[Naturally acquired tetanus antitoxin in the serum of children and adults in Mali].

Among 48 adults without a history of tetanus immunization, we found with the aid of indirect hemagglutination test 20 individuals with protective tetanus antibody titers, 23 with low levels of antitoxin (under 0,1 I.U./ml) and 5 devoid of tetanus antitoxin. In two blood samples of 99 unvaccinated children under 3 years of age (taken at 7 months intervall) 12,1% showed tetanus antitoxin in the first serum sample and 16,2% in the second sample. Protective antibody titers could be found only in 4 children in each of the first and second serum sample. The data suggest a silent oral immunization by tetanus bacilli thus boosting under unhygienic conditions the tetanus immunity with advancing age.