Whooping cough eight weeks, or sometimes longer. A gradual transition then occurs to the convalescent stage, which usually lasts one to four weeks. This stage is marked by a decrease in paroxysms of coughing, although paroxysms may occur with subsequent respiratory infection for many months after the onset of pertussis. The time between exposure and the development of symptoms is on average 7–14 days (range 6–20 days), rarely as long as 42 days. Pertussis is caused by the bacterium "Bordetella pertussis". It is an airborne disease (through droplets) that spreads easily through the coughs and sneezes of an infected person. Uncertainties have
Byne's disease high humidity can also affect pyrite (or its more reactive polymorph marcasite) (iron sulphide) fossils in a somewhat similar condition, which is known as pyrite disease. The iron sulfide can react with water and oxygen to form iron sulfates and sulfuric acid, which then can produce Bynesian decay. Byne's disease Byne's disease, more accurately known as Bynesian decay, is a peculiar and permanently damaging condition (resulting from an ongoing chemical reaction) which often attacks mollusk shells that are in storage or on display for long periods of time. Bynesian decay is a form of efflorescence of salts formed by the