Mumps Overview and Learning Objectives

Mumps Overview

• Mumps is an acute infectious disease caused by an RNA virus from the paramyxoviridae family
• The virus has a predilection for glandular and nervous tissue
• Clinically recognized by non-suppurative enlargement and tenderness of one or both parotid glands
• Other organs may be affected
• Symptoms vary, some cases may appear without noticeable symptoms
• Mortality rate is negligible, but morbidity rate is high
• Worldwide occurrence with peaks in epidemics every 2-5 years, typically during winter and spring
• Natural infection confers lifelong protection
• Incidence (without immunization) is 100-1000 cases per 100,000 population

Learning Objectives

• Identify the causative agent of mumps
• Understand the clinical presentation and complications of mumps
• Recognize available treatments and preventive measures for mumps

Agents Factor

• Agent: Myxovirus parotiditis — an RNA virus in the myxovirus family. Only one serotype exists.
• Source of Infection: Both clinical and subclinical cases contribute. Subclinical cases (accounting for 30-40% of all cases) are considered crucial for maintaining the infection cycle. The virus can be detected in saliva, surfaces of Stenson's duct, blood, urine, human milk, and occasionally cerebrospinal fluid (CSF).

Communicability Period

• Infectious period: 4-6 days before symptom onset and a week or more afterward
• Peak infectivity: Just before and at the onset of parotitis
• Non-infectious: Once swelling has subsided

Secondary Attack Rate

• Estimated at approximately 86%

Host Factors

• Age and Sex: Most common in children (5-9 years). Higher incidence than measles, chickenpox, or whooping cough. Adults experience a more severe disease than children if no prior immunity.
• Immunity: A single attack, either clinical or subclinical, typically induces lifelong immunity. There is only one antigenic type, and no significant antigenic variations. Infants under 6 months are usually immune due to maternal antibodies.

Mode of Transmission

• Primarily through droplet infection and direct contact with an infected person
• Often associated with overcrowding

Incubation Period

• Typically 14-18 days, varying from 2 to 4 weeks.

Clinical Features

• Generalized virus infection; 30-40% of cases are clinically non-apparent
• In apparent cases, characterized by pain and swelling in one or both parotid glands.
• May also involve sublingual and submandibular glands
• Often, initial complaint from child is "earache" on the affected side prior to swelling
• Pain and stiffness in the jaw may be experienced before swelling is noticeable
• Other symptoms may include fever, headache, muscle pain, pain when eating, loss of appetite

Complications

• Though frequent, complications are generally not serious
• Examples include orchitis, pancreatitis, meningoencephalitis, thyroiditis, neuritis, hepatitis, and myocarditis.
• Orchitis (most frequent in adults): Testicular swelling and tenderness, usually unilateral. High fever often accompanies this complication, appearing 7-10 days after parotitis in about 25-40% of post-pubertal males.
• Bilateral orchitis is rare; assumption that mumps orchitis causes sterility is unsubstantiated
• Pancreatitis: Upper abdominal pain, nausea, and vomiting suggest pancreatitis. Significantly impacted adults are likely post-pubertal
• Oophoritis: Lower abdominal pain and ovarian enlargement
• Rarer complications: nerve deafness, polyarthritis, hydrocephalus, encephalitis, cerebellar ataxia, facial palsy, and transverse myelitis
• Encephalitis leads to serious neurologic issues, cerebral edema, possible death
• Meningitis can develop as a complication in some cases.
• Infection in pregnancy's first trimester may increase the risk of spontaneous abortion, although congenital malformations are rarely linked.

Prevention

• Vaccination: MMR (Measles, Mumps, Rubella) vaccine is highly effective and is now widely available.
  • A single intramuscular dose (0.5 mL) leads to detectable antibodies in 95% of recipients.
  • Long-term immunity duration is yet unknown
  • Recommended for children over one year of age, either alone or with other virus vaccines.

Control

• Mumps control is challenging due to infectivity before diagnosis and a variable incubation period, along with subclinical cases.
• Isolated patients until symptoms subside, and disinfect used materials
• Monitoring of close contacts is important.
• Countries should set disease control targets and implement a strategic mumps immunization program accordingly

Mumps Surveillance

• WHO case definitions: Three categories to monitor: clinical mumps, laboratory-confirmed mumps, epidemiologically-confirmed mumps
• WHO defines appropriate methods for identifying and tracking mumps cases.

MMR Vaccine Contraindications

• Two or more doses of MMR after 12 months old
• Life-threatening allergic reactions to neomycin or other components
• Pregnant women or women planning pregnancy within 4 weeks
• Severely compromised immune systems

Vaccine Side Effects

• MMR vaccine is safe and effective
• Most people experience no side effects
• Some might experience mild fever, rash, or achy joints for a limited time
• Seizures caused by fever are possible but not associated with long-term issues.

Additional information

• Mumps is usually a self-limiting illness, resolving within a few weeks without specific treatment.

This quiz provides a comprehensive overview of mumps, including its causative agent, clinical presentation, and complications. Participants will learn about the treatment options and preventive measures available for this infectious disease. Test your knowledge on the epidemiology and characteristics of mumps.