Depends upon GM's description of the disease but usually contains several status effects. The typical disease will contain a mixture of effects such as poison, fatigue, and anxiety. Some diseases contain even more effects. The more powerful the disease, the harder it is to cure. One of the most dangerous diseases in Nor'Ova is the Bitterwood disease, which causes the inflicted to rot quickly while alive, like a dying tree. That would cause various status effects, such as dehydration, nausea, sickness, fatigue, depression, anxiety, confusion, and more, with more status effects coming and strengthening as the disease runs its course.
Some diseases can be cured by antibiotics, but only if the diseases are older or weaker in nature, or caught early enough to treat. The status effects causes by the disease may need treated as well.