MEASLES

By Dr. sukhwant

singh

INTRODUCTION

*Measles, an acute viral exanthematous fever caused by Morbillivirus.*It is a leading cause of childhood deaths in developing countries, * Measles is one of the most contagious diseases known. *Almost all non – immune children contract this respiratory disease if exposed to the virus.*It is a human disease not known to occur in animals

*Before the development of safe and effective vaccines, measles was responsible for approximately six million deaths of infants and children globally every year. *As measles vaccination has become more and more widespread, there has been a marked decline in measles particularly in developed countries.

*The largest proportional reduction in deaths due to measles has occurred in the African Region accounting for 70% of the global reduction in measles mortality.

*98% of deaths due to measles occur in developing countries because it is 100-400 times more likely to cause death in pre school children with malnutrition.

*Case - fatality rates in these countries are normally in the range of 1 to 5% but may reach as high as 10 to 30% in populations with high levels of malnutrition and poor access to health care.

* Despite these advances, however, an estimated 20 million cases of measles resulted in 242,000 deaths in 2006.

WHO defines elimination of Measles as-

Absence of endemic measles for a period of > 12 months.

Indicator of Measles elimination :A sustained measles incidence < 1/10

Lac population.World Health Assembly has set a goal of achieving 90 percent reduction in global measles mortality by 2010 as

compared with levels in 2000.

INDIA Before the introduction of measles vaccine -* An estimated 100,000 cases of measles occurred each year in the country with outbreaks at an interval of about 3 years. After the introduction of measles vaccination,as part of the National Immunization Schedule in 1985

* The number of cases has decreased and the interval between outbreaks has also increased to about 5 years. *The number of reported cases of measles in India has declined from 162,560 in 1989 to 51,546 in 2004.

AGENT

*Genus Morbillivirus *Family paramyxoviridae. *The virus is a non segmented, enveloped, negative sense single stranded RNA virus. *Measles virus particles are pleomorphic spheres with diameter ranging from 100 nm to 250 nm.

* The virus can not survive outside the human body .

* It can, however, remain viable in droplets for several hours.

* It can retain the infectivity when stored at sub zero temperature.

*measles virus is easily destroyed by drying, exposure to sunlight and acids.

*Humans are the only natural hosts for the virus.

* The virus can be grown in cell cultures.

*There is only one serotype.

SOURCE OF INFECTION* A case of measles.

* Carriers are not known to occur.

INFECTIVE MATERIAL* Secretions of the nose, throat and

respiratory tract of a case of measles during the prodromal period and the

early stages of the rash.

COMMUNICABILITY* The period of communicability is approximately 4 days before and 5 days after the appearance of rash.* Isolation of the patient for a week from the onset of rash covers the period of communicability.* Measles is highly infectious during the prodromal period and at the time of eruption. ( Secondary Attack Rate – 90% )

HOST FACTORS

AGE Susceptibility to infection is universal in those not exposed irrespective of age.

However, most infections occurin the age group 6 months to 3 years in

developing countries. And older children usually over 5 years

in developed countries.

IMMUNITY

*No age is immune if there was no previous immunity.

* Infants are protected by maternal antibodies up to 6 months of age.

* One attack of measles confers life long immunity, because there is only one serotype of the virus.

NUTRITION*Measles is very severe in malnourished with mortality up to 400 times higher than well nourished children. *It can precipitate Kwashiorkor in borderline cases. *Persons with malnutrition, especially vitamin A deficiency, or with severe immunological disorders such as advanced HIV infection are at increased risk of developing severe or even fatal measles.

ENVIRONMENT

*In India, the peak incidence of measles is in winter and early spring.

( January to April )

*In temperate countries most casesoccur in winter months.

*Overcrowding favors transmission.

TRANSMISSION

* Transmission occurs directly from person to person by droplet infection

and droplet nuclei.* Infection through conjunctiva is also

considered likely.* Recipients of measles vaccine are

not contagious to others.

PERIOD OF COMMUNICABILITY

* Ranges from 4 days before onset of rash until 5 days thereafter.

* Portal of entry is respiratory tract.

INCUBATION PERIOD

* 10 days from exposure to fever and 14 days to appearance of rash.

* When infection is artificially induced by-passing the respiratory tract ( as with administration of live vaccine ),

the incubation period is shortened, averaging 7 days.

PRESENTATION

1. PRODROMAL STAGE :* Begins 10 days after infection, and lasts until day 14.* Characterized by- - Fever, Malaise, Cough - Coryza, Nasal discharge - Redness of eyes, Lacrimation, Photophobia. - Vomiting / Diarrhea.

Koplik’s spots –

*They are small, bluish white spots on a red base seen on the buccal mucosa opposite the first and second lower molars.

* They appear one or two days before the appearance of rash.

* Their presence is pathognomonic of measles.

2. ERUPTIVE PHASE -

*This phase is characterised by typical dusky red, maculo-papular rash, which begins behind the ears and spreads over the face and neck.* It extends down the body taking 2-3 days to progress to lower extrimities.* The rash may remain discrete, or become confluent and blotchy.* The rash fades in another 3 or 4 days in the same order of appearance leaving a brownish discoloration persisting for 2 months or more.

* During the prodromal phase (2-4 days ) and the first 2-5 days of rash, virus is present in tears, nasal and throat secretions, urine and blood.

* Appearance of maculo-papular rash coincides with detectability of circulating antibodies.

* No rash develops in patients with defective cell mediated immunity.

3.POST MEASLES STAGE

* The child will have lost some weight and will remain week for a number of days.

* There may be failure to recover and a gradual deterioration in to chronic illness.

* There may be growth retardation, diarrhea, cancrum oris, pyogenic infections, candidosis, reactivation of pulm. Tuberculosis etc.

COMPLICATIONS

* Otitis media* Pneumonia* Blindness ( Due to acute deficiency of vit-A )

* SSPE ( Occurs at an average of 7 years after initial infection)

* Pregnancy – Spontaneous abortion - Premature delivery

TREATMENT

* Outbreaks of measles must be reported

to local health authorities. * Respiratory isolation may be indicated for 6-7 days after appearance of rash.

* Exclusion from school is required for one week from appearance of rash to avoid

contact with susceptibles.

* In hospital strict isolation of cases is essential. *Articles soiled by secretions or fluids from

vesicles to be incinerated or treated with disinfectants.

VITAMIN – A IN

MEASLES

*All children in developing countries diagnosed with measles should receive two doses of vitamin A supplements given 24 hours apart.

*This can help prevent eye damage and blindness.

*Vitamin A supplementation has been shown to reduce the number of deaths from measles by 50%.

*Supplementary dosage is : - Infants 6 - 11 months - 1,00,000 IU - Children 12 months and over - 2,00,000 IU.

PREVENTION

*A live attenuated vaccine against measles has

been available since 1966. * In INDIA, measles vaccine included in UIP in 1985.*A number of strains like the Edmonston B strain, Schwarz strain and Moraten strain are used in vaccine manufacture.* The vaccine is presented as freeze dried product ( Must be stored in freezer compartment )

*In India, a single dose of 0.5 ml SC is given at nine months of age. (Edmonston B strain)

*In developed countries two doses are given, The first dose at 12 to15 months followed by a second dose at 4 to 5 years of age.

* The reconstituted vaccine should be kept on ice and used within 1 hour.

: REACTION : * When injected in to the body, measles virus multiplies and induces a mild measles illness (fever & rash) 5 to 10 days after immunization, but in reduced frequency and severity.

* This may occur in 15-20 percent of vaccinees.

* Fever may last for 1-2 days and rash for 1-3 days.

IMMUNITY * Immunity develops 11 to 12 days after vaccination.* Immunity is probably for life long.* One dose of measles vaccine appears to give 95 percent protection.* Susceptible contacts of 9-12 months of age may be protected by giving vaccine within 3 days of exposure.

CONTRAINDICATIONS* Pregnancy

* Deficient cell mediated immunity* Use of immunosuppressive drugs

and steroids.

ADVERSE EFFECTS* Toxic Shock Syndrome

Watery diarrhea, Vomiting & High feverOccurs with contaminated vaccine

COMBINED VACCINE

Measles vaccine can be combined with other live attenuated

vaccines-Mumps and Rubella as

MMRSuch combinations are also highly

effective

Measles Vaccine

MMR Vaccine

IMMUNOGLOBULIN

*It should be given within 3 – 4 days of exposure.

* Dose- 0.25 ml/kg body weight.

* Persons passively immunized should be given live measles

vaccine 8-12 weeks later.