Sero-epidemiologic study of the Epstein--Barr virus infectivity in a healthy Cuban population.

The indirect immunofluorescence test was used to study the level of humoral antibodies against viral capsid antigen of the Epstein--Barr virus (VCA-EBV), and early antigen (EA) in the sera of 322 healthy donors of the Havana City province. The age of donors ranged from several months up to 95 years. The results obtained indicate that the healthy population of Cuba is infected by EBV as well as in other countries, even though the spread and the course of infection have its specific characteristics. In the early childhood population group (3--4 years old) the infection is relatively more frequent (73%) than in adults (62--77%), despite the fact that the country is located in the tropical zone. In all the studied age groups the geometric mean titers (GMT) of antibodies were found to be lower in comparison with the other populations studied. The increase of EBV-antibody levels in the group of donors above 55 years of age, together with a large number of seropositive individuals, increase in the number of persons with high anti-VCA-EBV antibody titers (1 : 160), agrees with the results obtained by other investigators. This may be associated with some form of depression of cell-mediated immune response. Infectious mononucleosis-morbidity in the studied age groups was found to be low in 3--4-year- and 15--19-year-old age groups, where higher levels of antibodies against EA of EBV were found.