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O'Riordan, Sean
(2008).
DOI: https://doi.org/10.21954/ou.ro.0000fa4f
Abstract
Haemoglobin E is the most common single mutation haemoglobinopathy worldwide, presumably due to selective pressure from malaria. There is no good clinical data to support this hypothesis, however, and the laboratory data is conflicting. This thesis presents the results of prevalence studies, cross sectional association studies and a case control study undertaken to examine the relationship between haemoglobin E and malaria in southern Vietnam. The S’Tiếng ethnic group demonstrated a high prevalence of HbE and alpha thalassaemia, whilst the majority Kinh, and minorities from the north of Vietnam, had a low prevalence. The S’Tiếng also appeared to experience a higher burden of malaria infection, as determined by malaria parasite point prevalence and the age pattern of severe disease. There was no association between haemoglobin E and malaria in the cross sectional surveys once correction was made for ethnicity. A knowledge, attitudes and practice survey demonstrated a small difference in the proportion of S’Tiếng using bednets compared to other ethnic groups, but no other significant differences to account for their higher malaria burden. Malaria control programmes, which had been very successful elsewhere in Vietnam, have seemed slow to take effect in the central and southern highlands, particularly amongst ethnic minority groups. There appeared to be some success over the course of the study, however, with the result that recruitment to the case control study of severe malaria was slow, and there were insufficient cases from populations with high prevalences of haemoglobin E to draw any firm conclusions. The data gathered demonstrate a trend towards susceptibility to moderate and severe disease considered together, however, suggesting that any protective effect is likely to be modest.