Detail description of Measles, Mumps and Rubella virues

1. AMAN ULLAH
Mumps, Measles and Rubella

2. Mumps, Measles and Rubella viruses
 The viruses to be described in this chapter are
genetically unrelated
 However, they share several common epidemiologic
characteristics
1. Distribution is worldwide, with a high incidence of
infection in non immune individuals
2. Humans appear to be the sole reservoir of infection
3. Person-to-person spread is primarily by the
respiratory (aerosol) route

3. Mumps & Measles viruses
Common characteristics of Mumps and Measles
 Members of Paramyxoviridae
 Non segmented, negative-strand RNA
 Helical enveloped viruses
 Envelope contains two types of integral membrane or
envelope proteins
 HN protein (H stands for hemagglutinin and N for
neuraminidase), is involved in the binding of the virus to a
cell
 F (fusion) protein that allows virus to enter cells via a
fusion process, rather than by receptor mediated
endocytosis
 Measles virus lacks the neuraminidase activity

4. Mumps virus
Epidemiology
 highest frequency of mumps infection is observed in
the 5- to 15-year age group
 virus spreads by respiratory droplets
Pathogenicity and clinical findings
 Mumps virus replicates in the upper respiratory tract
and in regional lymph nodes and spreads via the
blood to distant organs
 Infection can occur in many organs, but the most
frequently involved is the parotid gland.

5. Mumps virus
Pathogenicity cont…
 After an incubation period of 12 to 29 days (average, 16 to 18
days), the typical case is characterized by fever and swelling
with tenderness of the salivary glands, especially the parotid
glands
 Swelling may be unilateral or bilateral and persists for 7 to 10
days
 The testes are also frequently infected
 About 25% of infected males who have reached puberty can
develop orchitis. The testes enlarge and stretch the capsule,
resulting in intense pain
 Infertility is a rare complication
 Meningitis and encephalitis can also occur
 live attenuated viral vaccine is a part of the trivalent measles
mumps rubella (MMR) vaccine

6. Mumps virus
Diagnosis
 The usual serologic tests are enzyme immunoassay (EIA) and
indirect immunofluorescence to detect IgM- and IgG-specific
antibody responses
Prevention
 Since 1967, a live attenuated vaccine that is safe and highly effective
has been available
 It is commonly combined with measles and rubella vaccines (MMR)
and given as a single injection at 12 to 15 months of age
 A second dose of MMR is recommended at 4 to 6 years of age; those
who have missed the second dose should receive it no later than 11
to 12 years of age
 Duration of immunity, especially if the two-dose regimen is
followed, appears to be more than 25 years and may be lifelong

7. MEASLES VIRUS

8. Measles virus
Transmission
 Measles virus is highly contagious and spreads through
nasopharyngeal secretions by air or by direct contact
 The virus is extremely infectious, and almost all infected
individuals develop a clinical illness
Pathogenicity and clinical findings
 Incubation period is 7–18 days
 Prior to the appearance of the rash, the patient suffers
from prodromal illness with conjunctivitis, swelling of
the eyelids, high fevers to 105° F, cough, rhinitis, and
malaise

9. Measles virus
Pathogenicity cont…
 A day or 2 before the rash, the patient develops small
red-based lesions with blue white centers in the
mouth called Koplik's spots
 And a generalized macular rash appears, beginning
at the head and traveling slowly to the lower
extremities
 Soon after the rash appears, the patient is no longer
infectious
 The rash disappears in the same sequence as it
developed after 3to 5 days persistence

10. Measles virus
Complications
 measles virus disseminates to many organ systems
and can damage those sites, causing pneumonia, eye
damage, heart involvement (myocarditis), and the
most feared complication, encephalitis
 Many years after a measles infection the child or
adolescent may have slowly progressing central
nervous system disease, with mental deterioration
and incoordination

11. Measles virus
Diagnosis
 The typical measles infection can often be diagnosed
on the basis of clinical findings
 Rapid diagnosis is possible by immunofluorescence
Prevention
 The MMR vaccine, which contains live attenuated
measles virus, is preventative
 The vaccine should be administered to infants at 12
to 15 months of age with a second dose at 4 to 6 or 11
to 12 years of age

12. Rubella virus

13. Rubella virus
Common characteristics
 Positive-strand, single-stranded, nonsegmented
RNA genome
 Enveloped, icosahedral nucleocapsid
 Genomic RNAs serve as messenger RNAs and are
infectious

14. Rubella virus
Pathogenesis/Clinical Significance
 The virus is transmitted via respiratory secretions from
an infected individual
German measles
 This is a mild clinical syndrome (not to be confused
with rubeola, caused by the measles virus). The
infection is characterized by a generalized
maculopapular rash and occipital lymphadenopathy
 In most cases, these symptoms may be hardly
noticeable, and the infection remains subclinical

15. Rubella virus
Congenital rubella
 The major clinical significance of rubella is that
when a pregnant woman is infected with the virus,
there can be significant damage to the developing
fetus, especially in the first trimester
 This damage can include congenital heart disease,
cataracts, hepatitis, and abnormalities related to the
central nervous system, such as mental retardation,
motor dysfunction, and deafness

16. Rubella virus
Treatment
 No antiviral drugs are currently in use
Prevention
 Fetal damage due to rubella infection is preventable by
use of the live, attenuated rubella vaccine that is included
with the routine childhood vaccinations
 This vaccine is effective, has few complications, and
ensures that when women reach childbearing age, they
are immune to rubella infection
 The vaccine should not be given to women who are
already pregnant or to immunocompromised patients,
including young babies

17. Rubella virus
Laboratory diagnosis
 A diagnosis of rubella infection can be made by
measuring a rise in antibody titer
 Pregnant women with antirubella IgM antibody are
presumed to have been recently exposed to the virus