Background The C580Y mutation in the Plasmodium falciparum kelch13 gene is the most commonly observed variant in artemisinin-resistant isolates in the Greater Mekong Subregion (GMS). Until 2017, it had not been identified outside the GMS, except for Guyana/Amazonia. In 2017, three parasites carrying the C580Y mutation were identified in Papua New Guinea (PNG). As the C580Y allele rapidly spread in the GMS, there is concern that this mutant is now spreading in PNG. Methods In 2020, a cross-sectional survey was conducted at two clinics in Wewak, PNG. Symptomatic patients infected with P. falciparum were treated with artemether plus lumefantrine following a national treatment policy. Blood samples were obtained before treatment, and polymorphisms in kelch13, pfcrt, and pfmdr1 were determined. Parasite positivity was examined on day 3. The results were compared with those of previous studies conducted in 2002, 2003, and 2016–2018. Results A total of 94 patients were included in this analysis. The proportion of C580Y was significantly increased (2.2% in 2017, 5.7% in 2018, and 6.4% in 2020; p = 4.2 × 10–3). A significant upward trend was observed in the wild-type proportion for pfcrt (1.9% in 2016 to 46.7% in 2020; p = 8.9 × 10–16) and pfmdr1 (59.5% in 2016 to 91.4% in 2020; p = 2.3 × 10–6). Among 27 patients successfully followed on day 3, including three with C580Y infections, none showed positive parasitaemia. Conclusions Under the conditions of significant increases in pfcrt K76 and pfmdr1 N86 alleles in PNG, the increase in kelch13 C580Y mutants may be a warning indicator of the emergence of parasites resistant to the currently used first-line treatment regimen of artemether plus lumefantrine. Therefore, nationwide surveillance of molecular markers for drug resistance and assessment of its therapeutic effects are important.

BackgroundThe C580Y mutation in Plasmodium falciparum kelch13 (pfk13) is the most commonly observed variant in artemisinin-resistant isolates in the Greater Mekong Subregion (GMS). Until 2017, it had not been identified outside GMS, except for Guyana. In 2017, we identified three parasites carrying the C580Y mutation in Papua New Guinea (PNG). As the C580Y allele rapidly spread in the GMS, there is concern that this mutant is now spreading in PNG. MethodsIn 2020, we conducted a cross-sectional survey at two clinics in Wewak, PNG. Symptomatic patients infected with P. falciparum were treated with artemether plus lumefantrine following a national treatment policy. Blood samples were obtained before treatment, and polymorphisms in pfk13, pfcrt, and pfmdr1 were determined. Parasite positivity was examined on day 3. ResultsA total of 94 patients were included in this analysis. The prevalence of C580Y was significantly increased (2.2% in 2017, 5.7% in 2018, and 6.4% in 2020; p = 4.2×10-3). A significant upward trend of wild-type prevalence was found for pfcrt (1.9% in 2016 to 46.7% in 2020; p = 8.9×10-16) and pfmdr1 (59.5% in 2016 to 91.4% in 2020; p = 2.3×10-6). Among 26 patients, including three with C580Y infections successfully followed on day 3, none showed positive parasitemia. ConclusionsUnder the conditions of significant increases in pfcrt K76 and pfmdr1 N86 alleles in PNG, the increase in pfk13 C580Y mutants may be a warning indicator of the emergence of parasites resistant to the currently used first-line treatment regimen of artemether plus lumefantrine. Therefore, nationwide surveillance of molecular markers for drug resistance and assessment of its therapeutic effect, are important.

Yosuke DAICHO (Stu.Mem.), Yasuhiro KAWASHIMA (Stu. Mem.), Yinggang BU (Mem.), Tutomu MIZUNO (Mem.), Ryosuke MORIKAWA The wireless power transfer is a technique to send electricity without having the mechanical point of contact. The wireless power transfer using magnetic resonant coupling has been studied. The charge to a cell-phone has already been possible by Wireless power transfer. Qi standards are used for wireless power transfer well. The output is less than 5 W. Frequency to use is 110-205 kHz. A wireless power transfer system having the output about 40 W will be necessary in future to charge an electric tool. In this paper, we performed wireless power transfer of output electricity 40 W using the magnetic resonant coupling. Transmission efficiency at 40 W transmission was measured. Also, we measured the radiation electromagnetic field at 40 W transmission. As a result, the efficiency between the coils achieved 91.7 %. The radiation electromagnetic field was less than guidelines on ICNIRP.Keywords: wireless power transfer, magnetic resonant coupling, Qi, radiation electromagnetic field, ICNIRP.