Measles, Mumps & Rubella (MMR)

• Infections with measles, mumps and rubella viruses are confined to man and occur worldwide.

• Spread primarily via the aerosol route. • Each of these viruses exists as a single serotype• MMR vaccine contains all three of these viruses• .Measles & Mumps belong to family

Paramyxovirus• RNA enveloped viruses

Measles & Mumps

MEASLES (RUBEOLA) PATHOGENESIS AND DISEASE

• The word measles is derived from German word for blister

• Respiratory droplet infection. • Virus replicates in the upper/lower respiratory tract and

lymphoid tissues leading to viremia and then growth in a variety of epithelial sites.

• The virus is very contagious: maximum contagiousness is 2 to 3 days before onset of the rash.

• The disease develops 1 - 2 weeks after infection.

Clinical Features• Measles is still a major killer in

underdeveloped countries • Fever of 101oF (38.3o C) or above• Running nose (coryza) and cough• Conjunctivitis• Koplik's spots on mucosal

membranes - small (1 - 3mm), irregular, bright red spots, with bluish-white speck at center.

• Maculopapular rash which extends from face to the extremities.

• The infection is prostrating but recovery is usually rapid

Clinical Features

Complications of Measles

• Secondary bacterial infections: otitis media and bacterial pneumonia.

• Pneumonia accounts for 60% of deaths from measles

• Encephalitis (1 in 1000 cases) a few days after the rash disappears.

Subacute Sclerosing Pan encephalitis• Very rare (7 in 1,000,000 cases) • Develops 1 to 10 years after the initial infection. • Behavioral changes. • Impaired speech, vision and swallowing • A progressive, usually fatal disease • SSPE is associated with defective forms of the

virus in the brain

Complications of Measles

• Measles can cause temporary defects in the immune response; e.g. tuberculin-positive individuals may temporarily give a negative response.

Complications of Measles

LAB DIAGNOSIS

• The clinical picture • Serodiagnosis

o IgM & IgG levels

• Virus isolation in cell cultureo The large syncytia, or multinucleated

giant cells, result from fusion of cell membranes

o Inclusion bodies,  eosinophilic areas of altered staining in the cytoplasm

EPIDEMIOLOGY• Almost all infected individuals show signs

of disease. • Only one serotype of measles and a single

natural infection gives life-long protection.

MMR Vaccine • Is a live, attenuated combined vaccine to

prevent measles, mumps and rubella. • Two doses are given to pre-school

children: o The first dose at 12-15 months o The second booster dose at 3-5 years

PREVENTION

PREVENTION & TREATMENT

• Immune serum globulin: for at risk patients during an outbreak i.e. those <1 year with impaired cellular immunity

o No antiviral therapy available for primary disease. Complications should be treated appropriately

MUMPS

• The name comes from the British word "to mump", that is grimace

• Clinically, mumps is an acute unilateral or bilateral parotid gland swelling that lasts for more than two days with no other apparent cause.

Other agents can also cause parotitis

Mumps Pathogenesis

Mumps Epidemiology

Reservoir Human

Transmission Respiratory droplet infection

Communicability 7 days before to 9 days after

onset of active disease

• Worldwide distribution

•Many (30%) infections are sub-clinical

•No 'carrier state'.

Clinical Aspects of Mumps

• Fever• Parotitis• Meningitis & encephalitis• Orchitis• Pancreatitis • Myocarditis• Nephritis• Arthritis

Mumps Complications

CNS involvement 15% of clinical cases

Orchitis 20-50% in

post-pubertal males

Pancreatitis 2-5%

Deafness 1/20,000

Death 1-3/10,000

MMR Vaccine • Is a live, attenuated combined vaccine to

prevent measles, mumps and rubella. • Two doses are given to pre-school

children: o The first dose at 12-15 months o The second booster dose at 3-5 years

PREVENTION & TREATMENT

Rubella (German Measles)

History

1881Rubella accepted as a distinct disease 1941Associated with congenital disease

Rubella virus first isolated 1961 1967Serological tests available

1969Rubella vaccines available

Rubella Virus

RNA enveloped virusMember of the togavirus family

Spreads by respiratory droplets In the pre-vaccination era, 80% of women were already infected by childbearing age

Clinical Features

Rubella: Latin “little red”Maculopapular rash

Lymphadenopathy

Fever

Arthropathy (up to 60% of cases)

Rash of Rubella

Risks of Rubella Infection During Pregnancy

Preconception :Minimal risk

0-12 weeks: 100% risk of fetus being congenitally infected

  resulting in major congenital  abnormalities. Spontaneous abortion occurs in 20% of cases .

13-16 weeks: Deafness and retinopathy 15% After 16 weeks: Normal  development, slight risk of

deafness and retinopathy

Congenital Rubella Syndrome

Classical triad consists of:

CataractsHeart defects Sensorineural deafness .

TransientLow birth weight, hepatosplenomegaly, thrombocytopenic purpura, meningoencephalitis, hepatitis, haemolytic anemia, pneumonia, lymphadenopathy

PermanentSensorineural deafness, Heart defects, Eye defects (retinopathy, cataract, microopthalmia, glaucoma), diabetes mellitis

DevelopmentalSensorineural deafness, Mental retardation

Congenital Rubella Syndrome

Outcome

1/3 rd will lead normal independent lives

1/3 rd will live with parents

1/3rd will be institutionalised

The only effective way to prevent CRS is to terminate the pregnancy

Laboratory Diagnosis

Diagnosis of acute infectionPresence of rubella-specific IgM

Rising titres of antibody (mainly IgG)

Typical Serological Events following acute rubella infection

Note that in reinfection, IgM is usually absent or only present transiently at a low level

Prevention

Antenatal screening

Screening of all pregnant women attending antenatal clinics for immune status against rubella.

Non-immune women are vaccinated in the immediate post partum period.

Prevention

Since 1968, a highly effective live attenuated vaccine has been available with 95% efficacy

Universal vaccination is now offered to all infants as part of the MMR regimen in the USA, UK and a number of other countries.

Vaccination of schoolgirls before they reach childbearing age.