Emerging infectious diseases
September 1, 2026 · via Europe PMC
Reemergence of Scrub Typhus Associated with Leptotrombidium akamushi Mites and Karp-Like Orientia tsutsugamushi Genotype Bacteria, Japan, 2024-2025.
Ogawa M, Takada N, Katayama T, Hashimoto Y, Nagano K, Komine H, Akeda Y.
AI summary — for doctors, generated from the abstract only
A fatal-to-the-fetus summer scrub typhus case in Japan was traced to Leptotrombidium akamushi mites carrying an unusual Karp-like Orientia tsutsugamushi genotype.
What was studied
Investigation of a scrub typhus case in a pregnant woman who attended a fireworks event in Niigata Prefecture in August 2024, including genotyping of patient samples and field collection of mites and rodents at the site.
Key findings
- The patient developed scrub typhus after the event, resulting in fetal death
- A Vietnam-related Karp-like O. tsutsugamushi genotype was detected, distinct from the Kato type usually linked with L. akamushi
- Field investigation showed seasonal predominance of L. akamushi mites in summer
- Sequences identical to the patient's strain were found in three L. akamushi larvae and one field mouse
Clinical relevance
Clinicians in Japan may need to consider scrub typhus outside the usual spring and autumn seasons, especially after outdoor exposure in summer; this is a single case with supporting field data.
Who should care
Limitations
One human case with ecological investigation at one site, so broader reemergence cannot be quantified.
Summer scrub typhus appears to be resurfacing in Japan, carried by a mite species and genotype not usually paired.
This is an AI-generated summary of the published abstract, not a clinical recommendation. It may not reflect the full text or subsequent updates — verify against the original source before acting on it.
Abstract
Scrub typhus is a miteborne infectious disease caused by Orientia tsutsugamushi bacteria. In Japan, most cases occur in spring and autumn and are transmitted by Leptotrombidium pallidum and L. scutellare mites; summer scrub typhus, transmitted by L. akamushi mites, is rarely reported. In August 2024, a pregnant woman had scrub typhus develop after attending a fireworks event in Niigata Prefecture, Japan, resulting in fetal death. A Vietnam-related Karp-like O. tsutsugamushi genotype, distinct from the Kato type usually associated with L. akamushi mites, was detected from patient samples. Field investigations at the site of the fireworks event revealed seasonal predominance of L. akamushi mites in summer. We detected O. tsutsugamushi sequences identical to the patient's strain in 3 L. akamushi mite larvae and 1 field mouse, suggesting that L. akamushi mites were the source of human infection. Our findings suggest reemergence of summer scrub typhus associated with infected L. akamushi mites carrying a locally novel genotype.
DOI
10.3201/eid3209.260646
PMID
42661144
PMCID
PMC13555703
Research metadata (titles, abstracts, authors, publication dates) is sourced from Europe PMC, which aggregates content from PubMed/MEDLINE, PubMed Central, and other providers under the U.S. National Library of Medicine (NLM/NCBI). NLM does not claim copyright on abstracts; the original journal publishers or authors may hold rights to the full articles. AI-generated summaries are derived only from the abstract, never the full text, and are always labeled as AI-generated.
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