Info that may help....
Phil25 wrote a 'Roll the Dice' plugin with a Toxic effect. It shows a cloud around the player and damages enemies in range. Unfortunately it doesn't damage friendlies. Link:
https://forums.alliedmods.net/showthread.php?t=278579
Settings:
"radius" "128.0" — Toxic cloud radius.
"interval" "0.2" — Interval in seconds damaging occurs.
"damage" "20.0" — Amount of damage dealt.
Here's a short video I made on what the Toxic perk from Roll the Dice looks like in game:
https://youtu.be/9rwhlb0NY88
And since we're on the topic of the virus... bookmark this link from John Hopkins University showing global cases to stay informed:
https://www.arcgis.com/apps/opsdashb...23467b48e9ecf6