Etiology of suppurative bacterial meningitis

The results of the laboratory examination of 2034 patients with meningococcal infection and purulent meningitides, hospitalized during the period of June 1980 to October 1983, revealed that three main etiological agents were responsible for these diseases: meningococci, pneumococci and Haemophilus influenzae. The susceptibility of the patients to different etiological agents was found to depend on their age. Children aged up to 3 years constituted 75% of the patients with meningitis caused by H. influenzae; 50% of the patients with meningococcal infection were children aged up to 5 years; pneumococcal meningitis occurred more frequently in adults. Serogroup A meningococci were found to prevail in patients with meningococcal infection. Besides, in children serogroup C meningococci could be isolated in 24% of cases. Since 1983 the cases of the isolation of strains belonging to serogroup B increased in number. Among the pneumococci responsible for the disease serotypes 1, 19, 6 and in children serotype 12 occurred most frequently.     

The determination of antimeningococcal antibodies in the saliva of healthy people]

The determination of antibodies to the group-specific polysaccharide of group A meningococci (PS-A) in the saliva of 162 healthy persons at different seasons of the year revealed that antimeningococcal antibodies could be detected in all examines. The range of concentrations of antibodies to PS-A varied between 0.1 and 33.0 U/ml. The comparison of antibody content with the levels of morbidity in meningococcal infection and carriership made it possible to determine two threshold levels of antibody concentration: 9.0 U/ml and 18.0 U/ml.     

The evolution of meningococcal infection in Mongolia]

On the basis of the generalization and analysis of the results of bacteriological and immunological investigations the epidemic process of meningococcal infection (MI) in Mongolia was found to undergo definite changes during the last 20 years. Group A meningococci prevailing in the etiology of MI were replaced by strains belonging to group B affecting mainly young children (aged up to 3 years). MI morbidity rate caused by group B meningococci was found to be higher in Mongolia than in other countries of the world. These data substantiate the necessity of using more effective remedies for the control of this infection and, in particular, specific immunization with vaccines against group B meningococci; profound study of the properties of the circulating meningococcal strains is to be carried out.     

The effect of vaccination on local immunity indices; the determination of antimeningococcal antibodies in saliva]

Local immunity characteristics were studied in 130 young males; of these, 80 had been immunized with group A meningococcal vaccine. In nonstimulated saliva, collected prior to vaccination, then on days 7, 14 and 30 after vaccination, the levels of IgA antibodies to group A meningococcal group-specific polysaccharide (PS-A) were determined in the enzyme immunoassay, and secretory IgA and IgA, IgG, IgM were determined by Mancini's method. The study revealed that after the parenteral administration of group A meningococcal vaccine an increase in the concentrations of SIgA and IgA antibodies to PS-A occurred. The manifestation of changes in local immunity characteristics in response to meningococcal vaccine depended on the initial level of IgA antibodies to PS-A.