Rickettsioses are re-emerging vector-borne zoonoses with a global distribution. Recently, Rickettsia sp. strain Atlantic rainforest has been associated with new human spotted-fever (SF) cases in Brazil, featuring particular clinical signs: eschar formation and lymphadenopathy. These cases have been associated with the tick species, Amblyomma ovale . From 2010 until 2015, the Brazilian Health Department confirmed 11 human SF cases in the Maciço de Baturité region, Ceará, Brazil. The present study reports the circulation of Rickettsia spp. in vectors from this entirely new endemic area for SF. A total of 1,727 ectoparasites were collected in this area from the environment, humans, and wild and domestic animals. Samples ( n = 887) were screened by polymerase chain reaction (PCR), targeting the glt A and omp A rickettsial genes. Sequencing and phylogenetic analyses of glt A gene amplicons were carried out for 13 samples positive for both screening PCRs. Fragments of glt A and omp A from three samples were cloned, sequenced, and analyzed further. A. ovale and Rhipicephalus sanguineus specimens, collected from dogs, were found to be infected with Rickettsia sp. str. Atlantic rainforest, suggesting the importance of dogs in the epidemic cycle. Candidatus Rickettsia andeanae, Rickettsia felis , and Rickettsia bellii were also found infecting ticks and fleas in five municipalities, demonstrating the broad diversity of rickettsiae in circulation in the studied area. This study reports, for the first time, evidence of infection with Rickettsia sp. strain Atlantic rainforest in A. ovale and R. sanguineus in Ceará, and Ca. R. andeanae in an Atlantic rainforest environment of Brazil.

Amblyomma nodosum ticks were collected from one collared anteater (Tamandua tetradactyla) in the Caatinga biome, Brazil. From one sample, we isolated a Rickettsia sp. that was phylogenetically close to Rickettsia sp. strain NOD, with 99.9, 100.0, and 99.8% identity for gltA, htrA, and ompA genes, respectively.

Tick-borne rickettsioses (TBR) are caused by obligate, intracellular bacteria of the spotted-fever group (SFG) of the genus Rickettsia (Order Rickettsiales), transmitted by hard ticks. TBR are one of the oldest known vector-borne zoonoses and pose a threat to both human and animal health, as over the years, new SFG Rickettsia spp. have been reported worldwide with the potential to be human pathogens. In Portugal and Spain, the countries that constitute the Iberian Peninsula, reported TB rickettsiae causing human disease include Rickettsia conorii conorii, Rickettsia conorii israelensis, Rickettsia slovaca, Rickettsia raoultii, Candidatus Rickettsia rioja, Rickettsia sibirica mongolitimonae, and Rickettsia monacensis. An allochthonous case of TBR caused by Rickettsia massiliae, described in Spain, points to the need to monitor disease epidemiology, to predict risks of exposure and spread of disease, and taking into account globalization and climate changes. This review aims to provide up-to-date information on the status of TBR in the Iberian Peninsula, as well as to show the importance of a national and international collaborative epidemiology surveillance network, towards monitoring Rickettsia spp. circulation in both Portugal and Spain.

Bartonella spp. comprises emergent and re-emergent fastidious Gram-negative bacteria with worldwide distribution. Cats are the main reservoir hosts for Bartonella henselae and dogs represent opportunistic hosts for the bacteria. Even though ticks may also play a role in transmission, their competence as vectors for Bartonella spp. has not been totally understood. Considering only a few studies had a focus on screening Bartonella in animals, humans and ectoparasites in Portugal, this study aimed to address the molecular occurrence of Bartonella sp. in 123 stray cats, 25 stray dogs, 30 humans from Lisbon and 236 questing ticks within the country. Using a qPCR targeting the nuoG gene, it was possible to detect Bartonella sp. DNA on 20.32% of cat samples (25/123). From these positive samples, 13 sequences were characterized as B. henselae, 11 as B. clarridgeiae and 1 presented co-infection with both species. The absolute quantification of nuoGBartonella DNA in sampled cats ranged from 2.78 × 10 to 1.03 × 10⁵ copies/µL. The sampled dogs, humans and ticks were negative. These results showed that B. henselae and B. clarridgeiae are circulating in stray cats from Lisbon. Additional and more extended studies should be conducted to determine the impact of such infections on humans, particularly those in constant and direct contact with cats.

Neoehrlichia mikurensis is a new emerging tick-borne Gram-negative bacterium, belonging to the family Anaplasmataceae, the main vector of which in Europe is the tick Ixodes ricinus. N. mikurensis is responsible for neoehrlichiosis, occurring mostly in patients with underlying diseases. In the present study, a total of 348 I. ricinus and Dermacentor reticulatus ticks collected in north-eastern Poland were analyzed for the prevalence of N. mikurensis. A total of 140 questing ticks (124 of I. ricinus ticks and 16 D. reticulatus) collected with the flagging method and 208 ticks (105 and 103 I. ricinus and D. reticulatus, respectively) removed from dogs were selected for the study. cDNA (questing ticks) and total DNA (questing and feeding ticks) were analyzed by qPCR targeting the 16S rRNA gene of N. mikurensis. Positive samples were further analyzed by nested PCR and sequencing. The prevalence differed between ticks collected from vegetation (19.3%; 27/140) and ticks removed from dogs (6.7%; 14/208). The presence of the pathogen in questing and feeding D. reticulatus ticks was proven in Poland for the first time. In summary, our research showed that infections of ticks of both the most common tick species I. ricinus and D. reticulatus in north-eastern Poland are present and ticks collected from urban areas were more often infected than ticks from suburban and natural areas. The detection of N. mikurensis in I. ricinus and D. reticulatus ticks from north-eastern Poland indicates potential transmission risk for tick-bitten humans at this latitude.