Genetic diversity of Rickettsia africae isolates from Amblyomma hebraeum and blood from cattle in the Eastern Cape provi
- PDF / 992,341 Bytes
- 13 Pages / 439.37 x 666.142 pts Page_size
- 65 Downloads / 188 Views
Genetic diversity of Rickettsia africae isolates from Amblyomma hebraeum and blood from cattle in the Eastern Cape province of South Africa Alicia D. Pillay1 · S. Mukaratirwa1,2 Received: 7 July 2020 / Accepted: 29 September 2020 © Springer Nature Switzerland AG 2020
Abstract Rickettsia africae is a re-emerging tick-borne pathogen causing African tick bite fever (ATBF) in humans. Amblyomma variegatum is the principal vector in most sub-Sahara African countries, whereas in South Africa it is A. hebraeum. Reports of high genetic heterogeneity among R. africae isolates in southern Africa have prompted the need for molecular investigations of isolates form South Africa. Therefore, this study aimed to determine the prevalence and genetic diversity of R. africae in A. hebraeum collected from cattle, grazing pasture, as well as from blood of cattle in the Eastern Cape Province of South Africa. Amblyomma hebraeum and blood from cattle were screened by PCR and the gltA, ompA, ompB, sca4, and 17kDa genes were sequenced for R. africae from samples collected from Caquba in Port St. Johns along the coastal region in the Eastern Cape province of South Africa. The overall proportion of adult A. hebraeum that were positive for the gltA and ompA genes was 0.63 (108/180). The overall proportion of nymphs positive for the gltA and ompA genes was 0.62 (23/37) and 0.22 (20/90) from cattle blood. A positive R. africae infection was inferred by analysis of 26 sequences of the ompA, gltA, ompB, 17kDa and sca4 genes. Neighbour-joining and Maximum Likelihood analysis revealed that the study isolates were closely related to R. africae isolates from South Africa deposited in GenBank, forming a clade that was separate from north, east and west African strains. This study provides new information on the epidemiology and phylogeny of R. africae isolated from A. hebraeum ticks in the Eastern Cape province of South Africa. The heterogeneity observed between R. africae isolates from South Africa deposited in GenBank and R. africae isolates from Africa retrieved from Genbank highlight the importance of differentiation and tracking of the genetic movement among R. africae isolates in southern Africa for the better characterisation of ATBF cases, especially in rural communities and travellers visiting the region. Keywords African tick-bite fever · Amblyomma hebraeum · Rickettsia africae · Spotted fever · Travel medicine Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1049 3-020-00555-6) contains supplementary material, which is available to authorized users. * S. Mukaratirwa [email protected] Extended author information available on the last page of the article
13
Vol.:(0123456789)
Experimental and Applied Acarology
Introduction Rickettsia africae is an obligate, intracellular bacterium belonging to the spotted fever group Rickettsiae (Raoult 1997). It is the etiological agent of African tick bite fever (ATBF), an emerging infectious disease endemic to sub-Saharan Africa (Freedman et al
Data Loading...
