FAQ
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| Meningococcal Infection |
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What is Meningococcal Infections?
Meningococcal infection is caused by the bacteria Neisseria meningitidis. Meningitis and meningococcemia are the most common manifestations of the disease, although it has been known to cause septic arthritis, pneumonia, brain inflammation and other syndromes.
What is "Meningococcal meningitis"?
Meningococcal meningitis is an infection of the meninges by the bacteria. It is the most common presentation of meningococcal infection. Symptoms include high fever, severe headache, stiff neck followed by drowsiness, vomiting, fear of bright lights, or a rash. The disease can cause brain damage or even death.
How about "Meningococcemia"?
It is one kind of manifestations of meningococcal infection when the bacteria invade the blood stream. It is characterized by sudden onset of fever, intense headache, purpura, shock and even death in severe cases. Vomiting, photophobia and meningeal symptoms occur less frequently.
What are the possible complications of the disease?
Meningococal meningitis may result in brain damage, leading to intellectual impairment, mental retardation, hearing loss and electrolytes problems. For invasive meningococcal infections, it can be complicated by arthritis, myocarditis, endophthalmitis or pneumonia.
How is the disease diagnosed?
The diagnosis of invasive meningococcal diseases is confirmed by isolating N. meningitidis from a usually sterile site such as blood and cerebrospinal fluid.
How does the disease managed?
Meningococcal infection is a serious illness. Suspects should be treated immediately
with suitable antibiotics. Close contacts would need to be placed under surveillance
for early signs of disease and may be given preventive medications.
How is meningococcal meningitis spread?
The disease is transmitted by direct contact through droplets of respiratory secretions from infected persons.
What is the incubation period?
The incubation period varies from 2 to 10 days, commonly 3 to 4 days.
Who is susceptible?
The risk of infection is higher among close contacts of patients with MI. Close
contacts include (1) household members, (2) day care centre contacts, (3) persons
directly exposed to the patient's oral secretions, and (4) those who frequently
sleep or eat in the same dwellings as the patient. Certain patients with defective
immune systems are also at higher risk. Other risk factors include antecedent
viral infection, overcrowding, chronic underlying illness, and active and passive
smoking.
Is it common in Hong Kong?
Meningococcal infection is a statutorily notifiable disease in Hong Kong. During 1990-2004, the number of notifications ranged from 2-14 per year, and a total of 85 cases were reported during this period. The annual incidence rate was between 0.03-0.21 per 100,000 population.
What is the risk of acquiring the disease for travellers ?
In general, the risk of acquiring meningococcal infection while travelling is
low. However, in sub-Saharan Africa extending from Mali to Ethiopia, particularly
in the savanna during the dry season (December to May), disease occurrence is
higher, and there is additional risk for those visitors who travel "rough"
such as backpackers, and those who need to live or work with local people.
Is there a vaccine for the disease?
Presently two preparations of meningococcal vaccines are registered in Hong Kong - the bivalent (serogroups A & C) and the quadrivalent (serogroups A, C, Y & W135). Locally, the incidence of meningococcal infections is low and about half of the meningococcal infections were caused by Neisseria meningitidis serogroup B. The quadrivalent meningococcal vaccine does not confer protection against meningococcal infections caused by serogroup B, its duration of protection is short and it is relatively ineffective in children aged under 2. There is insufficient justification to include the quadrivalent meningococcal vaccine in the universal immunization programme in Hong Kong in light of current evidence.
How can travellers prevent it?
As the disease is transmitted by direct contact and droplets of respiratory secretions, travellers are advised to:
1. Observe personal hygiene especially the practice of hand washing
2. Keep hands clean and wash hands properly
3. Wash hands when they are dirtied by respiratory secretions, e.g. after sneezing
4. Cover nose and mouth while sneezing or coughing and dispose of nasal and mouth
discharge properly.
To minimize the risk of meningococcal infection, vaccination may be considered
for those staying in the sub-Saharan Africa during the dry season. Travellers
visiting Saudi Arabia during the Hajj annual pilgrimage should bring along certificate
of vaccination issued not more than 3 years and not less than 10 days before arrival
in Saudi Arabia.
Vaccination is not recommended for travellers making short-term business or holiday trips in areas of heightened meningococcal activity if they will have little contact with or exposure to local population in crowded conditions.
Travellers returning from high risk areas should seek medical advice if they become ill after returning from their trips. They should discuss their recent history with the doctor.
Prepared by
Vaccine Preventable Disease Office
Surveillance and Epidemiology Branch, CHP
February 2005
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