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Drug-resistant Plasmodium vivax malaria impedes efforts to control, eliminate, and ultimately eradicate malaria in Southeast Asia. P. vivax resistance to antifolate drugs derives from point mutations in specific parasite genes, including the dihydropteroate synthase (pvdhps), dihydrofolate reductase (pvdhfr), and GTP cyclohydrolase I (pvgch1) genes. This study aims to investigate the prevalence and spread of drug resistance markers in P. vivax populating the China-Myanmar border. Blood samples were collected from symptomatic patients with acute P. vivax infection. Samples with single-clone P. vivax infections were sequenced for pvdhps and pvdhfr genes and genotyped for 6 flanking microsatellite markers. Copy number variation in the pvgch1 gene was also examined. Polymorphisms were observed in six different codons of the pvdhps gene (382, 383, 512, 549, 553, and 571) and six different codons of the pvdhfr gene (13, 57, 58, 61, 99, 117) in two study sites. The quadruple mutant haplotypes 57I/L/58R/61M/117T of pvdhfr gene were the most common (comprising 76% of cases in Myitsone and 43.7% of case in Laiza). The double mutant haplotype 383G/553G of pvdhps gene was also prevalent at each site (40.8% and 31%). Microsatellites flanking the pvdhfr gene differentiated clinical samples from wild type and quadruple mutant genotypes (F ST= 0.259-0.3036), as would be expected for a locus undergoing positive selection. The lack of copy number variation of pvgch1 suggests that SP-resistant P. vivax may harbor alternative mechanisms to secure sufficient folate.

Imported malaria and recurrent infections are becoming an emerging issue in many malaria non-endemic countries. This study aimed to determine the molecular patterns of the imported malaria infections and recurrence. Blood samples were collected from patients with imported malaria infections during 2016-2018 in Guangxi Zhuang Autonomous Region, China. Next-generation amplicon deep-sequencing approaches were used to assess parasite genetic diversity, multiplexity of infection, relapse, recrudescence, and antimalarial drug resistance. A total of 44 imported malaria cases were examined during the study, of which 35 (79.5%) had recurrent malaria infections within 1 year. The majority (91.4%) had one recurrent malaria episode, whereas two patients had two recurrences and one patient had three recurrences. A total of 19 recurrence patterns (the species responsible for primary and successive clinical episodes) were found in patients returning from malaria epidemic countries. Four parasite species were detected with a higher than usual proportion (46.2%) of non-falciparum infections or mixed-species infections. An increasing trend of recurrence infections and reduced drug treatment efficacy were observed among the cases of imported malaria. The high recurrence rate and complex patterns of imported malaria from Africa to non-endemic countries have the potential to initiate local transmission, thereby undermining efforts to eliminate locally acquired malaria. Our findings highlight the power of amplicon deep-sequencing applications in molecular epidemiological studies of the imported malaria recurrences.

This paper employs the system generalised method of moments approach and panel data of Chinese resource‐based cities at the prefecture level for the period of 2003–2019 to investigate the effects of two types of service sector agglomeration on industrial structure dynamics. The results show that an increase in 'specialised agglomeration' of services would inhibit industrial structure rationalisation and upgrading. However, an increase in 'diversified' agglomeration of services promotes industrial structure upgrading though it also inhibits industrial structure rationalisation. Furthermore, it is also found that an increase in diversified agglomeration would inhibit industrial structure rationalisation in eastern cities and industrial structure upgrading in western cities but promote industrial structure rationalisation and upgrading in central cities. These insights suggest the importance of fostering the appropriate form of service sector agglomeration within resource‐based cities. Leveraging the synergistic linkages between the service sector and other industries could enhance the industrial structure optimisation of resource‐based urban economies. [ABSTRACT FROM AUTHOR]

This article employs structural vector autoregression and local projection methods to examine the impacts of the deterioration in the US–China political relations on bilateral trade between Australia and China. Three scenarios are considered to reflect the evolution of US geopolitical strategies in recent years such as "America First", "China Threat Theory" and "The Protection of US Allies". The simulation results illustrate that worsening the US–China political relations has a negative impact on Australian exports to and imports from China. It is also found that economic conditions in the US play a more important role in the transmission of this impact than those in China and Australia. In addition, various options are explored to check the robustness of the findings in this article. [ABSTRACT FROM AUTHOR]