د انمار الديوجي Measles

Measles

Measles is one of the most contagious infectious diseases Caused by the measles virus, which is RNA virus, a member of the family paramyxoviridae, genus Morbillivirus.


Epidemiology Approximately 17 million measles cases and 242000 deaths worldwide in 2006 . Over 80% reported cases are from southeast Asia and Africa. Over 85% in children aged <5 years. In temperate climates, it occurs in late winter and late spring. In tropical climates, it occurs primarily in dry season

Epidemiology

Race: Measles affects people of all races. Sex: Excess mortality following acute measles has been observed among females at all ages, but it is most marked in adolescents and young adults.

Epidemiology

Age: affect everyone in infancy or childhood between 6m-3 years in developing countries and children > 5years in developed countries . Following the use of measles vaccine ,the disease now seen in older age groups

Epidemiology

Prior to widespread immunization It was a common childhood disease. There were an estimated 100 million cases and 6 million death each year. It was endemic in large communities attained epidemic proportion every 2 or 3 years. In small communities epidemics tended to be more widely spaced and more severe.


Epidemiology Effect of routine vaccination on the epidemiology of measles Reduction of the incidence by 99% in many developed countries. Reduction of the CFR. Cases appeared among young unimmunized children or older children, adolescents or young adults who received one dose.

Risk factors for infection

Children with immunodeficiency due to HIV or AIDS, leukemia, alkylating agents, or corticosteroid therapy, regardless of immunization status. Travelers to areas where measles is endemic or contact with travelers to endemic areas. Infants who lose passive antibody prior to the age of routine immunization

Risk factors for severe measles

Malnutrition Underlying immunodeficiency Pregnancy Vitamin A deficiency (clinical and sub clinical) Infants and adults



Chain of events


Reservoir Human Mode of transmission Direct droplet Air borne Direct contact with nasal or throat discharge. Articles soiled with nose & throat secretion (less common).

Chain of events

The incubation period ranges from 8-12 days

Chain of eventsPeriod of communicability

Chain of events Susceptibility & resistance


Acquired immunity after illness is permanent. Immunization at 12-15 months induced immunity in 94-98% of recipients. There is maternal immunity (6-9 months) depending on: Amount of residual maternal antibodies at the time of pregnancy . Rate of antibody degradation

Chain of events Susceptibility & resistance

Maternal antibodies interfere with the response to vaccination Re immunization increases immunity level to about 99%.

Clinical features

Incubation period ranges from 8-12 days Prodromal stage: (last 3-5 days) fever, malaise ,rhinorrhea, conjunctivitis, Koplik spots (small grey irregular lesions surrounded by erythematous base appears on buccal and pharyngeal mucosa).

Clinical features

Rash (last 5 days) Macculopapular rash started behind ears, face, and neck and then progress to involve the whole body ,arms and legs in spreading manner. Rash usually associated with high fever (temp 39-40 C) Rash usually disappear in the same manner (this usually last 7-10 days)

Clinical features

Clinical Characteristics Complications Otitis media Interstitial pneumonitis, Bronchopneumonia and croup Dehydration and diarrhoea Blindness Sever skin infection. Approximately 1 of every 1,000 patients develops acute encephalitis

Clinical Characteristics Complications

Rare complication include hemorrhagic measles, and protein losing enteropathy. Sub acute sclerosing pan encephalitis (SSPE) (1/100 000 cases) developed several years after infection. Exacerbation of tuberculosis. Encephalomyelitis.

Diagnosis

Prevention


Public education Immunization Live attenuated vaccine indicated to all persons not immune to measles ,unless otherwise contra-indicated. Single injection of measles vaccine (MMR) which can be administrated concurrently with other inactivated vaccines or toxoid induces active immunity in 94-98% of susceptible (life long) 2 nd dose increases the immunity level to as high as 99%.


Prevention Side effects 5-15 % fever ,malaise within 5-12 days after immunization, lasts 1-2 days. Occasionally rash, coryza, Koplik spots. Infrequently febrile seizures . 1:10 6 dose Encephalitis & encephalopathy

Prevention

In developed countries To reduce the no. of vaccination failure : 1st dose at 12-15 months. 2nd dose at 4-6 years Or It must be given after one month after the first dose where the risk of exposed is high. Both doses are generally given as MMR

Optimal age of vaccination

WHO recommend immunization at 9 months of age Immunization before the age of 9 months run the risk the vaccine being rendered ineffective by natural antibodies through mother. Age of vaccination can be lowered to 6 months if there is measles outbreak. For infants immunized between 6-9 months, second dose should be gives as soon as possible after the child reach age of 9 months.

Contra-indication of vaccination

PT with primary immune deficiency disease affecting T-cell functions, or acquired immunodeficiency except HIV. Sever illness with or without fever, Delay the dose until recovery. minor illnesses such as diarrhea , upper respiratory infections are not a contra-indication.. Anaphylactic hypersensitivity to previous measles vaccine, gelatin or neomycin and egg hypersensitivity Pregnancy

Control

Reporting Obligatory early reporting means better control of the outbreak. Isolation At community level is impractical . Children should be kept out of school for 4 days after appearance of rash. Respiratory isolation for hospital cases

Control

Contacts Live attenuated vaccine is effective if it given within 72 hrs of exposure. IG should be used within 6 days of exposure for susceptible contacts or other contacts with high risk of complications. For whom?????

Control

Contacts Risk of complication is high <1 year of age Pregnant women Immunocompromised If measles vaccine is contra indicated


4- Specific treatment (essential steps) Relieve common symptoms Provide nutritional support Promote breast feeding Giving vit A

Control

Specific treatment (essential steps) Vit A At the time of diagnosis Significantly reduces fatality Prevent blindness due to corneal ulceration and keratomalacia



Control 4- Specific treatment (essential steps) It is the recommended for children with measles in the following situations : Areas where measles CFR>1%. Areas of known vit A deficiency. In all cases of sever complicated measles.

Vit A 1st dose immediately on the Dx 2nd dose in the next day If the child has any eye signs indicating vitamin A deficiency, then a third dose must be given 2-4 weeks later Doses Infant<6 months 50.000 IU Infant 6-11 months 100.000 IU Infant 12 months 200.000 IU

Epidemic measures

Rapid (within 24 h) reporting of suspected cases. Comprehensive immunization program. In institutional outbreaks new admission should receive Ig. In many developing countries rapid immunization campaign is essential. If the vaccine supply is limited priority should be given to young children for whom the risk is greater.

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