Genotypic Heterogeneity of Orientia tsutsugamushi in Scrub Typhus Patients and Thrombocytopenia Syndrome Co-infection, Myanmar

Abstract

Serologic and molecular surveillance of serum collected from 152 suspected scrub typhus patients in Myanmar revealed Orientia tsutsugamushi of genotypic heterogeneity. In addition, potential co-infection with severe fever with thrombocytopenia syndrome virus was observed in 5 (3.3%) patients. Both scrub typhus and severe fever with thrombocytopenia syndrome are endemic in Myanmar.

Keywords: Bacteria; Myanmar; Orientia tsutsugamushi; co-infection; differential diagnosis genotypes; mite-borne infections; phylogenic analysis; scrub typhus; thrombocytopenia syndrome virus; tsutsugamushi; vector-borne infections; viruses.

Figure 1

Locations in Sagaing and Magway Provinces in Myanmar, where suspected scrub typhus patients’ serum samples were collected for study of genotypic heterogeneity of Orientia tsutsugamushi.

Figure 2

Phylogenetic tree constructed on the basis of Orientia tsutsugamushi tsa56 gene sequences for scrub typhus patients in Myanmar (black dots) and reference sequences. The tree was constructed using the maximum likelihood method with MEGA7 (http://www.megasoftware.net). The tsa56 gene sequences identified in this study are indicated by black circles and compared with 17 representative genotype sequences reported by a previous study (1). The percentage of replicate trees in which the associated genotypes clustered together in the bootstrap test (1,000 replicates) is shown next to the branches.