Molecular investigation of tick-borne pathogens in ixodid ticks infesting domestic animals (cattle and sheep) and small rodents (black rats) of Corsica, France

Although livestock farming (sheep, goats, pigs, and cattle) is an important economic activity in Corsica, a French Mediterranean island, knowledge about the tick fauna and microorganisms carried by them remains scarce. This study aimed to investigate the presence and perform molecular characterization of Anaplasmataceae, Rickettsia spp., and Borrelia burgdorferi sensu lato (sl) in tick species collected in Corsica. Ticks from cattle (Bos taurus), sheep (Ovis aries), and rodents (Rattus rattus) were collected from May to September 2016. DNA was purified from ticks, submitted to quantitative real-time polymerase chain reaction (qPCR) and sequenced for phylogenetic analysis. In total, 660 ticks were collected from 111 animals during the study. The most abundant collected tick species from cattle was Rhipicephalus bursa (n = 495; 84.5%), followed by Hyalomma marginatum (n = 91; 15.5%). Rhipicephalus bursa and Ixodes ricinus were the only tick species collected from sheep and rodents, respectively. Overall, Rickettsia was the most common pathogen group (n = 48; 24%) detected in ticks. Sequence analysis of partial gltA and ompA genes revealed the presence of Ri. aeschlimannii and Candidatus Ri. barbariae. Anaplasmataceae DNA was detected in eight (6%) of the 127 cattle pools and in one (2%) of the 61 R. bursa specimens collected from sheep. Sequence analysis of the rpoB gene revealed the presence of one Anaplasma species, A. marginale. Borrelia burgdorferi sl DNA was detected in one pool of H. marginatum collected from cattle and in two (15%) of the 13 I. ricinus pools collected from nine black rats. To our knowledge, this is the first report of the occurrence and molecular characterization of Candidatus Ri. barbariae, an emerging member of the Rickettsia group causing spotted fever, in Corsica. The detection of B. burgdorferi sl DNA, which was previously believed to be rare in Corsica, confirms the presence of this agent on the island.

Ticks and bacterial tick-borne pathogens in Piemonte region, Northwest Italy

A molecular screening for tick-borne pathogens was carried out in engorged and in questing ticks collected in Verbano Cusio Ossola county, Piemonte region, Italy. Engorged ticks were removed from wild and domestic animal hosts. The most abundant and common tick species in the area was Ixodes ricinus (192 adults, 907 nymphs). Few individuals of Ixodes hexagonus (15) and Rhipicephalus sanguineus (7) were found among the ticks removed from domestic animals (46 examined ticks). The presence of Rickettsia spp., Borrelia burgdorferi sensu latu, Francisella tularensis and Coxiella burnetii was evaluated by PCR and sequencing in 392 individuals of I. ricinus (adult and nymphal stages) and 22 individuals of the two other tick species. Five Borrelia species (i.e. B. burgdorferi sensu stricto, B. garinii, B. afzelii, B. valaisiana and B. lusitaniae), proved or suspected to cause clinical manifestations of Lyme disease in humans, showed 10.5 and 2.2% combined prevalence in questing and engorged I. ricinus, respectively. In addition, two species of rickettsiae (R. helvetica and R. monacensis) were identified and reported with 14.5 and 24.8% overall prevalence in questing and in engorged ticks. The prevalence of F. tularensis in the ticks collected on two wild ungulate species (Capreolus capreolus and Cervus elaphus) was 5.7%. This work provided further data and broadened our knowledge on bacterial pathogens present in ticks in Northwest Italy.