Analysis ofDipylidium caninumtapeworms from dogs and cats, or their respective fleas

Abstract

Initial investigations suggested the existence of two distinct genotypes of Dipylidium caninum from infected cat fleas (Ctenocephalides felis). One genotype was found almost always (> 95%) in fleas collected from, and proglottids shed by, domestic dogs. The other was found almost always (> 95%) in fleas collected from, and proglottids shed by, domestic cats. Molecular investigations (Part 1, in this journal) confirmed the presence of two distinct genotypes. Due to the apparent host association observed, these were referred to as the “D. caninum canine genotype” and the “D. caninum feline genotype”. The current article reports on an in vivo experimental infection study assessing the host-parasite interaction for each genotype. Mixed infections with the two genotypes in both dogs and cats were conducted. The specific genotyping of proglottids allowed us to assess the specific prepatent periods, prolificity, and longevity of each genotype in dogs versus cats. The possible hybridisation was also studied through molecular evaluation of the proglottids expelled by infected dogs and cats. Results demonstrate a clear distinct host interaction. The canine D. caninum genotype occurred at a higher frequency in dogs, with a shorter prepatent period and a longer lifespan; and the feline genotype occurred at a higher frequency in cats, with a shorter prepatent period and a longer lifespan. The absence of any hybrids in the mixed infections of both dogs and cats confirm the hypothesis of two distinct genotypes, suggesting the possibility of two distinct species within Dipylidium caninum.

Analysis of Dipylidium caninum tapeworms from dogs and cats, or their respective fleas

“…A comparison of biological development and host preference should confirm the genetic observations (Beugnet et al, 2018, [ 4 ]). The genetic differences observed in this analysis, which show a greater distance to what is known between different species of Taenia or Echinococcus , make it possible to suggest the existence of two distinct Dipylidium species, which will have to be confirmed or disproved.…”

“…The hydrolysis probe genotyping assays were also able to discriminate between homozygous for the “canine genotype”, homozygous for the “feline genotype” and an artificial heterozygous mix of DNA from both genotypes. This technique could serve to identify the possibility or not of hybridization between the two genotypes in definitive hosts, as cats and dogs are often present together in a same household [ 4 ].…”

“…Nevertheless, a small proportion (from 2 to 10%) of D. caninum DNA extracted from cats or C. felis fleas collected from cats, or extracted from dogs or C. felis fleas collected from dogs, belong to the other genotype. The specificity therefore does not appear to be absolute and should be studied by experimental infections in both dogs and cats (Beugnet et al, 2018, Part 2, [ 4 ]). The common presence of both cats and dogs in the same households, being infested by the same fleas (i.e.…”

“…The objectives of this study were thus to develop the necessary assays for genotyping D. caninum DNA to discriminate between the two D. caninum genotypes. These comparisons allowed the identification and breeding of the two genotypes, in order to further evaluate their biological differences (see Beugnet et al, 2018, part 2, [ 4 ]).…”

Severe Concomitant Physaloptera sp., Dirofilaria immitis, Toxocara cati, Dipylidium caninum, Ancylostoma sp. and Taenia taeniaeformis Infection in a Cat

“…Cats acquire D. caninum infection through the ingestion of fleas infected with the larval stage (cysticercoid) of this cestode. Recent studies describe two different genotypes for this species of cestode, with different host associations in cats versus dogs involving a shorter prepatent period and longer lifespan depending on the final host species, while also suggesting the possible existence of two host associated Dipylidium species [ 13 , 14 ]. After ingestion of the infected flea by a cat, usually during grooming, there is a prepatent period of 34 days on average.…”