Genetic variants of Orientia tsutsugamushi in domestic rodents, northern China.
Ontology highlight
ABSTRACT:
SUBMITTER: Zhang M
PROVIDER: S-EPMC3713967 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:BackgroundScrub typhus is endemic to a 13,000,000-km² area of the Asia-Pacific region, and causes an annual incidence of 1 million people. The mortality rate of scrub typhus ranges from 6.1% to 25% in Southeast Asia. Natural infection of Orientia tsutsugamushi has been identified in domestic rodents in Shandong Province. However, infestation of chiggers and ticks on the domestic rodents and prevalence and genotypes of O. tsutsugamushi in these Acarina remain unclear.MethodsDuring September 2010 to March 2012, 3134 chiggers and 89 ticks were collected from domestic rodents captured in three counties of Shandong Province. We amplified and sequenced the 56-kDa type-specific antigen gene of O. tsutsugamushi from DNA samples of these Acarina and designated to genotype according to sequence analysis.ResultsOverall, the infestation rate of chiggers on domestic rodents was 17.0%, and the chigger index was 5.38. The infestation rate of ticks on rodents was 3.1%. Natural infection of O. tsutsugamushi was found in Leptotrombidium taishanicum, L. linhuaikongense, L. intermedium, L. scutellare, L. palpale, and Ixodes spp., the minimum positive rates of which were 5.9%, 3.2%, 1.2%, 0.8%, 0.8%, and 2.2%, respectively. Kawasaki-like genotypes were predominant in chiggers and ticks on domestic rodents, which were detected from L. taishanicum, L. intermedium, L. scutellare, L. palpale, and Ixodes spp. Shimokoshi-like genotype was detected from L. palpale.ConclusionsIn the present study we investigated the infestation of chiggers and ticks on domestic rodents in Shandong Province, and identified the prevalence and genotypes of O. tsutsugamushi in the Acarina. Infestation of vector chiggers in domestic rodents, prevalence of O. tsutsugamushi in infested chiggers, and high nucleotide homologies among the O. tsutsugamushi sequences from the Acarina, their animal hosts and scrub typhus patients, implied that domestic rodents may play an important role in the transmission of scrub typhus in Shandong, China. Further studies are needed to verify the vector significance of chiggers and ticks that tested positive for O. tsutsugamushi, and to assess the risk of human exposure to chiggers and ticks on domestic rodents.
| S-EPMC3843596 | biostudies-literature
Project description:A survey of rodents and chiggers associated with Orientia tsutsugamushi was conducted in a rural region of the Republic of Korea (Korea) between 2014 and 2018. Overall Apodemus agrarius 15.2% had the highest seropisitive for O. tsutsugamushi, followed by Myodes regulus 11.4%. Monthly risk factors using logistic regression analysis were not associated with O. tsutsugamushi infections in rodents. The overall prevalence rate of O. tsutsugamushi among chiggers was 0.3%. The chigger (Leptotrombidium scutellare) and monthly (October) risk factors were associated with O. tsutsugamushi human infections (P<0.05). Orientia tsutsugamushi infections are endemic in rodents in Korea and people, for example, soldiers who are active outdoors, must employ preventive measures, especially during October (P<0.05). When there are many reports of O. tsutsugamushi infections in Korea. The Boryong strain 85.7% (2/14) was the most common strain detected in chiggers, followed by the Shimokoshi 7.1% (1/14) and Karp 7.1% strains.
| S-EPMC7672239 | biostudies-literature
Project description:During December 2012-July 2016, we tested small indoor and outdoor mammals in Qingdao, China, for Orientia tsutsugamushi infection. We found that outdoor Apodemus agrarius mice, Cricetulus barabensis hamsters, and Niviventer confucianus rats, as well as indoor Mus musculus mice, tested positive for O. tsutsugamushi by PCR.
| S-EPMC8462322 | biostudies-literature
Project description:Orientia tsutsugamushi Raw Sequencing Reads
| PRJNA316643 | ENA
Project description:Complete genomes of Orientia tsutsugamushi strains TW-1 and TW-22 in Taiwan
| PRJNA987430 | ENA
Project description:Scrub typhus has been documented since 1932 in Vietnam, however, the disease burden of scrub typhus remains poorly understood in the country. We conducted this study to describe the phylogenetic analysis of the 56-kDa type-specific antigen (TSA) gene of Orientia tsutsugamushi associated with PCR positive cases of scrub typhus. Of 116 positive samples, 65 type-specific antigen gene sequences were obtained and classified into 3 genogroups: Karp, Kato and Gilliam. The Karp genogroup was the most frequently detected phylogenetic cluster in the study with 30 samples (46%), followed by Kato and Gilliam with 20 (31%) and 15 (23%), respectively. All sequences showed 94-100% nucleotide similarity to reference sequences collected in the central part of Vietnam in 2017. Patients infected with Karp genogroup were more likely to have significant thrombocytopenia than the other genogroups. These results suggest that any scrub typhus vaccine considered for use in Vietnam should provide protection against each of these 3 genogroups.
| S-EPMC6716651 | biostudies-literature
Project description:Orientia tsutsugamushi is an obligate intracellular bacterium that causes scrub typhus, a potentially fatal rickettsiosis, and for which no genetic tools exist. Critical to addressing this technical gap is to identify promoters for driving expression of antibiotic resistance and fluorescence reporter genes in O. tsutsugamushi. Such promoters would need to be highly conserved among strains, expressed throughout infection, and exhibit strong activity. We examined the untranslated regions upstream of O. tsutsugamushi genes encoding outer membrane protein A (ompA), 22-kDa type-specific antigen (tsa22) and tsa56. The bacterium transcribed all three during infection of monocytic, endothelial and epithelial cells. Examination of the upstream noncoding regions revealed putative ribosome binding sites, one set of predicted -10 and -35 sequences for ompA and two sets of -10 and -35 sequences for tsa22 and tsa56. Comparison of these regions among geographically diverse O. tsutsugamushi patient isolates revealed nucleotide identities ranging from 84.8 to 100.0%. Upon examination of the candidates for the ability to drive green fluorescence protein expression in Escherichia coli, varying activities were observed with one of the tsa22 promoters being the strongest. Identification and validation of O. tsutsugamushi promoters is an initial key step toward genetically manipulating this important pathogen.
| S-EPMC8460164 | biostudies-literature
Project description:The relationship between land use structures and occurrence of scrub typhus agent, Orientia tsutsugamushi infection in small wild mammals was conducted in three provinces of Thailand: Buriram, Loei, and Nan. Orientia tsutsugamushi detection was performed using 16S ribosomal DNA (rDNA) amplicon sequencing approach using Miseq Illumina platform. In total, 387 animals (rodents and shrews) were examined for the bacterium infection. The 16S rDNA sequences of the bacterium were found in nine animals from Bandicota savilei, Berylmys bowersi, Leopoldamys edwardsi, Rattus exulans, R. tanezumi, and Rattus sp. phylogenetic clade 3, yielding 2.3% infection rate, with two new rodent species infected by the bacterium in Thailand: B. bowersi and L. edwardsi. Using a Generalized Linear Mixed Model (GLMM) and Random Forest analyses for investigating the association between human-land use and occurrence of the bacterium, forest habitat appeared as a strong explicative variable of rodent infection, meaning that O. tsutsugamushi-infected animals were more likely found in forest-covered habitats. In terms of public health implementation, our results suggest that heterogenous forested areas including forest-converted agricultural land, reforestation areas, or fallow are potential habitats for O. tsutsugamushi transmission. Further understanding of population dynamics of the vectors and their hosts in these habitats could be beneficial for the prevention of this neglected zoonotic disease.
| S-EPMC6082056 | biostudies-literature
Project description:Small mammals can transmit and serve as a reservoir for Orientia tsutsugamushi (Ot) in nature by carrying infected mites. In Yunnan, one of China's main foci of scrub typhus, etiological evidence and genetic diversity for Ot is limited. A total of 2538 small mammals were captured seasonally from 2015 to 2016 in the three counties of Yunnan, and the spleen or liver tissue was examined for Ot based on 56 kDa nPCR. The overall prevalence of Ot was 1.77%, ranging from 0.26 to 9.09% across different species. The Gilliam strain was found in 35.6% (16/45) of the wild small mammals, followed by the Karp 11.1% (5/45) and TA763 (1/45) strains, the last of which was discovered in western Yunnan for the first time. In Lianghe, Ot infection rates in wild small mammals were higher than in the other two counties. The infection rates of Eothenomys miletus with Ot were highest in the three dominant species. Ot infection rates in wild small mammals were higher in Lianghe (1200-1400 m) and Yulong (2800-3000 m). These findings could provide research clues for further confirmation of scrub typhus foci in western Yunnan or other similar natural environments.
| S-EPMC9862787 | biostudies-literature