Rickettsia africae, Western Africa.
Ontology highlight
ABSTRACT:
SUBMITTER: Mediannikov O
PROVIDER: S-EPMC3322006 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:We detected Rickettsia africae, the agent of African tick-bite fever (ATBF), by amplification of fragments of gltA, ompA, and ompB genes from 3 specimens of Amblyomma loculosum ticks collected from humans and birds in New Caledonia. Clinicians who treat persons in this region should be on alert for ATBF.
| S-EPMC3204645 | biostudies-literature
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:The aim of the study was to reveal new aspects of the role of flea vector taken from migratory birds by screening of specimens with molecular biological methods. A field study was done in fishponds in Slovakia. Actually, 47 fleas were collected from reed warblers (Acrocephalus scirpaceus) and their nests. DNA was extracted and analyzed for representatives of the orders Rickettsiales. A rickettsia that shares 99.7% of identity by gltA gene with Rickettsia africae was identified in Ceratophyllus garei collected from A. scirpaceus. Moreover, two Wolbachia sp. were also detected in fleas. This is the first record of R. africae and Wolbachia sp. identified so far in Central Europe in fleas collected from migratory bird returning from Africa. This molecular study extends the geographic range and vector spectrum of arthropod-borne agents.
| S-EPMC3398393 | biostudies-literature
Project description: Not available
| S-EPMC2857237 | biostudies-literature
Project description: Not available
| S-EPMC3810746 | biostudies-literature
Project description:BackgroundRickettsia africae, the etiological agent of African tick bite fever, is widely distributed in sub-Saharan Africa. Contrary to reports of its homogeneity, a localized study in Asembo, Kenya recently reported high genetic diversity. The present study aims to elucidate the extent of this heterogeneity by examining archived Rickettsia africae DNA samples collected from different eco-regions of Kenya.MethodsTo evaluate their phylogenetic relationships, archived genomic DNA obtained from 57 ticks a priori identified to contain R. africae by comparison to ompA, ompB and gltA genes was used to amplify five rickettsial genes i.e. gltA, ompA, ompB, 17kDa and sca4. The resulting amplicons were sequenced. Translated amino acid alignments were used to guide the nucleotide alignments. Single gene and concatenated alignments were used to infer phylogenetic relationships.ResultsOut of the 57 DNA samples, three were determined to be R. aeschlimanii and not R. africae. One sample turned out to be a novel rickettsiae and an interim name of "Candidatus Rickettsia moyalensis" is proposed. The bonafide R. africae formed two distinct clades. Clade I contained 9% of the samples and branched with the validated R. africae str ESF-5, while clade II (two samples) formed a distinct sub-lineage.ConclusionsThis data supports the use of multiple genes for phylogenetic inferences. It is determined that, despite its recent emergence, the R. africae lineage is diverse. This data also provides evidence of a novel Rickettsia species, Candidatus Rickettsia moyalensis.
| S-EPMC4936727 | biostudies-literature
Project description:Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya. Of the 100 serum specimens tested from each species of domestic ruminant 43% of goats, 23% of sheep, and 1% of cattle had immunoglobulin G (IgG) antibodies to the SFG rickettsiae. None of these sera were positive for IgG against typhus group rickettsiae. We detected Rickettsia africae-genotype DNA in 92.6% of adult Amblyomma variegatum ticks collected from domestic ruminants, but found no evidence of the pathogen in blood specimens from cattle, goats, or sheep. Sequencing of a subset of 21 rickettsia-positive ticks revealed R. africae variants in 95.2% (20/21) of ticks tested. Our findings show a high prevalence of R. africae variants in A. variegatum ticks in western Kenya, which may represent a low disease risk for humans. This may provide a possible explanation for the lack of African tick-bite fever cases among febrile patients in Kenya.
| S-EPMC4208559 | biostudies-literature
Project description:Despite the increasing awareness of the importance of emerging vector-borne diseases, human tick-borne diseases, particularly rickettsial infections, are overlooked, especially in the countries such as Sudan with limited resources to perform molecular-based surveys. This study aimed at detection and genetic characterization of Rickettsia spp. in ticks collected from Sudan. The samples were first screened for the presence of rickettsial agents by gltA real-time PCR and subsequently characterized by gltA and ompA PCR and size-based multispacer typing. The results demonstrated the wide distribution of Rickettsia africae and/or closely related species across Sudan. The results of this report highlight the need for careful consideration of rickettsial infections in patients with nonmalarial febrile illness in this country. Nationwide surveillance on ticks associated with human rickettsial infections in Sudan is warranted.
| S-EPMC4449622 | biostudies-literature
Project description:Background: Ticks transmit a plethora of pathogens of zoonotic implications. Their distribution, diversity and the pathogens they transmit differ from one ecological location to another. Rickettsia africae is the agent of African tick bite fever found in South Africa, a zoonotic infection that is frequently reported among travelers who have visited many sub-Saharan African countries where the pathogen is prevalent. Methods: Ticks were collected from domestic animals in Raymond Nkandla Municipality, Eastern Cape, South Africa. The ticks were identified morphologically prior to DNA extraction followed by molecular identification of randomly selected ticks from the morphologically delineated groups. To assess for the presence of tick-borne pathogens belonging to Rickettsia spp. by PCR (polymerase chain reaction), we used specific primer pairs targeting the gltA, ompA and ompB genes. The selected amplified ticks, all positive ompB and forty three ompA amplicons were sequenced in a commercial sequencing facility. The obtained nucleotide sequences were edited and subjected to BLASTn for homology search and phylogenetic analyses were performed with MEGA 7 Version for genetic relationships with curated reference sequences in GenBank. Results: A total of 953 ticks collected in the study were delineated into three genera consisting of Amblyomma, Rhipicephalus and Hyalomma in decreasing order of abundance. The presence of rickettsial DNA was detected in 60/953 (6.3%) from the three genera of ticks screened. Genetic analyses of the DNA sequences obtained showed that they have phylogenetic relationship to members of the spotted fever group rickettsiae with R. africae, being the predominant SFGR (spotted fever group rickettsiae) detected in the screened ticks. Conclusion: This report shows that R. africae is the predominant spotted fever group rickettsiae in ticks collected from domestic animals in the study area and the human health impacts are not known.
| S-EPMC7459594 | biostudies-literature