Mumps Virus – Morphology, Resistance, Pathogenesis, Clinical features, Laboratory Diagnosis & Prophylaxis

INTRODUCTION TO MUMPS VIRUS

⇒ MUMPS VIRUS  is the causative agent of disease MUMPS, an acute infectious disease commonly affecting children and characterized by Parotitis (inflammation of parotid glands).

⇒ It had been described by Hippocrates in the fifth century BC as ‘Epidemic Parotitis’.

⇒ This virus belongs to the Rubulavirus genus of Paramyxoviridae

MORPHOLOGY OF MUMPS VIRUS

⇒ It Resembles orthomyxovirus in morphology – Spherical, Enveloped virus with helical Nucleocapsid (13-18 nm).

⇒ Size: 100-250 nm in diameter.

⇒ The envelope is covered by projections of HN (Hemagglutinin, Neuraminidase) and F (Fusion protein) peplomers.

⇒ Genetic Material:- Linear ssRNA

⇒ There is only one serotype of Mumps virus.

RESISTANCE SHOWN BY MUMPS VIRUS

⇒ The mumps virus is labile, rapidly inactivates at room temperature.

⇒ Exposure to formaldehyde, ether or ultraviolet light inactivates the virus particle.

⇒ It can be preserved at –70^oC or by lyophilization.

PATHOGENESIS OF MUMPS VIRUS

⇒ This virus causes the disease mumps, an acute infectious disease characterized by non-suppurative enlargement of the parotid gland and Parotitis.

The virus is Acquired by Inhalation and

through the conjunctiva.

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The virus replicates in upper respiratory tract &

Cervical lymph nodes.

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Disseminated through the bloodstream to

Various organs cause swelling & Inflammation.

CLINICAL FEATURES OF MUMPS VIRUS INFECTION

⇒ The incubation period of this virus is 12-25 days.

⇒ Parotid swelling is usually the first sign of illness preceded by Malaise

⇒ It is accompanied by Fever, Local pain, and tenderness of parotid gland and Parotitis.

⇒ Epididymo-orchitis and Meningoencephalitis are important complications of Mumps.

⇒ Other less common complications are Arthritis, Oophoritis, Nephritis, Pancreatitis, Thyroiditis, and Myocarditis.

LABORATORY DIAGNOSIS OF MUMPS VIRUS

⇒ Specimen: Saliva, Throat secretions, CSF and Urine.

⇒ Direct Demonstration: Immunofluorescence on secretions of throat and saliva.

⇒ Isolation of the virus: Virus can be isolated from saliva, Throat swab, CSF or urine by inoculating into Primary monkey Kidney, HEp-2 or in Human Amnion.

⇒ Serology: Mumps specific IgM antibodies can be detected in serum by ELISA. Hemagglutination Inhibition Test and Neutralization Test can also be done.

PROPHYLAXIS OF MUMPS VIRUS

⇒ MMR, a live attenuated, vaccine is available. It can be administered subcutaneously and is a combination of attenuated Mumps, Measles and Rubella vaccine.

⇒ This vaccine is given to children aged 12-15 months.

⇒ It provides effective protection for at least 10 years.