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Lagos RM, Sikorski MJ, Hormazábal JC, Fernandez A, Duarte S, Pasetti MF, Rasko DA, Higginson E, Nkeze J, Kasumba IN, Dougan G, Maes M, Lees A, Tennant SM, Levine MM. Detecting Residual Chronic Salmonella Typhi Carriers on the Road to Typhoid Elimination in Santiago, Chile, 2017-2019. J Infect Dis 2024; 230:e254-e267. [PMID: 38123455 PMCID: PMC11326835 DOI: 10.1093/infdis/jiad585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/12/2023] [Accepted: 12/17/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND In Santiago, Chile, where typhoid had been hyperendemic (1977-1991), we investigated whether residual chronic carriers could be detected among household contacts of non-travel-related typhoid cases occurring during 2017-2019. METHODS Culture-confirmed cases were classified as autochthonous (domestically acquired) versus travel/immigration related. Household contacts of cases had stool cultures and serum Vi antibody measurements to detect chronic Salmonella Typhi carriers. Whole genome sequences of acute cases and their epidemiologically linked chronic carrier isolates were compared. RESULTS Five of 16 autochthonous typhoid cases (31.3%) were linked to 4 chronic carriers in case households; 2 cases (onsets 23 months apart) were linked to the same carrier. Carriers were women aged 69-79 years with gallbladder dysfunction and Typhi fecal excretion; 3 had highly elevated serum anti-Vi titers. Genomic analyses revealed close identity (≤11 core genome single-nucleotide polymorphism [SNP] differences) between case and epidemiologically linked carrier isolates; all were genotypes prevalent in 1980s Santiago. A cluster of 4 additional autochthonous cases unlinked to a carrier was identified based on genomic identity (0-1 SNPs). Travel/immigration isolate genotypes were typical for the countries of travel/immigration. CONCLUSIONS Although autochthonous typhoid cases in Santiago are currently rare, 5 of 16 such cases (31.3%) were linked to elderly chronic carriers identified among household contacts of cases.
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Affiliation(s)
- Rosanna M Lagos
- Centro para Vacunas en Desarollo-Chile, Hospital de Niños Roberto del Río, Santiago, Chile
- Center for Vaccine Development and Global Health
| | - Michael J Sikorski
- Center for Vaccine Development and Global Health
- Institute for Genome Sciences, Center for Pathogen Research, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore
| | - Juan Carlos Hormazábal
- Sección Bacteriología, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile, Santiago
| | - Alda Fernandez
- Sección Bacteriología, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile, Santiago
| | - Sergio Duarte
- Sección Bacteriología, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile, Santiago
| | | | - David A Rasko
- Institute for Genome Sciences, Center for Pathogen Research, Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore
| | | | - Joseph Nkeze
- Center for Vaccine Development and Global Health
| | | | - Gordon Dougan
- Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, United Kingdom
| | - Mailis Maes
- Cambridge Institute for Therapeutic Immunology and Infectious Disease, University of Cambridge, United Kingdom
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Cid V, Vargas C, Delgado I, Apablaza M, Shiels MS, Hildesheim A, Koshiol J, Ferreccio C. Gallbladder cancer mortality in Chile: has the government program targeting young gallstone patients had an impact? Am J Epidemiol 2024; 193:1197-1202. [PMID: 38576158 DOI: 10.1093/aje/kwae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 02/22/2024] [Accepted: 03/28/2024] [Indexed: 04/06/2024] Open
Affiliation(s)
- Vicente Cid
- Rectory, Universidad de Santiago de Chile, Santiago 9170009, Chile
| | - Claudio Vargas
- Advanced Center for Chronic Diseases, Universidad de Chile and Pontificia Universidad Católica de Chile, Santiago 8330077, Chile
- Departamento de Matemáticas y Ciencias de la Computación, Facultad de Ciencias, Universidad de Santiago de Chile, Santiago 9170022, Chile
| | - Iris Delgado
- Center of Epidemiology and Public Health, Faculty of Medicine, Clínica Alemana Universidad del Desarrollo, Santiago 7610315, Chile
| | - Mauricio Apablaza
- School of Government, Universidad del Desarrollo, Santiago 7610315, Chile
| | - Meredith S Shiels
- Infections and Immunoepidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States
| | - Allan Hildesheim
- Infections and Immunoepidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States
| | - Jill Koshiol
- Infections and Immunoepidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD 20850, United States
| | - Catterina Ferreccio
- Advanced Center for Chronic Diseases, Universidad de Chile and Pontificia Universidad Católica de Chile, Santiago 8330077, Chile
- Department of Public Health, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330077, Chile
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LeBoa C, Shrestha S, Shakya J, Naga SR, Shrestha S, Shakya M, Yu AT, Shrestha R, Vaidya K, Katuwal N, Aiemjoy K, Bogoch II, Uzzell CB, Garrett DO, Luby SP, Andrews JR, Tamrakar D. Environmental sampling for typhoidal Salmonellas in household and surface waters in Nepal identifies potential transmission pathways. PLoS Negl Trop Dis 2023; 17:e0011341. [PMID: 37851667 PMCID: PMC10615262 DOI: 10.1371/journal.pntd.0011341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 10/30/2023] [Accepted: 09/06/2023] [Indexed: 10/20/2023] Open
Abstract
INTRODUCTION Salmonella Typhi and Salmonella Paratyphi, fecal-oral transmitted bacterium, have temporally and geographically heterogeneous pathways of transmission. Previous work in Kathmandu, Nepal implicated stone waterspouts as a dominant transmission pathway after 77% of samples tested positive for Salmonella Typhi and 70% for Salmonella Paratyphi. Due to a falling water table, these spouts no longer provide drinking water, but typhoid fever persists, and the question of the disease's dominant pathway of transmission remains unanswered. METHODS We used environmental surveillance to detect Salmonella Typhi and Salmonella Paratyphi A DNA from potential sources of transmission. We collected 370, 1L drinking water samples from a population-based random sample of households in the Kathmandu and Kavre Districts of Nepal between February and October 2019. Between November 2019 and July 2021, we collected 380, 50mL river water samples from 19 sentinel sites on a monthly interval along the rivers leading through the Kathmandu and Kavre Districts. We processed drinking water samples using a single qPCR and processed river water samples using differential centrifugation and qPCR at 0 and after 16 hours of liquid culture enrichment. A 3-cycle threshold (Ct) decrease of Salmonella Typhi or Salmonella Paratyphi, pre- and post-enrichment, was used as evidence of growth. We also performed structured observations of human-environment interactions to understand pathways of potential exposure. RESULTS Among 370 drinking water samples, Salmonella Typhi was detected in 7 samples (1.8%) and Salmonella Paratyphi A was detected in 4 (1.0%) samples. Among 380 river water samples, Salmonella Typhi was detected in 171 (45%) and Salmonella Paratyphi A was detected in 152 (42%) samples. Samples located upstream of the Kathmandu city center were positive for Salmonella Typhi 12% of the time while samples from locations in and downstream were positive 58% and 67% of the time respectively. Individuals were observed bathing, washing clothes, and washing vegetables in the rivers. IMPLICATIONS These results suggest that drinking water was not the dominant pathway of transmission of Salmonella Typhi and Salmonella Paratyphi A in the Kathmandu Valley in 2019. The high degree of river water contamination and its use for washing vegetables raises the possibility that river systems represent an important source of typhoid exposure in Kathmandu.
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Affiliation(s)
- Christopher LeBoa
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
- University of California Berkeley, Department of Environmental Health Sciences, Berkeley, California, United States of America
| | - Sneha Shrestha
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Jivan Shakya
- Institute for Research in Science and Technology, Lalitpur, Nepal
| | - Shiva Ram Naga
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Sony Shrestha
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Mudita Shakya
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Alexander T. Yu
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
| | - Rajeev Shrestha
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Krista Vaidya
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Nishan Katuwal
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
| | - Kristen Aiemjoy
- University of California Davis, Division of Public Health Sciences, California, United States of America
- Mahidol University Faculty of Tropical Medicine, Department of Microbiology and Immunology, Bangkok, Thailand
| | - Isaac I. Bogoch
- Toronto General Hospital, Division of Infectious Diseases, Toronto, Canada, and Department of Medicine, University of Toronto, Toronto Canada
| | - Christopher B. Uzzell
- Imperial College London, School of Public Health, Norfolk Place, London, United Kingdom
| | - Denise O. Garrett
- Sabin Vaccine Institute, Applied Epidemiology Section, Washington, DC, United States of America
| | - Stephen P. Luby
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
| | - Jason R. Andrews
- Stanford University, Division of Infectious Diseases and Geographic Medicine, Stanford, California, United States of America
| | - Dipesh Tamrakar
- Research and Development Division, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
- Center for Infectious Disease Research and Surveillance, Dhulikhel Hospital Kathmandu University Hospital, Kavre, Nepal
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Greear JA, Steele AD, Garrett DO. Achieving Impact: Charting the Course to Meet the Challenges Ahead at the 12th International Conference on Typhoid and Other Invasive Salmonelloses. Open Forum Infect Dis 2023; 10:S1-S5. [PMID: 37274525 PMCID: PMC10236503 DOI: 10.1093/ofid/ofad181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023] Open
Abstract
Typhoid fever and other invasive salmonelloses remain a major public health concern, primarily in low- and middle-income countries in Asia and Africa, where transmission occurs through contaminated food or water. However, recent developments in research, policy, and implementation offer newfound optimism for prevention and control. Now, more than ever, a coordinated and multisectoral global response is needed. To chart the course to meet the challenges ahead, the Coalition against Typhoid, housed at the Sabin Vaccine Institute, virtually organized the 12th International Conference on Typhoid and Other Invasive Salmonelloses from December 7 to 9, 2021. This commentary provides an overview of the conference's significant findings, highlighting barriers and opportunities for prevention and control. Topics covered include diagnostics advancements, improved data methodologies for a better understanding of the disease burden, the incorporation of environmental surveillance and genomics, the threat of drug resistance, and the use of typhoid conjugate vaccines alongside other integrated solutions.
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Affiliation(s)
- Jade A Greear
- Correspondence: Jade A. Greear, MA, Sabin Vaccine Institute, 2175 K Street NW, Suite 400, Washington, DC 20037 (); Denise O. Garrett, MD, Sabin Vaccine Institute, 2175 K Street NW, Suite 400, Washington, DC 20037 ()
| | - A Duncan Steele
- Enterics, Diagnostics, Genomics and Epidemiology, Global Health, Bill & Melinda Gates Foundation, Seattle, Washington, USA
| | - Denise O Garrett
- Correspondence: Jade A. Greear, MA, Sabin Vaccine Institute, 2175 K Street NW, Suite 400, Washington, DC 20037 (); Denise O. Garrett, MD, Sabin Vaccine Institute, 2175 K Street NW, Suite 400, Washington, DC 20037 ()
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Vanderslott S, Kumar S, Adu-Sarkodie Y, Qadri F, Zellweger RM. Typhoid Control in an Era of Antimicrobial Resistance: Challenges and Opportunities. Open Forum Infect Dis 2023; 10:S47-S52. [PMID: 37274528 PMCID: PMC10236512 DOI: 10.1093/ofid/ofad135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023] Open
Abstract
Historically, typhoid control has been achieved with water and sanitation interventions. Today, in an era of rising antimicrobial resistance (AMR), two World Health Organization-prequalified vaccines are available to accelerate control in the shorter term. Meanwhile, water and sanitation interventions could be implemented in the longer term to sustainably prevent typhoid in low- and middle-income countries. This article first approaches typhoid control from a historical perspective, subsequently presents how vaccination could complement water and sanitation activities, and finally discusses the challenges and opportunities for impactful control of typhoid infection. It also addresses data blind spots and knowledge gaps to focus on for typhoid control and to ultimately progress towards elimination. This article presents a synthesis of discussions held in December 2021 during a roundtable session at the "12th International Conference on Typhoid and Other Invasive Salmonelloses".
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Affiliation(s)
- Samantha Vanderslott
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom and NIHR Oxford Biomedical Research Centre, Oxford, Oxfordshire, United Kingdom
| | - Supriya Kumar
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington, USA
| | - Yaw Adu-Sarkodie
- Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Raphaël M Zellweger
- Correspondence: Raphaël M. Zellweger, MSc, PhD, Epidemiology , Public Health & Impact, International Vaccine Institute, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea. ()
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Maes M, Sikorski MJ, Carey ME, Higginson EE, Dyson ZA, Fernandez A, Araya P, Tennant SM, Baker S, Lagos R, Hormazábal JC, Levine MM, Dougan G. Whole genome sequence analysis of Salmonella Typhi provides evidence of phylogenetic linkage between cases of typhoid fever in Santiago, Chile in the 1980s and 2010-2016. PLoS Negl Trop Dis 2022; 16:e0010178. [PMID: 35767580 PMCID: PMC9275700 DOI: 10.1371/journal.pntd.0010178] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/12/2022] [Accepted: 06/08/2022] [Indexed: 11/25/2022] Open
Abstract
Typhoid fever epidemiology was investigated rigorously in Santiago, Chile during the 1980s, when Salmonella enterica serovar Typhi (S. Typhi) caused seasonal, hyperendemic disease. Targeted interventions reduced the annual typhoid incidence rates from 128–220 cases/105 population occurring between 1977–1984 to <8 cases/105 from 1992 onwards. As such, Santiago represents a contemporary example of the epidemiologic transition of an industrialized city from amplified hyperendemic typhoid fever to a period when typhoid is no longer endemic. We used whole genome sequencing (WGS) and phylogenetic analysis to compare the genotypes of S. Typhi cultured from acute cases of typhoid fever occurring in Santiago during the hyperendemic period of the 1980s (n = 74) versus the nonendemic 2010s (n = 80) when typhoid fever was rare. The genotype distribution between “historical” (1980s) isolates and “modern” (2011–2016) isolates was similar, with genotypes 3.5 and 2 comprising the majority of isolations, and 73/80 (91.3%) of modern isolates matching a genotype detected in the 1980s. Additionally, phylogenomically ‘ancient’ genotypes 1.1 and 1.2.1, uncommon in the global collections, were also detected in both eras, with a notable rise amongst the modern isolates. Thus, genotypes of S. Typhi causing acute illness in the modern nonendemic era match the genotypes circulating during the hyperendemic 1980s. The persistence of historical genotypes may be explained by chronic typhoid carriers originally infected during or before the 1980s. Studies of Salmonella Typhi (the cause of typhoid fever) rarely include isolates collected both before and after the interruption of hyperendemic transmission because this typically occurred decades before modern bacteria preservation methods. After substantial reduction in disease, it was assumed that sporadic cases and infrequent outbreaks were due to either chronic biliary carriers or importations, but this was difficult to characterize with low resolution bacterial typing methods. In Santiago, Chile, typhoid fever persisted at hyperendemic levels through the 1980s until organized control efforts in the 1980s and changes to wastewater policy in 1991 caused annual typhoid incidence to plummet. In this study, we used whole genome sequencing (WGS) to investigate whether recent sporadic cases occurring in Santiago in the 2010s were genomically similar to S. Typhi circulating in the 1980s, or dissimilar, possibly representing importations of S. Typhi from outside of Chile. We found concordance amongst S. Typhi genotypes between the 1980s and 2010s, and differences from genotypes circulating in Southeast Asia and Africa where typhoid remains hyperendemic. Our findings suggest that a proportion of modern, rare typhoid cases in Santiago are autochthonous, and that chronic carriers or another unknown reservoir likely contribute. Broadly, our findings corroborate the epidemiologic importance of long-term reservoirs of typhoid fever decades after typhoid elimination.
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Affiliation(s)
- Mailis Maes
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
| | - Michael J. Sikorski
- Center for Vaccine Development and Global Health (CVD), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Megan E. Carey
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Ellen E. Higginson
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Zoe A. Dyson
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Department of Infectious Diseases, Monash University, Melbourne, Australia
- London School of Hygiene & Tropical Medicine, London, United Kingdom
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Alda Fernandez
- Bacteriologia, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile (ISP), Santiago, Chile
| | - Pamela Araya
- Bacteriologia, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile (ISP), Santiago, Chile
| | - Sharon M. Tennant
- Center for Vaccine Development and Global Health (CVD), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Rosanna Lagos
- Centro para Vacunas en Desarollo-Chile (CVD-Chile), Hospital de Niños Roberto del Rio, Santiago, Chile
| | - Juan Carlos Hormazábal
- Bacteriologia, Subdepartamento de Enfermedades Infecciosas, Departamento de Laboratorio Biomédico, Instituto de Salud Pública de Chile (ISP), Santiago, Chile
| | - Myron M. Levine
- Center for Vaccine Development and Global Health (CVD), University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Gordon Dougan
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
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Guevara PD, Maes M, Thanh DP, Duarte C, Rodriguez EC, Montaño LA, Dan THN, Nguyen TNT, Carey ME, Campos J, Chinen I, Perez E, Baker S. A genomic snapshot of Salmonella enterica serovar Typhi in Colombia. PLoS Negl Trop Dis 2021; 15:e0009755. [PMID: 34529660 PMCID: PMC8478212 DOI: 10.1371/journal.pntd.0009755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 09/28/2021] [Accepted: 08/24/2021] [Indexed: 11/23/2022] Open
Abstract
Little is known about the genetic diversity of Salmonella enterica serovar Typhi (S. Typhi) circulating in Latin America. It has been observed that typhoid fever is still endemic in this part of the world; however, a lack of standardized blood culture surveillance across Latin American makes estimating the true disease burden problematic. The Colombian National Health Service established a surveillance system for tracking bacterial pathogens, including S. Typhi, in 2006. Here, we characterized 77 representative Colombian S. Typhi isolates collected between 1997 and 2018 using pulse field gel electrophoresis (PFGE; the accepted genotyping method in Latin America) and whole genome sequencing (WGS). We found that the main S. Typhi clades circulating in Colombia were clades 2.5 and 3.5. Notably, the sequenced S. Typhi isolates from Colombia were closely related in a global phylogeny. Consequently, these data suggest that these are endemic clades circulating in Colombia. We found that AMR in S. Typhi in Colombia was uncommon, with a small subset of organisms exhibiting mutations associated with reduced susceptibility to fluoroquinolones. This is the first time that S. Typhi isolated from Colombia have been characterized by WGS, and after comparing these data with those generated using PFGE, we conclude that PFGE is unsuitable for tracking S. Typhi clones and mapping transmission. The genetic diversity of pathogens such as S. Typhi is limited in Latin America and should be targeted for future surveillance studies incorporating WGS.
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Affiliation(s)
| | - Mailis Maes
- University of Cambridge School of Clinical Medicine Department of Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Level 5 Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Carolina Duarte
- Grupo de Microbiología, Instituto Nacional de Salud, Bogotá, Colombia
| | | | | | - Thanh Ho Ngoc Dan
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - To Nguyen Thi Nguyen
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Megan E. Carey
- University of Cambridge School of Clinical Medicine Department of Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Level 5 Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - Josefina Campos
- Red Pulsenet Latinoamérica y el Caribe, INEI-ANLIS “Dr Carlos Malbran, Buenos Aires, Argentina
| | - Isabel Chinen
- Red Pulsenet Latinoamérica y el Caribe, INEI-ANLIS “Dr Carlos Malbran, Buenos Aires, Argentina
| | - Enrique Perez
- Health Emergencies Department, Pan American Health Organization/World Health Organization, PAHO/WHO, Washington DC, United States of America
| | - Stephen Baker
- University of Cambridge School of Clinical Medicine Department of Medicine, Cambridge Biomedical Campus, Cambridge, United Kingdom
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Level 5 Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
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Maes M, Dyson ZA, Higginson EE, Fernandez A, Araya P, Tennant SM, Baker S, Lagos R, Levine MM, Hormazabal JC, Dougan G. Multiple Introductions of Salmonella enterica Serovar Typhi H58 with Reduced Fluoroquinolone Susceptibility into Chile. Emerg Infect Dis 2020; 26:2736-2740. [PMID: 33079054 PMCID: PMC7588544 DOI: 10.3201/eid2611.201676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Salmonella enterica serovar Typhi H58, an antimicrobial-resistant lineage, is globally disseminated but has not been reported in Latin America. Genomic analysis revealed 3 independent introductions of Salmonella Typhi H58 with reduced fluoroquinolone susceptibility into Chile. Our findings highlight the utility of enhanced genomic surveillance for typhoid fever in this region.
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Reviving the "Moore Swab": a Classic Environmental Surveillance Tool Involving Filtration of Flowing Surface Water and Sewage Water To Recover Typhoidal Salmonella Bacteria. Appl Environ Microbiol 2020; 86:AEM.00060-20. [PMID: 32332133 PMCID: PMC7301852 DOI: 10.1128/aem.00060-20] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The “Moore swab” is a classic environmental surveillance tool whereby a gauze pad tied with string is suspended in flowing water or wastewater contaminated with human feces and harboring enteric pathogens that pose a human health threat. In contrast to single volume “grab” samples, Moore swabs act as continuous filters to “trap” microorganisms, which are subsequently isolated and confirmed using appropriate laboratory methods. Continuous filtration is valuable for the isolation of transiently present pathogens such as human-restricted Salmonella enterica serovars Typhi and Paratyphi A and B. The “Moore swab” is a classic environmental surveillance tool whereby a gauze pad tied with string is suspended in flowing water or wastewater contaminated with human feces and harboring enteric pathogens that pose a human health threat. In contrast to single volume “grab” samples, Moore swabs act as continuous filters to “trap” microorganisms, which are subsequently isolated and confirmed using appropriate laboratory methods. Continuous filtration is valuable for the isolation of transiently present pathogens such as human-restricted Salmonella enterica serovars Typhi and Paratyphi A and B. The technique was first proposed (1948) to trace Salmonella Paratyphi B systematically through sewers to pinpoint the residence of a chronic carrier responsible for sporadic outbreaks of paratyphoid fever. From 1948 to 1986, Moore swabs proved instrumental to identify long-term human reservoirs (chronic carriers) and long-cycle environmental transmission pathways of S. Typhi and Paratyphi, for example, to decipher endemic transmission in Santiago, Chile, during the 1980s. Despite limitations such as intermittent shedding of typhoidal Salmonella by humans and the effects of dilution, S. Typhi and S. Paratyphi have been recovered from sewers, surface waters, irrigation canals, storm drains, flush toilets, and septic tanks by using Moore swabs. Driven by the emergence of multiple antibiotic-resistant S. Typhi and S. Paratyphi A strains that limit treatment options, several countries are embarking on accelerated typhoid control programs using vaccines and environmental interventions. Moore swabs, which are regaining appreciation as important components of the public health/environmental microbiology toolbox, can enhance environmental surveillance for typhoidal Salmonella, thereby contributing to the control of typhoid fever.
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Abstract
We combine methodology from history and genetics to reconstruct the biosocial history of antimicrobial resistance (AMR) in the bacterium Salmonella enterica serovar Typhi (S. Typhi). We show how evolutionary divergence in S. Typhi was driven by rising global antibiotic use and by the neglect of typhoid outside of high-income countries. Although high-income countries pioneered 1960s precautionary antibiotic regulations to prevent selection for multidrug resistance, new antibiotic classes, typhoid's cultural status as a supposedly ancient disease of "undeveloped" countries, limited international funding, and narrow biosecurity agendas helped fragment effective global collective action for typhoid control. Antibiotic-intensive compensation for weak water and healthcare systems subsequently fueled AMR selection in low- and middle-income countries but often remained invisible due to lacking surveillance capabilities. The recent rise of extensively drug-resistant typhoid bears the biosocial footprint of more than half a century of antibiotic-intensive international neglect.
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Affiliation(s)
- Claas Kirchhelle
- Wellcome Unit for the History of Medicine/Oxford Martin School, University of Oxford, Addenbrooke’s Hospital, United Kingdom
| | - Zoe Anne Dyson
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, United Kingdom
| | - Gordon Dougan
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, United Kingdom
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Typhoid fever in Santiago, Chile: Insights from a mathematical model utilizing venerable archived data from a successful disease control program. PLoS Negl Trop Dis 2018; 12:e0006759. [PMID: 30188904 PMCID: PMC6143279 DOI: 10.1371/journal.pntd.0006759] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 09/18/2018] [Accepted: 08/16/2018] [Indexed: 12/04/2022] Open
Abstract
Typhoid fever is endemic in many developing countries. In the early 20th century, newly industrializing countries including the United States successfully controlled typhoid as water treatment (chlorination/sand filtration) and improved sanitation became widespread. Enigmatically, typhoid remained endemic through the 1980s in Santiago, Chile, despite potable municipal water and widespread household sanitation. Data were collected across multiple stages of endemicity and control in Santiago, offering a unique resource for gaining insight into drivers of transmission in modern settings. We developed an individual-based mathematical model of typhoid transmission, with model components including distinctions between long-cycle and short-cycle transmission routes. Data used to fit the model included the prevalence of chronic carriers, seasonality, longitudinal incidence, and age-specific distributions of typhoid infection and disease. Our model captured the dynamics seen in Santiago across endemicity, vaccination, and environmental control. Both vaccination and diminished exposure to seasonal amplified long-cycle transmission contributed to the observed declines in typhoid incidence, with the vaccine estimated to elicit herd effects. Vaccines are important tools for controlling endemic typhoid, with even limited coverage eliciting herd effects in this setting. Removing the vehicles responsible for amplified long-cycle transmission and assessing the role of chronic carriers in endemic settings are additional key elements in designing programs to achieve accelerated control of endemic typhoid. Typhoid fever was successfully controlled in Santiago, Chile, after a series of interventions including vaccination with a live oral vaccine (Ty21a), and an environmental sanitation improvement, when a ban was put on the irrigation of salad vegetable crops with untreated sewage. Data collected during this period inform seasonality, age distribution and longitudinal trends of disease. We developed an individual-based, mathematical model to both simulate the dynamics of typhoid seen in Santiago, as well as to investigate relative impacts of the vaccine and sanitation interventions. We found that herd immunity resulted from field trials of the Ty21a vaccine and that chronic carriers were a likely driver of sustained transmission at low incidence levels. Modeling typhoid fever in areas that have demonstrated successful control provides insight for control strategies in modern settings.
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Barac R, Als D, Radhakrishnan A, Gaffey MF, Bhutta ZA, Barwick M. Implementation of Interventions for the Control of Typhoid Fever in Low- and Middle-Income Countries. Am J Trop Med Hyg 2018; 99:79-88. [PMID: 30047365 PMCID: PMC6128369 DOI: 10.4269/ajtmh.18-0110] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/05/2018] [Indexed: 01/12/2023] Open
Abstract
Past research has focused on typhoid fever surveillance with little attention to implementation methods or effectiveness of control interventions. This study purposefully sampled key informants working in public health in Chile, India, Pakistan, Bangladesh, Thailand, Vietnam, South Africa, and Nigeria to 1) scope typhoid-relevant interventions implemented between 1990 and 2015 and 2) explore contextual factors perceived to be associated with their implementation, based on the Consolidated Framework for Implementation Research (CFIR). We used a mixed methods design and collected quantitative data (CFIR questionnaire) and qualitative data (interviews with 34 public health experts). Interview data were analyzed using a deductive qualitative content analysis and summary descriptive statistics are provided for the CFIR data. Despite relatively few typhoid-specific interventions reportedly implemented in these countries, interventions for diarrheal disease control and regulations for food safety and food handlers were common. Most countries implemented agricultural and sewage treatment practices, yet few addressed the control of antibiotic medication. Several contextual factors were perceived to have influenced the implementation of typhoid interventions, either as enablers (e.g., economic development) or barriers (e.g., limited resources and habitual behaviors). Consolidated Framework for Implementation Research factors rated as important in the implementation of typhoid interventions were remarkably consistent across countries. The findings provide a snapshot of typhoid-relevant interventions implemented over 25 years and highlight factors associated with implementation success from the perspective of a sample of key informants. These findings can inform systematic investigations of the implementation of typhoid control interventions and contribute to a better understanding of the direct effects of implementation efforts.
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Affiliation(s)
- Raluca Barac
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Daina Als
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | | | - Michelle F. Gaffey
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | - Zulfiqar A. Bhutta
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
- Center of Excellence in Women and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Melanie Barwick
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Research Institute, The Hospital for Sick Children, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
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Bhutta ZA, Gaffey MF, Crump JA, Steele D, Breiman RF, Mintz ED, Black RE, Luby SP, Levine MM. Typhoid Fever: Way Forward. Am J Trop Med Hyg 2018; 99:89-96. [PMID: 30047361 PMCID: PMC6128357 DOI: 10.4269/ajtmh.18-0111] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The Tackling Typhoid supplement shows that typhoid fever continues to be a problem globally despite socioeconomic gains in certain settings. Morbidity remains high in many endemic countries, notably in sub-Saharan Africa and South Asia. In addition, antimicrobial resistance is a growing issue that poses a challenge for clinical management. The findings from this supplement revealed that outside of high-income countries, there were few reliable population-based estimates of typhoid and paratyphoid fever derived from surveillance systems. This indicates the need for monitoring systems that can also characterize the effectiveness of interventions, particularly in low- and middle-income settings. The country case studies indicated that gains in economic conditions, education, and environmental health may be associated with reductions in typhoid fever burden. Over the study period, the effect is mainly notable in countries with higher baseline levels of economic development, female literacy, and investments in public sanitation. High burden countries must continue to invest in strategies at the local level to address environmental factors such as access to safe drinking water and improved public sanitation that are known to interrupt transmission or diminish the risk of acquiring typhoid. Developing more effective vaccines and incorporating appropriate immunization strategies that target populations with the greatest risk could potentially alleviate disease burden.
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Affiliation(s)
- Zulfiqar A Bhutta
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada.,Dalla Lana School of Public Health, University of Toronto, Toronto, Canada.,Center of Excellence in Women and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Michelle F Gaffey
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Duncan Steele
- Enteric and Diarrheal Diseases, Bill & Melinda Gates Foundation, Seattle, Washington
| | - Robert F Breiman
- Emory Global Health Institute, Emory University, Atlanta, Georgia
| | - Eric D Mintz
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Robert E Black
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Stephen P Luby
- Centre for Innovation in Global Health, Woods Institute for the Environment, Stanford University, Stanford, California
| | - Myron M Levine
- Global Health, Vaccinology and Infectious Diseases, University of Maryland School of Medicine, Baltimore, Maryland
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