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Vollans M, Day J, Cant S, Hood J, Kilpatrick AM, Kramer LD, Vaux A, Medlock J, Ward T, Paton RS. Modelling the temperature dependent extrinsic incubation period of West Nile Virus using Bayesian time delay models. J Infect 2024:106296. [PMID: 39343246 DOI: 10.1016/j.jinf.2024.106296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2024] [Accepted: 09/23/2024] [Indexed: 10/01/2024]
Abstract
West Nile Virus (WNV) is a mosquito-borne pathogen that primarily infects birds. Infections can spillover to humans and cause a spectrum of clinical symptoms, including WNV neuroinvasive disease. The extrinsic incubation period (EIP) is the time taken for a mosquito to become infectious following the ingestion of an infected blood meal. Characterising how the EIP varies with temperature is an essential part of predicting the impact and transmission dynamics of WNV. We re-analyse existing experimental data using Bayesian time delay models, allowing us to account for variation in how quickly individual mosquitoes become infectious with WNV. In these experiments, cohorts of Culex pipiens mosquitoes were infected with WNV and kept under different temperature conditions, being checked for disseminated infection at defined timepoints. We find that EIPs are best described with a Weibull distribution and become shorter log-linearly with temperature. Under 18ºC, less than 1% of infected Cx. pipiens had a disseminated infection after 5 days, compared to 9.73% (95% CrI: 7.97 to 11.54) at 25ºC and 42.20% (95% CrI: 38.32 to 46.60) at 30ºC. In the hottest experimental temperature treatment (32ºC), the EIP50 was estimated at 3.78 days (CrI: 3.42 to 4.15) compared to over 100 days in the coolest treatment (15ºC). The variance of EIPs was found to be much larger at lower temperatures than higher temperatures, highlighting the importance of characterising the time delay distribution associated with the EIP. We additionally demonstrate a competitive advantage of WNV strain WN02 over NY99, where the former infects mosquitoes more quickly at colder temperature than the latter. This research contributes crucial parameters to the WNV literature, providing essential insights for modellers and those planning interventions.
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Affiliation(s)
- Maisie Vollans
- Infectious Disease Modelling Team, All Hazards Intelligence, DAS, UKHSA
| | - Julie Day
- Infectious Disease Modelling Team, All Hazards Intelligence, DAS, UKHSA
| | - Susie Cant
- Infectious Disease Modelling Team, All Hazards Intelligence, DAS, UKHSA
| | - Jordan Hood
- STOR-i Centre for Doctoral Training, Lancaster University; Infectious Disease Modelling Team, All Hazards Intelligence, DAS, UKHSA
| | - A Marm Kilpatrick
- Department of Ecology and Evolutionary Biology, University of California
| | - Laura D Kramer
- School of Public Health, State University of New York Albany
| | - Alexander Vaux
- Medical Entomology and Zoonoses Ecology, Centre for Climate and Health Security, UKHSA
| | - Jolyon Medlock
- Medical Entomology and Zoonoses Ecology, Centre for Climate and Health Security, UKHSA
| | - Thomas Ward
- Infectious Disease Modelling Team, All Hazards Intelligence, DAS, UKHSA
| | - Robert S Paton
- Infectious Disease Modelling Team, All Hazards Intelligence, DAS, UKHSA.
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2
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Viral agents (2nd section). Transfusion 2024; 64 Suppl 1:S19-S207. [PMID: 38394038 DOI: 10.1111/trf.17630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Accepted: 12/02/2023] [Indexed: 02/25/2024]
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Kuno G. Mechanisms of Yellow Fever Transmission: Gleaning the Overlooked Records of Importance and Identifying Problems, Puzzles, Serious Issues, Surprises and Research Questions. Viruses 2024; 16:84. [PMID: 38257784 PMCID: PMC10820296 DOI: 10.3390/v16010084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/12/2023] [Accepted: 12/29/2023] [Indexed: 01/24/2024] Open
Abstract
In viral disease research, few diseases can compete with yellow fever for the volume of literature, historical significance, richness of the topics and the amount of strong interest among both scientists and laypersons. While the major foci of viral disease research shifted to other more pressing new diseases in recent decades, many critically important basic tasks still remain unfinished for yellow fever. Some of the examples include the mechanisms of transmission, the process leading to outbreak occurrence, environmental factors, dispersal, and viral persistence in nature. In this review, these subjects are analyzed in depth, based on information not only in old but in modern literatures, to fill in blanks and to update the current understanding on these topics. As a result, many valuable facts, ideas, and other types of information that complement the present knowledge were discovered. Very serious questions about the validity of the arbovirus concept and some research practices were also identified. The characteristics of YFV and its pattern of transmission that make this virus unique among viruses transmitted by Ae. aegypti were also explored. Another emphasis was identification of research questions. The discovery of a few historical surprises was an unexpected benefit.
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Affiliation(s)
- Goro Kuno
- Formerly at the Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA
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4
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Giovanetti M, Pinotti F, Zanluca C, Fonseca V, Nakase T, Koishi AC, Tscha M, Soares G, Dorl GG, Marques AEM, Sousa R, Adelino TER, Xavier J, de Oliveira C, Patroca S, Guimaraes NR, Fritsch H, Mares-Guia MA, Levy F, Passos PH, da Silva VL, Pereira LA, Mendonça AF, de Macêdo IL, Ribeiro de Sousa DE, Rodrigues de Toledo Costa G, Botelho de Castro M, de Souza Andrade M, de Abreu FVS, Campos FS, Iani FCDM, Pereira MA, Cavalcante KRLJ, de Freitas ARR, Campelo de Albuquerque CF, Macário EM, dos Anjos MPD, Ramos RC, Campos AAS, Pinter A, Chame M, Abdalla L, Riediger IN, Ribeiro SP, Bento AI, de Oliveira T, Freitas C, Oliveira de Moura NF, Fabri A, dos Santos Rodrigues CD, Dos Santos CC, Barreto de Almeida MA, dos Santos E, Cardoso J, Augusto DA, Krempser E, Mucci LF, Gatti RR, Cardoso SF, Fuck JAB, Lopes MGD, Belmonte IL, Mayoral Pedroso da Silva G, Soares MRF, de Castilhos MDMS, de Souza e Silva JC, Bisetto Junior A, Pouzato EG, Tanabe LS, Arita DA, Matsuo R, dos Santos Raymundo J, Silva PCL, Santana Araújo Ferreira Silva A, Samila S, Carvalho G, Stabeli R, Navegantes W, Moreira LA, Ferreira AGA, Pinheiro GG, Nunes BTD, de Almeida Medeiros DB, Cruz ACR, Venâncio da Cunha R, Van Voorhis W, Bispo de Filippis AM, Almiron M, Holmes EC, Ramos DG, Romano A, Lourenço J, Alcantara LCJ, Duarte dos Santos CN. Genomic epidemiology unveils the dynamics and spatial corridor behind the Yellow Fever virus outbreak in Southern Brazil. SCIENCE ADVANCES 2023; 9:eadg9204. [PMID: 37656782 PMCID: PMC10854437 DOI: 10.1126/sciadv.adg9204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 07/26/2023] [Indexed: 09/03/2023]
Abstract
Despite the considerable morbidity and mortality of yellow fever virus (YFV) infections in Brazil, our understanding of disease outbreaks is hampered by limited viral genomic data. Here, through a combination of phylogenetic and epidemiological models, we reconstructed the recent transmission history of YFV within different epidemic seasons in Brazil. A suitability index based on the highly domesticated Aedes aegypti was able to capture the seasonality of reported human infections. Spatial modeling revealed spatial hotspots with both past reporting and low vaccination coverage, which coincided with many of the largest urban centers in the Southeast. Phylodynamic analysis unraveled the circulation of three distinct lineages and provided proof of the directionality of a known spatial corridor that connects the endemic North with the extra-Amazonian basin. This study illustrates that genomics linked with eco-epidemiology can provide new insights into the landscape of YFV transmission, augmenting traditional approaches to infectious disease surveillance and control.
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Affiliation(s)
- Marta Giovanetti
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Instituto Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Department of Science and Technology for Humans and the Environment, Università of Campus Bio-Medico di Roma, Italy
| | | | - Camila Zanluca
- Laboratório de Virologia Molecular, Instituto Carlos Chagas/Fiocruz-PR, Curitiba, Paraná, Brazil
| | - Vagner Fonseca
- Organização Pan-Americana da Saúde/Organização Mundial da Saúde, Brasília, Distrito Federal, Brazil
| | - Taishi Nakase
- Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7BN, UK
| | - Andrea C. Koishi
- Laboratório de Virologia Molecular, Instituto Carlos Chagas/Fiocruz-PR, Curitiba, Paraná, Brazil
| | - Marcel Tscha
- Laboratório de Virologia Molecular, Instituto Carlos Chagas/Fiocruz-PR, Curitiba, Paraná, Brazil
| | - Guilherme Soares
- Laboratório de Virologia Molecular, Instituto Carlos Chagas/Fiocruz-PR, Curitiba, Paraná, Brazil
| | - Gisiane Gruber Dorl
- Laboratório de Virologia Molecular, Instituto Carlos Chagas/Fiocruz-PR, Curitiba, Paraná, Brazil
| | | | - Renato Sousa
- Laboratório de Patologia Veterinária, Hospital Veterinário UFPR, PR Brazil
| | - Talita Emile Ribeiro Adelino
- Laboratório Central de Saúde Pública do Estado de Minas Gerais, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | - Joilson Xavier
- Instituto Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Carla de Oliveira
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Instituto Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | | | - Natalia Rocha Guimaraes
- Laboratório Central de Saúde Pública do Estado de Minas Gerais, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | - Hegger Fritsch
- Instituto Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Flavia Levy
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Pedro Henrique Passos
- Coordenação Geral das Arboviroses, Secretaria de Vigilância em Saúde/Ministério da Saúde (CGARB/SVS-MS), Brasília, Distrito Federal, Brazil
| | | | - Luiz Augusto Pereira
- Laboratório Central de Saúde Pública Dr Giovanni Cysneiros, Goiânia, Goiás, Brazil
| | - Ana Flávia Mendonça
- Laboratório Central de Saúde Pública Dr Giovanni Cysneiros, Goiânia, Goiás, Brazil
| | - Isabel Luana de Macêdo
- Veterinary Pathology Laboratory, Campus Darcy Ribeiro, University of Brasília, Brasília, DF 70636- 200, Brazil
| | | | | | - Marcio Botelho de Castro
- Veterinary Pathology Laboratory, Campus Darcy Ribeiro, University of Brasília, Brasília, DF 70636- 200, Brazil
- Graduate Program in Animal Sciences, College of Agronomy and Veterinary Medicine, University of Brasília, Brasília, DF 70910-900, Brazil
| | - Miguel de Souza Andrade
- Baculovirus Laboratory, Department of Cell Biology, Institute of Biological Sciences, University of Brasilia, Brasília 70910-900, DF, Brazil
| | | | - Fabrício Souza Campos
- Institute of Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre 90035-003, RS, Brazil
| | - Felipe Campos de Melo Iani
- Laboratório Central de Saúde Pública do Estado de Minas Gerais, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | - Maira Alves Pereira
- Laboratório Central de Saúde Pública do Estado de Minas Gerais, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | | | | | | | | | - Marlei Pickler Debiasi dos Anjos
- Laboratorio central de Saude Publica de Santa Catarina, Superintendência de Vigilância em Saúde – SES – Santa Catarina, South Brazil
| | - Rosane Campanher Ramos
- Laboratório Central de Saúde Pública do Estado do Rio Grande do Sul, Superintendência de Vigilância em Saúde – SES – Santa Catarina, South Brazil
| | | | - Adriano Pinter
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, 05508-000, Brazil
| | - Marcia Chame
- Oswaldo Cruz Foundation, Biodiversity, Wildlife Health Institutional Platform (PIBSS/Fiocruz), Rio de Janeiro, Brazil
| | - Livia Abdalla
- Oswaldo Cruz Foundation, Biodiversity, Wildlife Health Institutional Platform (PIBSS/Fiocruz), Rio de Janeiro, Brazil
| | | | - Sérvio Pontes Ribeiro
- Laboratory of Ecology of Diseases & Forests, NUPEB/ICEB, Federal University of Ouro Preto, Minas Gerais, Brazil
| | - Ana I. Bento
- Pandemic Prevention Initiative, The Rockefeller Foundation, Washington DC, USA
| | - Tulio de Oliveira
- School for Data Science and Computational Thinking, Faculty of Science and Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Carla Freitas
- Secretaria de Vigilância em Saúde, SVS, Brazilian Ministry of Health, Brasilia, Federal District, Brazil
| | | | - Allison Fabri
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | | | | | | | - Edmilson dos Santos
- Secretaria Estadual de Saúde do Rio Grande do Sul, Centro Estadual de Vigilância em Saúde, Porto Alegre, RS, Brazil
| | - Jader Cardoso
- Secretaria Estadual de Saúde do Rio Grande do Sul, Centro Estadual de Vigilância em Saúde, Porto Alegre, RS, Brazil
| | - Douglas Adriano Augusto
- Plataforma Institucional Biodiversidade e Saúde Silvestre - Centro de Informação em Saúde Silvestre (CISS) - Fiocruz/RJ, Avenida Brasil, 4365. Manguinhos - Rio de Janeiro - RJ Cep: 21.040-360
| | - Eduardo Krempser
- Plataforma Institucional Biodiversidade e Saúde Silvestre - Centro de Informação em Saúde Silvestre (CISS) - Fiocruz/RJ, Avenida Brasil, 4365. Manguinhos - Rio de Janeiro - RJ Cep: 21.040-360
| | - Luís Filipe Mucci
- Secretaria da Saúde (São Paulo - Estado), Av Dr. Enéas Carvalho de Aguiar, 188 - Cerqueira César, São Paulo - SP, 05403-000, Brazil
- Coordenadoria de Controle de Doenças (CCD), Av. Dr. Enéas Carvalho de Aguiar, 188 - Cerqueira César, São Paulo - SP, 05403-000, Brazil
- Instituto Pasteur (IP), Av. Paulista, 363 Cerqueira Cesar – São Paulo- SP – CEP:01311-000
| | - Renata Rispoli Gatti
- Secretaria de Estado da Saude de Santa Catarina, R. Esteves Júnior, 160 - Centro, Florianópolis - SC, 88015-130, Brazil
| | - Sabrina Fernandes Cardoso
- Secretaria de Estado da Saude de Santa Catarina, R. Esteves Júnior, 160 - Centro, Florianópolis - SC, 88015-130, Brazil
- Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina (UFSC), Florianópolis, Brazil
| | - João Augusto Brancher Fuck
- Diretoria de Vigilância Epidemiológica da Secretaria de Estado da Saúde de Santa Catarina, R. Esteves Júnior, 160 - Centro, Florianópolis - SC, 88015-130, Brazil
| | - Maria Goretti David Lopes
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | - Ivana Lucia Belmonte
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | | | | | | | | | - Alceu Bisetto Junior
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | - Emanuelle Gemin Pouzato
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | - Laurina Setsuko Tanabe
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | - Daniele Akemi Arita
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | - Ricardo Matsuo
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | | | | | | | - Sandra Samila
- Secretaria de Estado da Saúde do Paraná, Brazil, R. Piquiri, 170 - Rebouças, Curitiba - PR, 80230-140
| | - Glauco Carvalho
- Laboratório Central de Saúde Pública do Estado de Minas Gerais, Fundação Ezequiel Dias, Belo Horizonte, Minas Gerais, Brazil
| | - Rodrigo Stabeli
- Organização Pan-Americana da Saúde/Organização Mundial da Saúde, Brasília, Distrito Federal, Brazil
| | - Wildo Navegantes
- Organização Pan-Americana da Saúde/Organização Mundial da Saúde, Brasília, Distrito Federal, Brazil
| | - Luciano Andrade Moreira
- Mosquitos Vetores: Endossimbiontes e Interação Patógeno-Vetor, Instituto René Rachou–Fiocruz, Belo Horizonte 30190-002, MG, Brazil
| | - Alvaro Gil A. Ferreira
- Mosquitos Vetores: Endossimbiontes e Interação Patógeno-Vetor, Instituto René Rachou–Fiocruz, Belo Horizonte 30190-002, MG, Brazil
| | | | | | | | | | | | - Wes Van Voorhis
- Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, WA, USA
| | | | - Maria Almiron
- Pan American Health Organization/World Health Organization, Washington, DC, USA
| | - Edward C. Holmes
- Marie Bashir Institute for Infectious Diseases and Biosecurity, School of Life and Environmental Sciences and School of Medical Sciences, University of Sydney, Sydney, NSW, Australia
| | - Daniel Garkauskas Ramos
- Coordenação Geral das Arboviroses, Secretaria de Vigilância em Saúde/Ministério da Saúde (CGARB/SVS-MS), Brasília, Distrito Federal, Brazil
| | - Alessandro Romano
- Coordenação Geral das Arboviroses, Secretaria de Vigilância em Saúde/Ministério da Saúde (CGARB/SVS-MS), Brasília, Distrito Federal, Brazil
| | - José Lourenço
- BioISI (Biosystems and Integrative Sciences Institute), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa Portugal
| | - Luiz Carlos Junior Alcantara
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
- Instituto Rene Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
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Hale GL. Flaviviruses and the Traveler: Around the World and to Your Stage. A Review of West Nile, Yellow Fever, Dengue, and Zika Viruses for the Practicing Pathologist. Mod Pathol 2023; 36:100188. [PMID: 37059228 DOI: 10.1016/j.modpat.2023.100188] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 04/02/2023] [Accepted: 04/05/2023] [Indexed: 04/16/2023]
Abstract
Flaviviruses are a genus of single-stranded RNA viruses that impose an important and growing burden to human health. There are over 3 billion individuals living in areas where flaviviruses are endemic. Flaviviruses and their arthropod vectors (which include mosquitoes and ticks) take advantage of global travel to expand their distribution and cause severe disease in humans, and they can be grouped according to their vector and pathogenicity. The mosquito-borne flaviviruses cause a spectrum of diseases from encephalitis to hepatitis and vascular shock syndrome, congenital abnormalities, and fetal death. Neurotropic infections such as Zika virus and West Nile virus cross the blood-brain barrier and infect neurons and other cells, leading to meningoencephalitis. In the hemorrhagic fever clade, there are yellow fever virus, the prototypical hemorrhagic fever virus that infects hepatocytes, and dengue virus, which infects cells of the reticuloendothelial system and can lead to a dramatic plasma cell leakage and shock syndrome. Zika virus also causes congenital infections and fetal death and is the first and only example of a teratogenic arbovirus in humans. Diagnostic testing for flaviviruses broadly includes the detection of viral RNA in serum (particularly within the first 10 days of symptoms), viral isolation by cell culture (rarely performed due to complexity and biosafety concerns), and histopathologic evaluation with immunohistochemistry and molecular testing on formalin-fixed paraffin-embedded tissue blocks. This review focuses on 4 mosquito-borne flaviviruses-West Nile, yellow fever, dengue, and Zika virus-and discusses the mechanisms of transmission, the role of travel in geographic distribution and epidemic emergence, and the clinical and histopathologic features of each. Finally, prevention strategies such as vector control and vaccination are discussed.
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Affiliation(s)
- Gillian L Hale
- Department of Pathology, University of Utah, Salt Lake City, Utah.
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6
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Occurrence of yellow fever outbreaks in a partially vaccinated population: An analysis of the effective reproduction number. PLoS Negl Trop Dis 2022; 16:e0010741. [PMID: 36108073 PMCID: PMC9514630 DOI: 10.1371/journal.pntd.0010741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 09/27/2022] [Accepted: 08/13/2022] [Indexed: 11/19/2022] Open
Abstract
Background Yellow fever is endemic in Africa and the Americas, occurring in urban or sylvatic environments. The infection presents varying symptoms, with high case-fatality among severe cases. In 2016, Brazil had sylvatic yellow fever outbreaks with more than 11 thousand cases, predominantly affecting the country’s Southeast region. The state of Minas Gerais accounted for 30% of cases, even after the vaccine had been included in the immunization calendar for at least 30 years. Methodology and principal findings We applied parameters described in the literature from yellow fever disease into a compartmental model of vector-borne diseases, using namely generation time intervals, vital host and vector parameters, and force of infection, using macroregions as the spatial unit and epidemiological weeks as the time interval. The model permits obtaining the reproduction number, which we analyzed from reported cases of yellow fever from 2016 to 2018 in residents of the state of Minas Gerais, Brazil. Minas Gerais recorded two outbreak periods, starting in EW 51/2016 and EW 51/2017. Of all the reported cases (3,304), 57% were men 30 to 59 years of age. Approximately 27% of cases (905) were confirmed, and 22% (202) of these individuals died. The estimated effective reproduction number varied from 2.7 (95% CI: 2.0–3.6) to 7.2 (95% CI: 4.4–10.9], found in the Oeste and Nordeste regions, respectively. Vaccination coverage in children under one year of age showed heterogeneity among the municipalities comprising the macroregions. Conclusion The outbreaks in multiple parts of the state and the estimated Re values raise concern since the state population was partially vaccinated. Heterogeneity in vaccination coverage may have been associated with the occurrence of outbreaks in the first period, while the subsequent intense vaccination campaign may have determined lower Re values in the second period. Yellow fever attracts important research interest since it is an avoidable disease and is still recurrent in Brazil. Although the country has an important public policy that integrates production, distribution, and routine application of the yellow fever vaccine, the disease is still included on the list of endemic infectious diseases in some regions. Surprisingly, regions that were not previously part of risk areas for yellow fever were heavily affected by the outbreak from 2016 to 2018 in the country. Understanding the outbreak’s occurrence and intensity in the state of Minas Gerais based on the effective reproduction number, the focus of this article, is just part of the larger goal of defining with greater certainty the risk areas for yellow fever and proposing measures to control the spread of the disease.
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Medeiros-Sousa AR, Laporta GZ, Mucci LF, Marrelli MT. Epizootic dynamics of yellow fever in forest fragments: An agent-based model to explore the influence of vector and host parameters. Ecol Modell 2022. [DOI: 10.1016/j.ecolmodel.2022.109884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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8
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Servadio JL, Muñoz-Zanzi C, Convertino M. Environmental determinants predicting population vulnerability to high yellow fever incidence. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220086. [PMID: 35316947 PMCID: PMC8889195 DOI: 10.1098/rsos.220086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Yellow fever (YF) is an endemic mosquito-borne disease in Brazil, though many locations have not observed cases in recent decades. Some locations with low disease burden may resemble locations with higher disease burden through environmental and ecohydrological characteristics, which are known to impact YF burden, motivating increased or continued prevention measures such as vaccination, mosquito control or surveillance. This study aimed to use environmental characteristics to estimate vulnerability to observing high YF burden among all Brazilian municipalities. Vulnerability was defined in three categories based on yearly incidence between 2000 and 2017: minimal, low and high vulnerability. A cumulative logit model was fit to these categories using environmental and ecohydrological predictors, selecting those that provided the most accurate model fit. Per cent of days with precipitation, mean temperature, biome, population density, elevation, vegetation and nearby disease occurrence were included in best-fitting models. Model results were applied to estimate vulnerability nationwide. Municipalities with highest probability of observing high vulnerability was found in the North and Central-West (2000-2016) as well as the Southeast (2017) regions. Results of this study serve to identify specific locations to prioritize new or ongoing surveillance and prevention of YF based on underlying ecohydrological conditions.
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Affiliation(s)
- Joseph L. Servadio
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN, USA
- Center for Infectious Disease Dynamics and Department of Biology, Pennsylvania State University, University Park, PA, USA
| | - Claudia Muñoz-Zanzi
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Matteo Convertino
- Future Ecosystems Lab, Tsinghua SIGS, Tsinghua University, Shenzhen, People's Republic of China
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Holmes CJ, Brown ES, Sharma D, Nguyen Q, Spangler AA, Pathak A, Payton B, Warden M, Shah AJ, Shaw S, Benoit JB. Bloodmeal regulation in mosquitoes curtails dehydration-induced mortality, altering vectorial capacity. JOURNAL OF INSECT PHYSIOLOGY 2022; 137:104363. [PMID: 35121007 PMCID: PMC8885900 DOI: 10.1016/j.jinsphys.2022.104363] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
Mosquitoes readily lose water when exposed to any humidity less than that of near saturated air unless mitigated, leading to shifts in behavior, survival, distribution, and reproduction. In this study, we conducted a series of physiological experiments on two prominent species in the Culicinae subfamily: Culex pipiens, a vector of West Nile virus, and Aedes aegypti, a vector of yellow fever and Zika to examine the effects of dehydration. We exposed C. pipiens and A. aegypti to non-dehydrating conditions (saturated air), dehydrating conditions (air at a 0.89 kPa saturation vapor pressure deficit), several recovery conditions, as well as to bloodfeeding opportunities. We show that dehydrated mosquitoes increase bloodfeeding propensity, improve retention, and decrease excretion of a post-dehydration bloodmeal. In addition, mosquitoes that take a bloodmeal prior to dehydration exposure show increased survival over non-bloodfed counterparts. Dehydration-induced alterations in survival, reproduction, and bloodfeeding propensity of C. pipiens and A. aegypti resulted in marked changes to vectorial capacity. Ultimately, these results become increasingly important as drought intensifies in association with climate change and mosquitoes become more likely to experience arid periods.
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Affiliation(s)
- Christopher J Holmes
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States.
| | - Elliott S Brown
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Dhriti Sharma
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Quynh Nguyen
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Austin A Spangler
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Atit Pathak
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Blaine Payton
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Matthew Warden
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Ashay J Shah
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Samantha Shaw
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
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10
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Sadeghieh T, Sargeant JM, Greer AL, Berke O, Dueymes G, Gachon P, Ogden NH, Ng V. Yellow fever virus outbreak in Brazil under current and future climate. Infect Dis Model 2021; 6:664-677. [PMID: 33997536 PMCID: PMC8090996 DOI: 10.1016/j.idm.2021.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/20/2021] [Accepted: 04/05/2021] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION Yellow fever (YF) is primarily transmitted by Haemagogus species of mosquitoes. Under climate change, mosquitoes and the pathogens that they carry are expected to develop faster, potentially impacting the case count and duration of YF outbreaks. The aim of this study was to determine how YF virus outbreaks in Brazil may change under future climate, using ensemble simulations from regional climate models under RCP4.5 and RCP8.5 scenarios for three time periods: 2011-2040 (short-term), 2041-2070 (mid-term), and 2071-2100 (long-term). METHODS A compartmental model was developed to fit the 2017/18 YF outbreak data in Brazil using least squares optimization. To explore the impact of climate change, temperature-sensitive mosquito parameters were set to change over projected time periods using polynomial equations fitted to their relationship with temperature according to the average temperature for years 2011-2040, 2041-2070, and 2071-2100 for climate change scenarios using RCP4.5 and RCP8.5, where RCP4.5/RCP8.5 corresponds to intermediate/high radiative forcing values and to moderate/higher warming trends. A sensitivity analysis was conducted to determine how the temperature-sensitive parameters impacted model results, and to determine how vaccination could play a role in reducing YF in Brazil. RESULTS Yellow fever case projections for Brazil from the models varied when climate change scenarios were applied, including the peak clinical case incidence, cumulative clinical case incidence, time to peak incidence, and the outbreak duration. Overall, a decrease in YF cases and outbreak duration was observed. Comparing the observed incidence in 2017/18 to the projected incidence in 2070-2100, for RCP4.5, the cumulative case incidence decreased from 184 to 161, and the outbreak duration decreased from 21 to 20 weeks. For RCP8.5, the peak case incidence decreased from 184 to 147, and the outbreak duration decreased from 21 to 17 weeks. The observed decrease was primarily due to temperature increasing beyond that suitable for Haemagogus mosquito survival. CONCLUSIONS Climate change is anticipated to have an impact on mosquito-borne diseases. We found outbreaks of YF may reduce in intensity as temperatures increase in Brazil; however, temperature is not the only factor involved with disease transmission. Other factors must be explored to determine the attributable impact of climate change on mosquito-borne diseases.
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Affiliation(s)
- Tara Sadeghieh
- Population Medicine, University of Guelph, Guelph, Ontario, Canada
- Centre for Public Health and Zoonoses, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Guelph, Ontario, St. Hyacinthe, Québec, Canada
| | - Jan M. Sargeant
- Population Medicine, University of Guelph, Guelph, Ontario, Canada
- Centre for Public Health and Zoonoses, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Amy L. Greer
- Population Medicine, University of Guelph, Guelph, Ontario, Canada
- Centre for Public Health and Zoonoses, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Olaf Berke
- Population Medicine, University of Guelph, Guelph, Ontario, Canada
- Centre for Public Health and Zoonoses, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Guillaume Dueymes
- ESCER (Étude et Simulation du Climat à l’Échelle Régionale) Centre, Université du Québec à Montréal, Québec, Canada
| | - Philippe Gachon
- ESCER (Étude et Simulation du Climat à l’Échelle Régionale) Centre, Université du Québec à Montréal, Québec, Canada
| | - Nicholas H. Ogden
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Guelph, Ontario, St. Hyacinthe, Québec, Canada
| | - Victoria Ng
- Public Health Risk Sciences Division, National Microbiology Laboratory, Public Health Agency of Canada, Guelph, Ontario, St. Hyacinthe, Québec, Canada
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11
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Cracknell Daniels B, Gaythorpe K, Imai N, Dorigatti I. Yellow fever in Asia-a risk analysis. J Travel Med 2021; 28:taab015. [PMID: 33506250 PMCID: PMC8045179 DOI: 10.1093/jtm/taab015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND There is concern about the risk of yellow fever (YF) establishment in Asia, owing to rising numbers of urban outbreaks in endemic countries and globalisation. Following an outbreak in Angola in 2016, YF cases were introduced into China. Prior to this, YF had never been recorded in Asia, despite climatic suitability and the presence of mosquitoes. An outbreak in Asia could result in widespread fatalities and huge economic impact. Therefore, quantifying the potential risk of YF outbreaks in Asia is a public health priority. METHODS Using international flight data and YF incidence estimates from 2016, we quantified the risk of YF introduction via air travel into Asia. In locations with evidence of a competent mosquito population, the potential for autochthonous YF transmission was estimated using a temperature-dependent model of the reproduction number and a branching process model assuming a negative binomial distribution. RESULTS In total, 25 cities across Asia were estimated to be at risk of receiving at least one YF viraemic traveller during 2016. At their average temperatures, we estimated the probability of autochthonous transmission to be <50% in all cities, which was primarily due to the limited number of estimated introductions that year. CONCLUSION Despite the rise in air travel, we found low support for travel patterns between YF endemic countries and Asia resulting in autochthonous transmission during 2016. This supports the historic absence of YF in Asia and suggests it could be due to a limited number of introductions in previous years. Future increases in travel volumes or YF incidence can increase the number of introductions and the risk of autochthonous transmission. Given the high proportion of asymptomatic or mild infections and the challenges of YF surveillance, our model can be used to estimate the introduction and outbreak risk and can provide useful information to surveillance systems.
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Affiliation(s)
- Bethan Cracknell Daniels
- MRC Centre for Global Infectious Disease Analysis; and the Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London
| | - Katy Gaythorpe
- MRC Centre for Global Infectious Disease Analysis; and the Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London
| | - Natsuko Imai
- MRC Centre for Global Infectious Disease Analysis; and the Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London
| | - Ilaria Dorigatti
- MRC Centre for Global Infectious Disease Analysis; and the Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London
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Uchenna Emeribe A, Nasir Abdullahi I, O R Ajagbe O, Egede Ugwu C, Oloche Onoja S, Dahiru Abubakar S, Modesta Umeozuru C, Sunday Animasaun O, Omoruyi Omosigho P, Mukhtar Danmusa U, Alhaji Baba Mallam M, Saidu Aminu M, Yahaya H, Oyewusi S. Incidence, drivers and global health implications of the 2019/2020 yellow fever sporadic outbreaks in Sub-Saharan Africa. Pathog Dis 2021; 79:6178868. [PMID: 33739369 DOI: 10.1093/femspd/ftab017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 03/17/2021] [Indexed: 11/13/2022] Open
Abstract
The 2019 and 2020 sporadic outbreaks of yellow fever (YF) in Sub-Saharan African countries had raised a lot of global health concerns. This article aims to narratively review the vector biology, YF vaccination program, environmental factors and climatic changes, and to understand how they could facilitate the reemergence of YF. This study comprehensively reviewed articles that focused on the interplay and complexity of YF virus (YFV) vector diversity/competence, YF vaccine immunodynamics and climatic change impacts on YFV transmission as they influence the 2019/2020 sporadic outbreaks in Sub-Saharan Africa (SSA). Based on available reports, vectorial migration, climatic changes and YF immunization level could be reasons for the re-mergence of YF at the community and national levels. Essentially, the drivers of YFV infection due to spillover are moderately constant. However, changes in land use and landscape have been shown to influence sylvan-to-urban spillover. Furthermore, increased precipitation and warmer temperatures due to climate change are likely to broaden the range of mosquitoes' habitat. The 2019/2020 YF outbreaks in SSA is basically a result of inadequate vaccination campaigns, YF surveillance and vector control. Consequently, and most importantly, adequate immunization coverage must be implemented and properly achieved under the responsibility of the public health stakeholders.
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Affiliation(s)
- Anthony Uchenna Emeribe
- Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, University of Calabar, PMB 1115, Calabar, Nigeria
| | - Idris Nasir Abdullahi
- Department of Medical Laboratory Science, Faculty of Allied Sciences, Ahmadu Bello University, PMB 05 along Samaru road, Zaria, Nigeria
| | - Odunayo O R Ajagbe
- Department of Medical Laboratory Science, Ebonyi State University, P.M.B. 053, Abakaliki, Nigeria
| | - Charles Egede Ugwu
- Solina Center for International Research and development, 8 Libreville Crescent, Ahmadu Bello Way Wuse II, Abuja 23409, Nigeria
| | - Solomon Oloche Onoja
- Nigeria Field Epidemiology and Laboratory Training Programme, African Field Epidemiology Programme, Plot 801, Ebitu Ukiwe Street, Jabi, Abuja, Nigeria
| | - Sharafudeen Dahiru Abubakar
- Department of Medical Laboratory Science, Faculty of Allied Sciences, Ahmadu Bello University, PMB 05 along Samaru road, Zaria, Nigeria
| | | | | | - Pius Omoruyi Omosigho
- Faculty of Pharmacy, Kaduna State University, Tafawa Balewa Way, PMB 2339, Kaduna, Nigeria
| | - Umar Mukhtar Danmusa
- Department of Medical Laboratory Science, University of Nigeria, PMB, 420001 Nsukka, Nigeria
| | - Mala Alhaji Baba Mallam
- Department of Nursing Science, Maryam Abacha American University of Niger, ADS Avenue, Roi Muhammed VI Du Maroc Maradi, Republique Du Niger
| | - Maijiddah Saidu Aminu
- Department of Nursing Science, Maryam Abacha American University of Niger, ADS Avenue, Roi Muhammed VI Du Maroc Maradi, Republique Du Niger
| | - Hadiza Yahaya
- Department of Nursing Science, Maryam Abacha American University of Niger, ADS Avenue, Roi Muhammed VI Du Maroc Maradi, Republique Du Niger
| | - Silifat Oyewusi
- Department of Nursing Science, Maryam Abacha American University of Niger, ADS Avenue, Roi Muhammed VI Du Maroc Maradi, Republique Du Niger
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Oviposition behavior of wild yellow fever vector mosquitoes (Diptera: Culicidae) in an Atlantic Forest fragment, Rio de Janeiro state, Brazil. Sci Rep 2021; 11:6081. [PMID: 33727688 PMCID: PMC7966363 DOI: 10.1038/s41598-021-85752-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/05/2021] [Indexed: 11/30/2022] Open
Abstract
Although there are many studies on the control of mosquito vectors of the yellow fever virus (YFV) in tropical forests, there are still few ecological studies regarding abiotic factors effect on these mosquitoes. Here we characterize these effects on oviposition behavior, abundance, and diversity of mosquito vectors of YFV. The study was conducted in Córrego da Luz Municipal Park, in Casimiro de Abreu, Rio de Janeiro state, Brazil, from July 2018 to December 2019. Ovitraps were placed at ground level and 3 m high. The data were tested for normality using the Shapiro–Wilk test, followed by an independent sample analysis, the Mann–Whitney test. The Shannon Diversity Index was used to evaluate the abundance of mosquitos' eggs collected at both ground level and 3 m high. We highlight the presence of Haemagogus janthinomys and Hg. leucocelaenus, primary YFV vectors in forest areas. The abundance of Hg. leucocelaenus (63%), Hg. janthinomys (75%), and Aedes terrens (58%) was higher at the height of 3 m, while Ae. albopictus (52%) was higher at ground level. Aedes albopictus was positively correlated with temperature. Culicidae monitoring is essential for assessing the YFV transmission cycle in Atlantic forest fragments.
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14
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Ndeffo-Mbah ML, Pandey A. Global Risk and Elimination of Yellow Fever Epidemics. J Infect Dis 2021; 221:2026-2034. [PMID: 31545372 DOI: 10.1093/infdis/jiz375] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 07/16/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Yellow fever (YF) is a vector-borne viral hemorrhagic disease endemic in Africa and Latin America. In 2016, the World Health Organization (WHO) developed the Eliminate YF Epidemics strategy aiming at eliminating YF epidemics by 2026. METHODS We developed a spatiotemporal model of YF, accounting for the impact of temperature, vector distribution, and socioeconomic factors on disease transmission. We validated our model against previous estimates of YF basic reproductive number (R0). We used the model to estimate global risk of YF outbreaks and vaccination efforts needed to achieve elimination of YF epidemics. RESULTS We showed that the global risk of YF outbreaks is highly heterogeneous. High-risk transmission areas (R0 > 6) are mainly found in West Africa and the Equatorial region of Latin America. We showed that vaccination coverage needed to eliminate YF epidemics in an endemic country varies substantially between districts. In many endemic countries, a 90% vaccination coverage is needed to achieve elimination. However, in some high-risk districts in Africa, a 95% coverage may be required. CONCLUSIONS Global elimination of YF epidemics requires higher population-level immunity than the 80% coverage recommended by the WHO. Optimal YF vaccination strategy should be tailored to the risk profile of each endemic country.
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Affiliation(s)
- Martial L Ndeffo-Mbah
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences.,Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M University, College Station
| | - Abhishek Pandey
- Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut
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15
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Role of PDZ-binding motif from West Nile virus NS5 protein on viral replication. Sci Rep 2021; 11:3266. [PMID: 33547379 PMCID: PMC7865074 DOI: 10.1038/s41598-021-82751-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 01/25/2021] [Indexed: 01/30/2023] Open
Abstract
West Nile virus (WNV) is a Flavivirus, which can cause febrile illness in humans that may progress to encephalitis. Like any other obligate intracellular pathogens, Flaviviruses hijack cellular protein functions as a strategy for sustaining their life cycle. Many cellular proteins display globular domain known as PDZ domain that interacts with PDZ-Binding Motifs (PBM) identified in many viral proteins. Thus, cellular PDZ-containing proteins are common targets during viral infection. The non-structural protein 5 (NS5) from WNV provides both RNA cap methyltransferase and RNA polymerase activities and is involved in viral replication but its interactions with host proteins remain poorly known. In this study, we demonstrate that the C-terminal PBM of WNV NS5 recognizes several human PDZ-containing proteins using both in vitro and in cellulo high-throughput methods. Furthermore, we constructed and assayed in cell culture WNV replicons where the PBM within NS5 was mutated. Our results demonstrate that the PBM of WNV NS5 is important in WNV replication. Moreover, we show that knockdown of the PDZ-containing proteins TJP1, PARD3, ARHGAP21 or SHANK2 results in the decrease of WNV replication in cells. Altogether, our data reveal that interactions between the PBM of NS5 and PDZ-containing proteins affect West Nile virus replication.
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16
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Ogunlade ST, Meehan MT, Adekunle AI, Rojas DP, Adegboye OA, McBryde ES. A Review: Aedes-Borne Arboviral Infections, Controls and Wolbachia-Based Strategies. Vaccines (Basel) 2021; 9:32. [PMID: 33435566 PMCID: PMC7827552 DOI: 10.3390/vaccines9010032] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/28/2020] [Accepted: 01/05/2021] [Indexed: 12/31/2022] Open
Abstract
Arthropod-borne viruses (Arboviruses) continue to generate significant health and economic burdens for people living in endemic regions. Of these viruses, some of the most important (e.g., dengue, Zika, chikungunya, and yellow fever virus), are transmitted mainly by Aedes mosquitoes. Over the years, viral infection control has targeted vector population reduction and inhibition of arboviral replication and transmission. This control includes the vector control methods which are classified into chemical, environmental, and biological methods. Some of these control methods may be largely experimental (both field and laboratory investigations) or widely practised. Perceptively, one of the biological methods of vector control, in particular, Wolbachia-based control, shows a promising control strategy for eradicating Aedes-borne arboviruses. This can either be through the artificial introduction of Wolbachia, a naturally present bacterium that impedes viral growth in mosquitoes into heterologous Aedes aegypti mosquito vectors (vectors that are not natural hosts of Wolbachia) thereby limiting arboviral transmission or via Aedes albopictus mosquitoes, which naturally harbour Wolbachia infection. These strategies are potentially undermined by the tendency of mosquitoes to lose Wolbachia infection in unfavourable weather conditions (e.g., high temperature) and the inhibitory competitive dynamics among co-circulating Wolbachia strains. The main objective of this review was to critically appraise published articles on vector control strategies and specifically highlight the use of Wolbachia-based control to suppress vector population growth or disrupt viral transmission. We retrieved studies on the control strategies for arboviral transmissions via arthropod vectors and discussed the use of Wolbachia control strategies for eradicating arboviral diseases to identify literature gaps that will be instrumental in developing models to estimate the impact of these control strategies and, in essence, the use of different Wolbachia strains and features.
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Affiliation(s)
- Samson T. Ogunlade
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD 4811, Australia; (M.T.M.); (A.I.A.); (O.A.A.); (E.S.M.)
- College of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia
| | - Michael T. Meehan
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD 4811, Australia; (M.T.M.); (A.I.A.); (O.A.A.); (E.S.M.)
| | - Adeshina I. Adekunle
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD 4811, Australia; (M.T.M.); (A.I.A.); (O.A.A.); (E.S.M.)
| | - Diana P. Rojas
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia;
| | - Oyelola A. Adegboye
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD 4811, Australia; (M.T.M.); (A.I.A.); (O.A.A.); (E.S.M.)
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia;
| | - Emma S. McBryde
- Australian Institute of Tropical Health and Medicine, James Cook University, Townsville, QLD 4811, Australia; (M.T.M.); (A.I.A.); (O.A.A.); (E.S.M.)
- College of Medicine and Dentistry, James Cook University, Townsville, QLD 4811, Australia
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Bailey AL, Kang LI, de Assis Barros D'Elia Zanella LGF, Silveira CGT, Ho YL, Foquet L, Bial G, McCune BT, Duarte-Neto AN, Thomas A, Raué HP, Byrnes K, Kallas EG, Slifka MK, Diamond MS. Consumptive coagulopathy of severe yellow fever occurs independently of hepatocellular tropism and massive hepatic injury. Proc Natl Acad Sci U S A 2020; 117:32648-32656. [PMID: 33268494 PMCID: PMC7768776 DOI: 10.1073/pnas.2014096117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Yellow fever (YF) is a mosquito-transmitted viral disease that causes tens of thousands of deaths each year despite the long-standing deployment of an effective vaccine. In its most severe form, YF manifests as a hemorrhagic fever that causes severe damage to visceral organs. Although coagulopathy is a defining feature of severe YF in humans, the mechanism by which it develops remains uncertain. Hepatocytes are a major target of yellow fever virus (YFV) infection, and the coagulopathy in severe YF has long been attributed to massive hepatocyte infection and destruction that results in a defect in clotting factor synthesis. However, when we analyzed blood from Brazilian patients with severe YF, we found high concentrations of plasma D-dimer, a fibrin split product, suggestive of a concurrent consumptive process. To define the relationship between coagulopathy and hepatocellular tropism, we compared infection and disease in Fah-/-, Rag2-/-, and Il2rɣ-/- mice engrafted with human hepatocytes (hFRG mice) and rhesus macaques using a highly pathogenic African YFV strain. YFV infection of macaques and hFRG mice caused substantial hepatocyte infection, liver damage, and coagulopathy as defined by virological, clinical, and pathological criteria. However, only macaques developed a consumptive coagulopathy whereas YFV-infected hFRG mice did not. Thus, infection of cell types other than hepatocytes likely contributes to the consumptive coagulopathy associated with severe YF in primates and humans. These findings expand our understanding of viral hemorrhagic disease and associated coagulopathy and suggest directions for clinical management of severe YF cases.
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Affiliation(s)
- Adam L Bailey
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110;
| | - Liang-I Kang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | | | - Cássia G T Silveira
- Division of Clinical Immunology and Allergy, School of Medicine, University of São Paulo, Sao Paulo, Brazil 01246 903
| | - Yeh-Li Ho
- Department of Infectious and Parasitic Diseases, School of Medicine, University of São Paulo, Sao Paulo, Brazil 01246 903
| | | | - Greg Bial
- Yecuris Corporation, Tualatin, OR 97062
| | - Broc T McCune
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
| | - Amaro Nunes Duarte-Neto
- Department of Pathology, Clinical Hospital, School of Medicine, University of São Paulo, Sao Paulo, Brazil 01246 903
| | - Archana Thomas
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006
| | - Hans-Peter Raué
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006
| | - Kathleen Byrnes
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Esper G Kallas
- Department of Infectious and Parasitic Diseases, School of Medicine, University of São Paulo, Sao Paulo, Brazil 01246 903
| | - Mark K Slifka
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006
| | - Michael S Diamond
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110;
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
- The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110
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Bothra A, Maheswari A, Singh M, Pawar M, Jodhani K. Cutaneous manifestations of viral outbreaks. Australas J Dermatol 2020; 62:27-36. [PMID: 32895964 DOI: 10.1111/ajd.13421] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/13/2022]
Abstract
As the world tries to grapple with the COVID-19 pandemic, dermatologists are left in a lurch as there is a lacuna in dermatologic literature as well as training regarding the cutaneous manifestations of varied viral agents capable of causing epidemics/pandemics or the potential to be bio-weaponised. Such outbreaks have the potential to become a pandemic given this age of globalisation. The quote by George Santayana stands true 'Those who cannot remember the past are condemned to repeat it'. Thus, this article lends a perspective to the recent viral outbreaks and is aimed at summarising these agents and their clinical features to serve as a quick reference for dermatologists.
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Affiliation(s)
- Atul Bothra
- Department of Dermatology, Gauhati Medical College & Hospital, Guwahati, India
| | - Anshu Maheswari
- Consultant Dermatologist, Private Practice, New Delhi, India
| | - Mehak Singh
- Department of Dermatology, JK Medical College & LN Hospital, Bhopal, India
| | - Manoj Pawar
- Department of Dermatology, MVP's Dr.V.P Medical College & Hospital & Research center, Nashik, India
| | - Kirti Jodhani
- Department of Dermatology, Gauhati Medical College & Hospital, Guwahati, India
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Guth S, Hanley KA, Althouse BM, Boots M. Ecological processes underlying the emergence of novel enzootic cycles: Arboviruses in the neotropics as a case study. PLoS Negl Trop Dis 2020; 14:e0008338. [PMID: 32790670 PMCID: PMC7425862 DOI: 10.1371/journal.pntd.0008338] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Pathogens originating from wildlife (zoonoses) pose a significant public health burden, comprising the majority of emerging infectious diseases. Efforts to control and prevent zoonotic disease have traditionally focused on animal-to-human transmission, or "spillover." However, in the modern era, increasing international mobility and commerce facilitate the spread of infected humans, nonhuman animals (hereafter animals), and their products worldwide, thereby increasing the risk that zoonoses will be introduced to new geographic areas. Imported zoonoses can potentially "spill back" to infect local wildlife-a danger magnified by urbanization and other anthropogenic pressures that increase contacts between human and wildlife populations. In this way, humans can function as vectors, dispersing zoonoses from their ancestral enzootic systems to establish reservoirs elsewhere in novel animal host populations. Once established, these enzootic cycles are largely unassailable by standard control measures and have the potential to feed human epidemics. Understanding when and why translocated zoonoses establish novel enzootic cycles requires disentangling ecologically complex and stochastic interactions between the zoonosis, the human population, and the natural ecosystem. In this Review, we address this challenge by delineating potential ecological mechanisms affecting each stage of enzootic establishment-wildlife exposure, enzootic infection, and persistence-applying existing ecological concepts from epidemiology, invasion biology, and population ecology. We ground our discussion in the neotropics, where four arthropod-borne viruses (arboviruses) of zoonotic origin-yellow fever, dengue, chikungunya, and Zika viruses-have separately been introduced into the human population. This paper is a step towards developing a framework for predicting and preventing novel enzootic cycles in the face of zoonotic translocations.
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Affiliation(s)
- Sarah Guth
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
| | - Kathryn A. Hanley
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Benjamin M. Althouse
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
- Epidemiology, Institute for Disease Modeling, Bellevue, Washington, United States of America
- Information School, University of Washington, Seattle, Washington, United States of America
| | - Mike Boots
- Department of Integrative Biology, University of California, Berkeley, California, United States of America
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20
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Gaythorpe KA, Hamlet A, Cibrelus L, Garske T, Ferguson NM. The effect of climate change on yellow fever disease burden in Africa. eLife 2020; 9:55619. [PMID: 32718436 PMCID: PMC7386919 DOI: 10.7554/elife.55619] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 07/01/2020] [Indexed: 12/27/2022] Open
Abstract
Yellow Fever (YF) is an arbovirus endemic in tropical regions of South America and Africa and it is estimated to cause 78,000 deaths a year in Africa alone. Climate change may have substantial effects on the transmission of YF and we present the first analysis of the potential impact on disease burden. We extend an existing model of YF transmission to account for rainfall and a temperature suitability index and project transmission intensity across the African endemic region in the context of four climate change scenarios. We use these transmission projections to assess the change in burden in 2050 and 2070. We find disease burden changes heterogeneously across the region. In the least severe scenario, we find a 93.0%[95%CI(92.7, 93.2%)] chance that annual deaths will increase in 2050. This change in epidemiology will complicate future control efforts. Thus, we may need to consider the effect of changing climatic variables on future intervention strategies.
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Affiliation(s)
| | | | | | - Tini Garske
- Imperial College London, London, United Kingdom
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21
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Couto-Lima D, Andreazzi CS, Leite PJ, Bersot MIL, Alencar J, Lourenço-de-Oliveira R. Seasonal population dynamics of the primary yellow fever vector Haemagogus leucocelaenus (Dyar & Shannon) (Diptera: Culicidae) is mainly influenced by temperature in the Atlantic Forest, southeast Brazil. Mem Inst Oswaldo Cruz 2020; 115:e200218. [PMID: 32696917 PMCID: PMC7370926 DOI: 10.1590/0074-02760200218] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/30/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Southeast Brazil has recently experienced a Yellow Fever virus (YFV) outbreak where the mosquito Haemagogus leucocelaenus was a primary vector. Climatic factors influence the abundance of mosquito vectors and arbovirus transmission. OBJECTIVES We aimed at describing the population dynamics of Hg. leucocelaenus in a county touched by the recent YFV outbreak. METHODS Fortnightly egg collections with ovitraps were performed from November 2012 to February 2017 in a forest in Nova Iguaçu, Rio de Janeiro, Brazil. The effects of mean temperature and rainfall on the Hg. leucocelaenus population dynamics were explored. FINDINGS Hg. leucocelaenus eggs were continuously collected throughout the study, with a peak in the warmer months (December-March). The climatic variables had a time-lagged effect and four weeks before sampling was the best predictor for the positivity of ovitraps and total number of eggs collected. The probability of finding > 50% positive ovitraps increased when the mean temperature was above 24ºC. The number of Hg. leucocelaenus eggs expressively increase when the mean temperature and accumulated precipitation surpassed 27ºC and 100 mm, respectively, although the effect of rainfall was less pronounced. MAIN CONCLUSIONS Monitoring population dynamics of Hg. leucocelaenus and climatic factors in YFV risk areas, especially mean temperature, may assist in developing climate-based surveillance procedures to timely strengthening prophylaxis and control.
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Affiliation(s)
- Dinair Couto-Lima
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Mosquitos Transmissores de Hematozoários, Rio de Janeiro, RJ, Brasil
| | - Cecilia S Andreazzi
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios, Rio de Janeiro, RJ, Brasil
| | | | - Maria Ignez Lima Bersot
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Mosquitos Transmissores de Hematozoários, Rio de Janeiro, RJ, Brasil
| | - Jeronimo Alencar
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Diptera, Rio de Janeiro, RJ, Brasil
| | - Ricardo Lourenço-de-Oliveira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Mosquitos Transmissores de Hematozoários, Rio de Janeiro, RJ, Brasil
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22
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Danbaba UA, Garba SM. Stability Analysis and Optimal Control for Yellow Fever Model with Vertical Transmission. INTERNATIONAL JOURNAL OF APPLIED AND COMPUTATIONAL MATHEMATICS 2020; 6:105. [PMID: 32835032 PMCID: PMC7336115 DOI: 10.1007/s40819-020-00860-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this study, a deterministic model for the transmission dynamics of yellow fever (YF) in a human-mosquito setting in the presence of control measures is constructed and rigorously analyzed. In addition to horizontal transmissions, vertical transmission within mosquito population is incorporated. Analysis of the mosquito-only component of the model shows that the reduced model has a mosquito-extinction equilibrium, which is globally-asymptotically stable whenever the basic offspring number ( N 0 ) is less than unity. The vaccinated and type reproduction numbers of the full-model are computed. Condition for global-asymptotic stability of the disease-free equilibrium of the model whenN 0 > 1 is presented. It is shown that, fractional dosing of YF vaccine does not meet YF vaccination requirements. Optimal control theory is applied to the model to characterize the controls parameters. Using Pontryagin's maximum principle and modified forward-backward sweep technique, the necessary conditions for existence of solutions to the optimal control problem is determined. Numerical simulations of the models to assess the effect of fractional vaccine dosing on the disease dynamics and global sensitivity analysis are presented.
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Affiliation(s)
- UA Danbaba
- Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria, 0002 South Africa
| | - SM Garba
- Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria, 0002 South Africa
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23
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Staples JE, Barrett ADT, Wilder-Smith A, Hombach J. Review of data and knowledge gaps regarding yellow fever vaccine-induced immunity and duration of protection. NPJ Vaccines 2020; 5:54. [PMID: 32655896 PMCID: PMC7338446 DOI: 10.1038/s41541-020-0205-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 05/29/2020] [Indexed: 12/13/2022] Open
Abstract
Yellow fever (YF) virus is a mosquito-borne flavivirus found in Sub-Saharan Africa and tropical South America. The virus causes YF, a viral hemorrhagic fever, which can be prevented by a live-attenuated vaccine, strain 17D. Despite the vaccine being very successful at decreasing disease risk, YF is considered a re-emerging disease due to the increased numbers of cases in the last 30 years. Until 2014, the vaccine was recommended to be administered with boosters every 10 years, but in 2014 the World Health Organization recommended removal of booster doses for all except special populations. This recommendation has been questioned and there have been reports of waning antibody titers in adults over time and more recently in pediatric populations. Clearly, the potential of waning antibody titers is a very important issue that needs to be carefully evaluated. In this Perspective, we review what is known about the correlate of protection for full-dose YF vaccine, current information on waning antibody titers, and gaps in knowledge. Overall, fundamental questions exist on the durability of protective immunity induced by YF vaccine, but interpretation of studies is complicated by the use of different assays and different cut-offs to measure seroprotective immunity, and differing results among certain endemic versus non-endemic populations. Notwithstanding the above, there are few well-characterized reports of vaccine failures, which one would expect to observe potentially more with the re-emergence of a severe disease. Overall, there is a need to improve YF disease surveillance, increase primary vaccination coverage rates in at-risk populations, and expand our understanding of the mechanism of protection of YF vaccine.
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Affiliation(s)
- J. Erin Staples
- Arboviral Diseases Branch, U.S. Centers for Disease Control and Prevention, Fort Collins, CO USA
| | - Alan D. T. Barrett
- Department of Pathology and Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX USA
| | - Annelies Wilder-Smith
- Institute of Public Health, University of Heidelberg, Heidelberg, Germany
- London School of Hygiene and Tropical Medicine, London, UK
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24
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Zhao S, Musa SS, Hebert JT, Cao P, Ran J, Meng J, He D, Qin J. Modelling the effective reproduction number of vector-borne diseases: the yellow fever outbreak in Luanda, Angola 2015-2016 as an example. PeerJ 2020; 8:e8601. [PMID: 32149023 PMCID: PMC7049463 DOI: 10.7717/peerj.8601] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/19/2020] [Indexed: 01/02/2023] Open
Abstract
The burden of vector-borne diseases (Dengue, Zika virus, yellow fever, etc.) gradually increased in the past decade across the globe. Mathematical modelling on infectious diseases helps to study the transmission dynamics of the pathogens. Theoretically, the diseases can be controlled and eventually eradicated by maintaining the effective reproduction number, (R eff ), strictly less than 1. We established a vector-host compartmental model, and derived (R eff ) for vector-borne diseases. The analytic form of the (R eff ) was found to be the product of the basic reproduction number and the geometric average of the susceptibilities of the host and vector populations. The (R eff ) formula was demonstrated to be consistent with the estimates of the 2015-2016 yellow fever outbreak in Luanda, and distinguished the second minor epidemic wave. For those using the compartmental model to study the vector-borne infectious disease epidemics, we further remark that it is important to be aware of whether one or two generations is considered for the transition "from host to vector to host" in reproduction number calculation.
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Affiliation(s)
- Shi Zhao
- School of Nursing, Hong Kong Polytechnic University, Hong Kong, China
- Division of Biostatistics, JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong, China
- Clinical Trials and Biostatistics Lab, Shenzhen Research Institute, Chinese University of Hong Kong, Shenzhen, China
| | - Salihu S. Musa
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Jay T. Hebert
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Peihua Cao
- Department of Hepatobiliary Surgery II, Zhujiang Hospital, Southern Medical University, Guangzhou, China
| | - Jinjun Ran
- School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Jiayi Meng
- School of Economics and Finance, Xi’an International Studies University, Xi’an, China
| | - Daihai He
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Jing Qin
- School of Nursing, Hong Kong Polytechnic University, Hong Kong, China
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25
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Chen LH, Wilson ME. Yellow fever control: current epidemiology and vaccination strategies. TROPICAL DISEASES TRAVEL MEDICINE AND VACCINES 2020; 6:1. [PMID: 31938550 PMCID: PMC6954598 DOI: 10.1186/s40794-020-0101-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/05/2020] [Indexed: 12/16/2022]
Abstract
Yellow fever (YF) outbreaks continue, have expanded into new areas and threaten large populations in South America and Africa. Predicting where epidemics might occur must take into account local mosquito populations and specific YF virus strain, as well as ecoclimatic conditions, sociopolitical and demographic factors including population size, density, and mobility, and vaccine coverage. Populations of Aedes aegypti and Aedes albopictus from different regions vary in susceptibility to and capacity to transmit YF virus. YF virus cannot be eliminated today because the virus circulates in animal reservoirs, but human disease could be eliminated with wide use of the vaccine. WHO EYE (Eliminate Yellow Fever Epidemics) is a welcome plan to control YF, with strategies to be carried out from 2017 to 2026: to expand use of YF vaccine, to prevent international spread, and to contain outbreaks rapidly. YF vaccination is the mainstay in controlling YF outbreaks, but global supply is insufficient. Therefore, dose-sparing strategies have been proposed including fractional dosing and intradermal administration. Fractional dosing has been effectively used in outbreak control but currently does not satisfy International Health Regulations; special documentation is needed for international travel. Vector control is another facet in preventing YF outbreaks, and novel methods are being considered and proposed.
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Affiliation(s)
- Lin H Chen
- 1Mount Auburn Hospital, 330 Mount Auburn Street, Cambridge, MA 02138 USA.,2Harvard Medical School, Boston, MA USA
| | - Mary E Wilson
- 3Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, MA USA.,4Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, USA
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26
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Tosta SFDO, Passos MS, Kato R, Salgado Á, Xavier J, Jaiswal AK, Soares SC, Azevedo V, Giovanetti M, Tiwari S, Alcantara LCJ. Multi-epitope based vaccine against yellow fever virus applying immunoinformatics approaches. J Biomol Struct Dyn 2020; 39:219-235. [PMID: 31854239 DOI: 10.1080/07391102.2019.1707120] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Yellow fever disease is considered a re-emerging major health issue which has caused recent outbreaks with a high number of deaths. Tropical countries, mainly African and South American, are the most affected by Yellow fever outbreaks. Despite the availability of an attenuated vaccine, its use is limited for some groups such as pregnant and nursing women, immunocompromised and immunosuppressed patients, elderly people >65 years, infants <6 months and patients with biological disorders like thymus disorders. In order to achieve new preventive measures, we applied immunoinformatics approaches to develop a multi-epitope-based subunit vaccine for Yellow fever virus. Different epitopes, related to humoral and cell-mediated immunity, were predicted for complete polyproteins of two Yellow fever strains (Asibi and 17 D vaccine). Those epitopes common for both strains were mapped into a set of 137 sequences of Yellow fever virus, including 77 sequences from a recent outbreak at the state of Minas Gerais, southeast Brazil. Therefore, the present work uses robust bioinformatics approaches for the identification of a multi-epitope vaccine against the Yellow fever virus. Our results indicate that the identified multi-epitope vaccine might stimulate humoral and cellular immune responses and could be a potential vaccine candidate against Yellow fever virus infection. Hence, it should be subjected to further experimental validations. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Stephane Fraga de Oliveira Tosta
- Postgraduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Mariana Santana Passos
- Department of Genetics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Rodrigo Kato
- Postgraduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Álvaro Salgado
- Postgraduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Joilson Xavier
- Department of Genetics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Arun Kumar Jaiswal
- Postgraduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.,Department of Immunology, Microbiology and Parasitology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Siomar C Soares
- Department of Immunology, Microbiology and Parasitology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Vasco Azevedo
- Postgraduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Marta Giovanetti
- Department of Genetics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.,Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Manguinhos, Rio De Janeiro, Brazil
| | - Sandeep Tiwari
- Postgraduate Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Luiz Carlos Junior Alcantara
- Department of Genetics, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.,Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Manguinhos, Rio De Janeiro, Brazil
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27
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Onyango MG, Bialosuknia SM, Payne AF, Mathias N, Kuo L, Vigneron A, DeGennaro M, Ciota AT, Kramer LD. Increased temperatures reduce the vectorial capacity of Aedes mosquitoes for Zika virus. Emerg Microbes Infect 2020; 9:67-77. [PMID: 31894724 PMCID: PMC6968261 DOI: 10.1080/22221751.2019.1707125] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rapid and significant range expansion of both Zika virus (ZIKV) and its Aedes vector species has resulted in ZIKV being declared a global health threat. Mean temperatures are projected to increase globally, likely resulting in alterations of the transmission potential of mosquito-borne pathogens. To understand the effect of diurnal temperature range on the vectorial capacity of Ae. aegypti and Ae. albopictus for ZIKV, longevity, blood-feeding and vector competence were assessed at two temperature regimes following feeding on infectious blood meals. Higher temperatures resulted in decreased longevity of Ae. aegypti [Log-rank test, χ2, df 35.66, 5, P < 0.001] and a decrease in blood-feeding rates of Ae. albopictus [Fisher's exact test, P < 0.001]. Temperature had a population and species-specific impact on ZIKV infection rates. Overall, Ae. albopictus reared at the lowest temperature regime demonstrated the highest vectorial capacity (0.53) and the highest transmission efficiency (57%). Increased temperature decreased vectorial capacity across groups yet more significant effects were measured with Ae. aegypti relative to Ae. albopictus. The results of this study suggest that future increases in temperature in the Americas could significantly impact vector competence, blood-feeding and longevity, and potentially decrease the overall vectorial capacity of Aedes mosquitoes in the Americas.
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Affiliation(s)
| | - Sean M Bialosuknia
- Griffin Laboratory, New York State Department of Health, Slingerlands, NY, USA.,School of Public Health, State University of New York Albany, Albany, NY, USA
| | - Anne F Payne
- Griffin Laboratory, New York State Department of Health, Slingerlands, NY, USA
| | - Nicholas Mathias
- Griffin Laboratory, New York State Department of Health, Slingerlands, NY, USA
| | - Lili Kuo
- Griffin Laboratory, New York State Department of Health, Slingerlands, NY, USA
| | - Aurélien Vigneron
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Matthew DeGennaro
- Department of Biological Sciences, Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Alexander T Ciota
- Griffin Laboratory, New York State Department of Health, Slingerlands, NY, USA.,School of Public Health, State University of New York Albany, Albany, NY, USA
| | - Laura D Kramer
- Griffin Laboratory, New York State Department of Health, Slingerlands, NY, USA.,School of Public Health, State University of New York Albany, Albany, NY, USA
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28
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Risk of yellow fever virus importation into the United States from Brazil, outbreak years 2016-2017 and 2017-2018. Sci Rep 2019; 9:20420. [PMID: 31892703 PMCID: PMC6938482 DOI: 10.1038/s41598-019-56521-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 12/12/2019] [Indexed: 11/18/2022] Open
Abstract
Southeast Brazil has experienced two large yellow fever (YF) outbreaks since 2016. While the 2016–2017 outbreak mainly affected the states of Espírito Santo and Minas Gerais, the 2017–2018 YF outbreak primarily involved the states of Minas Gerais, São Paulo, and Rio de Janeiro, the latter two of which are highly populated and popular destinations for international travelers. This analysis quantifies the risk of YF virus (YFV) infected travelers arriving in the United States via air travel from Brazil, including both incoming Brazilian travelers and returning US travelers. We assumed that US travelers were subject to the same daily risk of YF infection as Brazilian residents. During both YF outbreaks in Southeast Brazil, three international airports—Miami, New York-John F. Kennedy, and Orlando—had the highest risk of receiving a traveler infected with YFV. Most of the risk was observed among incoming Brazilian travelers. Overall, we found low risk of YFV introduction into the United States during the 2016–2017 and 2017–2018 outbreaks. Decision makers can use these results to employ the most efficient and least restrictive actions and interventions.
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29
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Kamiya T, Greischar MA, Wadhawan K, Gilbert B, Paaijmans K, Mideo N. Temperature-dependent variation in the extrinsic incubation period elevates the risk of vector-borne disease emergence. Epidemics 2019; 30:100382. [PMID: 32004794 DOI: 10.1016/j.epidem.2019.100382] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 11/29/2019] [Accepted: 12/01/2019] [Indexed: 12/24/2022] Open
Abstract
Identifying ecological drivers of disease transmission is central to understanding disease risks. For vector-borne diseases, temperature is a major determinant of transmission because vital parameters determining the fitness of parasites and vectors are highly temperature-sensitive, including the extrinsic incubation period required for parasites to develop within the vector. Temperature also underlies dramatic differences in the individual-level variation in the extrinsic incubation period, yet the influence of this variation in disease transmission is largely unexplored. We incorporate empirical estimates of dengue virus extrinsic incubation period and its variation across a range of temperatures into a stochastic model to examine the consequences for disease emergence. We find that such variation impacts the probability of disease emergence because exceptionally rapid, but empirically observed incubation - typically ignored by modelling only the average - increases the chance of disease emergence even at the limits of the temperature range for dengue transmission. We show that variation in the extrinsic incubation period causes the greatest proportional increase in the risk of disease emergence at cooler temperatures where the mean incubation period is long, and associated variation is large. Thus, ignoring EIP variation will likely lead to underestimation of the risk of vector-borne disease emergence in temperate climates.
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Affiliation(s)
- Tsukushi Kamiya
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada.
| | - Megan A Greischar
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Kiran Wadhawan
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Benjamin Gilbert
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Krijn Paaijmans
- Center for Evolution & Medicine, Biodesign Center for Immunotherapy, Vaccines and Virotherapy, School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Nicole Mideo
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
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30
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Disease Resurgence, Production Capability Issues and Safety Concerns in the Context of an Aging Population: Is There a Need for a New Yellow Fever Vaccine? Vaccines (Basel) 2019; 7:vaccines7040179. [PMID: 31717289 PMCID: PMC6963298 DOI: 10.3390/vaccines7040179] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 10/28/2019] [Accepted: 11/05/2019] [Indexed: 12/19/2022] Open
Abstract
Yellow fever is a potentially fatal, mosquito-borne viral disease that appears to be experiencing a resurgence in endemic areas in Africa and South America and spreading to non-endemic areas despite an effective vaccine. This trend has increased the level of concern about the disease and the potential for importation to areas in Asia with ecological conditions that can sustain yellow fever virus transmission. In this article, we provide a broad overview of yellow fever burden of disease, natural history, treatment, vaccine, prevention and control initiatives, and vaccine and therapeutic agent development efforts.
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31
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Childs ML, Nova N, Colvin J, Mordecai EA. Mosquito and primate ecology predict human risk of yellow fever virus spillover in Brazil. Philos Trans R Soc Lond B Biol Sci 2019; 374:20180335. [PMID: 31401964 PMCID: PMC6711306 DOI: 10.1098/rstb.2018.0335] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2019] [Indexed: 01/25/2023] Open
Abstract
Many (re)emerging infectious diseases in humans arise from pathogen spillover from wildlife or livestock, and accurately predicting pathogen spillover is an important public health goal. In the Americas, yellow fever in humans primarily occurs following spillover from non-human primates via mosquitoes. Predicting yellow fever spillover can improve public health responses through vector control and mass vaccination. Here, we develop and test a mechanistic model of pathogen spillover to predict human risk for yellow fever in Brazil. This environmental risk model, based on the ecology of mosquito vectors and non-human primate hosts, distinguished municipality-months with yellow fever spillover from 2001 to 2016 with high accuracy (AUC = 0.72). Incorporating hypothesized cyclical dynamics of infected primates improved accuracy (AUC = 0.79). Using boosted regression trees to identify gaps in the mechanistic model, we found that important predictors include current and one-month lagged environmental risk, vaccine coverage, population density, temperature and precipitation. More broadly, we show that for a widespread human viral pathogen, the ecological interactions between environment, vectors, reservoir hosts and humans can predict spillover with surprising accuracy, suggesting the potential to improve preventive action to reduce yellow fever spillover and avert onward epidemics in humans. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
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Affiliation(s)
- Marissa L. Childs
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA 94305, USA
| | - Nicole Nova
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Justine Colvin
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Erin A. Mordecai
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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32
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Fourié T, Grard G, Leparc-Goffart I, Briolant S, Fontaine A. Variability of Zika Virus Incubation Period in Humans. Open Forum Infect Dis 2018; 5:ofy261. [PMID: 30397624 PMCID: PMC6207619 DOI: 10.1093/ofid/ofy261] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/09/2018] [Indexed: 11/14/2022] Open
Abstract
Zika virus (ZIKV) has recently emerged in numerous tropical countries worldwide. In this study, we estimated ZIKV incubation period distribution using time-to-event models adapted to interval-censored data based on declared date of travels from 123 symptomatic travelers returning from areas with active ZIKV transmission. The median time and 95th percentile of ZIKV incubation period was estimated to 6.8 days (95% confidence interval [CI], 5.8–7.7 days) and 15.4 days (95% CI, 12.7–19.7 days), respectively. Determining the incubation period for ZIKV is beneficial to improve protection guidelines.
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Affiliation(s)
- Toscane Fourié
- Institut de Recherche Biomédicale des Armées, Centre National de Référence des Arbovirus, Marseille, France.,Unité Mixte de Recherche (UMR) Unité des Virus Emergents, Aix-Marseille Université, Institut de recherche pour le développement (IRD) 190, INSERM 1207, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Marseille, France
| | - Gilda Grard
- Institut de Recherche Biomédicale des Armées, Centre National de Référence des Arbovirus, Marseille, France.,Unité Mixte de Recherche (UMR) Unité des Virus Emergents, Aix-Marseille Université, Institut de recherche pour le développement (IRD) 190, INSERM 1207, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Marseille, France
| | - Isabelle Leparc-Goffart
- Institut de Recherche Biomédicale des Armées, Centre National de Référence des Arbovirus, Marseille, France.,Unité Mixte de Recherche (UMR) Unité des Virus Emergents, Aix-Marseille Université, Institut de recherche pour le développement (IRD) 190, INSERM 1207, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Marseille, France
| | - Sébastien Briolant
- Unité de Parasitologie et Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France.,Aix Marseille Université, IRD, Assistance Publique-Hôpitaux de Marseille (AP-HM), Service de santé des armées (SSA), UMR Vecteurs - Infections Tropicales et Méditerranéennes (VITROME), IHU, Méditerranée Infection, France
| | - Albin Fontaine
- Unité de Parasitologie et Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Marseille, France.,Aix Marseille Université, IRD, Assistance Publique-Hôpitaux de Marseille (AP-HM), Service de santé des armées (SSA), UMR Vecteurs - Infections Tropicales et Méditerranéennes (VITROME), IHU, Méditerranée Infection, France
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33
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Waggoner JJ, Rojas A, Pinsky BA. Yellow Fever Virus: Diagnostics for a Persistent Arboviral Threat. J Clin Microbiol 2018; 56:e00827-18. [PMID: 30021822 PMCID: PMC6156298 DOI: 10.1128/jcm.00827-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Yellow fever (YF) is the prototypical hemorrhagic fever and results from infection with yellow fever virus (YFV), which is endemic to regions of Africa and South America. Despite the availability of an effective vaccine, YFV continues to cause disease throughout regions where it is endemic, including intermittent large outbreaks among undervaccinated populations. A number of diagnostic methods and assays have been described for the detection of YFV infection, including viral culture, molecular testing, serology, and antigen detection. Commercial diagnostics are not widely available, and testing is generally performed at a small number of reference laboratories. The goal of this article, therefore, is to review available clinical diagnostics for YFV, which may not be familiar to many practitioners outside areas where it is endemic. Additionally, we identify gaps in our current knowledge about YF that pertain to diagnosis and describe interventions that may improve YFV detection.
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Affiliation(s)
- Jesse J Waggoner
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Global Health, Rollins School of Public Health, Atlanta, Georgia, USA
| | - Alejandra Rojas
- Departamento de Producción, Instituto de Investigaciones en Ciencias de la Salud, Universidad Nacional de Asunción, Asunción, Paraguay
| | - Benjamin A Pinsky
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
- Department of Medicine, Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, USA
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34
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Sanna A, Andrieu A, Carvalho L, Mayence C, Tabard P, Hachouf M, Cazaux CM, Enfissi A, Rousset D, Kallel H. Yellow fever cases in French Guiana, evidence of an active circulation in the Guiana Shield, 2017 and 2018. Euro Surveill 2018; 23:1800471. [PMID: 30205871 PMCID: PMC6134805 DOI: 10.2807/1560-7917.es.2018.23.36.1800471] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 09/06/2018] [Indexed: 12/02/2022] Open
Abstract
French Guiana (FG) is a French overseas region bordering Brazil and Suriname that is considered endemic for yellow fever (YF); vaccination is compulsory for residents and travellers. In August 2017 and 2018, two sporadic YF cases were notified 1 year apart, confirming that sylvatic YF virus circulation is active in the region. YF vaccination coverage should be closely monitored and improved in FG and neighbouring territories and clinicians should be aware of the risk.
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Affiliation(s)
- Alice Sanna
- Public health direction, Regional Health Agency (Agence régionale de santé Guyane), Cayenne, French Guiana
| | - Audrey Andrieu
- Regional Unit of Santé publique France (France's national public health agency), Cayenne, French Guiana
| | - Luisiane Carvalho
- Regional Unit of Santé publique France (France's national public health agency), Cayenne, French Guiana
| | | | - Philippe Tabard
- Public health direction, Regional Health Agency (Agence régionale de santé Guyane), Cayenne, French Guiana
| | - Marina Hachouf
- APHP-HUPNVS, Department of Anesthesiology and Critical Care, Beaujon Hospital, Clichy, France
| | - Claire-Marie Cazaux
- Public health direction, Regional Health Agency (Agence régionale de santé Guyane), Cayenne, French Guiana
| | - Antoine Enfissi
- National Reference Laboratory for Arboviruses, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Dominique Rousset
- National Reference Laboratory for Arboviruses, Institut Pasteur de la Guyane, Cayenne, French Guiana
| | - Hatem Kallel
- Intensive Care Unit, Cayenne Hospital, French Guiana
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35
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Moraga P, Dorigatti I, Kamvar ZN, Piatkowski P, Toikkanen SE, Nagraj VP, Donnelly CA, Jombart T. epiflows: an R package for risk assessment of travel-related spread of disease. F1000Res 2018; 7:1374. [PMID: 31543947 PMCID: PMC6738191 DOI: 10.12688/f1000research.16032.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/22/2018] [Indexed: 11/20/2022] Open
Abstract
As international travel increases worldwide, new surveillance tools are needed to help identify locations where diseases are most likely to be spread and prevention measures need to be implemented. In this paper we present epiflows, an R package for risk assessment of travel-related spread of disease. epiflows produces estimates of the expected number of symptomatic and/or asymptomatic infections that could be introduced to other locations from the source of infection. Estimates (average and confidence intervals) of the number of infections introduced elsewhere are obtained by integrating data on the cumulative number of cases reported, population movement, length of stay and information on the distributions of the incubation and infectious periods of the disease. The package also provides tools for geocoding and visualization. We illustrate the use of epiflows by assessing the risk of travel-related spread of yellow fever cases in Southeast Brazil in December 2016 to May 2017.
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Affiliation(s)
- Paula Moraga
- Department of Mathematical Sciences, University of Bath, Bath, BA2 7AY, UK
| | - Ilaria Dorigatti
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
| | - Zhian N. Kamvar
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
| | - Pawel Piatkowski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | | | - VP Nagraj
- School of Medicine, Research Computing, University of Virginia, Virginia, USA
| | - Christl A. Donnelly
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
- Department of Statistics, University of Oxford, Oxford, OX1 3LB, UK
| | - Thibaut Jombart
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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36
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Moraga P, Dorigatti I, Kamvar ZN, Piatkowski P, Toikkanen SE, Nagraj VP, Donnelly CA, Jombart T. epiflows: an R package for risk assessment of travel-related spread of disease. F1000Res 2018; 7:1374. [PMID: 31543947 PMCID: PMC6738191 DOI: 10.12688/f1000research.16032.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/26/2019] [Indexed: 10/15/2023] Open
Abstract
As international travel increases worldwide, new surveillance tools are needed to help identify locations where diseases are most likely to be spread and prevention measures need to be implemented. In this paper we present epiflows, an R package for risk assessment of travel-related spread of disease. epiflows produces estimates of the expected number of symptomatic and/or asymptomatic infections that could be introduced to other locations from the source of infection. Estimates (average and confidence intervals) of the number of infections introduced elsewhere are obtained by integrating data on the cumulative number of cases reported, population movement, length of stay and information on the distributions of the incubation and infectious periods of the disease. The package also provides tools for geocoding and visualization. We illustrate the use of epiflows by assessing the risk of travel-related spread of yellow fever cases in Southeast Brazil in December 2016 to May 2017.
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Affiliation(s)
- Paula Moraga
- Department of Mathematical Sciences, University of Bath, Bath, BA2 7AY, UK
| | - Ilaria Dorigatti
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
| | - Zhian N. Kamvar
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
| | - Pawel Piatkowski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | | | - VP Nagraj
- School of Medicine, Research Computing, University of Virginia, Virginia, USA
| | - Christl A. Donnelly
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
- Department of Statistics, University of Oxford, Oxford, OX1 3LB, UK
| | - Thibaut Jombart
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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37
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Moraga P, Dorigatti I, Kamvar ZN, Piatkowski P, Toikkanen SE, Nagraj VP, Donnelly CA, Jombart T. epiflows: an R package for risk assessment of travel-related spread of disease. F1000Res 2018; 7:1374. [PMID: 31543947 PMCID: PMC6738191 DOI: 10.12688/f1000research.16032.3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/10/2019] [Indexed: 11/28/2022] Open
Abstract
As international travel increases worldwide, new surveillance tools are needed to help identify locations where diseases are most likely to be spread and prevention measures need to be implemented. In this paper we present epiflows, an R package for risk assessment of travel-related spread of disease. epiflows produces estimates of the expected number of symptomatic and/or asymptomatic infections that could be introduced to other locations from the source of infection. Estimates (average and confidence intervals) of the number of infections introduced elsewhere are obtained by integrating data on the cumulative number of cases reported, population movement, length of stay and information on the distributions of the incubation and infectious periods of the disease. The package also provides tools for geocoding and visualization. We illustrate the use of epiflows by assessing the risk of travel-related spread of yellow fever cases in Southeast Brazil in December 2016 to May 2017.
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Affiliation(s)
- Paula Moraga
- Department of Mathematical Sciences, University of Bath, Bath, BA2 7AY, UK
| | - Ilaria Dorigatti
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
| | - Zhian N. Kamvar
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
| | - Pawel Piatkowski
- International Institute of Molecular and Cell Biology, Warsaw, Poland
| | | | - VP Nagraj
- School of Medicine, Research Computing, University of Virginia, Virginia, USA
| | - Christl A. Donnelly
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
- Department of Statistics, University of Oxford, Oxford, OX1 3LB, UK
| | - Thibaut Jombart
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College, London, W2 1PG, UK
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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38
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Towards the risk of yellow fever transmission in Europe. Clin Microbiol Infect 2018; 25:10-12. [PMID: 30170135 DOI: 10.1016/j.cmi.2018.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/18/2018] [Accepted: 08/19/2018] [Indexed: 11/22/2022]
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39
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Tesla B, Demakovsky LR, Mordecai EA, Ryan SJ, Bonds MH, Ngonghala CN, Brindley MA, Murdock CC. Temperature drives Zika virus transmission: evidence from empirical and mathematical models. Proc Biol Sci 2018; 285:20180795. [PMID: 30111605 PMCID: PMC6111177 DOI: 10.1098/rspb.2018.0795] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 07/23/2018] [Indexed: 12/17/2022] Open
Abstract
Temperature is a strong driver of vector-borne disease transmission. Yet, for emerging arboviruses we lack fundamental knowledge on the relationship between transmission and temperature. Current models rely on the untested assumption that Zika virus responds similarly to dengue virus, potentially limiting our ability to accurately predict the spread of Zika. We conducted experiments to estimate the thermal performance of Zika virus (ZIKV) in field-derived Aedes aegypti across eight constant temperatures. We observed strong, unimodal effects of temperature on vector competence, extrinsic incubation period and mosquito survival. We used thermal responses of these traits to update an existing temperature-dependent model to infer temperature effects on ZIKV transmission. ZIKV transmission was optimized at 29°C, and had a thermal range of 22.7°C-34.7°C. Thus, as temperatures move towards the predicted thermal optimum (29°C) owing to climate change, urbanization or seasonality, Zika could expand north and into longer seasons. By contrast, areas that are near the thermal optimum were predicted to experience a decrease in overall environmental suitability. We also demonstrate that the predicted thermal minimum for Zika transmission is 5°C warmer than that of dengue, and current global estimates on the environmental suitability for Zika are greatly over-predicting its possible range.
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Affiliation(s)
- Blanka Tesla
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - Leah R Demakovsky
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
| | | | - Sadie J Ryan
- Quantitative Disease Ecology and Conservation Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- College of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Matthew H Bonds
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, USA
| | | | - Melinda A Brindley
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Department of Population Health, University of Georgia, Athens, GA, USA
- Center for Vaccines and Immunology, University of Georgia, Athens, GA, USA
| | - Courtney C Murdock
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
- Center for Vaccines and Immunology, University of Georgia, Athens, GA, USA
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center of Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA
- River Basin Center, University of Georgia, Athens, GA, USA
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40
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Hamlet A, Jean K, Perea W, Yactayo S, Biey J, Van Kerkhove M, Ferguson N, Garske T. The seasonal influence of climate and environment on yellow fever transmission across Africa. PLoS Negl Trop Dis 2018; 12:e0006284. [PMID: 29543798 PMCID: PMC5854243 DOI: 10.1371/journal.pntd.0006284] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/30/2018] [Indexed: 11/19/2022] Open
Abstract
Background Yellow fever virus (YFV) is a vector-borne flavivirus endemic to Africa and Latin America. Ninety per cent of the global burden occurs in Africa where it is primarily transmitted by Aedes spp, with Aedes aegypti the main vector for urban yellow fever (YF). Mosquito life cycle and viral replication in the mosquito are heavily dependent on climate, particularly temperature and rainfall. We aimed to assess whether seasonal variations in climatic factors are associated with the seasonality of YF reports. Methodology/Principal findings We constructed a temperature suitability index for YFV transmission, capturing the temperature dependence of mosquito behaviour and viral replication within the mosquito. We then fitted a series of multilevel logistic regression models to a dataset of YF reports across Africa, considering location and seasonality of occurrence for seasonal models, against the temperature suitability index, rainfall and the Enhanced Vegetation Index (EVI) as covariates alongside further demographic indicators. Model fit was assessed by the Area Under the Curve (AUC), and models were ranked by Akaike’s Information Criterion which was used to weight model outputs to create combined model predictions. The seasonal model accurately captured both the geographic and temporal heterogeneities in YF transmission (AUC = 0.81), and did not perform significantly worse than the annual model which only captured the geographic distribution. The interaction between temperature suitability and rainfall accounted for much of the occurrence of YF, which offers a statistical explanation for the spatio-temporal variability in transmission. Conclusions/Significance The description of seasonality offers an explanation for heterogeneities in the West-East YF burden across Africa. Annual climatic variables may indicate a transmission suitability not always reflected in seasonal interactions. This finding, in conjunction with forecasted data, could highlight areas of increased transmission and provide insights into the occurrence of large outbreaks, such as those seen in Angola, the Democratic Republic of the Congo and Brazil. In this article, we describe the development of a model to quantify the seasonal dynamics of yellow fever virus (YFV) transmission across Africa. YFV is a flavivirus transmitted, within Africa, primarily by Aedes spp where it causes an estimated 78,000 deaths a year despite the presence of a safe and effective vaccine. The importance of sufficient vaccination, made difficult by a global shortage, has been highlighted by recent large scale, devastating, outbreaks in Angola, the Democratic Republic of the Congo and Brazil. Here we describe a novel way of parameterising the effect of temperature on YFV transmission and implement statistical models to predict both the geographic and temporal heterogeneities in transmissions, while demonstrating their robustness in comparison to models simply predicting geographic distribution. We believe this quantification of seasonality could lead to more precise applications of vaccination campaigns and vector-control programmes. In turn this would help maximise their impact, especially vital with limited resources, and could contribute to lessening the risk of large scale outbreaks. Not only this, but the methods described here could be applied to other Aedes-borne diseases and as such provide a useful tool in understanding, and combatting, several other important diseases such as dengue and zika.
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Affiliation(s)
- Arran Hamlet
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- * E-mail:
| | - Kévin Jean
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- Laboratoire MESuRS, Conservatoire National des Arts et Métiers, Paris, France
| | - William Perea
- WHO, Infectious Hazard Management, Geneva, Switzerland
| | | | - Joseph Biey
- WHO-AFRO, IST/WA, Ouagadougou, Burkina, Faso
| | - Maria Van Kerkhove
- WHO, Infectious Hazard Management, Geneva, Switzerland
- Centre for Global Health, Institut Pasteur, Paris, France
| | - Neil Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Tini Garske
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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41
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Dorigatti I, Hamlet A, Aguas R, Cattarino L, Cori A, Donnelly CA, Garske T, Imai N, Ferguson NM. International risk of yellow fever spread from the ongoing outbreak in Brazil, December 2016 to May 2017. ACTA ACUST UNITED AC 2018; 22:30572. [PMID: 28749337 PMCID: PMC5545764 DOI: 10.2807/1560-7917.es.2017.22.28.30572] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 07/11/2017] [Indexed: 11/20/2022]
Abstract
States in south-eastern Brazil were recently affected by the largest Yellow Fever (YF)
outbreak seen in a decade in Latin America. Here we provide a quantitative assessment of
the risk of travel-related international spread of YF indicating that the United States,
Argentina, Uruguay, Spain, Italy and Germany may have received at least one travel-related
YF case capable of seeding local transmission. Mitigating the risk of imported YF cases
seeding local transmission requires heightened surveillance globally.
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Affiliation(s)
- Ilaria Dorigatti
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Arran Hamlet
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Ricardo Aguas
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Lorenzo Cattarino
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Anne Cori
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Christl A Donnelly
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Tini Garske
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Natsuko Imai
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Neil M Ferguson
- MRC Centre for Outbreak analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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42
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Zhao S, Stone L, Gao D, He D. Modelling the large-scale yellow fever outbreak in Luanda, Angola, and the impact of vaccination. PLoS Negl Trop Dis 2018; 12:e0006158. [PMID: 29338001 PMCID: PMC5798855 DOI: 10.1371/journal.pntd.0006158] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 02/05/2018] [Accepted: 12/11/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Yellow fever (YF), transmitted via bites of infected mosquitoes, is a life-threatening viral disease endemic to tropical and subtropical regions of Africa and South America. YF has largely been controlled by widespread national vaccination campaigns. Nevertheless, between December 2015 and August 2016, YF resurged in Angola, quickly spread and became the largest YF outbreak for the last 30 years. Recently, YF resurged again in Brazil (December 2016). Thus, there is an urgent need to gain better understanding of the transmission pattern of YF. MODEL The present study provides a refined mathematical model, combined with modern likelihood-based statistical inference techniques, to assess and reconstruct important epidemiological processes underlying Angola's YF outbreak. This includes the outbreak's attack rate, the reproduction number ([Formula: see text]), the role of the mosquito vector, the influence of climatic factors, and the unusual but noticeable appearance of two-waves in the YF outbreak. The model explores actual and hypothetical vaccination strategies, and the impacts of possible human reactive behaviors (e.g., response to media precautions). FINDINGS While there were 73 deaths reported over the study period, the model indicates that the vaccination campaign saved 5.1-fold more people from death and saved from illness 5.6-fold of the observed 941 cases. Delaying the availability of the vaccines further would have greatly worsened the epidemic in terms of increased cases and deaths. The analysis estimated a mean [Formula: see text] and an attack rate of 0.09-0.15% (proportion of population infected) over the whole period from December 2015 to August 2016. Our estimated lower and upper bounds of [Formula: see text] are in line with previous studies. Unusually, [Formula: see text] oscillated in a manner that was "delayed" with the reported deaths. High recent number of deaths were associated (followed) with periods of relatively low disease transmission and low [Formula: see text], and vice-versa. The time-series of Luanda's YF cases suggest the outbreak occurred in two waves, a feature that would have become far more prominent had there been no mass vaccination. The waves could possibly be due to protective reactive behavioral changes of the population affecting the mosquito population. The second wave could well be an outcome of the March-April rainfall patterns in the 2016 El Niño year by creating ideal conditions for the breeding of the mosquito vectors. The modelling framework is a powerful tool for studying future YF epidemic outbreaks, and provides a basis for future vaccination campaign evaluations.
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Affiliation(s)
- Shi Zhao
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
| | - Lewi Stone
- School of Mathematical and Geospatial Sciences, RMIT University, Melbourne, Australia
- Biomathematics Unit, Department of Zoology, Tel Aviv University, Ramat Aviv, Israel
| | - Daozhou Gao
- Department of Mathematics, Shanghai Normal University, Shanghai, China
| | - Daihai He
- Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China
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Winnicka L, Abdullah A, Yang T, Norville K, Irizarry-Acosta M. Yellow Fever in an Unvaccinated Traveler to Peru. Open Forum Infect Dis 2017; 4:ofx205. [PMID: 29308400 PMCID: PMC5740984 DOI: 10.1093/ofid/ofx205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/16/2017] [Indexed: 11/29/2022] Open
Abstract
We present a case of an unvaccinated traveler who traveled from New York to Peru and contracted yellow fever. He likely acquired the infection while visiting the Amazon River, with a point of exit of Lima, Peru. Our case illustrates the dramatic course that yellow fever may take, as well as the importance of pretravel vaccination.
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Affiliation(s)
- Lydia Winnicka
- Department of Internal Medicine, Guthrie Clinic, Sayre, Pennsylvania
| | | | - Tsujung Yang
- Department of Internal Medicine, Guthrie Clinic, Sayre, Pennsylvania
| | - Kim Norville
- Department of Internal Medicine, Guthrie Clinic, Sayre, Pennsylvania
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Hamrick PN, Aldighieri S, Machado G, Leonel DG, Vilca LM, Uriona S, Schneider MC. Geographic patterns and environmental factors associated with human yellow fever presence in the Americas. PLoS Negl Trop Dis 2017; 11:e0005897. [PMID: 28886023 PMCID: PMC5607216 DOI: 10.1371/journal.pntd.0005897] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 09/20/2017] [Accepted: 08/22/2017] [Indexed: 11/24/2022] Open
Abstract
Background In the Americas, yellow fever virus transmission is a latent threat due to the proximity between urban and wild environments. Although yellow fever has nearly vanished from North and Central America, there are still 13 countries in the Americas considered endemic by the World Health Organization. Human cases usually occur as a result of the exposure to sylvatic yellow fever in tropical forested environments; but urban outbreaks reported during the last decade demonstrate that the risk in this environment still exists. The objective of this study was to identify spatial patterns and the relationship between key geographic and environmental factors with the distribution of yellow fever human cases in the Americas. Methodology/Principal findings An ecological study was carried out to analyze yellow fever human cases reported to the Pan American Health Organization from 2000 to 2014, aggregated by second administrative level subdivisions (counties). Presence of yellow fever by county was used as the outcome variable and eight geo-environmental factors were used as independent variables. Spatial analysis was performed to identify and examine natural settings per county. Subsequently, a multivariable logistic regression model was built. During the study period, 1,164 cases were reported in eight out of the 13 endemic countries. Nearly 83.8% of these cases were concentrated in three countries: Peru (37.4%), Brazil (28.1%) and Colombia (18.4%); and distributed in 57 states/provinces, specifically in 286 counties (3.4% of total counties). Yellow fever presence was significantly associated with altitude, rain, diversity of non-human primate hosts and temperature. A positive spatial autocorrelation revealed a clustered geographic pattern in 138/286 yellow fever positive counties (48.3%). Conclusions/Significance A clustered geographic pattern of yellow fever was identified mostly along the Andes eastern foothills. This risk map could support health policies in endemic countries. Geo-environmental factors associated with presence of yellow fever could help predict and adjust the limits of other risk areas of epidemiological concern. Yellow fever (YF) is a zoonotic disease caused by yellow fever virus (YFV), which is transmitted to humans through the bite of an infected mosquito. Sylvatic and urban cycles have been present in different periods, but currently most cases result from human exposure to jungle or forested environments. The World Health Organization considers 13 countries endemic for YFV in the Americas. The objective of this study was to identify spatial patterns and the relationship between key geographic and environmental factors with the distribution of YF human cases in the Americas. Cases of YF from 2000 to 2014 aggregated by county and eight geo-environmental factors were studied via spatial and statistical analysis. A total of 1,164 cases were reported in this time period, with the majority of them located in Peru, Brazil and Colombia. Yellow fever presence was associated with rain, altitude, diversity of non-human primate hosts and temperature. A large clustered geographic pattern of YF cases was identified along the Andes eastern foothills. Although YF cases can be seen as rare events, the results of this study demonstrate that YF human cases in the Americas are geographically concentrated and are not happening at random, even within areas known to be at risk. Determining the geo-environmental factors related to YFV is essential to delineate risk areas and to consequently improve resource allocation and prevent human cases.
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Affiliation(s)
- Patricia Najera Hamrick
- PAHO Health Emergencies Department, Pan American Health Organization, Washington D.C., United States of America
- * E-mail:
| | - Sylvain Aldighieri
- PAHO Health Emergencies Department, Pan American Health Organization, Washington D.C., United States of America
| | - Gustavo Machado
- Veterinary Population Medicine Department, University of Minnesota, Saint Paul, Minnesota, United States of America
| | - Deise Galan Leonel
- PAHO Health Emergencies Department, Pan American Health Organization, Washington D.C., United States of America
| | - Luz Maria Vilca
- Preventive Medicine and Epidemiology Department, Hospital Universitari Vall d’Hebron, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Sonia Uriona
- Preventive Medicine and Epidemiology Department, Hospital Universitari Vall d’Hebron, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Maria Cristina Schneider
- PAHO Health Emergencies Department, Pan American Health Organization, Washington D.C., United States of America
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Vector competence of populations of Aedes aegypti from three distinct cities in Kenya for chikungunya virus. PLoS Negl Trop Dis 2017; 11:e0005860. [PMID: 28820881 PMCID: PMC5576749 DOI: 10.1371/journal.pntd.0005860] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 08/30/2017] [Accepted: 08/07/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In April, 2004, chikungunya virus (CHIKV) re-emerged in Kenya and eventually spread to the islands in the Indian Ocean basin, South-East Asia, and the Americas. The virus, which is often associated with high levels of viremia in humans, is mostly transmitted by the urban vector, Aedes aegypti. The expansion of CHIKV presents a public health challenge both locally and internationally. In this study, we investigated the ability of Ae. aegypti mosquitoes from three distinct cities in Kenya; Mombasa (outbreak prone), Kisumu, and Nairobi (no documented outbreak) to transmit CHIKV. METHODOLOGY/PRINCIPAL FINDINGS Aedes aegypti mosquito populations were exposed to different doses of CHIKV (105.6-7.5 plaque-forming units[PFU]/ml) in an infectious blood meal. Transmission was ascertained by collecting and testing saliva samples from individual mosquitoes at 5, 7, 9, and 14 days post exposure. Infection and dissemination were estimated by testing body and legs, respectively, for individual mosquitoes at selected days post exposure. Tissue culture assays were used to determine the presence of infectious viral particles in the body, leg, and saliva samples. The number of days post exposure had no effect on infection, dissemination, or transmission rates, but these rates increased with an increase in exposure dose in all three populations. Although the rates were highest in Ae. aegypti from Mombasa at titers ≥106.9 PFU/ml, the differences observed were not statistically significant (χ2 ≤ 1.04, DF = 1, P ≥ 0.31). Overall, about 71% of the infected mosquitoes developed a disseminated infection, of which 21% successfully transmitted the virus into a capillary tube, giving an estimated transmission rate of about 10% for mosquitoes that ingested ≥106.9 PFU/ml of CHIKV. All three populations of Ae. aegypti were infectious as early as 5-7 days post exposure. On average, viral dissemination only occurred when body titers were ≥104 PFU/ml in all populations. CONCLUSIONS/SIGNIFICANCE Populations of Ae. aegypti from Mombasa, Nairobi, and Kisumu were all competent laboratory vectors of CHIKV. Viremia of the infectious blood meal was an important factor in Ae. aegypti susceptibility and transmission of CHIKV. In addition to viremia levels, temperature and feeding behavior of Ae. aegypti may also contribute to the observed disease patterns.
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Fine-scale variation in microclimate across an urban landscape shapes variation in mosquito population dynamics and the potential of Aedes albopictus to transmit arboviral disease. PLoS Negl Trop Dis 2017; 11:e0005640. [PMID: 28558030 PMCID: PMC5466343 DOI: 10.1371/journal.pntd.0005640] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 06/09/2017] [Accepted: 05/12/2017] [Indexed: 11/19/2022] Open
Abstract
Most statistical and mechanistic models used to predict mosquito-borne disease transmission incorporate climate drivers of disease transmission by utilizing environmental data collected at geographic scales that are potentially coarser than what mosquito populations may actually experience. Temperature and relative humidity can vary greatly between indoor and outdoor environments, and can be influenced strongly by variation in landscape features. In the Aedes albopictus system, we conducted a proof-of-concept study in the vicinity of the University of Georgia to explore the effects of fine-scale microclimate variation on mosquito life history and vectorial capacity (VC). We placed Ae. albopictus larvae in artificial pots distributed across three replicate sites within three different land uses–urban, suburban, and rural, which were characterized by high, intermediate, and low proportions of impervious surfaces. Data loggers were placed into each larval environment and in nearby vegetation to record daily variation in water and ambient temperature and relative humidity. The number of adults emerging from each pot and their body size and sex were recorded daily. We found mosquito microclimate to significantly vary across the season as well as with land use. Urban sites were in general warmer and less humid than suburban and rural sites, translating into decreased larval survival, smaller body sizes, and lower per capita growth rates of mosquitoes on urban sites. Dengue transmission potential was predicted to be higher in the summer than the fall. Additionally, the effects of land use on dengue transmission potential varied by season. Warm summers resulted in a higher predicted VC on the cooler, rural sites, while warmer, urban sites had a higher predicted VC during the cooler fall season. Environmental factors influence the dynamics of mosquito-borne disease transmission. Most models used to predict mosquito-borne disease transmission incorporate climate data collected at coarser scales than mosquitoes typically experience. Climate conditions can vary greatly between indoor and outdoor environments, and are influenced by landscape features. We conducted a field experiment with the Asian tiger mosquito to explore how microclimate variation across an urban landscape affects mosquito life history and potential to transmit arboviruses, like dengue. We demonstrate that climate conditions captured by weather stations do not reflect relevant mosquito microclimate, and that subtle variation in mean and diurnal ranges of temperature and relative humidity can lead to appreciable variation in key mosquito / pathogen traits that are important for transmission. Our results have implications for statistical and mechanistic models used to predict variation in transmission across seasons, regions, and land uses, but also for building in realistic environmental variation in laboratory work on mosquito-pathogen interactions. Finally, the variation in microclimate we observed across land use was subtle; likely because our study site is a relatively small city. Nevertheless, these translated into considerable differences in mosquito traits and dengue transmission potential, suggesting these effects could be much larger in more expansive cities.
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Abstract
Information about the Zika virus disease incubation period can help identify risk periods and local virus transmission. In 2015-2016, data from 197 symptomatic travelers with recent Zika virus infection indicated an estimated incubation period of 3-14 days. For symptomatic persons with symptoms >2 weeks after travel, transmission might be not travel associated.
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Shragai T, Tesla B, Murdock C, Harrington LC. Zika and chikungunya: mosquito-borne viruses in a changing world. Ann N Y Acad Sci 2017; 1399:61-77. [PMID: 28187236 DOI: 10.1111/nyas.13306] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/21/2016] [Accepted: 12/02/2016] [Indexed: 12/16/2022]
Abstract
The reemergence and growing burden of mosquito-borne virus infections have incited public fear and growing research efforts to understand the mechanisms of infection-associated health outcomes and to provide better approaches for mosquito vector control. While efforts to develop therapeutics, vaccines, and novel genetic mosquito-control technologies are underway, many important underlying ecological questions remain that could significantly enhance our understanding and ability to predict and prevent transmission. Here, we review the current knowledge about the transmission ecology of two recent arbovirus invaders, the chikungunya and Zika viruses. We introduce the viruses and mosquito vectors, highlighting viral biology, historical routes of transmission, and viral mechanisms facilitating rapid global invasion. In addition, we review factors contributing to vector global invasiveness and transmission efficiency. We conclude with a discussion of how human-induced biotic and abiotic environmental changes facilitate mosquito-borne virus transmission, emphasizing critical gaps in understanding. These knowledge gaps are tremendous; much of our data on basic mosquito ecology in the field predate 1960, and the mosquitoes themselves, as well as the world they live in, have substantially changed. A concerted investment in understanding the basic ecology of these vectors, which serve as the main drivers of pathogen transmission in both wildlife and human populations, is now more important than ever.
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Affiliation(s)
- Talya Shragai
- Department of Entomology, Cornell University, Ithaca, New York
| | - Blanka Tesla
- Department of Infectious Diseases and Odum School of Ecology, University of Georgia, Athens, Georgia
| | - Courtney Murdock
- Department of Infectious Diseases and Odum School of Ecology, University of Georgia, Athens, Georgia
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Wu JT, Peak CM, Leung GM, Lipsitch M. Fractional dosing of yellow fever vaccine to extend supply: a modelling study. Lancet 2016; 388:2904-2911. [PMID: 27837923 PMCID: PMC5161610 DOI: 10.1016/s0140-6736(16)31838-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/20/2016] [Accepted: 07/21/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND The ongoing yellow fever epidemic in Angola strains the global vaccine supply, prompting WHO to adopt dose sparing for its vaccination campaign in Kinshasa, Democratic Republic of the Congo, in July-August, 2016. Although a 5-fold fractional-dose vaccine is similar to standard-dose vaccine in safety and immunogenicity, efficacy is untested. There is an urgent need to ensure the robustness of fractional-dose vaccination by elucidation of the conditions under which dose fractionation would reduce transmission. METHODS We estimate the effective reproductive number for yellow fever in Angola using disease natural history and case report data. With simple mathematical models of yellow fever transmission, we calculate the infection attack rate (the proportion of population infected over the course of an epidemic) with various levels of transmissibility and 5-fold fractional-dose vaccine efficacy for two vaccination scenarios, ie, random vaccination in a hypothetical population that is completely susceptible, and the Kinshasa vaccination campaign in July-August, 2016, with different age cutoff for fractional-dose vaccines. FINDINGS We estimate the effective reproductive number early in the Angola outbreak was between 5·2 and 7·1. If vaccine action is all-or-nothing (ie, a proportion of vaccine recipients receive complete protection [VE] and the remainder receive no protection), n-fold fractionation can greatly reduce infection attack rate as long as VE exceeds 1/n. This benefit threshold becomes more stringent if vaccine action is leaky (ie, the susceptibility of each vaccine recipient is reduced by a factor that is equal to the vaccine efficacy). The age cutoff for fractional-dose vaccines chosen by WHO for the Kinshasa vaccination campaign (2 years) provides the largest reduction in infection attack rate if the efficacy of 5-fold fractional-dose vaccines exceeds 20%. INTERPRETATION Dose fractionation is an effective strategy for reduction of the infection attack rate that would be robust with a large margin for error in case fractional-dose VE is lower than expected. FUNDING NIH-MIDAS, HMRF-Hong Kong.
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Affiliation(s)
- Joseph T Wu
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
| | - Corey M Peak
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA
| | - Gabriel M Leung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA; Department of Immunology and Infectious Diseases, Harvard T H Chan School of Public Health, Boston, MA, USA
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Caljon G, De Muylder G, Durnez L, Jennes W, Vanaerschot M, Dujardin JC. Alice in microbes' land: adaptations and counter-adaptations of vector-borne parasitic protozoa and their hosts. FEMS Microbiol Rev 2016; 40:664-85. [PMID: 27400870 DOI: 10.1093/femsre/fuw018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2016] [Indexed: 12/24/2022] Open
Abstract
In the present review, we aim to provide a general introduction to different facets of the arms race between pathogens and their hosts/environment, emphasizing its evolutionary aspects. We focus on vector-borne parasitic protozoa, which have to adapt to both invertebrate and vertebrate hosts. Using Leishmania, Trypanosoma and Plasmodium as main models, we review successively (i) the adaptations and counter-adaptations of parasites and their invertebrate host, (ii) the adaptations and counter-adaptations of parasites and their vertebrate host and (iii) the impact of human interventions (chemotherapy, vaccination, vector control and environmental changes) on these adaptations. We conclude by discussing the practical impact this knowledge can have on translational research and public health.
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Affiliation(s)
- Guy Caljon
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium University of Antwerp, Department of Biomedical Sciences, Laboratory of Microbiology, Parasitology and Health, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Géraldine De Muylder
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium
| | - Lies Durnez
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium
| | - Wim Jennes
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium
| | - Manu Vanaerschot
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium Columbia University, College of Physicians and Surgeons, Department of Microbiology and Immunology, Fidock Lab, New York, NY 10032, USA
| | - Jean-Claude Dujardin
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, B-2000 Antwerp, Belgium University of Antwerp, Department of Biomedical Sciences, Laboratory of Microbiology, Parasitology and Health, Universiteitsplein 1, B-2610 Wilrijk, Belgium
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