Validity of the recording of meningococcal disease according to various sources of information.

A study was made in Belgium in order to assess the completeness and specificity of the recording of meningococcal disease by routine sources of information. Ninety-three cases identified in a hospital survey were linked with those recorded in mortality statistics, in the notification of communicable diseases, and by the National Reference Laboratory for meningococci. Statistics based on mortality data appeared to be of low validity.

Longitudinal study of asymptomatic meningococcal carriage in two Belgian populations of schoolchildren.

In Brussels, a 15-month longitudinal survey was conducted in two primary schools, from March 1975 to May 1976, in order to analyse the dynamic of asymptomatic meningococcal carriage, during an epidemic mainly caused by serogroup B, serotype 2 Neisseria meningitidis. In the first school, which is situated in a suburban area with upper-middle socio-economic status of residents, a mean prevalence of carriers of 10 per cent, an acquisition rate of eight per 1000 months, and a mean duration of carriage of 12.4 months were observed among 158 schoolchildren aged six to 11 years old.

[Methods for analyzing the frequency, prevalence and the duration of asymptomatic carriage of Neisseria meningitidis. Longitudinal study of a school population in Belgium].

In Belgium, during an outbreak of meningococcal disease mainly due to serogroup B, serotype 2 meningococcus, a prospective study of asymptomatic carriage was undertaken in two primary schools. From march 1975 to may 1976, 361 schoolchildren aged 3 to 14 years were surveyed. The result of nasopharyngeal cultures were adjusted to compensate the lack of sensitivity and specificity of the identification techniques.

Pili of Neisseria meningitidis: an electron microscopic study on their occurrence, related to different strain characteristics.

The occurrence of pili has been assessed for 85 strains of Neisseria meningitidis belonging to different serogroups and serotypes, isolated from nasopharyngeal carriers and patients with acute disease. The evolution of piliation on multiple subcultivation has been followed for 16 strains. Almost all the strains were piliated, regardless of their origin, serogroup or serotype.