Bordetella parapertussis evolved in a host population that had already developed immunity to "B. pertussis", where being able to evade "B. pertussis" immunity was an advantage. Two lineages of "B. parapertussis" have been described. The first infects humans and is responsible for a minority of cases of the disease pertussis (also known as whooping cough). The second, ovine, lineage causes chronic nonprogressive pneumonia in sheep. Both lineages are thought to have evolved from a "B. bronchiseptica"-like ancestor. This disease can be symptomatic or asymptomatic and may predispose hosts to secondary infection. Bordetella parapertussis Bordetella parapertussis is a small Gram-negative bacterium of the
Heavy chain disease cell receptor, presumably due to the loss of the anti-aggregating properties of the light chain. There are four forms: The most common type of heavy chain disease is the IgA type, known as αHCD. The most common type of αHCD is the gastrointestinal form (known as immunoproliferative small intestine disease or IPSID), but it has also been reported in the respiratory tract, and other areas of the body. Franklin's disease (gamma heavy chain disease) It is a very rare B-cell lymphoplasma cell proliferative disorder which may be associated with autoimmune diseases and infection is a common characteristic of the disease.