Rickettsia helvetica and R. monacensis infections in immature Ixodes ricinus ticks derived from sylvatic passerine birds in west-central Poland.

Beata Biernat,Joanna Stańczak,Jerzy Michalik,Bożena Sikora,Stella Cieniuch

doi:10.1007/s00436-016-5110-6

Beata Biernat, Joanna Stańczak + Show 3 more

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https://doi.org/10.1007/s00436-016-5110-6

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Abstract

The aim of this study was to assess the importance of forest passerine birds in spreading ixodid ticks infected with rickettsiae of spotted fever group (SFG) in sylvatic habitats in western Poland. In total, 834 immature Ixodes ricinus ticks were found on 64 birds of 11 species which were captured during the tick-questing season between May and September of 2006. Ground-foraging passerines hosted most of the ticks compared with arboreal species, and therefore, only the former group was included into a detailed analysis. Significant predominance of larvae over nymphs was observed (581 vs. 253, respectively). Blackbirds and song thrushes hosted 82 % (n = 681) of the ticks collected from all infested passerines. The overall prevalence range of SF rickettsiae (including Rickettsia helvetica and Rickettsia monacensis) in bird-derived ticks was 10.5–26.9 %, exceeding that in questing ticks, and in ticks feeding on rodents and deer reported earlier from the same study area. This high prevalence of infection in immature I. ricinus ticks feeding on passerine birds strongly implies that they are involved in the enzootic maintenance of spotted fever group rickettsiae in the tick vector populations occurring in sylvatic habitats.

Highlights

Birds, especially passerine migratory species, could be involved in carriage of microbial pathogens as biological reservoirs, when microorganisms multiply in their body, mechanical carriers, and hosts of epidemiologically important ixodid ticks (Hubálek 2004; Foti et al 2011; Falchi et al 2012)
In Europe, Ixodes ricinus ticks detached from their avian hosts were found to harbor tick-borne encephalitis virus (TBEV) (Waldenström et al 2007; Kazarina et al 2015), different genospecies of Borrelia burgdorferi sensu lato (Comstedt et al 2006; Poupon et al 2006; Michalik et al 2008; Heylen et al 2012), Anaplasma phagocytophilum (Paulauskas et al 2009; Mǎrcuţan et al 2014), spotted fever group Rickettsia spp. (Elfving et al 2010), Babesia spp. (Franke et al 2010b; Hasle et al 2011; Žėkienė et al 2011), and others (Hasle 2013; Lommano et al 2014; Berthová et al 2016)
We aimed to assess the prevalence of Rickettsia spp. in ticks removed from birds captured in the sylvatic areas of western Poland

Summary

Introduction

Especially passerine migratory species, could be involved in carriage of microbial pathogens as biological reservoirs, when microorganisms multiply in their body, mechanical carriers, and hosts of epidemiologically important ixodid ticks (Hubálek 2004; Foti et al 2011; Falchi et al 2012). In Poland, the only studies on the role of birds in ecology of tick-borne diseases were focused so far on Lyme borreliosis and A. phagocytophilum, the agent of granulocytic anaplasmosis (Gryczyńska et al 2004; Skoracki et al 2006; Michalik et al 2008). The results obtained validated the concept of some avian-associated genospecies within the B. burgdorferi s.l. complex and demonstrated that passerine birds, like tree pipit, dunnock, chaffinch, and thrush species (Turdus merula and Turdus philomelos), may support the circulation of B. garinii and B. valaisiana under natural conditions as a reservoir of spirochetes and carriers of infected ticks. We aimed to assess the prevalence of Rickettsia spp. in ticks removed from birds captured in the sylvatic areas of western Poland. This paper is a follow-up study to our previous investigation on the role of deer, rodents, and ticks feeding on them in the perpetuation of the spotted

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