Seroepidemiological evaluation of malaria in Mayotte Island (Comoro Archipelago), 1984-1988.

In the context of a research programme on the immunology of malaria in the islands of the south-west of the Indian Ocean, seroepidemiological studies by means of sampling surveys have been carried out annually in Mayotte Island (Comoro Archipelago) from 1984 to 1988. Apart from the transient character of the increases in rates in the wake of the epidemic outbreak of 1984, the evolution of the antibody geometric mean recoprocal titre (GMRT) by age reveals a negativation of population at large, fast only in the younger age-group. At such a high level of negativation, the GMRT does not lend itself to interpretation. In the older age-groups the negativation becomes so slow as to render a yearly periodicity too short to show differences. The correlation between GMRT and age that persisted over the five-year period suggests that the evolution of the rates according to age follows a predetermined model. The epidemiological interpretation of purely serological data, except for a general indication of the trend, is however difficult, specially in an archipelago where the levels of malaria transmission are not the same in the different islands, but where inter-island migration is quite important.