Seroepidemiological Study of Spotted Fever Group Rickettsiae and Identification of a Putative New Species, Rickesttsia sp. Da-1, in Gongliao, Northeast Taiwan

Abstract

Tick-borne spotted fever group (SFG) rickettsioses were neglected in Taiwan. The study reported a seroepidemiological survey of SFG rickettsiae in residents in Gongliao District, Northeast Taiwan. Blood samples were examined for antibodies against SFG rickettsiae by enzyme-linked immunosorbent assay and immunofluorescence assay. Risk factors were assessed using logistic regression. Ticks parasitizing dogs were collected within a 2 km radius from the houses of seropositive participants, and PCR was performed to detect possible tick-borne pathogens. Of 1108 participants, 75 (6.8%) had antibodies against SFG rickettsiae. Residents were more likely to be seropositive if they were older than 65 years, recruited by Dr. Enjoy’s Clinic, or resided in Jilin village. A total of 184 ticks including 5 species (Rhipicephalus sanguineus, Rhipicephalus haemaphysaloides, Dermacentor auratus, Haemaphysalis hystricis, Haemaphysalis ornithophila) were collected. Rickettsia spp. were detected in 6.5% (12/184) of ticks. Rickettsia sp. TwKM01 was found in 6 R. sanguineus and 4 R. haemaphysaloides; while Rickettsia sp. TwKM03 was identified in 1 R. sanguineus. Moreover, gene-based pairwise analysis indicated identification of a putative new species, Rickettsia sp. Da-1, in D. auratus. These findings provided evidence of SFG rickettsiae infection in ticks and suggested SFG rickettsiae exposure in the residents.

A novel Rickettsia, Candidatus Rickettsia takensis, and the first record of Candidatus Rickettsia laoensis in Dermacentor from Northwestern Thailand

“…Therefore, glt A on its own might not be enough to differentiate between closely related Rickettsia species. Consequently, the MLST of 17-kDa, glt A, 16S rRNA, omp A, omp B, and sca 4 were suggested as potentially helpful and appropriate for the reconstruction of the evolutionary relationship of diverse but closely related Rickettsia species, as documented in our results and previous reports 1 , 2 , 16 , 38 , 40 , 41 .…”

“…(2022) also reported Ca. R. laoensis infecting D. auratus in Taiwan, based on nucleotide sequences of four genes; glt A (MZ869826), omp A (MZ869827), omp B (MZ869829), and sca 4 (MZ869830) 41 . Taken together, these data suggest that Ca.…”

Surveillance of ticks on a tropical island with introduced ungulates

“…In Taiwan, numerous tick-borne pathogens have been detected in ticks and human patients, including Dabie bandavirus (Lin et al 2020), the Babesia microti protozoan (Shih et al 1997), and a wide range of bacterial organisms, such as Borrelia burgdorferi , Borrelia garinii , Borrelia afzelii (Chao et al 2010, 2011), Anaplasma phagocytophilum (Tsai et al 2019, Chang et al 2023), Ehrlichia chaffeensis (Peng et al 2019, Yen et al 2020), and several Rickettsia species (Kuo et al 2015, 2017, Yen et al 2021). Although ticks are frequently studied in Taiwan, most research has focused on ticks infesting dogs (e.g., Chao et al 2019) or rodents (e.g., Kuo et al 2011, 2015), with a few exceptions including studies on birds (Kuo et al 2017) or reptiles (e.g., Chao et al 2013, Kwak et al 2020).…”