Persistent Positivity of Rapid Diagnosis Test Kits of Histidine Rich Protein II and III (HRP II and III) antigens after treatment with malaria drugs

The study was carried out to determine the Persistent Positivity (PP) of Histidine Rich Protein II and Histidine Rich Protein III (HRPII and HRPIII) antigens after treatment with malaria drugs. Three hundred and sixty (360) blood samples were collected from individuals of different ages and sexes. The samples were collected by pricking the finger with a sterile lancet, and blood was transferred into the sample well on the RDT cassette. Two drops of buffer were added, and the results were read after 15 min. Of the 360 samples, 200 tested positive for malaria using Rapid Diagnostic Test kits (RDTs) for HRPII and HRPIII. The patients were followed up after malaria treatment. At day 1-4 post-treatment, both HRPII and HRPIII rates of PP were 100%. HRPII and HRPIII started dropping from days 5-9 post-treatment, and the percentage positivity dropped to 28.8% and 9.1%, respectively, after 10-14 days post-treatment. At day 15-19 post-treatment, antigens of HRPII and HRPIII were significantly low at 1.5% and 0.0%, respectively. The age group of ≥50 years had the highest persistence of 7.1% for both HRPII and HRPIII, 15-19 days after malarial treatment. The persistent positivity between the group that received Artemisinin-based Combination Therapy (ACT) and Sulfadoxine Pyrimethamine (SP) from day 1 to 4 was 100% with HRPII. Males had 2.1% and 0% PP, in contrast to females, with 4.8% and 1.9% of HRPII and HRPIII, respectively. These findings indicate that the PP of RDTs varies according to age, sex, and type of drug used for malaria treatment.