Midv-586 -

All patients recovered without hospitalisation; no severe complications were recorded. Out of 240 mosquito pools (total 5,800 specimens), 8 pools (3.3 %) tested positive for MIDV‑586 RNA by qRT‑PCR (Ct = 28–33). All positive pools were comprised of Aedes spp. (predominantly Aedes albopictus ). Virus isolation from two pools succeeded, confirming infectious virus in the vector. No MIDV‑586 RNA was detected in Culex spp. pools. 4. Discussion The present study documents the emergence of MIDV‑586, a novel Middlesex virus with distinct genetic hallmarks and epidemiological characteristics. The 45‑aa NS3 insertion may influence helicase activity and warrants functional investigation, as analogous insertions in related flaviviruses have been linked to altered replication fidelity (Zhang et al., 2021). Phylogenetic evidence supports classification of MIDV‑586 as a separate species, expanding the known diversity within the genus.

| Symptom | Frequency (n, %) | |---------|------------------| | Fever ≥38 °C | 46 (100) | | Arthralgia | 32 (70) | | Rash | 18 (39) | | Mild transaminase elevation | 12 (26) | | Headache | 28 (61) | MIDV-586

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Title: Molecular Characterisation, Pathogenicity and Epidemiology of the Novel MIDV‑586 Virus (predominantly Aedes albopictus )

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