Relapsing fever causative agent in Southern Iran is a closely related species to East African borreliae

Abstract

We obtained two blood samples from relapsing fever patients residing in Jask County, Hormozgan Province, southern Iran in 2013. Sequencing of a partial fragment of glpQ from two samples, and further characterization of one of them by analyzing flaB gene, and 16S-23S spacer (IGS) revealed the greatest sequence identity with East African borreliae, Borrelia recurrentis, and Borrelia duttonii, and Borrelia microti from Iran. Phylogenetic analyses of glpQ, flaB, and concatenated sequences (glpQ, flab, and IGS) clustered these sequences amongst East African Relapsing fever borreliae and B. microti from Iran. However, the more discriminatory IGS disclosed a unique 8-bp signature (CAGCCTAA) separating these from B. microti and indeed other relapsing fever borreliae. In southern Iran, relapsing fever cases are mostly from localities in which O. erraticus ticks, the notorious vector of B. microti, prevail. There are chances that this argasid tick serves as a host and vector of several closely related species or ecotypes including the one we identified in the present study. The distribution of this Borrelia species remains to be elucidated, but it is assumed to be endemic to lowland areas of the Hormozgan Province, as well as Sistan va Baluchistan in the southeast and South Khorasan (in Persian: Khorasan-e Jonobi) in the east of Iran.

Relapsing Fevers: Neglected Tick-Borne Diseases

“…Although they harbor differences in their rates of evolution and robustness, several molecular chronometers of RF borreliae housekeeping genes (e.g., 16S rRNA, flagellin, glycerophosphodiester phosphodiesterase GlpQ) and non-coding sequences from the linear chromosome are quite congruent to delineate TBRF phylogenesis (Fukunaga et al, 1996 ; Ras et al, 1996 ; Scott et al, 2005 ; Oshaghi et al, 2011 ). Single gene phylogenetic analyses are supported by studies of multiple loci (2 to 7 among rrs, flaB, glpQ, groEL, p66, recG , and 16S−23S rRNA intergenic spacer IGS) (Toledo et al, 2010 ; Trape et al, 2013 ; Naddaf et al, 2017 ), extended multilocus phylogenetic analysis (MLPA) panel of 25 conserved coding DNA sequences (Adeolu and Gupta, 2014 ) and phylogenetic analysis based on 266 sets of single-copy orthologues present in all genomes (Di et al, 2014 ). According to the highest resolutive methods, TBRF borreliae embrace four lineages also harboring common ecological features, including a vector of Ixodidae (“Hard-ticks”) or Argasidae (“Soft-ticks”) family and/or geographic distribution: (1) Old-World TBRF borreliae, (2) New-World TBRF borreliae, (3) the worldwide avian TBRF borreliae (i.e., B. anserina ) and (4) the HTBRF group (Table 1 ; Adeolu and Gupta, 2014 ; Di et al, 2014 ).…”

“…B. kalaharica” and a new clinical Borrelia sp. in Iran) (Fingerle et al, 2016 ; Naddaf et al, 2017 ) and would require additional phylogenetic analysis to clarify relationships between lineages. In addition, several TBRF borreliae species could not be included in any phylogeny comparison because no DNA sequences have been available so far ( B. venezuelensis, B. caucasica, B. harveyi, B. dugesii, B. braziliensis, B. graingeri, B. mazzottii, B. tillae , and B. baltazardii ).…”

Development of A Loop-Mediated Isothermal Amplification (LAMP) Assay for Detection of Relapsing Fever Borreliae

“…The DNA samples were examined by the LAMP, and a Borrelia -specific nested PCR that amplifies the rrs-rrl -IGS region using the outer primers F, 5′-GTATG TTTAGTGAGGGGGGTG-3′ and R, 5′-GG ATCATAGCTCAGGTGGTTAG-3′ and inner nested primers F, 5′-AGGGGGGTGAAGTC GTAACAAG-3′ and R, 5′-GTCTGATAAACC TGAGGTCGGA-3′ ( 18 ). This PCR has exhibited high sensitivity in detecting relapsing fever borreliae ( 3 , 8 , 19 , 20 ). In all assays, for specificity test, DNAs from other bacteria species were included and DDW was used as a negative control.…”

“…In Iran, four RFB, including Borrelia persica , Borrelia microti , Borrelia latyschewii and Borrelia baltazardi have been described ( 5 ). Borrelia persica is the primary cause of the disease especially in the west and northwest of the country ( 5 – 7 ), while in the south, epidemiological data and molecular approved human infections indicated B. microti and other B. microti -like borreliae as the other cause of relapsing fever ( 3 , 8 , 9 ).…”

“…However, between the peaks and in milder diseases, the bacteria are scanty and are hard to identify in blood smears. In Iran, PCR assays using various molecular markers like flaB , glpQ and rrs have successfully detected the Borrelia spp in relapsing fever patients ( 3 , 8 ) and animals ( 10 ). The PCR assays exhibit high sensitivities but are not commonly affordable in resource-limited laboratories of rural areas, where most of the relapsing fever infections occur.…”