Article
Immunology
Jordache Ramjith, Manon Alkema, John Bradley, Alassane Dicko, Chris Drakeley, Will Stone, Teun Bousema
Summary: Malaria transmission depends on the presence of mature Plasmodium transmission stages. Transmission-blocking antimalarial drugs and vaccines can prevent transmission by reducing gametocyte densities or infectivity to mosquitos. This online tool helps researchers calculate the sample size to detect reductions in mosquito infection rate or infection burden.
FRONTIERS IN IMMUNOLOGY
(2022)
Article
Immunology
Manon Alkema, Isaie J. Reuling, Gerdie M. de Jong, Kjerstin Lanke, Luc E. Coffeng, Geert-Jan van Gemert, Marga van de Vegte-Bolmer, Quirijn de Mast, Reinout van Crevel, Karen Ivinson, Christian F. Ockenhouse, James S. McCarthy, Robert Sauerwein, Katharine A. Collins, Teun Bousema
Summary: The study found that the method of infection through mosquito bites or induced blood-stage malaria has a significant impact on gametocyte production, despite similar asexual parasite densities. The findings suggest that induced blood-stage malaria may be more conducive to gametocyte production compared to mosquito bites.
JOURNAL OF INFECTIOUS DISEASES
(2021)
Article
Immunology
Elamaran Meibalan, Aissata Barry, Matthew P. Gibbins, Shehu Awandu, Lisette Meerstein-Kessel, Fiona Achcar, Selina Bopp, Christopher Moxon, Amidou Diarra, Siaka Debe, Nicolas Ouedraogo, Ines Barry-Some, Emilie S. Badoum, Traore Fagnima, Kjerstin Lanke, Bronner P. Goncalves, John Bradley, Dyann Wirth, Chris Drakeley, Wamdaogo Moussa Guelbeogo, Alfred B. Tiono, Matthias Marti, Teun Bousema
Summary: The study suggests that there is no significant skin sequestration of Plasmodium falciparum gametocytes. Gametocyte densities in peripheral blood can be used to predict the potential transmission to mosquitoes, aiding in targeting and monitoring malaria elimination initiatives. Although more mosquitoes were infected when feeding directly on skin, concentrations of gametocytes in subdermal skin vasculature were not higher than in other blood compartments.
JOURNAL OF INFECTIOUS DISEASES
(2021)
Article
Immunology
Sudhir Kumar, Stefan H. I. Kappe
Summary: This article investigates the importance of differentiation of asexually replicating parasites in the sexual phase of the malaria parasite life cycle and identifies the role of PfHMGB2 in parasite development and transmission.
FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY
(2022)
Article
Immunology
Surafel K. Tebeje, Wakweya Chali, Elifaged Hailemeskel, Jordache Ramjith, Abrham Gashaw, Temesgen Ashine, Desalegn Nebret, Endashaw Esayas, Tadele Emiru, Tizita Tsegaye, Karina Teelen, Kjerstin Lanke, Eizo Takashima, Takafumi Tsuboi, Nichole D. Salinas, Niraj H. Tolia, David Narum, Chris Drakeley, Benoit Witkowski, Amelie Vantaux, Matthijs M. Jore, William J. R. Stone, Ivo S. Hansen, Fitsum G. Tadesse, Teun Bousema
Summary: This study investigated the association between antibody prevalence and the infectivity of Plasmodium vivax to mosquitoes. The results showed that antibodies against Pvs47, Pvs230, and Pvs25 were significantly associated with a reduction in mosquito infection rates. Further research can help establish causality and contribute to our understanding of P. vivax transmission and vaccine development.
FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY
(2023)
Article
Biochemistry & Molecular Biology
Luz Garcia-Longoria, Dag Ahren, Arnaud Berthomieu, Victor Kalbskopf, Ana Rivero, Olof Hellgren
Summary: This study presents the first transcriptomic analysis of the immune response of the mosquito Culex quinquefasciatus to Plasmodium relictum infection. The results reveal the important roles of Toll and Imd pathways during the critical period of parasite development. Unexpected differences in immune RNA expression patterns were also observed in infected mosquitoes compared to uninfected mosquitoes. The study expands our understanding of immune pathways and the selective pressures exerted by Plasmodium parasites on their vectors.
Article
Infectious Diseases
Harouna M. Soumare, Wamdaogo Moussa Guelbeogo, Marga van de Vegte-Bolmer, Geert-Jan van Gemert, Zongo Soumanaba, Alphonse Ouedraogo, Maurice S. Ouattara, Ahmad Abdullahi, Lamin Jadama, Muhammed M. Camara, Pa Modou Gaye, Michael Mendy, Nwakanma Davis, Alfred B. Tiono, Umberto D'Alessandro, Chris Drakeley, Teun Bousema, Marta Moreno, Katharine A. Collins
Summary: The study established the optimal method for storing and transporting gametocyte-infected blood using cultured Plasmodium falciparum gametocytes and direct membrane feeding assays in the field. Short-term and long-term temperature changes had minimal impact on the infectivity of gametocytes.
Article
Microbiology
Gunjan Arora, Andaleeb Sajid, Yu-Min Chuang, Yuemei Dong, Akash Gupta, Kristen Gambardella, Kathleen DePonte, Lionel Almeras, George Dimopolous, Erol Fikrig
Summary: Malaria is a vector-borne disease caused by Plasmodium sporozoites, and mosquito saliva proteins can influence pathogen transmission and early infection. Anopheles gambiae Sporozoite-Associated Protein (AgSAP) interacts directly with Plasmodium sporozoites, inhibits inflammatory responses, and plays a role in early infection modulation. Individuals in endemic malaria regions generate antibodies against AgSAP, suggesting its potential as a biomarker for disease prevalence and epidemiological analysis.
Article
Microbiology
Antoine Berry, Sandie Menard, Sandrine E. Nsango, Luc Abate, Didier Concordet, Majoline Tchioffo Tsapi, Xavier Iriart, Parfait H. Awono-Ambene, Benjamin Roche, Isabelle Morlais
Summary: The emergence of resistance to antimalarials has led to the exploration of novel therapies. Withdrawal of antimalarials resulted in declines in resistance markers, potentially allowing for their reintroduction. Studies show that the mosquito vector plays a key role in maintaining parasite genetic diversity and selecting minority genotypes, which may contribute to the persistence of drug-resistant alleles in malaria-endemic areas.
MICROBIOLOGY SPECTRUM
(2021)
Article
Immunology
Brian R. Omondi, Michelle K. Muthui, William Muasya, Benedict Orindi, Ramadhan S. Mwakubambanya, Teun Bousema, Chris Drakeley, Kevin Marsh, Philip Bejon, Melissa C. Kapulu
Summary: The study found that IgG responses to crude gametocyte extract may not be an independent predictor of gametocyte carriage after adjusting for AMA1 responses, but they could predict gametocyte carriage as a proxy marker of exposure to parasites. Serological responses to AMA1 or gametocyte extract may help identify individuals in populations who contribute to malaria transmission and support the implementation of transmission-blocking interventions.
FRONTIERS IN IMMUNOLOGY
(2021)
Article
Infectious Diseases
Colins O. Oduma, Sidney Ogolla, Harrysone Atieli, Bartholomew N. Ondigo, Ming-Chieh Lee, Andrew K. Githeko, Arlene E. Dent, James W. Kazura, Guiyun Yan, Cristian Koepfli
Summary: The study found that parasites increase their investment in transmission in the wet season, leading to higher gametocyte densities. However, despite the increase in gametocyte densities, parasite density remained similar across seasons. Children aged 5-15 years were found to harbor a majority of infections with moderate-to-high gametocyte densities.
BMC INFECTIOUS DISEASES
(2021)
Article
Parasitology
Bernard Mouonniba Some, Dari F. Da, Ruth McCabe, Nicaise Denis C. Djegbe, Lawata Ines Geraldine Pare, Kadidia Werme, Karine Mouline, Thierry Lefevre, Anicet Georges Ouedraogo, Thomas S. Churcher, Roch Kounbobr Dabire
Summary: This study investigated the use of insecticide spray for killing mosquitoes and determining their species and infection status using NIRS technology. The results showed that insecticide spray can be a practical alternative to chloroform in NIRS analysis, with no loss of accuracy in identifying mosquito species and infection status.
PARASITES & VECTORS
(2022)
Review
Immunology
Colins O. Oduma, Cristian Koepfli
Summary: Malaria parasites can adjust transmission investment based on the seasonality and transmission intensity of vectors, increasing the chances for transmission. Increased transmissibility of residual infections needs to be considered when designing intervention measures.
FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY
(2021)
Article
Biology
Wei Huang, Joel Vega-Rodriguez, Chritopher Kizito, Sung-Jae Cha, Marcelo Jacobs-Lorena
Summary: This study provides an in-depth assessment of transgenesis and paratransgenesis for combating malaria. The combination of these two approaches significantly reduces Plasmodium development and effectively inhibits transmission in mice.
Article
Parasitology
Domonbabele F. D. S. Hien, Prisca S. L. Pare, Amanda Cooper, Benjamin K. Koama, Edwige Guissou, Koudraogo B. Yameogo, Rakiswende S. Yerbanga, Iain W. Farrell, Jean B. Ouedraogo, Olivier Gnankine, Rickard Ignell, Anna Cohuet, Roch K. Dabire, Philip C. Stevenson, Thierry Lefevre
Summary: The study shows that certain plant compounds in nectar can affect the lifespan of mosquitoes and the infection rate of parasites, but the effects of ricinine at different concentrations vary between the two species of mosquitoes.
PARASITES & VECTORS
(2021)
Article
Immunology
Kasia Stepniewska, Georgina S. Humphreys, Bronner P. Goncalves, Elaine Craig, Roly Gosling, Philippe J. Guerin, Ric N. Price, Karen Barnes, Jaishree Raman, Menno R. Smit, Umberto D'Alessandro, Will J. R. Stone, Anders Bjorkman, Aaron M. Samuels, Maria Arroyo-Arroyo, Guido J. H. Bastiaens, Joelle M. Brown, Alassane Dicko, Badria B. El-Sayed, Salah-Eldin G. Elzaki, Alice C. Eziefula, Simon Kariuki, Titus K. Kwambai, Amanda E. Maestre, Andreas Martensson, Dominic Mosha, Richard O. Mwaiswelo, Billy E. Ngasala, Joseph Okebe, Michelle E. Roh, Patrick Sawa, Alfred B. Tiono, Ingrid Chen, Chris J. Drakeley, Teun Bousema
Summary: A meta-analysis of individual patients was conducted to assess the gametocytocidal and transmission-blocking activities of single-dose primaquine. The results showed that primaquine, when administered with artemisinin-based combination therapies, can effectively reduce the gametocyte carriage rate after 7 and 14 days, especially in patients with existing gametocytes at the start of treatment. Furthermore, the combination of primaquine and artemether-lumefantrine showed a faster decline in gametocyte carriage compared to the combination with dihydroartemisinin-piperaquine. Additionally, the addition of 0.25 mg/kg primaquine can nearly completely prevent transmission to mosquitoes.
JOURNAL OF INFECTIOUS DISEASES
(2022)
Article
Infectious Diseases
Harouna M. Soumare, Wamdaogo Moussa Guelbeogo, Marga van de Vegte-Bolmer, Geert-Jan van Gemert, Zongo Soumanaba, Alphonse Ouedraogo, Maurice S. Ouattara, Ahmad Abdullahi, Lamin Jadama, Muhammed M. Camara, Pa Modou Gaye, Michael Mendy, Nwakanma Davis, Alfred B. Tiono, Umberto D'Alessandro, Chris Drakeley, Teun Bousema, Marta Moreno, Katharine A. Collins
Summary: The study established the optimal method for storing and transporting gametocyte-infected blood using cultured Plasmodium falciparum gametocytes and direct membrane feeding assays in the field. Short-term and long-term temperature changes had minimal impact on the infectivity of gametocytes.
Article
Multidisciplinary Sciences
Aissata Barry, John Bradley, Will Stone, Moussa W. Guelbeogo, Kjerstin Lanke, Alphonse Ouedraogo, Issiaka Soulama, Issa Nebie, Samuel S. Serme, Lynn Grignard, Catriona Patterson, Lindsey Wu, Jessica J. Briggs, Owen Janson, Shehu S. Awandu, Mireille Ouedraogo, Casimire W. Tarama, Desire Kargougou, Soumanaba Zongo, Sodiomon B. Sirima, Matthias Marti, Chris Drakeley, Alfred B. Tiono, Teun Bousema
Summary: The study found that in children in Burkina Faso, chronic infections of Plasmodium falciparum have higher gametocyte production and mosquito infectivity. Incident infections typically require treatment before reaching a sufficient density of mature gametocytes to infect mosquitoes.
NATURE COMMUNICATIONS
(2021)
Article
Infectious Diseases
William Stone, Almahamoudou Mahamar, Koualy Sanogo, Youssouf Sinaba, Sidi M. Niambele, Adama Sacko, Sekouba Keita, Ahamadou Youssouf, Makonon Diallo, Harouna M. Soumare, Harparkash Kaur, Kjerstin Lanke, Rob Ter Heine, John Bradley, Djibrilla Issiaka, Halimatou Diawara, Sekou F. Traore, Teun Bousema, Chris Drakeley, Alassane Dicko
Summary: The addition of low-dose primaquine to dihydroartemisinin-piperaquine and pyronaridine-artesunate was found to effectively block Plasmodium falciparum transmission.
Article
Immunology
Katharine A. Collins, Sukai Ceesay, Sainabou Drammeh, Fatou K. Jaiteh, Marc-Antoine Guery, Kjerstin Lanke, Lynn Grignard, Will Stone, David J. Conway, Umberto D'Alessandro, Teun Bousema, Antoine Claessens
Summary: In areas with seasonal Plasmodium falciparum malaria, a reservoir of blood-stage infection during the dry season is crucial for initiating transmission in the wet season. A study in The Gambia found that a significant proportion of individuals infected at the end of the wet season continued to have detectable infections until the end of the dry season. These persistent infections were more likely to have higher parasite densities and be multiclonal compared to short-lived infections. Screening and treating asymptomatic infections during the dry season may help reduce the reservoir of malaria responsible for transmission in the wet season.
JOURNAL OF INFECTIOUS DISEASES
(2022)
Article
Immunology
Jordache Ramjith, Manon Alkema, John Bradley, Alassane Dicko, Chris Drakeley, Will Stone, Teun Bousema
Summary: Malaria transmission depends on the presence of mature Plasmodium transmission stages. Transmission-blocking antimalarial drugs and vaccines can prevent transmission by reducing gametocyte densities or infectivity to mosquitos. This online tool helps researchers calculate the sample size to detect reductions in mosquito infection rate or infection burden.
FRONTIERS IN IMMUNOLOGY
(2022)
Article
Infectious Diseases
Will Stone, Almahamoudou Mahamar, Merel J. Smit, Koualy Sanogo, Youssouf Sinaba, Sidi M. Niambele, Adama Sacko, Sekouba Keita, Oumar M. Dicko, Makonon Diallo, Seydina O. Maguiraga, Siaka Samake, Oumar Attaher, Kjerstin Lanke, Rob Ter Heine, John Bradley, Matthew B. B. McCall, Djibrilla Issiaka, Sekou F. Traore, Teun Bousema, Chris Drakeley, Alassane Dicko
Summary: By combining with dihydroartemisinin-piperaquine, three single low doses of tafenoquine can effectively reduce the infection and transmission rates of Plasmodium falciparum. Tafenoquine is well tolerated and can accelerate the clearance of gametocytes.
Article
Immunology
Roos M. de Jong, Manon Alkema, Tate Oulton, Elin Dumont, Karina Teelen, Rie Nakajima, Rafael Ramiro de Assis, Kathleen W. Dantzler Press, Priscilla Ngotho, Kevin K. A. Tetteh, Phil Felgner, Matthias Marti, Katharine A. Collins, Chris Drakeley, Teun Bousema, Will J. R. Stone
Summary: This study investigates the antibody responses to sexual stage antigens in individuals infected with P. falciparum. The results show that even after exposure to relatively low gametocyte densities, a significant anti-sexual stage humoral response is induced in malaria-naive individuals. The study identifies novel antigens associated with gametocyte exposure, which can be used for surveillance of the malaria infectious reservoir and support vaccine development.
FRONTIERS IN IMMUNOLOGY
(2022)
Article
Immunology
Roos M. de Jong, Susheel K. Singh, Karina Teelen, Marga van de Vegte-Bolmer, Geert-Jan van Gemert, Will J. R. Stone, Emily Locke, Jordan Plieskatt, Michael Theisen, Teun Bousema, Matthijs M. Jore
Summary: Researchers analyzed sera from naturally exposed individuals and found that the presence and/or intensity of antibodies against 12 novel putative surface expressed gametocyte antigens was associated with transmission reducing activity. Protein fragments of these antigens were successfully designed and expressed in different cells. All tested antigens were recognized by antibodies from individuals living in malaria-endemic areas and induced antigen-specific antibody responses in mice. However, none of these antigens induced an antibody response that reduced parasite development in the mosquito midgut.
FRONTIERS IN IMMUNOLOGY
(2022)
Review
Medicine, General & Internal
Kasia Stepniewska, Elizabeth N. Allen, Georgina S. Humphreys, Eugenie Poirot, Elaine Craig, Kalynn Kennon, Daniel Yilma, Teun Bousema, Philippe J. Guerin, Nicholas J. White, Ric N. Price, Jaishree Raman, Andreas Martensson, Richard O. Mwaiswelo, Germana Bancone, Guido J. H. Bastiaens, Anders Bjorkman, Joelle M. Brown, Umberto D'Alessandro, Alassane A. Dicko, Badria El-Sayed, Salah-Eldin Elzaki, Alice C. Eziefula, Bronner P. Goncalves, Muzamil Mahdi Abdel Hamid, Akira Kaneko, Simon Kariuki, Wasif Khan, Titus K. Kwambai, Benedikt Ley, Billy E. Ngasala, Francois Nosten, Joseph Okebe, Aaron M. Samuels, Menno R. Smit, Will J. R. Stone, Inge Sutanto, Feiko Ter Kuile, Roger C. Tine, Alfred B. Tiono, Chris J. Drakeley, Roly Gosling, Andy Stergachis, Karen Barnes, Ingrid Chen
Summary: This study analyzed the side effects of primaquine for the treatment of falciparum malaria and found that the use of 0.25 mg/kg primaquine as a gametocytocide is safe and effective, even in individuals with G6PD deficiency.
Article
Multidisciplinary Sciences
Tate Oulton, Joshua Obiero, Isabel Rodriguez, Isaac Ssewanyana, Rebecca A. Dabbs, Christine M. Bachman, Bryan Greenhouse, Chris Drakeley, Phil L. Felgner, Will Stone, Kevin K. A. Tetteh
Summary: This study compared antigen-matched protein targets from an IVTT system and purified recombinant system. The results showed that purified recombinant proteins induced stronger antibody responses compared to IVTT proteins. There was no clear correlation between responses from targets produced in different expression systems, but responses between amino acid sequence-matched targets from each expression system were more closely correlated. Therefore, protein microarrays produced using either method can be confidently used in a context dependent manner, but caution should be taken when comparing data derived from contrasting approaches.
Article
Immunology
Kazutoyo Miura, Thao P. Pham, Shwu-Maan Lee, Jordan Plieskatt, Ababacar Diouf, Issaka Sagara, Camila H. Coelho, Patrick E. Duffy, Yimin Wu, Carole A. Long
Summary: Monitoring the integrity of recombinant proteins is critical during the development of subunit vaccines. This study developed a sandwich ELISA-based in vitro potency assay, called the Antigen Integrity Assay (AIA), to monitor the potency of Pfs230 protein. The AIA demonstrated excellent precision, sensitivity, and high throughput, making it a useful tool for future subunit vaccine development.
Article
Infectious Diseases
Tate Oulton, Almahamoudou Mahamar, Koualy Sanogo, Makonon Diallo, Ahamadou Youssouf, Sidi M. M. Niambele, Siaka Samake, Sekouba Keita, Youssouf Sinaba, Adama Sacko, Sekou F. F. Traore, Kjerstin Lanke, Katharine A. A. Collins, John Bradley, Chris Drakeley, Will J. R. Stone, Alassane Dicko
Summary: This study assessed the detectability of HRP-2 in periods of post-treatment residual gametocytaemia. The results suggest that surviving sexual stage parasites after standard ACT treatment do not contribute to the persistence of HRP-2 antigenaemia and have little impact on RDT results.
Article
Immunology
Surafel K. Tebeje, Wakweya Chali, Elifaged Hailemeskel, Jordache Ramjith, Abrham Gashaw, Temesgen Ashine, Desalegn Nebret, Endashaw Esayas, Tadele Emiru, Tizita Tsegaye, Karina Teelen, Kjerstin Lanke, Eizo Takashima, Takafumi Tsuboi, Nichole D. Salinas, Niraj H. Tolia, David Narum, Chris Drakeley, Benoit Witkowski, Amelie Vantaux, Matthijs M. Jore, William J. R. Stone, Ivo S. Hansen, Fitsum G. Tadesse, Teun Bousema
Summary: This study investigated the association between antibody prevalence and the infectivity of Plasmodium vivax to mosquitoes. The results showed that antibodies against Pvs47, Pvs230, and Pvs25 were significantly associated with a reduction in mosquito infection rates. Further research can help establish causality and contribute to our understanding of P. vivax transmission and vaccine development.
FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY
(2023)
Article
Multidisciplinary Sciences
Leen N. N. Vanheer, Almahamoudou Mahamar, Emilia Manko, Sidi M. M. Niambele, Koualy Sanogo, Ahamadou Youssouf, Adama Dembele, Makonon Diallo, Seydina O. O. Maguiraga, Jody Phelan, Ashley Osborne, Anton Spadar, Merel J. J. Smit, Teun Bousema, Chris Drakeley, Taane G. G. Clark, William Stone, Alassane Dicko, Susana Campino
Summary: Sequence analysis of Plasmodium falciparum parasites in asymptomatic individuals in South-Western Mali reveals an increase in genetic variation and drug resistance frequencies. This is important for monitoring the emergence and spread of drug-resistant parasites, informing malaria control efforts in Mali and worldwide.
SCIENTIFIC REPORTS
(2023)