Prevalence Of Asymptomatic And Submicroscopic Malaria Parasitaemia In Korogwe, North-Eastern Tanzania

ABSTRACT

Despite the intensification in malaria control interventions, malaria still remains a major public health problem in malaria-endemic settings. Asymptomatic infections that largely remain undetected act as a reservoir of transmission jeopardizing the current control efforts. The aim of this study was to determine the prevalence of asymptomatic malaria infection, anaemia and submicroscopic parasitaemia in individuals of Korogwe District, a malaria-endemic setting in north-eastern Tanzania. A community-wide cross-sectional malaria metric survey involving participants aged 0-19 years was conducted in two villages of Korogwe District, a malaria-endemic setting in north-eastern Tanzania. Parasite DNA was extracted from dried blood spots (DBS) collected during the survey. Detection of submicroscopic malaria infection from slide negative cases was done by Plasmodium genus and speciesspecific nucleotide amplification method. Out of 565 participants, 211 (37.41%, 95% CI: 33.99-41.49%) had malaria infection after testing using malaria rapid diagnostic test (mRDT), whereas only 81 (14.38%, 95% CI: 11.71-17.54%) were malaria positive by microscopy. Of the 565 participants, 130 (23.0%, 95% CI: 19.71-26.67%) and 33 (5.84%, 95% CI: 4.18-8.11%) had asymptomatic malaria based on mRDT and microscopy, respectively. Out of 565 participants, 135 (23.89%, 95% CI: 20.54-27.59%) were anaemic. Three out of 206 (1.5%, 95% CI: 0.47-4.46%) samples that were malaria negative by microscopy were found to be positive when analyzed by polymerase chain reaction (PCR), indicating the presence of submicroscopic malaria. Multivariate logistic regression analysis for predictors of anaemia showed that, participants aged between 5-9 and 10-14 years were significantly associated with asymptomatic malaria and anaemia (adjusted odds ratio (AOR) = 0.6, 95% CI: 0.37-0.98, p = 0.04) and (AOR = 0.32, 95% CI: 0.14-0.75, p = 0.01), respectively. The current study observed that asymptomatic malaria is much more prevalent in participants aged above five years. Furthermore, participants aged 5-14 iii years were at risk of asymptomatic malaria associated with anaemia. A low proportion of submicroscopic parasitaemia was observed in this study. The findings highlight the need for targeted interventions focusing on those participants aged above five years in malaria control interventions.