"It's just better to be dead, trust me."
Hollowcurse is a very rare illness that occurs after someone has been attacked by giant moths and manages to survive by some miracle. It has many stages of development that are sadly poorly documented as it is highly unlikely that someone manages to get away from those deadly creatures and
manages to get to safety before they bleed out and
manages to get the expert medical care that is required to get a correct diagnosis and treatement. Because of its volatile and changing nature, many fairy tales and other legends featuring people acting possessed or unpredictable or with violent outburst are sometimes thought of as a hollowcure is later stage of their sickness. If you follow the folk legends deeper into the conspiracy territory, some people also think that this sickness is the way how the moths prepare the living bodies for larvae development to make more giant moths. No one has been brave and stupid enough to try to research all this. Officially.
It's hard to tell if someone is hollowcurse or not. Among the very common symptoms belong fatigue, lethargy, depression, memory loss and weight gain. After that some physical changes might happen like decreased heartbeat and blood pressure, decreased body tempterature and pasty white skin. Further along, movement becomes more difficult, there is possibly some irreversible nerve damage going on and the bones are starting to get brittle. Accompanying that are the weird psychological senses. Speaking in tongues. Lashing out with sudden increases of energy and strength. As time progresses, so do the self-destructive behaviours. Some people can have only one of these symptoms accompanied with other ones like weird rashes for example. The only true common denominator for all the sick cases has been death and violent attacks against other people and animals. Essentially anything living within their reach.
The fear of this sickness is one of the primary reasons why so many people do not dare to leave their islands and travel through the mist even with experienced guides.