Prevalence and diversity of spotted fever group Rickettsia species in ixodid ticks from domestic dogs in Chad, Africa.

Tick-borne pathogens in the genus Rickettsia are the causative agents of severe and potentially fatal spotted fever group (SFG) and typhus group diseases in dogs and humans. Climate, habitat, and land-use changes are impacting vector ranges, with expansions potentially resulting in novel pathogens being introduced into naïve locations. Despite the public health importance of SFG Rickettsia, there are relatively few data on the prevalence and diversity of rickettsial pathogens in sub-Saharan Africa. The aim of this study was to characterize the SFG Rickettsia prevalence and diversity in ixodid ticks (104 Amblyomma spp., 160 Rhipicephalus spp., and one Hyalomma truncatum) collected from domestic dogs in Chad, Africa. Ticks were screened for Rickettsia spp. using a nested PCR targeting the 17-kDa gene. Species identification was through bidirectional Sanger sequencing of the 17-kDa, ompA, ompB, and/or gltA gene targets. A total of 43.3 % (115/265) ticks were positive for Rickettsia spp. and six Rickettsia species were identified: R. africae, R. massiliae, R. conorii, R. felis, R. monacensis and Candidatus Rickettsia muridii. Seven additional samples were positive for Rickettsia of undetermined species. Rickettsia africae, an important zoonotic pathogen, was found in 81 % (79/97) of A. variegatum and 29 % (2/7) of an A. marmoreum complex species, a group that infests a wide range of birds and mammals, including humans. Finally, we detected a high diversity of Rickettsia spp., most of which were zoonotic, in Rh. muhsamae. Collectively these data indicate there is a risk of rickettsiosis in Chad and further studies on ticks and rickettsial pathogens in this region are warranted.

Osip S ，Friedman M ，Haynes E ，Coker SM ，Bryan Ii JA ，Sidouin M ，Ouakou PT ，Ngandolo BNR ，Cleveland CA ，Yabsley MJ ... -  《-》

Dog ectoparasites as sentinels for pathogenic Rickettsia and Bartonella in rural Guatemala.

Fleas and ticks serve as vectors of multiple pathogens in the genera Rickettsia and Bartonella that cause diseases in humans and other animals. Although human rickettsiosis and bartonellosis have been reported in all countries in Central America, limited research has been conducted to investigate the natural cycles of flea- and tick-borne rickettsiosis and bartonellosis, especially in Guatemala. We evaluated dog parasites as sentinels for zoonotic disease risk in rural Guatemala by sampling ticks and fleas from dogs, which were then identified and individually screened for Rickettsia and Bartonella. A total of 77 households were surveyed and 80.5 % of them had dogs. Overall, 133 dogs were examined for fleas and ticks, of which 68.4 % had fleas and 35.3 % had ticks. A total of 433 fleas and 181 ticks were collected from the infested dogs, with an additional 33 ticks collected from house walls. Three flea species were identified: Ctenocephalides felis (70.0 %), Echidnophaga gallinacea (11.8 %), and Pulex sp. (17.8 %). Among the collected ticks, 97 % were identified as Rhipicephalus sanguineus sensu lato with the rest being Amblyomma cajennense, A. auricularium, and A. ovale. Rickettsia felis were detected in six C. felis, in one Pulex sp., and in two R. sanguineus sensu lato, while Candidatus R. senegalensis was detected in one C. felis. Bartonella was detected only in fleas, including three Pulex sp. infected with B. vinsonii subsp. berkhoffii, B. henselae, and Bartonella sp., respectively, and 11 C. felis infected with B. henselae. This study reports Candidatus R. senegalensis and B. vinsonii subsp. berkhoffii in Guatemala for the first time, and indicates the potential risk of human and dog exposure to Rickettsia and Bartonella species. These results show that dogs provide critical information relevant to managing human potential exposure to flea- and tick-borne pathogens in rural Guatemala. This approach can potentially be expanded to other regions in Central America where domestic dogs are abundant and suffer from ectoparasite infestation.

Tian Y ，Juarez JG ，Moller-Vasquez AM ，Granados-Presa M ，Ferreira FC ，Pennington PM ，Padilla N ，Hamer GL ，Hamer SA ... -  《-》

Genetic diversity of Rickettsia africae isolates from Amblyomma hebraeum and blood from cattle in the Eastern Cape province of South Africa.

Pillay AD ，Mukaratirwa S 《-》

Short Communication: Anaplasma phagocytophilum and Babesia spp. in ixodid ticks infesting red foxes (Vulpes vulpes) in Great Britain.

Red foxes (Vulpes vulpes) are found throughout the United Kingdom (UK), and can reach high population densities in urban areas. They are often infested with ticks which may carry tick-borne pathogens, leading to a risk of transmission to domestic animals and humans. This study investigated the prevalence of tick-borne pathogens in ticks sourced from red fox carcasses across Great Britain between 2018 and 2022. Tick species were identified using morphological keys and molecular barcoding, followed by specific pathogen testing using PCR. In total, 227 ticks were collected from 93 foxes. Pooling (n = 2) was undertaken for unengorged nymphs from the same tick species and fox host, with 203 homogenates tested in total (24 pools and 179 individual ticks). Ixodes hexagonus was the most abundant tick species sampled (73 %), of which 59 % were nymphs and 41 % were females. Less common were Ixodes ricinus (12 %) and Ixodes canisuga (15 %), the majority of which were females (73 % and 91 %, respectively). One Ixodes sp. larva was identified. Babesia DNA was identified in seven individual ticks and once in pooled ticks (n = 2); seven detections were in I. hexagonus and one in I. canisuga, with an overall detection rate of 7 % (95 % CI: 6 - 8 %). Sequence analysis confirmed that all Babesia detections in I. hexagonus were Babesia vulpes, with detection of Babesia Badger Type A in I. canisuga. Screening for Anaplasma phagocytophilum DNA through amplification of the msp2 gene yielded an overall detection rate of 4 % (detected in I. hexagonus only). Louping ill virus was not detected by qRT-PCR in any tick RNA tested. The majority of pathogen detections were in ticks from red foxes in rural areas of the UK, although a small number of Babesia detections were in ticks collected from semi-rural or urban red foxes. Additionally, B. vulpes was detected in GB red fox tissues, suggesting a potential role as a reservoir host. This study confirms the detection of tick-borne pathogens in ticks infesting UK red foxes and highlights the involvement of GB tick species in animal or human disease transmission.

Mansfield KL ，González E ，McKay S ，Apaa T ，Kent AJ ，Cropper P ，Berry N ，Hernández-Triana LM ，Johnson N ... -  《-》

Wide spectrum of tick-borne pathogens in juvenile Ixodes ricinus collected from autumn-migrating birds in the Vistula River Valley, Poland.

Migratory birds serve as potential hosts for ticks and can be reservoirs of tick-borne pathogens (TBPs). The aim of our study was to investigate the prevalence of TBPs in juvenile Ixodes ricinus collected from Erithacus rubecula, Turdus merula, and Turdus philomelos passing through the Vistula River Valley, Poland - one of the most important European north-south routes for migratory birds. To detect TBPs in collected ticks we used a high-throughput microfluidic real-time PCR method. In addition, we performed a phylogenetic analysis of Borreliella garinii flaB and Rickettsia helvetica ompB sequences, considering haplotype diversity through a Median Joining Network. Our results showed a high prevalence and wide spectrum of TBPs in both larvae and nymphs of I. ricinus. Overall, including co-infections, 47.41% of the tested tick specimens were infected with at least one TBP. Borreliaceae spirochetes were detected in ticks collected from all examined bird species. Ticks (larvae and nymphs) collected from T. merula showed the highest prevalence of Bo. garinii (33.33%), Bo. burgdorferi s.s. (7.69%) and Borrelia miyamotoi (2.56%), while the highest number of ticks infected with Bo. valaisiana were collected from T. philomelos (8.11%). In turn, the highest prevalence of R. helvetica (20.00%) was observed in ticks collected from E. rubecula. Additionally, infections with A. phagocytophilum (5.00%), Ehrlichia spp. (2.50%), Ba. divergens (2.50%) and Ba. venatorum (2.50%) were only confirmed in ticks collected from this bird species. The phylogenetic analysis of Bo. garinii revealed that the detected haplotype circulates widely across various hosts and is geographically widespread, while the haplotype of R. helvetica is mainly detected in ticks in Central Europe. Ticks carried by T. merula, T. philomelos, and E. rubecula migrating along the Vistula River Valley, Poland are characterized by a high prevalence and a wide spectrum of detected TBPs. Tested ticks carry widespread strains of Bo. garinii, in contrast to R. helvetica, which is mainly found in Central Europe. Therefore, further research on the possible role of birds as reservoirs of TBPs is needed.

Kulisz J ，Zając Z ，Foucault-Simonin A ，Woźniak A ，Filipiuk M ，Kloskowski J ，Rudolf R ，Corduneanu A ，Bartosik K ，Moutailler S ，Cabezas-Cruz A ... -  《BMC Veterinary Research》