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Vazquez-Prokopec GM, Morrison AC, Paz-Soldan V, Stoddard ST, Koval W, Waller LA, Alex Perkins T, Lloyd AL, Astete H, Elder J, Scott TW, Kitron U. Inapparent infections shape the transmission heterogeneity of dengue. PNAS NEXUS 2023; 2:pgad024. [PMID: 36909820 PMCID: PMC10003742 DOI: 10.1093/pnasnexus/pgad024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 01/08/2023] [Accepted: 01/17/2023] [Indexed: 02/02/2023]
Abstract
Transmission heterogeneity, whereby a disproportionate fraction of pathogen transmission events result from a small number of individuals or geographic locations, is an inherent property of many, if not most, infectious disease systems. For vector-borne diseases, transmission heterogeneity is inferred from the distribution of the number of vectors per host, which could lead to significant bias in situations where vector abundance and transmission risk at the household do not correlate, as is the case with dengue virus (DENV). We used data from a contact tracing study to quantify the distribution of DENV acute infections within human activity spaces (AS), the collection of residential locations an individual routinely visits, and quantified measures of virus transmission heterogeneity from two consecutive dengue outbreaks (DENV-4 and DENV-2) that occurred in the city of Iquitos, Peru. Negative-binomial distributions and Pareto fractions showed evidence of strong overdispersion in the number of DENV infections by AS and identified super-spreading units (SSUs): i.e. AS where most infections occurred. Approximately 8% of AS were identified as SSUs, contributing to more than 50% of DENV infections. SSU occurrence was associated more with DENV-2 infection than with DENV-4, a predominance of inapparent infections (74% of all infections), households with high Aedes aegypti mosquito abundance, and high host susceptibility to the circulating DENV serotype. Marked heterogeneity in dengue case distribution, and the role of inapparent infections in defining it, highlight major challenges faced by reactive interventions if those transmission units contributing the most to transmission are not identified, prioritized, and effectively treated.
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Affiliation(s)
| | - Amy C Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Valerie Paz-Soldan
- Department of Global Community Health and Behavioral Sciences, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA 70112, USA
| | - Steven T Stoddard
- Division of Health Promotion & Behavioral Sciences, School of Public Health, San Diego State University, San Diego, CA 92182, USA
| | - William Koval
- Department of Biology, University of Chicago, Chicago, IL 60637, USA
| | - Lance A Waller
- Department of Biostatistics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - T Alex Perkins
- Department of Biology, University of Notre Dame, South Bend, IN 46556, USA
| | - Alun L Lloyd
- Biomathematics Graduate Program and Department of Mathematics, North Carolina State University, Raleigh, NC 27607, USA
| | - Helvio Astete
- Virology Department, Naval Medical Research Unit-6, Iquitos 16003, Peru
| | - John Elder
- Division of Health Promotion & Behavioral Sciences, School of Public Health, San Diego State University, San Diego, CA 92182, USA
| | - Thomas W Scott
- Department of Entomology and Nematology, University of California, Davis, CA 95616, USA
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, GA 30322, USA
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Morrison AC, Paz-Soldan VA, Vazquez-Prokopec GM, Lambrechts L, Elson WH, Barrera P, Astete H, Briesemeister V, Leguia M, Jenkins SA, Long KC, Kawiecki AB, Reiner RC, Perkins TA, Lloyd AL, Waller LA, Hontz RD, Stoddard ST, Barker CM, Kitron U, Elder JP, Rothman AL, Scott TW. Quantifying heterogeneities in arbovirus transmission: Description of the rationale and methodology for a prospective longitudinal study of dengue and Zika virus transmission in Iquitos, Peru (2014-2019). PLoS One 2023; 18:e0273798. [PMID: 36730229 PMCID: PMC9894416 DOI: 10.1371/journal.pone.0273798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/15/2022] [Indexed: 02/03/2023] Open
Abstract
Current knowledge of dengue virus (DENV) transmission provides only a partial understanding of a complex and dynamic system yielding a public health track record that has more failures than successes. An important part of the problem is that the foundation for contemporary interventions includes a series of longstanding, but untested, assumptions based on a relatively small portion of the human population; i.e., people who are convenient to study because they manifest clinically apparent disease. Approaching dengue from the perspective of people with overt illness has produced an extensive body of useful literature. It has not, however, fully embraced heterogeneities in virus transmission dynamics that are increasingly recognized as key information still missing in the struggle to control the most important insect-transmitted viral infection of humans. Only in the last 20 years have there been significant efforts to carry out comprehensive longitudinal dengue studies. This manuscript provides the rationale and comprehensive, integrated description of the methodology for a five-year longitudinal cohort study based in the tropical city of Iquitos, in the heart of the Peruvian Amazon. Primary data collection for this study was completed in 2019. Although some manuscripts have been published to date, our principal objective here is to support subsequent publications by describing in detail the structure, methodology, and significance of a specific research program. Our project was designed to study people across the entire continuum of disease, with the ultimate goal of quantifying heterogeneities in human variables that affect DENV transmission dynamics and prevention. Because our study design is applicable to other Aedes transmitted viruses, we used it to gain insights into Zika virus (ZIKV) transmission when during the project period ZIKV was introduced and circulated in Iquitos. Our prospective contact cluster investigation design was initiated by detecttion of a person with a symptomatic DENV infection and then followed that person's immediate contacts. This allowed us to monitor individuals at high risk of DENV infection, including people with clinically inapparent and mild infections that are otherwise difficult to detect. We aimed to fill knowledge gaps by defining the contribution to DENV transmission dynamics of (1) the understudied majority of DENV-infected people with inapparent and mild infections and (2) epidemiological, entomological, and socio-behavioral sources of heterogeneity. By accounting for factors underlying variation in each person's contribution to transmission we sought to better determine the type and extent of effort needed to better prevent virus transmission and disease.
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Affiliation(s)
- Amy C. Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
- * E-mail: ,
| | - Valerie A. Paz-Soldan
- Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, Lousiana, United States of America
| | | | - Louis Lambrechts
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, Paris, France
| | - William H. Elson
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Patricia Barrera
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
- Genomics Laboratory, Pontificia Universidad Católica del Peru, Lima, Peru
| | - Helvio Astete
- Virology and Emerging Infections Department, United States Naval Medical Research Unit No. 6, Lima, Peru
- Department of Entomology, United States Naval Medical Research Unit No. 6, Lima, Peru
| | - Veronica Briesemeister
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Mariana Leguia
- Genomics Laboratory, Pontificia Universidad Católica del Peru, Lima, Peru
| | - Sarah A. Jenkins
- Virology and Emerging Infections Department, United States Naval Medical Research Unit No. 6, Lima, Peru
| | - Kanya C. Long
- Department of Family Medicine and Public Health, University of California San Diego School of Medicine, La Jolla, California, United States of America
| | - Anna B. Kawiecki
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Robert C. Reiner
- University of Washington, Seattle, Washington, United States of America
| | - T. Alex Perkins
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Alun L. Lloyd
- Biomathematics Graduate Program and Department of Mathematics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Lance A. Waller
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - Robert D. Hontz
- Virology and Emerging Infections Department, United States Naval Medical Research Unit No. 6, Lima, Peru
| | - Steven T. Stoddard
- School of Public Health, San Diego State University, San Diego, California, United States of America
| | - Christopher M. Barker
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, California, United States of America
| | - Uriel Kitron
- Institut Pasteur, Université Paris Cité, CNRS UMR2000, Insect-Virus Interactions Unit, Paris, France
| | - John P. Elder
- School of Public Health, San Diego State University, San Diego, California, United States of America
| | - Alan L. Rothman
- Institute for Immunology and Informatics and Department of Cell and Molecular Biology, University of Rhode Island, Providence, Rhode Island, United States of America
| | - Thomas W. Scott
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
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Watts DM, Russell KL, Wooster MT, Sharp TW, Morrison AC, Kochel TJ, Bautista CT, Block K, Guevara C, Aguilar P, Palermo PM, Calampa C, Porter KR, Hayes CG, Weaver SC, de Rosa AT, Vinetz JM, Shope RE, Gotuzzo E, Guzman H, Tesh RB. Etiologies of Acute Undifferentiated Febrile Illnesses in and near Iquitos from 1993 to 1999 in the Amazon River Basin of Peru. Am J Trop Med Hyg 2022; 107:1114-1128. [PMID: 36162442 PMCID: PMC9709010 DOI: 10.4269/ajtmh.22-0259] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/10/2022] [Indexed: 11/07/2022] Open
Abstract
The objective of this study was to determine the etiology of febrile illnesses among patients from October 1, 1993 through September 30, 1999, in the urban community of Iquitos in the Amazon River Basin of Peru. Epidemiological and clinical data as well as blood samples were obtained from consenting patients at hospitals, health clinics and private residences. Samples were tested for arboviruses in cell cultures and for IgM and IgG antibodies by ELISA. Blood smears were examined for malaria, and sera were tested for antibodies to Leptospira spp. by ELISA and microscopic agglutination. Among 6,607 febrile patients studied, dengue viruses caused 14.6% of the cases, and Venezuelan equine encephalitis virus caused 2.5%, Oropouche virus 1.0%, Mayaro virus 0.4%, and other arboviruses caused 0.2% of the cases. Also, 22.9% of 4,844 patients tested were positive for malaria, and of 400 samples tested, 9% had evidence of acute leptospirosis. Although the study was not designed to assess the importance of these pathogens as a cause of human morbidity in the total population, these results indicate that arboviruses, leptospirosis, and malaria were the cause of approximately 50% of the febrile cases. Although the arboviruses that were diagnosed can produce asymptomatic infections, our findings increased the overall understanding of the relative health burden of these infections, as well as baseline knowledge needed for designing and implementing further studies to better assess the health impact and threat of these pathogens in the Amazon Basin of Peru.
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Affiliation(s)
- Douglas M. Watts
- U.S. Naval Medical Research Unit No. 6, Lima, Peru;,Address correspondence to Douglas M. Watts, Department of Biological Sciences, University of Texas at El Paso, 500 W. University Ave., El Paso, TX 79968. E-mail:
| | | | | | | | - Amy C. Morrison
- University of California, Davis School of Veterinary Medicine Department of Pathology, Microbiology, and Immunology, Davis, California
| | | | | | - Karla Block
- U.S. Naval Medical Research Unit No. 6, Lima, Peru
| | | | - Patricia Aguilar
- World Reference Center for Emerging Viruses and Arboviruses University of Texas Medical Branch, Galveston, Texas
| | | | - Carlos Calampa
- Peruvian Ministry of Health, Loreto Health Subregion, Iquitos, Peru
| | | | | | - Scott C. Weaver
- World Reference Center for Emerging Viruses and Arboviruses University of Texas Medical Branch, Galveston, Texas
| | - Amelia Travassos de Rosa
- World Reference Center for Emerging Viruses and Arboviruses University of Texas Medical Branch, Galveston, Texas
| | - Joseph M. Vinetz
- World Reference Center for Emerging Viruses and Arboviruses University of Texas Medical Branch, Galveston, Texas
| | - Robert E. Shope
- World Reference Center for Emerging Viruses and Arboviruses University of Texas Medical Branch, Galveston, Texas
| | - Eduardo Gotuzzo
- Department of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Hilda Guzman
- World Reference Center for Emerging Viruses and Arboviruses University of Texas Medical Branch, Galveston, Texas
| | - Robert B. Tesh
- World Reference Center for Emerging Viruses and Arboviruses University of Texas Medical Branch, Galveston, Texas
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Lefebvre B, Karki R, Misslin R, Nakhapakorn K, Daudé E, Paul RE. Importance of Public Transport Networks for Reconciling the Spatial Distribution of Dengue and the Association of Socio-Economic Factors with Dengue Risk in Bangkok, Thailand. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:10123. [PMID: 36011755 PMCID: PMC9408777 DOI: 10.3390/ijerph191610123] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/07/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Dengue is the most widespread mosquito-borne viral disease of man and spreading at an alarming rate. Socio-economic inequality has long been thought to contribute to providing an environment for viral propagation. However, identifying socio-economic (SE) risk factors is confounded by intra-urban daily human mobility, with virus being ferried across cities. This study aimed to identify SE variables associated with dengue at a subdistrict level in Bangkok, analyse how they explain observed dengue hotspots and assess the impact of mobility networks on such associations. Using meteorological, dengue case, national statistics, and transport databases from the Bangkok authorities, we applied statistical association and spatial analyses to identify SE variables associated with dengue and spatial hotspots and the extent to which incorporating transport data impacts the observed associations. We identified three SE risk factors at the subdistrict level: lack of education, % of houses being cement/brick, and number of houses as being associated with increased risk of dengue. Spatial hotspots of dengue were found to occur consistently in the centre of the city, but which did not entirely have the socio-economic risk factor characteristics. Incorporation of the intra-urban transport network, however, much improved the overall statistical association of the socio-economic variables with dengue incidence and reconciled the incongruous difference between the spatial hotspots and the SE risk factors. Our study suggests that incorporating transport networks enables a more real-world analysis within urban areas and should enable improvements in the identification of risk factors.
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Affiliation(s)
- Bertrand Lefebvre
- French Institute of Pondicherry, UMIFRE 21 CNRS-MEAE, Pondicherry 605001, India
| | - Rojina Karki
- CNRS, ARENES—UMR 6051, EHESP, Université de Rennes, 35000 Rennes, France
| | | | - Kanchana Nakhapakorn
- Faculty of Environment and Resource Studies, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand
| | - Eric Daudé
- CNRS, UMR 6266 IDEES, 7 rue Thomas Becket, 76821 Rouen, France
| | - Richard E. Paul
- Institut Pasteur, Université de Paris, CNRS, UMR 2000, Unité de Génétique Fonctionnelle des Maladies Infectieuses, 75015 Paris, France
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Shattuck EC. Networks, cultures, and institutions: Toward a social immunology. Brain Behav Immun Health 2021; 18:100367. [PMID: 34761241 PMCID: PMC8566934 DOI: 10.1016/j.bbih.2021.100367] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 10/08/2021] [Accepted: 10/08/2021] [Indexed: 12/26/2022] Open
Abstract
This paper calls for increased attention to the ways in which immune function – including its behavioral aspects – are responsive to social contexts at multiple levels. Psychoneuroimmunology has demonstrated that the quantity and quality of social connections can affect immune responses, while newer research is finding that sickness temporarily affects these same social networks and that some aspects of culture can potentially “get under the skin” to affect inflammatory responses. Social immunology, the research framework proposed here, unifies these findings and also considers the effects of structural factors – that is, a society's economic, political, and environmental landscape – on exposure to pathogens and subsequent immune responses. As the COVID-19 pandemic has highlighted, a holistic understanding of the effects of social contexts on the patterning of morbidity and mortality is critically important. Social immunology provides such a framework and can highlight important risk factors related to impaired immune function.
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Affiliation(s)
- Eric C Shattuck
- Institute for Health Disparities Research, University of Texas at San Antonio, San Antonio, TX, USA.,Department of Public Health, University of Texas at San Antonio, San Antonio, TX, USA
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Conceição GMDS, Barbosa GL, Lorenz C, Bocewicz ACD, Santana LMR, Marques CCDA, Chiaravalloti-Neto F. Effect of social isolation in dengue cases in the state of Sao Paulo, Brazil: An analysis during the COVID-19 pandemic. Travel Med Infect Dis 2021; 44:102149. [PMID: 34455075 DOI: 10.1016/j.tmaid.2021.102149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Studies have shown that human mobility is an important factor in dengue epidemiology. Changes in mobility resulting from COVID-19 pandemic set up a real-life situation to test this hypothesis. Our objective was to evaluate the effect of reduced mobility due to this pandemic in the occurrence of dengue in the state of São Paulo, Brazil. METHOD It is an ecological study of time series, developed between January and August 2020. We use the number of confirmed dengue cases and residential mobility, on a daily basis, from secondary information sources. Mobility was represented by the daily percentage variation of residential population isolation, obtained from the Google database. We modeled the relationship between dengue occurrence and social distancing by negative binomial regression, adjusted for seasonality. We represent the social distancing dichotomously (isolation versus no isolation) and consider lag for isolation from the dates of occurrence of dengue. RESULTS The risk of dengue decreased around 9.1% (95% CI: 14.2 to 3.7) in the presence of isolation, considering a delay of 20 days between the degree of isolation and the dengue first symptoms. CONCLUSIONS We have shown that mobility can play an important role in the epidemiology of dengue and should be considered in surveillance and control activities.
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Affiliation(s)
| | - Gerson Laurindo Barbosa
- Endemics Control Superintendence (SUCEN), Sao Paulo State Department of Health, Sao Paulo, Brazil
| | - Camila Lorenz
- Department of Epidemiology, School of Public Health, University of Sao Paulo, Sao Paulo, Brazil.
| | | | - Lidia Maria Reis Santana
- Epidemiological Surveillance Center "Professor Alexandre Vranjac" - Sao Paulo State Department of Health (CVE/SES-SP), Sao Paulo, Brazil; Federal University of São Paulo (UNIFESP), Sao Paulo, Brazil
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Schaber KL, Morrison AC, Elson WH, Astete-Vega H, Córdova-López JJ, Ríos López EJ, Flores WLQ, Santillan ASV, Scott TW, Waller LA, Kitron U, Barker CM, Perkins TA, Rothman AL, Vazquez-Prokopec GM, Elder JP, Paz-Soldan VA. The impact of dengue illness on social distancing and caregiving behavior. PLoS Negl Trop Dis 2021; 15:e0009614. [PMID: 34280204 PMCID: PMC8354465 DOI: 10.1371/journal.pntd.0009614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/10/2021] [Accepted: 06/30/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Human mobility among residential locations can drive dengue virus (DENV) transmission dynamics. Recently, it was shown that individuals with symptomatic DENV infection exhibit significant changes in their mobility patterns, spending more time at home during illness. This change in mobility is predicted to increase the risk of acquiring infection for those living with or visiting the ill individual. It has yet to be considered, however, whether social contacts are also changing their mobility, either by socially distancing themselves from the infectious individual or increasing contact to help care for them. Social, or physical, distancing and caregiving could have diverse yet important impacts on DENV transmission dynamics; therefore, it is necessary to better understand the nature and frequency of these behaviors including their effect on mobility. METHODOLOGY AND PRINCIPAL FINDINGS Through community-based febrile illness surveillance and RT-PCR infection confirmation, 67 DENV positive (DENV+) residents were identified in the city of Iquitos, Peru. Using retrospective interviews, data were collected on visitors and home-based care received during the illness. While 15% of participants lost visitors during their illness, 22% gained visitors; overall, 32% of all individuals (particularly females) received visitors while symptomatic. Caregiving was common (90%), particularly caring by housemates (91%) and caring for children (98%). Twenty-eight percent of caregivers changed their behavior enough to have their work (and, likely, mobility patterns) affected. This was significantly more likely when caring for individuals with low "health-related quality of well-being" during illness (Fisher's Exact, p = 0.01). CONCLUSIONS/SIGNIFICANCE Our study demonstrates that social contacts of individuals with dengue modify their patterns of visitation and caregiving. The observed mobility changes could impact a susceptible individual's exposure to virus or a presymptomatic/clinically inapparent individual's contribution to onward transmission. Accounting for changes in social contact mobility is imperative in order to get a more accurate understanding of DENV transmission.
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Affiliation(s)
- Kathryn L. Schaber
- Program of Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia, United States of America
| | - Amy C. Morrison
- Department of Virology and Emerging Infections, U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Peru
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - William H. Elson
- Department of Entomology and Nematology, University of California, Davis, California, United States of America
| | - Helvio Astete-Vega
- Department of Virology and Emerging Infections, U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Peru
| | - Jhonny J. Córdova-López
- Department of Entomology and Nematology, University of California, Davis, California, United States of America
| | - Esther Jennifer Ríos López
- Department of Virology and Emerging Infections, U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Peru
| | - W. Lorena Quiroz Flores
- Department of Virology and Emerging Infections, U.S. Naval Medical Research Unit No. 6, Lima and Iquitos, Peru
| | | | - Thomas W. Scott
- Department of Entomology and Nematology, University of California, Davis, California, United States of America
| | - Lance A. Waller
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Christopher M. Barker
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - T. Alex Perkins
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Alan L. Rothman
- Institute for Immunology and Informatics and Department of Cell and Molecular Biology, University of Rhode Island, Providence, Rhode Island, United States of America
| | - Gonzalo M. Vazquez-Prokopec
- Program of Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia, United States of America
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - John P. Elder
- School of Public Health, San Diego State University, San Diego, California, United States of America
| | - Valerie A. Paz-Soldan
- Department of Global Community Health and Behavioral Sciences, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
- * E-mail:
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8
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Elson WH, Reiner RC, Siles C, Bazan I, Vilcarromero S, Riley-Powell AR, Kawiecki AB, Astete H, Hontz RD, Barker CM, Vazquez-Prokopec GM, Morrison AC, Scott TW, Elder JP, Rothman AL, Paz-Soldan VA. Heterogeneity of Dengue Illness in Community-Based Prospective Study, Iquitos, Peru. Emerg Infect Dis 2021; 26:2077-2086. [PMID: 32818402 PMCID: PMC7454099 DOI: 10.3201/eid2609.191472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Measuring heterogeneity of dengue illness is necessary to define suitable endpoints in dengue vaccine and therapeutic trials and will help clarify behavioral responses to illness. To quantify heterogeneity in dengue illness, including milder cases, we developed the Dengue Illness Perceptions Response (IPR) survey, which captured detailed symptom data, including intensity, duration, and character, and change in routine activities caused by illness. During 2016–2019, we collected IPR data daily during the acute phase of illness for 79 persons with a positive reverse transcription PCR result for dengue virus RNA. Most participants had mild ambulatory disease. However, we measured substantial heterogeneity in illness experience, symptom duration, and maximum reported intensity of individual symptoms. Symptom intensity was a more valuable predicter of major activity change during dengue illness than symptom presence or absence alone. These data suggest that the IPR measures clinically useful heterogeneity in dengue illness experience and its relation to altered human behavior.
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9
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Morrison AC, Schwarz J, Mckenney JL, Cordova J, Rios JE, Quiroz WL, Vizcarra SA, Sopheab H, Bauer KM, Chhea C, Saphonn V, Hontz RD, Gorbach PM, Paz-Soldan VA. Potential for community based surveillance of febrile diseases: Feasibility of self-administered rapid diagnostic tests in Iquitos, Peru and Phnom Penh, Cambodia. PLoS Negl Trop Dis 2021; 15:e0009307. [PMID: 33901172 PMCID: PMC8101991 DOI: 10.1371/journal.pntd.0009307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 05/06/2021] [Accepted: 03/12/2021] [Indexed: 11/18/2022] Open
Abstract
Rapid diagnostic tests (RDTs) have the potential to identify infectious diseases quickly, minimize disease transmission, and could complement and improve surveillance and control of infectious and vector-borne diseases during outbreaks. The U.S. Defense Threat Reduction Agency's Joint Science and Technology Office (DTRA-JSTO) program set out to develop novel point-of-need RDTs for infectious diseases and deploy them for home use with no training. The aim of this formative study was to address two questions: 1) could community members in Iquitos, Peru and Phnom Penh, Cambodia competently use RDTs of different levels of complexity at home with visually based instructions provided, and 2) if an RDT were provided at no cost, would it be used at home if family members displayed febrile symptoms? Test kits with written and video (Peru only) instructions were provided to community members (Peru [n = 202]; Cambodia [n = 50]) or community health workers (Cambodia [n = 45]), and trained observers evaluated the competency level for each of the several steps required to successfully operate one of two multiplex RDTs on themselves or other consenting participant (i.e., family member). In Iquitos, >80% of residents were able to perform 11/12 steps and 7/15 steps for the two- and five-pathogen test, respectively. Competency in Phnom Penh never reached 80% for any of the 12 or 15 steps for either test; the percentage of participants able to perform a step ranged from 26-76% and 23-72%, for the two- and five-pathogen tests, respectively. Commercially available NS1 dengue rapid tests were distributed, at no cost, to households with confirmed exposure to dengue or Zika virus; of 14 febrile cases reported, six used the provided RDT. Our findings support the need for further implementation research on the appropriate level of instructions or training needed for diverse devices in different settings, as well as how to best integrate RDTs into existing local public health and disease surveillance programs at a large scale.
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Affiliation(s)
- Amy C Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
- U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
| | - Julia Schwarz
- Icahn School of Medicine at Mt Sinai, New York, New York, United States of America
| | - Jennie L Mckenney
- University of California Fielding School of Public Health, Los Angeles, California, United States of America
| | - Jhonny Cordova
- Department of Entomology and Nematology, University of California, Davis, California, United States of America
| | - Jennifer E Rios
- U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
| | - W Lorena Quiroz
- U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
| | - S Alfonso Vizcarra
- Department of Entomology and Nematology, University of California, Davis, California, United States of America
| | - Heng Sopheab
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Karin M Bauer
- Tulane School of Public Health and Tropical Medicine, New Orleans, Lousiana, United States of America
- University of Washington, Seattle, Washington, United States of America
| | - Chhorvann Chhea
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | | | - Robert D Hontz
- U.S. Naval Medical Research Unit No. 6 (NAMRU-6), Lima, Peru
- U.S. Naval Medical Research Unit No. 2 (NAMRU-2), Singapore
| | - Pamina M Gorbach
- University of California Fielding School of Public Health, Los Angeles, California, United States of America
| | - Valerie A Paz-Soldan
- Tulane School of Public Health and Tropical Medicine, New Orleans, Lousiana, United States of America
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10
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Reconstructing unseen transmission events to infer dengue dynamics from viral sequences. Nat Commun 2021; 12:1810. [PMID: 33753725 PMCID: PMC7985522 DOI: 10.1038/s41467-021-21888-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 02/18/2021] [Indexed: 11/18/2022] Open
Abstract
For most pathogens, transmission is driven by interactions between the behaviours of infectious individuals, the behaviours of the wider population, the local environment, and immunity. Phylogeographic approaches are currently unable to disentangle the relative effects of these competing factors. We develop a spatiotemporally structured phylogenetic framework that addresses these limitations by considering individual transmission events, reconstructed across spatial scales. We apply it to geocoded dengue virus sequences from Thailand (N = 726 over 18 years). We find infected individuals spend 96% of their time in their home community compared to 76% for the susceptible population (mainly children) and 42% for adults. Dynamic pockets of local immunity make transmission more likely in places with high heterotypic immunity and less likely where high homotypic immunity exists. Age-dependent mixing of individuals and vector distributions are not important in determining spread. This approach provides previously unknown insights into one of the most complex disease systems known and will be applicable to other pathogens. Phylogeographic analyses can provide broad descriptions of the spread of pathogens between populations, but are limited by incomplete sampling. Here, the authors develop an inference framework that reconstructs sequential transmission events and use it to characterise dynamics of dengue in Thailand.
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11
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Schaber KL, Perkins TA, Lloyd AL, Waller LA, Kitron U, Paz-Soldan VA, Elder JP, Rothman AL, Civitello DJ, Elson WH, Morrison AC, Scott TW, Vazquez-Prokopec GM. Disease-driven reduction in human mobility influences human-mosquito contacts and dengue transmission dynamics. PLoS Comput Biol 2021; 17:e1008627. [PMID: 33465065 PMCID: PMC7845972 DOI: 10.1371/journal.pcbi.1008627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 01/29/2021] [Accepted: 12/11/2020] [Indexed: 02/01/2023] Open
Abstract
Heterogeneous exposure to mosquitoes determines an individual’s contribution to vector-borne pathogen transmission. Particularly for dengue virus (DENV), there is a major difficulty in quantifying human-vector contacts due to the unknown coupled effect of key heterogeneities. To test the hypothesis that the reduction of human out-of-home mobility due to dengue illness will significantly influence population-level dynamics and the structure of DENV transmission chains, we extended an existing modeling framework to include social structure, disease-driven mobility reductions, and heterogeneous transmissibility from different infectious groups. Compared to a baseline model, naïve to human pre-symptomatic infectiousness and disease-driven mobility changes, a model including both parameters predicted an increase of 37% in the probability of a DENV outbreak occurring; a model including mobility change alone predicted a 15.5% increase compared to the baseline model. At the individual level, models including mobility change led to a reduction of the importance of out-of-home onward transmission (R, the fraction of secondary cases predicted to be generated by an individual) by symptomatic individuals (up to -62%) at the expense of an increase in the relevance of their home (up to +40%). An individual’s positive contribution to R could be predicted by a GAM including a non-linear interaction between an individual’s biting suitability and the number of mosquitoes in their home (>10 mosquitoes and 0.6 individual attractiveness significantly increased R). We conclude that the complex fabric of social relationships and differential behavioral response to dengue illness cause the fraction of symptomatic DENV infections to concentrate transmission in specific locations, whereas asymptomatic carriers (including individuals in their pre-symptomatic period) move the virus throughout the landscape. Our findings point to the difficulty of focusing vector control interventions reactively on the home of symptomatic individuals, as this approach will fail to contain virus propagation by visitors to their house and asymptomatic carriers. Human mobility patterns can play an integral role in vector-borne disease dynamics by characterizing an individual’s potential contacts with disease-transmitting vectors. Dengue virus is transmitted by a sedentary vector, but human mobility allows individuals to have contact with mosquitoes at their home and other houses they frequent (their activity space). When accounting for the decreased mobility of symptomatic dengue cases in an agent-based simulation model, however, we found a severely diminished role of the activity space in onward transmission. Those who received the majority of their mosquito contacts outside their home experienced decreases in expected bites and onward transmission when mobility changes were accounted for. Onward transmission was driven by a synergistic relationship between the number of mosquitoes in an individual’s home and their biting suitability, where even those with the highest biting suitability would have limited contribution to transmission given a low number of household mosquitoes. Reactive vector control, which often targets symptomatic cases, could be effective for slowing onward transmission from these cases, but will fail to control virus transmission due to the disproportionate contribution of asymptomatic infections.
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Affiliation(s)
- Kathryn L. Schaber
- Program of Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia, United States of America
| | - T. Alex Perkins
- Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Alun L. Lloyd
- Biomathematics Graduate Program and Department of Mathematics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Lance A. Waller
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Valerie A. Paz-Soldan
- Department of Global Community Health and Behavioral Sciences, Tulane School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
| | - John P. Elder
- Graduate School of Public Health, San Diego State University, San Diego, California, United States of America
| | - Alan L. Rothman
- Institute for Immunology and Informatics and Department of Cell and Molecular Biology, University of Rhode Island, Providence, Rhode Island, United States of America
| | - David J. Civitello
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - William H. Elson
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Amy C. Morrison
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Thomas W. Scott
- Department of Entomology and Nematology, University of California Davis, Davis, California, United States of America
| | - Gonzalo M. Vazquez-Prokopec
- Program of Population Biology, Ecology and Evolution, Emory University, Atlanta, Georgia, United States of America
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
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12
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Kirstein OD, Ayora-Talavera G, Koyoc-Cardeña E, Chan Espinoza D, Che-Mendoza A, Cohuo-Rodriguez A, Granja-Pérez P, Puerta-Guardo H, Pavia-Ruz N, Dunbar MW, Manrique-Saide P, Vazquez-Prokopec GM. Natural arbovirus infection rate and detectability of indoor female Aedes aegypti from Mérida, Yucatán, Mexico. PLoS Negl Trop Dis 2021; 15:e0008972. [PMID: 33395435 PMCID: PMC7781390 DOI: 10.1371/journal.pntd.0008972] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/10/2020] [Indexed: 12/03/2022] Open
Abstract
Arbovirus infection in Aedes aegypti has historically been quantified from a sample of the adult population by pooling collected mosquitoes to increase detectability. However, there is a significant knowledge gap about the magnitude of natural arbovirus infection within areas of active transmission, as well as the sensitivity of detection of such an approach. We used indoor Ae. aegypti sequential sampling with Prokopack aspirators to collect all mosquitoes inside 200 houses with suspected active ABV transmission from the city of Mérida, Mexico, and tested all collected specimens by RT-PCR to quantify: a) the absolute arbovirus infection rate in individually tested Ae. aegypti females; b) the sensitivity of using Prokopack aspirators in detecting ABV-infected mosquitoes; and c) the sensitivity of entomological inoculation rate (EIR) and vectorial capacity (VC), two measures ABV transmission potential, to different estimates of indoor Ae. aegypti abundance. The total number of Ae. aegypti (total catch, the sum of all Ae. aegypti across all collection intervals) as well as the number on the first 10-min of collection (sample, equivalent to a routine adult aspiration session) were calculated. We individually tested by RT-PCR 2,161 Aedes aegypti females and found that 7.7% of them were positive to any ABV. Most infections were CHIKV (77.7%), followed by DENV (11.4%) and ZIKV (9.0%). The distribution of infected Aedes aegypti was overdispersed; 33% houses contributed 81% of the infected mosquitoes. A significant association between ABV infection and Ae. aegypti total catch indoors was found (binomial GLMM, Odds Ratio > 1). A 10-min indoor Prokopack collection led to a low sensitivity of detecting ABV infection (16.3% for detecting infected mosquitoes and 23.4% for detecting infected houses). When averaged across all infested houses, mean EIR ranged between 0.04 and 0.06 infective bites per person per day, and mean VC was 0.6 infectious vectors generated from a population feeding on a single infected host per house/day. Both measures were significantly and positively associated with Ae. aegypti total catch indoors. Our findings provide evidence that the accurate estimation and quantification of arbovirus infection rate and transmission risk is a function of the sampling effort, the local abundance of Aedes aegypti and the intensity of arbovirus circulation. Aedes-borne diseases comprise a serious public health burden in many parts of the world, usually affecting low income areas. The ability to detect virus circulation within a population may be key in responding to the threat of outbreaks, providing a cost-effective approach for triggering vector control. Unfortunately, gaps in the knowledge of natural Aedes-borne virus (ABV) infection in Aedes aegypti have led to uncertainties in the consideration of arbovirus surveillance in mosquitoes. Here, we show that the natural infection rate in a mosquito population may not be a function of where Aedes aegypti are, but rather where key human-mosquito contacts occur. Sampling 200 houses with suspected ABV active transmission led us to quantify high virus infection rates in all Aedes aegypti present in the house and use such information to estimate the sensitivity of indoor aspiration with Prokopack devices and two measures of ABV transmission potential. Our findings provide evidence that the accurate quantification of arbovirus infection rate and transmission risk is a function of the sampling effort, the local abundance of Aedes aegypti and the intensity of arbovirus circulation. Results from this study are relevant to understand the value of virus testing of vector populations, and for the design of entomological endpoints relevant for epidemiological trials quantifying the impact of vector control on ABVs.
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Affiliation(s)
- Oscar David Kirstein
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Guadalupe Ayora-Talavera
- Laboratorio de Virología. Centro de Investigaciones Regionales “Dr. Hideyo Noguchi”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Edgar Koyoc-Cardeña
- Unidad Colaborativa de Bioensayos Entomológicos, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Daniel Chan Espinoza
- Unidad Colaborativa de Bioensayos Entomológicos, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Azael Che-Mendoza
- Unidad Colaborativa de Bioensayos Entomológicos, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Azael Cohuo-Rodriguez
- Unidad Colaborativa de Bioensayos Entomológicos, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Pilar Granja-Pérez
- Laboratorio Estatal de Salud Pública, Servicios de Salud de Yucatán, Mérida, Yucatán, México
| | - Henry Puerta-Guardo
- Unidad Colaborativa de Bioensayos Entomológicos, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Norma Pavia-Ruz
- Laboratorio de Hematología. Centro de Investigaciones Regionales “Dr. Hideyo Noguchi”, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
| | - Mike W. Dunbar
- Department of Environmental Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Pablo Manrique-Saide
- Unidad Colaborativa de Bioensayos Entomológicos, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
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13
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Núñez-López M, Alarcón Ramos L, Velasco-Hernández JX. Migration rate estimation in an epidemic network. APPLIED MATHEMATICAL MODELLING 2021; 89:1949-1964. [PMID: 32952269 PMCID: PMC7486824 DOI: 10.1016/j.apm.2020.08.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 05/07/2023]
Abstract
Most of the recent epidemic outbreaks in the world have as a trigger, a strong migratory component as has been evident in the recent Covid-19 pandemic. In this work we address the problem of migration of human populations and its effect on pathogen reinfections in the case of Dengue, using a Markov-chain susceptible-infected-susceptible (SIS) metapopulation model over a network. Our model postulates a general contact rate that represents a local measure of several factors: the population size of infected hosts that arrive at a given location as a function of total population size, the current incidence at neighboring locations, and the connectivity of the network where the disease spreads. This parameter can be interpreted as an indicator of outbreak risk at a given location. This parameter is tied to the fraction of individuals that move across boundaries (migration). To illustrate our model capabilities, we estimate from epidemic Dengue data in Mexico the dynamics of migration at a regional scale incorporating climate variability represented by an index based on precipitation data.
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Affiliation(s)
- M Núñez-López
- Department of Mathematics, ITAM Río Hondo 1, Ciudad de México 01080, México
| | - L Alarcón Ramos
- Departamento de Matemáticas Aplicadas y Sistemas, Universidad Autónoma Metropolitana, Cuajimalpa, Av. Vasco de Quiroga 4871, Cuajimalpa de Morelos, 05300, México
| | - J X Velasco-Hernández
- Instituto de Matemáticas, Universidad Nacional Autónoma de México, Boulevard Juriquilla No. 3001, Juriquilla, 76230, México
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14
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Schaber KL, Paz-Soldan VA, Morrison AC, Elson WHD, Rothman AL, Mores CN, Astete-Vega H, Scott TW, Waller LA, Kitron U, Elder JP, Barker CM, Perkins TA, Vazquez-Prokopec GM. Correction: Dengue illness impacts daily human mobility patterns in Iquitos, Peru. PLoS Negl Trop Dis 2020; 14:e0008348. [PMID: 32479492 PMCID: PMC7272095 DOI: 10.1371/journal.pntd.0008348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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