Genomic characteristics of the first five monkeypox virus clade Ib cases in Thailand: August 2024–March 2025

@article{nitiyanontakij2026genomic,
  title = {{Genomic characteristics of the first five monkeypox virus clade Ib cases in Thailand: August 2024–March 2025}},
  author = {Ravee Nitiyanontakij and Sarinee Reawrang and Duangkamon Siludjai and Pornphimon Kaewsawang and Pimphorn Yooma and Ratchana Ponang and Pawita Suwanvattana and Peera Hemarajata and Wittawin Worakitchanon and Supaporn Wacharapluesadee and Tanawut Srisuk and Thidathip Wongsurawat and Piroon Jenjaroenpun and Worarat Kruasuwan and Pongpun Sawatwong and Woradee Lurchachaiwong and R. Suzanne Beard and Kitpong Sunchatawirul},
  journal = {Microbiology Spectrum},
  year = {2026},
  month = sep,
  doi = {10.1128/spectrum.00516-26},
  url = {https://doi.org/10.1128/spectrum.00516-26},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - Genomic characteristics of the first five monkeypox virus clade Ib cases in Thailand: August 2024–March 2025
AU  - Ravee Nitiyanontakij
AU  - Sarinee Reawrang
AU  - Duangkamon Siludjai
AU  - Pornphimon Kaewsawang
AU  - Pimphorn Yooma
AU  - Ratchana Ponang
AU  - Pawita Suwanvattana
AU  - Peera Hemarajata
AU  - Wittawin Worakitchanon
AU  - Supaporn Wacharapluesadee
AU  - Tanawut Srisuk
AU  - Thidathip Wongsurawat
AU  - Piroon Jenjaroenpun
AU  - Worarat Kruasuwan
AU  - Pongpun Sawatwong
AU  - Woradee Lurchachaiwong
AU  - R. Suzanne Beard
AU  - Kitpong Sunchatawirul
PY  - 2026
DA  - 2026/09/24
JO  - Microbiology Spectrum
DO  - 10.1128/spectrum.00516-26
UR  - https://doi.org/10.1128/spectrum.00516-26
AB  - Following the emergence of monkeypox virus clade Ib in the Democratic Republic of the Congo in August 2024, the World Health Organization declared a public health emergency of international concern because of sustained transmission and international spread. We characterized the first clade Ib cases detected in Thailand between August 2024 and March 2025 and assessed their phylogenetic relationships. Whole-genome sequencing was performed from lesion swabs of suspected cases. Phylogenetic analysis, incorporating clade Ia (DQ011155.1) and global clade Ib sequences from GISAID, confirmed all Thai isolates as clade Ib. The genomes showed close relatedness to clade Ib viruses reported internationally, consistent with patients’ travel histories. All isolates exhibited a 1,140-bp deletion in the C3L gene region and 52–61 amino acid substitutions compared with the clade Ia reference. Genome sequences were submitted to GISAID and NCBI to support outbreak response and improve understanding of epidemiologic patterns, enabling more effective public health interventions.  IMPORTANCE: On 14 August 2024, the World Health Organization declared the monkeypox virus outbreak in Africa a public health emergency of international concern following the emergence of clade Ib. One week later, Thailand confirmed the first monkeypox clade Ib case in Asia. Through whole-genome sequencing and phylogenomic analysis of five cases detected between August 2024 and March 2025, we identified a 1,140-bp deletion in the C3L gene region that distinguishes clade Ib from clade Ia. This deletion directly affects the performance of some commercial real-time PCR assays designed for clade Ia, which rely on amplification of the missing genomic region. Our findings highlight important diagnostic limitations that could lead to misinterpretation or reduced sensitivity in routine testing. Beyond confirming regional introduction linked to global spread, this study underscores the critical role of genomic surveillance in ensuring accurate diagnosis, monitoring viral evolution, and strengthening outbreak response as monkeypox continues to expand internationally.
SN  - 2165-0497
ER  -