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Survey of asymptomatic malaria and mosquito vectors in Muang Khua District of Phongsaly Province, China-Laos Border. Int J Infect Dis 2020; 96:141-147. [PMID: 32251803 DOI: 10.1016/j.ijid.2020.03.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/22/2020] [Accepted: 03/25/2020] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVES The China-Laos border has been identified as an important origin of imported malaria outside China. The aim of this study was to describe the asymptomatic malaria infections and epidemic trend of malaria in the China-Laos border region. METHODS A prevalence survey and surveillance of mosquito vectors was conducted in Muang Khua District of Phongsaly Province, China-Laos border, to determine the parasite carriage rate using nested PCR and microscopy. The species composition of malaria vectors was determined by overnight trapping. Blood samples were collected from 354 local residents aged 1-72 years in Sankang village in 2016. A total of 2430 adult mosquitoes were collected from four other villages in Muang Khua District from June to August 2016. RESULTS The parasite carriage rate was 7.63% (27/354) by microscopy or 7.91% (28/354) by nested PCR. The results of surveillance of the mosquito vectors revealed that the predominant genera of adult mosquitoes were Culex (69.92%, 1699/2430) and Anopheles (21.48%, 522/2430). Anopheles sinensis (82.95%, 433/522) was identified as the predominant species among the seven members of Anopheles found in this border region. CONCLUSIONS A high prevalence of asymptomatic malaria was present and the most important malaria vector was Anopheles sinensis, suggesting that the malaria epidemic situation on the China-Laos border is serious.
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Pang SC, Andolina C, Malleret B, Christensen PR, Lam-Phua SG, Razak MABA, Chong CS, Li D, Chu CS, Russell B, Rénia L, Ng LC, Nosten F. Singapore's Anopheles sinensis Form A is susceptible to Plasmodium vivax isolates from the western Thailand-Myanmar border. Malar J 2017; 16:465. [PMID: 29145859 PMCID: PMC5689142 DOI: 10.1186/s12936-017-2114-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 11/08/2017] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Singapore has been certified malaria-free by the World Health Organization since November 1982. However, sporadic autochthonous malaria outbreaks do occur. In one of the most recent outbreaks of vivax malaria, an entomological investigation identified Anopheles sinensis as the most probable vector. As metaphase karyotype studies divided An. sinensis into two forms, A and B, with different vector competence: the investigation of vector competence of An. sinensis found in Singapore was thus pursued using Plasmodium vivax field isolates from the Thailand-Myanmar border. METHODS Adults and larvae An. sinensis were collected from Singapore from 14 different locations, using various trapping and collection methods between September 2013 and January 2016. Molecular identification of An. sinensis species were conducted by amplifying the ITS2 and CO1 region using PCR. Experimental infections of An. sinensis using blood from seven patients infected with P. vivax from the Thailand-Myanmar border were conducted with Anopheles cracens (An. dirus B) as control. RESULTS Phylogenetic analysis showed that An. sinensis (F22, F2 and collected from outbreak areas) found in Singapore was entirely Form A, and closely related to An. sinensis Form A from Thailand. Artificial infection of these Singapore strain An. sinensis Form A resulted in the development of oocysts in four experiments, with the number of sporozoites produced by one An. sinensis ranging from 4301 to 14,538. CONCLUSIONS Infection experiments showed that An. sinensis Form A from Singapore was susceptible to Thai-Myanmar P. vivax strain, suggesting a potential role as a malaria vector in Singapore.
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Affiliation(s)
- Sook-Cheng Pang
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, Singapore, 138667 Singapore
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543 Singapore
| | - Chiara Andolina
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford, Old Road Campus, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Benoit Malleret
- Singapore Immunology Network (SIgN), A*STAR, 8A Biomedical Grove, Singapore, 138648 Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, 5 Science Drive 2, Blk MD4, Level 3, Singapore, 117597 Singapore
| | - Peter R. Christensen
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Sai-Gek Lam-Phua
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, Singapore, 138667 Singapore
| | | | - Chee-Seng Chong
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, Singapore, 138667 Singapore
| | - Daiqin Li
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543 Singapore
| | - Cindy S. Chu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, 720 Cumberland St, Dunedin, 9016 New Zealand
| | - Laurent Rénia
- Singapore Immunology Network (SIgN), A*STAR, 8A Biomedical Grove, Singapore, 138648 Singapore
| | - Lee-Ching Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, Singapore, 138667 Singapore
| | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford, Old Road Campus, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
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Ubalee R, Kim HC, Schuster AL, McCardle PW, Phasomkusolsil S, Takhampunya R, Davidson SA, Lee WJ, Klein TA. Vector Competence of Anopheles kleini and Anopheles sinensis (Diptera: Culicidae) From the Republic of Korea to Vivax Malaria-Infected Blood From Patients From Thailand. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:1425-1432. [PMID: 27493248 DOI: 10.1093/jme/tjw109] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/03/2016] [Indexed: 06/06/2023]
Abstract
In total, 1,300 each of Anopheles kleini Rueda and Anopheles sinensis Wiedemann sensu stricto (s.s.) females (colonized from the Republic of Korea) and Anopheles dirus Peyton & Harrison (Thai strain) were allowed to feed on blood from Thai malaria patients naturally infected with Plasmodium vivax The overall oocyst infection rates for An. dirus, An. kleini, and An. sinensis s.s. were 77.4, 46.1, and 45.9%, respectively. The mean number of oocysts was significantly higher for An. dirus (82.7) compared with An. kleini (6.1) and An. sinensis s.s. (8.6), whereas the mean number of oocysts for An. kleini and An. sinensis s.s. was similar. The overall sporozoite infection rates for An. dirus, An. kleini, and An. sinensis s.s. dissected on days 14-15, 21, and 28 days post-feed were significantly higher for An. dirus (90.0%) than An. kleini (5.4%), whereas An. kleini sporozoite rates were significantly higher than An. sinensis s.s. (<0.1%). The overall sporozoite indices for positive females with +3 (100-1,000 sporozoites) and +4 (>1,000 sporozoites) salivary gland indices were significantly higher for An. dirus (85.7%), compared with An. kleini (47.1%). Only one An. sinensis s.s. had sporozoites (+2; >10-100 sporozoites). These results indicate that An. kleini is a competent vector of vivax malaria. Although An. sinensis s.s. develops relatively high numbers of oocysts, it is considered a very poor vector of vivax malaria due to a salivary gland barrier.
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Affiliation(s)
- Ratawan Ubalee
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi, Phayathai, Bangkok 10400, Thailand (; ; ; , ; )
| | - Heung-Chul Kim
- 5th Medical Detachment, 168th Multifunctional Medical Battalion, 65th Medical Brigade, Unit 15247 APO AP 96205-5247
| | - Anthony L Schuster
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi, Phayathai, Bangkok 10400, Thailand (; ; ; , ; )
- Current Address: Preventive Health Services Office, Fort Sam Houston, TX, 78234
| | - Patrick W McCardle
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi, Phayathai, Bangkok 10400, Thailand (; ; ; , ; )
- Current Address: Walter Reed Army Institute of Research, Forest Glen, MD, 20910
| | - Siriporn Phasomkusolsil
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi, Phayathai, Bangkok 10400, Thailand (; ; ; , ; )
| | - Ratree Takhampunya
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi, Phayathai, Bangkok 10400, Thailand (; ; ; , ; )
| | - Silas A Davidson
- Department of Entomology, US Army Medical Component, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi, Phayathai, Bangkok 10400, Thailand (; ; ; , ; )
| | - Won-Ja Lee
- Korea National Institute of Health, Cheongju-Si, Chungbuk Province, 28159, Republic of Korea
| | - Terry A Klein
- Medical Department Activity-Korea (MEDDAC-K)/65th Medical Brigade, Unit 15281, Box 754, AP, 96205
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Rumisha SF, Smith T, Abdulla S, Masanja H, Vounatsou P. Modelling heterogeneity in malaria transmission using large sparse spatio-temporal entomological data. Glob Health Action 2014; 7:22682. [PMID: 24964782 PMCID: PMC4071307 DOI: 10.3402/gha.v7.22682] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 05/02/2014] [Accepted: 05/10/2014] [Indexed: 11/14/2022] Open
Abstract
Background Malaria transmission is measured using entomological inoculation rate (EIR), number of infective mosquito bites/person/unit time. Understanding heterogeneity of malaria transmission has been difficult due to a lack of appropriate data. A comprehensive entomological database compiled by the Malaria Transmission Intensity and Mortality Burden across Africa (MTIMBA) project (2001–2004) at several sites is the most suitable dataset for studying malaria transmission–mortality relations. The data are sparse and large, with small-scale spatial–temporal variation. Objective This work demonstrates a rigorous approach for analysing large and highly variable entomological data for the study of malaria transmission heterogeneity, measured by EIR, within the Rufiji Demographic Surveillance System (DSS), MTIMBA project site in Tanzania. Design Bayesian geostatistical binomial and negative binomial models with zero inflation were fitted for sporozoite rates (SRs) and mosquito density, respectively. The spatial process was approximated from a subset of locations. The models were adjusted for environmental effects, seasonality and temporal correlations and assessed based on their predictive ability. EIR was calculated using model-based predictions of SR and density. Results Malaria transmission was mostly influenced by rain and temperature, which significantly reduces the probability of observing zero mosquitoes. High transmission was observed at the onset of heavy rains. Transmission intensity reduced significantly during Year 2 and 3, contrary to the Year 1, pronouncing high seasonality and spatial variability. The southern part of the DSS showed high transmission throughout the years. A spatial shift of transmission intensity was observed where an increase in households with very low transmission intensity and significant reduction of locations with high transmission were observed over time. Over 68 and 85% of the locations selected for validation for SR and density, respectively, were correctly predicted within 95% credible interval indicating good performance of the models. Conclusion Methodology introduced here has the potential for efficient assessment of the contribution of malaria transmission in mortality and monitoring performance of control and intervention strategies.
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Affiliation(s)
- Susan Fred Rumisha
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; Department Biozentrum, University of Basel, Basel, Switzerland; Department of Disease Surveillance and Geographical Information Systems, National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Thomas Smith
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; Department Biozentrum, University of Basel, Basel, Switzerland
| | | | | | - Penelope Vounatsou
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; Department Biozentrum, University of Basel, Basel, Switzerland;
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Evaluation of the efficacy of chloroquine chemoprophylaxis for vivax malaria among Republic of Korea military personnel. Parasitol Int 2013; 62:494-6. [PMID: 23850837 DOI: 10.1016/j.parint.2013.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/22/2013] [Accepted: 07/03/2013] [Indexed: 11/21/2022]
Abstract
Chloroquine has been used massively for vivax malaria prophylaxis and treatment in the Republic of Korea (ROK) military personnel from 1997. Although prophylaxis is generally regarded as successful among ROK military, prophylaxis failure has been repeatedly reported. Before the prophylaxis program was started on July 4th 2011, which was completed on October 16th 2011, by the ROK military, more than 60% of malaria cases were attributed to new infection or long-latency relapse. During the prophylaxis program, the authors re-examined the efficiency of chloroquine chemoprophylaxis in ROK military during the last 6 months of 2011 by measuring compliance and whole blood chloroquine levels in 41 malaria patients immediately before instituting antimalarial therapy between July and December. Three patients (7.3%) showed good compliance, and had whole blood total chloroquine levels above the minimally inhibitory concentration (100 ng/mL). However, 28 (69.3%) of these 41 patients when admitted to hospital showed poor or no compliance with prophylaxis; 4 of the 28 (14.3%) were stationed outside the mass prophylaxis region, and 5 (17.9%) subjects were infected after the prophylaxis program had finished. These findings indicate that the current malaria control program should be carefully reconsidered, in terms of, individual instruction, current chemoprophylaxis program regimens, and schedules to improve the efficacy of prophylaxis in the ROK military.
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Battle KE, Gething PW, Elyazar IRF, Moyes CL, Sinka ME, Howes RE, Guerra CA, Price RN, Baird KJ, Hay SI. The global public health significance of Plasmodium vivax. ADVANCES IN PARASITOLOGY 2013. [PMID: 23199486 DOI: 10.1016/b978-0-12-397900-1.00001-3] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Plasmodium vivax occurs globally and thrives in both temperate and tropical climates. Here, we review the evidence of the biological limits of its contemporary distribution and the global population at risk (PAR) of the disease within endemic countries. We also review the most recent evidence for the endemic level of transmission within its range and discuss the implications for burden of disease assessments. Finally, the evidence-base for defining the contemporary distribution and PAR of P. vivax are discussed alongside a description of the vectors of human malaria within the limits of risk. This information along with recent data documenting the severe morbid and fatal consequences of P. vivax infection indicates that the public health significance of P. vivax is likely to have been seriously underestimated.
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Affiliation(s)
- Katherine E Battle
- Department of Zoology, University of Oxford, South Parks Road, Oxford, UK
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Yoo DH, Shin EH, Park MY, Kim HC, Lee DK, Lee HH, Kim HK, Chang KS. Mosquito species composition and Plasmodium vivax infection rates for Korean army bases near the demilitarized zone in the Republic of Korea, 2011. Am J Trop Med Hyg 2012; 88:24-8. [PMID: 23243112 DOI: 10.4269/ajtmh.2012.11-0755] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Vivax malaria is a significant military and civilian health threat in northern Republic of Korea (ROK). Mosquito collections were performed at two ROK army installations, Paju near the demilitarized zone (DMZ) using black light traps in 2011. The DMZ, a 4 km wide border, is the northernmost point of the ROK and separates the ROK from the Democratic People's Republic of Korea (DPRK). Anopheles spp. were identified by polymerase chain reaction and screened for Plasmodium vivax sporozoites. Of 4,354 female Anopheles mosquitoes identified, Anopheles kleini (61.8%) was the most frequently collected, followed by Anopheles pullus (16.0%), Anopheles belenrae (9.0%), Anopheles sinensis (7.4%), Anopheles sineroides (4.2%), and Anopheles lesteri (1.6%). Anopheles kleini, An. pullus, and An. sineroides showed the highest population densities in June, whereas population densities were highest for An. belenrae, An. lesteri, and An. sinensis in August. The maximum likelihood estimation (estimated number of positive mosquitoes/1,000) for P. vivax was highest for An. lesteri (28.9), followed by An. sineroides (23.3), An. belenrae (15.8), An. sinensis (9.6), An. pullus (5.8) and An. kleini (4.2). The seasonal maximum likelihood estimation (MLE) values were variable among Anopheles species. Anopheles belenrae, An. Pullus, and An. sineroides showed the highest seasonal MLE's in July, whereas An. lesteri and An. sinensis exhibited the highest seasonal MLEs in September and An. kleini during August. This is the first report implicating An. sineroides as a vector of P. vivax in the ROK, and extends our knowledge of the distribution and potential role in malaria transmission.
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Affiliation(s)
- Dae-Hyun Yoo
- National Institute of Health, Korea Center for Disease Control and Prevention, Chungbuk, Republic of Korea.
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Zhang Y, Liu QY, Luan RS, Liu XB, Zhou GC, Jiang JY, Li HS, Li ZF. Spatial-temporal analysis of malaria and the effect of environmental factors on its incidence in Yongcheng, China, 2006-2010. BMC Public Health 2012; 12:544. [PMID: 22823998 PMCID: PMC3488337 DOI: 10.1186/1471-2458-12-544] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 06/30/2012] [Indexed: 11/30/2022] Open
Abstract
Background In 2003, Plasmodium vivax malaria has re-emerged in central eastern China including Yongcheng prefecture, Henan Province, where no case has been reported for eleven years. Our goals were to detect the space-time distribution pattern of malaria and to determine significant environmental variables contributing to malaria incidence in Yongcheng from 2006 to 2010, thus providing scientific basis for further optimizing current malaria surveillance and control programs. Methods This study examined the spatial and temporal heterogeneities in the risk of malaria and the influencing factors on malaria incidence using geographical information system (GIS) and time series analysis. Univariate analysis was conducted to estimate the crude correlations between malaria incidence and environmental variables, such as mosquito abundance and climatic factors. Multivariate analysis was implemented to construct predictive models to explore the principal environmental determinants on malaria epidemic using a Generalized Estimating Equation (GEE) approach. Results Annual malaria incidence at town-level decreased from the north to south, and monthly incidence at prefecture-level demonstrated a strong seasonal pattern with a peak from July to November. Yearly malaria incidence had a visual spatial association with yearly average temperature. Moreover, the best-fit temporal model (model 2) (QIC = 16.934, P<0.001, R2 = 0.818) indicated that significant factors contributing to malaria incidence were maximum temperature at one month lag, average humidity at one month lag, and malaria incidence of the previous month. Conclusions Findings supported the effects of environment factors on malaria incidence and indicated that malaria control targets should vary with intensity of malaria incidence, with more public resource allocated to control the source of infections instead of large scale An. sinensis control when malaria incidence was at a low level, which would benefit for optimizing the malaria surveillance project in China and some other countries with unstable or low malaria transmission.
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Affiliation(s)
- Yan Zhang
- State Key Laboratory for Infectious Diseases Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
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Cui L, Yan G, Sattabongkot J, Cao Y, Chen B, Chen X, Fan Q, Fang Q, Jongwutiwes S, Parker D, Sirichaisinthop J, Kyaw MP, Su XZ, Yang H, Yang Z, Wang B, Xu J, Zheng B, Zhong D, Zhou G. Malaria in the Greater Mekong Subregion: heterogeneity and complexity. Acta Trop 2012. [PMID: 21382335 DOI: 10.1016/j.actatropica.2011.02.016.malaria] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2023]
Abstract
The Greater Mekong Subregion (GMS), comprised of six countries including Cambodia, China's Yunnan Province, Lao PDR, Myanmar (Burma), Thailand and Vietnam, is one of the most threatening foci of malaria. Since the initiation of the WHO's Mekong Malaria Program a decade ago, malaria situation in the GMS has greatly improved, reflected in the continuous decline in annual malaria incidence and deaths. However, as many nations are moving towards malaria elimination, the GMS nations still face great challenges. Malaria epidemiology in this region exhibits enormous geographical heterogeneity with Myanmar and Cambodia remaining high-burden countries. Within each country, malaria distribution is also patchy, exemplified by 'border malaria' and 'forest malaria' with high transmission occurring along international borders and in forests or forest fringes, respectively. 'Border malaria' is extremely difficult to monitor, and frequent malaria introductions by migratory human populations constitute a major threat to neighboring, malaria-eliminating countries. Therefore, coordination between neighboring countries is essential for malaria elimination from the entire region. In addition to these operational difficulties, malaria control in the GMS also encounters several technological challenges. Contemporary malaria control measures rely heavily on effective chemotherapy and insecticide control of vector mosquitoes. However, the spread of multidrug resistance and potential emergence of artemisinin resistance in Plasmodium falciparum make resistance management a high priority in the GMS. This situation is further worsened by the circulation of counterfeit and substandard artemisinin-related drugs. In most endemic areas of the GMS, P. falciparum and Plasmodium vivax coexist, and in recent malaria control history, P. vivax has demonstrated remarkable resilience to control measures. Deployment of the only registered drug (primaquine) for the radical cure of vivax malaria is severely undermined due to high prevalence of glucose-6-phosphate dehydrogenase deficiency in target human populations. In the GMS, the dramatically different ecologies, diverse vector systems, and insecticide resistance render traditional mosquito control less efficient. Here we attempt to review the changing malaria epidemiology in the GMS, analyze the vector systems and patterns of malaria transmission, and identify the major challenges the malaria control community faces on its way to malaria elimination.
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Affiliation(s)
- Liwang Cui
- Department of Entomology, The Pennsylvania State University, University Park, 16801, USA.
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Cui L, Yan G, Sattabongkot J, Cao Y, Chen B, Chen X, Fan Q, Fang Q, Jongwutiwes S, Parker D, Sirichaisinthop J, Kyaw MP, Su XZ, Yang H, Yang Z, Wang B, Xu J, Zheng B, Zhong D, Zhou G. Malaria in the Greater Mekong Subregion: heterogeneity and complexity. Acta Trop 2012; 121:227-39. [PMID: 21382335 DOI: 10.1016/j.actatropica.2011.02.016] [Citation(s) in RCA: 167] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 02/18/2011] [Accepted: 02/26/2011] [Indexed: 10/18/2022]
Abstract
The Greater Mekong Subregion (GMS), comprised of six countries including Cambodia, China's Yunnan Province, Lao PDR, Myanmar (Burma), Thailand and Vietnam, is one of the most threatening foci of malaria. Since the initiation of the WHO's Mekong Malaria Program a decade ago, malaria situation in the GMS has greatly improved, reflected in the continuous decline in annual malaria incidence and deaths. However, as many nations are moving towards malaria elimination, the GMS nations still face great challenges. Malaria epidemiology in this region exhibits enormous geographical heterogeneity with Myanmar and Cambodia remaining high-burden countries. Within each country, malaria distribution is also patchy, exemplified by 'border malaria' and 'forest malaria' with high transmission occurring along international borders and in forests or forest fringes, respectively. 'Border malaria' is extremely difficult to monitor, and frequent malaria introductions by migratory human populations constitute a major threat to neighboring, malaria-eliminating countries. Therefore, coordination between neighboring countries is essential for malaria elimination from the entire region. In addition to these operational difficulties, malaria control in the GMS also encounters several technological challenges. Contemporary malaria control measures rely heavily on effective chemotherapy and insecticide control of vector mosquitoes. However, the spread of multidrug resistance and potential emergence of artemisinin resistance in Plasmodium falciparum make resistance management a high priority in the GMS. This situation is further worsened by the circulation of counterfeit and substandard artemisinin-related drugs. In most endemic areas of the GMS, P. falciparum and Plasmodium vivax coexist, and in recent malaria control history, P. vivax has demonstrated remarkable resilience to control measures. Deployment of the only registered drug (primaquine) for the radical cure of vivax malaria is severely undermined due to high prevalence of glucose-6-phosphate dehydrogenase deficiency in target human populations. In the GMS, the dramatically different ecologies, diverse vector systems, and insecticide resistance render traditional mosquito control less efficient. Here we attempt to review the changing malaria epidemiology in the GMS, analyze the vector systems and patterns of malaria transmission, and identify the major challenges the malaria control community faces on its way to malaria elimination.
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Dhiman S, Yadav K, Goswami D, Das NG, Baruah I, Singh L. Epidemiology and Risk Analysis of Malaria among Pregnant Women. IRANIAN JOURNAL OF PUBLIC HEALTH 2012; 41:1-8. [PMID: 23113116 PMCID: PMC3481657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Accepted: 11/22/2011] [Indexed: 11/04/2022]
Abstract
Malaria remains a complex problem during the pregnancy, which threatens > 35 millions pregnant women every year. Malaria pathogenesis in pregnancy results in accumulation of infected RBCs in the intervillous spaces causing severe alterations leading to the reduced materno-foetal exchanges. In this article we have revisited the current evidences of clinical implications and overall burden of malaria in pregnancy. Many adverse aftermaths including, low birth weight, intrauterine growth retardation, preterm delivery, stillbirth and anemia were found associated with malaria in pregnant women. Despite of worldwide comprehensive control programmes for malaria in pregnancy, the disease control has been a daunting task everywhere. Socio cultural, economical, lack of awareness and various logistic problems compound the disease in developing countries. Thorough evidence based information and estimates, education and awareness and strengthening of prevention programmes are needed urgently to achieve success in malaria control in pregnancy.
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Affiliation(s)
- S Dhiman
- Corresponding Author: Tel: +91 3712 258538/ 34, E-mail address: Sunil Dhiman –
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12
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Sinka ME, Bangs MJ, Manguin S, Chareonviriyaphap T, Patil AP, Temperley WH, Gething PW, Elyazar IRF, Kabaria CW, Harbach RE, Hay SI. The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis. Parasit Vectors 2011; 4:89. [PMID: 21612587 PMCID: PMC3127851 DOI: 10.1186/1756-3305-4-89] [Citation(s) in RCA: 317] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 05/25/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed. RESULTS Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented. CONCLUSIONS This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.
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Affiliation(s)
- Marianne E Sinka
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Michael J Bangs
- Public Health and Malaria Control Department, PT Freeport Indonesia, Kuala Kencana, Papua, Indonesia
| | - Sylvie Manguin
- Institut de Recherche pour le Développement, Lab. d'Immuno-Physiopathologie Moléculaire Comparée, UMR-MD3/Univ. Montpellier 1, Faculté de Pharmacie, 15, Ave Charles Flahault, 34093 Montpellier, France
| | | | - Anand P Patil
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - William H Temperley
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Peter W Gething
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | | | - Caroline W Kabaria
- Malaria Public Health and Epidemiology Group, Centre for Geographic Medicine, KEMRI - Univ. Oxford - Wellcome Trust Collaborative Programme, Kenyatta National Hospital Grounds, P.O. Box 43640-00100 Nairobi, Kenya
| | - Ralph E Harbach
- Department of Entomology, The Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Simon I Hay
- Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
- Malaria Public Health and Epidemiology Group, Centre for Geographic Medicine, KEMRI - Univ. Oxford - Wellcome Trust Collaborative Programme, Kenyatta National Hospital Grounds, P.O. Box 43640-00100 Nairobi, Kenya
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Bitoh T, Fueda K, Ohmae H, Watanabe M, Ishikawa H. Risk analysis of the re-emergence of Plasmodium vivax malaria in Japan using a stochastic transmission model. Environ Health Prev Med 2011; 16:171-7. [PMID: 21431796 DOI: 10.1007/s12199-010-0184-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 09/29/2010] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVES This study analyzed the risk of infection with Plasmodium vivax in local residents through a stochastic simulation in which an infected tourist, local resident, or immigrants from an endemic area would visit Himi-shi, Toyama prefecture, which is a formerly endemic area in Japan. METHODS In Toyama, the habitats of Anopheles sinensis, which can transmit P. vivax, have been examined previously. We constructed a stochastic model of P. vivax transmission that can handle small numbers of infected persons and infected mosquitoes. The seasonal fluctuation in the numbers of captured An. sinensis was taken into account in the model. RESULTS Ten thousand trial simulations were carried out stochastically with a range of human blood indexes (HBI) of 1-10% for a range of months (June-September). The simulation results for a realistic assumption of a 1% HBI showed that the risk of infection for local residents was low (below 1%) except for the immigrants scenario. CONCLUSIONS The risk of infection among local residents (second cycle) was estimated to be very low for all situations. Therefore, there is little possibility for P. vivax infection to become established in this area of Japan.
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Affiliation(s)
- Tomoyuki Bitoh
- Department of Human Ecology, Graduate School of Environmental Science, Okayama University, Okayama, 700-8530, Japan
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Ermert V, Fink AH, Jones AE, Morse AP. Development of a new version of the Liverpool Malaria Model. I. Refining the parameter settings and mathematical formulation of basic processes based on a literature review. Malar J 2011; 10:35. [PMID: 21314922 PMCID: PMC3055220 DOI: 10.1186/1475-2875-10-35] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 02/11/2011] [Indexed: 11/10/2022] Open
Abstract
Background A warm and humid climate triggers several water-associated diseases such as malaria. Climate- or weather-driven malaria models, therefore, allow for a better understanding of malaria transmission dynamics. The Liverpool Malaria Model (LMM) is a mathematical-biological model of malaria parasite dynamics using daily temperature and precipitation data. In this study, the parameter settings of the LMM are refined and a new mathematical formulation of key processes related to the growth and size of the vector population are developed. Methods One of the most comprehensive studies to date in terms of gathering entomological and parasitological information from the literature was undertaken for the development of a new version of an existing malaria model. The knowledge was needed to allow the justification of new settings of various model parameters and motivated changes of the mathematical formulation of the LMM. Results The first part of the present study developed an improved set of parameter settings and mathematical formulation of the LMM. Important modules of the original LMM version were enhanced in order to achieve a higher biological and physical accuracy. The oviposition as well as the survival of immature mosquitoes were adjusted to field conditions via the application of a fuzzy distribution model. Key model parameters, including the mature age of mosquitoes, the survival probability of adult mosquitoes, the human blood index, the mosquito-to-human (human-to-mosquito) transmission efficiency, the human infectious age, the recovery rate, as well as the gametocyte prevalence, were reassessed by means of entomological and parasitological observations. This paper also revealed that various malaria variables lack information from field studies to be set properly in a malaria modelling approach. Conclusions Due to the multitude of model parameters and the uncertainty involved in the setting of parameters, an extensive literature survey was carried out, in order to produce a refined set of settings of various model parameters. This approach limits the degrees of freedom of the parameter space of the model, simplifying the final calibration of undetermined parameters (see the second part of this study). In addition, new mathematical formulations of important processes have improved the model in terms of the growth of the vector population.
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Affiliation(s)
- Volker Ermert
- Institute of Geophysics and Meteorology, University of Cologne, Cologne, Germany.
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Ng LC, Lee KS, Tan CH, Ooi PL, Lam-Phua SG, Lin R, Pang SC, Lai YL, Solhan S, Chan PP, Wong KY, Ho ST, Vythilingam I. Entomologic and molecular investigation into Plasmodium vivax transmission in Singapore, 2009. Malar J 2010; 9:305. [PMID: 21029478 PMCID: PMC2988040 DOI: 10.1186/1475-2875-9-305] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 10/29/2010] [Indexed: 11/10/2022] Open
Abstract
Background Singapore has been certified malaria free since November 1982 by the World Health Organization and despite occasional local transmission, the country has maintained the standing. In 2009, three clusters of malaria cases were reported in Singapore. Methods Epidemiological, entomological and molecular studies were carried out to investigate the three clusters, namely Mandai-Sungei Kadut, Jurong Island and Sembawang. Results A total of 29 malaria patients, with no recent travel history, were reported in the three clusters. Molecular analysis based on the msp3α and msp1 genes showed two independent local transmissions: one in Mandai-Sungei Kadut and another in Sembawang. Almost all cases within each cluster were epidemiologically linked. In Jurong Island cluster, epidemiological link remains uncertain, as almost all cases had a unique genetic profile. Only two cases shared a common profile and were found to be linked to the Mandai-Sungei Kadut cluster. Entomological investigation found Anopheles sinensis to be the predominant Anopheline in the two areas where local transmission of P. vivax was confirmed. Anopheles sinensis was found to be attracted to human bait and bites as early as 19:45 hrs. However, all Anopheles mosquitoes caught were negative for sporozoites and oocysts by dissection. Conclusion Investigation of P. vivax cases from the three cluster areas confirmed the occurrence of local transmission in two areas. Although An. sinensis was the predominant Anopheline found in areas with confirmed transmission, the vector/s responsible for the outbreaks still remains cryptic.
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Affiliation(s)
- Lee-Ching Ng
- Environmental Health Institute, National Environment Agency, 11 Biopolis Way, Singapore 138667.
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Nah K, Kim Y, Lee JM. The dilution effect of the domestic animal population on the transmission of P. vivax malaria. J Theor Biol 2010; 266:299-306. [PMID: 20619273 DOI: 10.1016/j.jtbi.2010.06.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Revised: 06/23/2010] [Accepted: 06/23/2010] [Indexed: 11/25/2022]
Abstract
The diversion of disease carrying insect from humans to animals may reduce transmission of diseases such as malaria. The use of animals to mitigate mosquito bites on human is called 'zooprophylaxis'. We introduce a mathematical model for Plasmodium vivax malaria transmission with two bloodmeal hosts (humans and domestic animals) to study the effect of zooprophylaxis. After computing the basic reproduction number from the proposed model, we explore how perturbations in the parameters, sensitive to the effects of control measures, affect its value. Zooprophylaxis is shown to determine whether a basic reproduction becomes bigger than an outbreak threshold value or not. Sensitivity analysis shows that increasing the relative animal population size works better in P. vivax malaria control than decreasing the mosquito population when the relative animal population size is larger than a threshold value.
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Affiliation(s)
- Kyeongah Nah
- Department of Mathematics, Kyungpook National University, Daegu 702-701, Republic of Korea
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Lee HI, Seo BY, Shin EH, Burkett DA, Lee JK, Shin YH. Efficiency evaluation of Nozawa-style black light trap for control of anopheline mosquitoes. THE KOREAN JOURNAL OF PARASITOLOGY 2009; 47:159-65. [PMID: 19488423 DOI: 10.3347/kjp.2009.47.2.159] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 02/13/2009] [Accepted: 03/31/2009] [Indexed: 11/23/2022]
Abstract
House-residual spraying and insecticide-treated bed nets have achieved some success in controlling anthropophilic and endophagic vectors. However, these methods have relatively low efficacy in Korea because Anopheles sinensis, the primary malaria vector, is highly zoophilic and exophilic. So, we focused our vector control efforts within livestock enclosures using ultraviolet black light traps as a mechanical control measure. We found that black light traps captured significantly more mosquitoes at 2 and 2.5 m above the ground (P < 0.05). We also evaluated the effectiveness of trap spacing within the livestock enclosure. In general, traps spaced between 4 and 7 m apart captured mosquitoes more efficiently than those spaced closer together (P > 0.05). Based on these findings, we concluded that each black light trap in the livestock enclosures killed 7,586 female mosquitoes per trap per night during the peak mosquito season (July-August). In May-August 2003, additional concurrent field trials were conducted in Ganghwa county. We got 74.9% reduction (P < 0.05) of An. sinensis in human dwellings and 61.5% reduction (P > 0.05) in the livestock enclosures. The black light trap operation in the livestock enclosures proved to be an effective control method and should be incorporated into existing control strategies in developed countries.
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Affiliation(s)
- Hee Il Lee
- Division of Medical Entomology, National Institute of Health, Korea Centers for Disease Control and Prevention, Seoul, Korea
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Lee WJ, Klein TA, Kim HC, Choi YM, Yoon SH, Chang KS, Chong ST, Lee IY, Jones JW, Jacobs JS, Sattabongkot J, Park JS. Anopheles kleini, Anopheles pullus, and Anopheles sinensis: potential vectors of Plasmodium vivax in the Republic of Korea. JOURNAL OF MEDICAL ENTOMOLOGY 2007; 44:1086-1090. [PMID: 18047210 DOI: 10.1603/0022-2585(2007)44[1086:akapaa]2.0.co;2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Anopheles sinensis Wiedemann (63.3%) was the most abundant Anopheles mosquito captured at cowshed resting collections in malaria high-risk areas (northern Gyeonggi Province) near the demilitarized zone (DMZ) in Korea during 2005, followed by Anopheles kleini Rueda (24.7%) and Anopheles pullus M. Yamada (8.7%). At cowshed resting collections in malaria low-risk areas (Jeonnam and Gyeongnam provinces), An. sinensis accounted for 96.8% of all Anopheles spp. collected, followed by An. kleini Rueda (2.7%), whereas no An. pullus were collected. Three species, An. kleini (50.9%), An. pullus (29.0%), and An. sinensis (13.8%), accounted for nearly all of the 224 Anopheles spp. captured by New Jersey light trap near the DMZ. In addition, An. pullus and An. kleini captured by New Jersey light trap near the DMZ and assayed by enzyme linked immunosorbent assay for Plasmodium vivax circumsporozoite antigen concentrations were higher than An. sinensis sensu stricto (s.s.), indicating higher levels of sporozoites. In laboratory studies of four concurrent artificial membrane feedings on malaria-infected blood from patients, F1 progeny of An. kleini and An. pullus had higher infection rates (8.8 and 7.5%, respectively) than An. sinensis s.s. (4.2%). These data suggest that An. kleini and An. pullus and An. sinensis are vectors of malaria in Korea. Further studies are required to determine the role of these species in the transmission of P. vivax in the Republic of Korea.
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Affiliation(s)
- Won-Ja Lee
- Department of Medical Entomology, Korea Center for Disease Control and Prevention, Eunpyung-Gu, Seoul, 122-701, Korea
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Wyse APP, Bevilacqua L, Rafikov M. Simulating malaria model for different treatment intensities in a variable environment. Ecol Modell 2007. [DOI: 10.1016/j.ecolmodel.2007.03.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ree HI. Studies on Anopheles sinensis, the vector species of vivax malaria in Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2005; 43:75-92. [PMID: 16192749 PMCID: PMC2712014 DOI: 10.3347/kjp.2005.43.3.75] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Extensive previous studies on taxonomy, behavior/bionomics and control of Anopheles sinensis are reviewed and summarized. Recent molecular identification revealed that the population of An. sinensis complex includes An. sinensis, An. pullus, An. lesteri and at least two new species, and An. yatsushiroensis is synonmy of An. pullus. An. sinensis is the main vector species of vivax malaria in Korea. Larvae of An. sinensis breed in wide range of habitats which are naturally-made clean water, stagnant or flowing; main habitats include rice fields, ditches, streams, irrigation canals, marshes, ponds, ground pools, etc. Their host preferences are highly zoophilic. Human blood rate is very low (0.7-1.7%); nevertheless An. sinensis readily feeds on man when domestic animals are not found near by. They feed on hosts throughout the night from dusk to dawn with a peak period of 02:00-04:00 hours; they are slightly more exophagic (biting outdoors); much larger numbers come into the room when light is on. Main resting places are outdoors such as grasses, vegetable fields and rice fields. A mark-release-recapture study resulted that 37.1% was recaptured within 1 km, 29.4% at 1-3 km, 21.1% at 3-6 km, 10.3% at 6-9 km and 2.1% at 9-12 km distance. An. sinensis hibernate outdoors (mostly under part of dense grasses) during October-March. At the end of the hibernation period (March-April) they feed on cows at daytime. Until today any single measure to effectively control An. sinensis population has not been found. Indoor residual spray with a long-lasting insecticide can not reduce vector population densities, but shorten their life spans in some degree, so contributes to malaria control.
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Affiliation(s)
- Han Il Ree
- Department of Parasitology and Institute of Tropical Medicine, College of Medicine, Yonsei University, Seoul 120-752, Korea.
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Rudolf VHW, Antonovics J. Species Coexistence and Pathogens with Frequency‐Dependent Transmission. Am Nat 2005; 166:112-8. [PMID: 15937794 DOI: 10.1086/430674] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Accepted: 03/17/2005] [Indexed: 11/03/2022]
Abstract
Pathogens that infect multiple hosts are commonly transmitted by vectors, and their transmission rate is often thought to depend on the proportion of hosts or vectors infected (i.e., frequency dependence). A model of a two-host, one-pathogen system with frequency-dependent transmission is used to investigate how sharing a pathogen with an alternative host influences pathogen-mediated extinction. The results show that if there is frequency-dependent transmission, a host can be rescued from pathogen-mediated extinction by the presence of a second host with which it shares a pathogen. The study provides an important conceptual counterexample to the idea that shared pathogens necessarily result in apparent competition by showing that shared pathogens can mediate apparent mutualism. We distinguish two types of dilution effect (pathogen reduction with increasing host diversity), each resulting from different underlying pathogen transmission processes and host density effects. These results have important consequences for understanding the role of pathogens in species interactions and in maintaining host species diversity.
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Affiliation(s)
- Volker H W Rudolf
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904-4327, USA.
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Lee KJ, Kim CB, Choi BJ, Park KH, Park JK. Analysis of vivax malaria cases in Gangwon-do (province), Korea in the year 2000. THE KOREAN JOURNAL OF PARASITOLOGY 2001; 39:301-6. [PMID: 11775330 PMCID: PMC2721215 DOI: 10.3347/kjp.2001.39.4.301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A total of 827 malaria cases were reported in the Gangwon-do in the year 2000. There were 18.2 cases per 100,000 inhabitants. There were 283 cases among civilians and 544 cases among the military. 90.6% of cases were reported in Cheorwon--(531), Hwacheon--(152), and Goseong--(66) gun (county), which bordered the demilitarized zone (DMZ). A distinct feature pertaining to the malaria cases in Gangwon-do is that the number of cases has increased about two times over the last year. The mean time from the beginning of symptoms to malaria diagnosis was five days. Control systems for malaria by public health organizations and military organizations are well maintained, but were not able to reduce the malaria prevalence rate. The cause for the increase in pattern of the malaria cases in Gangwon-do may be caused by the spreading of prevalent areas of malaria to the east. Continuous endeavor such as early detection of cases, early treatment, education on clinical symptoms and prevention of mosquito bites with repellent and mosquito nets will help to reduce the infection rate of malaria in Gangwon-do.
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Affiliation(s)
- K J Lee
- Department of Parasitology, Yonsei University Wonju College of Medicine, Korea
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