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Variation of malaria transmission and morbidity with altitude in Tanzania and with introduction of alphacypermethrin treated nets

Maxwell, A.C., Chambo, W., Mwaimu, M., Magogo, F., Carneiro, A.I. and Curtis, F.C. (2003) Variation of malaria transmission and morbidity with altitude in Tanzania and with introduction of alphacypermethrin treated nets. Malaria Journal, 2 (28). pp. 1-9.

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Background: Highland areas with naturally less intense malaria transmission may provide models
of how lowland areas might become if transmission was permanently reduced by sustained vector
control. It has been argued that vector control should not be attempted in areas of intense
Methods: Mosquitoes were sampled with light traps, pyrethrum spray and window exit traps.
They were tested by ELISA for sporozoites. Incidence of malaria infection was measured by clearing
existing infections from children with chlorproguanil-dapsone and then taking weekly blood
samples. Prevalence of malaria infection and fever, anaemia and splenomegaly were measured in
children of different age groups. All these measurements were made in highland and lowland areas
of Tanzania before and after provision of bednets treated with alphacypermethrin.
Results: Entomological inoculation rates (EIR) were about 17 times greater in a lowland than a
highland area, but incidence of infection only differed by about 2.5 times. Malaria morbidity was
significantly less prevalent in the highlands than the lowlands. Treated nets in the highlands and
lowlands led to 69–75% reduction in EIR. Malaria morbidity showed significant decline in younger
children at both altitudes after introduction of treated nets. In children aged 6–12 the decline was
only significant in the highlands
Conclusions: There was no evidence that the health benefits to young children due to the nets in
the lowlands were "paid for" by poorer health later in life. Our data support the idea of universal
provision of treated nets, not a focus on areas of natural hypo-endemicity.

Item Type: Article
Keywords: Malaria transmission,Tanzania,alphacypermethrin treated nets, Malaria control
Subjects: Malaria > Vector control
Divisions: Ifakara Health Institute > Biomedical
Depositing User: Mr Joseph Madata
Date Deposited: 25 Aug 2012 10:57
Last Modified: 25 Aug 2012 10:57

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