Mosquito densovirus signifcantly reduces the vector susceptibility to dengue virus serotype 2 in Aedes albopictus mosquitoes(Diptera:Culicidae)

Background Dengue virus(DENV)is a major public health threat,with Aedes albopictus being the confrmed vector responsible for dengue epidemics in Guangzhou,China.Mosquito densoviruses(MDVs)are pathogenic mosquitospecifc viruses,and a novel MDV was previously isolated from Ae.albopictus in Guangzhou.This study aims to determine the prevalence of MDVs in wild Ae.albopictus populations and investigate their potential interactions with DENV and impact on vector susceptibility for DENV.Methods The prevalence of MDV in wild mosquitoes in China was investigated using open access sequencing data and PCR detection in Ae.albopictus in Guangzhou.The viral infection rate and titers in MDV-persistent C6/36 cells were evaluated at 12,24,48,72,96,and 120 h post infection(hpi)by indirect immunofuorescence assay(IFA)and real time quantitative PCR(RT-qPCR).The midgut infection rate(MIR),dissemination rate(DR),and salivary gland infection rate(SGIR)in various tissues of MDV-infected mosquitoes were detected and quantifed at 0,5,10,and 15 days post infection(dpi)by RT-PCR and RT-qPCR.The chi-square test evaluated dengue virus serotype 2(DENV-2)and Aedes aegypti densovirus(AaeDV)infection rates and related indices in mosquitoes,while Tukey’s LSD and t-tests compared viral titers in C6/36 cells and tissues over time.Results The results revealed a relatively wide distribution of MDVs in Aedes,Culex,and Anopheles mosquitoes in China and an over 68%positive rate.In vitro,signifcant reductions in DENV-2 titers in supernatant at 120 hpi,and an appar‑ent decrease in DENV-2-positive cells at 96 and 120 hpi were observed.In vivo,DENV-2 in the ovaries and salivary glands was frst detected at 10 dpi in both monoinfected and superinfected Ae.albopictus females,while MDV super‑infection with DENV-2 suppressed the salivary gland infection rate at 15 dpi.DENV-2 titer in the ovary and salivary glands of Ae.albopictus was reduced in superinfected mosquitoes at 15 dpi.Conclusions MDVs is widespread in natural mosquito populations,and replication of DENV-2 is suppressed in MDVinfected Ae.albopictus,thus reducing vector susceptibility to DENV-2.Our study supports the hypothesis that MDVs may contribute to reducing transmission of DENV and provides an alternative strategy for mosquito-transmitted disease control.

The “Paired Learning by Doing” Approach for Capacity Building Derived from the China-UK-Tanzania Pilot Project on Malaria Control During 2015–2018

China’s growing prosperity has led to an increased role in international affairs,particularly in global health cooperation.Alongside sending medical teams abroad,China’s health authority is gradually expanding its South-South cooperation in public health.However,due to a late start in global health initiatives and limited experience in organizing,coordinating,and implementing intervention projects overseas,China still faces significant challenges in global health,particularly in the local context.Recognizing the longstanding partnership between the Chinese and British governments,they have identified global health as a new area of strategic cooperation.In 2012,the former UK Department for International Development(DFID)initiated a new type of health development cooperation project named the China-UK Global Health Support Programme(GHSP).

Application of community-based and integrated strategy to reduce malaria disease burden in southern Tanzania:the study protocol of China-UK-Tanzania pilot project on malaria control

Background:During the past six decades,remarkable success on malaria control has been made in China.The major experience could be shared with other malaria endemic countries including Tanzania with high malaria burden.Especially,China’s 1-3-7 model for malaria elimination is one of the most important refined experiences from many years’efforts and key innovation measures for malaria elimination in China.Methods:The China-UK-Tanzania pilot project on malaria control was implemented from April,2015 to June,2018,which was an operational research with two communities receiving the proposed interventions and two comparable communities serving as control sites.The World Health Organization"Test,Treat,Track"(WHO-T3)Initiative,which calls for every suspected case to receive a diagnostic test,every confirmed case to be treated,and for the disease to be tracked,was integrated with Chinese experiences on malaria control and elimination for exploration of a proper model tailored to the local settings.Application of China’s 1-3-7 model integrating with WHO-T3 initiative and local resources aiming at reducing the burden of malaria in terms of morbidity and mortality by 30%in the intervention communities in comparison with that at the baseline survey.Discussion:The China-UK-Tanzania pilot project on malaria control was that at China’s first pilot project on malaria control in Africa,exploring the feasibility of Chinese experiences by China-Africa collaboration,which is expected that the strategies and approaches used in this project could be potential for scaling up in Tanzania and African countries,and contribute to the acceleration of malaria control and elimination in Africa.

Profile and determinants of delayed care-seeking and diagnosis among patients with imported malaria: a retrospective study in China, 2014–2021

Background: In areas where malaria has been eliminated, delayed care-seeking and diagnosis of imported malaria are constant threats. This study aimed to describe the profile and determinants of delayed care-seeking and diagnosis among patients with imported malaria in China.Methods: This retrospective study assessed surveillance data obtained from 2014 to 2021 in the Chinese provincial-level administrative divisions (PLADs) of Anhui, Henan, Hubei, and Zhejiang, and Guangxi. Epidemiological characteristics were analyzed using descriptive statistics. Furthermore, factors associated with delayed care-seeking and diagnosis among imported malaria cases were identified using multivariate logistic regression.Results: Overall, 11.81% and 30.08% of imported malaria cases had delays in seeking care and diagnosis, respectively. During the study period, there was a decreasing trend in the proportion of imported malaria cases with delayed care-seeking (χ^(2) = 36.099,P < 0.001) and diagnosis (χ^(2) = 11.395,P = 0.001). In multivariate analysis, independent risk factors associated with delayed care-seeking include PLADs (Guangxi as reference), consultations in high-level facilities for the first medical visit, infections with non-Plasmodium falciparum species, and older age. However, PLADs (Guangxi as reference), the purpose of traveling (labour as reference), and infections with non-P. falciparum species increased the risk of delayed diagnosis. Delayed care-seeking (adjusted odds ratio: 1.79,P = 0.001) and diagnosis (adjusted odds ratio: 1.62,P = 0.004) were risk factors for severe disease development.Conclusions: Based on this study’s findings, we strongly advocate for improved access to quality healthcare to reduce the rate of misdiagnosis at the first visit. Infections caused by non-P. falciparum species should be highlighted, and more sensitive and specific point-of-care detection methods for non-P. falciparum species should be developed and implemented. In addition, education programs should be enhanced to reach target populations at risk of malaria infection. All these factors may reduce delayed care-seeking and diagnosis of imported malaria.

Could China’s journey of malaria elimination extend to Africa?

World Health Organization (WHO) certified China malaria-free on June 30, 2021, which brightens the goal of global malaria elimination efforts. China contributed its unique innovations to the global community: Artemisinin, discovered by Tu Youyou, has saved millions of lives globally;the “1-3-7” norm developed in 2012, has been adapted in the local contexts of countries in the Southeast Asia and Africa. How to the targets of Global Technical Strategy for Malaria (GTS) 2016−2030. By looking into the malaria control phase, towards elimination phase from 1960 to 2011 in sub-Saharan Africa and China, we found that the gap in malaria burden will widen unless the interventions in Africa are enhanced. It is imperative to identify the key China–Africa cooperation areas on malaria control and elimination, so that synergized efforts could be pooled together to help African countries achieve the elimination goal. The practices from China malaria control and elimination efforts could be leveraged to fast-track malaria elimination efforts in Africa, which makes it possible that the China’s journey of malaria elimination extends to Africa.

China-UK-Tanzania Pilot Project on Malaria Control

The China-UK-Tanzania Pilot Project on Malaria Control supported by the China-UK Global Health Support Programme and funded by the UK Department for International Development(DFID)is the first pilot project of its kind for the Chinese government in Africa.The encouraging results of this pilot project demonstrated that the malaria burden could be reduced by 81%(1)when China’s experience with malaria control was shared in Tanzania through interactions between health officials from China and Tanzania.

Approaching Malaria Elimination in China

Malaria has been one of the most important public health problems over China and world.When dated back to the mid-20th century,malaria seriously affected the health of Chinese people with widespread epidemics.About 30 million malaria cases with an estimated 1%mortality rate were recorded in China each year in the 1940s,which caused an extremely high disease burden and a toll on the labor force(1–2).Even as recently as the 1970s,a peak in the incidence of malaria was recorded with 24.1 million cases(1–2).

Development and Impacts of the Sierra Leone-China Laboratory for Parasitic Diseases Testing and Surveillance

BACKGROUND The Republic of Sierra Leone is located on the west coast of Africa,bordering Guinea and Liberia,with a population of 7.8 million in 2019(1).It has a tropical monsoon climate,with high temperatures and plentiful precipitation.As one of the least developed countries in the world(2),Sierra Leone has long struggled with poor health outcomes with a life expectancy at birth of 59 for male and 61 for female,and high maternal and neonatal mortality,threatened by infectious diseases such as malaria,tuberculosis,typhoid fever,cholera,and Lassa fever(3).

A direct,sensitive and high-throughput genus and species-specific molecular assay for large-scale malaria screening

Background:Infectious disease diagnostics often requires sensitive molecular assays that identify at both genus and species levels.For large scale screening,such as malaria screening for elimination,diagnostic assay can be a challenge,as both the throughput and cost of the assay must be considered.The requirement of nucleic acid extraction hampers the throughput of most molecular assays.Co-amplification of multiple species or multiplex identification either can result in missed diagnosis or are too costly for large-scale screening.A genus-and species-specific diagnostic assay with simplified procedure,high sensitivity and throughput is still needed.This study aimed to develop a sensitive and high-throughput approach for large-scale infectious disease screening.Methods:We developed multi-section Capture and Ligation Probe PCR(mCLIP-PCR)for the direct detection of RNA without extraction and reverse transcription.Multiple tailed sandwich hybridization probes were used to bind at genus-and species-specific sections of the target RNA to cooperatively capture the target onto a 96-well plate.After enzymatic ligation of the bound probes,a single-stranded DNA formed at each section with distinct tail sequence at the ends.They were separately PCR-amplified with primers corresponding to tail sequences for genus or species identification.We applied the method to the active screening ofPlasmodium infections of 4,580 asymptomatic dried blood spot samples collected in malaria endemic areas and compared the results with standard qPCR using linear regression.Results:With multi-section cooperative capture but separate amplification strategy,we accurately identified genusPlasmodium and speciesP.falciparum andP.vivax without RNA extraction,with favorable sensitivities among the published reports.In the active screening,our method identified all 53 positive infections including two mixed infections,and twoP.vivax infections that were missed by standard qPCR.Conclusions:mCLIP-PCR provides a sensitive and high-throughput approach to large-scale infectious disease screening with low cost and labor,making it a valuable tool for malaria elimination in endemic region.

Role of international network on surveillance and response system leading to malaria elimination: China’s engagement in global health

China has accumulated multiple practices and experiences in building and enhancing malaria surveillance and response system. As China’s engagement into global health has gathered stronger momentum than ever, China together with the Swiss Tropical and Public Health Institute and WHO has organised five sessions of the International Forum on Surveillance-Response System Leading to Tropical Diseases Elimination during 2012–2020, in which malaria elimination has always been one of the hottest topics. In this study, the roles of international network on the surveillance and response system were explored to achieve a global malaria-free goal. China’s approach to malaria elimination has demonstrated significance of global collaboration on taking joint prevention and control, and building a worldwide institutional-based network.

Evaluation of Malaria Standard Microscopy and Rapid Diagnostic Tests for Screening—Southern Tanzania,2018–2019

Summary What is already known about this topic?Microscopy is the gold standard for parasitological confirmation,but the accuracy of microscopic diagnosis is influenced by the skill of the technicians.An alternative is the immunologic-based malaria rapid diagnostic tests(mRDTs).What is added by this report?Our study evaluated standard microscopy in health system(SMHS)and mRDTs for focused screening and treatment of malaria(FSAT)in Southern Tanzania.We showed that mRDTs were more sensitive than local SMHS for diagnosing malaria infection.What are the implications for public health practices?Malaria rapid diagnostic tests can be useful as an alternative to SMHS for FSAT in the local context of Tanzania.

Challenges of Sustaining Malaria Community Case Management in 81 Township Hospitals along the China-Myanmar Border Region—Yunnan Province,China,2020

Summary What is already known on this topic?The health workforce at township hospitals in the China-Myanmar border region has played a key role in sustaining Community case management of malaria(CCMm),while few studies have investigated their performance and challenges.What is added by this report?Sustaining CCMm in the region was subject to the following major challenges.