Carriage rate of Neisseria meningitidis and some observations on the persistence of immunity in school children in parts of northern Nigeria
Carriage rate of Neisseria meningitidis and some observations on the persistence of immunity in school children in parts of northern Nigeria
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Date
1983-09
Authors
Enabulele, Onaiwu Idahosa
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Abstract
Asymptomatic carriage of Neisseria meningitidis was
studied in a total of 502 healthy school childrer in Zaria
214 in Shika and 332 in parts of Kano State, all in Nigeria
between the months of August and December, 1982.
The prevalence of N. meningitidis averaged 2I4.68% in Zaria
12.60% in Shika and 7.88% in Kano. The prevalence of
N. meningitidis averaged 17.67% in children aged 5 - 7 years
and increased to 36.67% in children aged 14 - 16 years old
among those investigated in Zaria. In Shika, it averaged
6.91% in children aged 5 - 7 years and increased to 16.67% in
those aged 14 - 16 years while in Kano, it average 4. 33%
in the former set of children and increased to 14.28% in
latter. There was no sex influence on the rate of
meningococcal carriage in the groups studied.
Analysis of the duration of immunity in school children
vaccinated against groups A, meningococci was carried out
three years after the children had received a bivalent
(A + C) meningococcal polysaccharide vaccine. Sera were
obtained from 69 of such immunized children in parts of Kano
State. Additional 53 sera specimens were collected from
non-vaccinated school children from the same area and used
as controls.
The duration of immunity to group A meningococci was
determined by measuring meningococcal antibody levels in
serum samples using the complement-dependent bactericidal
antibody assay technique. It was observed that three
years after vaccination, the group A meningococcal
antibody level was much higher in the immunized children
than in the control group of similar age range.
Furthermore, it was observed that the rate of
meningococcal carriage was much lower in the immunized
children than in the non-immunized group. Meningococcal
carriage amongst the groups investigated, showed that
only group C meningococci was present in very low number
amongst the vaccinated school children (5 carriers among
69 children), and group A meningococci was completely
absent in these children. In general, carriers for
meningococci groups A, D and X were absert in Kano and
Shika whereas these groups were prominently present
in Zaria. In addition, carriage rate for group C
was identically low in Kano and Shika and significantly
higher in Zaria.
The persistence of elevated level of bactericidal
antibodies in both immunized and non-immunized
children was found to be markedly age dependent.
Description
A project report submitted to the school of
postgraduate studies, Ahmadu Bello University Zaria,
Nigeria, in partial fulfillment of the requirements
for the degree of Master of Science in Microbiology.
Keywords
Carriage,, rate,, Neisseria meningitidis,, observations,, persistence,, immunity,, school children,, parts,, northern Nigeria