MUMPS

INTRODUCTION: Mumps is predominantly, but not exclusively, a disease of childhood. Attacks in adult life are probably much more frequent than of measles, chickenpox and other common infections. No age is immune and there is no difference in the incidence between the two sexes although the disease appears to be more frequent in young male adults than in females. This difference is perhaps more apparent than real and due mainly to high incidence of orchitis which draws attention to what might otherwise be a short and soon-forgotten illness. Like measles mumps virus is a member of the family Paramyxoviridae.

PATHOGENESIS: Mumps is a typical systemic viral infection. The portal of entry of the virus is thought to be the upper respiratory tract. The time interval after exposure to virus before the appearance of the clinical features ranges from 14 to 21 days, with the usual incubation period being 16-18 days. After entering the host, the virus replicates and viraemia results. It leads to secondary invasion of several organs. Tissues such as the salivary glands (predominantly the parotids), meninges, testes, pancreas, ovaries, thyroid and heart may show evidence of infection. Virus is also excreted in urine and transient abnormalities in renal functions have been found.

Pathogenesis of damage to nervous system is poorly understood but may be due to direct lysis of cells and immunopathological mechanisms. All classes of specific immunoglobulins are induced by primary infection due to mumps virus. The IgM response persists for a few days but the IgG response is life-long. [Readabout immunoglobulins]

CLINICAL FEATURES: Mumps is a common contagious disease of children and young adults. It is characterised by the inflammation of salivary glands. Bilateral involvement of parotid glands is the commonest occurrence. Unilateral involvement of this gland can also occur. Similarly inflammation and swelling of submaxillary glands as well as sublinguals can also get infected. The disease is considered more notorious because of its complications of which orchitis and sterility in adult males is important. Infection with mumps virus during the first trimester of pregnancy may result into abortion. Though no teratogenicity has been demonstrated because of this virus, ample evidence for transplacental transmission is available.

LABORATORY DIAGNOSIS: In the presence of typical clinical picture the diagnosis of mumps is very simple and does not require any support from the laboratory. However, diagnosis by the virus isolation or serological techniques is most useful when the patient presents with an atypical or asymptomatic infection.

Clinical Specimens: Virus isolation from the spinal fluid, blood, saliva and urine confirms the diagnosis of recent mumps infection.

Isolation of the Virus Primary monkey kidney cell cultures are the most sensitive substrates for the isolation of this virus. These cells may be of rhesus or cynomolgus monkey origin. Continuous human cell lines such as HeLa and primary cell cultures of human amnion or human embryonic kidney can also be used for the growth of the virus. The virus produces a characteristic cytopathic effect (CPE) with large syncytia. Some strains may not produce CPE and their adsorption with guinea pig erythrocytes should be attempted to identify them. Rapid identification of mumps isolates can be achieved by immunofluorescence staining.

Serodiagnosis: Serological diagnosis of mumps infection can be very important, especially in those cases of meningitis or encephalitis that occur in the absence of parotitis. Serological methods for the diagnosis of mumps infection include complement fixation, haemagglutination inhibition, neutralisation, and ELISA. Use of ELISA to detect IgM is particularly suitable for early diagnosis of mumps infection with one serum specimen.

Treatment and Prevention: A live attenuated vaccine prepared from Jeryl Lynn strain of mumps virus was licensed for human use in the USA in 1967 and since then more than 100 million doses have been administered to children. Till recent past vaccines were prepared from following strains of mumps virus: Jeryl Lynn strain, Urabe strain, Rubini strain However, a higher incidence of vaccine associated meningitis because of the vaccine prepared from Urabe strain has forced the authorities in United Kingdom and Europe to discontinue the use of mumps vaccine prepared from this strain. The other two strains have not exhibited this kind of adverse reactivity. Mumps vaccine can be given along with or in combination with antigens of measles and rubella in combined form of measles-mumps-rubella (MMR). There is no specific treatment.

RELATED;

1. INTRODUCTION TO VIROLOGY  

2. HEMORRHAGIC FEVER VIRUSES  

3. VIRAL HEPATITIS

4.  MEDICAL MICROBIOLOGY

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