"One long, poisonous fang was sinking deeper and deeper into his arm"
Cobra
Creative Commons AttributionCobra - Credit: Saleem Hameed

Venomous snakes can be found everywhere in the world except Antarctica and certain islands. Poisonous snakebites are not necessary fatal, depending on how quickly medical care is provided, the health of the person and the amount of venom injected. 

The most common symptoms of snakebites are panic, nausea, fainting, vomiting, diarrhea, sweating and cold skin.

Aside from basilisks, almost all of the world's most deadly serpents are to be found in Australia.  These include the taipan, the Australian brown snake and the death adder.  Elsewhere, particularly dangerous snakes include Africa's puff adder and black mamba, and India's common krait and saw scaled viper.