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
Tay–Sachs disease Researchers are looking at gene therapy or enzyme replacement therapy as possible treatments. Tay–Sachs disease is typically first noticed in infants around 6 months old displaying an abnormally strong response to sudden noises or other stimuli, known as the "startle response". There may also be listlessness or muscle stiffness (hypertonia). The disease is classified into several forms, which are differentiated based on the onset age of neurological symptoms. Until the 1970s and 1980s, when the disease's molecular genetics became known, the juvenile and adult forms of the disease were not always recognized as variants of Tay–Sachs disease. Post-infantile Tay–Sachs was