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Delhi safe, no meningitis threat

As far as the present outbreak is concerned the message is very clear, Delhi is safe for travellers, writes Dr KK Aggarwal.

india Updated: Mar 14, 2006 18:57 IST

Delhi is again in the grip of brain fever called meningitis. The word meningitis is sufficient to create hysteria amongst public. It also causes a concern for international travellers whether they should visit Delhi or not. As far as the present outbreak is concerned the message is very clear, Delhi is safe for travellers. It is only a focal outbreak with case rate less than 2.5 per 100,000 population and does not warrant public vaccination, travel restrictions or antibiotic prophylaxis. However, we all need to know some facts about the disease so that necessary knowledge can be acquired and precautions taken.

Delhi Medical Association reported the first case of meningococcal relapse on December 7. Ever since, over 200 cases have been reported in various parts of Delhi.

Meningococcal disease is endemic in Delhi and sporadic cases of meningococcal meningitis have been occurring in Delhi in previous years. Outbreaks of the disease occur in cycles. Outbreaks of meningococcal meningitis in and around Delhi, India have been documented during 1966 and 1985 and 2005. (20 years cycle) Next cycle is expected to be in 2025.

Lessons learnt from outbreak in March 1966:
616 cases of meningitis were reported in 5 major hospitals in Delhi with case-fatality rate of 20.9 per cent. The highest proportion of cases and deaths occurred in age group less than 1 year followed by that in 1-4 years. The male to female ratio was almost 3:1. The proportion of laboratory confirmed cases increased from 4.8 per cent in January to 10.6 per cent in February to reach a peak of 44.9 per cent in May 1966. Outbreak was due to meningococcus serogroup A. Overall in 18.8 per cent of the cases, meningococci were proved to be the causative agent. Two peaks were noticed - one in May and the other in December 1966.

Lessons learnt from outbreak in 1985-86:
After a gap of about 20 years, Delhi and adjoining areas experienced another outbreak of meningococcal meningitis. The outbreak in 1985 was bigger in magnitude, both in terms of cases and the geographical area affected. The causative agent was again meningococcus serogroup A. During the year 1985, a total number of 6133 pyogenic meningitis cases with 799 deaths were recorded, with an overall case-fatality of 13 per cent as compared to 1731 cases and 569 deaths in the year 1984. The male to female ratio of cases was 3:1. Isolated cases of meningococcal meningitis during 1985 were also reported from several other parts of India namely Haryana, Uttar Pradesh, Rajasthan, Sikkim, Gujarat, Jammu & Kashmir, West Bengal, Chandigarh, Kerala and Orissa. In 1985 Bhutan was also hit by meningitis and 247 cases with 41 deaths were reported between September 1985 and March 1986. During 1982-1984 1475 cases occurred in Kathmandu valley, Nepal with highest mortality and morbidity in children less than one year of age.

Lessons learnt from outbreak in May 2005:
Starting March 29 Delhi had another outbreak. 441 cases of meningococcal disease were reported. With 60 deaths (CFR=13.6 per cent) the outbreak ended by July 1, 2005. The cumulative number of cases during the outbreak period was 441 cases. Majority of cases and all deaths have occurred in young adult population. The National Institute of Communicable Diseases (NICD) has demonstrated the presence of Neisseria meningitidis serogroup A in cerebrospinal fluid. Most cases have been reported from Old Delhi. The attack rate was less than five per 100,000.

The current outbreak:
On December 7, 2005 the first case of Meningococcemia was reported and since then over 200 cases has occurred. The attack rate is less than 2.5 per 100,000.
The most important step in preventing the spread of the disease is chemoprophylaxis of close contacts after a case is identified.

Case Definition: Meningitis
Meningitis
1. Suspected case of acute meningitis
Sudden onset of fever (>38.5ºC rectal or 38.0ºC axillary), with stiff neck
(in patients under one year of age, a suspected case of meningitis occurs when fever is accompanied by a bulging fontanelle)

2. Probable case of bacterial meningitis
Suspected case of acute meningitis as defined above, with turbid CSF

3. Probable case of meningococcal meningitis
Suspected case of either acute or bacterial meningitis as defined above, with Gram stain showing Gram-negative diplococcus, or ongoing epidemic, or petechial or purpural rash.

4. Confirmed case
1. Suspected or probable case as defined above, with either positive CSF antigen detection for N. meningitidis, or Positive culture of CSF or blood with identification of N. meningitidis

Standard case definition of Meningococcemia
Meningococcemia

Probable: Sudden onset of fever (>38.5ºC rectal or 38.0ºC axillary) with or without shock, and one of the following
i. Petechial or purpural rash
ii. Gram stain showing Gram-negative diplococcus

Confirmed: Probable case, and
Demonstration of N. meningitidis or antigen in blood and/or CSF

Normally, seasonal occurrence is highest during the winter with the majority of cases occurring in January and February. But 2005 epidemic started in May. Normally it is more common in young age groups but 2005 epidemic was in adults. It is more common in the central parts of the town.

The bacteria that cause meningococcal disease are spread through close, direct contact with an infected person that leads to exchange of saliva or respiratory and throat secretions (e.g., kissing or shared eating utensils). Of those exposed to the bacteria, less than 1 per cent develop illness. The bacteria are not spread by casual contact or by simply breathing the air where a person with meningococcal disease has been.

The decision to start mass prophylaxis depends on the primary attack rate. A primary case of meningococcal disease is one that occurs in the absence of previous known close contact with another patient. A secondary case of meningococcal disease is one that occurs among close contacts of a primary patient more than 24 hours after onset of illness in the primary patient. Co-primary cases are two or more cases that occur among a group of close contacts with onset of illness separated by less than 24 hours.

Close contacts of a patient who has meningococcal disease include (i) house-hold members; (ii) child-care centre contacts and (iii) persons directly exposed to the patient's oral secretions (e.g., by kissing, mouth-to-mouth resuscitation, endotracheal intubation, or endotracheal tube management).

Community-based outbreak is defined as the occurrence of three or more confirmed or probable cases of meningococcal disease in less than 3 months among persons residing in the same area who are not close contacts of each other and who do not share a common affiliation, with a primary disease attack rate of more than 10 primary cases/100,000 persons.

For a primary attack rate to be calculated, all confirmed cases of the same serogroup should be added; secondary cases should be excluded and each set of co-primary cases counted as one case. Attack rate per 100,000 = [(number of primary confirmed or probable cases during a 3-month period) / (number of population at risk)] × 100,000. 2005 outbreak the attack rate was less than 5/100,000 population. 2006 outbreak the attck rate is less than 2.5/100,000 population.

Prevention is the most important. One should wash hands properly after coming in contact with patient. One should cover the nose, mouth while coughing and sneezing. Everyone should keep a watch for the symptoms of disease.

In the event of noticing any symptoms of disease one should immediately contact the doctor. One should avoid going to crowded places. One should not share food, drinks, smoking, clothing and bedding with a person having illness. One should not panic, as the disease is curable. Early diagnosis and management is the key in prevention.

Chemoprophylaxis should be given to close contacts in household and health care workers. Vaccination of high-risk group is important. Health education should be done to allay fear and improve knowledge of signs and symptoms to seek early treatment. Respiratory isolation of all patients should be done for 72 hours.

Please report
All probable or confirmed cases of Meningococcal meningitis or Meningococcemia are required to be reported to the (i) DHA (MCD), Tel: 23936101; Fax: 23942056, 23832314, (ii) Director (EMR), Tel: 23017302; Fax: 23017457, and (iii) Director, NICD, Tel: 23971272, 23971060, 23912836; Fax: 23922677

The writer is a senior Physician, Head Department of Cardiology and Deputy Dean Board of Medical Education-Moolchand Hospital, President-Heart Care Foundation of India, President Delhi Medical Association and Member-Delhi Medical Council.

First Published: Mar 14, 2006 18:57 IST