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submicroscopic malaria

Mandingha Kosso Etoka-Beka, Francine Ntoumi, Michael Kombo, Julia Deibert, Pierre Poulain, Christevy Vouvoungui, Simon Charles Kobawila, Felix Koukouikila-Koussounda
OBJECTIVES: To investigate the proportion of malaria infection in febrile children consulting a paediatric hospital in Brazzaville, to determine the prevalence of submicroscopic malaria infection, to characterise Plasmodium falciparum infection and compare the prevalence of uncomplicated P. falciparum malaria according to haemoglobin profiles. METHODS: Blood samples were collected from children aged <10 years with an axillary temperature ≥37.5 °C consulting the paediatric ward of Marien Ngouabi Hospital in Brazzaville...
September 27, 2016: Tropical Medicine & International Health: TM & IH
John Rek, Shereen Katrak, Hannah Obasi, Patience Nayebare, Agaba Katureebe, Elijah Kakande, Emmanuel Arinaitwe, Joaniter I Nankabirwa, Prasanna Jagannathan, Chris Drakeley, Sarah G Staedke, David L Smith, Teun Bousema, Moses Kamya, Philip J Rosenthal, Grant Dorsey, Bryan Greenhouse
BACKGROUND: Parasite prevalence is a key metric used to quantify the burden of malaria and assess the impact of control strategies. Most published estimates of parasite prevalence are based on microscopy and likely underestimate true prevalence. METHODS: Thick smear microscopy was performed in cohorts of children (aged 6 month to 10 years) and adults every 90 days over 2 years, at three sites of varying transmission intensity in Uganda. Microscopy-negative samples were tested for sub-microscopic parasitaemia using loop-mediated isothermal amplification (LAMP)...
2016: Malaria Journal
Shirley Evelyn Lennon, Adolfo Miranda, Juliana Henao, Andres F Vallejo, Julianh Perez, Alvaro Alvarez, Myriam Arévalo-Herrera, Sócrates Herrera
BACKGROUND: Even though malaria incidence has decreased substantially in Guatemala since 2000, Guatemala remains one of the countries with the highest malaria transmission in Mesoamerica. Guatemala is committed to eliminating malaria as part of the initiative 'Elimination of Malaria in Mesoamerica and the Island of Hispaniola' (EMMIE); however, it is still in the control phase. During the past decade, the government strengthened malaria control activities including mass distribution of long-lasting insecticide-impregnated bed nets, early diagnosis and prompt treatment...
2016: Malaria Journal
Zhiyong Zhou, Rebecca M Mitchell, Simon Kariuki, Christopher Odero, Peter Otieno, Kephas Otieno, Philip Onyona, Vincent Were, Ryan E Wiegand, John E Gimnig, Edward D Walker, Meghna Desai, Ya Ping Shi
BACKGROUND: Although malaria control intervention has greatly decreased malaria morbidity and mortality in many African countries, further decline in parasite prevalence has stagnated in western Kenya. In order to assess if malaria transmission reservoir is associated with this stagnation, submicroscopic infection and gametocyte carriage was estimated. Risk factors and associations between malaria control interventions and gametocyte carriage were further investigated in this study. METHODS: A total of 996 dried blood spot samples were used from two strata, all smear-positives (516 samples) and randomly selected smear-negatives (480 samples), from a community cross-sectional survey conducted at peak transmission season in 2012 in Siaya County, western Kenya...
2016: Malaria Journal
Elisabeth Baum, Jetsumon Sattabongkot, Jeeraphat Sirichaisinthop, Kirakorn Kiattibutr, Aarti Jain, Omid Taghavian, Ming-Chieh Lee, D Huw Davies, Liwang Cui, Philip L Felgner, Guiyun Yan
BACKGROUND: Despite largely successful control efforts, malaria remains a significant public health problem in Thailand. Based on microscopy, the northwestern province of Tak, once Thailand's highest burden area, is now considered a low-transmission region. However, microscopy is insensitive to detect low-level parasitaemia, causing gross underestimation of parasite prevalence in areas where most infections are subpatent. The objective of this study was to assess the current epidemiology of malaria prevalence using molecular and serological detection methods, and to profile the antibody responses against Plasmodium as it relates to age, seasonal changes and clinical manifestations during infection...
2016: Malaria Journal
Irène Pegha Moukandja, Jean Claude Biteghe Bi Essone, Issaka Sagara, Roland Fabrice Kassa Kassa, Julien Ondzaga, Jean-Bernard Lékana Douki, Marielle Bouyou Akotet, Dieudonne Nkoghe Mba, Fousseyni S Touré Ndouo
Control strategies implemented a decade ago led to a marked reduction in the prevalence of malaria in many countries. In Dienga, southeastern Gabon, the prevalence of microscopic P. falciparum infection was 7% in 2003, close to the pre-elimination threshold of 5%. The aim of this work was to determine the prevalence of P. falciparum infection in the same community a decade later. A cohort of 370 individuals aged from 3 to 85 years living in Dienga was investigated for P. falciparum infection; during six passages (P) in 15-month period...
2016: PloS One
Marcelo U Ferreira, Marcia C Castro
Brazil currently contributes 42 % of all malaria cases reported in the Latin America and the Caribbean, a region where major progress towards malaria elimination has been achieved in recent years. In 2014, malaria burden in Brazil (143,910 microscopically confirmed cases and 41 malaria-related deaths) has reached its lowest levels in 35 years, Plasmodium falciparum is highly focal, and the geographic boundary of transmission has considerably shrunk. Transmission in Brazil remains entrenched in the Amazon Basin, which accounts for 99...
2016: Malaria Journal
Qinghui Wang, Zhenjun Zhao, Xuexing Zhang, Xuelian Li, Min Zhu, Peipei Li, Zhaoqing Yang, Ying Wang, Guiyun Yan, Hong Shang, Yaming Cao, Qi Fan, Liwang Cui
Understanding naturally acquired immunity to infections caused by Plasmodia in different malaria endemicity settings is needed for better vaccine designs and for exploring antibody responses as a proxy marker of malaria transmission intensity. This study investigated the sero-epidemiology of malaria along the international border between China and Myanmar, where malaria elimination action plans are in place. This study recruited 233 P. vivax and 156 P. falciparum infected subjects with acute malaria at the malaria clinics and hospitals...
2016: PloS One
Diego F Echeverry, Nicholas A Deason, Jenna Davidson, Victoria Makuru, Honglin Xiao, Julie Niedbalski, Marcia Kern, Tanya L Russell, Thomas R Burkot, Frank H Collins, Neil F Lobo
BACKGROUND: Nested PCRs based on the Plasmodium 18s-rRNA gene have been extensively used for human malaria diagnosis. However, they are not practical when large quantities of samples need to be processed, further there have been challenges in the performance and when interpreting results, especially when submicroscopic infections are analysed. Here the use of "direct PCR" was investigated with the aim of improving diagnosis in the malaria elimination era. METHODS: The performance of the Plasmodium cytochrome oxidase III gene (COX-III) based novel malaria detection strategies (direct nested PCR and direct single PCR) were compared using a 18s-rRNA direct nested PCR as a reference tool...
2016: Malaria Journal
Sumudu Britton, Qin Cheng, Matthew J Grigg, Catherine B Poole, Cielo Pasay, Timothy William, Kimberley Fornace, Nicholas M Anstey, Colin J Sutherland, Chris Drakeley, James S McCarthy
INTRODUCTION: Plasmodium vivax malaria has a wide geographic distribution and poses challenges to malaria elimination that are likely to be greater than those of P. falciparum. Diagnostic tools for P. vivax infection in non-reference laboratory settings are limited to microscopy and rapid diagnostic tests but these are unreliable at low parasitemia. The development and validation of a high-throughput and sensitive assay for P. vivax is a priority. METHODS: A high-throughput LAMP assay targeting a P...
February 2016: PLoS Neglected Tropical Diseases
Maha A Elbadry, Basima Al-Khedery, Massimiliano S Tagliamonte, Charles A Yowell, Christian P Raccurt, Alexandre Existe, Jacques Boncy, Thomas A Weppelmann, Valery E M Beau De Rochars, Jean F Lemoine, Bernard A Okech, John B Dame
BACKGROUND: Public health measures are poised for transition from malaria control to malaria elimination on the island of Hispaniola. Assessment of the reservoir of asymptomatic infections from which acute malaria cases may derive is critical to plan and evaluate elimination efforts. Current field technology is ill suited for detecting sub-microscopic infections, thus highly sensitive survey methods capable of detecting virtually all infections are needed. In this study the prevalence of infection with Plasmodium falciparum was determined in patients seeking medical care primarily for non-febrile conditions in six departments in Haiti using a newly designed qRT-PCR-based assay...
2015: Malaria Journal
Rashad Abdul-Ghani, Leonardo K Basco, John C Beier, Mohammed A K Mahdy
Standard anti-malarial drug efficacy and drug resistance assessments neglect the gametocyte parameters in their protocols. With the spread of drug resistance and the absence of clinically proven vaccines, the use of gametocytocidal drugs or drug combinations with transmission-blocking activity is a high priority for malaria control and elimination. However, the limited repertoire of gametocytocidal drugs and induction of gametocytogenesis after treatment with certain anti-malarial drugs necessitate both regular monitoring of gametocytocidal activities of anti-malarial drugs in clinical use and the effectiveness of candidate gametocytocidal agents...
2015: Malaria Journal
Ekene K Nwaefuna, Richmond Afoakwah, Verner N Orish, Alexander Egyir-Yawson, Johnson N Boampong
Malaria infections undetectable by microscopy but detectable by Polymerase Chain Reaction (PCR) (submicroscopic malaria) are common in endemic areas like Ghana. Submicroscopic malaria has been linked with severe pregnancy outcomes as well as contributing to malaria transmission. In this cross-sectional study 872 consenting pregnant women (gestation ≥ 20 weeks) were recruited from 8 hospitals in Central Region, Ghana, between July and December 2009. Malaria infection was detected by microscopy and PCR. Haemoglobin was measured and anaemia was defined as haemoglobin lower than 11 g/dL...
2015: Journal of Parasitology Research
Kimberly M Fornace, Nor Afizah Nuin, Martha Betson, Matthew J Grigg, Timothy William, Nicholas M Anstey, Tsin W Yeo, Jonathan Cox, Lau Tiek Ying, Chris J Drakeley
Although asymptomatic carriage of human malaria species has been widely reported, the extent of asymptomatic, submicroscopic Plasmodium knowlesi parasitemia is unknown. In this study, samples were obtained from individuals residing in households or villages of symptomatic malaria cases with the aim of detecting submicroscopic P. knowlesi in this population. Four published molecular assays were used to confirm the presence of P. knowlesi. Latent class analysis revealed that the estimated proportion of asymptomatic individuals was 6...
March 1, 2016: Journal of Infectious Diseases
Mallika Imwong, Thuy Nhien Nguyen, Rupam Tripura, Tom J Peto, Sue J Lee, Khin Maung Lwin, Preyanan Suangkanarat, Atthanee Jeeyapant, Benchawan Vihokhern, Klanarong Wongsaen, Dao Van Hue, Le Thanh Dong, Tam-Uyen Nguyen, Yoel Lubell, Lorenz von Seidlein, Mehul Dhorda, Cholrawee Promnarate, Georges Snounou, Benoit Malleret, Laurent Rénia, Lilly Keereecharoen, Pratap Singhasivanon, Pasathorn Sirithiranont, Jem Chalk, Chea Nguon, Tran Tinh Hien, Nicholas Day, Nicholas J White, Arjen Dondorp, Francois Nosten
BACKGROUND: The importance of the submicroscopic reservoir of Plasmodium infections for malaria elimination depends on its size, which is generally considered small in low transmission settings. The precise estimation of this reservoir requires more sensitive parasite detection methods. The prevalence of asymptomatic, sub-microscopic malaria was assessed by a sensitive, high blood volume quantitative real-time polymerase chain reaction method in three countries of the Greater Mekong Sub-region...
September 30, 2015: Malaria Journal
Diego Torrús, Cristina Carranza, José Manuel Ramos, Juan Carlos Rodríguez, José Miguel Rubio, Mercedes Subirats, Thuy-Huong Ta-Tang
Current diagnosis of malaria is based on the combined and sequential use of rapid antigen detection tests (RDT) of Plasmodium and subsequent visualization of the parasite stained with Giemsa solution in a thin and thick blood smears. If an expert microscopist is not available, should always be a sensitive RDT to rule out infection by Plasmodium falciparum, output the result immediately and prepare thick smears (air dried) and thin extensions (fixed with methanol) for subsequent staining and review by an expert microscopist...
July 2015: Enfermedades Infecciosas y Microbiología Clínica
Fitsum G Tadesse, Helmi Pett, Amrish Baidjoe, Kjerstin Lanke, Lynn Grignard, Colin Sutherland, Tom Hall, Chris Drakeley, Teun Bousema, Hassen Mamo
BACKGROUND: Motivated by the success in malaria control that was documented over the last decade Ethiopia is aiming at malaria elimination by 2020 in selected districts. It is currently unknown if asymptomatic, submicroscopic malaria parasite carriage may form a hurdle to achieve elimination. The elimination effort may further be complicated by possible glucose-6 phosphate dehydrogenase (G6PD) deficiency which would hinder the use of 8-aminoquinolines in the elimination efforts. METHOD: In February 2014 a community-based cross-sectional survey was conducted in Malo, southwest Ethiopia...
2015: Malaria Journal
Marielle K Bouyou-Akotet, Marie-Louise Tshibola, Denise P Mawili-Mboumba, Julie Nzong, Noemi Bahamontes-Rosa, Gladys Tsoumbou-Bakana, Maryvonne Kombila
This study analyzed the relationship between intermittent preventive treatment with sulfadoxine-pyrimethamine (SP) (IPTp-SP), the rate of multiple resistant parasites and of submicroscopic gametocyte carriage among pregnant women at the beginning of IPTp implementation in Gabon (2005) and six years after (2011). The detection of pfdhfr and pfdhps gene mutations was performed by PCR-RFLP in Plasmodium (P.) falciparum positive samples collected from pregnant women in 2005 and 2011. Gametocytes carriage was detected by Pfs25mRNA amplification using QT-NASBA...
June 2015: Acta Parasitologica
Peter A Zimmerman, Rosalind E Howes
PURPOSE OF REVIEW: Limitations of blood smear microscopy contributed to failure of the 1950-1960s WHO Global Programme to Eliminate Malaria. All diagnostic methods encounter limits of detection (LOD) beyond which it will not be possible to identify infected individuals. When this occurs, it becomes difficult to continue evaluating progress of malaria elimination. The purpose of this review is to compare available diagnostic technologies, factors that underlie their LOD, and their potential roles related to the goal of elimination...
October 2015: Current Opinion in Infectious Diseases
Khadime Sylla, Roger Clément Kouly Tine, Magatte Ndiaye, Doudou Sow, Aïssatou Sarr, Marie Louise Tshibola Mbuyi, Ibrahima Diouf, Amy Colé Lô, Annie Abiola, Mame Cheikh Seck, Mouhamadou Ndiaye, Aïda Sadikh Badiane, Jean Louis A N'Diaye, Daouda Ndiaye, Oumar Faye, Thérèse Dieng, Yémou Dieng, Oumar Ndir, Oumar Gaye, Babacar Faye
BACKGROUND: In Senegal, a significant decrease of malaria transmission intensity has been noted the last years. Parasitaemia has become lower and, therefore, more difficult to detect by microscopy. In the context of submicroscopic parasitaemia, it has become relevant to rely on relevant malaria surveillance tools to better document malaria epidemiology in such settings. Serological markers have been proposed as an essential tool for malaria surveillance. This study aimed to evaluate the sero-epidemiological situation of Plasmodium falciparum malaria in two sentinel sites in Senegal...
2015: Malaria Journal
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