Katharine S. Walter

Katharine S. Walter, PhD

Languages spoken: Portuguese, French, English

Academic Information

Departments Adjunct - Human Genetics , Primary - Internal Medicine

Divisions: Epidemiology

Visit Katharine's group website here.

Research Statement

Pathogen evolution creates an extraordinary epidemiological record and staggering public health challenges. Our group develops and applies evolutionary approaches to answer open questions about pathogen transmission and epidemiological dynamics. We focus on tuberculosis and pathogens linked to the rapidly changing climate in the American West with a goal of directly informing public health in low-income settings

Education History

Undergraduate Harvard University
 BA
Graduate Training Université Paul Sabatier
 MSc
Graduate Training Yale School of Public Health
 MPhil
Graduate Training Yale School of Public Health
 PhD
Postdoctoral Fellowship Stanford University School of Medicine
 Postdoctoral Fellow

Selected Publications

Journal Article

  1. Adams B, Walter KS, Diuk-Wasser MA (2021). Host Specialisation, Immune Cross-Reaction and the Composition of Communities of Co-circulating Borrelia Strains. Bull Math Biol, 83(6), 66.
  2. Cords O, Martinez L, Warren JL, O'Marr JM, Walter KS, Cohen T, Zheng J, Ko AI, Croda J, Andrews JR (2021). Incidence and prevalence of tuberculosis in incarcerated populations: a systematic review and meta-analysis. Lancet Public Health, 6(5), e300-e308.
  3. Walter KS, Tatara MB, Esther da Silva K, Moreira FMF, Dos Santos PCP, de Melo Ferrari DD, Cunha EA, Andrews JR, Croda J (2021). Local and Travel-Associated Transmission of Tuberculosis at Central Western Border of Brazil, 2014-2017. Emerg Infect Dis, 27(3), 905-914.
  4. Walter KS, Colijn C, Cohen T, Mathema B, Liu Q, Bowers J, Engelthaler DM, Narechania A, Lemmer D, Croda J, Andrews JR (2020). Genomic variant-identification methods may alter Mycobacterium tuberculosis transmission inferences. Microb Genom, 6(8).
  5. Martinez L, Verma R, Croda J, Horsburgh CR Jr, Walter KS, Degner N, Middelkoop K, Koch A, Hermans S, Warner DF, Wood R, Cobelens F, Andrews JR (2019). Detection, survival and infectious potential of Mycobacterium tuberculosis in the environment: a review of the evidence and epidemiological implications. Eur Respir J, 53(6).
  6. Weiss BL, Maltz MA, Vigneron A, Wu Y, Walter KS, O'Neill MB, Wang J, Aksoy S (2019). Colonization of the tsetse fly midgut with commensal Kosakonia cowanii Zambiae inhibits trypanosome infection establishment. PLoS Pathog, 15(2), e1007470.
  7. Mabud TS, de Lourdes Delgado Alves M, Ko AI, Basu S, Walter KS, Cohen T, Mathema B, Colijn C, Lemos E, Croda J, Andrews JR (2019). Evaluating strategies for control of tuberculosis in prisons and prevention of spillover into communities: An observational and modeling study from Brazil. PLoS Med, 16(1), e1002737.
  8. Walter KS, Carpi G, Caccone A, Diuk-Wasser MA (2017). Genomic insights into the ancient spread of Lyme disease across North America. Nat Ecol Evol, 1(10), 1569-1576.
  9. Walter KS, Carpi G, Evans BR, Caccone A, Diuk-Wasser MA (2016). Vectors as Epidemiological Sentinels: Patterns of Within-Tick Borrelia burgdorferi Diversity. PLoS Pathog, 12(7), e1005759.
  10. Walter KS, Pepin KM, Webb CT, Gaff HD, Krause PJ, Pitzer VE, Diuk-Wasser MA (2016). Invasion of two tick-borne diseases across New England: harnessing human surveillance data to capture underlying ecological invasion processes. Proc Biol Sci, 283(1832).
  11. Carpi G, Walter KS, Mamoun CB, Krause PJ, Kitchen A, Lepore TJ, Dwivedi A, Cornillot E, Caccone A, Diuk-Wasser MA (2016). Babesia microti from humans and ticks hold a genomic signature of strong population structure in the United States. BMC Genomics, 17(1), 888.
  12. Carpi G, Walter KS, Bent SJ, Hoen AG, Diuk-Wasser M, Caccone A (2015). Whole genome capture of vector-borne pathogens from mixed DNA samples: a case study of Borrelia burgdorferi. BMC Genomics, 16, 434.
  13. Walter KS, Brown JE, Powell JR (2014). Microhabitat partitioning of Aedes simpsoni (Diptera: Culicidae). J Med Entomol, 51(3), 596-604.
  14. Alter G, Rihn S, Walter K, Nolting A, Martin M, Rosenberg ES, Miller JS, Carrington M, Altfeld M (2009). HLA class I subtype-dependent expansion of KIR3DS1+ and KIR3DL1+ NK cells during acute human immunodeficiency virus type 1 infection. J Virol, 83(13), 6798-805.
  15. Liu YE, Lemos EF, Gonçalves CCM, de Oliveira RD, Santos ADS, do Prado Morais AO, Croda MG, de Lourdes Delgado Alves M, Croda J, Walter KS, Andrews JR (2021). All-cause and cause-specific mortality during and following incarceration in Brazil: A retrospective cohort study. PLoS Med, 18(9), e1003789.
  16. O Marr JM, Gonçalves C, Arakaki-Sanchez D, Pelissari DM, Costa FD, Croda J, Walter KS, Andrews JR (2022). The effect of incarceration on TB treatment outcomes. Int J Tuberc Lung Dis, 26(3), 252-258.
  17. Verma R, Kim E, Degner N, Walter KS, Singh U, Andrews JR (2021). Variation in Severe Acute Respiratory Syndrome Coronavirus 2 Bioaerosol Production in Exhaled Breath. Open Forum Infect Dis, 9(1), ofab600.
  18. Verma R, Moreira FMF, do Prado Morais AO, Walter KS, Dos Santos PCP, Kim E, Soares TR, de Araujo RCP, da Silva BO, da Silva Santos A, Croda J, Andrews J (2022). Detection of M. tuberculosis in the environment as a tool for identifying high-risk locations for tuberculosis transmission. The Science of the total environment, 156970.
  19. Walter KS, Dos Santos PCP, Gonçalves TO, da Silva BO, da Silva Santos A, de Cássia Leite A, da Silva AM, Figueira Moreira FM, de Oliveira RD, Lemos EF, Cunha E, Liu YE, Ko AI, Colijn C, Cohen T, Mathema B, Croda J, Andrews J (2022). The role of prisons in disseminating tuberculosis in Brazil: A genomic epidemiology study. Lancet regional health. Americas, 9,
  20. Holubar M, Subramanian A, Purington N, Hedlin H, Bunning B, Walter KS, Bonilla H, Boumis A, Chen M, Clinton K, Dewhurst L, Epstein C, Jagannathan P, Kaszynski RH, Panu L, Parsonnet J, Ponder EL, Quintero O, Sefton E, Singh U, Soberanis L, Truong H, Andrews JR, Desai M, Khosla C, Maldonado (2022). Favipiravir for treatment of outpatients with asymptomatic or uncomplicated COVID-19: a double-blind randomized, placebo-controlled, phase 2 trial. Clinical infectious diseases,
  21. Sanabria GE, Sequera G, Aguirre S, Méndez J, Dos Santos PCP, Gustafson NW, Godoy M, Ortiz A, Cespedes C, Martínez G, García-Basteiro AL, Andrews JR, Croda J, Walter K (2023). Phylogeography and transmission of Mycobacterium tuberculosis spanning prisons and surrounding communities in Paraguay. Nature communications, 14(1), 303.
  22. Sobkowiak B, Cudahy P, Chitwood MH, Clark TG, Colijn C, Grandjean L, Walter KS, Crudu V, Cohen (2025). A new method for detecting mixed Mycobacterium tuberculosis infection and reconstructing constituent strains provides insights into transmission. Genome medicine, 17(1), 8.
  23. Nyathi S, Rezende IM, Walter KS, Thongsripong P, Mutuku F, Ndenga B, Mbakaya JO, Agola G, Vu DM, Bennett S, Mordecai EA, Andrews JR, LaBeaud A (2024). Geographic origin and evolution of dengue virus serotypes 1 and 3 circulating in Africa. Virus evolution, 11(1), veae116.
  24. Sequera G, Estigarribia-Sanabria G, Aguirre S, Piñanez C, Martinez L, Lopez-Olarte R, Andrews JR, Walter KS, Croda J, Garcia-Basteiro A (2024). Excess tuberculosis risk during and following incarceration in Paraguay: a retrospective cohort study. Lancet regional health. Americas, 31, 100668.
  25. Walter KS, Cohen T, Mathema B, Colijn C, Sobkowiak B, Comas I, Goig GA, Croda J, Andrews J (2025). Signatures of transmission in within-host Mycobacterium tuberculosis complex variation: a retrospective genomic epidemiology study. The Lancet. Microbe, 6(1), 100936.
  26. Nyathi S, Rezende IM, Walter KS, Thongsripong P, Mutuku F, Ndenga B, Mbakaya JO, Aswani P, Musunzaji PS, Chebii PK, Maina PW, Mutuku PS, Ng'ang'a CM, Malumbo SL, Jembe Z, Vu DM, Mordecai EA, Bennett S, Andrews JR, LaBeaud A (2024). Molecular epidemiology and evolutionary characteristics of dengue virus 2 in East Africa. Nature communications, 15(1), 7832.
  27. Medina A, Sussman J, Sosa N, Valdez M, Andrews JR, Croda J, Estigarribia Sanabria G, Sequera G, Aguirre S, Walter K (2024). The concentration of tuberculosis within Paraguay's incarcerated and Indigenous populations, 2018-2022.
  28. Walter KS, Cohen T, Mathema B, Colijn C, Sobkowiak B, Comas I, Goig GA, Croda J, Andrews J (2023). Signatures of transmission in within-host M. tuberculosis variation.
  29. Walter KS, Altamirano J, Huang C, Carrington YJ, Zhou F, Andrews JR, Maldonado (2023). Rapid emergence and transmission of virulence-associated mutations in the oral poliovirus vaccine following vaccination campaigns. NPJ vaccines, 8(1), 137.
  30. Fajer EB, Costa FD, Pelissari DM, Diaz Quijano FA, Coelho de Brito A, Cunha EAT, Croda J, Andrews JR, Walter K (2023). Use of rapid molecular TB diagnostics for incarcerated people in Brazil. The international journal of tuberculosis and lung disease, 27(5), 416-418.
  31. Walter KS, Altamirano J, Huang C, Carrington YJ, Zhou F, Andrews JR, Maldonado (2023). Rapid emergence and transmission of virulence-associated mutations in the oral poliovirus vaccine following vaccination campaigns.
  32. Walter KS, Kim E, Verma R, Altamirano J, Leary S, Carrington YJ, Jagannathan P, Singh U, Holubar M, Subramanian A, Khosla C, Maldonado Y, Andrews J (2023). Challenges in Harnessing Shared Within-Host Severe Acute Respiratory Syndrome Coronavirus 2 Variation for Transmission Inference. Open forum infectious diseases, 10(2), ofad001.

Review

  1. Walter KS, Martinez L, Arakaki-Sanchez D, Sequera VG, Estigarribia Sanabria G, Cohen T, Ko AI, García-Basteiro AL, Rueda ZV, López-Olarte RA, Espinal MA, Croda J, Andrews JR (2021). The escalating tuberculosis crisis in central and South American prisons. [Review]. Lancet, 397, (10284), 1591-1596.
  2. Metcalf CJE, Walter KS, Wesolowski A, Buckee CO, Shevliakova E, Tatem AJ, Boos WR, Weinberger DM, Pitzer VE (2017). Identifying climate drivers of infectious disease dynamics: recent advances and challenges ahead. [Review]. Proc Biol Sci, 284, (1860).

Editorial

  1. Sequera G, Aguirre S, Estigarribia G, Walter KS, Horna-Campos O, Liu YE, Andrews JR, Croda J, Garcia-Basteiro A (2024). Incarceration and TB: the epidemic beyond prison walls. BMJ global health, 9(2),

Abstract

  1. Altamirano J, Govindarajan P, Blomkalns AL, Learn S, Robinson I, Chun LX, Shaikh NJ, Robinso ML, De Araujo MB, Walter KS, Andrews JR, Hogan C, Pinksy BA, Madonado Y (2021). Natural History of Shedding and Household Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 Using Intensive High-Resolution Sampling [Abstract]. Open Forum Infectious Diseases, 8(Suppl 1), S302-S302.

Newspaper

  1. Walter K (2020). California’s inaction on COVID-19 amounts to a death sentence for prisoners.
  2. Walter K (2019). Ebola Outbreaks Are About Inequality.
  3. Walter K (2017). What We Get Wrong About Lyme Disease. 53.
  4. Walter K (2017). Central Park Mice Don’t Get Out Much. An interview with evolutionary biologist Jason Munshi-South. 51.
  5. Walter K (2017). How to Hear Like a Champion Birder. 50.
  6. Walter K (2017). How Aging Research Is Changing Our Lives: An interview with Eric Verdin, CEO of the Buck Institute for Research on Aging.
  7. Walter K (2016). Will Viruses Save Us From Superbugs?.
  8. Walter K (2016). Climate change is speeding up the spread of Lyme disease.
  9. Walter K (2022). Pandemic of the Oppressed.
  10. Walter K (2022). Let’s Build a City that Values Lives Over Handbags.