Teun Bousema

Teun Bousema
Radboud University Medical Centre (Radboudumc) · Department of Medical Microbiology

PhD

About

602
Publications
101,228
Reads
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18,475
Citations
Introduction
Teun Bousema currently works at the Department of Medical Microbiology, Radboud University Medical Centre (Radboudumc). Teun does research in malaria epidemiology with a specific focus on malaria transmission and gametocyte biology.
Additional affiliations
July 2015 - December 2015
Radboud University Medical Centre (Radboudumc)
Position
  • Professor (Associate)
January 2012 - present
Radboud University Medical Centre (Radboudumc)
Position
  • Lecturer
January 2012 - September 2014
Radboud University
Position
  • Lecturer
Description
  • 2nd active affiliation

Publications

Publications (602)
Preprint
It is currently unknown whether all Plasmodium falciparum infected mosquitoes are equally infectious. We assessed sporogonic development using cultured gametocytes in the Netherlands and natural infections in Burkina Faso. We quantified the number of sporozoites expelled into artificial skin in relation to intact oocysts, ruptured oocysts, and resi...
Preprint
It is currently unknown whether all Plasmodium falciparum infected mosquitoes are equally infectious. We assessed sporogonic development using cultured gametocytes in the Netherlands and natural infections in Burkina Faso. We quantified the number of sporozoites expelled into artificial skin in relation to intact oocysts, ruptured oocysts, and resi...
Preprint
Circulating sexual stages of Plasmodium falciparum (Pf) can be transmitted from humans to mosquitoes, thereby furthering the spread of malaria in the population. It is well established that antibodies (Abs) can efficiently block parasite transmission. In search for naturally acquired Ab targets on sexual stages, we established an efficient method f...
Article
Full-text available
Anopheles stephensi, an Asian malaria vector, continues to expand across Africa. The vector is now firmly established in urban settings in the Horn of Africa. Its presence in areas where malaria resurged suggested a possible role in causing malaria outbreaks. Using a prospective case control design, we investigated the role of An. stephensi in tran...
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Background. Chronic carriage of asymptomatic low-density Plasmodium falciparum parasitaemia in the dry season may support maintenance of acquired immunity that protects against clinical malaria. However, the relationship between chronic low-density infections and subsequent risk of clinical malaria episodes remains unclear. Methods. In a 2-years st...
Preprint
Full-text available
It is currently unknown whether all Plasmodium falciparum infected mosquitoes are equally infectious. We assessed sporogonic development using cultured gametocytes in the Netherlands and natural infections in Burkina Faso. We quantified the number of sporozoites expelled into artificial skin in relation to intact oocysts, ruptured oocysts, and resi...
Preprint
Full-text available
In 2022 the WHO recommended the discretionary expansion of the eligible age range for seasonal malaria chemoprevention to children older than 4 years. Older children are at lower risk of clinical disease and severe malaria so there has been uncertainty about the cost benefit for national control programmes. However a growing body of laboratory rese...
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Antimalarial drugs that can block the transmission of Plasmodium gametocytes to mosquito vectors would be highly beneficial for malaria elimination efforts. Identifying transmission-blocking drugs currently relies on evaluation of their activity against gametocyte-producing laboratory parasite strains and would benefit from a testing pipeline with...
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Sequence analysis of Plasmodium falciparum parasites is informative in ensuring sustained success of malaria control programmes. Whole-genome sequencing technologies provide insights into the epidemiology and genome-wide variation of P. falciparum populations and can characterise geographical as well as temporal changes. This is particularly import...
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Full-text available
Malaria transmission depends on the presence of Plasmodium gametocytes that are the only parasite life stage that can infect mosquitoes. Gametocyte production varies between infections and over the course of infections. Infection duration is highly important for gametocyte production but poorly quantified. Between 2017 and 2019 an all-age cohort of...
Preprint
Full-text available
Anopheles stephensi , an Asian urban malaria vector, continues to expand across Africa. We investigated the role of An. stephensi in malaria transmission following a dry season outbreak in Dire Dawa, Ethiopia, from April to July 2022, using a prospective case control design. Plasmodium falciparum microscopy-positive febrile patients (n = 101) and m...
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Transmission-blocking interventions can play an important role in combatting malaria worldwide. Recently, a highly potent Plasmodium falciparum transmission-blocking monoclonal antibody (TB31F) was demonstrated to be safe and efficacious in malaria-naive volunteers. Here we predict the potential public health impact of large-scale implementation of...
Article
Full-text available
Since its first detection in 2012 in Djibouti, Anopheles stephensi has invaded and established in the Horn of Africa, and more recently Nigeria. The expansion of this vector poses a significant threat to malaria control and elimination efforts. Integrated vector management is the primary strategy used to interrupt disease transmission; however, gro...
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Full-text available
The malaria parasite life cycle includes asexual replication in human blood, with a proportion of parasites differentiating to gametocytes required for transmission to mosquitoes. Commitment to differentiate into gametocytes, which is marked by activation of the parasite transcription factor ap2-g, is known to be influenced by host factors but a co...
Preprint
Full-text available
Malaria is transmitted when Anopheline mosquitoes ingest Plasmodium parasites during blood-feeding. Artificial feeding assays allow mosquitoes to take up blood from membrane feeders, and are widely used to study malaria transmission. These assays require large quantities of mosquitoes; insectaries optimize their rearing procedures to generate high...
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Malaria transmission-blocking vaccines (TBVs) aim to induce antibodies that interrupt malaria parasite development in the mosquito, thereby blocking onward transmission, and provide a much-needed tool for malaria control and elimination. The parasite surface protein Pfs48/45 is a leading TBV candidate. Here, we isolated and characterized a panel of...
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Pfs230 is essential for Plasmodium falciparum transmission to mosquitoes and is the protein targeted by the most advanced malaria-transmission-blocking vaccine candidate. Prior understanding of functional epitopes on Pfs230 is based on two monoclonal antibodies (mAbs) with moderate transmission-reducing activity (TRA), elicited from subunit immuniz...
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Background: Asymptomatic Plasmodium carriers form the majority of malaria-infected individuals in most endemic areas. A proportion of these asymptomatically infected individuals carry gametocytes, the transmissible stages of malaria parasites, that sustain human to mosquito transmission. Few studies examine gametocytaemia in asymptomatic school chi...
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Naturally acquired antibodies may reduce the transmission of Plasmodium gametocytes to mosquitoes. Here, we investigated associations between antibody prevalence and P. vivax infectivity to mosquitoes. A total of 368 microscopy confirmed P. vivax symptomatic patients were passively recruited from health centers in Ethiopia and supplemented with 56...
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We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network. It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented. For the first time we include dried blood spot sample...
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Background Glass membrane feeders are used in malaria research for artificial blood feeding. This study investigates the use of Hemotek membrane feeders as a standardized alternative feeding system. Methods Hemotek feeders were compared with glass feeders by assessing mosquito feeding rate, imbibed blood meal volume and Plasmodium falciparum infec...
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Tororo District, in Eastern Uganda, experienced a dramatic decline in malaria burden starting in 2014 following the implementation of indoor residual spraying of insecticide (IRS) in the setting of repeated long-lasting insecticide treated nets (LLINs) distribution campaigns. However, in 2020 malaria began to resurge in Tororo following a change in...
Preprint
Full-text available
Since its first detection in 2012 in Djibouti, Anopheles stephensi has invaded and established itself in the Horn of Africa and most recently in Nigeria and Yemen. The expansion of this vector poses a significant threat to malaria control and eliminations efforts. Integrated vector management is the primary strategy used to interrupt disease transm...
Article
Full-text available
Background Plasmodium falciparum malaria is associated with anaemia-related morbidity, attributable to host, parasite and drug factors. We quantified the haematological response following treatment of uncomplicated P. falciparum malaria to identify the factors associated with malarial anaemia. Methods Individual patient data from eligible antimala...
Preprint
Full-text available
The malaria parasite life cycle includes asexual replication in human blood, with a proportion of parasites differentiating to gametocytes required for transmission to mosquitoes. Commitment to differentiate into gametocytes, which is marked by activation of the parasite transcription factor ap2-g, is known to be influenced by host factors but a co...
Article
Full-text available
Background Vector control interventions in sub-Saharan Africa rely on insecticide-treated nets and indoor residual spraying. Insecticide resistance, poor coverage of interventions, poor quality nets and changes in vector behavior threaten the effectiveness of these interventions and, consequently, alternative tools are needed. Mosquitoes die after...
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The observed induction time from an infection to an event of interest is often double-interval-censored and moreover, often prevented from being observed by the clearance of the infection (a competing risk). Double-interval-censoring and the presence of competing risks complicate the statistical analysis extremely and are therefore usually ignored...
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The complement system is considered the first line of defense against pathogens. Hijacking complement regulators from blood is a common evasion tactic of pathogens to inhibit complement activation on their surfaces. Here, we report hijacking of the complement C4b-binding protein (C4bp), the regulator of the classical and lectin pathways of compleme...
Preprint
Full-text available
Malaria transmission depends on the presence of Plasmodium gametocytes that are the only parasite life stage that can infect mosquitoes. Gametocyte production varies between infections and over the course of infections. Infection duration is highly important for gametocyte production but poorly quantified. Between 2017–2019 an all-age cohort of ind...
Article
Full-text available
The Program for Resistance, Immunology, Surveillance, and Modeling of Malaria (PRISM) has been conducting malaria research in Uganda since 2010 to improve the understanding of the disease and measure the impact of population-level control interventions in the country. Here, we will summarize key research findings from a series of studies addressing...
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Background In 2012, the World Health Organization (WHO) recommended single low-dose (SLD, 0.25 mg/kg) primaquine to be added as a Plasmodium (P.) falciparum gametocytocide to artemisinin-based combination therapy (ACT) without glucose-6-phosphate dehydrogenase (G6PD) testing, to accelerate malaria elimination efforts and avoid the spread of artemis...
Preprint
Full-text available
Transmission-blocking interventions can play an important role in combatting malaria worldwide. Recently, a highly potent Plasmodium falciparum transmission-blocking monoclonal antibody (TB31F) was demonstrated to be safe and efficacious in malaria-naïve volunteers. Here we determine what dose would be required to obtain effective transmission redu...
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Full-text available
To the Editor—We have read with great interest the article by Andagalu and colleagues on the important topic of Plasmodium transmission in relation to antimalarial treatment success [1]. We also have some concerns about data presentation and the robustness of several findings. First, we advocate a more stringent definition of treatment failure or “...
Preprint
Malaria transmission depends on the presence of Plasmodium gametocytes that are the only parasite life stage that can infect mosquitoes. Gametocyte production varies between infections and over the course of infections. Infection duration is influenced by host and parasite characteristics, and is highly important for gametocyte production but poorl...
Article
Background Malaria elimination requires interruption of the highly efficient transmission of Plasmodium parasites by mosquitoes. TB31F is a humanised monoclonal antibody that binds the gamete surface protein Pfs48/45 and inhibits fertilisation, thereby preventing further parasite development in the mosquito midgut and onward transmission. We aimed...
Preprint
BACKGROUND Malaria gains have stagnated since 2015, threatened further by increasing resistance to insecticides and antimalarials. Improvement in malaria control necessitates a multi-pronged strategy which includes the development of novel tools. One such tool is the mass drug administration (MDA) with endectocides, primarily ivermectin, which has...
Article
Full-text available
Background: The gains made against malaria have stagnated since 2015, threatened further by increasing resistance to insecticides and antimalarials. Improvement in malaria control necessitates a multipronged strategy, which includes the development of novel tools. One such tool is mass drug administration (MDA) with endectocides, primarily ivermec...
Article
Full-text available
Individuals infected with P. falciparum develop antibody responses to intra-erythrocytic gametocyte proteins and exported gametocyte proteins present on the surface of infected erythrocytes. However, there is currently limited knowledge on the immunogenicity of gametocyte antigens and the specificity of gametocyte-induced antibody responses. In thi...
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Decreased platelet count is an early phenomenon in asexual Plasmodium falciparum parasitemia, but its association with acute or long-term functional changes in platelets and coagulation is unknown. Moreover, the impact of gametocytemia on platelets and coagulation remains unclear. We investigated the changes in platelet number and function during e...
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Vector control strategies are among the most effective measures to combat mosquito-borne diseases, such as malaria. These strategies work by altering the mosquito age structure through increased mortality of the older female mosquitoes that transmit pathogens. However, methods to monitor changes to mosquito age structure are currently inadequate fo...
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Full-text available
Malaria transmission depends on the presence of mature Plasmodium transmission stages (gametocytes) that may render blood-feeding Anopheles mosquitos infectious. Transmission-blocking antimalarial drugs and vaccines can prevent transmission by reducing gametocyte densities or infectivity to mosquitos. Mosquito infection outcomes are thereby informa...
Article
Full-text available
Malaria transmission blocking vaccines (TBV) aim to induce antibodies that can interrupt Plasmodium falciparum development in the mosquito midgut and thereby prevent onward malaria transmission. A limited number of TBV candidates have been identified and only three (Pfs25, Pfs230 and Pfs48/45) have entered clinical testing. While one of these candi...
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Full-text available
Knowledge about contagiousness is key to accurate management of hospitalized COVID-19 patients. Epidemiological studies suggest that in addition to transmission through droplets, aerogenic SARS-CoV-2 transmission contributes to the spread of infection. However, the presence of virus in exhaled air has not yet been sufficiently demonstrated. In pand...
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Achieving malaria elimination requires a better understanding of the transmissibility of human infections in different transmission settings. This study aimed to characterize the human infectious reservoir in a high endemicity setting in eastern Uganda, using gametocyte quantification and mosquito feeding assays. In asymptomatic infections, gametoc...
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Background Sub-Saharan Africa has seen substantial reductions in cases and deaths due to malaria over the past two decades. While this reduction is primarily due to an increasing expansion of interventions, urbanisation has played its part as urban areas typically experience substantially less malaria transmission than rural areas. However, this ma...
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Background In areas where Plasmodium falciparum malaria is seasonal, a dry season reservoir of blood-stage infection is essential for initiating transmission during the following wet season. Methods In The Gambia, a cohort of 42 individuals with qPCR positive P. falciparum infections at the end of the transmission season (December) were followed m...
Preprint
Full-text available
Introduction: Tororo District, in Eastern Uganda, experienced a dramatic decline in malaria burden following the implementation of indoor residual spraying of insecticide (IRS) in 2014; the adjacent Busia District did not receive IRS. Data from areas near the margins of IRS coverage are limited. In this study, measures of malaria transmission, infe...
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Full-text available
House construction is rapidly modernizing across Africa but the potential benefits for human health are poorly understood. We hypothesised that improvements to housing would be associated with reductions in malaria, acute respiratory infection (ARI) and gastrointestinal illness in an area of low malaria endemicity in Uganda. Data were analysed from...
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Artemisinin-based combination therapies (ACT) are the frontline treatments against malaria worldwide. Recently the use of traditional infusions from Artemisia annua (from which artemisinin is obtained) or Artemisia afra (lacking artemisinin) has been controversially advocated. Such unregulated plant-based remedies are strongly discouraged as they m...
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Background Fever and inflammation are a hallmark of clinical Plasmodium falciparum (Pf) malaria induced by circulating asexual parasites. Although clinical manifestations of inflammation are associated with parasite density, this relationship is influenced by a complex network of immune-modulating factors of both human and parasite origin. Methods...
Article
Background Tafenoquine was recently approved as a prophylaxis and radical cure for Plasmodium vivax infection, but its Plasmodium falciparum transmission-blocking efficacy is unclear. We aimed to establish the efficacy and safety of three single low doses of tafenoquine in combination with dihydroartemisinin–piperaquine for reducing gametocyte dens...
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Full-text available
During co-evolution Plasmodium parasites and vertebrates went through a process of selection resulting in defined and preferred parasite-host combinations. As such, Plasmodium falciparum (Pf ) sporozoites can infect human hepatocytes while seemingly incompatible with host cellular machinery of other species. The compatibility between parasite invas...
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Sporozoite-based approaches currently represent the most effective vaccine strategies for induction of sterile protection against Plasmodium falciparum (Pf) malaria. Clinical development of sub-unit vaccines is almost exclusively centered around the Circum-sporozoite Protein (CSP) an abundantly expressed protein on the sporozoite membrane. Anti-CSP...
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Objective To examine how global health institutions are reducing the greenhouse gas emissions from their own operations and analyze the facilitators and barriers to achieving decarbonization goals. Methods We reviewed the sustainability goals and implementation plans of 10 global health universities from the ʻTropEdʼ network. We systematically col...
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Clinical studies have shown that adding a single 0.25mg base/kg dose of primaquine to standard antimalarial regimens rapidly sterilises Plasmodium falciparum gametocytes. However, the mechanism of action and overall impact on malaria transmission is still unknown. Using data from 81 adult Malians with P. falciparum gametocytaemia who received the s...
Article
Background Although the malaria burden has substantially decreased in sub-Saharan Africa, progress has stalled. We assessed whether mass administration of ivermectin (a mosquitocidal drug) and dihydroartemisinin–piperaquine (an antimalarial treatment) reduces malaria in The Gambia, an area with high coverage of standard control interventions. Meth...