Effect of Plasmodium falciparum parasitaemia on some haematological parameters in adolescent and adult Nigerian HbAA and HbAS blood genotypes.

OBJECTIVE

To compare the susceptibility of HbAA and HbAS blood genotypes to Plasmodium falciparum in human subjects.

DESIGN

Prospective Cross Sectional Study.

SETTINGS

Department of Biochemistry College of Medical Sciences, University of Calabar, Cross Rivers State, Nigeria.

SUBJECTS

A total of 120 individuals comprising 60 subjects (41 males and 19 females) and 60 patients (33 males and 27 females) aged between 15 and 30 years were enlisted in this study.

MAIN OUTCOME MEASURES

The susceptibility of the HbAA and HbAS blood genotypes to Plasmodium falciparum in human subjects was based on the frequency of occurrence of parasitaemia and the accompanying haematological changes in each group.

RESULTS

Among a sample population of 120 subjects and patients, 86 were HbAA and 34 were HbAS representing 72% and 28% of the sample population. Parasites were detected in the red cells of 15 out of the 34 HbAS subjects i.e. 44% of the group or 13% of the sample population. Compared with the control group, the parasitaemic HbAA group had significantly lower PCV and Hb, and significantly higher serum iron, TIBC and transferrin, but a similar percentage transferrin saturation. All the differences were highly significant (p < 0.001). In the parasitaemic HbAS group, PCV and percentage transferrin saturation were slightly lower while TIBC and transferrin were slightly higher when compared with the control. These differences were not significant.

CONCLUSION

The greater susceptibility of HbAA individuals to Plasmodium falciparum malaria and the enhanced severity of an attack in this group maybe due to low red cell membrane resistance to the invading parasite and a non-hypoxic environment within the red cell which enhances its development.