measles teaching
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MEASLES basics
Dr.T.V.Rao MD
Dt.T.V.Rao MD 1
Early History of Measles
• Reports of measles go back to at least 700
years, however, the first scientific
description of the disease and its
distinction from smallpox attributed to the
Muslim physician Ibn Razi(Rhazes)
860-932 who published a book
entitled "Smallpox and Measles" (in
Arabic: Kitab fi al-jadari wa-al-
hasbah). Dt.T.V.Rao MD 2
Serious disease as Per WHO.
• It remains a leading cause of death among young children globally, despite the availability of a safe and effective vaccine. An estimated 197 000 people died from measles in 2007, mostly children under the age of five
Dt.T.V.Rao MD 3
Measles - Paramyxoviridae
• Measles is an infection
of the respiratory system
caused by a virus,
specifically a
Paramyxovirus of the
genus Morbillivirus
Morbilliviruses, like other
paramyxovirus, are
enveloped, single-
stranded, negative-sense
RNA viruses.
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Measles Virus
• The measles virus is a spherical, nonsegmented, single-stranded RNA virus in the Morbillivirus family, closely related to the rinderpest and canine distemper viruses. It contains six structural proteins, three that are complexed to the RNA and three that are associated with the viral membrane envelope. Dt.T.V.Rao MD 5
Fusion Protein
• The F (fusion) protein is responsible for fusion of virus and host cell membranes, viral penetration and haemolysis. The H (hem agglutinin) protein is responsible for adsorption of the virus to cells.
• There is only one serotype of Measles virus and no subtypes have yet been recognized
Dt.T.V.Rao MD 6
Measles
• More than 20 million people worldwide are affected by measles each year. Measles outbreaks are common in many areas, including Europe. For many U.S. travellers and expatriates, the risk for exposure to measles can be high, but the illness can be prevented by a measles-containing vaccine
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Spread of Measles
• Measles is spread through respiration
(contact with fluids from an infected
person's nose and mouth, either directly or
through aerosol transmission), and is
highly. The infection has an average
incubation period of 14 days (range 6-19
days) and infectivity lasts from 2-4 days
prior to 2-5 days following the onset of the
rash.
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Measles threat to Developing
World
• In developing
countries, measles
affects 30 million
children a year and
causes 1 million
deaths. Measles
causes 15,000-
60,000 cases of
blindness per year.
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Measles a Childhood Infection
• Age-specific attack rates may be highest in susceptible infants younger than 12 months, school-aged children, or young adults, depending on local immunization practices and incidence of the disease.
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Prominent features and
complications in Measles
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Patients on Physical
examination • Patients tend to appear moderately ill and
uncomfortable because of their viral prodromal symptoms.
• The Koplik spots are 1-2 mm, blue-gray macules on an erythematous base.
• The measles rash is a Maculopapular eythematous rash that involves the palms and soles.
• Lesion density is greatest above the shoulders, where macular lesions may coalesce
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Early Symptoms in Measles
• The incubation period from exposure to
onset of symptoms ranges from 8-12 days.
The prodromal phase is marked by
malaise, fever, anorexia,
and conjunctivitis, cough, and coryza
(the "3 Cs"). The entire course of
uncomplicated measles, from late
prodrome to resolution of fever and rash,
is 7-10 days. Cough may be the final
symptom to appear Dt.T.V.Rao MD 13
Beginning of Illness in
Measles • Approximately 10 days after the initial exposure
to the virus, the classic viral prodrome occurs.
• Fever
• Non-productive cough
• Coryza
• Conjunctivitis
• Additional prodromal symptoms may include
malaise, myalgia's, photophobia, and periorbital
oedema.
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A rash is leading
manifestations • Typically begins at the
hairline and spreads caudally over the next 3 days as the prodromal symptoms resolve.
• The rash lasts 4-6 days and then fades from the head downward.
• Desquamation may be present but is generally not severe.
• Complete recovery from the illness generally occurs within 7-10 days from the onset of the rash
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Koplik Spots leading clue to
Measles
• With in 2-3 days,
the pathognomonic
Koplik spots
typically arise on
the buccal,
gingival, and labial
mucosa
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Rash is a Prominent Feature
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Risk factors for infection
• Children with immunodeficiency due to HIV or acquired immunodeficiency syndrome (AIDS), leukaemia, alkylating agents, or corticosteroid therapy, regardless of immunization status
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Spread of Virus
• The highly
contagious virus is
spread by
coughing and
sneezing, close
personal contact or
direct contact with
infected nasal or
throat secretion
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Risk factors for severe
measles • Malnutrition
• Underlying
immunodeficienc
y
• Pregnancy
• Vitamin A
deficiency
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Mortality Rate in Measles
• The mortality rate
associated with
uncomplicated measles in
immunocompetent, well
nourished children is low
but raises rapidly with
malnourishment
(marked in African
children ), in
immunocompromised,
and to lesser extent with
age.
Dt.T.V.Rao MD 21
Modified Measles
• Modified measles occurs in children
who have received serum
immunoglobulin after their exposure
to measles. The measles symptom
complex may still occur, but the
incubation period is as long as 21
days, with the same symptoms as
measles but milder. Dt.T.V.Rao MD 22
Atypical Measles
• Atypical measles occurs in individuals who were previously immunized with the killed measles vaccine between 1963 and 1967 and who have incomplete immunity.
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Sub acute sclerosing panencephalitis
SSPE
• SSPE is a neurodegenerative disease
caused by persistent infection of the brain
by an altered form of the measles virus.
Neither the biology underlying the viral
persistence nor the triggering mechanism
for viral reactivation is well understood. In
most cases, infected children remain
symptom-free for 6-15 years after acute
measles infection[
Dt.T.V.Rao MD 24
Sub acute sclerosing
panencephalitis
• Subacute sclerosing panencephalitis (SSPE) 1 in 100,000 people infected with measles develop SSPE. SSPE is 'incurable' but the condition can be managed by medication if treatment is started at an early stage.
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Clinical Presentation of SSPE
• Characterized by a history of primary
measles infection usually before the age of
2 years, followed by several asymptomatic
years (6–15 on average), and then
gradual, progressive psycho neurological
deterioration, consisting of personality
change, seizures, myoclonus, ataxia,
photosensitivity, ocular abnormalities,
spasticity, and coma.
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Diagnosis of Measles
• Most cases of Measles are diagnosed clinically, usually in patient’s home or in General practice
• Direct Virological confirmation is difficult in most of the Developing countries
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Diagnosis with
Immunofluorescence
Direct and indirect immunofluorescence have been used extensively to demonstrate MV antigens in cells from NPS specimens.
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Diagnosis by Viral Isolation
• Measles virus can be isolated form a variety of sources, e.g. throat or conjunctival washings, sputum, urinary sediment cells and lymphocytes. Primary human kidney (HEK) cells are the best, although primary monkey kidney can be used as well. Continuous cell lines such as Vero cells can also be used
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Diagnosis by Serology
• Diagnosis of measles
infection can be made if
the antibody titres rise by
4 fold between the acute
and the convalescent
phase or if measles-
specific IgM is found. The
methods that can be used
include HAI, CF,
neutralization and ELISA
tests.
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Diagnosis of SSPE
• The presence of measles specific antibodies in the CSF is the most reliable means of laboratory diagnosis of SSPE. Demonstration of MV-specific antibodies in the CSF may be sufficient with,
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Epidemiological Trends
• Measles epidemics
occur every 2 year in
developed countries
in the absence of
widespread use of
vaccine
• Poverty and
overcrowding
increases epidemics
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Treatment
• Severe complications from measles can be avoided though supportive care that ensures good nutrition, adequate fluid intake and treatment Antibiotics should be prescribed to treat eye and ear infections, and pneumonia.
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VACCINATION
• The Vaccines are Live attenuated containing Edmonston B or Schwartz strains which will give seroconversion rate of 90%.
• The immunity produce may be life long.
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Measles vaccine is given as
MMR Vaccine
• The measles vaccine is
often incorporated with
rubella and/or mumps
vaccines in countries
where these illnesses are
problems. It is equally
effective in the single or
combined form.
• The combination
proved to be
effective and safe
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Two doses of Measles
Vaccine • Continued progress
depends on ensuring
that all children
receive two doses of
measles vaccine
including one dose by
their first birthday,
strengthening disease
surveillance systems,
and providing
effective treatment for
measles. Dt.T.V.Rao MD 36
Changing trends for a Booster
Dose
• About 15% of
vaccinated
children fail to
develop
immunity
from the first
dose.
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paramedical students in
Developing world
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