Two lineages of B. parapertussis which is a small Gram-negative bacterium have been described, the first infects humans and the second causes chronic nonprogressive pneumonia in sheep.
Bordetella parapertussis is a small Gram-negative bacterium of the genus Bordetella that is adapted to colonise the mammalian respiratory tract. 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. 
