Limited threat of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletion to the utility of HRP2-based malaria RDTs in Northern Uganda.

BACKGROUND: Rapid diagnostic tests (RDTs) that detect Plasmodium falciparum histidine-rich protein-2 (PfHRP2) are exclusively deployed in Uganda, but deletion of the pfhrp2/3 target gene threatens their usefulness as malaria diagnosis and surveillance tools. METHODS: A cross-sectional survey was conducted at 40 sites across four regions of Uganda in Acholi, Lango, W. Nile and Karamoja from March 2021 to June 2023. Symptomatic malaria suspected patients were recruited and screened with both HRP2 and pan lactate dehydrogenase (pLDH) detecting RDTs. Dried blood spots (DBS) were collected from all patients and a random subset were used for genomic analysis to confirm parasite species and pfhrp2 and pfhrp3 gene status. Plasmodium species was determined using a conventional multiplex PCR while pfhrp2 and pfhrp3 gene deletions were determined using a real-time multiplex qPCR. Expression of the HRP2 protein antigen in a subset of samples was further assessed using a ELISA. RESULTS: Out of 2435 symptomatic patients tested for malaria, 1504 (61.8%) were positive on pLDH RDT. Overall, qPCR confirmed single pfhrp2 gene deletion in 1 out of 416 (0.2%) randomly selected samples that were confirmed of P. falciparum mono-infections. CONCLUSION: These findings show limited threat of pfhrp2/3 gene deletions in the survey areas suggesting that HRP2 RDTs are still useful diagnostic tools for surveillance and diagnosis of P. falciparum malaria infections in symptomatic patients in this setting. Periodic genomic surveillance is warranted to monitor the frequency and trend of gene deletions and its effect on RDTs.

Factors associated with uptake of optimal doses of intermittent preventive treatment for malaria among pregnant women in Uganda: analysis of data from the Uganda Demographic and Health Survey, 2016.

BACKGROUND: The Uganda National Malaria Control Programme recognizes the importance of minimizing the effect of malaria among pregnant women. Accordingly, strategies including intermittent preventive treatment of malaria in pregnancy using sulfadoxine-pyrimethamine (IPTp-SP) have been scaled up. Uptake of IPTp-SP among pregnant women in Uganda, aged 15-49 years who had had a live birth 2 years preceding the 2016 Uganda Demographic and Health Survey (UDHS) was determined and factors associated with the uptake of optimal IPTp-SP doses were identified. METHODS: This was a secondary analysis of the UDHS 2016 dataset. The outcome variable was uptake of IPTp-SP doses among women 15-49 years old who had had a live birth 2 years preceding the survey. Independent variables were residence type, age, marital status, education, wealth status, region of residence, parity, number of antenatal care (ANC) attendance, timing to first ANC visit, and exposure to messages through radio. Logistic regression was used to identify factors associated with the uptake of optimal IPTp-SP doses. RESULTS: Uptake of three or more doses of IPTp-SP was 18%. The likelihood of taking optimal doses of IPTp-SP was increased among those who had attained a secondary-level education (aOR: 1.5, 95% CI 1.04-2.15), those who attended ANC ≥ 4 times (aOR: 1.34, 95% CI 1.12-1.60), and those exposed to radio messages (aOR: 1.23, 95% CI 1.02-1.48). Among those in the age category > 34 years (aOR: 0.70, 95% CI 0.53-0.92), and those who attended first ANC in the third trimester of pregnancy (aOR: 0.58, 95% CI 0.38-0.87) the odds of uptake were decreased. CONCLUSIONS: Education status, exposure to radio messages about health and frequency of ANC attendance were associated with increased uptake while timing of first ANC attendance and being > 34 years were associated with decreased uptake. The findings suggest a need to strengthen behaviour change communication among women of child-bearing age in order to improve uptake of IPTp-SP during pregnancy.