Featherlung

Featherlung was a respiratory disease. It was one of The Three Plagues of the more well-known contagious diseases of Faerûn.

Effects
Featherlung was spread by inhalation, and took one to three days to take effect.

One version of featherlung filled the lungs with dying flesh, which asphyxiated the victim. Another dried up the lungs and reduced their capacity, eventually suffocating the sufferer.

Assisted manual ventilation (repeated lifting of the body and depressing the chest) was of no help since it was oxygen already in the lungs that wasn't being processed properly. This left sufferers weak and almost helpless, drifting in and out of consciousness and making them easy targets for opportunists. Even if properly treated, someone with featherlung could take a tenday or more to die, though if left without access to water, thirst frequently killed them before the disease could.

Once someone was infected with featherlung, they became immune to the disease. However, even those that survived the illness sometimes had difficulty breathing in dry weather.

History
In Marpenoth of the Year of the Shield, 1367 DR, the city of Procampur in the Vast was struck by a featherlung plague (of the first kind). It killed hundreds of people, particularly in the District of the Poor. Procampur's wards were slow to react, and to be treated by clerics of Helm and Torm, the sick had to cross the city to reach the Temple District, thus spreading the plague further. High priests Orn Thavil of Tymora and Baniya Dolester of Lliira went to the poor district to set up an auxiliary shrine and treated the sick directly, and other priests soon joined then. Though their actions halted the spread of the disease, the Thultyrl reprimanded both high priests for breaking Procampur's district rules, and were reminded that the city and its laws were older than a number of deities.

In approximately 1475 DR, a featherlung epidemic (of the second kind) swept through Waterdeep killing several hundred people.