of Dipylidium caninum (bar = 5 μm) box indicating the area shown in Fig. 3) S36 ECTOPARASITES largest selling veterinary products for flea control Materials and methods (Schroeder et al. 2003). Due to the rapid mode of action of imidacloprid, it decreases flea feeding This parallel, group-designed, randomised, uni- periods and hence reduces the risk of transmission centre, controlled efficacy study was conducted in of flea-derived diseases (Mehlhorn et al. 2001). It South Africa and involved two groups of dogs each is often combined with actives such as permethrin comprising eight animals. Initially 20 mixed-breed (e.g. Mehlhorn et al. 2003) or moxidectin (Mehlhorn domestic dogs ranging in age from sub-adults to et al. 2005; Schmahl et al. 2007) to also provide effi- adults were enrolled in the study. These dogs had cacy against ticks, mites and nematodes. As such, not been treated with an acaricide, or insecticide, products containing imodacloprid were shown to or a compound with an insect growth-regulating be effective against C. felis on hosts as diverse as activity during the previous 12 weeks and were dogs (Epe et al.