Rickettsia fells in Chile.
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ABSTRACT:
SUBMITTER: Labruna MB
PROVIDER: S-EPMC3375787 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND:Rickettsial diseases are considered important in public health due to their dispersal capacity determined by the particular characteristics of their reservoirs and/or vectors. Among the latter, fleas play an important role, since the vast majority of species parasitize wild and invasive rodents, so their detection is relevant to be able to monitor potential emerging diseases. The aim of this study was to detect, characterize, and compare Rickettsia spp. from the fleas of micromammals in areas with different human population densities in Chile. METHODS:The presence of Rickettsia spp. was evaluated by standard polymerase chain reaction (PCR) and sequencing in 1315 fleas collected from 1512 micromammals in 29 locations, with different human population densities in Chile. A generalized linear model (GLM) was used to identify the variables that may explain Rickettsia prevalence in fleas. RESULTS:DNA of Rickettsia spp. was identified in 13.2% (174 of 1315) of fleas tested. Fifteen flea species were found to be Rickettsia-positive. The prevalence of Rickettsia spp. was higher in winter, semi-arid region and natural areas, and the infection levels in fleas varied between species of flea. The prevalence of Rickettsia among flea species ranged between 0-35.1%. Areas of lower human density showed the highest prevalence of Rickettsia. The phylogenetic tree showed two well-differentiated clades with Rickettsia bellii positioned as basal in one clade. The second clade was subdivided into two subclades of species related to Rickettsia of the spotted fever group. CONCLUSIONS:To our knowledge, this is the first report of the occurrence and molecular characterization of Rickettsia spp. in 15 flea species of micromammals in Chile. In this study, fleas were detected carrying Rickettsia DNA with zoonotic potential, mainly in villages and natural areas of Chile. Considering that there are differences in the prevalence of Rickettsia in fleas associated with different factors, more investigations are needed to further understand the ecology of Rickettsia in fleas and their implications for human health.
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2008-06-04 | GSE8041 | GEO
Project description:A flea-borne rickettsia, previously referred to as ELB, has been implicated as a cause of human illness. Using sequence data obtained from a fragment of the citrate synthase gene, we compared ELB, Rickettsia australis, R. rickettsii, and R. akari with the louse-borne R. prowazekii. We tallied 24 base pair differences between ELB and R. prowazekii and 25 between R. rickettsii and R. prowazekii; there were 30 base pair differences between R. australis and R. prowazekii and 29 between R. akari and R. prowazekii. We observed 32 differences between Rickettsia typhi and ELB. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analyses of ELB, with typing sera against R. typhi indicate that ELB surface antigens are more closely related to the flea-borne R. typhi than to the mite-borne R. akari. On the basis of the results of citrate synthase gene sequence comparisons, as well as previous comparisons with 16S rRNA and 17-kDa-protein gene segments, we found that ELB is sufficiently genetically distinct from other rickettsiae to be designated a new species, Rickettsia felis.
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Project description:PCR amplification indicated the minimum infection rate of Rickettsia spp. was 0.66% in Haemaphysalis longicornis ticks collected from Shandong Province, China. Phylogenetic analysis based on the rrs, gltA, ompA, and ompB genes indicated that the ticks carried R. japonica, Candidatus Rickettsia longicornii, and a novel Rickettsia species related to R. canadensis.
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Project description:Comparison of gene expression between the virulent Rickettsia rickettsii R strain and avirulent Rickettsia rickettsii Iowa. Keywords: virulent vs avirulent Virulent Rickettsia rickettsii R strain in triplicate was compared to avirulent Rickettsia rickettsii Iowa in triplicate
2010-05-26 | E-GEOD-8041 | biostudies-arrayexpress
Project description:Using PCR, we screened 411 ticks from four genera collected in Russia and Kazakhstan for the presence of rickettsiae and ehrlichiae. In Russia, we detected "Rickettsia heilongjiangensis," Rickettsia sp. strain RpA4, and Ehrlichia muris. In Kazakhstan, we detected Rickettsia sp. strain RpA4 and a rickettsia closely related to Rickettsia aeschlimannii. These agents should be considered in a differential diagnosis of tick-borne infections in these areas.
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Project description:DNA of several spotted fever group rickettsiae was found in ticks in Israel. The findings include evidence for the existence of Rickettsia africae and Candidatus Rickettsia barbariae in ticks in Israel. The DNA of R. africae was detected in a Hyalomma detritum tick from a wild boar and DNA of C. Rickettsia barbariae was detected in Rhipicephalus turanicus and Rhipicephalus sanguineus collected from vegetation. The DNA of Rickettsia massiliae was found in Rh. sanguineus and Haemaphysalis erinacei, whereas DNA of Rickettsia sibirica mongolitimonae was detected in a Rhipicephalus (Boophilus) annulatus. Clinicians should be aware that diseases caused by a variety of rickettsiae previously thought to be present only in other countries outside of the Middle East may infect residents of Israel who have not necessarily traveled overseas. Furthermore, this study reveals again that the epidemiology of the spotted fever group rickettsiae may not only involve Rickettsia conorii but may include other rickettsiae.
| S-EPMC4015588 | biostudies-literature
Project description:One of the most important vectors of the Brazilian Spotted Fever, the tick Amblyomma aureolatum in Brazil was used in this study. We laboratorial controlled the infection of adult females of A. aureolatum with the virulent brazilian strain Taiacu of Rickettsia rickettsii. The group of ticks was divided into 2 testing groups, group 2 (G2) composed of adult females incubated at 35°C for 3 days that were not fed after molting to adults and group 3 (G3) composed of adult females fed on its favorite natural host, the dog (Canis familiaris) also for 3 days. Right after incubation or feeding, ticks were individually dissected and all internal organs were transferred to RNAlater® Solution (Life Technologies) until gDNA and total RNA simultaneously isolation. A total of 14 ticks of each group were analyzed in two biological replicates (7 ticks each). Dye-swap was also applied to construct the technical replicate of each biological sample
2013-12-01 | GSE44315 | GEO