Properdin employs the alternative pathway of the complement system. The central c3 protein is cleaved by the generation of c3 convertase. Numerous interaction between the ligands and the subunits of Properdin are involved in activating the pathway.
Answer: The etiology of the symptoms is the bacterium Bordetella pertussis.
Explanation: Etiology implies the "cause of" or "origin of" a disease. Paroxysmal cough is most commonly caused by the bacterium Bordetella pertussis. The cough is also accompanied by mucus accumulation in the airways. The bacterium infects the respiratory tract of an individual causing consistent coughing and excessive mucus production.
