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Bassey BE, Braka F, Onyibe R, Kolude OO, Oluwadare M, Oluwabukola A, Omotunde O, Iyanda OA, Tella AA, Olanike OS. Changing epidemiology of yellow fever virus in Oyo State, Nigeria. BMC Public Health 2022; 22:467. [PMID: 35260123 PMCID: PMC8903872 DOI: 10.1186/s12889-022-12871-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 02/16/2022] [Indexed: 11/21/2022] Open
Abstract
Background Yellow Fever is an acute viral hemorrhagic disease endemic in tropical Africa and Latin America and is transmitted through infected mosquitoes. The earliest outbreak of yellow fever in Nigeria was reported in Lagos in 1864 with subsequent regular outbreaks reported until 1996. A large epidemic of yellow fever occurred in Oyo State in April and May 1987 following an epidemic of sylvatic yellow fever in Eastern Nigeria the previous year. For 21 years, no further confirmed cases were reported until September 2017 following which Nigeria has been responding to successive outbreaks. The renewed onset of yellow fever outbreaks in Nigeria followed a global trend of reports and from other African countries. Yellow Fever disease has no cure, but control is through vaccination and vector control. Eliminating Yellow fever Epidemic (EYE) strategy to improve high-risk countries’ prevention, preparedness, detection, management, and response to yellow fever outbreaks was developed by the WHO in 2017 and launched in Nigeria in April 2018. Yet, poor vaccination coverage continues to be a cause for concern. Materials and methods We conducted a retrospective cross-sectional study that examines the resurgence of Yellow fever cases and outbreaks from 2013 to 2020 in Oyo State, Nigeria. The Yellow Fever data for both surveillance and routine Expanded Programme on Immunization (EPI) were the focus of the review. Surveillance data were retrieved from the State’s database reported by all 33 LGAs, maintained by the State and supported by the World Health Organization at the Zonal and State levels. The routine EPI data were retrieved from District Health Information Software (DHIS_2). The proportion of LGAs reporting at least one case of suspected yellow fever with a blood specimen and the number of suspected cases reported for each year within the period under review was measured. We also assessed the trend of confirmed cases and the incidence per 100,000 persons. Also, suspected cases of yellow fever were categorized into four age groups and their vaccination status was assessed. The State’s annual administrative routine vaccination coverage for yellow fever vaccine was compared with the number of confirmed cases for each year. Results The proportion of LGAs reporting at least a case of suspected yellow fever, with blood samples collected, ranged from 6.1 to 84.9% between 2014 and 2020 while a total of 9 confirmed (8 cases) and probable (1 case) cases of yellow fever were recorded. However, there were no confirmed cases from the year 2013 to 2016, including 2018 but an upward trend of incidence of the disease per 100,000 persons from 0% to 2013 through 2018, to 3.5% in 2019, and then to 5.6% in 2020 was observed. 93 of 240 (39%) suspected yellow fever cases reported during the given period were observed to have received yellow fever vaccine. Conclusions In conclusion, the increase in the circulation of the yellow fever virus in the state reiterates the state is at a high risk of yellow fever transmission and underlines the need for viable interventions such as environmental hygiene to rid the environment of the disease vector’s ecological niche and improving routine EPI coverage to provide population immunity.
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Affiliation(s)
- Bassey Enya Bassey
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria.
| | - Fiona Braka
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Rosemary Onyibe
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Olufunmilola Olawumi Kolude
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Marcus Oluwadare
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Alawale Oluwabukola
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Ogunlaja Omotunde
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Oluwatobi Adeoluwa Iyanda
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Adedamola Ayodeji Tella
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
| | - Olayiwola Suliat Olanike
- World Health Organization (WHO) Nigeria Country Office, UN House, Plot 617/618, Diplomatic Drive, Central Business District, PMB 2861, Garki, Abuja, Nigeria
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Nwaiwu AU, Musekiwa A, Tamuzi JL, Sambala EZ, Nyasulu PS. The incidence and mortality of yellow fever in Africa: a systematic review and meta-analysis. BMC Infect Dis 2021; 21:1089. [PMID: 34688249 PMCID: PMC8536483 DOI: 10.1186/s12879-021-06728-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/01/2021] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Understanding the occurrence of yellow fever epidemics is critical for targeted interventions and control efforts to reduce the burden of disease. We assessed data on the yellow fever incidence and mortality rates in Africa. METHODS We searched the Cochrane Library, SCOPUS, MEDLINE, CINAHL, PubMed, Embase, Africa-wide and Web of science databases from 1 January 1975 to 30th October 2020. Two authors extracted data from included studies independently and conducted a meta-analysis. RESULTS Of 840 studies identified, 12 studies were deemed eligible for inclusion. The incidence of yellow fever per 100,000 population ranged from < 1 case in Nigeria, < 3 cases in Uganda, 13 cases in Democratic Republic of the Congo, 27 cases in Kenya, 40 cases in Ethiopia, 46 cases in Gambia, 1267 cases in Senegal, and 10,350 cases in Ghana. Case fatality rate associated with yellow fever outbreaks ranged from 10% in Ghana to 86% in Nigeria. The mortality rate ranged from 0.1/100,000 in Nigeria to 2200/100,000 in Ghana. CONCLUSION The yellow fever incidence rate is quite constant; in contrast, the fatality rates vary widely across African countries over the study period. Standardized demographic health surveys and surveillance as well as accurate diagnostic measures are essential for early recognition, treatment and control.
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Affiliation(s)
- Akuoma U Nwaiwu
- Division of Epidemiology & Biostatistics, Faculty of Medicine & Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Alfred Musekiwa
- Division of Epidemiology & Biostatistics, Faculty of Medicine & Health Sciences, Stellenbosch University, Cape Town, South Africa
- School of Health Systems & Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Jacques L Tamuzi
- Division of Epidemiology & Biostatistics, Faculty of Medicine & Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Evanson Z Sambala
- Cochrane South Africa, South African Medical Research Council, Cape Town, South Africa
- School of Public Health and Family Medicine, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Peter S Nyasulu
- Division of Epidemiology & Biostatistics, Faculty of Medicine & Health Sciences, Stellenbosch University, Cape Town, South Africa.
- Division of Epidemiology & Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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Onwe FI, Okedo-Alex IN, Akamike IC, Igwe-Okomiso DO. Vertical disease programs and their effect on integrated disease surveillance and response: perspectives of epidemiologists and surveillance officers in Nigeria. Trop Dis Travel Med Vaccines 2021; 7:28. [PMID: 34593034 PMCID: PMC8483794 DOI: 10.1186/s40794-021-00152-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 08/23/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Integrated Disease Surveillance and Response (IDSR) is a cost-effective surveillance system designed to curb the inefficiency associated with vertical (disease-specific) programs. The study determined the existence and effect of vertical programs on disease surveillance and response in Nigeria. METHODS A cross-sectional study involving 14 State epidemiologists and Disease Notification Surveillance Officers (DSNOs) in 12 states located within the 6 geopolitical zones in Nigeria. Data was collected using mailed electronic semi-structured self-administered questionnaires. Response rate was 33.3%. The data was analyzed using SPSS version 20. RESULTS Half of the respondents were males (50.0%) and State epidemiologists (50.0%). Malaria, HIV/AIDS, tuberculosis, and other diseases were ongoing vertical programs in the States surveyed. In over 90% of cases, vertical programs had different personnel, communication channels and supportive supervision processes different from the IDSR system. Although less than 50% acknowledged the existence of a forum for data harmonization, this forum was ineffectively utilized in 83.3% of cases. Specific disease funding was higher than that of IDSR (92.9%) and only 42.9% reported funding for IDSR activities from development partners in the State. Poor data management, low priority on IDSR priority diseases, and donor-driven programming were major negative effects of vertical programs. Improved funding, political ownership, and integration were major recommendations preferred by the respondents. CONCLUSION We found that vertical programs in the surveyed States in the Nigerian health system led to duplication of efforts, inequitable funding, and inefficiencies in surveillance. We recommend integration of existing vertical programs into the IDSR system, increased resource allocation, and political support to improve IDSR.
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Affiliation(s)
- Francis Idenyi Onwe
- Ebonyi State Ministry of Health, Abakaliki, Nigeria
- Department of Community Medicine, Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi State, Nigeria
| | - Ijeoma Nkem Okedo-Alex
- Ebonyi State Ministry of Health, Abakaliki, Nigeria.
- Department of Community Medicine, Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi State, Nigeria.
- African Institute for Health Policy and Health Systems, Ebonyi State University, Abakaliki, Nigeria.
| | - Ifeyinwa Chizoba Akamike
- Department of Community Medicine, Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi State, Nigeria
- African Institute for Health Policy and Health Systems, Ebonyi State University, Abakaliki, Nigeria
| | - Dorothy Ogechi Igwe-Okomiso
- Department of Community Medicine, Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Ebonyi State, Nigeria
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Servadio JL, Muñoz-Zanzi C, Convertino M. Estimating case fatality risk of severe Yellow Fever cases: systematic literature review and meta-analysis. BMC Infect Dis 2021; 21:819. [PMID: 34399718 PMCID: PMC8365934 DOI: 10.1186/s12879-021-06535-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 08/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Case fatality risk (CFR), commonly referred to as a case fatality ratio or rate, represents the probability of a disease case being fatal. It is often estimated for various diseases through analysis of surveillance data, case reports, or record examinations. Reported CFR values for Yellow Fever vary, offering wide ranges. Estimates have not been found through systematic literature review, which has been used to estimate CFR of other diseases. This study aims to estimate the case fatality risk of severe Yellow Fever cases through a systematic literature review and meta-analysis. METHODS A search strategy was implemented in PubMed and Ovid Medline in June 2019 and updated in March 2021, seeking reported severe case counts, defined by fever and either jaundice or hemorrhaging, and the number of those that were fatal. The searches yielded 1,133 studies, and title/abstract review followed by full text review produced 14 articles reporting 32 proportions of fatal cases, 26 of which were suitable for meta-analysis. Four studies with one proportion each were added to include clinical case data from the recent outbreak in Brazil. Data were analyzed through an intercept-only logistic meta-regression with random effects for study. Values of the I2 statistic measured heterogeneity across studies. RESULTS The estimated CFR was 39 % (95 % CI: 31 %, 47 %). Stratifying by continent showed that South America observed a higher CFR than Africa, though fewer studies reported estimates for South America. No difference was seen between studies reporting surveillance data and studies investigating outbreaks, and no difference was seen among different symptom definitions. High heterogeneity was observed across studies. CONCLUSIONS Approximately 39 % of severe Yellow Fever cases are estimated to be fatal. This study provides the first systematic literature review to estimate the CFR of Yellow Fever, which can provide insight into outbreak preparedness and estimating underreporting.
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Affiliation(s)
- Joseph L Servadio
- Division of Environmental Health Sciences, University of Minnesota School of Public Health, 420 Delaware St SE, Minneapolis, 55401, MN, USA.
| | - Claudia Muñoz-Zanzi
- Division of Environmental Health Sciences, University of Minnesota School of Public Health, 420 Delaware St SE, Minneapolis, 55401, MN, USA
| | - Matteo Convertino
- Nexus Group and Gi-CORE, Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan
- Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, China
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Kuno G. The Absence of Yellow Fever in Asia: History, Hypotheses, Vector Dispersal, Possibility of YF in Asia, and Other Enigmas. Viruses 2020; 12:E1349. [PMID: 33255615 PMCID: PMC7759908 DOI: 10.3390/v12121349] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/12/2020] [Accepted: 11/17/2020] [Indexed: 01/11/2023] Open
Abstract
Since the recent epidemics of yellow fever in Angola and Brazil as well as the importation of cases to China in 2016, there has been an increased interest in the century-old enigma, absence of yellow fever in Asia. Although this topic has been repeatedly reviewed before, the history of human intervention has never been considered a critical factor. A two-stage literature search online for this review, however, yielded a rich history indispensable for the debate over this medical enigma. As we combat the pandemic of COVID-19 coronavirus worldwide today, we can learn invaluable lessons from the historical events in Asia. In this review, I explore the history first and then critically examine in depth major hypotheses proposed in light of accumulated data, global dispersal of the principal vector, patterns of YF transmission, persistence of urban transmission, and the possibility of YF in Asia. Through this process of re-examination of the current knowledge, the subjects for research that should be conducted are identified. This review also reveals the importance of holistic approach incorporating ecological and human factors for many unresolved subjects, such as the enigma of YF absence in Asia, vector competence, vector dispersal, spillback, viral persistence and transmission mechanisms.
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Affiliation(s)
- Goro Kuno
- Centers for Disease Control and Prevention, Formerly Division of Vector-Borne Infectious Diseases, Fort Collins, CO 80521, USA
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Safety profile of fractional dosing of the 17DD Yellow Fever Vaccine among males and females: Experience of a community-based pharmacovigilance in Kinshasa, DR Congo. Vaccine 2018; 36:6170-6182. [PMID: 30190119 DOI: 10.1016/j.vaccine.2018.08.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/24/2018] [Accepted: 08/21/2018] [Indexed: 11/24/2022]
Abstract
BACKGROUND In early 2016, there was a Yellow Fever (YF) outbreak in Central Africa with several deaths reported from Angola and the Democratic Republic of Congo. Due to a shortage in vaccine supply, fractional dosing (0.1 ml) of 17DD Yellow Fever Vaccine (YFV) was proposed in preventive vaccination campaign in Kinshasa in August 2016. A Pharmacovigilance surveillance at community level was implemented to track Adverse Events Following Immunization (AEFIs). The objective of this study was to describe AEFIs as captured from community-based pharmacovigilance and to compare the safety profile of the fractional dosing of YFV between gender. METHODS PV information sessions were organized in churches, academic institutions, and pediatrician, obstetrician and friend networks. Prior to data collection, education about AEFI was provided through face-to-face discussions, phone calls, SMS and WhatsApp messages. Individuals reported AEFIs though the above communication channels to assigned individuals. Reported AEFIs were entered into VigiFlow and extracted for statistical analysis using Stata 12. Only vaccinees who received fractional dose (subjects from the age of 2-year-old and non-pregnant women) were included in analysis. Proportional t-test was used to compare AEFI preferred terms among males and females. RESULTS A total of 4020 subjects reported 5409 AEFIs. Reporters were mostly males (54.9%) with an average age of 26 ± 10.7 years. Fever and injection site pain were the most reported systemic and local AEFI respectively. The safety profile was similar between gender although females reported more diarrhea and dizziness whilst males reported more asthenia (P < 0.001). Five individuals reported serious AEFIs. Among them, 4 were less-immunocompetent. CONCLUSION Fractional dosing of 17DD YFV has a good safety profile, which is similar between gender. These findings complement the documented immunogenicity profile to support recommendation of fractional dose of YFV for outbreak control.
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7
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Faria NR, Kraemer MUG, Hill SC, Goes de Jesus J, Aguiar RS, Iani FCM, Xavier J, Quick J, du Plessis L, Dellicour S, Thézé J, Carvalho RDO, Baele G, Wu CH, Silveira PP, Arruda MB, Pereira MA, Pereira GC, Lourenço J, Obolski U, Abade L, Vasylyeva TI, Giovanetti M, Yi D, Weiss DJ, Wint GRW, Shearer FM, Funk S, Nikolay B, Fonseca V, Adelino TER, Oliveira MAA, Silva MVF, Sacchetto L, Figueiredo PO, Rezende IM, Mello EM, Said RFC, Santos DA, Ferraz ML, Brito MG, Santana LF, Menezes MT, Brindeiro RM, Tanuri A, Dos Santos FCP, Cunha MS, Nogueira JS, Rocco IM, da Costa AC, Komninakis SCV, Azevedo V, Chieppe AO, Araujo ESM, Mendonça MCL, Dos Santos CC, Dos Santos CD, Mares-Guia AM, Nogueira RMR, Sequeira PC, Abreu RG, Garcia MHO, Abreu AL, Okumoto O, Kroon EG, de Albuquerque CFC, Lewandowski K, Pullan ST, Carroll M, de Oliveira T, Sabino EC, Souza RP, Suchard MA, Lemey P, Trindade GS, Drumond BP, Filippis AMB, Loman NJ, Cauchemez S, Alcantara LCJ, Pybus OG. Genomic and epidemiological monitoring of yellow fever virus transmission potential. Science 2018; 361:894-899. [PMID: 30139911 PMCID: PMC6874500 DOI: 10.1126/science.aat7115] [Citation(s) in RCA: 208] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 07/20/2018] [Indexed: 12/21/2022]
Abstract
The yellow fever virus (YFV) epidemic in Brazil is the largest in decades. The recent discovery of YFV in Brazilian Aedes species mosquitos highlights a need to monitor the risk of reestablishment of urban YFV transmission in the Americas. We use a suite of epidemiological, spatial, and genomic approaches to characterize YFV transmission. We show that the age and sex distribution of human cases is characteristic of sylvatic transmission. Analysis of YFV cases combined with genomes generated locally reveals an early phase of sylvatic YFV transmission and spatial expansion toward previously YFV-free areas, followed by a rise in viral spillover to humans in late 2016. Our results establish a framework for monitoring YFV transmission in real time that will contribute to a global strategy to eliminate future YFV epidemics.
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Affiliation(s)
- N R Faria
- Department of Zoology, University of Oxford, Oxford, UK.
| | - M U G Kraemer
- Department of Zoology, University of Oxford, Oxford, UK
- Computational Epidemiology Lab, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - S C Hill
- Department of Zoology, University of Oxford, Oxford, UK
| | - J Goes de Jesus
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - R S Aguiar
- Laboratório de Virologia Molecular, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - F C M Iani
- Laboratório Central de Saúde Pública, Instituto Octávio Magalhães, FUNED, Belo Horizonte, Minas Gerais, Brazil
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - J Xavier
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - J Quick
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - L du Plessis
- Department of Zoology, University of Oxford, Oxford, UK
| | - S Dellicour
- Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium
| | - J Thézé
- Department of Zoology, University of Oxford, Oxford, UK
| | - R D O Carvalho
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - G Baele
- Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium
| | - C-H Wu
- Department of Statistics, University of Oxford, Oxford, UK
| | - P P Silveira
- Laboratório de Virologia Molecular, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M B Arruda
- Laboratório de Virologia Molecular, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M A Pereira
- Laboratório Central de Saúde Pública, Instituto Octávio Magalhães, FUNED, Belo Horizonte, Minas Gerais, Brazil
| | - G C Pereira
- Laboratório Central de Saúde Pública, Instituto Octávio Magalhães, FUNED, Belo Horizonte, Minas Gerais, Brazil
| | - J Lourenço
- Department of Zoology, University of Oxford, Oxford, UK
| | - U Obolski
- Department of Zoology, University of Oxford, Oxford, UK
| | - L Abade
- Department of Zoology, University of Oxford, Oxford, UK
- The Global Health Network, University of Oxford, Oxford, UK
| | - T I Vasylyeva
- Department of Zoology, University of Oxford, Oxford, UK
| | - M Giovanetti
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - D Yi
- Department of Statistics, Harvard University, Cambridge, MA, USA
| | - D J Weiss
- Malaria Atlas Project, Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - G R W Wint
- Department of Zoology, University of Oxford, Oxford, UK
| | - F M Shearer
- Malaria Atlas Project, Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - S Funk
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - B Nikolay
- Mathematical Modelling of Infectious Diseases and Center of Bioinformatics, Institut Pasteur, Paris, France
- CNRS UMR2000: Génomique Évolutive, Modélisation et Santé, Institut Pasteur, Paris, France
| | - V Fonseca
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- KwaZulu-Natal Research, Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - T E R Adelino
- Laboratório Central de Saúde Pública, Instituto Octávio Magalhães, FUNED, Belo Horizonte, Minas Gerais, Brazil
| | - M A A Oliveira
- Laboratório Central de Saúde Pública, Instituto Octávio Magalhães, FUNED, Belo Horizonte, Minas Gerais, Brazil
| | - M V F Silva
- Laboratório Central de Saúde Pública, Instituto Octávio Magalhães, FUNED, Belo Horizonte, Minas Gerais, Brazil
| | - L Sacchetto
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - P O Figueiredo
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - I M Rezende
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - E M Mello
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - R F C Said
- Secretaria de Estado de Saúde de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - D A Santos
- Secretaria de Estado de Saúde de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - M L Ferraz
- Secretaria de Estado de Saúde de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - M G Brito
- Secretaria de Estado de Saúde de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - L F Santana
- Secretaria de Estado de Saúde de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - M T Menezes
- Laboratório de Virologia Molecular, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - R M Brindeiro
- Laboratório de Virologia Molecular, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - A Tanuri
- Laboratório de Virologia Molecular, Departamento de Genética, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - F C P Dos Santos
- Núcleo de Doenças de Transmissão Vetorial, Instituto Adolfo Lutz, São Paulo, Brazil
| | - M S Cunha
- Núcleo de Doenças de Transmissão Vetorial, Instituto Adolfo Lutz, São Paulo, Brazil
| | - J S Nogueira
- Núcleo de Doenças de Transmissão Vetorial, Instituto Adolfo Lutz, São Paulo, Brazil
| | - I M Rocco
- Núcleo de Doenças de Transmissão Vetorial, Instituto Adolfo Lutz, São Paulo, Brazil
| | - A C da Costa
- Instituto de Medicina Tropical e Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - S C V Komninakis
- Retrovirology Laboratory, Federal University of São Paulo, São Paulo, Brazil
- School of Medicine of ABC (FMABC), Clinical Immunology Laboratory, Santo André, São Paulo, Brazil
| | - V Azevedo
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - A O Chieppe
- Coordenação de Vigilância Epidemiológica do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - E S M Araujo
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - M C L Mendonça
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - C C Dos Santos
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - C D Dos Santos
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - A M Mares-Guia
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - R M R Nogueira
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - P C Sequeira
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - R G Abreu
- Departamento de Vigilância das Doenças Transmissíveis da Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasília-DF, Brazil
| | - M H O Garcia
- Departamento de Vigilância das Doenças Transmissíveis da Secretaria de Vigilância em Saúde, Ministério da Saúde, Brasília-DF, Brazil
| | - A L Abreu
- Secretaria de Vigilância em Saúde, Coordenação Geral de Laboratórios de Saúde Pública, Ministério da Saúde, Brasília-DF, Brazil
| | - O Okumoto
- Secretaria de Vigilância em Saúde, Coordenação Geral de Laboratórios de Saúde Pública, Ministério da Saúde, Brasília-DF, Brazil
| | - E G Kroon
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - C F C de Albuquerque
- Organização Pan - Americana da Saúde/Organização Mundial da Saúde - (OPAS/OMS), Brasília-DF, Brazil
| | - K Lewandowski
- Public Health England, National Infections Service, Porton Down, Salisbury, UK
| | - S T Pullan
- Public Health England, National Infections Service, Porton Down, Salisbury, UK
| | - M Carroll
- NIHR HPRU in Emerging and Zoonotic Infections, Public Health England, London, UK
| | - T de Oliveira
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- KwaZulu-Natal Research, Innovation and Sequencing Platform (KRISP), School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), Durban, South Africa
| | - E C Sabino
- Instituto de Medicina Tropical e Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - R P Souza
- Núcleo de Doenças de Transmissão Vetorial, Instituto Adolfo Lutz, São Paulo, Brazil
| | - M A Suchard
- Department of Biostatistics, UCLA Fielding School of Public Health, University of California, Los Angeles, CA, USA
- Department of Biomathematics and Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA
| | - P Lemey
- Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium
| | - G S Trindade
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - B P Drumond
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - A M B Filippis
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - N J Loman
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - S Cauchemez
- Mathematical Modelling of Infectious Diseases and Center of Bioinformatics, Institut Pasteur, Paris, France
- CNRS UMR2000: Génomique Évolutive, Modélisation et Santé, Institut Pasteur, Paris, France
| | - L C J Alcantara
- Laboratório de Flavivírus, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil.
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - O G Pybus
- Department of Zoology, University of Oxford, Oxford, UK.
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Njidda AM, Oyebanji O, Obasanya J, Ojo O, Adedeji A, Mba N, Oladejo J, Ihekweazu C. The Nigeria Centre for Disease Control. BMJ Glob Health 2018; 3:e000712. [PMID: 29707246 PMCID: PMC5914765 DOI: 10.1136/bmjgh-2018-000712] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 02/27/2018] [Accepted: 03/11/2018] [Indexed: 11/06/2022] Open
Affiliation(s)
| | | | | | - Olubunmi Ojo
- Nigeria Centre for Disease Control, Abuja, Nigeria
| | | | - Nwando Mba
- Nigeria Centre for Disease Control, Abuja, Nigeria
| | - John Oladejo
- Nigeria Centre for Disease Control, Abuja, Nigeria
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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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Peña-García VH, McCracken MK, Christofferson RC. Examining the potential for South American arboviruses to spread beyond the New World. CURRENT CLINICAL MICROBIOLOGY REPORTS 2017; 4:208-217. [PMID: 29785356 DOI: 10.1007/s40588-017-0076-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Zika and chikungunya viruses emerged as public health emergencies in the Western Hemisphere where previously they had not been reported on a large scale. Millions were infected as the viruses met with virtually no herd immunity upon emergence. Purpose of the Review We explore the histories of these two recent arbovirus experiences in South America. We then review similarly three endemic South American viruses: yellow fever, Oropouche, and Mayaro viruses. Recent Findings We discuss the commonalities of the transmission systems and the possibility of an atypical emergence, that of New World virus to the Old World. Summary We discuss the avenues for research that would increase preparedness and efficiency of response should a South American arbovirus emerge in the Eastern Hemisphere.
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Affiliation(s)
- Víctor Hugo Peña-García
- Department of Biology and Microbiology, Faculty of Science and Engineering, University of Boyacá, Tunja, Boyacá, Colombia
| | - Michael K McCracken
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, USA
| | - Rebecca C Christofferson
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana 70803, USA
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Agha SB, Tchouassi DP, Bastos ADS, Sang R. Assessment of risk of dengue and yellow fever virus transmission in three major Kenyan cities based on Stegomyia indices. PLoS Negl Trop Dis 2017; 11:e0005858. [PMID: 28817563 PMCID: PMC5574621 DOI: 10.1371/journal.pntd.0005858] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 08/29/2017] [Accepted: 08/07/2017] [Indexed: 11/18/2022] Open
Abstract
Dengue (DEN) and yellow fever (YF) are re-emerging in East Africa, with contributing drivers to this trend being unplanned urbanization and increasingly adaptable anthropophilic Aedes (Stegomyia) vectors. Entomological risk assessment of these diseases remains scarce for much of East Africa and Kenya even in the dengue fever-prone urban coastal areas. Focusing on major cities of Kenya, we compared DEN and YF risk in Kilifi County (DEN-outbreak-prone), and Kisumu and Nairobi Counties (no documented DEN outbreaks). We surveyed water-holding containers for mosquito immature (larvae/pupae) indoors and outdoors from selected houses during the long rains, short rains and dry seasons (100 houses/season) in each County from October 2014-June 2016. House index (HI), Breteau index (BI) and Container index (CI) estimates based on Aedes (Stegomyia) immature infestations were compared by city and season. Aedes aegypti and Aedes bromeliae were the main Stegomyia species with significantly more positive houses outdoors (212) than indoors (88) (n = 900) (χ2 = 60.52, P < 0.0001). Overall, Ae. aegypti estimates of HI (17.3 vs 11.3) and BI (81.6 vs 87.7) were higher in Kilifi and Kisumu, respectively, than in Nairobi (HI, 0.3; BI,13). However, CI was highest in Kisumu (33.1), followed by Kilifi (15.1) then Nairobi (5.1). Aedes bromeliae indices were highest in Kilifi, followed by Kisumu, then Nairobi with HI (4.3, 0.3, 0); BI (21.3, 7, 0.7) and CI (3.3, 3.3, 0.3), at the respective sites. HI and BI for both species were highest in the long rains, compared to the short rains and dry seasons. We found strong positive correlations between the BI and CI, and BI and HI for Ae. aegypti, with the most productive container types being jerricans, drums, used/discarded containers and tyres. On the basis of established vector index thresholds, our findings suggest low-to-medium risk levels for urban YF and high DEN risk for Kilifi and Kisumu, whereas for Nairobi YF risk was low while DEN risk levels were low-to-medium. The study provides a baseline for future vector studies needed to further characterise the observed differential risk patterns by vector potential evaluation. Identified productive containers should be made the focus of community-based targeted vector control programs. Despite the growing problem of dengue (DEN) and yellow fever (YF) evidenced from recent outbreaks in East Africa, risk assessment for their transmission and establishment through surveys of populations of the Aedes mosquito vectors, remain scarce. By estimating standard indices for the potential vectors, Aedes aegypti and Aedes bromeliae we partly could deduce the risk of transmission of these diseases in three major cities of Kenya, namely Kilifi (DEN-prone) and Kisumu and Nairobi (without any DEN outbreak reports). When compared to established threshold risk levels by WHO and PAHO, our findings suggest low-to-medium risk of urban YF, and high risk of DEN transmission for Kilifi and Kisumu but not Nairobi (low risk level for YF and low-to-medium risk for DEN). The observed seasonal risk patterns, higher Aedes infestation outdoors than indoors and productive container types (jerricans, drums, discarded containers and tyres), provide insights into the disease epidemiology and are valuable for targeted vector control, respectively.
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Affiliation(s)
- Sheila B. Agha
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- * E-mail: ,
| | | | - Armanda D. S. Bastos
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Arbovirus/Viral Hemorrhagic Fever Laboratory, Centre for Virus Research, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
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12
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Victor OA, Adekunle AJ, Tahiru IK, David OO. Influence of Meteorological Variables on Diversity and Abundance of Mosquito Vectors in Two Livestock Farms in Ibadan, Nigeria: Public Health Implications. ACTA ACUST UNITED AC 2017; 7:70-78. [PMID: 28845206 PMCID: PMC5570447 DOI: 10.5376/jmr.2017.07.0009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study was undertaken to determine mosquito vector diversity and abundance in two livestock farms with previous history of arboviral activities in Ibadan, southwestern Nigeria. The influence of weather on mosquito populations was also studied. Adult mosquitoes were collected weekly in two proximate University of Ibadan livestock farms from March 2015 to February 2016 using CO2 baited CDC light trap and human landing collection methods. Mosquitoes were identified to species using morphological keys. Relationships and interaction of temperature, relative humidity, rainfall patterns and mosquito abundance were analysed using GENSTAT 4th edition. Among 6,195 adult mosquitoes collected, 16 species belonging to 5 genera were morphologically identified. Culex quinquefasciatus constituted the most abundant mosquito, representing 46.49% of all mosquitoes encountered. High abundance in mosquito population was noted in periods succeeding months with heavy rainfall, this is when arbovirus transmission risk is highest. A positive correlation was observed between relative humidity and abundance of Mansonia mosquitoes. This study shows the effect of weather on natural populations of mosquito vectors. The diverse mosquito species capable of transmitting arboviruses from animal reservoirs to human and animals in livestock farms and its environment in Ibadan, Nigeria was also revealed. There is need for intensive vector control strategies targeted at reducing mosquito populations and ultimately prevention of disease outbreaks.
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13
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Crawford JE, Alves JM, Palmer WJ, Day JP, Sylla M, Ramasamy R, Surendran SN, Black WC, Pain A, Jiggins FM. Population genomics reveals that an anthropophilic population of Aedes aegypti mosquitoes in West Africa recently gave rise to American and Asian populations of this major disease vector. BMC Biol 2017; 15:16. [PMID: 28241828 PMCID: PMC5329927 DOI: 10.1186/s12915-017-0351-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/19/2017] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The mosquito Aedes aegypti is the main vector of dengue, Zika, chikungunya and yellow fever viruses. This major disease vector is thought to have arisen when the African subspecies Ae. aegypti formosus evolved from being zoophilic and living in forest habitats into a form that specialises on humans and resides near human population centres. The resulting domestic subspecies, Ae. aegypti aegypti, is found throughout the tropics and largely blood-feeds on humans. RESULTS To understand this transition, we have sequenced the exomes of mosquitoes collected from five populations from around the world. We found that Ae. aegypti specimens from an urban population in Senegal in West Africa were more closely related to populations in Mexico and Sri Lanka than they were to a nearby forest population. We estimate that the populations in Senegal and Mexico split just a few hundred years ago, and we found no evidence of Ae. aegypti aegypti mosquitoes migrating back to Africa from elsewhere in the tropics. The out-of-Africa migration was accompanied by a dramatic reduction in effective population size, resulting in a loss of genetic diversity and rare genetic variants. CONCLUSIONS We conclude that a domestic population of Ae. aegypti in Senegal and domestic populations on other continents are more closely related to each other than to other African populations. This suggests that an ancestral population of Ae. aegypti evolved to become a human specialist in Africa, giving rise to the subspecies Ae. aegypti aegypti. The descendants of this population are still found in West Africa today, and the rest of the world was colonised when mosquitoes from this population migrated out of Africa. This is the first report of an African population of Ae. aegypti aegypti mosquitoes that is closely related to Asian and American populations. As the two subspecies differ in their ability to vector disease, their existence side by side in West Africa may have important implications for disease transmission.
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Affiliation(s)
- Jacob E Crawford
- Department of Integrative Biology, University of California, Berkeley, CA, 94720-3140, USA
- Present Address: Verily Life Sciences, South San Francisco, CA, 94080, USA
| | - Joel M Alves
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, Universidade do Porto, 4485-661, Vairão, Portugal
| | - William J Palmer
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Jonathan P Day
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Massamba Sylla
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | | | - Sinnathamby N Surendran
- ID-FISH Technology, Palo Alto, CA, 94303, USA
- Department of Zoology, University of Jaffna, Jaffna, Sri Lanka
| | - William C Black
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Arnab Pain
- Biological and Environmental Sciences and Engineering Division, KAUST, Thuwal, Kingdom of Saudi Arabia
| | - Francis M Jiggins
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
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Wilder-Smith A, Monath TP. Responding to the threat of urban yellow fever outbreaks. THE LANCET. INFECTIOUS DISEASES 2016; 17:248-250. [PMID: 28017560 DOI: 10.1016/s1473-3099(16)30588-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/05/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Annelies Wilder-Smith
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore; Fondation Mérieux, Lyon, France; Institute of Public Health, University of Heidelberg, Heidelberg, Germany
| | - Thomas P Monath
- BioProtection Systems/NewLink Genetics Corp, Devens, MA, USA
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Agwu EJ, Igbinosa IB, Isaac C. Entomological assessment of yellow fever-epidemic risk indices in Benue State, Nigeria, 2010-2011. Acta Trop 2016; 161:18-25. [PMID: 27189925 DOI: 10.1016/j.actatropica.2016.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/06/2016] [Accepted: 05/07/2016] [Indexed: 10/21/2022]
Abstract
Yellow fever (YF) is a vector-borne disease affecting humans and non-human primates in tropical areas. In the past, there have been pockets of YF outbreaks in Nigeria that resulted in preventable deaths. Surveillance efforts towards avoiding another outbreak have been put in place with the aim of early detection and control. However, risk indices relating to the density of immature YF-mosquito vectors are given little consideration even though it is the first step in curbing a possible outbreak. Immature collections from 1538 houses in Ega, Oju, Otukpoicho and Otukpo in Benue State were carried out in 2010 and 2011. Risk indices such as house index (HI), container index (CI) and Breteau index (BI) were estimated. Molecular detection of YF was carried out on randomly selected Aedes larvae and pupae. Overall, 431,381 mosquitoes were collected in and around house premises. Thirteen species were identified: Ae. aegypti (Linneaus), Ae. africanus (Theobald), Ae. albopictus (Skuse), Ae. cumminsii (Theobald), Ae. luteocephalus (Newstead), Ae. simpsoni s.l. (Theobald), Ae. vittatus (Bigot), Anopheles gambiae Giles, An. nili (Theobald), Cx. nebulosus Theobald, Culex quinquefasciatus Say, Lutzia tigripes (Grandpre and Charmoy) and Toxorhynchites brevipalpis Theobald. The HI, CI and BI for Ae. aegypti were high in all the study locations, but low for Ae. lueteocephalus except in Ega. With 50 immature Aedes mosquitoes screened across locations, only Ae. aegypti from Ega were positive for YF. This study places Ega on a high alert of an impending YF outbreak. Thus, urgent steps to clear this area of potential mosquito sites are highly recommended.
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Dickson LB, Sharakhova MV, Timoshevskiy VA, Fleming KL, Caspary A, Sylla M, Black WC. Reproductive Incompatibility Involving Senegalese Aedes aegypti (L) Is Associated with Chromosome Rearrangements. PLoS Negl Trop Dis 2016; 10:e0004626. [PMID: 27105225 PMCID: PMC4841568 DOI: 10.1371/journal.pntd.0004626] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/23/2016] [Indexed: 01/16/2023] Open
Abstract
Aedes aegypti, the primary vector of dengue, yellow fever and Zika flaviviruses, consists of at least two subspecies. Aedes aegypti (Aaa) is light in color, has pale scales on the first abdominal tergite, oviposits in artificial containers, and preferentially feeds on humans. Aedes aegypti formosus (Aaf), has a dark cuticle, is restricted to sub-Saharan Africa, has no pale scales on the first abdominal tergite and frequently oviposits in natural containers. Scale patterns correlate with cuticle color in East Africa but not in Senegal, West Africa where black cuticle mosquitoes display a continuum of scaling patterns and breed domestically indoors. An earlier laboratory study did not indicate any pre- or postzygotic barriers to gene flow between Aaa and Aaf in East Africa. However, similar attempts to construct F1 intercross families between Aaa laboratory strains and Senegal Ae. aegypti (SenAae) failed due to poor F1 oviposition and low F2 egg-to-adult survival. Insemination and assortative mating experiments failed to identify prezygotic mating barriers. Backcrosses were performed to test for postzygotic isolation patterns consistent with Haldane’s rule modified for species, like Aedes, that have an autosomal sex determining locus (SDL). Egg-pupal survival was predicted to be low in females mated to hybrid F1 males but average when a male mates with a hybrid F1 female. Survival was in fact significantly reduced when females mated to hybrid males but egg-pupal survival was significantly increased when males were mated to hybrid F1 females. These observations are therefore inconclusive with regards to Haldane’s rule. Basic cytogenetic analyses and Fluorescent In Situ Hybridization (FISH) experiments were performed to compare SenAae strains with the IB12 strain of Aaa that was used for genome sequencing and physical mapping. Some SenAae strains had longer chromosomes than IB12 and significantly different centromeric indices on chromosomes 1 and 3. DAPI staining was used to identify AT-rich regions, chromomycin A3 following pretreatment with barium hydroxide stained for GC-rich regions and stained the ribosomal RNA locus and YOYO-1 was used to test for differential staining. Chromosome patterns in SenAae strains revealed by these three stains differed from those in IB12. For FISH, 40 BAC clones previously physically mapped on Aaa chromosomes were used to test for chromosome rearrangements in SenAae relative to IB12. Differences in the order of markers identified two chromosomal rearrangements between IB12 and SenAae strains. The first rearrangement involves two overlapping pericentric (containing the centromere) inversions in chromosome 3 or an insertion of a large fragment into the 3q arm. The second rearrangement is close to the centromere on the p arm of chromosome 2. Linkage analysis of the SDL and the white-eye locus identified a likely chromosomal rearrangement on chromosome 1. The reproductive incompatibility observed within SenAae and between SenAae and Aaa may be generally associated with chromosome rearrangements on all three chromosomes and specifically caused by pericentric inversions on chromosomes 2 and 3. Aedes aegypti is one of the best studied mosquito species and it is the principal vector of dengue, Zika, and yellow fever flaviviruses and the Chikungunya alphavirus. Aedes aegypti occurs throughout all tropical and subtropical regions of the world, and previous population genetic studies have shown that the highest genetic diversity occurs in Africa. Aedes aegypti from Senegal, West Africa (SenAae) have a low oviposition rate; those that do oviposit have a low fecundity and poor egg-to-adult survival. Furthermore rearrangements were detected on all three chromosomes in SenAae. These observations are consistent with the presence of at least two cryptic subspecies of Ae. aegypti in Senegal arising from reproductive isolation due to chromosome rearrangements. Genetic control strategies are being considered for the suppression of Ae. aegypti populations worldwide. Barriers to gene flow in African Ae. aegypti populations could compromise these future control efforts.
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Affiliation(s)
- Laura B. Dickson
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Maria V. Sharakhova
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Vladimir A. Timoshevskiy
- Department of Entomology, Fralin Life Science Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Karen L. Fleming
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Alex Caspary
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Massamba Sylla
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - William C. Black
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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Monath TP, Woodall JP, Gubler DJ, Yuill TM, Mackenzie JS, Martins RM, Reiter P, Heymann DL. Yellow fever vaccine supply: a possible solution. Lancet 2016; 387:1599-600. [PMID: 27116054 DOI: 10.1016/s0140-6736(16)30195-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
| | - Jack P Woodall
- ProMED, International Society for Infectious Diseases, Brookline, MA, USA
| | - Duane J Gubler
- Department of Tropical Medicine, Duke-NUS Graduate Medical School, Singapore
| | - Thomas M Yuill
- Pathobiological Science, Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI, USA
| | - John S Mackenzie
- Tropical Infectious Diseases, Curtin University, Perth, WA, Australia
| | | | | | - David L Heymann
- Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK.
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Motayo BO, Onoja BA, Faneye AO, Adeniji JA. Seasonal abundance and molecular identification of West Nile virus vectors, Culex pipens and Culex quinquefasciatus (diptera: culicidae) in Abeokuta, South-West, Nigeria. Afr Health Sci 2016; 16:135-40. [PMID: 27358624 PMCID: PMC4915403 DOI: 10.4314/ahs.v16i1.18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND West Nile virus (WNV) infection, is an arbovirus infection with high morbidity and mortality, the vector responsible for both human and animal transmission is Culex pipens complex. OBJECTIVE To determine the species distribution and seasonal abundance of Culex pipens and Culex quinquefasciatus mosquitoes in Abeokuta, Nigeria. METHODS Mosquitoes belonging to the Culex pipens complex were captured in three different locations located within Abeokuta Metropolis between March 2012 and January 2013. Individual species were identified using morphometric methods. Amplification of the Ace2 gene by PCR confirmed morphormetric identification of the mosquitoes. RESULTS A total of 751 mosquitoes were captured. Culex quinquefaciatus recorded the highest distribution of vectors with 56.6% and Culex pipens 43.4% (P > 0.05). Idi aba community recorded the highest distribution of mosquito vectors with 42.9% (n=322) and Culex quinqueaciatus was more abundantly distributed with 183 mosquitoes. Aro community recorded 32% (n=240) of captured mosquitoes with Culex quinquefaciatus having a higher level of abundance and lastly Kemta with a distribution of 25.1% (n=189). CONCLUSION Results from this study show that potential vectors of WNV abound within Abeokuta, putting residents at high risk of West Nile infection. We advocate for introduction of routine testing of WNV in Abeokuta and Nigeria.
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Johansson MA, Vasconcelos PFC, Staples JE. The whole iceberg: estimating the incidence of yellow fever virus infection from the number of severe cases. Trans R Soc Trop Med Hyg 2014; 108:482-7. [PMID: 24980556 DOI: 10.1093/trstmh/tru092] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Like many infectious agents, yellow fever (YF) virus only causes disease in a proportion of individuals it infects and severe illness only represents the tip of the iceberg relative to the total number of infections, the more critical factor for virus transmission. METHODS We compiled data on asymptomatic infections, mild disease, severe disease (fever with jaundice or hemorrhagic symptoms) and fatalities from 11 studies in Africa and South America between 1969 and 2011. We used a Bayesian model to estimate the probability of each infection outcome. RESULTS For YF virus infections, the probability of being asymptomatic was 0.55 (95% credible interval [CI] 0.37-0.74), mild disease 0.33 (95% CI 0.13-0.52) and severe disease 0.12 (95% CI 0.05-0.26). The probability of death for people experiencing severe disease was 0.47 (95% CI 0.31-0.62). CONCLUSIONS In outbreak situations where only severe cases may initially be detected, we estimated that there may be between one and seventy infections that are either asymptomatic or cause mild disease for every severe case identified. As it is generally only the most severe cases that are recognized and reported, these estimates will help improve the understanding of the burden of disease and the estimation of the potential risk of spread during YF outbreaks.
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Affiliation(s)
- Michael A Johansson
- Division of Vector-Borne Diseases, Centers for Disease Control & Prevention, Fort Collins, Colorado, USA
| | - Pedro F C Vasconcelos
- Instituto Evandro Chagas, Department of Arbovirology and Hemorrhagic Fevers, Ministry of Health, Ananindeua, Pará State, Brazil
| | - J Erin Staples
- Division of Vector-Borne Diseases, Centers for Disease Control & Prevention, Fort Collins, Colorado, USA
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Staples JE, Diallo M, Janusz KB, Manengu C, Lewis RF, Perea W, Yactayo S, Sall AA. Yellow fever risk assessment in the Central African Republic. Trans R Soc Trop Med Hyg 2014; 108:608-15. [PMID: 24947520 DOI: 10.1093/trstmh/tru086] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Starting in 2008, the Central African Republic (CAR) experienced an unprecedented number of reported yellow fever (YF) cases. A risk assessment of YF virus (YFV) activity was conducted to estimate potential disease risk and vaccine needs. METHODS A multistage cluster sampling design was used to sample humans, non-human primates, and mosquitoes in distinct ecologic zones. Humans and non-human primates were tested for YFV-specific antibodies; mosquitoes were tested for YFV RNA. RESULTS Overall, 13.3% (125/938) of humans were found to have naturally-acquired YFV antibodies. Antibody levels were higher in zones in the southern and south central regions of CAR. All sampled non-human primates (n=56) were known YFV reservoirs; one tested positive for YFV antibodies. Several known YF vectors were identified including Aedes africanus, Ae. aegypti, Ae. luteocephalus, and Ae. simpsoni. Several more urban locations were found to have elevated Breateau and Container indices for Ae. aegypti. CONCLUSIONS A country-wide assessment of YF risk found YFV to be endemic in CAR. The potential for future YF cases and outbreaks, however, varied by ecologic zone. Improved vaccination coverage through mass campaign and childhood immunization was recommended to mitigate the YF risk.
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Affiliation(s)
- J Erin Staples
- Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | | | - Kristen B Janusz
- Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | - Casimir Manengu
- World Health Organization, 1416 Bangui, Central African Republic
| | | | - William Perea
- World Health Organization, 1211 Geneva 27, Switzerland
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Garske T, Van Kerkhove MD, Yactayo S, Ronveaux O, Lewis RF, Staples JE, Perea W, Ferguson NM. Yellow Fever in Africa: estimating the burden of disease and impact of mass vaccination from outbreak and serological data. PLoS Med 2014; 11:e1001638. [PMID: 24800812 PMCID: PMC4011853 DOI: 10.1371/journal.pmed.1001638] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 03/27/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Yellow fever is a vector-borne disease affecting humans and non-human primates in tropical areas of Africa and South America. While eradication is not feasible due to the wildlife reservoir, large scale vaccination activities in Africa during the 1940s to 1960s reduced yellow fever incidence for several decades. However, after a period of low vaccination coverage, yellow fever has resurged in the continent. Since 2006 there has been substantial funding for large preventive mass vaccination campaigns in the most affected countries in Africa to curb the rising burden of disease and control future outbreaks. Contemporary estimates of the yellow fever disease burden are lacking, and the present study aimed to update the previous estimates on the basis of more recent yellow fever occurrence data and improved estimation methods. METHODS AND FINDINGS Generalised linear regression models were fitted to a dataset of the locations of yellow fever outbreaks within the last 25 years to estimate the probability of outbreak reports across the endemic zone. Environmental variables and indicators for the surveillance quality in the affected countries were used as covariates. By comparing probabilities of outbreak reports estimated in the regression with the force of infection estimated for a limited set of locations for which serological surveys were available, the detection probability per case and the force of infection were estimated across the endemic zone. The yellow fever burden in Africa was estimated for the year 2013 as 130,000 (95% CI 51,000-380,000) cases with fever and jaundice or haemorrhage including 78,000 (95% CI 19,000-180,000) deaths, taking into account the current level of vaccination coverage. The impact of the recent mass vaccination campaigns was assessed by evaluating the difference between the estimates obtained for the current vaccination coverage and for a hypothetical scenario excluding these vaccination campaigns. Vaccination campaigns were estimated to have reduced the number of cases and deaths by 27% (95% CI 22%-31%) across the region, achieving up to an 82% reduction in countries targeted by these campaigns. A limitation of our study is the high level of uncertainty in our estimates arising from the sparseness of data available from both surveillance and serological surveys. CONCLUSIONS With the estimation method presented here, spatial estimates of transmission intensity can be combined with vaccination coverage levels to evaluate the impact of past or proposed vaccination campaigns, thereby helping to allocate resources efficiently for yellow fever control. This method has been used by the Global Alliance for Vaccines and Immunization (GAVI Alliance) to estimate the potential impact of future vaccination campaigns.
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Affiliation(s)
- Tini Garske
- MRC Centre for Outbreak Analysis, Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | - Maria D. Van Kerkhove
- MRC Centre for Outbreak Analysis, Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | | | - Olivier Ronveaux
- Immunization and Vaccine Development, World Health Organization, Ouagadougou, Burkina Faso
| | | | - J. Erin Staples
- Arboviral Disease Branch, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | | | - Neil M. Ferguson
- MRC Centre for Outbreak Analysis, Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
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Brown JE, Evans BR, Zheng W, Obas V, Barrera-Martinez L, Egizi A, Zhao H, Caccone A, Powell JR. Human impacts have shaped historical and recent evolution in Aedes aegypti, the dengue and yellow fever mosquito. Evolution 2014; 68:514-25. [PMID: 24111703 PMCID: PMC3946797 DOI: 10.1111/evo.12281] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 09/20/2013] [Indexed: 01/18/2023]
Abstract
Although anthropogenic impacts are often considered harmful to species, human modifications to the landscape can actually create novel niches to which other species can adapt. These "domestication" processes are especially important in the context of arthropod disease vectors, where ecological overlap of vector and human populations may lead to epidemics. Here, we present results of a global genetic study of one such species, the dengue and yellow fever mosquito, Aedes aegypti, whose evolutionary history and current distribution have been profoundly shaped by humans. We used DNA sequences of four nuclear genes and 1504 single nucleotide polymorphism (SNP) markers developed with restriction-site associated DNA (RAD) sequencing to test the hypothesis that Ae. aegypti originated in Africa, where a domestic form arose and spread throughout the tropical and subtropical world with human trade and movement. Results confirmed African ancestry of the species, and supported a single subspeciation event leading to the pantropical domestic form. In addition, genetic data strongly supported the hypothesis that human trade routes first moved domestic Ae. aegypti out of Africa into the New World, followed by a later invasion from the New World into Southeast Asia and the Pacific. These patterns of domestication and invasion are relevant to many species worldwide, as anthropogenic forces increasingly impact evolutionary processes.
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Affiliation(s)
- Julia E Brown
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut.
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Barnett ED, Wilder-Smith A, Wilson ME. Yellow fever vaccines and international travelers. Expert Rev Vaccines 2014; 7:579-87. [DOI: 10.1586/14760584.7.5.579] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Turell MJ, Britch SC, Aldridge RL, Kline DL, Boohene C, Linthicum KJ. Potential for mosquitoes (Diptera: Culicidae) from Florida to transmit Rift Valley fever virus. JOURNAL OF MEDICAL ENTOMOLOGY 2013; 50:1111-1117. [PMID: 24180117 DOI: 10.1603/me13049] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We evaluated Aedes atlanticus Dyar and Knab, Aedes infirmatus Dyar and Knab, Aedes vexans (Meigen), Anopheles crucians Wiedemann, Coquillettidia perturbans (Walker), Culex nigripalpus Theobald, Mansonia dyari Belkin, Heinemann, and Page, and Psorophora ferox (Von Humboldt) from Florida to determine which of these species should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America. Female mosquitoes that had fed on adult hamsters inoculated with RVFV were incubated for 7-21 d at 26 degrees C, then allowed to refeed on susceptible hamsters, and tested to determine infection, dissemination, and transmission rates. We also inoculated mosquitoes intrathoracically, held them for 7 d, and then allowed them to feed on a susceptible hamster to check for a salivary gland barrier. When exposed to hamsters with viremias > or = 10(7.6) plaque-forming units per milliliter of blood, at least some individuals in each of the species tested became infected; however, Cx. nigripalpus, An. crucians, and Ae. infirmatus were essentially incompetent vectors in the laboratory because of either a midgut escape or salivary gland barrier. Each of the other species should be considered as potential vectors and would need to be controlled if RVFV were introduced into an area where they were found. Additional studies need to be conducted with other geographic populations of these species and to determine how environmental factors affect transmission.
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Affiliation(s)
- Michael J Turell
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, MD 21702-5011, USA.
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Woodson SE, Freiberg AN, Holbrook MR. Coagulation factors, fibrinogen and plasminogen activator inhibitor-1, are differentially regulated by yellow fever virus infection of hepatocytes. Virus Res 2013; 175:155-9. [PMID: 23639427 DOI: 10.1016/j.virusres.2013.04.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/17/2013] [Accepted: 04/22/2013] [Indexed: 10/26/2022]
Abstract
Yellow fever virus (YFV) infection poses a great risk to un-vaccinated individuals living or traveling in the endemic regions of Africa and South America. It is estimated that approximately 30,000 people die each year of this disease. The liver is the main target of YFV, where as many as 80% of the hepatocytes may become involved in the infection. The overwhelming infection of the liver is associated with the observed hemorrhagic disease manifestations such as petechiae, ecchymoses, and hematemesis which are all thought to be linked with the observed coagulation abnormalities that include prolonged clotting times, reduction in clotting factors, fibrin-split products (D-dimers) and elevated prothrombin times. Many factors involved in the coagulation pathway are produced by hepatocytes, such as fibrinogen (FBG) and plasminogen activator inhibitor-1 (PAI-1). Both of these proteins have been indicated in another flavivirus related disease, dengue, as having roles related to the bleeding abnormalities observed and overall outcome of infection. In this study we wanted to determine if FBG and PAI-1 expression levels by human hepatocytes was disrupted or altered by infection with either wild-type Asibi or vaccine strain17-D YFVs. Our findings indicate that YFV infection does affect the transcriptional and translational expression of FBG and PAI-1 in human hepatocytes and that these results are further affected by IL-6 during early stages of infection. These results may lead to further understanding of the molecular mechanism associated with bleeding abnormalities observed during late stage YFV infection.
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Affiliation(s)
- Sara E Woodson
- Department of Pathology and Institute for Human Infection and Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77550, USA
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Diallo D, Diagne CT, Hanley KA, Sall AA, Buenemann M, Ba Y, Dia I, Weaver SC, Diallo M. Larval ecology of mosquitoes in sylvatic arbovirus foci in southeastern Senegal. Parasit Vectors 2012; 5:286. [PMID: 23216815 PMCID: PMC3543325 DOI: 10.1186/1756-3305-5-286] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 12/03/2012] [Indexed: 11/18/2022] Open
Abstract
Background Although adult mosquito vectors of sylvatic arbovirus [yellow fever (YFV), dengue-2 (DENV-2) and chikungunya (CHIKV)] have been studied for the past 40 years in southeastern Senegal, data are still lacking on the ecology of larval mosquitoes in this area. In this study, we investigated the larval habitats of mosquitoes and characterized their seasonal and spatial dynamics in arbovirus foci. Methods We searched for wet microhabitats, classified in 9 categories, in five land cover classes (agriculture, forest, savannah, barren and village) from June, 2010 to January, 2011. Mosquito immatures were sampled monthly in up to 30 microhabitats of each category per land cover and bred until adult stage for determination. Results No wet microhabitats were found in the agricultural sites; in the remaining land covers immature stages of 35 mosquito species in 7 genera were sampled from 9 microhabitats (tree holes, fresh fruit husks, decaying fruit husks, puddles, bamboo holes, discarded containers, tires, rock holes and storage containers). The most abundant species was Aedes aegypti formosus, representing 30.2% of the collections, followed by 12 species, representing each more than 1% of the total, among them the arbovirus vectors Ae. vittatus (7.9%), Ae. luteocephalus (5.7%), Ae. taylori (5.0%), and Ae. furcifer (1.3%). Aedes aegypti, Cx. nebulosus, Cx. perfuscus, Cx. tritaeniorhynchus, Er. chrysogster and Ae. vittatus were the only common species collected from all land covers. Aedes furcifer and Ae. taylori were collected in fresh fruit husks and tree holes. Species richness and dominance varied significantly in land covers and microhabitats. Positive associations were found mainly between Ae. furcifer, Ae. taylori and Ae. luteocephalus. A high proportion of potential enzootic vectors that are not anthropophilic were found in the larval mosquito fauna. Conclusions In southeastern Senegal, Ae. furcifer and Ae. taylori larvae showed a more limited distribution among both land cover and microhabitat types than the other common species. Uniquely among vector species, Ae. aegypti formosus larvae occurred at the highest frequency in villages. Finally, a high proportion of the potential non-anthropophilic vectors were represented in the larval mosquito fauna, suggesting the existence of unidentified sylvatic arbovirus cycles in southeastern Senegal.
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Affiliation(s)
- Diawo Diallo
- Unité d'entomologie médicale, Institut Pasteur de Dakar, Dakar, Sénégal.
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Monath TP. Review of the risks and benefits of yellow fever vaccination including some new analyses. Expert Rev Vaccines 2012; 11:427-448. [DOI: 10.1586/erv.12.6] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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Brown JE, McBride CS, Johnson P, Ritchie S, Paupy C, Bossin H, Lutomiah J, Fernandez-Salas I, Ponlawat A, Cornel AJ, Black WC, Gorrochotegui-Escalante N, Urdaneta-Marquez L, Sylla M, Slotman M, Murray KO, Walker C, Powell JR. Worldwide patterns of genetic differentiation imply multiple 'domestications' of Aedes aegypti, a major vector of human diseases. Proc Biol Sci 2011; 278:2446-54. [PMID: 21227970 DOI: 10.1098/rspb.2010.2469] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Understanding the processes by which species colonize and adapt to human habitats is particularly important in the case of disease-vectoring arthropods. The mosquito species Aedes aegypti, a major vector of dengue and yellow fever viruses, probably originated as a wild, zoophilic species in sub-Saharan Africa, where some populations still breed in tree holes in forested habitats. Many populations of the species, however, have evolved to thrive in human habitats and to bite humans. This includes some populations within Africa as well as almost all those outside Africa. It is not clear whether all domestic populations are genetically related and represent a single 'domestication' event, or whether association with human habitats has developed multiple times independently within the species. To test the hypotheses above, we screened 24 worldwide population samples of Ae. aegypti at 12 polymorphic microsatellite loci. We identified two distinct genetic clusters: one included all domestic populations outside of Africa and the other included both domestic and forest populations within Africa. This suggests that human association in Africa occurred independently from that in domestic populations across the rest of the world. Additionally, measures of genetic diversity support Ae. aegypti in Africa as the ancestral form of the species. Individuals from domestic populations outside Africa can reliably be assigned back to their population of origin, which will help determine the origins of new introductions of Ae. aegypti.
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Affiliation(s)
- Julia E Brown
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06520, USA.
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Mirzaian E, Durham MJ, Hess K, Goad JA. Mosquito-Borne Illnesses in Travelers: A Review of Risk and Prevention. Pharmacotherapy 2010; 30:1031-43. [DOI: 10.1592/phco.30.10.1031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Yellow fever (YF) is a viral disease, endemic to tropical regions of Africa and the Americas, which principally affects humans and nonhuman primates and is transmitted via the bite of infected mosquitoes. Yellow fever virus (YFV) can cause devastating epidemics of potentially fatal, hemorrhagic disease. Despite mass vaccination campaigns to prevent and control these outbreaks, the risk of major YF epidemics, especially in densely populated, poor urban settings, both in Africa and South America, has greatly increased. Consequently, YF is considered an emerging, or reemerging disease of considerable importance. This article comprehensively reviews the history, microbiology, epidemiology, clinical presentation, diagnosis, and treatment of YFV, as well as the vaccines produced to combat YF.
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Affiliation(s)
- Christina L Gardner
- Center for Vaccine Research, Department of Microbiology and Molecular Genetics, University of Pittsburgh, PA 15261, USA
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Farnon EC, Gould LH, Griffith KS, Osman MS, Kholy AE, Brair ME, Panella AJ, Kosoy O, Laven JJ, Godsey MS, Perea W, Hayes EB. Household-based sero-epidemiologic survey after a yellow fever epidemic, Sudan, 2005. Am J Trop Med Hyg 2010; 82:1146-52. [PMID: 20519615 DOI: 10.4269/ajtmh.2010.09-0105] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
From September through early December 2005, an outbreak of yellow fever (YF) occurred in South Kordofan, Sudan, resulting in a mass YF vaccination campaign. In late December 2005, we conducted a serosurvey to assess YF vaccine coverage and to better define the epidemiology of the outbreak in an index village. Of 552 persons enrolled, 95% reported recent YF vaccination, and 25% reported febrile illness during the outbreak period: 13% reported YF-like illness, 4% reported severe YF-like illness, and 12% reported chikungunya-like illness. Of 87 persons who provided blood samples, all had positive YF serologic results, including three who had never been vaccinated. There was also serologic evidence of recent or prior chikungunya virus, dengue virus, West Nile virus, and Sindbis virus infections. These results indicate that YF virus and chikungunya virus contributed to the outbreak. The high prevalence of YF antibody among vaccinees indicates that vaccination was effectively implemented in this remotely located population.
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Affiliation(s)
- Eileen C Farnon
- Division of Vector-Borne Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
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Williams D, Gutiérrez JM, Harrison R, Warrell DA, White J, Winkel KD, Gopalakrishnakone P. The Global Snake Bite Initiative: an antidote for snake bite. Lancet 2010; 375:89-91. [PMID: 20109867 DOI: 10.1016/s0140-6736(09)61159-4] [Citation(s) in RCA: 221] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David Williams
- Australian Venom Research Unit, Department of Pharmacology, University of Melbourne, Parkville, VIC, Australia.
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Abstract
The past 30 years has witnessed a dramatic re-emergence of epidemic vector-borne diseases throughout much of the world. Factors contributing to this are many, but the principal drivers have been complacency and de-emphasis of infectious diseases in pubic health policy, increased population growth, uncontrolled urbanization without concomitant attention to water and waste management, increased globalization and the ease with which modern air transport can quickly spread pathogens and their vectors. The re-emergence of parasitic, bacterial and viral vector-borne pathogens is described. This re-emergence increases the current and future need for preventative measures to contain disease outbreaks and for international cooperation and collaboration to constantly monitor the outbreak of these debilitating and deadly diseases.
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Affiliation(s)
- Peter W. Atkinson
- Dept. Entomology, University of California, Riverside, Inst. Integrative Genome Biology & Center for Disease Vector Control, Riverside, CA 92521 USA
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Bernhardt SA, Blair C, Sylla M, Bosio C, Black WC. Evidence of multiple chromosomal inversions in Aedes aegypti formosus from Senegal. INSECT MOLECULAR BIOLOGY 2009; 18:557-569. [PMID: 19754736 DOI: 10.1111/j.1365-2583.2009.00895.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Chromosomal inversions are prevalent in mosquito species but polytene chromosomes are difficult to prepare and visualize in members of the tribe Aedinii and thus there exists only indirect evidence of inversions. We constructed an F(1) intercross family using a P(1) female from a laboratory strain of Aedes aegypti aegypti (Aaa) and a P(1) male Aedes aegypti formosus (Aaf) from a strain collected from south-eastern Senegal. Recombination rates in the F(2) offspring were severely reduced and genotype ratios suggested a deleterious recessive allele on chromosome 3. The F(2) linkage map was incongruent in most respects with the established map for Aaa. Furthermore, no increased recombination was detected in F(5) offspring. Recombination rates and gene order were consistent with the presence in Aaf of at least four large inversions on chromosome 1, a single small inversion on chromosome 2 and three inversions on chromosome 3.
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Affiliation(s)
- S A Bernhardt
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA
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Sylla M, Bosio C, Urdaneta-Marquez L, Ndiaye M, Black WC. Gene flow, subspecies composition, and dengue virus-2 susceptibility among Aedes aegypti collections in Senegal. PLoS Negl Trop Dis 2009; 3:e408. [PMID: 19365540 PMCID: PMC2663788 DOI: 10.1371/journal.pntd.0000408] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Accepted: 03/11/2009] [Indexed: 11/18/2022] Open
Abstract
Background Aedes aegypti, the “yellow fever mosquito”, is the primary vector to humans of the four serotypes of dengue viruses (DENV1-4) and yellow fever virus (YFV) and is a known vector of Chikungunya virus. There are two recognized subspecies of Ae. aegypti sensu latu (s.l.): the presumed ancestral form, Ae. aegypti formosus (Aaf), a primarily sylvan mosquito in sub-Saharan Africa, and Ae. aegypti aegypti (Aaa), found globally in tropical and subtropical regions typically in association with humans. The designation of Ae. aegypti s.l. subspecies arose from observations made in East Africa in the late 1950s that the frequency of pale “forms” of Ae. aegypti was higher in populations in and around human dwellings than in those of the nearby bush. But few studies have been made of Ae. aegypti s.l. in West Africa. To address this deficiency we have been studying the population genetics, subspecies composition and vector competence for DENV-2 of Ae. aegypti s.l. in Senegal. Methods and Findings A population genetic analysis of gene flow was conducted among 1,040 Aedes aegypti s.l. from 19 collections distributed across the five phytogeographic regions of Senegal. Adults lacking pale scales on their first abdominal tergite were classified as Aedes aegypti formosus (Aaf) following the original description of the subspecies and the remainder were classified as Aedes aegypti aegypti (Aaa). There was a clear northwest–southeast cline in the abundance of Aaa and Aaf. Collections from the northern Sahelian region contained only Aaa while southern Forest gallery collections contained only Aaf. The two subspecies occurred in sympatry in four collections north of the Gambia in the central Savannah region and Aaa was a minor component of two collections from the Forest gallery area. Mosquitoes from 11 collections were orally challenged with DENV-2 virus. In agreement with the early literature, Aaf had significantly lower vector competence than Aaa. Among pure Aaa collections, the disseminated infection rate (DIR) was 73.9% with a midgut infection barrier (MIB) rate of 6.8%, and a midgut escape barrier (MEB) rate of 19.3%, while among pure Aaf collections, DIR = 34.2%, MIB rate = 7.4%, and MEB rate = 58.4%. Allele and genotype frequencies were analyzed at 11 nuclear single nucleotide polymorphism (SNP) loci using allele specific PCR and melting curve analysis. In agreement with a published isozyme gene flow study in Senegal, only a small and statistically insignificant percentage of the variance in allele frequencies was associated with subspecies. Conclusions These results add to our understanding of the global phylogeny of Aedes aegypti s.l., suggesting that West African Aaa and Aaf are monophyletic and that Aaa evolved in West Africa from an Aaf ancestor. We conducted a population genetic study with 1,040 Aedes aegypti sensu latu (s.l.) collected from 19 sites distributed across the five phytogeographic regions of Senegal. Adult mosquitoes without pale scales on their first abdominal tergite were classified as Aedes aegypti formosus (Aaf) and those having pale scales as Aedes aegypti aegypti (Aaa). We found the two forms distributed along a northwest–southeast cline. Northern Sahelian collections contained only Aaa while the southern Forest gallery collections consisted of only Aaf. The two subspecies were sympatric in four collections north of The Gambia. Aaa was a minor component of two collections from the Forest gallery area. Eleven of these collections were fed a dengue-2 virus–infected bloodmeal. Consistent with the early literature, Aaf had lower vector competence than Aaa. In agreement with a recently published isozyme gene flow study in Senegal, analyzes of allele frequencies indicated only a small, nonsignificant percentage of the variance associated with subspecies. These results improve our understanding of the global phylogeny of Aedes aegypti s.l., suggesting that West African Aaa and Aaf are monophyletic and that Aaf, the black “sylvan” species, is the ancestor of Aaa, the lighter “domestic” species in West Africa.
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Affiliation(s)
- Massamba Sylla
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Christopher Bosio
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Ludmel Urdaneta-Marquez
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mady Ndiaye
- Departement de Biologie Animale, Faculte des Sciences et Techniques, Universite Cheikh Anta DIOP de Dakar, Dakar, Senegal
| | - William C. Black
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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Abstract
Despite the availability of a safe and efficacious vaccine, yellow fever (YF) remains a disease of significant public health importance, with an estimated 200,000 cases and 30,000 deaths annually. The disease is endemic in tropical regions of Africa and South America; nearly 90% of YF cases and deaths occur in Africa. It is a significant hazard to unvaccinated travelers to these endemic areas. Virus transmission occurs between humans, mosquitoes, and monkeys. The mosquito, the true reservoir of YF, is infected throughout its life, and can transmit the virus transovarially through infected eggs. Man and monkeys, on the other hand, play the role of temporary amplifiers of the virus available for mosquito infection. Recent increases in the density and distribution of the urban mosquito vector, Aedes aegypti, as well as the rise in air travel increase the risk of introduction and spread of yellow fever to North and Central America, the Caribbean, the Middle East, Asia, Australia, and Oceania. It is an acute infectious disease characterized by sudden onset with a two-phase development, separated by a short period of remission. The clinical spectrum of yellow fever varies from very mild, nonspecific, febrile illness to a fulminating, sometimes fatal disease with pathognomic features. In severe cases, jaundice, bleeding diathesis, with hepatorenal involvement are common. The case fatality rate of severe yellow fever is 50% or higher. The pathogenesis and pathophysiology of the disease are poorly understood and have not been the subject of modern clinical research. There is no specific treatment for YF, making the management of YF patients extremely problematic. YF is a zoonotic disease that cannot be eradicated, therefore instituting preventive vaccination through routine childhood vaccination in endemic countries, can significantly reduce the burden of the disease. The distinctive properties of lifelong immunity after a single dose of yellow fever vaccination are the basis of the new applications of yellow fever 17D virus as a vector for foreign genes, "the chimeric vaccine,' and the promise of developing new vaccines against other viruses, and possibly against cancers.
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Affiliation(s)
- Oyewale Tomori
- World Health Organization-Africa Region, Harare, Zimbabwe.
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Barrett ADT, Monath TP, Barban V, Niedrig M, Teuwen DE. 17D yellow fever vaccines: New insights. Vaccine 2007; 25:2758-65. [PMID: 17368349 DOI: 10.1016/j.vaccine.2006.12.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 11/30/2006] [Accepted: 12/05/2006] [Indexed: 11/17/2022]
Abstract
Yellow fever (YF) is a major health problem in endemic regions of Africa and South America. It also poses a serious health risk to travellers to areas with endemic disease. Currently, there is no effective drug treatment for YF; however, 17D YF vaccines have demonstrated high rates of effectiveness and good safety profiles. This workshop was organized to review key data and issues about YF disease and currently available 17D YF vaccines. Starting with an overview of the current disease epidemiology in Africa and South America and a review of the safety data of 17D YF vaccines, data were then presented demonstrating the genetic stability of multiple production lots of a 17D YF vaccine, the immunological responses of healthy subjects post-vaccination and the long-term immunogenicity of 17D YF vaccines. Finally, the findings of the molecular characterization of 17D YF virus sub-strains recovered from rare, fatal cases of post-vaccination serious adverse events were presented. There was unanimous agreement that current 17D YF vaccines have a highly favourable benefit-risk profile when used in persons at risk of exposure to the YF virus, and that appropriate use of 17D YF vaccines will minimize the occurrence of serious adverse events post-vaccination.
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Affiliation(s)
- Alan D T Barrett
- Sealy Centre for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555 0609, USA
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40
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Abstract
Yellow fever virus (YFV) is the prototype member of the genus Flavivirus, a group of viruses that are transmitted between vertebrates by arthropod vectors. The virus is found in tropical regions of Africa and South America and is transmitted to primates by mosquitoes: Aedes spp. in Africa and Haemagogus and Sabethes spp. in South America. Despite the availability of an effective vaccine, yellow fever (YF) is considered a reemerging disease owing to its increased incidence in the past 25 years. Molecular epidemiologic data suggest there are seven genotypes of YFV that are geographically separated, and outbreaks of disease are more associated with particular genotypes. In addition, the risk of urban YF, owing to transmission of the virus by Aedes aegypti, is increasing in Africa, as is the potential of urban YF returning to South America. Both present serious potential public health problems to large population centers.
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Affiliation(s)
- Alan D T Barrett
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA.
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Codeço CT, Luz PM, Struchiner CJ. Risk assessment of yellow fever urbanization in Rio de Janeiro, Brazil. Trans R Soc Trop Med Hyg 2005; 98:702-10. [PMID: 15485700 DOI: 10.1016/j.trstmh.2003.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2003] [Revised: 12/11/2003] [Accepted: 12/16/2003] [Indexed: 11/23/2022] Open
Abstract
Yellow fever (YF), an arthropod-borne viral disease, occurs in regions of tropical America and Africa. Sylvatic YF is endemic in the north and west of Brazil. Urban YF, on the other hand, has not been reported in the country since 1942. However, the widespread presence of the YF urban vector in Brazil has lead to concern about the potential re-emergence of YF in urban centres. Here, we assess the risk of YF emergence in the city of Rio de Janeiro, Brazil, by estimating the probability of infected individuals arriving from YF-endemic areas, and the probability of infective individuals triggering an epidemic. We found that the risk of urban YF emergence may reach values as high as 29% during the epizootic periods but the precision of the estimate is low.
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Affiliation(s)
- C T Codeço
- Programa de Computação Científica, Fundação Oswaldo Cruz, Avenida Brasil, 4365, Antiga Residencia Oficial, Rio de Janeiro, RJ 21045-900, Brazil.
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42
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Abstract
The dengue, West Nile, Japanese encephalitis and yellow fever viruses are important mosquito-borne viruses whose epidemiology is shifting in response to changing societal factors, such as increasing commerce, urbanization of rural areas, and population growth. All four viruses are expanding geographically, as exemplified by the emergence of West Nile virus in the Americas and Japanese encephalitis virus in Australasia. The large, recent global outbreaks of severe neurological disease caused by West Nile virus, the increasing frequency of dengue hemorrhagic fever outbreaks in the Americas, and the emergence of yellow fever virus vaccination-associated viscerotropic disease, are new clinical epidemiologic trends. These worrisome epidemiologic trends will probably continue in coming decades, as a reversal of their societal and biological drivers is not in sight. Nevertheless, the substantial reductions in Japanese encephalitis virus incidence resulting from vaccination programs and economic development in some Asian countries provide some encouragement within this overall guarded outlook.
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Affiliation(s)
- Lyle R Petersen
- Division of Vector-borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA
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43
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Marfin AA, Eidex RSB, Kozarsky PE, Cetron MS. Yellow fever and Japanese encephalitis vaccines: indications and complications. Infect Dis Clin North Am 2005; 19:151-68, ix. [PMID: 15701552 DOI: 10.1016/j.idc.2004.11.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Appropriate administration of yellow fever or Japanese encephalitis vaccines to travelers requires an assessment of the traveler's risk for infection with these vector-borne flaviviruses during their travels and the presence of risk factors for adverse events following immunization. Japanese encephalitis and yellow fever vaccines have been more frequently associated with serious adverse events following immunization since the early 1980s and the late 1990s, respectively. This article describes the adverse events, the magnitude of their risk, and associated risk factors.
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Affiliation(s)
- Anthony A Marfin
- Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA.
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Gubler DJ. The changing epidemiology of yellow fever and dengue, 1900 to 2003: full circle? Comp Immunol Microbiol Infect Dis 2004; 27:319-30. [PMID: 15225982 DOI: 10.1016/j.cimid.2004.03.013] [Citation(s) in RCA: 256] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Yellow fever and dengue are old diseases, having caused major epidemics in centuries past. Both were effectively controlled in the mid 1900s, yellow fever in Francophone Africa by vaccination and yellow fever and dengue in the Americas by effective control of the principal urban vector of both viruses, Aedes aegypti. In the last 25 years of the 20th century, however, there was a resurgence of yellow fever in Africa, and of dengue worldwide. The factors responsible for this resurgence are discussed, as are current options for prevention and control.
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Affiliation(s)
- D J Gubler
- Asia-Pacific Institute of Tropical Medicine and Infectious Diseases, John A. Burns School of Medicine, University of Hawaii at Manoa, 3675 Kilauea Avenue, Leahi Hospital, Honolulu, HI 96816, USA.
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45
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Abstract
It will be apparent to the reader that there is much to learn about the pathogenesis of YF. The role of specific genes and molecular determinants of neurotropism and viscerotropism has been defined only partially. The availability of infectious clones and a small animal (hamster) model should allow dissection of virulence factors, which can then be tested in the more difficult monkey model. The marked differences between wild-type YF strains should be evaluated by evaluating the relationships between virulence and genome sequence. The role of cytokine dysregulation and endothelial injury in YF will be elucidated as access to patients and of patients to more sophisticated medical care improves. The number of cases of YF in unvaccinated travelers hospitalized after return from the tropics has unfortunately increased, but such cases afford unique opportunities to study the pathogenesis of renal failure, coagulopathy, vascular instability, and shock, as well as new treatment modalities. At the cellular level, there are also important opportunities for research on YF virus-cell receptor interactions, the control of apoptotic cell death, and the predilection for cells of the midzone of the liver lobule. The role of dendritic cells in the early stage of YF infection is deserving of study. Finally, the role of the immune response to infection, particularly cellular immunity, is poorly characterized, and the suggestion that immune clearance may aggravate the condition of the host during the period of intoxication should be evaluated in appropriate animal models.
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Affiliation(s)
- Thomas P Monath
- Acambis Inc. and Department of Microbiology and Immunology, Harvard School of Public Health, Cambridge, Massachusetts 02139, USA
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46
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Abstract
Yellow fever (YF) is still a major public heath problem, particularly in Africa, despite the availability of a very efficacious vaccine. The World Health Organization estimates that there are 200,000 cases of YF annually, including 30,000 deaths, of which over 90% occur in Africa. In the past 15 years, the number of YF cases has increased tremendously, with most of the YF activity in West Africa. This increase in YF activity is in part due to a breakdown in YF vaccination and mosquito control programs. Five genotypes of YF virus have been found in Africa, and each genotype circulates in a distinct geographical region. West Africa genotype I, found in Nigeria and surrounding areas, is associated with frequent epidemics, whereas the three genotypes in East and Central Africa are in regions where YF outbreaks are rare. Other factors, including genetic and behavioral variation among vector species, are also thought to play a role in the epidemiology of YF in Africa.
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Affiliation(s)
- John-Paul Mutebi
- Center for Tropical Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0609, USA
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47
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Jupp PG, Kemp A. Laboratory vector competence experiments with yellow fever virus and five South African mosquito species including Aedes aegypti. Trans R Soc Trop Med Hyg 2002; 96:493-8. [PMID: 12474475 DOI: 10.1016/s0035-9203(02)90417-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Three domestic and peridomestic mosquito species, selected because their prevalence, distribution and ecology favoured them as potential urban vectors of yellow fever (YF) in South Africa, were submitted to numerous tests for infectivity [measured as dose needed to infect 50% of the mosquitoes (MID50)], mainly with a Kenyan strain (BC7914) of the virus. Use of a Nigerian virus strain (TVP1617) did not significantly alter infectivity. After artificial infective blood meals with titres of 7.0-8.0 log10MID50/mL, head squash infection rates (HSIRs) determined by the indirect fluorescent antibody test were 0-4% (Eretmapodites quinquevittatus), 0-29% (Aedes simpsoni s. s.) and 0-21% (5 populations of Aedes aegypti). For some populations of Ae. aegypti tests were repeated with blood meals incorporating freshly prepared rather than frozen mouse brain but HSIRs did not increase. HSIRs did increase when a high infecting titre of 9.0 log10MID50/mL was used with the Richards Bay population (67-90%). It is concluded that these 3 mosquito species are potentially poor YF vectors but that Ae. simpsoni and Richards Bay Ae. aegypti are the most susceptible to the virus. However, the latter 2 species could support person-to-person transmission only if they were present at very high densities. This rarely occurs with Ae. simpsoni in South Africa but Ae. aegypti may occur at high densities although only in discrete foci. The feral Ae. furcifer and Ae. cordellieri had HSIRs of 29% and 3% respectively and Ae. furcifer 'transmitted' the virus in vitro at a transmission rate of 25%. This suggests that Ae. furcifer would be more important than Ae. cordellieri in transmission between monkeys in West Africa.
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Affiliation(s)
- Peter G Jupp
- Special Pathogens Unit, National Institute for Communicable Diseases, Department of Virology, University of the Witwatersrand, Private Bag X4, Sandringham, South Africa
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Black WC, Bennett KE, Gorrochótegui-Escalante N, Barillas-Mury CV, Fernández-Salas I, de Lourdes Muñoz M, Farfán-Alé JA, Olson KE, Beaty BJ. Flavivirus susceptibility in Aedes aegypti. Arch Med Res 2002; 33:379-88. [PMID: 12234528 DOI: 10.1016/s0188-4409(02)00373-9] [Citation(s) in RCA: 238] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Aedes aegypti is the primary vector of yellow fever (YF) and dengue fever (DF) flaviviruses worldwide. In this review we focus on past and present research on genetic components and environmental factors in Aedes aegypti that appear to control flavivirus transmission. We review genetic relationships among Ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. We describe current research into how genetic and environmental factors jointly affect distribution of vector competence in natural populations. Based on this information, we propose a population genetic model for vector competence and discuss our recent progress in testing this model. We end with a discussion of approaches being taken to identify the genes that may control flavivirus susceptibility in Ae. aegypti.
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Affiliation(s)
- William C Black
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
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49
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Abstract
Viral diseases transmitted by blood-feeding arthropods (arboviral diseases) are among the most important of the emerging infectious disease public health problems facing the world at the beginning of the third millennium. There are over 534 viruses listed in the arbovirus catalogue, approximately 134 of which have been shown to cause disease in humans. These are transmitted principally by mosquitoes and ticks. In the last two decades of the twentieth century, a few new arboviral diseases have been recognized. More important, however, is the dramatic resurgence and geographic spread of a number of old diseases that were once effectively controlled. Global demographic and societal changes, and modern transportation have provided the mechanisms for the viruses to break out of their natural ecology and become established in new geographic locations where susceptible arthropod vectors and hosts provide permissive conditions for them to cause major epidemics. West Nile virus is just the the latest example of this type of invasion by exotic viruses. This paper will provide an overview of the medically important arboviruses and discuss several in more detail as case studies to illustrate our tenuous position as we begin the twenty-first century.
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Affiliation(s)
- D J Gubler
- Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado 80522, USA.
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50
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Abstract
Global atmospheric temperatures are presently in a warming phase that began 250--300 years ago. Speculations on the potential impact of continued warming on human health often focus on mosquito-borne diseases. Elementary models suggest that higher global temperatures will enhance their transmission rates and extend their geographic ranges. However, the histories of three such diseases--malaria, yellow fever, and dengue--reveal that climate has rarely been the principal determinant of their prevalence or range; human activities and their impact on local ecology have generally been much more significant. It is therefore inappropriate to use climate-based models to predict future prevalence.
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Affiliation(s)
- P Reiter
- Dengue Branch, Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, San Juan, Puerto Rico 00920-3860.
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