Studies on Madariaga virus (MADV), a potential emerging threat
MADV, an underexplored member of the eastern equine encephalitis virus complex, poses a health threat to humans and equines. In 2019, we isolated MADV from horses that died of neurological disease in Northeast Brazil. We are currently conducting various studies to better understand its transmission cycle, pathogenicity, and other aspects. These projects involve a variety of in vivo (e.g., mosquitoes, mice, large animals) and in vitro (e.g., brain organoids) study models and ultimately aim at contributing to preparedness efforts.
MADV circulates in numerous countries of Latin America and is a potential emerging arbovirus
(Fig. published in Magalhaes et al., VBZD 2023)
There are many unknowns about MADV, including the vectors and vertebrate hosts involved in transmission cycles
(Fig. published in Magalhaes et al., VBZD 2023)
Exploring epidemiological aspects of Zika, dengue and chikungunya viruses within human cohorts
We have been conducting research in Northeast Brazil with human cohorts to study various epidemiological aspects of Zika, dengue, and chikungunya viruses. Our research has involved detecting ongoing outbreaks, exploring the role of sexual transmission in Zika epidemiology, and assessing humoral immunity profiles against arboviruses over time. These studies aim to help us better understand the spatiotemporal variation in arboviral disease epidemiology.
Hotspots of Zika virus and chikungunya virus infections during outbreaks in a region of Northeast Brazil in 2015-2016
(Fig. published in Magalhaes et al., PNTD 2017)
The relevance of sexual transmission of Zika virus was assessed through a retrospective cohort study conducted in households in Northeast Brazil, and in a population-based serosurvey analysis
(Magalhaes et al., JID 2021, Magalhaes et al., EID 2025)
Field simulations: mosquito biology and arbovirus transmission
From a mosquito biology standpoint, various scenarios can occur in the field when arboviruses are circulating within a geographic area. For instance, female mosquitoes can ingest different arboviruses from different hosts, as well as antibodies and even medicine taken by humans. In the laboratory, we simulate these scenarios to assess virus transmission outcomes. This data can contribute to our understanding of disease epidemiology and may be used for modeling studies on arboviral disease transmission.
The biology of mosquito vectors must be considered in the epidemiology and transmission patterns of arboviruses. In our laboratory, we simulate various field scenarios and incorporate mosquito biology features in the experiments to evaluate arbovirus transmission outcomes.
2026
Steinberg Z, Rosenberger KD, Morales I, Tami A, Bethencourt SE, Magalhaes T, Marques ETA, Marón GM, Sandoval EP, Benevides BS, Caprara A, Wills B, Alexander N, Jaenisch T, and the IDAMS clinical study group. Differentiation between acute stage arboviral illness in Latin America using algorithms including clinical signs and symptoms, routine laboratory values, and serology (accepted). Am J Trop Med Hyg.
Carvalho-Leandro D, Ferreira FC, Fernandez-Santos N, Sames IV WJ, Tian Y, Ndeffo-Mbah ML, Costa EA, Turell MJ, Hamer GL, Magalhaes T. Transmission potential of Culex and Aedes species for Madariaga virus, a member of the eastern equine encephalitis virus complex. PLOS Negl Trop Dis. 2026 12;20(5).
doi: 10.1371/journal.pntd.0013516
Abdi AA, Almeida R, Harris T, Magalhaes T, Juarez JG, Hamer GL. Forgotten in the tropics: Neglect of Culex mosquitoes in malaria and dengue-endemic regions (In press). Parasites & Vectors.
S. Gupta, R. Sharma, A. E. Williams, I. Sanchez-Vargas, N. H. Rose, C. Zhang, et al. Small RNA genomics of Aedes aegypti mosquitoes discovers infectious viruses that trigger an RNA interference response. Nat Comm. 2026 17(1); 1–9.
doi: 10.1038/s41467-026-71964-1
Abdi AA, Juarez JG, Harris T, Magalhaes T, Hamer GL. Systematic review of Aedes aegypti control trials suggests publication bias related to author disclosure of conflicts of interest. PLOS Negl Trop Dis. Jan 2026.
2025
Some AF, Some A, Sougue E, Ouedraogo COW, Da O, Rodrigue Dah S, Nikiema F, Magalhaes T, et al. Safety and efficacy of repeat ivermectin mass drug administrations for malaria control (RIMDAMAL II): a phase 3, double-blind, placebo-controlled, cluster-randomised, parallel-group trial. Lancet Infect Dis. Epub Published online February 4, 2025.
doi: 10.1016/S1473-3099(24)00751-5
Oliveira APC, Vieira DA, Cardoso CW, Magalhaes T, Anjos RO, Reis E, Santos KOB and Ribeiro GS (2025). Work ability during the COVID-19 pandemic: A cross-sectional study in a low-income urban setting in Brazil. PLOS One. 2025 20(7).
2024
Magalhaes T*, Coelho FC*, Souza WV, Viana IFT, Jaenisch T, Marques ETA, Foy BD, Braga C. Effect of Sexual Partnerships on Zika Virus Transmission in Virus-Endemic Region, Northeast Brazil. Emerg Infect Dis. 2024 Dec;30(12). *Equal contribution.
Magalhaes T, Hamer GL, de Carvalho-Leandro D, Ribeiro VML, Turell MJ. Uncertainties Surrounding Madariaga Virus, a Member of the Eastern Equine Encephalitis Virus Complex. Vector Borne Zoonotic Dis. 2024 May 8.
Castanha PMS, McEnaney PJ, Park Y, Bouwer A, Chaves EJF, Lins RD, Paciaroni NG, Dickson P, Carlson G, Cordeiro MT, Magalhaes T, Craigo J, Marques ETA, Kodadek T, Burke DS. Identification and characterization of a nonbiological small-molecular mimic of a Zika virus conformational neutralizing epitope. Proc Natl Acad Sci U S A. 2024 May 21;121(21).
Magalhaes T, Barreto A, Mesquita-Silva J, Serravalle KML, Valente de Andrade M, Gomes RCL, Nazare RJ, Calado RMGA, Ribeiro GS, Kitron U. Tailoring a One Health course for an established non-One Health graduate program in Brazil. Front Trop Dis. 2024 January 5.
doi: 10.3389/fitd.2023.1317092
Gomez G, Hufstedler H, Montenegro Morales C, Roell Y, Lozano-Parra A, Tami A, Magalhaes T, Marques ETA, Balmaseda A, Calvet G, Harris E, Brasil P, Herrera V, Villar L, Maxwell L, Jaenisch T, ReCo DIDAhsg. Pooled Cohort Profile: ReCoDID Consortium's Harmonized Acute Febrile Illness Arbovirus Meta-Cohort. JMIR Public Health Surveill. 2024;10:e54281.
2023
Magalhaes T, Portilho MM, Moreira PSS, Marinho ML, Dias WP, Gonçalves NM, Rodrigues OAS, Montes J, Reis L, Jesus DF, Silva TO, Dultra LS, Nery JS, Ribeiro GS. Validation of the use of dried blood spots in a chikungunya virus IgG serological assay. J Immunol Methods. 2023 Nov; 522: 113571.
Rosenberger KD, Phung Khanh L, Tobian F, Chanpheaktra N, Kumar V, et al. Early diagnostic indicators of dengue versus other febrile illnesses in Asia and Latin America (IDAMS study): a multicentre, prospective, observational study. Lancet Glob Health. 2023;11(3):e361-e72.
doi: 10.1016/S2214-109X(22)00514-9
Foy BD, Magalhaes T, Some A, Gray L, Rao S, Sougue E, Jackson CL, Kittleson J, Slater HC, Bousema T, Ollo D, Coulidiaty G, Colt M, Wade M, Richards K, Fabrice Some A, Dabire RK, Parikh S. Repeat Ivermectin Mass Drug Administrations for Malaria Control II: a double-blind, cluster-randomized control trial for integrated control of malaria. Protocol for the RIMDAMAL II Trial. JMIR Research Protocols 2023; 12:1-13.
doi: 10.2196/41197
2022
Magalhaes T, Morais CNL, Azevedo EAN, Jacques IJAA, Castanha PMS, Cordeiro MT, Braga C, Jaenisch T, Marques ETA, Foy BD. Two-year decay of Zika virus neutralizing antibodies in people living in an endemic region in Brazil. Am J Trop Med Hyg 2022; 107(1):186-189.
doi: 10.4269/ajtmh.21-1279
Cardoso CW, Souza MMS, Teles ACVS, Argibay HD, Reis OB, Pereira FM, Giovanetti M, Magalhaes T, Ribeiro GS. COVID-19 outbreaks among crew members in non-cruise vessels anchoring in Salvador, Brazil, 2021. Mem Inst Oswaldo Cruz 2022; 117:1-8.
2021
Gil L*, Magalhaes T*, Santos B, et al. Active Circulation of Madariaga Virus, a Member of the Eastern Equine Encephalitis Virus Complex, in Northeast Brazil. Pathogens 2021; 10. *Equal contribution
doi: 10.3390/pathogens10080983
Magalhaes T, Morais CNL, Jacques I, et al. Follow-Up Household Serosurvey in Northeast Brazil for Zika Virus: Sexual Contacts of Index Patients Have the Highest Risk for Seropositivity. J Infect Dis 2021; 223:673-85.
doi: 10.1093/infdis/jiaa563
Loeffler FF, Viana IFT, Fischer N, et al. Identification of a Zika NS2B epitope as a biomarker for severe clinical phenotypes. RSC Med Chem 2021; 12:1525-39.
doi: 10.1039/d1md00124h
Morales I, Rosenberger KD, Magalhaes T, et al. Diagnostic performance of anti-Zika virus IgM, IgAM and IgG ELISAs during co-circulation of Zika, dengue, and chikungunya viruses in Brazil and Venezuela. PLOS Negl Trop Dis 2021; 15:e0009336.
2020
Magalhaes T, Chalegre KDM, Braga C, Foy BD. The Endless Challenges of Arboviral Diseases in Brazil. Trop Med Infect Dis 2020; 5.
doi: 10.3390/tropicalmed5020075
Blitvich BJ, Magalhaes T, Laredo-Tiscareno SV, Foy BD. Sexual Transmission of Arboviruses: A Systematic Review. Viruses 2020; 12.
doi: 10.3390/v12090933
Armstrong PM, Ehrlich HY, Magalhaes T, et al. Successive blood meals enhance virus dissemination within mosquitoes and increase transmission potential. Nat Microbiol 2020; 5:239-47.
doi: 10.1038/s41564-019-0619-y
2019
Magalhaes T, Bergren NA, Bennett SL, et al. Induction of RNA interference to block Zika virus replication and transmission in the mosquito Aedes aegypti. Insect Biochem Mol Biol 2019; 111:103169.
doi: 10.1016/j.ibmb.2019.05.004
Foy BD, Alout H, Seaman JA, et al. Efficacy and risk of harms of repeat ivermectin mass drug administrations for control of malaria (RIMDAMAL): a cluster-randomised trial. Lancet 2019:10.
2018
Magalhaes T, Robison A, Young MC, et al. Sequential Infection of Aedes aegypti Mosquitoes with Chikungunya Virus and Zika Virus Enhances Early Zika Virus Transmission. Insects 2018; 9.
Magalhaes T, Foy BD, Marques ETA, Ebel GD, Weger-Lucarelli J. Mosquito-borne and sexual transmission of Zika virus: Recent developments and future directions. Virus Res 2018; 254:1-9.
2017
Magalhaes T, Braga C, Cordeiro MT, et al. Zika virus displacement by a chikungunya outbreak in Recife, Brazil. PLOS Negl Trop Dis 2017; 11:e0006055.
doi: 10.1371/journal.pntd.0006055
Faria NR, Quick J, Claro IM, et al. Establishment and cryptic transmission of Zika virus in Brazil and the Americas. Nature 2017; 546:406-10.
doi: 10.1038/nature22401
Chotiwan N, Brewster CD, Magalhaes T, et al. Rapid and specific detection of Asian- and African-lineage Zika viruses. Sci Transl Med 2017; 9.
doi: 10.1126/scitranslmed.aag0538
Bosch I, de Puig H, Hiley M, et al. Rapid antigen tests for dengue virus serotypes and Zika virus in patient serum. Sci Transl Med 2017; 9.
doi: 10.1126/scitranslmed.aan1589
Kassar TC, Magalhaes T, Junior SJ, et al. Construction and characterization of a recombinant yellow fever virus stably expressing Gaussia luciferase. An Acad Bras Cienc 2017; 89:2119-30.
doi: 10.1590/0001-3765201720160196
Freire M, Pol-Fachin L, Coelho DF, et al. Mapping Putative B-Cell Zika Virus NS1 Epitopes Provides Molecular Basis for Anti-NS1 Antibody Discrimination between Zika and Dengue Viruses. ACS Omega 2017; 2:3913-20.
doi: 10.1021/acsomega.7b00608