Blood or cerebrospinal fluid culture is the main diagnostic method, but blood PCR may be useful if antibiotics are given without prior access to blood culture. Three to five millilitres of blood should be taken in an EDTA anticoagulant tube (usually with a purple top).
The overall rate of secondary cases in untreated adults is around 1 per 300. Adults and children in close contact with primary cases of invasive meningococcal infection are recommended to receive antibiotic prophylaxis, preferably within 24 hours of the initial diagnosis, but prophylaxis is recommended up to 14 days after diagnosis of illness.
A contact is anyone who has had unprotected contact with upper respiratory tract or respiratory droplets from the case during the seven days before onset of illness to 24 hours after onset of effective treatment.42 Contacts at particular risk include:
Prophylaxis is not routinely recommended for health care personnel unless there has been intimate contact with oral secretions (eg, as a result of performing mouth-to-mouth resuscitation or suctioning of the case before antibiotic therapy has started).
The recommended antibiotics are rifampicin, ceftriaxone or ciprofloxacin.
The recommended dose of rifampicin is 10 mg/kg (maximum dose 600 mg) every 12 hours for two days. For infants aged under 4 weeks, the recommended dose is 5 mg/kg every 12 hours for two days.
A single dose of intramuscular ceftriaxone (125 mg for children aged under 12 years and 250 mg for older children and adults) has been found to have an efﬁcacy equal to that of rifampicin in eradicating the meningococcal group A carrier state. Ceftriaxone is the drug of choice in a pregnant woman because rifampicin is not recommended later in pregnancy. Ceftriaxone may be reconstituted with lignocaine (according to the manufacturer’s instructions) to reduce the pain of injection. A New Zealand study demonstrated that ceftriaxone and rifampicin were equivalent in terms of eliminating nasopharyngeal carriage of N. meningitidis group B.43
Ciproﬂoxacin given as a single oral dose of 500 mg or 750 mg is also effective at eradicating carriage. This is the preferred prophylaxis for women on the oral contraceptive pill and for prophylaxis of large groups.42 Ciproﬂoxacin is not generally recommended for pregnant and lactating women or for children aged under 18 years.44 Consult the manufacturer’s data sheet for appropriate use and dosage of ciprofloxacin in children.
Close contacts of cases of meningococcal disease may be offered the appropriate meningococcal conjugate vaccine (see section 12.5). See below for the use of the vaccines for the control of outbreaks.
When there is an outbreak of meningococcal disease of a specific vaccine group, the medical ofﬁcer of health and Ministry of Health assess the epidemiology of the cases as follows.
When there is an organisation or community outbreak, an immunisation programme may be recommended and funded for a deﬁned population.