Measles Basics

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Early History of Measles

Reports of measles go back to at least 700

years, however, the first scientificdescription 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" (inArabic: Kitab fi al-jadari wa-al-

hasbah).Dt.T.V.Rao MD 2


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Serious disease as Per WHO.

It remains a leadingcause of deathamong young childrenglobally, despite theavailability of a safeand effective vaccine.An estimated 197 000people died from

measles in 2007,mostly children underthe age of five

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Measles - Paramyxoviridae

Measles is an infectionof the respiratory systemcaused by a virus,specifically a

Paramyxovirus of thegenus MorbillivirusMorbilliviruses, like otherparamyxovirus, are

enveloped, single-stranded, negative-senseRNA viruses.

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Measles Virus

The measles virus is aspherical,nonsegmented, single-stranded RNA virus in

the Morbillivirusfamily,closely related to therinderpest and caninedistemper viruses. Itcontains six structural

proteins, three that arecomplexed to the RNAand three that areassociated with theviral membrane

envelope. Dt.T.V.Rao MD 5


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Fusion Protein

The F (fusion) protein isresponsible for fusion ofvirus and host cellmembranes, viral

penetration andhaemolysis. The H (hemagglutinin) protein isresponsible for adsorptionof the virus to cells.

There is only oneserotype of Measles virusand no subtypes have yetbeen recognized

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Measles

More than 20 millionpeople worldwide areaffected by measles eachyear. Measles outbreaks

are common in manyareas, including Europe.For many U.S. travellersand expatriates, the riskfor exposure to measles

can be high, but theillness can be preventedby a measles-containingvaccine

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Spread of Measles

Measles is spread through respiration

(contact with fluids from an infectedperson's nose and mouth, either directly or

through aerosol transmission), and ishighly. The infection has an averageincubation period of 14 days (range 6-19

days) and infectivity lasts from 2-4 daysprior to 2-5 days following the onset of therash.

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Measles threat to DevelopingWorld

In developing

countries, measlesaffects 30 million

children a year andcauses 1 milliondeaths. Measles

causes 15,000-60,000 cases ofblindness per year.

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Measles a Childhood Infection

Age-specific attackrates may be highestin susceptible infantsyounger than 12months, school-agedchildren, or youngadults, depending onlocal immunization

practices andincidence of thedisease.

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Prominent features andcomplications in Measles

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Patients on Physicalexamination

Patients tend to appear moderately ill anduncomfortable because of their viral prodromalsymptoms.

The Koplik spots are 1-2 mm, blue-gray maculeson an erythematous base.

The measles rash is a Maculopapulareythematous 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 lateprodrome to resolution of fever and rash,is 7-10 days. Cough may be the final

symptom to appearDt.T.V.Rao MD 13


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Beginning of Illness inMeasles

Approximately 10 days after the initial exposureto the virus, the classic viral prodrome occurs.

Fever

Non-productive cough

Coryza

Conjunctivitis

Additional prodromal symptoms may includemalaise, myalgia's, photophobia, and periorbitaloedema.

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A rash is leadingmanifestations

Typically begins at the

hairline and spreadscaudally over the next 3days as the prodromalsymptoms resolve.

The rash lasts 4-6 daysand then fades from thehead downward.

Desquamation may be

present but is generallynot severe.

Complete recovery fromthe illness generallyoccurs within 7-10 daysfrom the onset of the rashDt.T.V.Rao MD 15


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Koplik Spots leading clue toMeasles

With in 2-3 days,

the pathognomonicKoplik spots

typically arise onthe buccal,gingival, and labial

mucosa

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Rash is a Prominent Feature

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Risk factors for infection

Children withimmunodeficiencydue to HIV oracquiredimmunodeficiencysyndrome (AIDS),leukaemia, alkylatingagents, or

corticosteroid therapy,regardless ofimmunization status

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Spread of Virus

The highly

contagious virus isspread by

coughing andsneezing, closepersonal contact or

direct contact withinfected nasal orthroat secretion

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Risk factors for severemeasles

Malnutrition

Underlying

immunodeficiency

Pregnancy

Vitamin Adeficiency

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Mortality Rate in Measles

The mortality rateassociated withuncomplicated measles inimmunocompetent, well

nourished children is lowbut raises rapidly withmalnourishment(marked in African

children ), inimmunocompromised,and to lesser extent withage.

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Modified Measles

Modified measles occurs in children

who have received serum

immunoglobulin after their exposureto measles. The measles symptom

complex may still occur, but the

incubation period is as long as 21days, with the same symptoms as

measles but milder.

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Atypical Measles

Atypical measlesoccurs inindividuals whowere previouslyimmunized withthe killed measlesvaccine between1963 and 1967and who haveincompleteimmunity.

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Sub acute sclerosing panencephalitisSSPE

SSPE is a neurodegenerative diseasecaused by persistent infection of the brainby an altered form of the measles virus.

Neither the biology underlying the viralpersistence nor the triggering mechanismfor viral reactivation is well understood. In

most cases, infected children remainsymptom-free for 6-15 years after acutemeasles infection[

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Sub acute sclerosingpanencephalitis

Subacute sclerosingpanencephalitis(SSPE) 1 in 100,000people infected withmeasles developSSPE. SSPE is'incurable' but thecondition can be

managed bymedication iftreatment is started atan early stage.

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Clinical Presentation of SSPE

Characterized by a history of primary

measles infection usually before the age of2 years, followed by several asymptomatic

years (615 on average), and thengradual, progressive psycho neurologicaldeterioration, consisting of personality

change, seizures, myoclonus, ataxia,photosensitivity, ocular abnormalities,spasticity, and coma.

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Diagnosis of Measles

Most cases ofMeasles arediagnosed clinically,usually in patients

home or in Generalpractice

Direct Virologicalconfirmation is difficultin most of theDeveloping countries

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Diagnosis withImmunofluorescence

Direct andindirectimmunofluores

cence havebeen usedextensively to

demonstrateMV antigens incells from NPS

specimens.Dt.T.V.Rao MD 28


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Diagnosis by Viral Isolation

Measles virus can beisolated form a varietyof sources, e.g. throator conjunctivalwashings, sputum,

urinary sediment cellsand lymphocytes.Primary human kidney(HEK) cells are the best,although primarymonkey kidney can beused as well.Continuous cell linessuch as Vero cells canalso be used

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Diagnosis bySerology

Diagnosis of measlesinfection can be made ifthe antibody titres rise by4 fold between the acute

and the convalescentphase or if measles-specific IgM is found. Themethods that can be used

include HAI, CF,neutralization and ELISAtests.

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Diagnosis of SSPE

The presence ofmeasles specificantibodies in the CSFis the most reliable

means of laboratorydiagnosis of SSPE.Demonstration of MV-specific antibodies in

the CSF may besufficient with,

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Epidemiological Trends

Measles epidemicsoccur every 2 year indeveloped countries

in the absence ofwidespread use ofvaccine

Poverty and

overcrowdingincreases epidemics

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Treatment

Severe complications frommeasles can be avoided though

supportive care that ensures goodnutrition, adequate fluid intakeand treatment Antibiotics should

be prescribed to treat eye and earinfections, and pneumonia.

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VACCINATION

The Vaccines areLive attenuatedcontainingEdmonston B orSchwartz strainswhich will giveseroconversionrate of 90%.

The immunityproduce may belife long.

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Measles vaccine is given asMMR Vaccine

The measles vaccine isoften incorporated withrubella and/or mumpsvaccines in countries

where these illnesses areproblems. It is equallyeffective in the single orcombined form.

The combinationproved to beeffective and safe

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Two doses of MeaslesVaccine

Continued progressdepends on ensuringthat all children

receive two doses ofmeasles vaccineincluding one dose bytheir first birthday,

strengthening diseasesurveillance systems,and providingeffective treatment for

measles. Dt.T.V.Rao MD 36


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Changing trends for a BoosterDose

About 15% ofvaccinated

children fail todevelopimmunity

from the firstdose.

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Measles Basics

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