Prevalence of asymptomatic malaria, sub microscopic parasitaemia and anaemia in Korogwe District, north-eastern Tanzania.

Background: Asymptomatic malaria infections largely remain undetected and act as a reservoir for continuous transmission. Objectives: To determine the prevalence of sub-microscopic asymptomatic malaria infections and anaemia in two rural settings of Korogwe District north-eastern Tanzania. Methods: A cross-sectional malariometric survey involving individuals aged 0-19 years was conducted in June 2018 in the two rural villages. Venous blood was collected from eligible study participants for estimation of haemoglobin level, detection of malaria by RDT, quantification of malaria parasitaemia by microscopy, as well as dried blood spot (DBS) for determining sub-microscopic infections by PCR targeting the small subunit of the ribosomal ribonucleic acid (ssrRNA) of human Plasmodium. Results: Out of 565 individuals tested, 211 (37.3%) were malaria positive based on RDT, whereas only 81 (14.3%) were positive by microscopy. Three out of 206 (1.5%) RDT/microscopy negative samples were P. falciparum positive by PCR. Of the 211 RDT and 81 microscopies positive, 130 (61.6%) and 33 (40.7%), respectively, were defined as being asymptomatic. Of the 565 individuals, 135 (23.9%) were anaemic (haemoglobin < 11 g/dL) out of which 5.2% were severely anaemic. The risk of being anaemic was significantly higher among individuals with asymptomatic malaria as compared to those without malaria as confirmed by RDT (AOR = 2.06 (95% CI: 1.32-3.20) while based on microscopic results there was no significant differences observed (AOR = 2.09, 95% CI: 0.98-4.47). Conclusion: Asymptomatic malaria is associated with an increased risk of having anaemia in the study communities. The findings highlight the need for targeted interventions focusing on asymptomatic infections which is an important risk factor for anaemia in the community and act as a source of continued transmission of malaria in the study area. [ABSTRACT FROM AUTHOR]