Laryngitis is an inflammation of the mucous membranes of the larynx. Signs of laryngitis include hoarseness and loss of voice. The most common causes are excessive meowing and a chronic cough. Both cause vocal cord strain.
Laryngitis can be associated with tonsillitis, throat infections, tracheobronchitis, pneumonia, inhalant allergies, and (rarely) tumors in the throat. The lining of the larynx is not coated with cilia. Therefore, mucus frequently accumulates in the larynx. Exaggerated throat clearing is needed to dislodge it. This further irritates the larynx and lowers resistance to infection.
Toxoplasmosis is a disease caused by the parasite Toxoplasma gondii, which can be found in garden soil and raw meat. Cats can get toxoplasma infection by killing and eating infected prey. The disease can also be passed on from cats to humans.
Treatment: Laryngitis due to excessive meowing usually responds to removing the cause of the cat’s anxiety or distress. If the problem is due to prolonged coughing, seek veterinary attention to investigate and eliminate the cause of the chronic cough.
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"