Mumps
Mumps is spread from person to person through contact with respiratory secretions, such as saliva from an infected person. When an infected person coughs or sneezes, the droplets aerosolize and can enter the eyes, nose, or mouth of another person. Mumps can also be spread by sharing eating utensils or cups. The virus can also survive on surfaces and then be spread after contact in a similar manner. A person infected with mumps is contagious from approximately seven days before the onset of symptoms until about eight days after symptoms start. The incubation period (time until symptoms begin) can be from 12–25 days, but is typically 16–18 days. 20-40 percent of persons infected with the mumps virus do not show symptoms, so it is possible to be infected and spread the virus without knowing it.
Sialadenitis
Viral pathogens more commonly cause sialadenitis in comparison to bacterial pathogens. Mumps is the most common virus that affects the parotid and submandibular glands, with the parotid gland affected most often out of these two. Other viruses that have been shown to cause sialadenitis in both these glands include HIV, coxsackie and parainfluenza. Classically, HIV parotitis is either asymptomatic or a non-painful swelling, which is not characteristic of sialadenitis. Some common bacterial causes are S. Aureus, S. Pyogenus, S. Viridans and H. Influenzae.