Case report of juvenile Ovophis makazayazaya (Taiwan mountain pit viper) envenoming from Taiwan.

Ovophis makazayazaya is a medically important pit viper with a wide geographic distribution in Asia. The documented cases of human envenoming are rare in the literature. There has been no published report of juvenile O. makazayazaya envenoming. This report represents the initial documentation of such a case, underscoring a rare clinical event and the possibility of ontogenetic venom variation. The incident involved a 21-year-old male who suffered envenoming from juvenile O. makazayazaya bite to the right foot, exhibiting local toxicities characterized by pain, progressive swelling, and minor bruising. There was no systemic coagulopathy, thrombocytopenia, muscle damage, kidney injury, or neurological deficit detected during the hospital course. The patient received paraspecific antivenom therapy and was stable for discharge after three days, with no adverse reactions from the antivenom during the hospital stay. Knowledge of the clinical features and management strategies of juvenile O. makazayazaya envenoming is vital to facilitate optimal medical care in these patients.