Measles
DR HADEEL FADHIL
An acute highly communicable viral disease with prodromal fever, conjunctivitis, coryza, cough & small spots with white or bluish white centers on erythematous base on the buccal mucosa (Koplike spots).
A characteristic red rash appears
on the third to seven day, the
rash begin on the face then become generalized last 4-7 days, leucopenia
is common.
The disease is more severe in infant & adult than in children.
The case fatality rate in developing countries are estimated to be 3-5% & may reach 10-30% in some localities.
Diagnosis: usually made on clinical & epidemiological ground & confirmation by detection of measles specific IgM Abs which appear 3-4 day after rash, detect of viral antigen in nasopharyngeal mucosal swab.
Children with clinical or subclinical vit A deficiency are at particular high risk to severe disease.
The children who are border line nourished, measles often precipitate acute kwashiorkor & exacerbate vit A deficiency, that lead to blindness.
Complications
*otitis media
*pneumonia
*larangeotracheobronchitis (croup)
*diarrhea
*encephalitis
Infectious agent: measles virus, paramyxoviridae
Occurrence:
Before the immunization, measles was common in childhood, more than 90% of people had been infected by age of 20 years old.
Measles was endemic in many countries & appear as epidemic every second or third year .
In smaller communities and areas Outbreak tend to be more wildly spaced & more severe with longer interval between outbreaks.
In temperate climate, measles occur in late winter & early spring .
In tropical climate , measles occur in dry season.
Reservoir: human
Mode of transmission
() Air borne by droplet spread
() Direct contact with nasal or throat secretions of infected person
() By articles freshly soiled with nose &
throat secretion (less common)
Measles is one of the most highly communicable diseases.
() incubation period: about 10 days, but may be 7-18 days from the exposure to onset of fever, usually 14 days until rash appears.
Rarely as long as 19 -21 days.
() period of communicability:
Usually about 4 days before rash onset to 4 days after the rash
()susceptibility & resistance:
- all persons who not had
the disease
- all persons not succefully
immunized
Acquired immunity after illness is permanent
Infants borne to mothers who had the disease are protected for 1st 6-9 months or more .
Immunizations at 12-15 months induces immunity in 94-98%
Methods of control
A- preventive measures:
1- public education by health department to encourage measles immunization for all susceptible infant, children , adolescent & young adult.
Those for whom vaccine is contraindicated & un immunized persons identified more than 72 hr after exposure to measles may be partially or completely protected by IG given within 6 days after exposure.
2- immunization:
Live attenuated measles vaccine. in combined with other live vaccine ( mumps , rubella ) should induced active immunity in 94%-98% of susceptible individual, possibly for life , by producing mild or in apparent , no communicable infection .
A second dose of measles vaccine may increase immunity level to 99% .
Contraindications to live virus vaccines:
- immunodeficiency diseases
- severe acute illness with or without fever
- anaphylactic hypersensitivity to previous dose of measles vaccine
- pregnancy
- vaccine should be given at least 14 days before immunoglobulin or blood transfusion.
IG or blood product can interfere with response to measles vaccine
Complications of measles immunization:
- 5-15% may develop malaise & fever to 39.4 cent within 5-12 days post immunization & last 1-2 days.
- rash coryza mild cough & kop like spots may occur
-febrile seizure occur infrequently
- encephalitis & encephalopathy (less than one case per million doses)
B- control of patient , contact & immediate environment:
1- obligatory case report to local health authority
2- isolation: children with measles should be kept out of school for 4 days after rash. In hospital , respiratory isolation.
3- concurrent disinfection: none
4- quarantine : of institutions , wards can sometimes be of value. Strict segregation of infants if measles occur in institution .
5- immunization of contacts :
live virus vaccine is given within 72 hours of exposure.
IG may be use within 6 days of exposure for susceptible household or other contact ( particularly contact under 1 year of age, pregnant or immunocompromised persons or for whom measles vaccine is contraindicated
Live measles vaccine should be given 5-6 months later to those the vaccine is not contraindicated .
6- investigations of contacts & source of infection:
Search for & immunizations of exposed susceptible contacts should be carried out to limit spread of disease. Carriers are unknown.
7- specific treatment : none
C- epidemic measures:
1- prompt reporting within 24 hr of suspected cases & comprehensive immunization programs for all susceptible are needed to limit spread .
In day care, school & college outbreaks, all persons take 2 doses of live virus vaccine at least 1 month apart should be immunized unless they have diagnose measles or laboratory evidence of immunity.
2- in institutional outbreaks, new admission should receive vaccine or immunoglobulin.
3- in many less developed countries, measles has a relatively high case fatality rate. If vaccine is available, prompt use at the beginning of an epidemic is essential to limit spread, if vaccine supply is limited, priority should be given to young children for whom the risk is greatest