Co-infections with Babesia microti and Plasmodium parasites along the China-Myanmar border

Background:Babesiosis is an emerging health risk in several parts of the world.However,little is known about the prevalence of Babesia in malaria-endemic countries.The area along the China-Myanmar border in Yunnan is a main endemic area of malaria in P.R.China,however,human infection with Babesia microti(B.microti)is not recognized in this region,and its profile of co-infection is not yet clear.Methods:To understand its profile of co-infections with B.microti,our investigation was undertaken in the malaria-endemic area along the China-Myanmar border in Yunnan between April 2012 and June 2013.Four parasite species,including B.microti,Plasmodium falciparum(P.falciparum),P.vivax,and P.malariae,were identified among 449 suspected febrile persons detected by nested polymerase chain reaction(PCR)assay based on small subunit ribosomal ribonucleic acid(RNA)genes of B.microti and Plasmodium spp.Results:Of all the collected samples from febrile patients,mono-infection with B.microti,P.vivax,P.falciparum,and P.malariae accounted for 1.8%(8/449),9.8%(44/449),2.9%(13/449),and 0.2%(1/449),respectively.The rate of mixed infections of B.microti with P.falciparum or P.vivax are both 0.2%(1/449),and mixed infections of P.falciparum and P.vivax accounted for 1.1%(5/449).Conclusions:This report supports the hypothesis that babesiosis caused by B.microti is emerging along the China-Myanmar border in the Yunnan province,P.R.China,but it was ignored because of low parasitemia or mixed infection with Plasmodium spp.More sensitive and specific diagnosis methods are needed to find the rapid response mechanism of emergency for babesiosis and malaria co-prevalence areas.

Malaria control along China-Myanmar Border during 2007–2013: an integrated impact evaluation

Background:Implementing effective interventions remain a lot of difficulties along all border regions.The emergence of artemisinin resistance of Plasmodium falciparum strains in the Greater Mekong Subregion is a matter of great concern.China has effectively controlled cross-border transmission of malaria and artemisinin resistance of P.falciparum along the China-Myanmar border.Methods:A combined quantitative and qualitative study was used to collect data,and then an integrated impact evaluation was conducted to malaria control along the China-Myanmar border during 2007-2013.Results:The parasite prevalence rate(PPR)in the five special regions of Myanmar was decreased from 13.6%in March 2008 to 1.5%in November 2013.Compared with the baseline(PPR in March 2008),the risk ratio was only 0.11[95%confidence interval(CI),0.09-0.14]in November 2013,which is equal to an 89%reduction in the malaria burden.Annual parasite incidence(API)across 19 Chinese border counties was reduced from 19.6 per 10000 person-years in 2006 to 0.9 per 10000 person-years in 2013.Compared with the baseline(API in 2006),the API rate ratio was only 0.05(95%CI,0.04-0.05)in 2013,which equates to a reduction of the malaria burden by 95.0%.Meanwhile,the health service system was strengthened and health inequity of marginalized populations reduced along the international border.Conclusion:The effective collaboration between China,Myanmar and the international non-governmental organization promptly carried out the core interventions through simplified processes.The integrated approaches dramatically decreased malaria burden of Chinese-Myanmar border.

Polymorphisms of potential drug resistant molecular markers in Plasmodium vivax from China-Myanmar border during 2008-2017

Background:Plasmodium vivax remains the predominant species at the China–Myanmar border,imposing a major challenge to the recent gains in regional malaria elimination.To closely supervise the emerging of drug resistance in this area,we surveyed the variations in genes potentially correlated with drug resistance in P.vivax parasite and the possible drug selection with time.Methods:A total of 235 P.vivax samples were collected from patients sufering uncomplicated malaria at Yingjiang,Tengchong,and Longling counties,and Nabang port in China,Yunnan province,and Laiza sub-township in Myanmar,from 2008 to 2017.Five potential drug resistance genes were amplifed utilizing nested-PCR and analyzed,including pvdhfr,pvdhps,pvmdr1,pvcrt-o,and pvk12.The Pearson’s Chi-squared test or Fisher’s exact test were applied to determine the statistical frequency diferences of mutations between categorical data.Results:The pvdhfr F57I/L,S58R,T61M and S117T/N presented in 40.6%,56.7%,40.1%,and 56.0% of the sequenced P.vivax isolates,and these mutations signifcantly decreased with years.The haplotype formed by these quadruple mutations predominated in Yingjiang,Tengchong,Longling and Nabang.While a mutation H99S/R(56.6%)dominated in Laiza and increased with time.In pvdhps,the A383G prevailed in 69.2% of the samples,which remained the most prevalent haplotype.However,a signifcant decrease of its occurrence was also noticed over the time.The S382A/C and A553G existed in 8.4% and 30.8% of the isolates,respectively.In pvmdr1,the mutation Y976F occurred at a low frequency in 5/232(2.2%),while T958M was fxed and F1076L was approaching fxed(72.4%).The K10 insertion was detected at an occurrence of 33.2% in pvcrt-o,whereas there was no signifcant diference among the sites or over the time.No mutation was identifed in pvk12.Conclusions:Mutations related with resistance to antifolate drugs are prevalent in this area,while their frequencies decrease signifcantly with time,suggestive of increased susceptibility of P.vivax parasite to antifolate drugs.Resistance to chloroquine(CQ)is possibly emerging.However,since the molecular mechanisms underneath CQ resistance is yet to be better understood,close supervision of clinical drug efciency and continuous function investigation is urgently needed to alarm drug resistance.

Whole-genome sequencing and analysis of Plasmodium falciparum isolates from China-Myanmar border area

Background:China has made progress in malaria control and aims to eliminate malaria nationwide,but implementing effective interventions along the border regions remain a huge task.The Plasmodium falciparum cases imported from Southeast Asia has frequently reported especially in the China-Myanmar border(CMB)area.Though,information is scant on P.falciparum genetic variability in this area.Methods:This study reported P.falciparum isolates genome sequence of six clinical isolates in the CMB area.Furthermore,we estimated the nucleotide diversity,Watterson’s estimator and Tajima’s D value for the whole genome mutation rate in slide window.Results:Our data were aligned onto 96.05-98.61%of the reference 3D7 genome in high fold coverages.Principal component analysis result showed that P.falciparum clustered generally according to their geographic origin.A total of 91 genes were identified as positive selection with Ka/Ks ratio significantly higher than 1,and most of them were multigene families encoding variant surface antigens(VSAs)such as var,rif and stevor.The enrichment of the positive selection on VSA genes implied that the environment complexity subjected CMB’s P.falciparum to more pressure for survival.Conclusions:Our research suggests that greater genetic diversity in CMB area and the positive selection signals in VSA genes,which allow P.falciparum to fit the host immune system well and aggravate the difficulty of treatment.Meanwhile,results obtained from this study will provide the fundamental basis for P.falciparum population genomic research in CMB area.

Exploring the Design Control of Gated Communities:Potentials and Approaches

From the perspective of urban design control, the study investigates the possibilities and approaches to reduce negative infl uences of gated communities, directly or indirectly, through effective planning policies or design strategies during the construction process. Based on empirical research of embedded-single case studies, it centers on three factors: enclosure scale, border effect, and shared facilities of gated communities, and discusses the necessity and feasibility to apply design control in gated communities as seen from different interest groups, i.e., developers, managers, users, and maintainers. Accordingly, it proposes several key design factors and implementation approaches to promote the integration of gated communities and "private-owned public space" into an urban social and spatial network.