Understanding cerebrospinal meningitis
By Chukwuma Muanya, Assistant Editor
According to a Fact Sheet on Meningitis by the World Health Organisation (WHO), meningococcal meningitis is a bacterial form of meningitis, a serious infection of the thin lining that surrounds the brain and spinal cord.
The extended meningitis belt of sub-Saharan Africa, stretching from Senegal in the west to Ethiopia in the east (26 countries), has the highest rates of the disease. Before 2010 and the mass preventive immunization campaigns, Group A meningococcus accounted for an estimated 80–85 per cent of all cases in the meningitis belt, with epidemics occurring at intervals of seven–14 years. Since then, the proportion of the A serogroup has declined dramatically.
During the 2014 epidemic season, 19 African countries implementing enhanced surveillance reported 11 908 suspected cases including 1146 deaths, the lowest numbers since the implementation of enhanced surveillance through a functional network (2004).
Several vaccines are available to control the disease: a meningococcal A conjugate vaccine, C conjugate vaccines, tetravalent A, C, Y and W conjugate vaccines and meningococcal polysaccharide vaccines.
As of June 2015, over 220 million persons aged 1 to 29 years have received meningococcal A conjugate vaccine in 15 countries of the African belt.
Meningococcal meningitis is a bacterial form of meningitis, a serious infection of the meninges that affects the brain membrane. It can cause severe brain damage and is fatal in 50 per cent of cases if untreated.
Several different bacteria can cause meningitis. Neisseria meningitidis is the one with the potential to cause large epidemics. There are 12 serogroups of N. meningitidis that have been identified, six of which (A, B, C, W, X and Y) can cause epidemics. Geographic distribution and epidemic potential differ according to serogroup.
The bacteria are transmitted from person-to-person through droplets of respiratory or throat secretions from carriers. Close and prolonged contact – such as kissing, sneezing or coughing on someone, or living in close quarters (such as a dormitory, sharing eating or drinking utensils) with an infected person (a carrier) – facilitates the spread of the disease. The average incubation period is four days, but can range between two and 10 days.
Neisseria meningitidis only infects humans; there is no animal reservoir. The bacteria can be carried in the throat and sometimes, for reasons not fully understood, can overwhelm the body’s defenses allowing infection to spread through the bloodstream to the brain. It is believed that 10 per cent to 20 per cent of the population carries Neisseria meningitidis in their throat at any given time. However, the carriage rate may be higher in epidemic situations.
Commissioner for Health, Lagos State, Dr. Jide Idris, explained that CSM is a dangerous and a life threatening disease that affects the thin layers of the tissue around the brain and spinal cord of an infected human person and is caused by bacteria.
He added that Cerebrospinal meningitis is an epidemic prone disease that spreads from person to person through contact with discharges or droplets from nose and throat of an infected person. It can also be transmitted through kissing, sneezing and coughing especially amongst people living in close quarters, hotels, refugee camp, barracks, public transportation and areas with poor ventilation or overcrowded places.
The most common symptoms are a stiff neck, high fever, sensitivity to light, confusion, headaches and vomiting. Even when the disease is diagnosed early and adequate treatment is started, five per cent to 10 per cent of patients die, typically within 24 to 48 hours after the onset of symptoms. Bacterial meningitis may result in brain damage, hearing loss or a learning disability in 10 per cent to 20 per cent of survivors. A less common but even more severe (often fatal) form of meningococcal disease is meningococcal septicaemia, which is characterized by a haemorrhagic rash and rapid circulatory collapse.
Idris explained that the disease usually presents with high body temperature, pain and stiffness of the neck, headache, vomiting, fear of light, restlessness and confusion stressed that death may occur if not promptly and properly managed.
Initial diagnosis of meningococcal meningitis can be made by clinical examination followed by a lumbar puncture showing a purulent spinal fluid. The bacteria can sometimes be seen in microscopic examinations of the spinal fluid. The diagnosis is supported or confirmed by growing the bacteria from specimens of spinal fluid or blood, by agglutination tests or by polymerase chain reaction (PCR). The identification of the serogroups and susceptibility testing to antibiotics are important to define control measures.
Meningococcal disease is potentially fatal and should always be viewed as a medical emergency. Admission to a hospital or health centre is necessary, although isolation of the patient is not necessary. Appropriate antibiotic treatment must be started as soon as possible, ideally after the lumbar puncture has been carried out if such a puncture can be performed immediately. If treatment is started prior to the lumbar puncture it may be difficult to grow the bacteria from the spinal fluid and confirm the diagnosis.
A range of antibiotics can treat the infection, including penicillin, ampicillin, chloramphenicol and ceftriaxone. Under epidemic conditions in Africa in areas with limited health infrastructure and resources, ceftriaxone is the drug of choice.
There are three types of vaccines available.
Polysaccharide vaccines have been available to prevent the disease for over 30 years. Meningococcal polysaccharide vaccines are available in either bivalent (groups A and C), trivalent (groups A, C and W), or tetravalent (groups A, C, Y and W) forms to control the disease.
For group B, polysaccharide vaccines cannot be developed, due to antigenic mimicry with polysaccharide in human neurologic tissues. The first vaccine against NmB, made from a combination of four protein components, was released in 2014.
Since 1999, meningococcal conjugate vaccines against group C have been available and widely used. Tetravalent A, C, Y and W conjugate vaccines have been licensed since 2005 for use in children and adults in Canada, the United States of America, and Europe.
The extended meningitis belt of sub-Saharan Africa, stretching from Senegal in the west to Ethiopia in the east (26 countries), has the highest rates of the disease. The 26 countries include: Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Côte d’Ivoire, Democratic Republic of Congo, Eritrea, Ethiopia, The Gambia, Ghana, Guinea, Guinea Bissau, Kenya, Mali, Mauritania, Niger, Nigeria, Rwanda, Senegal, South Sudan, Sudan, Tanzania, Togo and Uganda. The risk of meningococcal meningitis epidemics differs within and among these 26 countries.
In December 2010, a new meningococcal A conjugate vaccine was introduced nationwide in Burkina Faso, and in selected regions of Mali and Niger (the remaining regions were covered in 2011), targeting persons one to 29 years of age. As of June 2015, 220 million persons have been vaccinated with this vaccine in 16 countries (Benin, Burkina Faso, Cameroon, Chad, Côte d’Ivoire, Ethiopia, The Gambia, Ghana, Guinea, Mali, Mauritania, Niger, Nigeria, Senegal, Sudan, and Togo).
The Commissioner therefore emphasized the need for the observance of high standards of personal and environmental hygiene as a preventive measure against the disease. He also noted that such measures should include washing of hands with soap and water frequently; avoiding direct contact with the discharges from an infected person and covering of the mouth and nose when coughing and sneezing.
“It is strongly advised for people to avoid overcrowding in living quarters, provide cross ventilation in sleeping and work-rooms and other places where many people come together and get vaccinated with CSM vaccine when you are travelling to areas where Meningitis outbreaks have been reported”, he added.
Idris noted that health workers in the State, especially health workers in the hospitals, the State Epidemiology team and the Disease Surveillance and Notification Officers (DSNOs) in all the 57 Local Governments and Local Council Development Areas have been placed on high alert and therefore the disease surveillance and monitoring activities have since been intensified.
“Health workers are also advised to avoid close contact with suspected and probable cases of CSM based on the case definition distributed, ensure proper disposal of respiratory and throats secretions of cases, report suspected or probable cases, observe universal safety precautionary measures and make use of personal protective equipment when in contact with such cases as highlighted in the Fact-Sheets earlier forwarded to them,” he noted.
While urging residents to take responsibility for their health and report persons with the above symptoms to the nearest public health facility or the Ministry of Health, the Commissioner stated that the State Government had put in place all the above measures towards avoidance and prevention of outbreak of CSM in Lagos State.
The Commissioner concluded his brief by advising the general public to remain calm and report suspected cases to the nearest public health facility or contact Disease Surveillance Officers of the Ministry of Heath on the following GSM numbers 08037170614, 09087106072, 08023169485, 08052817243, 08026441681.
Source: The Guardian