Fig 1.
The geographic map of 3 study sites in Laos (Vientiane, Luang Namtha and Salavan).
Table 1.
List of 7 housekeeping gene and primer sequences used in this study.
Table 2.
In vitro isolations from patients recruited in Laos during August 2008 to December 2012.
Table 3.
Sequence type of 74 O. tsutsugamushi isolates from Laos.
The strain name prefix TM indicates samples from Vientiane, LNT those from Luang Namtha, and SV those from Salavan.
Fig 2.
Population genetic structure of O. tsutsugamushi in Laos and Thailand.
(A) O. tsutsugamushi population in Laos (n = 74). (B) The comparison of O. tsutsugamushi population in Laos and those in Thailand (n = 89) using comparative e-BURST in which blue dot were founders; pink letter were STs found in both sites; green letter were the STs found only in Laos and black demonstrated the ST found only in Thailand.
Fig 3.
Clonal complex of O. tsutsugamushi population from Laos and Thailand (163 isolates) using global optimal eBURST (goeBURST) with full minimum spanning tree (MST).
ST node colors are followed; green—group founder and light blue—common node.
Fig 4.
The phylogenetic tree of concatenated sequence of O. tsutsugamushi isolates from 74 Laos and 89 Thailand using neighbor-joining method with Bootstrap value of 3000.
The color triangle demonstrated isolates from different sites: black represented Vientiane; blue represented Luang Namtha; pink represented Salavan; grey were from Thailand and open triangle were reference isolates.
Fig 5.
Population differentiation (FST) based on concatenated sequences.
Populations were defined according to four strain sources; three from Laos (Vientiane, Luang Namtha and Salavan) characterised in the current study, and one population from Thailand (Udon Thani) characterised previously. The FST values are depicted as a dendrogram using the neighbour-joining algorithm.
Table 4.
The estimation selection in 7 housekeeping gene using the non-synonymous to synonymous amino acid substitution ratio (dN/dS) in this study.