Analysis of Dipylidium caninum tapeworms from dogs and cats, or their respective fleas - Part 2. Distinct canine and feline host association with two different Dipylidium caninum genotypes.

Frédéric Beugnet,Dionne Crafford,Christa de Vos,Josephus Fourie,Michel Labuschagne

doi:10.1051/parasite/2018029

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.

Highlights

This paper reports on an in vivo experimental infection study, designed to investigate potential host association with reference to the canine and feline D. caninum genotypes [29]
Infections with the canine D. caninum genotype were first observed in all three dogs from Week 5 to 7, with observed infections persisting throughout the study period, while infection with the feline genotype was not observed in all three dogs during that period
The molecular characterization of D. caninum isolates collected from dogs, cats, and in infected fleas collected either from dogs or cats enabled the identification of two distinct genotypes that clearly differ from each other [29]

Summary

Introduction

Dipylidium caninum sensu lato is an important cestode parasite with a worldwide distribution, as is evident from surveys performed in wild canids and felids, domestic cats, domestic dogs, or concurrent surveys assessing both domestic cats and dogs [1,3,4,6,8,9,10,11,13,14,15,16,17,18,19,21,25,26,28,30, 32,34,35,36,37,40,41,43,44,45,46,47,48] Apart from infecting both canids and felids, this cestode may occasionally infect humans [2,24,42]. It develops to an adult tapeworm, with shed proglottids visible in faeces from between 17 and 19 days after infection [22,23]

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