[7] Found in Nepal, Thailand, Cambodia, Laos, Vietnam, northern West Malaysia and on the Indonesian island of Java.

In northern Malaysia it is responsible for some 700 incidents of snakebite annually with a mortality rate of about 2 percent.

[7] Its venom causes severe pain and local swelling and sometimes tissue necrosis, but deaths are not common.

Many victims are left with dysfunctional or amputated limbs due to the lack of antivenom and early treatment.

In a 2005 study of 225 Malayan pit viper (Calloselasma rhodostoma) bites in Thailand, most victims had mild to moderate symptoms, but 27 of 145 patients (18.6%) developed permanently swollen limbs.

The antivenin manufactured in Thailand seemed effective in reversing the blood clotting caused by the venom.

In a prospective phase of the study, bites occurred throughout the year but mostly early in the monsoon season (May and June).