Immunological surveys of diphtheric antitoxic antibodies in some African and Asian countries.

Immunological surveys of diphtheric antitoxic antibodies confirmed the existence of a high circulation of Corynebacterium diphtheriae in some African and Asian countries. The high immunity level in early childhood confirms the well known fact that other forms of diphtheria, in particular the cutaneous forms, participate in the formation of antitoxic antibodies. Immunological surveys can determine relatively exactly the extent of risk of infection in the separate age groups and thus delimit the range of the planned vaccination campaigns. Exact determination of the age groups eligible for vaccination makes it possible efficaciously to employ the means allotted for the health services. In some cases, it is possible to dispense with vaccination altogether. However, it should be borne in mind that a change in the socio-economic conditions and increasing urbanization of these countries may induce a radical change in the situation. Children not protected from the cutaneous forms thanks to a better hygienic and social standard, might fall ill with diphtheria of the throat in the future. It is therefore advisable to continue the follow-up of the immune state of the child population at several years time intervals and, in case of necessity, timely to intervene by vaccinating the endangered groups.

PIP: This article summarizes diphtheria antitoxic antibody surveys in 6740 sera from 11 African and Asian countries, and reviews the literature on the immunology of diphtheria. Classic diphtheria of the throat is primarily a temperate zone phenomenon. In subtropical and torrid zones, other forms, mainly cutaneous diphtheria, still prevail. Antitoxic antibodies are present in the majority of preschool children in the tropics, while complete immunization in the subtropics takes 10-15 years. In this survey, in collaboration with the WHO Reference Serum Bank, the authors assayed diphtheria antitoxic antibodies in 6740 sera from 1967-1973 by titration on monkey kidney tissue cultures, by the pH metabolic inhibition test. The countries surveyed were Nigeria, Niger, Kenya, Togo, Burma, Algeria, Tunisia, Afghanistan, Mongolia, Yugoslavia. Most countries had adequate natural immunity at an early age. Exceptions were parts of Tunisia, and most of Afghanistan where morbidity was high. Yugoslavia used to have the highest morbidity in Europe from diphtheria, but 90% of children are now immunized. It is important to note that the percentage of immunized children is highest where hygiene is poor, in the tropics, and among rural rather than urban dwellers, and in boys rather than girls. Prolonged breast feeding appears to confer immunity in children. Therefore, as hygiene improves with modernization and urbanization, cutaneous diphtheria disappears, and populations will need to be protected by vaccination.

Immunological surveys of antibodies against B. pertussis and B. parapertussis in some African and Asian countries.

Immunological surveys in African and Asian countries showed a different degree of herd immunity in the respective countries and the circulation of various types of B. pertussis. Antibodies against B. parapertussis, the second aertiological agent of whooping cough, were found in all countries in all age groups. Before planning any vaccination program, attention should be paid to the vaccine concerning the content of all types of B. pertussis, as was shown in the results of the testing of different vaccines used in Mongolia and Algeria. It is also possible to estimate the age limit for vaccination and thus economic use of the vaccine. The contemporary state of reporting whooping cough cases is very unsatisfactory.

Immunity status of Czech population with regard to poliomyelitis in 1970--1975.

The results of examination of antibodies against all three types ofthe poliomyelitis virus from the period of systematically performed multipurpose immunological survey in the Czech Socialistic Republic (1970--1975) are presented and evaluated. The analysis of these results indicates that the status of immunity in the Czech population, systematically vaccinated against poliomyelitis, is good, as all requirements of collective protection against this disease have been met. At the same time, the results demonstrated that immunological surveys are at present the most suitable method of verifying the immunity of the vaccinated population and should be consistently performed.

Booster effect of Sabin poliomyelitis vaccine.

Studies were carried out on 86 children aged 1-14 years who had titres of antibodies against poliovirus type 3 lower than 1: 32 and against type 2 higher than 1: 4. After a booster dose of poliomyelitis vaccine type 2+3, seroconversion took place in 44 (90%) of 49 children whose original titre was lower than 1: 4 and the geometrical mean titre increased to 1: 244. Of 37 children with low original titres of antibodies against type 3, i.e., 1: 4, 1: 8, or 1: 16, the titre increased fourfold or more in 31 (84%) and the geometrical mean titre rose to 1: 175. In 11 children (13%), no significant increase in titre took place.

Occurrence of antibodies to type 2 herpes simplex virus in the sera of town population.

In order to obtain a more detailed knowledge of the ecology of genital herpesvirus in Czechoslovak geographic and socioeconomic conditions, a total of 1 246 sera of town population, collected by the method of random selection from persons of different age groups in the town of Ostrava were examined in microneutralization reaction for antibodies to type 2 and type 1 herpes simplex virus. Antibodies to HSV-1 were present even in the youngest age groups 0--4 and 5--9 and positive findings in the older age groups ranged from 52 to 82% while antibodies to type 2 herpesvirus were found for the first time at the age of 14 (in one case); in adult persons they occurred in 17--26%. The mentioned results correspond to the sexual manner of transmission of genital herpesvirus and are in keeping with published findings.