1
|
De Clerck I. Outbreak of Rift Valley Fever Retinitis in Rwanda: Novel Imaging Findings and Response to Treatment with Corticosteroids. Ocul Immunol Inflamm 2024; 32:1374-1379. [PMID: 37585678 DOI: 10.1080/09273948.2023.2246549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 06/21/2023] [Accepted: 08/06/2023] [Indexed: 08/18/2023]
Abstract
PURPOSE To describe the clinical and epidemiological characteristics of the first epidemic of Rift Valley Fever retinitis in Rwanda and to report novel imaging findings and a possible role for corticosteroids. METHODS Retrospective analysis of all patients who presented with presumed Rift Valley Fever retinitis at the Rwanda Charity Eye Hospital over a period of 4 months in 2022. Multimodal images are reviewed including optical coherence tomography, fluorescein angiography, color, infrared, red-free, and autofluorescence photography. RESULTS The newly identified arciform hyporeflective pattern on infrared imaging was present in 100% of patients. Out of 9 patients treated with oral corticosteroids, 7 (78%) experienced a visual acuity increase of at least 0.2 during follow-up, in comparison to only 4 (28%) out of 14 of untreated patients. Out of four patients treated with a subtenon corticosteroid injection, only one (25%) reached this threshold. Post-hoc pairwise comparison with Bonferroni correction revealed a significant difference in average visual acuity improvement (p = 0.034) between patients receiving oral corticosteroids (0.35 ± 0.07) versus no treatment (0.11 ± 0.04). CONCLUSION The identified arciform hyporeflective pattern on infrared imaging appears to be characteristic of Rift Valley Fever retinitis and should be known to clinicians working in endemic regions. Compared to a historical cohort and to untreated patients in this non-randomized study, there appears to be a benefit of treatment with oral corticosteroids.
Collapse
Affiliation(s)
- Ivo De Clerck
- Department of Ophthalmology, University Hospitals Leuven, Leuven, Belgium
- Department of Ophthalmology, Military Hospital Queen Astrid, Brussels, Belgium
- Department of Ophthalmology, Rwanda Charity Eye Hospital, Kamonyi, Rwanda
| |
Collapse
|
2
|
Gahn MCB, Diouf G, Cissé N, Ciss M, Bordier M, Ndiaye M, Bakhoum MT, Djiba ML, Brown C, Faburay B, Fall AG, Lo MM. Large-Scale Serological Survey of Crimean-Congo Hemorrhagic Fever Virus and Rift Valley Fever Virus in Small Ruminants in Senegal. Pathogens 2024; 13:689. [PMID: 39204289 PMCID: PMC11356896 DOI: 10.3390/pathogens13080689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Revised: 07/27/2024] [Accepted: 07/30/2024] [Indexed: 09/03/2024] Open
Abstract
Crimean-Congo hemorrhagic fever (CCHF) and Rift Valley fever (RVF) are among the list of emerging zoonotic diseases that require special attention and priority. RVF is one of the six priority diseases selected by the Senegalese government. Repeated epidemic episodes and sporadic cases of CCHF and RVF in Senegal motivated this study, involving a national cross-sectional serological survey to assess the distribution of the two diseases in this country throughout the small ruminant population. A total of 2127 sera from small ruminants (goat and sheep) were collected in all regions of Senegal. The overall seroprevalence of CCHF and RVF was 14.1% (IC 95%: 12.5-15.5) and 4.4% (95% CI: 3.5-5.3), respectively. The regions of Saint-Louis (38.4%; 95% CI: 30.4-46.2), Kolda (28.3%; 95% CI: 20.9-35.7), Tambacounda (22.2%; 95% CI: 15.8-28.6) and Kédougou (20.9%; 95% CI: 14.4-27.4) were the most affected areas. The risk factors identified during this study show that the age, species and sex of the animals are key factors in determining exposure to these two viruses. This study confirms the active circulation of CCHF in Senegal and provides important and consistent data that can be used to improve the surveillance strategy of a two-in-one health approach to zoonoses.
Collapse
Affiliation(s)
- Marie Cicille Ba Gahn
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Gorgui Diouf
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Ndjibouyé Cissé
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Mamadou Ciss
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Marion Bordier
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
- Centre de Coopération Internationale en Recherche Agronomique pour le Developpement (CIRAD), UMR ASTRE, F-34398 Montpellier, France
| | - Mbengué Ndiaye
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Mame Thierno Bakhoum
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Mamadou Lamine Djiba
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Corrie Brown
- LifeStock International, 550 Fortson Rd., Athens, GA 30606, USA
| | - Bonto Faburay
- Foreign Animal Disease Diagnostic Laboratory, National Veterinary Services Laboratories, National Bio and Agro-Defense Facility, United States Department of Agriculture, Manhattan, KS 66505, USA
| | - Assane Gueye Fall
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| | - Modou Moustapha Lo
- Institut Sénégalais de Recherches Agricoles, Laboratoire National de l’Elevage et de Recherches Vétérinaires (ISRA-LNERV), Dakar-Hann BP 2057, Senegal
| |
Collapse
|
3
|
Sene O, Sagne SN, Bob NS, Mhamadi M, Dieng I, Gaye A, Ba H, Dia M, Faye ET, Diop SM, Sall Y, Diop B, Ndiaye M, Loucoubar C, Simon-Lorière E, Sakuntabhai A, Faye O, Sall AA, Diallo D, Dia N, Faye O, Diagne MM, Fall M, Ndione MHD, Barry MA, Fall G. Re-Emergence of Rift Valley Fever Virus Lineage H in Senegal in 2022: In Vitro Characterization and Impact on Its Global Emergence in West Africa. Viruses 2024; 16:1018. [PMID: 39066182 PMCID: PMC11281490 DOI: 10.3390/v16071018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/18/2024] [Accepted: 06/06/2024] [Indexed: 07/28/2024] Open
Abstract
Rift Valley fever (RVF) is a re-emerging vector-borne zoonosis with a high public health and veterinary impact. In West Africa, many lineages were previously detected, but since 2020, lineage H from South Africa has been the main cause of the outbreaks. In this study, clinical samples collected through national surveillance were screened for RVF virus (RVFV) acute infection by RT-PCR and IgM ELISA tests. Sequencing, genome mapping and in vitro phenotypic characterization in mammal cells were performed on RT-PCR positive samples in comparison with other epidemic lineages (G and C). Four RVFV human cases were detected in Senegal and the sequence analyses revealed that the strains belonged to lineage H. The in vitro kinetics and genome mapping showed different replication efficiency profiles for the tested RVFV lineages and non-conservative mutations, which were more common to lineage G or specific to lineage H. Our findings showed the re-emergence of lineage H in Senegal in 2022, its high viral replication efficiency in vitro and support the findings that genetic diversity affects viral replication. This study gives new insights into the biological properties of lineage H and calls for deeper studies to better assess its potential to cause a future threat in Senegal.
Collapse
Affiliation(s)
- Ousseynou Sene
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Samba Niang Sagne
- Epidemiology, Clinical Research & Data Science, Pasteur Institute, Dakar 12900, Senegal; (S.N.S.); (A.G.); (C.L.); (M.A.B.)
| | - Ndeye Sakha Bob
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | | | - Idrissa Dieng
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Aboubacry Gaye
- Epidemiology, Clinical Research & Data Science, Pasteur Institute, Dakar 12900, Senegal; (S.N.S.); (A.G.); (C.L.); (M.A.B.)
| | - Haoua Ba
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Moussa Dia
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Elisabeth Thérèse Faye
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Sokhna Mayemouna Diop
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Yoro Sall
- Ministry of Health, Dakar 10700, Senegal; (Y.S.); (B.D.); (M.N.)
| | - Boly Diop
- Ministry of Health, Dakar 10700, Senegal; (Y.S.); (B.D.); (M.N.)
| | - Mamadou Ndiaye
- Ministry of Health, Dakar 10700, Senegal; (Y.S.); (B.D.); (M.N.)
| | - Cheikh Loucoubar
- Epidemiology, Clinical Research & Data Science, Pasteur Institute, Dakar 12900, Senegal; (S.N.S.); (A.G.); (C.L.); (M.A.B.)
| | | | - Anavaj Sakuntabhai
- Functional Genetics of Infectious Disease Unit, Pasteur Institute, 75015 Paris, France;
- Centre National de la Recherche Scientifique (CNRS), UMR2000, Department of Global Health, 75015 Paris, France
- International Vaccine Design Center (vDesC), the Institute of Medical Science, University of Tokyo (IMSUT), Tokyo 108-8639, Japan
| | - Ousmane Faye
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Amadou Alpha Sall
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Diawo Diallo
- Zoology Department, Pasteur Institute, Dakar 12900, Senegal;
| | - Ndongo Dia
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Oumar Faye
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Moussa Moise Diagne
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Malick Fall
- Animal Biology Department, Faculty of Sciences and Techniques, Cheikh Anta Diop University, Dakar 10700, Senegal;
| | - Marie Henriette Dior Ndione
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| | - Mamadou Aliou Barry
- Epidemiology, Clinical Research & Data Science, Pasteur Institute, Dakar 12900, Senegal; (S.N.S.); (A.G.); (C.L.); (M.A.B.)
| | - Gamou Fall
- WHO Collaborating Centre for Arbovirus and Viral Hemorrhagic Fevers, Virology Department, Pasteur Institute, Dakar 12900, Senegal; (N.S.B.); (I.D.); (H.B.); (M.D.); (E.T.F.); (S.M.D.); (O.F.); (A.A.S.); (N.D.); (O.F.); (M.M.D.); (M.H.D.N.); (G.F.)
| |
Collapse
|
4
|
Chemison A, Ramstein G, Jones A, Morse A, Caminade C. Ability of a dynamical climate sensitive disease model to reproduce historical Rift Valley Fever outbreaks over Africa. Sci Rep 2024; 14:3904. [PMID: 38365824 PMCID: PMC10873308 DOI: 10.1038/s41598-024-53774-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 02/05/2024] [Indexed: 02/18/2024] Open
Abstract
Rift Valley Fever (RVF) is a zoonosis transmitted by Aedes and Culex mosquitoes, and is considered a priority pathogen by the WHO. RVF epidemics mostly occur in Africa and can decimate livestock herds, causing significant economic losses and posing health risks for humans. RVF transmission is associated with the occurrence of El Niño events that cause floods in eastern Africa and favour the emergence of mosquitoes in wetlands. Different risk models have been developed to forecast RVF transmission risk but very few studies have validated models at pan-African scale. This study aims to validate the skill of the Liverpool Rift Valley Fever model (LRVF) in reproducing RVF epidemics over Africa and to explore the relationship between simulated climatic suitability for RVF transmission and large-scale climate modes of variability such as the El Niño Southern Oscillation (ENSO) and the Dipole Mode Index (DMI). Our results show that the LRVF model correctly simulates RVF transmission hotspots and reproduces large epidemics that affected African countries. LRVF was able to correctly reproduce major RVF epidemics in Somalia, Kenya, Zambia and to a lesser extent for Mauritania and Senegal. The positive phases of ENSO and DMI are associated with an increased risk of RVF over the Horn of Africa, with important time lags. Following research activities should focus on the development of predictive modelling systems at different time scales.
Collapse
Affiliation(s)
- Alizée Chemison
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA, CNRS, UVSQ, 91190, Gif-sur-Yvette, France
| | - Gilles Ramstein
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA, CNRS, UVSQ, 91190, Gif-sur-Yvette, France
| | - Anne Jones
- IBM Research Laboratory, Daresbury, WA4 4AD, UK
| | - Andy Morse
- Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, L69 7ZT, UK
| | - Cyril Caminade
- Earth System Physics, Abdus Salam International Centre for Theoretical Physics, 34151, Trieste, Italy.
| |
Collapse
|
5
|
Tejiokem MC, Barry A, Ratovoson R, Yambiyo B, Hamidou Lazoumar R, Herrant M, Madaha E, Richard V. African countries from the Pasteur Network reexamine their syndromic sentinel surveillance system associated with household contact within the AFROSCREEN program. Front Public Health 2024; 11:1292435. [PMID: 38249384 PMCID: PMC10796548 DOI: 10.3389/fpubh.2023.1292435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/18/2023] [Indexed: 01/23/2024] Open
Abstract
Surveillance to better detect and respond to new pathogens remains a major challenge for global public health. The Pasteur Network recently held a brainstorming workshop located in Cameroon attended by Pasteur epidemiological teams from Niger, Central African Republic (CAR), Cameroon, Senegal, and Madagascar to discuss how the Pasteur Network in Africa could use the lessons of COVID-19 to set-up a pilot sentinel surveillance scheme given its expertise and involvement during the pandemic. The possibility of coupling sentinel syndromic and biological surveillance already implemented for influenza surveillance with the recent sequencing capacity put in place by the AFROSCREEN program prompted us to consider strengthening surveillance tools to target "Pathogen X" detection in Africa. The perspective project provided by the Pasteur Network teams and shared with other partners of the AFROSCREEN program will target strengthening of the diagnosis of severe acute respiratory infections (IRAS) and the surveillance of IRAS, the evaluation of the impact of SARS-CoV-2 on the epidemiology of IRAS, and the addition of the detection of new pathogens, called "Pathogen X," based on sequencing capacity and epidemiological criteria from One Health approaches.
Collapse
Affiliation(s)
| | | | - Rila Ratovoson
- Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Brice Yambiyo
- Institut Pasteur de Bangui, Bangui, Central African Republic
| | | | | | | | | |
Collapse
|
6
|
Mukhopadhyay K, Sengupta M, Misra SC, Majee K. Trends in emerging vector-borne viral infections and their outcome in children over two decades. Pediatr Res 2024; 95:464-479. [PMID: 37880334 DOI: 10.1038/s41390-023-02866-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/27/2023] [Accepted: 10/02/2023] [Indexed: 10/27/2023]
Abstract
This review utilizes quatitative methods and bibliometric data to analyse the trends of emerging and re-emerging vector-borne diseases, with a focus on their impact on pediatric population. To conduct this analysis, a systematic search of PubMed articles from the past two decades was performed, specifically looking at 26 different vector-borne viruses listed in WHO and CDC list of vector-borne viruses. The review found that diseases like Dengue, Zika, West Nile, and Chikungunya were frequently discussed in the literature. On the other hand, diseases such as Tick-borne encephalitis, Rift Valley fever, Venezuelan equine encephalitis, Sindbis fever, Venezuelan equine encephalitis, Ross River virus, and Eastern equine encephalitis showed an upward trend in publications, indicating potential resurgence. In addition to discussing trends and patterns, the review delves into the clinical manifestations and long-term effects of the top 10 viruses in children. It highlights various factors including deforestation, urbanization, global travel, and immunosuppression that contribute to disease emergence and resurgence. To effectively combat these vector-borne diseases, continuous surveillance is crucial. The review also emphasizes the importance of increased vaccination efforts and targeted research to address the health challenges they pose. IMPACT: This review employs quantitative analysis of publications to elucidate trends in emerging pediatric vector-borne viral diseases over two decades. Dengue, the most prevalent of these diseases, has spread to new regions. New strains of Japanese Encephalitis have caused outbreaks. Resurgence of Tick-borne Encephalitis, West Nile, and Yellow Fever due to vaccine hesitancy has also transpired. Continuous global surveillance, increased vaccination, and research into novel therapeutics are imperative to combat the substantial morbidity and mortality burden these diseases pose for children worldwide.
Collapse
Affiliation(s)
| | - Mallika Sengupta
- Microbiology, AIIMS Kalyani, Basantapur, Saguna, West Bengal, India
| | | | - Kiranmay Majee
- Student, AIIMS Kalyani, Basantapur, Saguna, West Bengal, India
| |
Collapse
|
7
|
Bron GM, Wichgers Schreur PJ, de Jong MCM, van Keulen L, Vloet RPM, Koenraadt CJM, Kortekaas J, ten Bosch QA. Quantifying Rift Valley fever virus transmission efficiency in a lamb-mosquito-lamb model. Front Cell Infect Microbiol 2023; 13:1206089. [PMID: 38170150 PMCID: PMC10759236 DOI: 10.3389/fcimb.2023.1206089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 10/30/2023] [Indexed: 01/05/2024] Open
Abstract
Rift Valley fever virus (RVFV) is a (re)emerging mosquito-borne pathogen impacting human and animal health. How RVFV spreads through a population depends on population-level and individual-level interactions between vector, host and pathogen. Here, we estimated the probability for RVFV to transmit to naive animals by experimentally exposing lambs to a bite of an infectious mosquito, and assessed if and how RVFV infection subsequently developed in the exposed animal. Aedes aegypti mosquitoes, previously infected via feeding on a viremic lamb, were used to expose naive lambs to the virus. Aedes aegypti colony mosquitoes were used as they are easy to maintain and readily feed in captivity. Other mosquito spp. could be examined with similar methodology. Lambs were exposed to either 1-3 (low exposure) or 7-9 (high exposure) infectious mosquitoes. All lambs in the high exposure group became viremic and showed characteristic signs of Rift Valley fever within 2-4 days post exposure. In contrast, 3 out of 12 lambs in the low exposure group developed viremia and disease, with similar peak-levels of viremia as the high exposure group but with some heterogeneity in the onset of viremia. These results suggest that the likelihood for successful infection of a ruminant host is affected by the number of infectious mosquitoes biting, but also highlights that a single bite of an infectious mosquito can result in disease. The per bite mosquito-to-host transmission efficiency was estimated at 28% (95% confidence interval: 15 - 47%). We subsequently combined this transmission efficiency with estimates for life traits of Aedes aegypti or related mosquitoes into a Ross-McDonald mathematical model to illustrate scenarios under which major RVFV outbreaks could occur in naïve populations (i.e., R0 >1). The model revealed that relatively high vector-to-host ratios as well as mosquitoes feeding preferably on competent hosts are required for R0 to exceed 1. Altogether, this study highlights the importance of experiments that mimic natural exposure to RVFV. The experiments facilitate a better understanding of the natural progression of disease and a direct way to obtain epidemiological parameters for mathematical models.
Collapse
Affiliation(s)
- Gebbiena M. Bron
- Quantitative Veterinary Epidemiology, Wageningen University and Research, Wageningen, Netherlands
| | | | - Mart C. M. de Jong
- Quantitative Veterinary Epidemiology, Wageningen University and Research, Wageningen, Netherlands
| | - Lucien van Keulen
- Wageningen Bioveterinary Research, Wageningen University and Research, Lelystad, Netherlands
| | - Rianka P. M. Vloet
- Wageningen Bioveterinary Research, Wageningen University and Research, Lelystad, Netherlands
| | | | - Jeroen Kortekaas
- Wageningen Bioveterinary Research, Wageningen University and Research, Lelystad, Netherlands
| | - Quirine A. ten Bosch
- Quantitative Veterinary Epidemiology, Wageningen University and Research, Wageningen, Netherlands
| |
Collapse
|
8
|
Tinto B, Quellec J, Cêtre-Sossah C, Dicko A, Salinas S, Simonin Y. Rift Valley fever in West Africa: A zoonotic disease with multiple socio-economic consequences. One Health 2023; 17:100583. [PMID: 37664171 PMCID: PMC10474305 DOI: 10.1016/j.onehlt.2023.100583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 06/12/2023] [Accepted: 06/12/2023] [Indexed: 09/05/2023] Open
Abstract
Rift Valley fever virus (RVFV) is an arbovirus that causes Rift Valley fever (RVF), a zoonotic disease that mainly affects domestic and wildlife ruminants and humans. The first epidemic in North-Western and West Africa occurred in Senegal and Mauritania in 1987, two countries where RVF is now endemic. Slaughterhouse workers, farmers, herders and veterinarians are at high risk of exposure to RVF. Beyond the health threat, RVF is considered to cause major socio-economic problems, specifically in developing countries where livestock farming and trade are important economic activities. Indeed, the mortality rate linked to RVF infection can reach 95-100% in newborns and young animals. In West Africa, livestock production is a key factor for food production and for national economics. Epizootics caused by RVF can therefore have serious socio-economic consequences by impacting multisectoral economics, the psycho-social health of pastoral communities, and food security. Improving prevention strategies against RVF, including vaccination, enhancing knowledge of RVF and correcting any inappropriate behaviors by populations of endemics areas, as well as better monitoring of RVF ecological factors are effective ways to better foresee and control outbreaks of RVF and its socio-economical side-effects in countries at high risk of occurrence of the disease.
Collapse
Affiliation(s)
- Bachirou Tinto
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
- Laboratoire National de Référence des Fièvres Hémorragiques Virale, Centre MURAZ, Institut National de Santé Publique (INSP), Bobo-Dioulasso, Burkina Faso
| | - Jordan Quellec
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
- ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France
| | | | - Amadou Dicko
- Laboratoire central de référence, Institut National de Santé Publique (INSP), Ouagadougou, Burkina Faso
- Ministère de l'Agriculture, des ressources animales et halieutiques du Burkina Faso, Ouagadougou, Burkina Faso
| | - Sara Salinas
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
| | - Yannick Simonin
- Pathogenesis and Control of Chronic and Emerging Infections, University of Montpellier, INSERM, Etablissement Français du Sang, Montpellier, France
- ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France
| |
Collapse
|
9
|
García García KM, Apolloni A, Giacomini A, Ciss M, Fall M, Marème Gaye A, Arsevska E, Mesdour A, Chevanne E, Rosso F, Cardinale E, Squarzoni Diaw C, Seck I, Lo M, Delabouglise A. Environmental and economic determinants of temporal dynamics of the ruminant movement network of Senegal. Sci Rep 2023; 13:14482. [PMID: 37660087 PMCID: PMC10475130 DOI: 10.1038/s41598-023-40715-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 08/16/2023] [Indexed: 09/04/2023] Open
Abstract
Our understanding of the drivers of the temporal dynamics of livestock mobility networks is currently limited, despite their significant implications for the surveillance and control of infectious diseases. We analyzed the effect of time-varying environmental and economic variables-biomass production, rainfall, livestock market prices, and religious calendar on long-distance movements of cattle and small ruminant herds in Senegal in the years 2014 and 2019. We used principal component analysis to explore the variation of the hypothesized explanatory variables in space and time and a generalized additive modelling approach to assess the effect of those variables on the likelihood of herd movement between pairs of administrative units. Contrary to environmental variables, the patterns of variation of market prices show significant differences across locations. The explanatory variables at origin had the highest contribution to the model deviance reduction. Biomass production and rainfall were found to affect the likelihood of herd movement for both species on at least 1 year. Market price at origin had a strong and consistent effect on the departure of small ruminant herds. Our study shows the potential benefits of regular monitoring of market prices for future efforts at forecasting livestock movements and associated sanitary risks.
Collapse
Affiliation(s)
| | - Andrea Apolloni
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Univ Montpellier, INRAE, Montpellier, France
| | - Alessandra Giacomini
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Univ Montpellier, INRAE, Montpellier, France
- Department of Biosciences, Swansea University, Swansea, SA2 8PP, UK
| | - Mamadou Ciss
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Sénégal
| | | | | | - Elena Arsevska
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Univ Montpellier, INRAE, Montpellier, France
| | - Asma Mesdour
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Univ Montpellier, INRAE, Montpellier, France
| | - Etienne Chevanne
- Food and Agriculture Organization of the United Nations, The European Commission for the Control of Foot-and-Mouth Disease, Rome, Italy
| | - Fabrizio Rosso
- Food and Agriculture Organization of the United Nations, The European Commission for the Control of Foot-and-Mouth Disease, Rome, Italy
| | - Eric Cardinale
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Univ Montpellier, INRAE, Montpellier, France
| | - Cécile Squarzoni Diaw
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Univ Montpellier, INRAE, Montpellier, France
| | - Ismaila Seck
- Food and Agriculture Organization of the United Nations, One Health and Intelligence and Early Warning Office, Rome, Italy
| | - Mbargou Lo
- Direction des Services Vétérinaires, Dakar, Sénégal
| | - Alexis Delabouglise
- CIRAD, UMR ASTRE, Montpellier, France.
- CIRAD, UMR ASTRE, Univ Montpellier, INRAE, Montpellier, France.
| |
Collapse
|
10
|
Pichi F, Agarwal A, Neri P. Multimodal Imaging of Rift Valley Fever Outer Retinitis. Ocul Immunol Inflamm 2023; 31:1528-1532. [PMID: 35708457 DOI: 10.1080/09273948.2022.2087094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 02/28/2022] [Accepted: 06/03/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE To report a case of Rift Valley Fever retinitis studied with multimodal imaging. METHOD A 50-years-old man from Sudan, diagnosed with Rift Valley fever, presented with complete loss of vision in the right eye and visual impairment in the left. Multimodal imaging was performed at baseline and follow-up. RESULTS Upon examination, the right eye showed complete optic nerve atrophy, diffuse dot-blot hemorrhages and patches of retinitis. The left eye had a visual acuity of 20/40 with no anterior chamber nor vitreous inflammatory cells. Fundus examination of the left eye showed diffuse patches of retinitis that on SD-OCT were confined to the outer retina, with a retinal pigment epithelium reactive thickening. These areas of active retinitis where hypofluorescent on fluorescein angiography (blockage) and the RPE hypertrophy cause hyperautofluorescence. The patient was treated empirically with oral and intravitreal steroid to stabilize the course of the retina infection. On the 3 months follow up the areas of retinitis had consolidated with RPE sub-atrophy that cause hypoautofluorescence. The left eye visual acuity was stable. CONCLUSION Rift Valley Fever etina lesions seem to be confined to the outer retina, and optic nerve involvement with RNFL loss seems to be the main cause of vision loss when the macula is spared.
Collapse
Affiliation(s)
- Francesco Pichi
- Eye Institute, Cleveland Clinic, Abu Dhabi, United Arab Emirates
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | | | - Piergiorgio Neri
- Eye Institute, Cleveland Clinic, Abu Dhabi, United Arab Emirates
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| |
Collapse
|
11
|
Ebogo‐Belobo JT, Kenmoe S, Abanda NN, Bowo‐Ngandji A, Mbaga DS, Magoudjou‐Pekam JN, Kame‐Ngasse GI, Tchatchouang S, Menkem EZ, Okobalemba EA, Noura EA, Meta‐Djomsi D, Maïdadi‐Foudi M, Kenfack‐Zanguim J, Kenfack‐Momo R, Kengne‐Nde C, Esemu SN, Mbacham WF, Sadeuh‐Mba SA, Ndip L, Njouom R. Contemporary epidemiological data of Rift Valley fever virus in humans, mosquitoes and other animal species in Africa: A systematic review and meta-analysis. Vet Med Sci 2023; 9:2309-2328. [PMID: 37548116 PMCID: PMC10508527 DOI: 10.1002/vms3.1238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/29/2023] [Accepted: 07/21/2023] [Indexed: 08/08/2023] Open
Abstract
Rift Valley fever (RVF) is a severe zoonotic mosquito-borne disease that represents an important threat to human and animal health, with major public health and socioeconomic impacts. This disease is endemic throughout many African countries and the Arabian Peninsula. This systematic review with meta-analysis was conducted to determine the RVF prevalence in humans, mosquitoes and other animal species in Africa. The review also provides contemporary data on RVF case fatality rate (CFR) in humans. In this systematic review with meta-analysis, a comprehensive literature search was conducted on the PubMed, Embase, Web of Science and Global Index Medicus databases from January 2000 to June 2022 to identify relevant studies. Pooled CFR and prevalence estimates were calculated using the random-effects model. Subgroup analysis and sensitivity analysis were performed, and the I2 -statistic was used to investigate a potential source of heterogeneity. A total of 205 articles were included in the final analysis. The overall RVF CFR in humans was found to be 27.5% [95% CI = 8.0-52.5]. The overall pooled prevalence was 7.8% [95% CI = 6.2-9.6] in humans and 9.3% [95% CI = 8.1-10.6] in animals, respectively. The RVF prevalence in individual mosquitoes ranged from 0.0% to 25%. Subgroup analysis showed substantial heterogeneity with respect to geographical regions and human categories. The study shows that there is a correspondingly similar prevalence of RVF in human and animals; however, human CFR is much higher than the observed prevalence. The lack of a surveillance programme and the fact that this virus has subclinical circulation in animals and humans could explain these observations. The implementation of a One Health approach for RVF surveillance and control would be of great interest for human and animal health.
Collapse
Affiliation(s)
- Jean Thierry Ebogo‐Belobo
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Sebastien Kenmoe
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Ngu Njei Abanda
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
| | - Arnol Bowo‐Ngandji
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Donatien Serge Mbaga
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | | | - Ginette Irma Kame‐Ngasse
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | | | | | - Efietngab Atembeh Noura
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Dowbiss Meta‐Djomsi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Martin Maïdadi‐Foudi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | - Raoul Kenfack‐Momo
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Cyprien Kengne‐Nde
- Epidemiological Surveillance, Evaluation and Research UnitNational AIDS Control CommitteeYaoundéCameroon
| | | | - Wilfred Fon Mbacham
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Serge Alain Sadeuh‐Mba
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
- Maryland Department of AgricultureSalisbury Animal Health LaboratorySalisburyMarylandUSA
| | - Lucy Ndip
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Richard Njouom
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
| |
Collapse
|
12
|
Sankhe S, Talla C, Thiam MS, Faye M, Barry MA, Diarra M, Dia M, Ndiaye O, Sembene PM, Diop B, Fall G, Faye O, Faye O, Diagne MM, Loucoubar C. Seroprevalence of Crimean-Congo Hemorrhagic Fever Virus and Rift Valley Fever Virus in human population in Senegal from October to November 2020. IJID REGIONS 2023; 7:216-221. [PMID: 37153883 PMCID: PMC10160495 DOI: 10.1016/j.ijregi.2023.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/24/2023] [Accepted: 03/27/2023] [Indexed: 05/10/2023]
Abstract
Objectives Rift Valley Fever and Crimean-Congo Hemorrhagic Fever are two infections classified among the emerging diseases to be monitored with highest priority. Studies undertaken in human and animals have shown endemicity of these two arboviruses in several African countries. However, most of the investigations were carried out on domestic cattle and the studies conducted on human populations are either outdated or limited to a small number of well-known endemic areas. It is then critical to better evaluate the burden of these viruses in Senegal at a national scale. Methods This work relies on a previous seroprevalence survey undertaken in all regions of Senegal at the end of 2020. The existing biobank was used to determine the immunoglobulin G [IgG] Rift Valley Fever and Crimean-Congo Hemorrhagic Fever seroprevalences by indirect enzyme-linked immunosorbent assay. Results The crude seroprevalences of Rift Valley Fever and Crimean-Congo Hemorrhagic Fever were 3.94% and 0.7% respectively, with the northern and central part of the countries as the main exposed areas. However, acute infections reported in both high and low exposed regions suggest sporadic introductions. Conclusions This study gives updated information and could be of interest to support the stakeholders in the management of these zoonoses.
Collapse
Affiliation(s)
- Safietou Sankhe
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
- Animal Biology Department, Faculty of Sciences and Techniques, Cheikh Anta Diop University of Dakar, Dakar, Senegal
| | - Cheikh Talla
- Epidemiology, Clinical Research and Data Science Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Mareme Seye Thiam
- Epidemiology, Clinical Research and Data Science Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Martin Faye
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Mamadou Aliou Barry
- Epidemiology, Clinical Research and Data Science Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Maryam Diarra
- Epidemiology, Clinical Research and Data Science Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Moussa Dia
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Oumar Ndiaye
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Pape Mbacke Sembene
- Animal Biology Department, Faculty of Sciences and Techniques, Cheikh Anta Diop University of Dakar, Dakar, Senegal
| | - Boly Diop
- Epidemiological Surveillance Division, Prevention Department, Ministry of Health, Dakar, Senegal
| | - Gamou Fall
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Oumar Faye
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Ousmane Faye
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| | - Moussa Moise Diagne
- Arboviruses and Hemorrhagic Fever Viruses Unit, Virology Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
- Corresponding author
| | - Cheikh Loucoubar
- Epidemiology, Clinical Research and Data Science Department, Institut Pasteur de Dakar, BP220 Dakar, Senegal
| |
Collapse
|
13
|
Human and Livestock Surveillance Revealed the Circulation of Rift Valley Fever Virus in Agnam, Northern Senegal, 2021. Trop Med Infect Dis 2023; 8:tropicalmed8020087. [PMID: 36828503 PMCID: PMC9962223 DOI: 10.3390/tropicalmed8020087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/08/2023] [Accepted: 01/20/2023] [Indexed: 02/03/2023] Open
Abstract
The mosquito-borne disease caused by the Rift Valley Fever Virus (RVFV) is a viral hemorrhagic fever that affects humans and animals. In 1987, RVFV emerged in Mauritania, which caused the first RVFV outbreak in West Africa. This outbreak was shortly followed by reported cases in humans and livestock in Senegal. Animal trade practices with neighboring Mauritania suggest northern regions of Senegal are at high risk for RVF. In this study, we aim to conduct a molecular and serological survey of RVFV in humans and livestock in Agnam (northeastern Senegal) by RT-PCR (reverse transcription real-time polymerase chain reaction) and ELISA (Enzyme-Linked Immunosorbent Assay), respectively. Of the two hundred fifty-five human sera, one (0.39%) tested RVFV IgM positive, while fifty-three (20.78%) tested positive for RVFV IgG. For animal monitoring, out of 30 sheep recorded and sampled over the study period, 20 (66.67%) showed seroconversion to RVFV IgG antibodies, notably during the rainy season. The presence of antibodies increased significantly with age in both groups (p < 0.05), as the force of RVF infection (FOI), increased by 16.05% per year for humans and by 80.4% per month for livestock sheep. This study supports the usefulness of setting up a One Health survey for RVF management.
Collapse
|
14
|
Ossebi W, Ndjoug Ndour AP, Dieng SD, Bedekelabou AP, Kalandi M, Diop FN, Bada Alambedji R, Kaboret YY, Faye A, Sambou B. One Health training needs for Senegalese professionals to manage emerging public health threats. SCIENCE IN ONE HEALTH 2022; 1:100005. [PMID: 39076607 PMCID: PMC11262269 DOI: 10.1016/j.soh.2022.100005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/22/2022] [Indexed: 07/31/2024]
Abstract
Global health trends, marked by increasing epidemics and pandemics, call for enhanced human resource preparedness to prevent and respond to emerging and future health problems. Indeed, according to the World Organization for Animal Health (WOAH), at least 75% of the pathogens responsible for emerging and re-emerging human infectious diseases originate from animals. These health problems involve environmental, economic and social factors. Because of their multidimensional nature, addressing these health problems requires the adoption of a One Health approach. To achieve this, training of human resources is a priority. This descriptive cross-sectional study was conducted from September 12 to 22, 2021 in 6 regions of Senegal, namely, Dakar, Thiès, Diourbel, Kaolack, Saint-Louis, and Ziguinchor. Questionnaires were administered online and in person to 217 professionals in human, environmental, animal health and agriculture. Data were statistically processed, and bivariate analyses enabled a better correlation between training needs for professionals according to their occupational group. The survey sample was 64% male and 36% female. More than half of the professionals surveyed (53.5%) had less than 10 years of experience. Human health workers were the most represented (46%), followed by animal health workers (34%) and environmental workers (16%). Agriculture, fisheries, and food security were weakly represented. Few had received training in the One Health approach and entry-level One Health skills predominated. The One Health competencies in which professionals want to build capacity differ by sector. Globally, public health and epidemiology, health risk management, basic of One Health concepts, animal health and biotechnology are the priorities. The development of training programs could then enable these expressed needs to be addressed.
Collapse
Affiliation(s)
- Walter Ossebi
- Inter-State School of Veterinary Sciences and Medicine, Cheikh Anta Diop University, Dakar-Fann BP, 5077, Senegal
| | - Andrée Prisca Ndjoug Ndour
- Inter-State School of Veterinary Sciences and Medicine, Cheikh Anta Diop University, Dakar-Fann BP, 5077, Senegal
| | - Sara Danièle Dieng
- Inter-State School of Veterinary Sciences and Medicine, Africa One Health University Network, Dakar-Fann BP, 5077, Senegal
- Institute of Environmental Sciences, Cheikh Anta Diop University, Dakar-Fann BP, 5005, Senegal
| | | | - Miguiri Kalandi
- Inter-State School of Veterinary Sciences and Medicine, Cheikh Anta Diop University, Dakar-Fann BP, 5077, Senegal
| | - Fatimata Niang Diop
- Institute of Environmental Sciences, Cheikh Anta Diop University, Dakar-Fann BP, 5005, Senegal
| | - Rianatou Bada Alambedji
- Inter-State School of Veterinary Sciences and Medicine, Cheikh Anta Diop University, Dakar-Fann BP, 5077, Senegal
| | - Yalacé Yamba Kaboret
- Inter-State School of Veterinary Sciences and Medicine, Cheikh Anta Diop University, Dakar-Fann BP, 5077, Senegal
| | - Adama Faye
- Institute of Health and Development, Cheikh Anta Diop University, Dakar-Fann BP, 5005, Senegal
| | - Bienvenu Sambou
- Institute of Environmental Sciences, Cheikh Anta Diop University, Dakar-Fann BP, 5005, Senegal
| |
Collapse
|
15
|
Anywaine Z, Lule SA, Hansen C, Warimwe G, Elliott A. Clinical manifestations of Rift Valley fever in humans: Systematic review and meta-analysis. PLoS Negl Trop Dis 2022; 16:e0010233. [PMID: 35333856 PMCID: PMC8986116 DOI: 10.1371/journal.pntd.0010233] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 04/06/2022] [Accepted: 02/03/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Rift Valley fever (RVF) is an emerging, neglected, mosquito-borne viral zoonosis associated with significant morbidity, mortality and expanding geographical scope. The clinical signs and symptoms in humans are non-specific and case definitions vary. We reviewed and analysed the clinical manifestations of RVF in humans. METHODS In this systematic review and meta-analysis we searched on different dates, the Embase (from 1947 to 13th October 2019), Medline (1946 to 14th October 2019), Global Health (1910 to 15th October 2019), and Web of Science (1970 to 15th October 2019) databases. Studies published in English, reporting frequency of symptoms in humans, and laboratory confirmed RVF were included. Animal studies, studies among asymptomatic volunteers, and single case reports for which a proportion could not be estimated, were excluded. Quality assessment was done using a modified Hoy and Brooks et al tool, data was extracted, and pooled frequency estimates calculated using random effects meta-analysis. RESULTS Of the 3765 articles retrieved, less than 1% (32 articles) were included in the systematic review and meta-analysis. Nine RVF clinical syndromes were reported including the general febrile, renal, gastrointestinal, hepatic, haemorrhagic, visual, neurological, cardio-pulmonary, and obstetric syndromes. The most common clinical manifestations included fever (81%; 95% Confidence Interval (CI) 69-91; [26 studies, 1286 patients]), renal failure (41%; 23-59; [4, 327]), nausea (38%; 12-67; [6, 325]), jaundice (26%; 16-36; [15, 393]), haemorrhagic disease (26%; 17-36; [16, 277]), partial blindness (24%; 7-45; [11, 225]), encephalitis (21%; 11-33; [4, 327]), cough (4%; 0-17; [4, 11]), and miscarriage (54%) respectively. Death occurred in 21% (95% CI 14-29; [16 studies, 328 patients]) of cases, most of whom were hospitalised. DISCUSSION This study delineates the complex symptomatology of human RVF disease into syndromes. This approach is likely to improve case definitions and detection rates, impact outbreak control, increase public awareness about RVF, and subsequently inform 'one-health' policies. This study provides a pooled estimate of the proportion of RVF clinical manifestations alongside a narrative description of clinical syndromes. However, most studies reviewed were case series with small sample sizes and enrolled mostly in-patients and out-patients, and captured symptoms either sparsely or using broad category terms.
Collapse
Affiliation(s)
- Zacchaeus Anywaine
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Entebbe, Uganda
- * E-mail:
| | - Swaib Abubaker Lule
- Institute for Global Health, University College London, London, United Kingdom
| | - Christian Hansen
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Entebbe, Uganda
- MRC International Statistics & Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - George Warimwe
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
- KEMRI WellcomeTrust Research Programme, Kilifi, Kenya
| | - Alison Elliott
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| |
Collapse
|
16
|
Gerken KN, LaBeaud AD, Mandi H, L’Azou Jackson M, Breugelmans JG, King CH. Paving the way for human vaccination against Rift Valley fever virus: A systematic literature review of RVFV epidemiology from 1999 to 2021. PLoS Negl Trop Dis 2022; 16:e0009852. [PMID: 35073355 PMCID: PMC8812886 DOI: 10.1371/journal.pntd.0009852] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 02/03/2022] [Accepted: 12/22/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Rift Valley fever virus (RVFV) is a lethal threat to humans and livestock in many parts of Africa, the Arabian Peninsula, and the Indian Ocean. This systematic review's objective was to consolidate understanding of RVFV epidemiology during 1999-2021 and highlight knowledge gaps relevant to plans for human vaccine trials. METHODOLOGY/PRINCIPAL FINDINGS The review is registered with PROSPERO (CRD42020221622). Reports of RVFV infection or exposure among humans, animals, and/or vectors in Africa, the Arabian Peninsula, and the Indian Ocean during the period January 1999 to June 2021 were eligible for inclusion. Online databases were searched for publications, and supplemental materials were recovered from official reports and research colleagues. Exposures were classified into five groups: 1) acute human RVF cases, 2) acute animal cases, 3) human RVFV sero-surveys, 4) animal sero-surveys, and 5) arthropod infections. Human risk factors, circulating RVFV lineages, and surveillance methods were also tabulated. In meta-analysis of risks, summary odds ratios were computed using random-effects modeling. 1104 unique human or animal RVFV transmission events were reported in 39 countries during 1999-2021. Outbreaks among humans or animals occurred at rates of 5.8/year and 12.4/year, respectively, with Mauritania, Madagascar, Kenya, South Africa, and Sudan having the most human outbreak years. Men had greater odds of RVFV infection than women, and animal contact, butchering, milking, and handling aborted material were significantly associated with greater odds of exposure. Animal infection risk was linked to location, proximity to water, and exposure to other herds or wildlife. RVFV was detected in a variety of mosquito vectors during interepidemic periods, confirming ongoing transmission. CONCLUSIONS/SIGNIFICANCE With broad variability in surveillance, case finding, survey design, and RVFV case confirmation, combined with uncertainty about populations-at-risk, there were inconsistent results from location to location. However, it was evident that RVFV transmission is expanding its range and frequency. Gaps assessment indicated the need to harmonize human and animal surveillance and improve diagnostics and genotyping. Given the frequency of RVFV outbreaks, human vaccination has strong potential to mitigate the impact of this now widely endemic disease.
Collapse
Affiliation(s)
- Keli N. Gerken
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - A. Desirée LaBeaud
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Henshaw Mandi
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | | | | | - Charles H. King
- Center for Global Health and Diseases, Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| |
Collapse
|
17
|
Bob NS, Barry MA, Diagne MM, Faye M, Ndione MHD, Diallo A, Diop M, Diop B, Faye O, Loucoubar C, Fall G, Faye O. Detection of Rift Valley Fever Virus Lineage H from South Africa through Syndromic Sentinel Surveillance Network in Senegal. Open Forum Infect Dis 2021; 9:ofab655. [PMID: 35198642 PMCID: PMC8860161 DOI: 10.1093/ofid/ofab655] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/27/2021] [Indexed: 11/23/2022] Open
Abstract
Background Rift Valley fever virus (RVFV) is an arbovirus that causes epizootics and epidemics among livestock population and humans. Our surveillance system has revealed multiple emergences and re-emergences of RVFV in West Africa over the last decade. Methods The Sentinel Syndromic Surveillance Network in Senegal (4S) has been implemented since 2011. Samples from human suspected arbovirus infection in 4S sentinel sites were sent to Institut Pasteur de Dakar (IPD), where arbovirus diagnosis by enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription polymerase chain reaction (RT-PCR), and virus isolation was performed. Overall, IPD has received a total of 1149 samples from arboviral suspected patients through the 4S network from January to December 2020. These samples were screened for 7 arboviruses including RVFV. Whole-genome sequencing of positive RVFV samples by RT-PCR was performed using the Illumina Miseq platform followed by genome assembly. Phylogenetic analyses were performed using MEGA X. Results Out of the 1149 arbovirus suspected cases, 4 RVFV-positive samples were detected with RT-PCR while 5 RVFV-positive samples were detected by ELISA. Complete genome sequences were obtained for 3 strains among the 4 positive samples by RT-PCR. Phylogenetic analyses indicated an emergence of a virus first described in South Africa during a major outbreak. Conclusions This strong surveillance system allowed the detection of an RVFV outbreak in Senegal in 2020. The obtained genomes clustered with strains from South Africa belonging to lineage H. This calls for implementation of a strong surveillance system for wild animals, humans, and livestock simultaneously in all African countries.
Collapse
Affiliation(s)
| | | | | | - Martin Faye
- Pole of virology, Institut Pasteur of Dakar, Senegal
| | | | - Amadou Diallo
- Epidemiological unit, Institut Pasteur of Dakar,Senegal
| | - Mamadou Diop
- Epidemiological unit, Institut Pasteur of Dakar,Senegal
| | | | - Oumar Faye
- Pole of virology, Institut Pasteur of Dakar, Senegal
| | | | - Gamou Fall
- Pole of virology, Institut Pasteur of Dakar, Senegal
| | - Ousmane Faye
- Pole of virology, Institut Pasteur of Dakar, Senegal
| |
Collapse
|
18
|
Cecilia H, Métras R, Fall AG, Lo MM, Lancelot R, Ezanno P. It's risky to wander in September: Modelling the epidemic potential of Rift Valley fever in a Sahelian setting. Epidemics 2020; 33:100409. [PMID: 33137548 DOI: 10.1016/j.epidem.2020.100409] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 08/27/2020] [Accepted: 09/16/2020] [Indexed: 11/15/2022] Open
Abstract
Estimating the epidemic potential of vector-borne diseases, along with the relative contribution of underlying mechanisms, is crucial for animal and human health worldwide. In West African Sahel, several outbreaks of Rift Valley fever (RVF) have occurred over the last decades, but uncertainty remains about the conditions necessary to trigger these outbreaks. We use the basic reproduction number (R0) as a measure of RVF epidemic potential in northern Senegal, and map its value in two distinct ecosystems, namely the Ferlo and the Senegal River delta and valley. We consider three consecutive rainy seasons (July-November 2014, 2015 and 2016) and account for several vector and animal species. We parametrize our model with estimates of Aedes vexans arabiensis, Culex poicilipes, Culex tritaeniorhynchus, cattle, sheep and goat abundances. The impact of RVF virus introduction is assessed every week over northern Senegal. We highlight September as the period of highest epidemic potential in northern Senegal, resulting from distinct dynamics in the two study areas. Spatially, in the seasonal environment of the Ferlo, we observe that high-risk locations vary between years. We show that decreased vector densities do not greatly reduce R0 and that cattle immunity has a greater impact on reducing transmission than small ruminant immunity. The host preferences of vectors and the temperature-dependent time interval between their blood meals are crucial parameters needing further biological investigations.
Collapse
Affiliation(s)
- Hélène Cecilia
- INRAE, Oniris, BIOEPAR, 44300, Nantes, France; UMR ASTRE, CIRAD, Montpellier, France; ASTRE, Montpellier University, CIRAD, INRAE, Montpellier, France.
| | - Raphaëlle Métras
- Inserm, Sorbonne Université, Institut Pierre Louis d'Epidémiologie et de Santé Publique (IPLESP), F-75012, Paris, France.
| | - Assane Gueye Fall
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal.
| | - Modou Moustapha Lo
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal.
| | - Renaud Lancelot
- UMR ASTRE, CIRAD, Montpellier, France; ASTRE, Montpellier University, CIRAD, INRAE, Montpellier, France.
| | | |
Collapse
|
19
|
Hardcastle AN, Osborne JCP, Ramshaw RE, Hulland EN, Morgan JD, Miller-Petrie MK, Hon J, Earl L, Rabinowitz P, Wasserheit JN, Gilbert M, Robinson TP, Wint GRW, Shirude S, Hay SI, Pigott DM. Informing Rift Valley Fever preparedness by mapping seasonally varying environmental suitability. Int J Infect Dis 2020; 99:362-372. [PMID: 32738486 PMCID: PMC7562817 DOI: 10.1016/j.ijid.2020.07.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/09/2020] [Accepted: 07/24/2020] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Rift Valley Fever (RVF) poses a threat to human and animal health throughout much of Africa and the Middle East and has been recognized as a global health security priority and a key preparedness target. METHODS We combined RVF occurrence data from a systematic literature review with animal notification data from an online database. Using boosted regression trees, we made monthly environmental suitability predictions from January 1995 to December 2016 at a 5 × 5-km resolution throughout regions of Africa, Europe, and the Middle East. We calculated the average number of months per year suitable for transmission, the mean suitability for each calendar month, and the "spillover potential," a measure incorporating suitability with human and livestock populations. RESULTS Several countries where cases have not yet been reported are suitable for RVF. Areas across the region of interest are suitable for transmission at different times of the year, and some areas are suitable for multiple seasons each year. Spillover potential results show areas within countries where high populations of humans and livestock are at risk for much of the year. CONCLUSIONS The widespread environmental suitability of RVF highlights the need for increased preparedness, even in countries that have not previously experienced cases. These maps can aid in prioritizing long-term RVF preparedness activities and determining optimal times for recurring preparedness activities. Given an outbreak, our results can highlight areas often at risk for subsequent transmission that month, enabling decision-makers to target responses effectively.
Collapse
Affiliation(s)
- Austin N Hardcastle
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Joshua C P Osborne
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Rebecca E Ramshaw
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Erin N Hulland
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Julia D Morgan
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Molly K Miller-Petrie
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Julia Hon
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Lucas Earl
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Peter Rabinowitz
- Department of Global Health, University of Washington, Seattle, WA, USA
| | | | - Marius Gilbert
- Spatial Epidemiology Lab (SpELL), Université Libre de Bruxelles, Brussels, Belgium; Fonds National de la Recherche Scientifique (FNRS), Brussels, Belgium
| | - Timothy P Robinson
- Animal Production and Health Division (AGA), Food and Agriculture Organization of the United Nations, Italy
| | - G R William Wint
- Environmental Research Group Oxford (ERGO), c/o Department of Zoology, Oxford, UK
| | - Shreya Shirude
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| | - Simon I Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA; Department of Health Metrics Sciences, School of Medicine, University of Washington, Seattle, WA, USA
| | - David M Pigott
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA; Department of Health Metrics Sciences, School of Medicine, University of Washington, Seattle, WA, USA.
| |
Collapse
|
20
|
Kroeker AL, Babiuk S, Pickering BS, Richt JA, Wilson WC. Livestock Challenge Models of Rift Valley Fever for Agricultural Vaccine Testing. Front Vet Sci 2020; 7:238. [PMID: 32528981 PMCID: PMC7266933 DOI: 10.3389/fvets.2020.00238] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 04/07/2020] [Indexed: 11/13/2022] Open
Abstract
Since the discovery of Rift Valley Fever virus (RVFV) in Kenya in 1930, the virus has become widespread throughout most of Africa and is characterized by sporadic outbreaks. A mosquito-borne pathogen, RVFV is poised to move beyond the African continent and the Middle East and emerge in Europe and Asia. There is a risk that RVFV could also appear in the Americas, similar to the West Nile virus. In light of this potential threat, multiple studies have been undertaken to establish international surveillance programs and diagnostic tools, develop models of transmission dynamics and risk factors for infection, and to develop a variety of vaccines as countermeasures. Furthermore, considerable efforts to establish reliable challenge models of Rift Valley fever virus have been made and platforms for testing potential vaccines and therapeutics in target species have been established. This review emphasizes the progress and insights from a North American perspective to establish challenge models in target livestock such as cattle, sheep, and goats in comparisons to other researchers' reports. A brief summary of the potential role of wildlife, such as buffalo and white-tailed deer as reservoir species will also be discussed.
Collapse
Affiliation(s)
- Andrea Louise Kroeker
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Shawn Babiuk
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - Bradley S Pickering
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Juergen A Richt
- Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), Manhattan, KS, United States
| | - William C Wilson
- USDA, Arthropod-Borne Animal Diseases Research Unit (ABADRU), Manhattan, KS, United States
| |
Collapse
|
21
|
Grossi-Soyster EN, LaBeaud AD. Rift Valley Fever: Important Considerations for Risk Mitigation and Future Outbreaks. Trop Med Infect Dis 2020; 5:tropicalmed5020089. [PMID: 32498264 PMCID: PMC7345646 DOI: 10.3390/tropicalmed5020089] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/22/2020] [Accepted: 05/28/2020] [Indexed: 12/02/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a zoonotic phlebovirus of the Phenuiviridae family with great opportunity for emergence in previously unaffected regions, despite its current geographical limits. Outbreaks of RVFV often infect humans or domesticated animals, such as livestock, concurrently and occur sporadically, ranging from localized outbreaks in villages to multi-country events that spread rapidly. The true burden of Rift Valley fever (RVF) is not well defined due to underreporting, misdiagnosis caused by the broad spectrum of disease presentation, and minimal access for rapid and accurate laboratory confirmation. Severe symptoms may include hemorrhagic fever, loss of vision, psychological impairment or disturbances, and organ failure. Those living in endemic areas and travelers should be aware of the potential for exposure to ongoing outbreaks or interepidemic transmission, and engage in behaviors to minimize exposure risks, as vaccinations in humans are currently unavailable and animal vaccinations are not used routinely or ubiquitously. The lack of vaccines approved for use in humans is concerning, as RVFV has proven to be highly pathogenic in naïve populations, causing severe disease in a large percent of confirmed cases, which could have considerable impact on human health.
Collapse
|
22
|
Durand B, Lo Modou M, Tran A, Ba A, Sow F, Belkhiria J, Fall AG, Biteye B, Grosbois V, Chevalier V. Rift Valley fever in northern Senegal: A modelling approach to analyse the processes underlying virus circulation recurrence. PLoS Negl Trop Dis 2020; 14:e0008009. [PMID: 32479505 PMCID: PMC7289439 DOI: 10.1371/journal.pntd.0008009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/11/2020] [Accepted: 04/22/2020] [Indexed: 01/12/2023] Open
Abstract
Rift Valley fever (RVF) is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. To investigate the mechanisms that explain RVF recurrent circulation, we modelled a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics, and nomadic herd movements recorded in Younoufere area. To calibrate the model, serological surveys were performed in 2015–2016 on both resident and nomadic domestic herds in the same area. Mosquito population dynamics were obtained from a published model trained in the same region. Model comparison techniques were used to compare five different scenarios of virus introduction by nomadic herds associated or not with vertical transmission in Aedes vexans. Our serological results confirmed a long lasting RVF endemicity in resident herds (IgG seroprevalence rate of 15.3%, n = 222), and provided the first estimation of RVF IgG seroprevalence in nomadic herds in West Africa (12.4%, n = 660). Multivariate analysis of serological data suggested an amplification of the transmission cycle during the rainy season with a peak of circulation at the end of that season. The best scenario of virus introduction combined yearly introductions of RVFV from 2008 to 2015 (the study period) by nomadic herds, with a proportion of viraemic individuals predicted to be larger in animals arriving during the 2nd half of the rainy season (3.4%). This result is coherent with the IgM prevalence rate (4%) found in nomadic herds sampled during the 2nd half of the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, our model demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal. Rift Valley fever (RVF) is one of the most important vector borne disease in Africa, seriously affecting the health of domestic ruminants and humans and leading to severe economic consequences. This disease is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. Two non-exclusive mechanisms may support this endemicity: recurrent introductions of the virus by nomadic animals, and vertical transmission of the virus (i.e. from infected female mosquito to eggs) in local Aedes populations. The authors followed resident and nomadic domestic herds for 1 year. They used the data thus obtained to model a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics. They found that the best scenario explaining RVF remanence combined yearly introductions of RVFV by nomadic herds, with a viraemic proportion predicted to be larger in animals arriving during the 2nd half of the rainy season, which is consistent with an amplification of virus circulation in the area during the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, their results demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal.
Collapse
Affiliation(s)
- Benoit Durand
- Epidemiology Unit, Laboratory for Animal Health, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), University Paris-Est, Maisons-Alfort, France
- * E-mail: (BD); (VC)
| | | | - Annelise Tran
- CIRAD, UMR TETIS, Sainte-Clotilde, Réunion, France
- CIRAD, UMR ASTRE, Montpellier, France
- Université Montpellier, Montpellier, France
| | - Aminata Ba
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Fafa Sow
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Jaber Belkhiria
- Center for Animal Disease Modeling and Surveillance, Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, California, United States of America
| | | | - Biram Biteye
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | | | - Véronique Chevalier
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Phnom Penh, Cambodia
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- * E-mail: (BD); (VC)
| |
Collapse
|
23
|
Sagna AB, Kassié D, Couvray A, Adja AM, Hermann E, Riveau G, Salem G, Fournet F, Remoue F. Spatial Assessment of Contact Between Humans and Anopheles and Aedes Mosquitoes in a Medium-Sized African Urban Setting, Using Salivary Antibody-Based Biomarkers. J Infect Dis 2020; 220:1199-1208. [PMID: 31152664 DOI: 10.1093/infdis/jiz289] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/30/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Anarchic and poorly controlled urbanization led to an increased risk of mosquito-borne diseases (MBD) in many African cities. Here, we evaluate the spatial heterogeneity of human exposure to malaria and arboviral disease vectors in an urban area of northern Senegal, using antibody-based biomarkers of exposure to Anopheles and Aedes mosquito bites. METHODS A cross-sectional study was undertaken during the rainy season of 2014 in 4 neighborhoods of Saint-Louis, a city in northern Senegal. Among children aged 6-59 months in each neighborhood, the dried blood spot technique was used to evaluate immunoglobulin G (IgG) responses to both gSG6-P1 (Anopheles) and Nterm-34-kDa (Aedes) salivary peptides as validated biomarkers of respective mosquito bite exposure. RESULTS IgG response levels to gSG6-P1 and Nterm-34-kDa salivary peptides varied significantly between the 4 neighborhoods (P < .0001). The level of exposure to Aedes bites also varied according to household access to sanitation services (P = .027), whereas that of exposure to Anopheles bites varied according to insecticide-treated bed net use (P = .006). In addition, spatial clusters of high contact between humans and mosquitoes were identified inside 3 neighborhoods. CONCLUSIONS Antibody-based biomarkers of exposure to Anopheles and Aedes mosquito bites could be helpful tools for evaluating the heterogeneity of exposure to malaria and arboviral disease vectors by national control programs.
Collapse
Affiliation(s)
- André B Sagna
- MIVEGEC, University of Montpellier, CNRS, IRD
- Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte d'Ivoire
- Biomedical Research Center Espoir Pour La Santé, Saint-Louis, Sénégal
| | - Daouda Kassié
- ASTRE, University of Montpellier, CIRAD, INRA, Montpellier
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | | | - Akré Maurice Adja
- Institut Pierre Richet/Institut National de Santé Publique, Bouaké, Côte d'Ivoire
| | - Emmanuel Hermann
- CIIL, Institut Pasteur de Lille, University of Lille, CNRS UMR, Inserm, Lille, France
| | - Gilles Riveau
- CIIL, Institut Pasteur de Lille, University of Lille, CNRS UMR, Inserm, Lille, France
- Biomedical Research Center Espoir Pour La Santé, Saint-Louis, Sénégal
| | - Gérard Salem
- CEPED, University of Paris Descartes, IRD, Paris
| | - Florence Fournet
- MIVEGEC, University of Montpellier, CNRS, IRD
- Institut de Recherche en Sciences de la Santé, Bobo-Dioulasso, Burkina Faso
| | | |
Collapse
|
24
|
Biteye B, Fall AG, Seck MT, Ciss M, Diop M, Gimonneau G. Host-feeding patterns of Aedes (Aedimorphus) vexans arabiensis, a Rift Valley Fever virus vector in the Ferlo pastoral ecosystem of Senegal. PLoS One 2019; 14:e0215194. [PMID: 31584948 PMCID: PMC6777780 DOI: 10.1371/journal.pone.0215194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 09/20/2019] [Indexed: 12/02/2022] Open
Abstract
Background Host-vector contact is a key factor in vectorial capacity assessment and thus the transmission of mosquito-borne viruses such as Rift Valley Fever (RVF), an emerging zoonotic disease of interest in West Africa. The knowledge of the host-feeding patterns of vector species constitutes a key element in the assessment of their epidemiological importance in a given environment. The aim of this work was to identify the blood meal origins of the mosquito Aedes vexans arabiensis, the main vector of RVF virus in the Ferlo pastoral ecosystem of Senegal. Methodology/principal findings Engorged female mosquitoes were collected in Younouféré in the pastoral ecosystem in the Ferlo region during the 2014 rainy season. CO2-baited CDC light traps were set at six points for two consecutive nights every month from July to November. Domestic animals present around traps were identified and counted for each trapping session. Blood meal sources of engorged mosquitoes were identified using a vertebrate-specific multiplexed primer set based on cytochrome b. Blood meal sources were successfully identified for 319 out of 416 blood-fed females (76.68%), of which 163 (51.1%) were single meals, 146 (45.77%) mixed meals from two different hosts and 10 (3.13%) mixed meals from three different hosts. Aedes vexans arabiensis fed preferentially on mammals especially on horse compared to other hosts (FR = 46.83). Proportions of single and mixed meals showed significant temporal and spatial variations according to the availability of the hosts. Conclusion Aedes vexans arabiensis shows an opportunistic feeding behavior depending on the host availability. This species fed preferentially on mammals especially on horses (primary hosts) and ruminants (secondary hosts).
Collapse
Affiliation(s)
- Biram Biteye
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l’Elevage et de Recherches Vétérinaires BP 2057 Dakar-Hann, Sénégal
- * E-mail:
| | - Assane Gueye Fall
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l’Elevage et de Recherches Vétérinaires BP 2057 Dakar-Hann, Sénégal
| | - Momar Talla Seck
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l’Elevage et de Recherches Vétérinaires BP 2057 Dakar-Hann, Sénégal
| | - Mamadou Ciss
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l’Elevage et de Recherches Vétérinaires BP 2057 Dakar-Hann, Sénégal
| | - Mariame Diop
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l’Elevage et de Recherches Vétérinaires BP 2057 Dakar-Hann, Sénégal
| | - Geoffrey Gimonneau
- CIRAD, UMR INTERTRYP, Montpellier, France
- Centre International de Recherche–Développement sur l’Elevage en zone subhumide, Bobo-Dioulasso 01, Burkina Faso
- INTERTRYP, Univ Montpellier, CIRAD, IRD, Montpellier, France
| |
Collapse
|
25
|
Belkhiria J, Lo MM, Sow F, Martínez-López B, Chevalier V. Application of exponential random graph models to determine nomadic herders' movements in Senegal. Transbound Emerg Dis 2019; 66:1642-1652. [PMID: 30959578 DOI: 10.1111/tbed.13198] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 01/01/2023]
Abstract
Understanding human and animal mobility patterns is a key to predict local and global disease spread. We analysed the nomad herds' movement network in a pilot area of northern Senegal and used exponential random graph models (ERGM) to investigate the reasons behind these movements. We interviewed 132 nomadic herders to collect information about nomad herd structures, movements, and reasons for taking specific routes or gathering in certain areas. We constructed a spatially explicit network with villages as the nodes and nomad herds' movements as the connecting edges. The final ERGM showed that node and edge attributes such as presence of cattle in the herd (odds ratio = 12, CI: 5.3, 27.3), morbidity (odds ratio = 3.6, CI: 2.3, 5.7), and lack of water (odds ratio = 2, CI: 1.3, 3.1) were important predictors of nomad herds' movements. This study not only provides valuable information for monitoring important livestock diseases such as Rift Valley Fever in Senegal, but also helps implement outreach, education, and intervention programs for other emerging and endemic diseases affecting nomadic herds.
Collapse
Affiliation(s)
- Jaber Belkhiria
- Center for Animal Disease Modeling and Surveillance, Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, California
| | | | - Fafa Sow
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Beatriz Martínez-López
- Center for Animal Disease Modeling and Surveillance, Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, California
| | - Veronique Chevalier
- CIRAD, UMR ASTRE, Phnom Penh, Cambodia.,CIRAD, UMR, ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France.,Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| |
Collapse
|
26
|
Spatial Modeling of Mosquito Vectors for Rift Valley Fever Virus in Northern Senegal: Integrating Satellite-Derived Meteorological Estimates in Population Dynamics Models. REMOTE SENSING 2019. [DOI: 10.3390/rs11091024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mosquitoes are vectors of major pathogen agents worldwide. Population dynamics models are useful tools to understand and predict mosquito abundances in space and time. To be used as forecasting tools over large areas, such models could benefit from integrating remote sensing data that describe the meteorological and environmental conditions driving mosquito population dynamics. The main objective of this study is to assess a process-based modeling framework for mosquito population dynamics using satellite-derived meteorological estimates as input variables. A generic weather-driven model of mosquito population dynamics was applied to Rift Valley fever vector species in northern Senegal, with rainfall, temperature, and humidity as inputs. The model outputs using meteorological data from ground weather station vs satellite-based estimates are compared, using longitudinal mosquito trapping data for validation at local scale in three different ecosystems. Model predictions were consistent with field entomological data on adult abundance, with a better fit between predicted and observed abundances for the Sahelian Ferlo ecosystem, and for the models using in-situ weather data as input. Based on satellite-derived rainfall and temperature data, dynamic maps of three potential Rift Valley fever vector species were then produced at regional scale on a weekly basis. When direct weather measurements are sparse, these resulting maps should be used to support policy-makers in optimizing surveillance and control interventions of Rift Valley fever in Senegal.
Collapse
|
27
|
Lagare A, Fall G, Ibrahim A, Ousmane S, Sadio B, Abdoulaye M, Alhassane A, Mahaman AE, Issaka B, Sidikou F, Zaneidou M, Bienvenue B, Djingarey Mamoudou H, Bailo Diallo A, Kadadé G, Testa J, Boubacar Mainassara H, Faye O. First occurrence of Rift Valley fever outbreak in Niger, 2016. Vet Med Sci 2018; 5:70-78. [PMID: 30411868 PMCID: PMC6376139 DOI: 10.1002/vms3.135] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Rift Valley fever (RVF) is a mosquito‐borne viral zoonosis causing abortions and high mortality among animals, whereas in humans, the disease is usually mild or asymptomatic. In September 2016, the Republic of Niger declared the first RVF outbreak in the northern region of Tahoua near the Malian border. This study describes the outbreak and reports the results of serological and molecular investigations of the human and animal samples collected. Serum samples from both human and animal suspected cases have been confirmed at the Centre de Recherche Médicale et Sanitaire (CERMES) and the Laboratoire Centrale d'Elevage (LABOCEL) public health and animal reference laboratories, respectively. Techniques for biological confirmation were real time reverse transcription polymerase chain reaction (RT‐PCR) and enzyme linked immunosorbent assay (ELISA). Phylogenetic trees were established after genetic sequencing of the small and medium segments of the RVF virus (RVFV) genome. Out of the 399 human samples collected, 17 (4.3%) were confirmed positive for RVFV. Overall, 33 (8.3%) deaths occurred out of which five (29%) were among the 17 confirmed cases. Regarding animals, 45 samples were tested, three of which were RT‐PCR positive and 24 were IgG positive. The phylogenetic analyses showed that the Niger strains clustered with Senegal 2013 and Mauritania 2015 RVFV strains. This first outbreak of RVF was very challenging for public and animal health laboratories in Niger. Besides resulting in human deaths, important loss of cattle has been reported. Therefore, vigilance has to be strengthened emphasising vector control strategies and active surveillance among animals.
Collapse
Affiliation(s)
- Adamou Lagare
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | - Gamou Fall
- Arbovirus and Viral Hemorrhagic Fevers Unit, Institut Pasteur, Dakar, Sénégal
| | | | - Sani Ousmane
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | - Bacary Sadio
- Arbovirus and Viral Hemorrhagic Fevers Unit, Institut Pasteur, Dakar, Sénégal
| | | | | | - Ali Elh Mahaman
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | - Bassira Issaka
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | - Fati Sidikou
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | | | | | | | | | | | - Jean Testa
- Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | | | - Ousmane Faye
- Arbovirus and Viral Hemorrhagic Fevers Unit, Institut Pasteur, Dakar, Sénégal
| |
Collapse
|
28
|
Biteye B, Fall AG, Ciss M, Seck MT, Apolloni A, Fall M, Tran A, Gimonneau G. Ecological distribution and population dynamics of Rift Valley fever virus mosquito vectors (Diptera, Culicidae) in Senegal. Parasit Vectors 2018; 11:27. [PMID: 29316967 PMCID: PMC5759860 DOI: 10.1186/s13071-017-2591-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/13/2017] [Indexed: 11/17/2022] Open
Abstract
Background Many zoonotic infectious diseases have emerged and re-emerged over the last two decades. There has been a significant increase in vector-borne diseases due to climate variations that lead to environmental changes favoring the development and adaptation of vectors. This study was carried out to improve knowledge of the ecology of mosquito vectors involved in the transmission of Rift Valley fever virus (RVFV) in Senegal. Methods An entomological survey was conducted in three Senegalese agro-systems, Senegal River Delta (SRD), Senegal River Valley (SRV) and Ferlo, during the rainy season (July to November) of 2014 and 2015. Mosquitoes were trapped using CDC light traps set at ten sites for two consecutive nights during each month of the rainy season, for a total of 200 night-traps. Ecological indices were calculated to characterize the different populations of RVFV mosquito vectors. Generalized linear models with mixed effects were used to assess the influence of climatic conditions on the abundance of RVFV mosquito vectors. Results A total of 355,408 mosquitoes belonging to 7 genera and 35 species were captured in 200 night-traps. RVFV vectors represented 89.02% of the total, broken down as follows: Ae. vexans arabiensis (31.29%), Cx. poicilipes (0.6%), Cx. tritaeniorhynchus (33.09%) and Ma. uniformis (24.04%). Comparison of meteorological indices (rainfall, temperature, relative humidity), abundances and species diversity indicated that there were no significant differences between SRD and SRV (P = 0.36) while Ferlo showed significant differences with both (P < 0.001). Mosquito collection increased significantly with temperature for Ae. vexans arabiensis (P < 0.001), Cx. tritaeniorhynchus (P = 0.04) and Ma. uniformis (P = 0.01), while Cx. poicilipes decreased (P = 0.003). Relative humidity was positively and significantly associated with the abundances of Ae. vexans arabiensis (P < 0.001), Cx. poicilipes (P = 0.01) and Cx. tritaeniorhynchus (P = 0.007). Rainfall had a positive and significant effect on the abundances of Ae. vexans arabiensis (P = 0.005). The type of biotope (temporary ponds, river or lake) around the trap points had a significant effect on the mosquito abundances (P < 0.001). Conclusions In terms of species diversity, the SRD and SRV ecosystems are similar to each other and different from that of Ferlo. Meteorological indices and the type of biotope (river, lake or temporary pond) have significant effects on the abundance of RVFV mosquito vectors. Electronic supplementary material The online version of this article (10.1186/s13071-017-2591-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Biram Biteye
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal. .,Université Cheikh Anta Diop, Faculté des Sciences et Techniques, Département de Biologie Animale, Laboratoire d'Ecologie Vectorielle et Parasitaire, Dakar, Senegal.
| | - Assane G Fall
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal
| | - Mamadou Ciss
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal
| | - Momar T Seck
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal
| | - Andrea Apolloni
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal.,CIRAD, UMR ASTRE, INRA, F-34398, Montpellier, France
| | - Moussa Fall
- Institut Sénégalais de Recherches Agricoles/Laboratoire National de l'Elevage et de Recherches Vétérinaires, BP 2057, Dakar-Hann, Senegal.,Université Cheikh Anta Diop, Faculté des Sciences et Techniques, Département de Biologie Animale, Laboratoire d'Ecologie Vectorielle et Parasitaire, Dakar, Senegal
| | - Annelise Tran
- CIRAD, UMR ASTRE, INRA, F-34398, Montpellier, France.,CIRAD, UMR TETIS, F-97940, Sainte-Clotilde, Reunion Island, France
| | - Geoffrey Gimonneau
- CIRAD, UMR INTERTRYP, F-34398, Montpellier, France.,Centre International de Recherche - Développement sur l'Elevage en zone subhumide, Bobo-Dioulasso 01, BP 454, Burkina Faso
| |
Collapse
|
29
|
Overlapping CD8+ and CD4+ T-cell epitopes identification for the progression of epitope-based peptide vaccine from nucleocapsid and glycoprotein of emerging Rift Valley fever virus using immunoinformatics approach. INFECTION GENETICS AND EVOLUTION 2017; 56:75-91. [PMID: 29107145 PMCID: PMC7106247 DOI: 10.1016/j.meegid.2017.10.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 10/02/2017] [Accepted: 10/25/2017] [Indexed: 12/19/2022]
Abstract
Rift Valley fever virus (RVFV) is an emergent arthropod-borne zoonotic infectious viral pathogen which causes fatal diseases in the humans and ruminants. Currently, no effective and licensed vaccine is available for the prevention of RVFV infection in endemic as well as in non-endemic regions. So, an immunoinformatics-driven genome-wide screening approach was performed for the identification of overlapping CD8+ and CD4+ T-cell epitopes and also linear B-cell epitopes from the conserved sequences of the nucleocapsid (N) and glycoprotein (G) of RVFV. We identified overlapping 99.39% conserved 1 CD8+ T-cell epitope (MMHPSFAGM) from N protein and 100% conserved 7 epitopes (AVFALAPVV, LAVFALAPV, FALAPVVFA, VFALAPVVF, IAMTVLPAL, FFDWFSGLM, and FLLIYLGRT) from G protein and also identified IL-4 and IFN-γ induced (99.39% conserved) 1 N protein CD4+ T-cell epitope (HMMHPSFAGMVDPSL) and 100% conserved 5 G protein CD4+ T-cell epitopes (LPALAVFALAPVVFA, PALAVFALAPVVFAE, GIAMTVLPALAVFAL, GSWNFFDWFSGLMSW, and FFLLIYLGRTGLSKM). The overlapping CD8+ and CD4+ T-cell epitopes were bound with most conserved HLA-C*12:03 and HLA-DRB1*01:01, respectively with the high binding affinity (kcal/mol). The combined population coverage analysis revealed that the allele frequencies of these epitopes are high in endemic and non-endemic regions. Besides, we found 100% conserved and non-allergenic 2 decamer B-cell epitopes, GVCEVGVQAL and RVFNCIDWVH of G protein had the sequence similarity with the nonamer CD8+ T-cell epitopes, VCEVGVQAL and RVFNCIDWV, respectively. Consequently, these epitopes may be used for the development of epitope-based peptide vaccine against emerging RVFV. However, in vivo and in vitro experiments are required for their efficient use as a vaccine.
Collapse
|
30
|
Current Status of Rift Valley Fever Vaccine Development. Vaccines (Basel) 2017; 5:vaccines5030029. [PMID: 28925970 PMCID: PMC5620560 DOI: 10.3390/vaccines5030029] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/16/2017] [Accepted: 09/18/2017] [Indexed: 01/08/2023] Open
Abstract
Rift Valley Fever (RVF) is a mosquito-borne zoonotic disease that presents a substantial threat to human and public health. It is caused by Rift Valley fever phlebovirus (RVFV), which belongs to the genus Phlebovirus and the family Phenuiviridae within the order Bunyavirales. The wide distribution of competent vectors in non-endemic areas coupled with global climate change poses a significant threat of the transboundary spread of RVFV. In the last decade, an improved understanding of the molecular biology of RVFV has facilitated significant progress in the development of novel vaccines, including DIVA (differentiating infected from vaccinated animals) vaccines. Despite these advances, there is no fully licensed vaccine for veterinary or human use available in non-endemic countries, whereas in endemic countries, there is no clear policy or practice of routine/strategic livestock vaccinations as a preventive or mitigating strategy against potential RVF disease outbreaks. The purpose of this review was to provide an update on the status of RVF vaccine development and provide perspectives on the best strategies for disease control. Herein, we argue that the routine or strategic vaccination of livestock could be the best control approach for preventing the outbreak and spread of future disease.
Collapse
|
31
|
Bob NS, Bâ H, Fall G, Ishagh E, Diallo MY, Sow A, Sembene PM, Faye O, El Kouri B, Sidi ML, Sall AA. Detection of the Northeastern African Rift Valley Fever Virus Lineage During the 2015 Outbreak in Mauritania. Open Forum Infect Dis 2017. [PMID: 28638845 PMCID: PMC5473438 DOI: 10.1093/ofid/ofx087] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Background Rift Valley fever (RVF) is an acute viral anthropozoonosis that causes epizootics and epidemics among livestock population and humans. Multiple emergences and reemergences of the virus have occurred in Mauritania over the last decade. This article describes the outbreak that occurred in 2015 in Mauritania and reports the results of serological and molecular investigations of blood samples collected from suspected RVF patients. Methods An RVF outbreak was reported from 14 September to 26 November 2015 in Mauritania. Overall, 184 suspected cases from different localities were identified by 26 health facilities. Blood samples were collected and tested by enzyme-linked immunosorbent assay (ELISA) and real-time reverse-transcription polymerase chain reaction (RT-PCR) at the Institut Pasteur de Dakar (IPD). Sequencing of partial genomes and phylogenetic analyses were performed on RT-PCR–positive samples. As part of routine surveillance at IPD, samples were also screened for dengue, yellow fever, West Nile, Crimean Congo hemorrhagic fever, Zika, and Chikungunya viruses by ELISA and RT-PCR. Results Of the 184 suspected cases, there were 57 confirmed cases and 12 deaths. Phylogenetic analysis of the sequences indicated an emergence of a virus that originated from Northeastern Africa. Our results show co-circulation of other arboviruses in Mauritania—dengue, Crimean Congo hemorrhagic fever, and West Nile viruses. Conclusion The Northeastern Africa lineage of RVF was responsible for the outbreak in Mauritania in 2015. Co-circulation of multiples arboviruses was detected. This calls for systematic differential diagnosis and highlights the need to strengthen arbovirus surveillance in Africa.
Collapse
Affiliation(s)
- Ndeye Sakha Bob
- Pole of Virology, Arbovirus and Viral Hemorrhagic Fevers Unit, Pasteur Institute of Dakar, Senegal
| | - Hampâté Bâ
- Viral Hemorrhagic Fevers Diagnostics Unit, National Institute of Public Health Research, Nouakchott, Mauritania
| | - Gamou Fall
- Pole of Virology, Arbovirus and Viral Hemorrhagic Fevers Unit, Pasteur Institute of Dakar, Senegal
| | - Elkhalil Ishagh
- Department of Epidemiological Surveillance, Ministry of Health, Islamic Republic of Mauritania, Nouakchott
| | - Mamadou Y Diallo
- Health Securities and Emergency, World Health Organization,Mauritania
| | - Abdourahmane Sow
- Pole of Virology, Arbovirus and Viral Hemorrhagic Fevers Unit, Pasteur Institute of Dakar, Senegal.,West African Health Organization, Ouagadougou, Burkina Fasso
| | | | - Ousmane Faye
- Pole of Virology, Arbovirus and Viral Hemorrhagic Fevers Unit, Pasteur Institute of Dakar, Senegal
| | - Brahim El Kouri
- Viral Hemorrhagic Fevers Diagnostics Unit, National Institute of Public Health Research, Nouakchott, Mauritania
| | - Mohamed Lemine Sidi
- Direction of Diseases Control, Ministry of Health, Islamic Republic of Mauritania, Nouakchott
| | - Amadou Alpha Sall
- Pole of Virology, Arbovirus and Viral Hemorrhagic Fevers Unit, Pasteur Institute of Dakar, Senegal
| |
Collapse
|
32
|
Pedro SA, Abelman S, Tonnang HEZ. Predicting Rift Valley Fever Inter-epidemic Activities and Outbreak Patterns: Insights from a Stochastic Host-Vector Model. PLoS Negl Trop Dis 2016; 10:e0005167. [PMID: 28002417 PMCID: PMC5176166 DOI: 10.1371/journal.pntd.0005167] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/06/2016] [Indexed: 11/19/2022] Open
Abstract
Rift Valley fever (RVF) outbreaks are recurrent, occurring at irregular intervals of up to 15 years at least in East Africa. Between outbreaks disease inter-epidemic activities exist and occur at low levels and are maintained by female Aedes mcintoshi mosquitoes which transmit the virus to their eggs leading to disease persistence during unfavourable seasons. Here we formulate and analyse a full stochastic host-vector model with two routes of transmission: vertical and horizontal. By applying branching process theory we establish novel relationships between the basic reproduction number, R0, vertical transmission and the invasion and extinction probabilities. Optimum climatic conditions and presence of mosquitoes have not fully explained the irregular oscillatory behaviour of RVF outbreaks. Using our model without seasonality and applying van Kampen system-size expansion techniques, we provide an analytical expression for the spectrum of stochastic fluctuations, revealing how outbreaks multi-year periodicity varies with the vertical transmission. Our theory predicts complex fluctuations with a dominant period of 1 to 10 years which essentially depends on the efficiency of vertical transmission. Our predictions are then compared to temporal patterns of disease outbreaks in Tanzania, Kenya and South Africa. Our analyses show that interaction between nonlinearity, stochasticity and vertical transmission provides a simple but plausible explanation for the irregular oscillatory nature of RVF outbreaks. Therefore, we argue that while rainfall might be the major determinant for the onset and switch-off of an outbreak, the occurrence of a particular outbreak is also a result of a build up phenomena that is correlated to vertical transmission efficiency.
Collapse
Affiliation(s)
- Sansao A. Pedro
- School of Computer Science and Applied Mathematics, University of the Witwatersrand, Johannesburg, South Africa
- Modelling Unit, International Center of Insect Physiology and Ecology, Nairobi, Kenya
- Departmento de Matemática e Informática, Universidade Eduardo Mondlane, Maputo, Mozambique
| | - Shirley Abelman
- School of Computer Science and Applied Mathematics, University of the Witwatersrand, Johannesburg, South Africa
| | - Henri E. Z. Tonnang
- International Maize and Wheat Improvement Center (CIMMYT) ICRAF House, United Nation, Avenue, Gigiri, Nairobi, Kenya
| |
Collapse
|