Rickettsial infection in ticks infesting wild birds from two eco-regions of Argentina

Abstract

Several tick-borne Rickettsia species are recognized human pathogens in Argentina. Here we evaluated rickettsial infection in ticks collected on passerine birds during 2011-2012 in two eco-regions of Argentina. The ticks were processed by molecular analysis through polymerase chain reaction (PCR) detection and DNA sequencing of fragments of two rickettsial genes, gltA and ompA. A total of 594 tick specimens (532 larvae and 62 nymphs), representing at least 4 species (Amblyomma tigrinum, Ixodes pararicinus, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris), were evaluated. At least one A. tigrinum larva, collected on Coryphospingus cucullatus in Chaco Seco, was infected with Rickettsia parkeri, whereas at least 12 larvae and 1 nymph of I. pararicinus, collected from Troglodytes aedon, Turdus amaurochalinus, Turdus rufiventris, C. cucullatus and Zonotrichia capensis, were infected with an undescribed Rickettsia agent, genetically related to several rickettsial endosymbionts of ticks of the Ixodes ricinus complex. R. parkeri is a recognized human pathogen in several American countries including Argentina, where a recent study incriminated A. tigrinum as the potential vector of R. parkeri to humans. Birds could play an important role in dispersing R. parkeri-infected A. tigrinum ticks. Additionally, we report for the first time a rickettsial agent infecting I. pararicinus ticks.Keywords: Rickettsia parkeri, endosymbiont, Amblyomma tigrinum, Ixodes pararicinus, passeriformes. ResumoAlgumas espécies de Rickettsia transmitidas por carrapatos são reconhecidos como patógenos humanos na Argentina. Este presente trabalho avaliou a infecção por Rickettsia em carrapatos coletados em aves passeriformes, durante 2011-2012, em duas ecorregiões da Argentina. Os carrapatos foram processados pela reação em cadeia da polimerase (PCR) e sequenciamento de DNA de dois genes de Rickettsia: gltA e ompA. Ao todo, 594 amostras de carrapatos (532 larvas e 62 ninfas), representando pelo menos 4 espécies (Amblyomma tigrinum, Ixodes pararicinus, Haemaphysalis juxtakochi, Haemaphysalis leporispalustris), foram avaliadas. Pelo menos uma larva de A. tigrinum, coletada de Coryphospingus cucullatus no Chaco Seco, estava infectada com Rickettsia parkeri, enquanto pelo menos 12 larvas e 1 ninfa de I. pararicinus, coletadas de Troglodytes aedon, Turdus amaurochalinus, Turdus rufiventris, C. cucullatus e Zonotrichia capensis estavam infectadas com Rickettsia sp., geneticamente relacionada a vários endossimbiontes riquetsiais de carrapatos do complexo Ixodes ricinus. R. parkeri é reconhecidamente um patógeno humano em alguns países americanos, incluindo a Argentina, onde um estudo recente incriminou A. tigrinum como um provável vetor. Aves poderiam desempenhar um papel importante na dispersão de carrapatos A. tigrinum infectados por R. parkeri. Em adição, relata-se pela primeira vez a infecção por Rickettsia em I. pararicinus.

Survey of bacterial and protozoan microorganisms in ticks collected from birds in the Atlantic Forest biome in Piraí municipality, Rio de Janeiro, Brazil</p >

“…Several studies involving ticks in birds have detected microorganisms in these arthropods (Ogrzewalska et al 2011; Flores et al 2016; Ogrzewalska et al 2016; Luz et al 2017; Pacheco et al 2019; Ciccutin et al 2019). Most of these studies have investigated bacteria of the genus Rickettsia .…”

“…Several studies have reported the detection of pathogens in ticks infesting birds (Hornok et al 2014; Flores et al 2016; Zeringotá et al 2017). Therefore, studies on tick species carried by wild birds, as well as the disease agents transmitted by them, in different ecosystems can help to understand their dispersion as possible vectors for disease transmission.…”