The antibody responses to adult-worm antigens of Schistosoma haematobium, among infected and resistant individuals from an endemic community in southern Ghana.

Antibody responses to antigens from adult Schistosoma haematobium were investigated in an endemic community in Ghana, using microplate-ELISA. The results of a survey of egg output in urine and of a questionnaire-based investigation of water-contact activities were used to select 'endemic normal' (EN) and patently infected (PI) individuals as subjects. The plasma levels of antibodies reacting with the adult-worm antigens were determined and compared and the correlations between these levels and the age, water-contact index and egg output of each subject were evaluated. Compared with the EN subjects, the PI generally had higher levels of anti-worm IgG and IgE but lower levels of anti-worm IgA. When the data for the EN and PI groups were combined, the levels of anti-worm IgG and IgE were found to be positively correlated with egg output and with each other. Whichever the antibody class considered, levels of anti-worm antibodies were never negatively correlated with egg output. These results indicate that anti-worm IgE and IgG could be used as markers to reflect current infection intensity, and that anti-worm antibodies may not act as protective antibodies in the natural course of urinary schistosomiasis.

Seasonal characteristics of malaria infection in under-five children of a rural community in southern Ghana.

In a quarterly survey of malaria infection in the under-five children conducted at Gomoa Onyadze/Otsew Jukwa, a rural community in the Central Region of Ghana from December, 1986 to September, 1987, crude parasite rates ranged from 19.6 to 33.5 per cent in the dry season (December and March) and 33.0 to 44.0 per cent in the wet season (June and September). P. falciparum was the predominant parasite species by parasite formula analysis with higher rates in the rainy season (94.2 to 95.8 per cent) compared to that of the dry season (51.4 to 78.8 per cent). P. malariae (20.4 per cent), P. ovale (2.7 per cent) and mixed infection rates were higher in the dry season (December and March). As high as 30.4 to 44.8 per cent of positive parasite slides had parasite density of above 3200 per microliter of blood (above class 6 degree of parasitaemia). Depending on the season 7.2-27.3 per cent of children had parasite density above 25,600 per microliter of blood (above class 10 degree of parasitaemia).