Choriocytosis
Choriocytosis was a virus affecting the ability of blood s to carry oxygen to the body's organs. It was known to affect Humans and Vulcans. 

While Humans were minimally affected, the virus was extremely deadly to Vulcans with their copper-based blood system; death could occur within a week as the victim essentially suffocated internally. Initial symptoms included increasing lethargy as the body lost access to oxygen.

The only known treatment was strobolin, a rare, naturally-occurring substance that was only found on a few planets. A synthesized version could be administered to slow the progression of the disease, but the recipient became immune within days. Obviously, this kind of infection was considered a medical emergency, prompting coordinated delivery with multiple ships when necessary.

In 2270 the  was affected by an outbreak of choriocytosis that was eventually brought under control by the administration of strobolin. ()

de:Choriozythose
it:Coriocitosi
Medical conditions