# First laboratory-confirmed case of scrub typhus in Shijiazhuang City, Hebei Province

## TL;DR

This paper reports the first confirmed case of scrub typhus in Shijiazhuang City, identifying the causative strain as the Kawasaki genotype.

## Contribution

The study confirms the presence of scrub typhus in Shijiazhuang City and identifies the specific genotype for the first time in the region.

## Key findings

- The case was confirmed using Weil-Felix and IFA tests, showing increased antibody titers during recovery.
- PCR and phylogenetic analysis identified the strain as the Kawasaki genotype with high similarity.
- This is the first laboratory-confirmed case of scrub typhus in Shijiazhuang City.

## Abstract

Defining whether a suspected case was due to scrub typhus through laboratory testing, to understand the prevalence of scrub typhus in Shijiazhuang City, Hebei Province.

An epidemiological investigation was conducted on the suspected case, utilizing Weil-Felix test and indirect immunofluorescence assay (IFA) to detect specific antibodies against O. tsutsugamushi in serum specimens. Additionally, PCR amplification of the 56-kDa and groEL genes was performed, followed by constructing a phylogenetic tree to identify the genotype.

The acute phase titer of the Weil-Felix test for the case was 1:160, which increased to 1:320 in the recovery phase. IFA assay revealed IgG titers against O. tsutsugamushi of 1:64 in the acute phase and 1:256 in the recovery phase. Sequence alignment of the PCR amplified fragment showed the highest similarity with the O. tsutsugamushi genotype. Kawasaki sequence, ranging from 99.71 to 100.00%. The strain exhibited the closest genetic relationship with the known O. tsutsugamushi Kawasaki genotype.

This study confirms the presence of O. tsutsugamushi in Shijiazhuang City, Hebei Province, with the identified strain belonging to the Kawasaki genotype, marking the first diagnosis of this strain in the region.