Molecular Detection and Characterization of Spotted Fever Group Rickettsiae in Taiwan

Abstract

Rickettsioses are emerging infectious diseases caused by rickettsiae in association with arthropods. We report the detection of spotted fever group rickettsiae (SFGR) in Taiwan using molecular methods. Phylogenetic analyses of the 17-kd protein and citrate synthase (gltA) genes showed that SFGR TwKM01 detected in Rhipicephalus haemaphysaloides ticks was most similar to Rickettsia rhipicephali. Three TwKM01 isolates were obtained from three individual R. haemaphysaloides ticks. Small, intracellular, coccobacillary bacteria were found in infected L929 cells using immunofluorescence antibody testing and transmission electron microscopy. Two other SFGRs, TwKM02 and TwKM03, identified in Leptotrombidium chigger mites, were closely related to R. australis and R. felis URRWXCal(2), respectively. The TwKM03 strain was also detected in Ixodes granulatus ticks and widely distributed in Hualien, Kinmen, and Lienchiang counties in Taiwan. The endonucleases MaeII and HhaI selected for restriction fragment length polymorphism analysis of the gltA and 17-kd polymerase chain reaction products, respectively, were useful for genotyping Rickettsia species TwKM01, TwKM02, TwKM03, and other SFGRs. Although their infectivity and pathogenicity for vertebrates are unknown, the finding of SFGRs raises the possibility that bacteria other than Orientia tsutsugamushi, Coxiella burnetii, and R. typhi may be involved in rickettsial diseases in Taiwan.

Rickettsia felis in Ctenocephalides felis felis from Five Geographic Regions of Brazil

“…1,2 Since then, the bacterium has been reported infecting a number of invertebrate species, including fleas, mosquitoes, ticks, mites, and booklice. [3][4][5][6][7][8] Despite an apparent broad host range, the majority of the literature reports of R. felis have been on fleas of the genus Ctenocephalides; namely, C. felis felis and Ctenocephalides canis collected from domestic dogs and cats. [9][10][11][12] In Brazil, R. felis was reported infecting Ctenocephalides fleas in the states of Sã o Paulo, Minas Gerais, and Rio de Janeiro, all in the Southeastern region of the country.…”

Molecular Confirmation of Rhipicephalus haemaphysaloides Infesting Ruminants in Wayanad, Kerala, India

“…Laboratory studies revealed their role in the transmission of Rickettsia (Hsu et al, 2011). Tsui et al, (2007) detected spotted fever group rickettsial organism in R. haemaphysaloides using molecular methods in Taiwan. Experimental transtadial transmission of Babesia microti through R. haemaphysaloides in southern China was also reported (Li et al, 2016).…”

Human Case ofRickettsia felisInfection, Taiwan

“…Although there are no known human cases of infections caused by spotted fever group (SFG) rickettsiae in Taiwan, novel strains of SFG rickettsiae have been isolated as recently described (6,7). In addition, evidence for R. felis infections in cat and cat fl ea populations has been identifi ed by using immunofl uorescence assay (IFA), PCR, and organism isolation (K.-H.Tsai et al, unpub.…”

“…We collected fl eas by using a kerosene lamp hung above a 45-cm diameter tray containing water (7). Captured fl eas were identifi ed using a dissecting microscope and standard morphologic keys, sorted into vials by species and locality, and preserved in 70% ethanol (7).…”

“…Captured fl eas were identifi ed using a dissecting microscope and standard morphologic keys, sorted into vials by species and locality, and preserved in 70% ethanol (7). Fleas were separated into 193 pools (2-5 fl eas per pool), triturated for 10 minutes; the resultant fl ea triturate was centrifuged at 3,000 rpm for 10 minutes to collect fl ea tissue.…”