Malaria parasitemia among blood donors in Uganda

Abstract

Background: Malaria remains a leading transfusion associated infectious risk in endemic areas. However, the prevalence of malaria parasitemia has not been well characterized in blood donor populations. This study sought to determine the prevalence of Plasmodium in red blood cell (RBC) and whole blood (WB) units after the rainy season in Uganda.

Methods and materials: Between May and July 2018, blood was collected from the sample diversion pouch of 1000 WB donors in Kampala and Jinja, Uganda. The RBC pellet from ethylenediamine tetraacetic acid (EDTA) anticoagulated blood was stored at -80°C until testing. DNA was extracted and nested PCR was used to screen samples at the genus level for Plasmodium, with positive samples further tested for species identification.

Results: Malaria parasitemia among asymptomatic, eligible blood donors in two regions of Uganda was 15.4%; 87.7% (135/154) of infections were with P. falciparum, while P. malariae and P. ovale were also detected. There were 4.3% of blood donors who had mixed infection with multiple species. Older donors (>30 years vs. 17-19 years; aPR = 0.31 [95% CI = 0.17-0.58]), females (aPR = 0.60 [95% CI = 0.42-0.87]), repeat donors (aPR = 0.44 [95% CI = 0.27-0.72]) and those donating near the capital city of Kampala versus rural Jinja region (aPR = 0.49 [95% CI = 0.34-0.69]) had a lower prevalence of malaria parasitemia.

Conclusions: A high proportion of asymptomatic blood donors residing in a malaria endemic region demonstrate evidence of parasitemia at time of donation. Further research is needed to quantify the risk and associated burden of transfusion-transmitted malaria (TTM) in order to inform strategies to prevent TTM.

Fig. 1.

A map of Uganda Blood Transfusion Service blood processing and collection sites around the country and the monthly rainfall data for Uganda in 2018. A, a map showing the six blood collection (circle outline) and eight blood collection and processing centers (solid circle) across Uganda. The sites evaluated in this study were Kampala and Jinja in central Eastern Uganda (in red). The distance between Buyende and Jinja is ~60 miles. Regions that contributed at least 20 donor samples are indicated with an X. Wakiso (malaria prevalence, 15.0%), Mpigi (12.0%) and Mukono (10.3%) border Kampala and have higher malaria prevalence compared to samples collected at the UBTS headquarters in central Kampala (4.6%). Buyende (46.9%) had 64 donor samples that were sent to both Jinja (n = 34) and Kampala (n = 30) collection sites. B, a graph showing the rainfall data for 2018 with the 2 months preceding sample collection corresponding to the rainy season and the 3 months where samples were collected for malaria testing.