Fine-Scale Spatial Prediction on the Risk of Plasmodium vivax Infection in the Republic of Korea.

BACKGROUND: Malaria elimination strategies in the Republic of Korea (ROK) have decreased malaria incidence but face challenges due to delayed case detection and response. To improve this, machine learning models for predicting malaria, focusing on high-risk areas, have been developed. METHODS: The study targeted the northern region of ROK, near the demilitarized zone, using a 1-km grid to identify areas for prediction. Grid cells without residential buildings were excluded, leaving 8,425 cells. The prediction was based on whether at least one malaria case was reported in each grid cell per month, using spatial data of patient locations. Four algorithms were used: gradient boosted (GBM), generalized linear (GLM), extreme gradient boosted (XGB), and ensemble models, incorporating environmental, sociodemographic, and meteorological data as predictors. The models were trained with data from May to October (2019-2021) and tested with data from May to October 2022. Model performance was evaluated using the area under the receiver operating characteristic curve (AUROC). RESULTS: The AUROC of the prediction models performed excellently (GBM = 0.9243, GLM = 0.9060, XGB = 0.9180, and ensemble model = 0.9301). Previous malaria risk, population size, and meteorological factors influenced the model most in GBM and XGB. CONCLUSION: Machine-learning models with properly preprocessed malaria case data can provide reliable predictions. Additional predictors, such as mosquito density, should be included in future studies to improve the performance of models.

A Profile of Glucose-6-Phosphate Dehydrogenase Variants and Deficiency of Multicultural Families in Korea.

Vivax malaria incidence in Korea is now decreased and showing a low plateau. Nowadays, vivax malaria in Korea is expected to be successfully eliminated with anti-malaria chemotherapy, primaquine, and vector control. The glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with potential hemolytic anemia after primaquine administration. This inborn disorder has a pivotal polymorphism with genetic variants and is the most prevalent X-chromosome-linked disorder. The prevalence of G6PD deficiency was previously reported negligible in Korea. As the population of multicultural families pertaining marriage immigrants and their adolescents increases, it is necessary to check G6PD deficiency for them prior to primaquine treatment for vivax malaria. The prevalence of G6PD variants and G6PD deficiency in multicultural families was performed in 7 counties and 2 cities of Jeollanam-do (Province), Gyeonggi-do, and Gangwon-do. A total of 733 blood samples of multicultural family participants were subjected to test the phenotypic and genetic G6PD deficiency status using G6PD enzyme activity quantitation kit and PCR-based G6PD genotyping kit. The G6PD phenotypic deficiency was observed in 7.8% of male adolescent participants and 3.2% of materfamilias population. Based on the PCR-based genotyping, we observed total 35 participants carrying the mutated alleles. It is proposed that primaquine prescription should seriously be considered prior to malaria treatment.

An Epidemiological Analysis of 28 Vivax Malaria Cases in Gimpo-si, Korea, 2020.

Since 1993, vivax malaria has been recognized as a public health burden in Korea. Despite of pan-governmental malaria-control efforts and the dramatic reduction in the burden of this disease over the last 10 years, vivax malaria has not been well controlled and has remained continuously endemic. We focused interviewed and examined the charts of 28 confirmed vivax malaria patients given malarial therapy for whom daily records were kept from Gimpo-si, Gyeonggido of Korea. Various epidemiological characteristics of vivax malaria, including the incubation period, medication used, and recurrence, and an evaluation of the parasitic characteristics from the focused interviews of patients from this region are described here. Most of the participants indicated the 3 most common symptoms of malaria (headache, chills and fever). Of the 28 cases, 2 experienced a second attack and there were 17 and 11 cases with short- and long-term incubation periods, respectively, yielding a short-term to long-term ratio of 1.5. Based on the parasitemia stages, most of the participants were tested at 5 to 7 days (11 cases) and 7 to 15 days (11 cases) after initial wave of asexual parasites. In conclusion, public health authorities should consider developing management measures to decrease the time lag for diagnosis and drafting unified and robust guidelines for drug use for malaria and drawing up unified and robust guidelines on the use of medication for malaria. It also suggests that routine monitoring, surveillance, and precise medical surveys in high-risk vivax malaria endemic areas are pivotal to controlling this persistent public disease and finally eliminating it from Korea.

Knowledge, Attitudes and Perceptions Regarding Endemic Vivax Malaria in Inhabitants and Patients in Two Cities of Northern Gyeonggi-do, Korea, 2020.

An understanding of the knowledges, attitudes and perceptions of different populations is key for public health policy makers. Here, a survey was performed on knowledge, attitudes, and perceptions about malaria diagnosis, prevention, control, and treatment. The 407 survey participants included both uninfected inhabitants and patients from 2 cities (Gimpo- and Paju-si) of Northern Gyeonggi-do, known as high-risk areas for vivax malaria. We used community-based study design and non-probability sampling method using the primary data. Association between variables were tested using χ2-tests. In general, the information on malaria reported by the participants in this study was unsystematic and included inaccurate details. The knowledge of malaria symptoms, identified as headache, chills and fever, was high, but the surveyed community lacks knowledge of the specific medications used for malaria treatment, with a large number of respondents having no knowledge of any form of medication. Survey questions with high correct answer rates included questions about easy treatment of malaria in Korea, the high daytime activity of malaria-borne mosquitoes, and the infection risk posed by outdoor activities. However, a large portion of the respondents was unable to provide simple medical and biological information about the disease. This study aimed to comprehensively evaluate the knowledge, attitude, and practical behavior of the surveyed community with respect to malaria and the implications reported here could be applicable to other malaria endemic areas in Korea.

A randomized, open-label, crossover study to compare the safety and pharmacokinetics of two tablet formulations of tenofovir (tenofovir disoproxil and tenofovir disoproxil fumarate) in healthy subjects.

PURPOSE: This study was performed to compare the pharmacokinetic properties and assess bioequivalence for the test formulation (HUG116 tablet; tenofovir disoproxil) and reference formulation (Viread tablet; tenofovir disoproxil fumarate). MATERIALS AND METHODS: A randomized, open-label, single-dosing, two-treatment, two-period, two-sequence cross-over study was conducted in 50 healthy subjects. All subjects were randomly assigned to one of the two sequences, and they received a single dose of test or reference formulation in the first period and the alternative formulation during the next period under fasting conditions. Serial blood samples for pharmacokinetic evaluation were collected up to 72 hours post dose, and the pharmacokinetic parameters were estimated by noncompartmental methods. Throughout the study, tolerability was assessed based on adverse events, vital signs, and clinical laboratory tests. RESULTS: The test formulation showed similar pharmacokinetic profiles to those of the reference formulation. The geometric mean ratio and 90% confidence interval (CI) of the test formulation to the reference formulation for maximum plasma concentration (Cmax) was 0.93 (0.87 - 0.99), and the corresponding value for the area under the concentration-time curve from time zero to time of last quantifiable concentration (AUCt) was 0.94 (0.89 - 0.99). Both CIs were within the conventional bioequivalence range of 0.8 - 1.25. The tolerability profile was not significantly different between the test and reference formulations. CONCLUSION: This study found that the PKs of the test formulation (HUG116 tablet; tenofovir disoproxil) and reference formulation (Viread tablet; tenofovir disoproxil fumarate) were similar, and the test formulation met the regulatory criteria for assuming bioequivalence with the reference formulation.

Bioequivalence for a Fixed-Dose Combination Formulation of Bazedoxifene and Cholecalciferol Compared With the Corresponding Single Entities Given Together.

A fixed-dose combination (FDC) formulation of bazedoxifene 20 mg and cholecalciferol 8 mg was developed to increase medication compliance and convenience for osteoporosis patients. This study was conducted to demonstrate bioequivalence by comparing the pharmacokinetic (PK) profiles and tolerability of an FDC tablet and the individual component tablets. A randomized, open-label, single-dosing, 2-treatment, 2-period, 2-sequence crossover study was conducted in 52 healthy subjects. All subjects were randomly assigned to 2 sequences, and they received FDC tablets of bazedoxifene and cholecalciferol and individual component tablets. Serial blood samples for PK evaluation were collected up to 24 hours predose and 120 hours postdose, and the PK parameters were estimated by noncompartmental methods. Throughout the study, tolerability was assessed based on adverse events, vital signs, and clinical laboratory tests. Of the enrolled 52 subjects, 47 subjects completed the study. The results, the geometric mean ratios (GMRs) and 90% confidence intervals (90%CIs), of bazedoxifene Cmax and AUC0-t for FDC to single entities given together were 0.98 (0.91-1.05) and 1.02 (0.97-1.07), respectively. The GMRs (90%CIs) of cholecalciferol Cmax and AUC0-t for FDC to single entities given together were 0.96 (0.91-1.00) and 0.94 (0.90-0.99), respectively. Overall, the GMRs (90%CIs) of the PK parameter of bazedoxifene and cholecalciferol fell within the conventional bioequivalence range of 0.8-1.25. There were no clinically significant differences in the safety profile between the 2 treatments. In conclusion, this study confirmed the development of a new FDC drug by demonstrating that the FDC formulation of bazedoxifene and cholecalciferol is biologically equivalent to the coadministered individual formulations.

Pharmacokinetic comparison of two bazedoxifene acetate 20 mg tablet formulations in healthy Korean male volunteers.

Bazedoxifene, used as bazedoxifene acetate, is a selective estrogen receptor modulator that selectively affects the uterus, breast tissue, bone metabolism, and lipid metabolism by antagonizing or enhancing estrogens in the estrogen receptor in the tissue. This study was conducted as an open, randomized, two-period, two-treatment, crossover design to compare the pharmacokinetic (PK) characteristics and tolerability of two bazedoxifene tablets when administered to 50 healthy Korean male volunteers. Enrolled subjects were randomly allocated to 2 sequences of a single oral administration of a test drug and a reference drug, or vice versa with a 14-day washout period between the two doses. Serial blood samples were collected over 96 h for PK analysis. Plasma concentration of bazedoxifene was assayed using liquid chromatography-tandem spectrometry mass. Forty-five participants completed the study with no clinically relevant safety issues. The peak concentrations (Cmax, mean ± strandard deviation) of reference drug and test drug were 3.191 ± 1.080 and 3.231 ± 1.346 ng/mL, respectively, and the areas under the plasma concentration-time curve from 0 to the last measurable concentration (AUClast) were 44.697 ± 21.168 ng∙h/mL and 45.902 ± 23.130 ng∙h/mL, respectively. The geometric mean ratios of test drug to reference drug and their 90% confidence intervals for Cmax and AUClast were 0.9913 (0.8828-1.1132) and 1.0106 (0.9345-1.0929), respectively. The incidence of adverse events between the two formulations was similar. The present study showed that PK and tolerability of two bazedoxifene tablet formulations were comparable when administered to healthy Korean male volunteers. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0003978.