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Sa-Ngamuang C, Lawpoolsri S, Su Yin M, Barkowsky T, Cui L, Prachumsri J, Haddawy P. Assessment of malaria risk in Southeast Asia: a systematic review. Malar J 2023; 22:339. [PMID: 37940923 PMCID: PMC10631000 DOI: 10.1186/s12936-023-04772-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 10/26/2023] [Indexed: 11/10/2023] Open
Abstract
BACKGROUND Several countries in Southeast Asia are nearing malaria elimination, yet eradication remains elusive. This is largely due to the challenge of focusing elimination efforts, an area where risk prediction can play an essential supporting role. Despite its importance, there is no standard numerical method to quantify the risk of malaria infection. Thus, there is a need for a consolidated view of existing definitions of risk and factors considered in assessing risk to analyse the merits of risk prediction models. This systematic review examines studies of the risk of malaria in Southeast Asia with regard to their suitability in addressing the challenges of malaria elimination in low transmission areas. METHODS A search of four electronic databases over 2010-2020 retrieved 1297 articles, of which 25 met the inclusion and exclusion criteria. In each study, examined factors included the definition of the risk and indicators of malaria transmission used, the environmental and climatic factors associated with the risk, the statistical models used, the spatial and temporal granularity, and how the relationship between environment, climate, and risk is quantified. RESULTS This review found variation in the definition of risk used, as well as the environmental and climatic factors in the reviewed articles. GLM was widely adopted as the analysis technique relating environmental and climatic factors to malaria risk. Most of the studies were carried out in either a cross-sectional design or case-control studies, and most utilized the odds ratio to report the relationship between exposure to risk and malaria prevalence. CONCLUSIONS Adopting a standardized definition of malaria risk would help in comparing and sharing results, as would a clear description of the definition and method of collection of the environmental and climatic variables used. Further issues that need to be more fully addressed include detection of asymptomatic cases and considerations of human mobility. Many of the findings of this study are applicable to other low-transmission settings and could serve as a guideline for further studies of malaria in other regions.
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Affiliation(s)
- Chaitawat Sa-Ngamuang
- Faculty of Information and Communication Technology, Mahidol University, Nakhon Pathom, Thailand
| | - Saranath Lawpoolsri
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Myat Su Yin
- Faculty of Information and Communication Technology, Mahidol University, Nakhon Pathom, Thailand
| | - Thomas Barkowsky
- Bremen Spatial Cognition Center (BSCC), University of Bremen, Bremen, Germany
| | - Liwang Cui
- Division of Infectious Diseases and International Medicine, Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, USA
| | - Jetsumon Prachumsri
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Peter Haddawy
- Faculty of Information and Communication Technology, Mahidol University, Nakhon Pathom, Thailand.
- Bremen Spatial Cognition Center (BSCC), University of Bremen, Bremen, Germany.
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Liang S, Guo R, Zhuang J, Li P, Chang Z, Zhu W, Jin Z. Analysis of epidemiological changes and elimination effects for malaria in Handan city, the north China. Medicine (Baltimore) 2022; 101:e31722. [PMID: 36550922 PMCID: PMC9771291 DOI: 10.1097/md.0000000000031722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The elimination of malaria requires high-quality surveillance data to quickly detect and respond to individual cases. This study aims to analyze the epidemiological characteristics of malaria and ascertain the long-term epidemic trends of malaria by 2020 in Handan China. Case-level data for the period 2011 to 2020 were extracted from Chinese Information System for Disease Control and Prevention. The lamp trap method was used to capture mosquitoes so that the characteristics of mosquitoes can be analyzed. The incidence, accuracy, and timeliness of malaria case diagnosis, reporting and investigation were evaluated at the elimination stage (2011-2020) in Handan City, China. Between 2011 and 2020, 94 malaria cases were reported in Handan City, of which 93 malaria cases were male and all of which were imported from abroad. The annual average incidence decreased from 622.33/100,000 to 0.11/100,000 in the elimination stage. Since the initiation of the National Malaria Elimination Program in 2010, malaria cases have been consistent with the increase in overseas export channels and labor personnel service. There is a need to strengthen malaria surveillance of returning workers from Africa and to conduct timely blood tests to diagnose and treat imported infections. Local authorities ensure that imported malaria cases can be timely diagnosed, reported, treated and investigated at local level.
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Affiliation(s)
- Shuang Liang
- School of Medicine, Hebei University of Engineering, Handan, China
- Handan Key Laboratory of Integrated Medical and Industrial Application in Basic Medicine, Handan, China
| | - Ruiling Guo
- Handan Municipal Centre for Disease Control and Prevention, Handan, China
| | - Jing Zhuang
- Handan Municipal Centre for Disease Control and Prevention, Handan, China
| | - Penghui Li
- School of Medicine, Hebei University of Engineering, Handan, China
- Handan Key Laboratory of Integrated Medical and Industrial Application in Basic Medicine, Handan, China
| | - Zhongzheng Chang
- School of Medicine, Hebei University of Engineering, Handan, China
- Handan Key Laboratory of Integrated Medical and Industrial Application in Basic Medicine, Handan, China
| | - Wangdong Zhu
- School of Medicine, Hebei University of Engineering, Handan, China
- Handan Key Laboratory of Integrated Medical and Industrial Application in Basic Medicine, Handan, China
| | - Zengjun Jin
- School of Medicine, Hebei University of Engineering, Handan, China
- Handan Key Laboratory of Integrated Medical and Industrial Application in Basic Medicine, Handan, China
- Handan Municipal Centre for Disease Control and Prevention, Handan, China
- * Correspondence: Zengjun Jin, School of Medicine, Hebei University of Engineering, Handan, Hebei 056038, China (e-mail: )
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Lin ZR, Yin SS, Yang J, Guo XR, Dong CL, Lin YK, Ding CL, Sun XD, Yan RX, Yang SL, Zhou XH, Xu JW. The public health response to an outbreak of border-spill malaria along China-Myanmar border. PLoS One 2022; 17:e0275932. [PMID: 36525438 PMCID: PMC9757579 DOI: 10.1371/journal.pone.0275932] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/27/2022] [Indexed: 12/23/2022] Open
Abstract
INTRODUCTION Malaria importation can be caused by cross-border movement either of both people and anopheline mosquitoes. However, there still lacks robust evidence of imported malaria caused by Plasmodium spp. infected anopheles along international border areas (border-spill malaria). The objectives of this study were to confirm whether an outbreak of Plasmodium vivax malaria is border-spill malaria and assess the effects of China's public health response along China-Myanmar border. METHODS Epidemiological, parasitological and entomological investigations were conducted to investigate the outbreak of border-spill malaria. Meanwhile, comprehensive interventions were carried out to prevent further transmission and reintroduction of malaria. RESULTS Rapid diagnostic testing, microscopy and polymerase chain reaction were performed and the infections were confirmed as P. vivax. A total of 22 (9.21%) of 239 workers contracted P. vivax during the outbreak. Multivariate logistic regression analysis identified that the distance of worker shelters in China within 300 meters to the internally displaced person (IDP) camps in Myanmar was a risk factors associated with malaria infection (adjusted odds ratio 7.5920; 95% confidence interval, 2.6079-22.1013; P = 0.0002). After comprehensive interventions, malaria transmission was successfully interpreted and prevented at the project site till the completion of project on 14 January 2020, and recurrence of P. vivax malaria was not detected by the end of 2020. CONCLUSION This study provided robust evidence of border-spill malaria along China-Myanmar border. Malaria parasite reservoir and distance travelled by female anopheline mosquitoes are two determinants for border-spill malaria. The public health response to the outbreak indicates that the malaria surveillance and response system works well in preventing reintroduction of malaria. However, prevention of border-spill malaria is still a major challenge in the Yunnan border area, China.
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Affiliation(s)
- Zu-Rui Lin
- Malaria Division, Yunnan Institute of Parasitic Diseases, Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Key Laboratory of Vector-borne Disease Control and Research, Yunnan Institute of Parasitic Diseases Innovative Team of Key Techniques for Vector Borne Disease Control and Prevention, Training Base of International Scientific Exchange and Education in Tropical Diseases for South and Southeast Asia, Pu’er, Yunnan, China
| | - Shan-Shan Yin
- Parasitic Disease Section, Yingjiang County Center for Disease Control and Prevention, Yingjiang, Yunnan, China
| | - Jie Yang
- Parasitic Disease Section, Donghong Prefecture Center for Disease Control and Prevention, Mangshi, Yunnan, China
| | - Xiang-Rui Guo
- Parasitic Disease Section, Yingjiang County Center for Disease Control and Prevention, Yingjiang, Yunnan, China
| | - Chao-Liang Dong
- Parasitic Disease Section, Donghong Prefecture Center for Disease Control and Prevention, Mangshi, Yunnan, China
| | - Ying-Kun Lin
- Parasitic Disease Section, Donghong Prefecture Center for Disease Control and Prevention, Mangshi, Yunnan, China
| | - Chun-Li Ding
- Malaria Division, Yunnan Institute of Parasitic Diseases, Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Key Laboratory of Vector-borne Disease Control and Research, Yunnan Institute of Parasitic Diseases Innovative Team of Key Techniques for Vector Borne Disease Control and Prevention, Training Base of International Scientific Exchange and Education in Tropical Diseases for South and Southeast Asia, Pu’er, Yunnan, China
| | - Xiao-Dong Sun
- Malaria Division, Yunnan Institute of Parasitic Diseases, Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Key Laboratory of Vector-borne Disease Control and Research, Yunnan Institute of Parasitic Diseases Innovative Team of Key Techniques for Vector Borne Disease Control and Prevention, Training Base of International Scientific Exchange and Education in Tropical Diseases for South and Southeast Asia, Pu’er, Yunnan, China
| | - Run-Xian Yan
- Parasitic Disease Section, Yingjiang County Center for Disease Control and Prevention, Yingjiang, Yunnan, China
| | - Suo-Lan Yang
- Parasitic Disease Section, Yingjiang County Center for Disease Control and Prevention, Yingjiang, Yunnan, China
| | - Xian-Hua Zhou
- Parasitic Disease Section, Yingjiang County Center for Disease Control and Prevention, Yingjiang, Yunnan, China
| | - Jian-Wei Xu
- Malaria Division, Yunnan Institute of Parasitic Diseases, Yunnan Provincial Centre of Malaria Research, Yunnan Provincial Key Laboratory of Vector-borne Disease Control and Research, Yunnan Institute of Parasitic Diseases Innovative Team of Key Techniques for Vector Borne Disease Control and Prevention, Training Base of International Scientific Exchange and Education in Tropical Diseases for South and Southeast Asia, Pu’er, Yunnan, China
- * E-mail:
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Huang F, Feng XY, Zhou SS, Tang LH, Xia ZG. Establishing and applying an adaptive strategy and approach to eliminating malaria: practice and lessons learnt from China from 2011 to 2020. Emerg Microbes Infect 2022; 11:314-325. [PMID: 34989665 PMCID: PMC8786258 DOI: 10.1080/22221751.2022.2026740] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/05/2022] [Indexed: 12/17/2022]
Abstract
ABSTRACTOn 30 June 2021, China was certified malaria-free by the World Health Organization. In this study, the evolution, performance, outcomes, and impact of China's adaptive strategy and approach for malaria elimination from 2011 to 2020 were analysed using 10-year data. The strategy and approach focused on timely detection and rapid responses to individual cases and foci. Indigenous cases declined from 1,308 in 2011 to 36 in 2015, and the last one was reported from Yunnan Province in April 2016, although thousands of imported cases still occur annually. The "1-3-7" approach was implemented successfully between 2013 and 2020, with 100% of cases reported within 24 h, 94.5% of cases investigated within three days of case reporting, and 93.4% of foci responses performed within seven days. Additionally, 81.6% of patients attended the first healthcare visit within 1-3 days of onset and 58.4% were diagnosed as malaria within three days of onset, in 2017-2020. The adaptive strategy and approach, along with their universal implementation, are most critical in malaria elimination. In addition to strengthening surveillance on drug resistance and vectors and border malaria collaboration, a further adapted three-step strategy and the corresponding "3-3-7" model are recommended to address the risks of re-transmission and death by imported cases after elimination. China's successful practice and lessons learnt through long-term efforts provide a reference for countries moving towards elimination.
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Affiliation(s)
- Fang Huang
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, National Institute of Parasitic Diseases, Shanghai, People’s Republic of China
| | - Xin-Yu Feng
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, National Institute of Parasitic Diseases, Shanghai, People’s Republic of China
| | - Shui-Sen Zhou
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, National Institute of Parasitic Diseases, Shanghai, People’s Republic of China
| | - Lin-Hua Tang
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, National Institute of Parasitic Diseases, Shanghai, People’s Republic of China
| | - Zhi-Gui Xia
- Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, National Institute of Parasitic Diseases, Shanghai, People’s Republic of China
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Feng X, Feng J, Zhang L, Tu H, Xia Z. Vector control in China, from malaria endemic to elimination and challenges ahead. Infect Dis Poverty 2022; 11:54. [PMID: 35562786 PMCID: PMC9102289 DOI: 10.1186/s40249-022-00971-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 04/09/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vector control is an important approach to preventing and controlling malaria. From the malaria epidemic to malaria elimination in China, vector control has played an essential and irreplaceable role in the historical process. This review systematically summarizes the evolution, adjustment, and optimization of vector control strategy towards elimination and discusses the challenges ahead. MAIN TEXT This review first summarizes the evolution of vector control strategies during different stages of malaria epidemic, control, elimination, and post-elimination in China. We then distill the vector control experience and lessons in different stages. We discuss the current and future challenges and propose future research directions and developments for novel malaria vector control strategies. RESULTS Vector control has played an invaluable role in achieving malaria elimination. China adopted different prevention and control measures in response to the different malaria-endemic situations and vector distributions. Firstly, baseline surveys were initiated to establish the entomological data and helped clarify the prevention priorities and targets. Secondly, targeted and adjusted vector control strategies were conducted in various regions according to the local epidemic characteristics and different vector species. Thirdly, scientific research facilitated efficient vector-control strategies. In addition, the overall economic and social development have promoted environmental improvement, personal protection, and health care. Prediction of the vector distribution was integrated into risk assessment strategies, allowing for sustaining achievements in risk areas. CONCLUSIONS The tailored and adapted vector control strategies have played a critical role in China's malaria prevention, control, and elimination. Achievements and lessons learned on vector control from this progress would provide a practical reference in coping with the challenges and potential barriers other countries face in the global effort to eliminate malaria.
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Affiliation(s)
- Xinyu Feng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 200025, China
| | - Jun Feng
- Shanghai Municipal Center for Disease Control and Prevention, Shanghai, 200336, China
| | - Li Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 200025, China
| | - Hong Tu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 200025, China
| | - Zhigui Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, National Center for International Research On Tropical Diseases, Shanghai, 200025, China.
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Akoniyon OP, Adewumi TS, Maharaj L, Oyegoke OO, Roux A, Adeleke MA, Maharaj R, Okpeku M. Whole Genome Sequencing Contributions and Challenges in Disease Reduction Focused on Malaria. BIOLOGY 2022; 11:587. [PMID: 35453786 PMCID: PMC9027812 DOI: 10.3390/biology11040587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 12/11/2022]
Abstract
Malaria elimination remains an important goal that requires the adoption of sophisticated science and management strategies in the era of the COVID-19 pandemic. The advent of next generation sequencing (NGS) is making whole genome sequencing (WGS) a standard today in the field of life sciences, as PCR genotyping and targeted sequencing provide insufficient information compared to the whole genome. Thus, adapting WGS approaches to malaria parasites is pertinent to studying the epidemiology of the disease, as different regions are at different phases in their malaria elimination agenda. Therefore, this review highlights the applications of WGS in disease management, challenges of WGS in controlling malaria parasites, and in furtherance, provides the roles of WGS in pursuit of malaria reduction and elimination. WGS has invaluable impacts in malaria research and has helped countries to reach elimination phase rapidly by providing required information needed to thwart transmission, pathology, and drug resistance. However, to eliminate malaria in sub-Saharan Africa (SSA), with high malaria transmission, we recommend that WGS machines should be readily available and affordable in the region.
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Affiliation(s)
- Olusegun Philip Akoniyon
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Taiye Samson Adewumi
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Leah Maharaj
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Olukunle Olugbenle Oyegoke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Alexandra Roux
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Matthew A. Adeleke
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
| | - Rajendra Maharaj
- Office of Malaria Research, South African Medical Research Council, Cape Town 7505, South Africa;
| | - Moses Okpeku
- Discipline of Genetics, School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4041, South Africa; (O.P.A.); (T.S.A.); (L.M.); (O.O.O.); (A.R.); (M.A.A.)
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Tu H, Feng J, Yu C, Lin K, Peiyu W, Shaomi X, Lingyun L, Jian L. Asymptomatic malaria infection at the China-Vietnam border: Knowledge and implications for the cross-border migrant population during the COVID-19 pandemic. Travel Med Infect Dis 2022; 47:102307. [PMID: 35276354 PMCID: PMC8902057 DOI: 10.1016/j.tmaid.2022.102307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 11/28/2022]
Abstract
Background Eliminating malaria along the China-Vietnam border remains one of the greatest challenges in China, especially during the coronavirus disease 2019 (COVID-19) pandemic, which has disrupted the continuity of malaria control and elimination programs. Understanding the factors associated with asymptomatic malaria infection will inform control interventions aimed at elimination of the disease among migrants from Vietnam working in China, who constitute an at-risk population. Methods From March 2018 to September 2019, 108 migrants from Vietnam working in Ningming County, Guangxi, were enrolled in this study. Each person was interviewed using a structured questionnaire. Blood samples were collected and sent for PCR detection and sequencing. The obtained sequences were analyzed using the BLAST program and DNAMAN software. Results The proportion of participants with malaria knowledge was low, with 19.4% (21/108) reporting knowledge about transmission, 23.2% (25/108) reporting knowledge about clinical symptoms, 7.4% (8/108) reporting awareness of the risk of death and 14.8% (16/108) reporting awareness of prevention methods. No significant difference in the malaria knowledge rate was found among occupational groups, except in the migrant worker group, whose knowledge rate was higher than those in the other occupational groups (χ2 = 32.452, p < 0.001). Although most of the participants (80.6%, 87/108) owned mosquito nets, only approximately half of the participants (49.1%, 53/108) reported using bed nets. The parasitological analysis revealed that 5.6% (6/108) of all the participants were positive for malaria, including 5 participants with Plasmodium falciparum and 1 participant with Plasmodium vivax malaria. There were no statistically significant differences in the positivity rates among the different age, sex, family-size, nationality, occupational, and behavior groups. The positivity rates in individuals who did not use mosquito nets, did not use mosquito coils, and did not install mosquito nets were 4.8% (1/21), 6.8% (3/44), and 3.6% (2/55), respectively. Conclusion Health education focused on high-risk populations, such as migrant workers and forest goers, should be strengthened. Verbal communication and information transmission via the internet, radio, and mobile phone platforms may be required during the COVID-19 pandemic. Further risk assessments and proactive case detection should also be performed in Ningming County and other border counties in Guangxi to detect active and asymptomatic infections in a timely manner and prevent re-establishment of the disease in these communities.
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Affiliation(s)
- Hong Tu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, National Health Commission Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, Shanghai, PR China
| | - Jun Feng
- Shanghai Municipal Center for Diseases Control and Prevention, Shanghai, PR China.
| | - Chenghang Yu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, National Health Commission Key Laboratory of Parasite and Vector Biology, WHO Collaborating Centre for Tropical Diseases, Shanghai, PR China
| | - Kangming Lin
- Institute of Parasitic Diseases, Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Guangxi, PR China
| | - Wang Peiyu
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
| | - Xiang Shaomi
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
| | - Luo Lingyun
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
| | - Li Jian
- Ningming County Center for Diseases Control and Prevention, Ningming, Guangxi, PR China
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8
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Cui YB, Shen HM, Chen SB, Kassegne K, Shi TQ, Xu B, Chen JH, Wu JH, Wang Y. Genetic Diversity and Selection of Plasmodium vivax Apical Membrane Antigen-1 in China-Myanmar Border of Yunnan Province, China, 2009-2016. Front Cell Infect Microbiol 2022; 11:742189. [PMID: 35071030 PMCID: PMC8766981 DOI: 10.3389/fcimb.2021.742189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/09/2021] [Indexed: 11/26/2022] Open
Abstract
Plasmodium vivax apical membrane antigen-1 (PvAMA-1) is an important vaccine candidate for vivax malaria. However, antigenic variation within PvAMA-1 is a major obstacle to the design of a global protective malaria vaccine. In this study, we analyzed the genetic polymorphism and selection of the PvAMA-1 gene from 152 P. vivax isolates from imported cases to China, collected in the China–Myanmar border (CMB) area in Yunnan Province (YP) during 2009–2011 (n = 71) and 2014–2016 (n = 81), in comparison with PvAMA-1 gene information from Myanmar (n = 73), collected from public data. The overall nucleotide diversity of the PvAMA-1 gene from the 152 YP isolates was 0.007 with 76 haplotypes identified (Hd = 0.958). Results from the population structure suggested three groups among the YP and Myanmar isolates with optimized clusters value of K = 7. In addition, YP (2014–2016) isolates generally lacked some K components that were commonly found in YP (2009–2011) and Myanmar. Meanwhile, PvAMA-1 domain I is found to be the dominant target of positive diversifying selection and most mutation loci were found in this domain. The mutation frequencies of D107N/A, R112K/T, K120R, E145A, E277K, and R438H in PvAMA-1 were more than 70% in the YP isolates. In conclusion, high genetic diversity and positive selection were found in the PvAMA-1 gene from YP isolates, which are significant findings for the design and development of PvAMA-1-based malaria vaccine.
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Affiliation(s)
- Yan-Bing Cui
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Hai-Mo Shen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Shen-Bo Chen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Kokouvi Kassegne
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tian-Qi Shi
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Bin Xu
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, China.,National Health Commission of the People's Republic of China (NHC) Key Laboratory of Parasite and Vector Biology, Shanghai, China.,World Health Organization (WHO) Collaborating Center for Tropical Diseases, Shanghai, China.,National Center for International Research on Tropical Diseases, Shanghai, China.,School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Hong Wu
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, China.,Department of Parasitology, Provincial Key Laboratory of Modern Pathogen Biology, Guizhou Medical University, Guiyang, China
| | - Yue Wang
- Institute of Parasitic Diseases, School of Basic Medical Sciences and Forensic Medicine, Hangzhou Medical College, Hangzhou, China
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9
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A retrospective analysis of malaria epidemiological characteristics in Yingjiang County on the China-Myanmar border. Sci Rep 2021; 11:14129. [PMID: 34239003 PMCID: PMC8266812 DOI: 10.1038/s41598-021-93734-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/15/2021] [Indexed: 11/08/2022] Open
Abstract
Yingjiang County, which is on the China–Myanmar border, is the main focus for malaria elimination in China. The epidemiological characteristics of malaria in Yingjiang County were analysed in a retrospective analysis. A total of 895 malaria cases were reported in Yingjiang County between 2013 and 2019. The majority of cases occurred in males (70.7%) and individuals aged 19–59 years (77.3%). Plasmodium vivax was the predominant species (96.6%). The number of indigenous cases decreased gradually and since 2017, no indigenous cases have been reported. Malaria cases were mainly distributed in the southern and southwestern areas of the county; 55.6% of the indigenous cases were reported in Nabang Township, which also had the highest risk of imported malaria. The “1–3–7” approach has been implemented effectively, with 100% of cases reported within 24 h, 88.9% cases investigated and confirmed within 3 days and 98.5% of foci responded to within 7 days. Although malaria elimination has been achieved in Yingjiang County, sustaining elimination and preventing the re-establishment of malaria require the continued strengthening of case detection, surveillance and response systems targeting the migrant population in border areas.
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10
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Fang Y, Li XS, Zhang W, Xue JB, Wang JZ, Yin SQ, Li SG, Li XH, Zhang Y. Molecular epidemiology of mosquito-borne viruses at the China-Myanmar border: discovery of a potential epidemic focus of Japanese encephalitis. Infect Dis Poverty 2021; 10:57. [PMID: 33902684 PMCID: PMC8073957 DOI: 10.1186/s40249-021-00838-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/08/2021] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Mosquito-based arbovirus surveillance can serve as an early warning in evaluating the status of mosquito-borne virus prevalence and thus prevent local outbreaks. Although Tengchong County in Yunnan Province-which borders Myanmar-is abundant and diverse in mosquitoes, very few mosquito-based arbovirus investigations have been conducted in the recent decade. Herein, this study aims to evaluate the presence and the diffusion of mosquito-borne pathogens, currently prevalent in this region. METHODS We collected 9486 mosquitoes, representing eight species, with Culex tritaeniorhynchus and Anopheles sinensis as the dominant species, during high mosquito activity seasons (July-October) in Tengchong, in 2018. Samples collected from 342 pools were tested using reverse-transcription PCR to determine the species, distribution, and infection rates of virus and parasite, and further analyze their genotypes, phylogenetic relationships, infection rate, and potential pathogenicity. RESULTS Fifteen Japanese encephalitis virus (JEV) strains from Cx. tritaeniorhynchus pools were detected. Seven strains of insect-specific flaviviruses (ISFVs), including two Aedes flavivirus (AeFV) and Yunnan Culex flavivirus strains each, one Culex theileri flavivirus, Yamadai flavivirus (YDFV) and Anopheles-associated flavivirus (AAFV) strains each were detected in Aedes albopictus, Cx. tritaeniorhynchus, Cx. vagans, Cx. pseudovihnui, and An. sinensis pools, respectively. The whole-genome was successfully amplified in one strain of JEV and AeFV each. Phylogenetic analysis using the E gene placed all the newly detected JEV strains into the GI-b genotype. They showed highly nucleotide identities, and were most closely related to the strain detected in Tengchong in 2010. The comparison of the E protein of JEV strains and vaccine-derived strain, showed six amino residue differences. The bias-corrected maximum likelihood estimation values (and 95% confidence interval) for JEV in Cx. tritaeniorhynchus collected in Tengchong in 2018 were 2.4 (1.4-3.9). CONCLUSIONS A potential Japanese encephalitis epidemic focus with the abundance of host mosquitoes and high JEV infection rate was observed in Tengchong. In addition, at least five species of ISFVs co-circulate in this area. This study highlights the importance of widespread and sustained mosquito-based arbovirus surveillance in local areas to prevent the transmission of JEV, and other emerging/re-emerging mosquito-borne pathogens.
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Affiliation(s)
- Yuan Fang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); NHC Key Laboratory of Parasite and Vector Biology; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xi-Shang Li
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Wei Zhang
- Zichuan District Center for Disease Control and Prevention, Shandong, Zibo, China
| | - Jing-Bo Xue
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); NHC Key Laboratory of Parasite and Vector Biology; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Zhi Wang
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Shou-Qin Yin
- Zichuan District Center for Disease Control and Prevention, Shandong, Zibo, China
| | - Sheng-Guo Li
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Xin-He Li
- Tengchong County Center for Disease Control and Prevention, Tengchong, Yunnan, China
| | - Yi Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); NHC Key Laboratory of Parasite and Vector Biology; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Shanghai, China.
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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11
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Vantaux A, Riehle MM, Piv E, Farley EJ, Chy S, Kim S, Corbett AG, Fehrman RL, Pepey A, Eiglmeier K, Lek D, Siv S, Mueller I, Vernick KD, Witkowski B. Anopheles ecology, genetics and malaria transmission in northern Cambodia. Sci Rep 2021; 11:6458. [PMID: 33742030 PMCID: PMC7979810 DOI: 10.1038/s41598-021-85628-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/04/2021] [Indexed: 12/20/2022] Open
Abstract
In the Greater Mekong Subregion, malaria cases have significantly decreased but little is known about the vectors or mechanisms responsible for residual malaria transmission. We analysed a total of 3920 Anopheles mosquitoes collected during the rainy and dry seasons from four ecological settings in Cambodia (villages, forested areas near villages, rubber tree plantations and forest sites). Using odor-baited traps, 81% of the total samples across all sites were collected in cow baited traps, although 67% of the samples attracted by human baited traps were collected in forest sites. Overall, 20% of collected Anopheles were active during the day, with increased day biting during the dry season. 3131 samples were identified morphologically as 14 different species, and a subset was also identified by DNA amplicon sequencing allowing determination of 29 Anopheles species. The investigation of well characterized insecticide mutations (ace-1, kdr, and rdl genes) indicated that individuals carried mutations associated with response to all the different classes of insecticides. There also appeared to be a non-random association between mosquito species and insecticide resistance with Anopheles peditaeniatus exhibiting nearly fixed mutations. Molecular screening for Plasmodium sp. presence indicated that 3.6% of collected Anopheles were positive, most for P. vivax followed by P. falciparum. These results highlight some of the key mechanisms driving residual human malaria transmission in Cambodia, and illustrate the importance of diverse collection methods, sites and seasons to avoid bias and better characterize Anopheles mosquito ecology in Southeast Asia.
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Affiliation(s)
- Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
| | - Michelle M Riehle
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Eakpor Piv
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Elise J Farley
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Sophy Chy
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Saorin Kim
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Anneli G Corbett
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Rachel L Fehrman
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Anais Pepey
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Karin Eiglmeier
- Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,CNRS Unit of Evolutionary Genomics, Modeling, and Health (UMR2000), Institut Pasteur, Paris, France
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control Program, Phnom Penh, Cambodia.,School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Sovannaroth Siv
- National Center for Parasitology, Entomology and Malaria Control Program, Phnom Penh, Cambodia
| | - Ivo Mueller
- Malaria: Parasites and Hosts Unit, Institut Pasteur, Paris, France
| | - Kenneth D Vernick
- Unit of Insect Vector Genetics and Genomics, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France.,CNRS Unit of Evolutionary Genomics, Modeling, and Health (UMR2000), Institut Pasteur, Paris, France
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
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12
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Zheng J, Shi B, Xia S, Yang G, Zhou XN. Spatial patterns of <em>Plasmodium vivax</em> transmission explored by multivariate auto-regressive state-space modelling - A case study in Baoshan Prefecture in southern China. GEOSPATIAL HEALTH 2021; 16. [PMID: 33733649 DOI: 10.4081/gh.2021.879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/21/2020] [Indexed: 06/12/2023]
Abstract
The transition from the control phase to elimination of malaria in China through the national malaria elimination programme has focussed attention on the need for improvement of the surveillance- response systems. It is now understood that routine passive surveillance is inadequate in the parasite elimination phase that requires supplementation by active surveillance in foci where cluster cases have occurred. This study aims to explore the spatial clusters and temporal trends of malaria cases by the multivariate auto-regressive state-space model (MARSS) along the border to Myanmar in southern China. Data for indigenous cases spanning the period from 2007 to 2010 were extracted from the China's Infectious Diseases Information Reporting Management System (IDIRMS). The best MARSS model indicated that malaria transmission in the study area during 36 months could be grouped into three clusters. The estimation of malaria transmission patterns showed a downward trend across all clusters. The proposed methodology used in this study offers a simple and rapid, yet effective way to categorize patterns of foci which provide assistance for active monitoring of malaria in the elimination phase.
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Affiliation(s)
- Jinxin Zheng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China; Key Laboratory of Parasite and Vector Biology, National Health Commission, Shanghai, China; National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai, China; Chinese Center for Tropical Diseases Research, Shanghai.
| | - Benyun Shi
- School of Computer Science and Technology, Nanjing Tech University, Nanjing, Jiangsu.
| | - Shang Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China; Key Laboratory of Parasite and Vector Biology, National Health Commission, Shanghai, China; National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai, China; Chinese Center for Tropical Diseases Research, Shanghai.
| | - Guojing Yang
- Hainan Medical University, Laboratory of Tropical Environment and Health, Haikou, Hainan, China; Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute; University of Basel, Basel.
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China; Key Laboratory of Parasite and Vector Biology, National Health Commission, Shanghai, China; National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai, China; Chinese Center for Tropical Diseases Research, Shanghai.
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13
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Wang X, Ruan W, Zhou S, Feng X, Yan H, Huang F. Prevalence of molecular markers associated with drug resistance of Plasmodium vivax isolates in Western Yunnan Province, China. BMC Infect Dis 2020; 20:307. [PMID: 32334523 PMCID: PMC7183581 DOI: 10.1186/s12879-020-05032-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/15/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Plasmodium vivax is the most widely distributed malaria parasite, and its drug resistance poses unique challenges to malaria elimination. The Greater Mekong Subregion (GMS) is known as the global epicenter of multidrug resistance. Surveillance of molecular markers associated with drug resistance in this area will help to inform drug policy. METHODS Dry blood spots from 58 patients out of 109 with P. vivax infection between 2017, December and 2019, March were obtained from Yingjiang County, Yunnan Province, along the China-Myanmar border. Pvdhfr, Pvdhps, Pvmdr1 and Pvcrt-o were amplified and sequenced to assess gene mutations. The polymorphism and prevalence of these molecular markers were analyzed. RESULTS Mutations in Pvdhfr at codons 57, 58, 61, 99 and 117 were detected in 27.59, 48.28, 27.59, 32.76 and 48.28% of the isolates, respectively. Single mutant haplotype (I13F57S58T61S99S117I173) was the most frequent (29.31%, 17/58), followed by double mutant haplotype (20.69%, 12/58). Of three types of tandem repeat variations of Pvdhfr, deletion type was the most common. Pvdhps showed a lower prevalence among mutation genotypes. Single mutant was dominant and accounted for 34.48% (20/58). Prevalence of Pvmdr1 mutations at codons 958 and 1076 were 100.00% and 84.48%, respectively. The proportion of double and single mutant types was 84.48% (49/58) and 15.52% (9/58), respectively. Eleven samples (18.97%, 11/58) showed K10 "AAG" insertion in chloroquine resistance transporter gene Pvcrt-o. CONCLUSIONS There was moderate diversity of molecular patterns of resistance markers of Pvdhfr, Pvdhps, Pvmdr1 and Pvcrt-o in imported P. vivax cases to Yingjiang county in Western Yunnan, along the China-Myanmar border. Prevalence and molecular pattern of candidate drug resistance markers Pvdhfr, Pvdhps, Pvmdr1 and Pvcrt-o were demonstrated in this current study, which would help to update drug policy.
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Affiliation(s)
- Xiaoxiao Wang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology, MOH, and WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People’s Republic of China
- Zhejiang Provincial Center for Disease Control and Prevention, Zhejiang, People’s Republic of China
| | - Wei Ruan
- Zhejiang Provincial Center for Disease Control and Prevention, Zhejiang, People’s Republic of China
| | - Shuisen Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology, MOH, and WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People’s Republic of China
| | - Xinyu Feng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology, MOH, and WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People’s Republic of China
| | - He Yan
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology, MOH, and WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People’s Republic of China
| | - Fang Huang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Key Laboratory of Parasite and Vector Biology, MOH, and WHO Collaborating Centre for Malaria, Schistosomiasis and Filariasis, Shanghai, People’s Republic of China
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14
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Routledge I, Lai S, Battle KE, Ghani AC, Gomez-Rodriguez M, Gustafson KB, Mishra S, Unwin J, Proctor JL, Tatem AJ, Li Z, Bhatt S. Tracking progress towards malaria elimination in China: Individual-level estimates of transmission and its spatiotemporal variation using a diffusion network approach. PLoS Comput Biol 2020; 16:e1007707. [PMID: 32203520 PMCID: PMC7117777 DOI: 10.1371/journal.pcbi.1007707] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/02/2020] [Accepted: 02/03/2020] [Indexed: 01/02/2023] Open
Abstract
In order to monitor progress towards malaria elimination, it is crucial to be able to measure changes in spatio-temporal transmission. However, common metrics of malaria transmission such as parasite prevalence are under powered in elimination contexts. China has achieved major reductions in malaria incidence and is on track to eliminate, having reporting zero locally-acquired malaria cases in 2017 and 2018. Understanding the spatio-temporal pattern underlying this decline, especially the relationship between locally-acquired and imported cases, can inform efforts to maintain elimination and prevent re-emergence. This is particularly pertinent in Yunnan province, where the potential for local transmission is highest. Using a geo-located individual-level dataset of cases recorded in Yunnan province between 2011 and 2016, we introduce a novel Bayesian framework to model a latent diffusion process and estimate the joint likelihood of transmission between cases and the number of cases with unobserved sources of infection. This is used to estimate the case reproduction number, Rc. We use these estimates within spatio-temporal geostatistical models to map how transmission varied over time and space, estimate the timeline to elimination and the risk of resurgence. We estimate the mean Rc between 2011 and 2016 to be 0.171 (95% CI = 0.165, 0.178) for P. vivax cases and 0.089 (95% CI = 0.076, 0.103) for P. falciparum cases. From 2014 onwards, no cases were estimated to have a Rc value above one. An unobserved source of infection was estimated to be moderately likely (p>0.5) for 19/ 611 cases and high (p>0.8) for 2 cases, suggesting very high levels of case ascertainment. Our estimates suggest that, maintaining current intervention efforts, Yunnan is unlikely to experience sustained local transmission up to 2020. However, even with a mean of 0.005 projected up to 2020, locally-acquired cases are possible due to high levels of importation.
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Affiliation(s)
| | - Shengjie Lai
- University of Southampton, Southampton, United Kingdom
| | | | | | | | - Kyle B. Gustafson
- Institute for Disease Modelling, Bellevue, Washington, United States of America
| | | | | | - Joshua L. Proctor
- Institute for Disease Modelling, Bellevue, Washington, United States of America
| | | | - Zhongjie Li
- Chinese Centers for Disease Control and Prevention, Beijing, China
| | - Samir Bhatt
- Imperial College London, London, United Kingom
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