Malaria epidemiology in the Ahafo area of Ghana

Abstract

Background: Plasmodium falciparum malaria remains endemic in sub-Saharan Africa including Ghana. The epidemiology of malaria in special areas, such as mining areas needs to be monitored and controlled. Newmont Ghana Gold Limited is conducting mining activities in the Brong Ahafo Region of Ghana that may have an impact on the diseases such as malaria in the mining area.

Methods: Prior to the start of mining activities, a cross-sectional survey was conducted in 2006/2007 to determine malaria epidemiology, including malaria parasitaemia and anaemia among children < 5 years and monthly malaria transmission in a mining area of Ghana.

Results: A total of 1,671 households with a child less than five years were selected. About 50% of the household heads were males. The prevalence of any malaria parasitaemia was 22.8% (95% CI 20.8-24.9). Plasmodium falciparum represented 98.1% (95% CI 96.2-99.2) of parasitaemia. The geometric mean P. falciparum asexual parasite count was 1,602 (95% CI 1,140-2,252) and 1,195 (95% CI 985-1,449) among children < 24 months and ≥ 24 months respectively. Health insurance membership (OR 0.60, 95% CI 0.45-0.80, p = 0.001) and the least poor (OR 0.57, 95% CI 0.37-0.90, p = 0.001) were protected against malaria parasitaemia. The prevalence of anaemia was high among children < 24 months compared to children ≥ 24 months (44.1% (95% CI 40.0-48.3) and 23.8% (95% CI 21.2-26.5) respectively. About 69% (95% CI 66.3-70.9) of households own at least one ITN. The highest EIRs were record in May 2007 (669 ib/p/m) and June 2007 (826 ib/p/m). The EIR of Anopheles gambiae were generally higher than Anopheles funestus.

Conclusion: The baseline malaria epidemiology suggests a high malaria transmission in the mining area prior to the start of mining activities. Efforts at controlling malaria in this mining area have been intensified but could be enhanced with increased resources and partnerships between the government and the private sector.

Figure 1

Study area map.

Figure 2

Geometric Mean Parasite Density levels in the cohort ((< 24 mo, n = 94; > 24 mo, n = 279).

Figure 3

Haemoglobin levels in the cohort of children (< 24 mo, n = 585; > 24 mo, n = 1035).

Figure 4

Monthly EIRs in Asutifi district (November 2006-August 2007).

Figure 5

Monthly EIRs in Tano N/S district (November 2006-August 2007).

Figure 6

Monthly EIRs by Anopheles gambiae and Anopheles funestus in Asutifi and Tano N/S districts (November 2006-August 2007). Ag = Anopheles gambiae. Af = Anopheles funestus (November 2006-August 2007)