Etiology and historical background
The pathogen belongs to the family Paramyxoviridae, genus Rubulavirus. It is an enveloped virus measuring 80–350 nm, exhibiting pronounced pleomorphism. Its genome is represented by an unsegmented single-stranded RNA molecule, the replication of which occurs in the cytoplasm of the infected cell. The genetic apparatus includes 7 genes encoding 8 proteins, among which are the nucleocapsid (NP), matrix (M), fusion (F), and hemagglutinin-neuraminidase (HN) proteins.
The virus is characterized by high antigenic stability: genetic recombination is not typical for it, therefore only a single serotype of the pathogen is known. The external environment rapidly inactivates the virus.
Historically, the disease and one of its formidable complications (orchitis) were described by Hippocrates as early as the 5th century BC. The viral nature of the infection was proven in 1934 by researchers Johnson and Goodpasture, who infected macaques with the saliva of an ill person. In 1949, domestic scientists A.K. Shubladze and M.A. Selimov first isolated this agent in chicken embryos.
Epidemiological features
The infection is transmitted from person to person. Susceptibility of the non-immune population to the mumps virus is universal, regardless of age. The contagiousness index is very high (comparable to influenza and rubella), although somewhat inferior to measles and chickenpox.
Mass immunization has radically changed the epidemiological landscape. In the Russian Federation, the incidence rate decreased from 98.9 to 1.64 per 100,000 population. However, a new trend has emerged — the "aging" of the infection. In countries with developed vaccine prophylaxis, outbreaks are increasingly recorded among older adolescents and young adults (17–25 years old). This is due to the gradual waning of post-vaccination immunity and a decrease in protective antibody titers.
Pathogenesis
The entry portal of the infection is the mucous membrane of the respiratory tract. Primary replication of the virus occurs in the epithelial cells of the mucosa and regional lymph nodes.
Following accumulation, the pathogen breaks into the systemic bloodstream, causing viremia. The blood carries the virus throughout the body, ensuring the generalization of the process. The pathogen settles and actively replicates in target tissues: the salivary glands, pancreas, testicles, and structures of the central nervous system. The disease concludes with the development of an immune response and the elimination of the pathogen from the body.
Clinical presentation
The disease begins acutely with intoxication syndrome: febrile fever, pronounced weakness, and headache. Catarrhal symptoms are absent.
A specific manifestation is involvement of the salivary glands. The patient reports pain on chewing and difficulty opening the mouth (trismus). Facial asymmetry develops due to bulging of the parotid region. Palpation reveals a tender mass of doughy consistency, not fixed to the underlying tissues. An important differential sign: the skin over the swelling retains normal color, with no hyperemia or fluctuation. In the oropharynx, Mursu's sign is detected — swelling and redness of the papilla of the parotid duct orifice.
On days 5–6, against the background of intense viremia, complications may manifest:
- Pancreatitis: pain in the epigastric and mesogastric regions.
- Serous meningitis: a sharp spike in temperature (up to 39.4°C), photophobia, hyperesthesia, orthostatic dizziness, repeated vomiting, and the appearance of meningeal signs.
Diagnosis and management tactics
Mumps infection must be distinguished from bacterial sialadenitis, infectious mononucleosis, and adenovirus infection. A frequent diagnostic error at an early stage is diagnosing "lymphadenitis" and mistakenly prescribing antibiotics.
The examination algorithm includes:
- Assessment of the epidemiological history (lack of vaccinations, group morbidity).
- Biochemical blood test for amylase and urine test for diastase.
- Serological tests: CF fixation and ELISA to detect antibodies to the virus.
- Instrumental: ultrasound of the salivary glands and abdominal organs.
- In the presence of meningeal symptoms — consultation with a neurologist to decide on a lumbar puncture.
Patients are subject to hospitalization in an infectious diseases hospital for isolation from non-immune individuals and implementation of symptomatic therapy.
Briefly: answers to topical questions
What is the mechanism and transmission routes of mumps?
The main transmission mechanism of mumps is airborne. Infection routes:
- Airborne droplet — the main route; the aerosol has low dispersion, so the virus settles quickly and does not spread over large distances from the source.
- Contact — via items contaminated with the patient's saliva (dishes, toys, keyboard); this route is of limited importance due to the instability of the virus in the external environment. Additional environmental contamination can occur via urine.
- Transplacental — infection of the fetus.
- Lactogenic — infection of infants via breast milk.
The presence of concurrent acute respiratory infections in the source of infection accelerates spread, as it enhances the release of the virus into the external environment during coughing and sneezing.
What complications can occur in mumps on days 5–6 of the disease?
On the 5th day of the disease, the development of central nervous system involvement in mumps infection — serous meningitis — is possible.
This may be indicated by:
- sudden temperature spike up to 39.4°C;
- increased headache;
- dizziness, especially when standing (orthostatic);
- photophobia;
- recurrent vomiting;
- hyperesthesia — increased sensitivity to bright light and noise.
In the presence of meningeal symptoms, consultation with a neurologist is mandatory to determine indications for lumbar puncture.
What does specific prophylaxis of mumps consist of, and what are the vaccination schedules?
Specific prophylaxis of mumps consists of active immunization with a live attenuated mumps vaccine (as a monovaccine or combination preparations). Vaccination schedules:
- Scheduled vaccination — administered to children at 12 months of age (subcutaneously under the shoulder blade or into the outer surface of the shoulder).
- Revaccination — carried out at 6 years of age.
- Emergency prophylaxis — indicated for unvaccinated and previously uninfected individuals; the preparation must be administered no later than 72 hours after contact with an infected person.
Class and exam questions
Why is epidemic parotitis often mistakenly diagnosed as lymphadenitis?
Due to the similar localization of swelling in the angle of the lower jaw. The main differences of mumps: doughy consistency of the formation, absence of skin hyperemia over it, and absence of purulent melting (fluctuation).
What is Mouradian's sign?
This is local hyperemia and edema of the papilla of the parotid salivary gland excretory duct, detected upon examination of the oral mucosa.
Why does the virus affect not only the salivary glands, but also the central nervous system and the pancreas?
The mumps virus possesses a pronounced tropism for glandular epithelium and nervous tissue due to the presence of specific cellular receptors containing sialic acid in them.
What is the reason for the «aging» of the infection in recent decades?
The shift in morbidity toward older schoolchildren and young adults is associated with the gradual waning of post-vaccination immunity (decrease in protective antibody titers) in these age groups.
What else to study on this topic
- Criteria for assessing the severity of the course of mumps infection.
- Features of the clinical presentation and diagnosis of mumps orchitis.
- CSF analysis in the development of mumps meningoencephalitis.
- Features of the formation of post-infection immunity.
- Modern regimens of active specific immunization and isolation periods for contacts.
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