meningitis
Acute bacterial disease, characterized by sudden onset of fever, intense headache,nausea & vomiting, neck stiffness & petechial rashCase fatality rate exceed 50% but with early diagnosis it reduce to 5-15%
Diagnosis
recovery of meningiococci from the CSF & blood
Infectoius agent
Neisseria meningitides, group A,B,C,Y
Additional serogroup have been recognized as pathogen (eg. Groups W-135, X & Z)
Occurrence
meningococcal disease peaks in the late winter to early spring. It a disease of very small children, occurs commonly in children & young adults, in many countries in male more than female, & more commonly among newly aggregated adult under crowded living conditioning
Reservoir
humans
Mode of transmission
by direct contact, including respiratory droplet from nose & throat of infected people.Carrier prevalence of 25% or greater may exist without cases of meningitis
Incubation period
varies from 2-10 days, commonly 3-4 days
Period of communicability
Until meningiococci are no longer present in discharge from the nose & mouth. Meningiococci usually disappear from the nasophyranx within 24 hr after antimicrobial stopped
Susceptibility & resistance
Susce. To the clinical disease is low& decrease with age , a high ratio of carriers to cases. Those who are deficient in certain complement component are specially prone to recurrent disease. Splenictomized persons are susceptible to bacteremic illness
Group specific immunity of unknown duration follows even subclinical infections
Methods of control
A- Preventive measures
1- educate the public on the need to reduce direct contact & exposure to droplet infection & reduce overcrowding in living & work place
2- vaccines containing groups A , C, Y & W135 meningococcal polysaccharide vaccine
It should be given to certain high risk groups over 2 years old who are especially susceptible to serious meningococcal infections, including
Asplenic patients, persons with
terminal complement deficiencies & laboratory personals who are expose routinely to N Sero group A vaccine is effective in younger children, for those 3 m- 2 years old, doses are given 3 months apart in stead of the single dose given to those over 2 years of age
B- control of patients, contact & the immediate environment
1- report to local health authority: obligatory case report
2- isolation: respiratory isolation for 24 hr after start of chemotherapy
3- concurrent disinfection: of discharge from the nose & throat & articles solids therewith
4- quarantine: none
5- protection of contacts
close surveillance of hose hold, day care & other intimate contact for early signs of illnesses especially fever, to initiate appropriate therapy without delay (close friends at school but not the whole class)
Younger children in day care centre are ,&, even if not close friend, all should be given prophylaxis after an index case is identified
The prophylactic antibiotic agents of choice is refampicin twice
daily for two days
Adults 600 mg/dose
Children over 1 month old 10 mg/kg
Children less than 1 month old 5mg/kg
6-investigation of contacts & source of infection, throat or nasopharyngeal culture are of no value in deciding who should receive prophylaxis
The prophylactic antibiotic
agents of choice is refampicin twice daily for two days Adults 600 mg/dose
Children over 1 month old 10 mg/kg
Children less than 1 month old 5mg/kg
6-investigation of contacts & source of infection: throat or nasopharyngeal culture are of no value in deciding who should receive prophylaxis
7- specific treatment, penicillin given parentally in adequate doses is the drug of choice, ampicillin & chloramphenicol are also effective
C- Epedmic measures
1- when an outbreak occurs: careful surveillance, early diagnosis & immediate treatment of suspected cases
2- separate individuals, & ventilate living & sleeping room of all people who are expose to infections because of crowding living conditions
3- mass chemoprophylaxis is usually not effective in controlling outbreaks but if outbreaks involving small population ( eg. A single school), administration of chemoprophylaxis to all persons within the population may be considered, it should be given to all members of the community at the same time
4- the use of the vaccine in all age group should be strongly considered san outbreak occurs in a large institutional or community setting in which the case are due to group A, C, W125 or Y.
Meningococcal vaccine is very effective in epidemics due to A & C groups.