The role of chewing lice (Phthiraptera: Philopteridae) as intermediate hosts in the transmission ofHymenolepis microps(Cestoda: Cyclophyllidea) from the willow ptarmiganLagopus lagopus(Aves: Tetraonidae)

Abstract

The cestode Hymenolepis microps is an intestinal parasite of tetraonid birds, including the willow ptarmigan (Lagopus lagopus). This parasite is able to maintain a high prevalence and intensity throughout the year, even in a subarctic environment in bird populations with relatively low host densities, indicating effective transmission routes. Willow ptarmigan consume mainly vegetal material and active consumption of invertebrates is confined to the first two or three weeks of life. Ptarmigan are infected by different species of ectoparasites, of which two species of feather lice, Lagopoecus affinis and Goniodes lagopi, are the most abundant. In this study, we explored the hypothesis that feather lice may be suitable intermediate hosts for H. microps. We applied histological techniques and light microscopy to investigate lice for the presence of larval cestode stages (cysticercoids). We found 12 cysticercoid-like structures inside chewing lice collected on L. lagopus hosts harbouring H. microps. In addition, a polymerase chain reaction (PCR) screening of Ischnocera lice DNA, targeting the 18S rRNA gene of the cestode, showed positive results for two different short fragments of the 18S rRNA gene of H. microps which were sequenced from lice collected on birds. Both independent lines of evidence support the hypothesis that Ischnocera lice might be suitable intermediate hosts in the life cycle of H. microps in L. lagopus.

Phylogeny of hymenolepidids (Cestoda: Cyclophyllidea) from mammals: sequences of 18S rRNA and COI genes confirm major clades revealed by the 28S rRNA analyses

“…An analysis using Basic Local Alignment Search Tool (BLAST analysis, see ) was applied for comparison and possible identification with sequences available in GenBank for the family Hymenolepididae. For phylogenetic analyses, we used published sequences of 18S rRNA gene (table 2) and COI gene (table 3) from several previous studies (Littlewood & Olson, 2001; Olson et al ., 2001, 2003; Littlewood et al ., 2008; Guo, 2016; Nkouawa et al ., 2016; Zhao et al ., 2016; Pistone et al ., 2017; Dimitrova et al ., 2019). GenBank sequences with less than 90% length coverage compared to our dataset were excluded.…”

“…The newly obtained 12 18S rRNA sequences and 12 COI sequences (table 1) were manually edited and then aligned using MEGA software, version 7.0 (Kumar et al, 2016) and Olson et al, 2001Olson et al, , 2003Littlewood et al, 2008;Guo, 2016;Nkouawa et al, 2016;Zhao et al, 2016;Pistone et al, 2017;Dimitrova et al, 2019). GenBank sequences with less than 90% a The identification of this sample from the Korean Peninsula requires further confirmation by morphological and molecular studies, since the original description of Hymenolepis hibernia is from Apodemus sylvaticus from Northern Ireland (Montgomery et al, 1987).…”

“…a The generic allocation of this species is uncertain Pistone et al (2017). mentioned it as a member of Hymenolepis; this genus currently includes mammalian cestodes only (e.g Binkienė et al, 2019).…”

Anti-parasite behaviour of birds

“…Although preening is an effective means of combating ectoparasites, it has been co-opted as a transmission pathway by other parasites. Ectoparasites like lice and fleas are intermediate hosts of parasitic helminths [40][41][42][43]. These helminths are transmitted to avian hosts when the birds ingest ectoparasites during preening [42].…”

“…For example, filarioid nematodes (Eulimdana spp.) infecting marbled godwits (Limosa fedoa) and whimbrels (Numenius phaeopus), as well as tapeworms (Hymenolepis microps) infecting willow ptarmigans (Lagopus lagopus), can all be transmitted through the ingestion of infected feather lice [42][43][44]. Only a handful of studies have documented this mode of transmission; however, it is likely that other undiscovered parasites exploit this pathway.…”