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Meningococcal disease outbreak
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09/04/2010
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At present there is no meningococcal disease outbreak in Gauteng Province. Sporadic cases are occurring, but there has been no increase in the expected laboratory-confirmed cases of meningococcal disease to date this year as compared to the same period in previous years. Routinely we expect 10 to 20 laboratory-confirmed cases in Gauteng Province per month during the summer months, and this increases to 30 to 50 cases per month in the winter months.
Only three of the recent cases reported in the media were confirmed to have meningococcal disease in the laboratory. One other case was diagnosed based on clinical symptoms and signs and a number of other reported cases have been excluded or have had an alternative diagnosis confirmed on further testing.
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NICD Communique: Meningococcal disease
Prepared by the Outbreak Unit and Respiratory and Meningeal Pathogens Reference Unit of the National Institute for Communicable Diseases, South Africa
Compiled 10 March 2009
At present there is no meningococcal disease outbreak in Gauteng Province. Sporadic cases are occurring, but there has been no increase in the expected laboratory-confirmed cases of meningococcal disease to date this year as compared to the same period in previous years. Routinely we expect 10 to 20 laboratory-confirmed cases in Gauteng Province per month during the summer months, and this increases to 30 to 50 cases per month in the winter months.
Only three of the recent cases reported in the media were confirmed to have meningococcal disease in the laboratory. One other case was diagnosed based on clinical symptoms and signs and a number of other reported cases have been excluded or have had an alternative diagnosis confirmed on further testing.
There is always a need for a high index of suspicion for meningococcal disease because of non- specific early signs and symptoms, typically rapid progression and a need to manage patients as a medical emergency in order to reduce morbidity and mortality.
Etiological agent: Neisseria meningitides, or meningococcus, is a Gram-negative diplococcus.
Incidence: In 2008, 442 cases were recorded in South Africa involving all provinces. Gauteng, having 49% of the cases was most affected. Group W135 was predominant (43% of cases) followed by group A (25%). W135 was the most common serogroup in Gauteng.
Transmission: N. meningitidis colonizes mucosal surfaces of the nasopharynx and is transmitted through direct contact with large droplet respiratory secretions from patients or asymptomatic carriers. About 10% of the population may be asymptomatic carriers. The average incubation period for disease is 4 days, ranging between 2 and 10 days. Humans are the only host.
Risk Groups: Young children under 5 years of age and young adults are at highest risk of acquiring meningococcal disease. Military and police recruits, refugees, and young people who live in dormitories such as first year university and college students may also be considered as particular risk groups.
Clinical Features: Typically there is rapid progression of disease. Early signs and symptoms may include a petechial rash or ecchymoses which may appear first on the buttocks and/or conjuctiva, fever, intense headache, vomiting, joint and muscle pain, photophobia and neck stiffness. Lethargy or drowsiness is frequently reported. If coma is present, the prognosis is poor.
In children, irritability is a common presenting feature, and headache and neck stiffness may not be present. Projectile vomiting may occur. Seizures occur in 40% of children with meningitis, typically during the first few days.
Treatment: Meningococcal disease is potentially fatal and should always be viewed as a medical emergency. Admission to a hospital or health centre is necessary. Urgent empiric treatment with ceftriaxone should be given to all suspected cases. Ideally clinical specimens should be obtained prior to antibiotic therapy. However, lifesaving treatment should never be delayed in order to obtain specimens. Penicillin or ceftriaxone remains effective for treating patients with confirmed disease due to Neisseria meningitidis.
All cases of suspected meningococcal disease should be notified immediately by telephone to the Local/ District Department of Health so that follow-up of close contacts is undertaken quickly and to facilitate chemoprophylaxis. Clinical suspicion of meningococcal disease is sufficient for notification.
Post-exposure Prevention (PEP): Post-exposure prophylaxis with ciprofloxacin should be provided to household and close contacts of meningococcal disease cases.
Close contacts are defined as household contacts, people living in the same house and/ or sharing eating utensils with the index case, and persons exposed to nasopharyngeal secretions of the patient. Close contacts in an educational setting will usually include close friends who may share eating utensils or meet the other criteria for a close contact. Usually this does not mean the whole class, but only selected individuals within the class. It may be more difficult to define a close contact amongst younger children in preschools/ crèches but where possible post-exposure-prophylaxis should be limited to those who meet these criteria. Healthcare workers are generally not considered close contacts unless they have been directly exposed to the patient’s nasopharyngeal secretions.
Mass chemoprophylaxis is not recommended for control of meningococcal disease outbreaks and vaccination should only be considered in outbreak settings where appropriate and feasible.
Vaccine:
Meningococcal vaccine: Polysaccharide vaccines are available in South Africa for active immunisation against invasive disease caused by A, C, Y, or W135 serogroups (no effective vaccine exists to protect individuals from meningococcal meningitis caused by serogroup B). The vaccines available in South Africa are:
Imovax Meningo A+C®, Aventis Pasteur (will only protect against 2 serogroups, serogroup A and C)
Mencevax ACW135Y®, GlaxoSmithKline (will only protect against 4 serogroups, serogroups A, C, W135, and Y)
Menomune®, Aventis Pasteur (will only protect against 4 serogroups, serogroups A, C, W135, and Y)
Vaccination is recommended for:
pilgrims to Saudi Arabia, especially for Hajj and Umrah (quadrivalent vaccine is mandatory);
travellers to hyperendemic areas such as the meningitis belt in north Africa (Ethiopia in the east to Senegal in the west);
children and adults with functional or actual asplenia;
those with inherited terminal complement component deficiency;
those with laboratory or industrial exposure to N. meningitidis.
in a confirmed outbreak setting
The polysaccharide vaccines are not effective in children under 2 years of age.
Pneumococcal vaccine: Some confusion exists with regards to the pneumococcal vaccine. Please note that this vaccine will only protect against meningitis caused by Streptococcus pneumoniae. A new conjugated heptavalent vaccine contains capsular polysaccharide antigens of 7 S. pneumoniae serotypes.
It is safe and highly effective in preventing pneumococcal meningitis and bacteraemic pneumonia in young children under 2 years of age (including HIV-infected children); it is less effective in preventing otitis media.
Immunisation of infants with this vaccine has become routine in many countries, and is being introduced in the South African EPI (Expanded Programme on Immunization) on April 1, 2009.
It is registered for use in children aged 6 weeks–9 years; it is not recommended for use in older children or adults.
Pneumococcal vaccines available in South Africa include:
Purified polysaccharide antigen only (only effective in children >2 years)
Imovax Pneumo 23®, Aventis Pasteur (protects against 23 serotypes)
Pneumovax® 23, MSD
Polysaccharide-protein conjugated vaccine (effective in children <2 years of age):
Prevenar®, Wyeth, for serotypes 4, 9V, 14, 18C, 19F, 23F, 6B
National Institute of Communicable Diseases
Private Bag X4
2131 Sandringham
SOUTH AFRICA
E-mail: nicdmail@nicd.ac.za
Tel: 27-11-386 6000
Fax: 27-11-882 0596
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