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Kimble JB, Noronha L, Trujillo JD, Mitzel D, Richt JA, Wilson WC. Rift Valley Fever. Vet Clin North Am Food Anim Pract 2024; 40:293-304. [PMID: 38453549 DOI: 10.1016/j.cvfa.2024.01.004] [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] [Indexed: 03/09/2024] Open
Abstract
Rift Valley fever (RVF) is a zoonotic viral disease that affects domestic and wild ruminants such as cattle, sheep, goats, camels, and buffaloes. Rift valley fever virus (RVFV), the causative agent of RVF, can also infect humans. RVFV is an arthropod-borne virus (arbovirus) that is primarily spread through the bites of infected mosquitoes or exposure to infected blood. RVFV was first isolated and characterized in the Rift Valley of Kenya in 1931 and is endemic throughout sub-Saharan Africa, including Comoros and Madagascar, the Arabian Peninsula (Saudi Arabia and Yemen), and Mayotte.
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Affiliation(s)
- J Brian Kimble
- Foreign Arthropod-Borne Animal Diseases Research Unit, National Bio and Agro-Defense Facility, USDA, ARS, Manhattan, KS, USA
| | - Leela Noronha
- Foreign Arthropod-Borne Animal Diseases Research Unit, National Bio and Agro-Defense Facility, USDA, ARS, Manhattan, KS, USA
| | - Jessie D Trujillo
- Diganostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Dana Mitzel
- Foreign Arthropod-Borne Animal Diseases Research Unit, National Bio and Agro-Defense Facility, USDA, ARS, Manhattan, KS, USA
| | - Juergen A Richt
- Diganostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - William C Wilson
- Foreign Arthropod-Borne Animal Diseases Research Unit, National Bio and Agro-Defense Facility, USDA, ARS, Manhattan, KS, USA.
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Situma S, Nyakarahuka L, Omondi E, Mureithi M, Mweu MM, Muturi M, Mwatondo A, Dawa J, Konongoi L, Khamadi S, Clancey E, Lofgren E, Osoro E, Ngere I, Breiman RF, Bakamutumaho B, Muruta A, Gachohi J, Oyola SO, Njenga MK, Singh D. Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa. BMJ Glob Health 2024; 9:e014737. [PMID: 38857944 PMCID: PMC11168176 DOI: 10.1136/bmjgh-2023-014737] [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: 12/03/2023] [Accepted: 05/25/2024] [Indexed: 06/12/2024] Open
Abstract
BACKGROUND Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterising recent RVF disease events in East Africa. METHODS Data on 100 disease events (2008-2022) from Kenya, Uganda and Tanzania were obtained from public databases and institutions, and modelled against possible geoecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalised difference vegetation index (NDVI), livestock production system, land-use change and long-term climatic variations. Decadal climatic variations between 1980 and 2022 were evaluated for association with the changing disease pattern. RESULTS Of 100 events, 91% were small RVF clusters with a median of one human (IQR, 1-3) and three livestock cases (IQR, 2-7). These clusters exhibited minimal human mortality (IQR, 0-1), and occurred primarily in highlands (67%), with 35% reported in areas that had never reported RVF disease. Multivariate regression analysis of geoecological variables showed a positive correlation between occurrence and increasing temperature and rainfall. A 1°C increase in temperature and a 1-unit increase in NDVI, one months prior were associated with increased RVF incidence rate ratios of 1.20 (95% CI 1.1, 1.2) and 1.93 (95% CI 1.01, 3.71), respectively. Long-term climatic trends showed a significant decadal increase in annual mean temperature (0.12-0.3°C/decade, p<0.05), associated with decreasing rainfall in arid and semi-arid lowlands but increasing rainfall trends in highlands (p<0.05). These hotter and wetter highlands showed increasing frequency of RVF clusters, accounting for 76% and 43% in Uganda and Kenya, respectively. CONCLUSION These findings demonstrate the changing epidemiology of RVF disease. The widening geographic range of disease is associated with climatic variations, with the likely impact of wider dispersal of virus to new areas of endemicity and future epidemics.
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Affiliation(s)
- Silvia Situma
- Washington State University Global Health Program-Kenya, Nairobi, Kenya
- University of Nairobi, Faculty of Health Sciences, Nairobi, Kenya
- Department of Animal Science, Pwani University, Kilifi, Kenya
| | - Luke Nyakarahuka
- Uganda Virus Research Institute, Entebbe, Uganda
- Emory University, Atlanta, Georgia, USA
- Department of Biosecurity, Ecosystems and Veterinary Public Health, Makerere University, Kampala, Uganda
| | - Evans Omondi
- African Population and Health Research Center, Nairobi, Kenya
- Strathmore University, Nairobi, Kenya
| | | | | | | | | | - Jeanette Dawa
- Washington State University Global Health Program-Kenya, Nairobi, Kenya
| | | | | | - Erin Clancey
- Washington State University, Pullman, Washington, USA
| | - Eric Lofgren
- Washington State University, Pullman, Washington, USA
| | - Eric Osoro
- Washington State University Global Health Program-Kenya, Nairobi, Kenya
| | - Isaac Ngere
- Washington State University Global Health Program-Kenya, Nairobi, Kenya
| | | | | | | | - John Gachohi
- Washington State University Global Health Program-Kenya, Nairobi, Kenya
| | - Samuel O Oyola
- International Livestock Research Institute, Nairobi, Kenya
| | - M Kariuki Njenga
- Washington State University Global Health Program-Kenya, Nairobi, Kenya
- Washington State University, Pullman, Washington, USA
| | - Deepti Singh
- Washington State University, Pullman, Washington, USA
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Gerken KN, Owuor KO, Ndenga B, Wambua S, Winter C, Chemutai S, Omukuti R, Arabu D, Miring’u I, Wilson WC, Mutuku F, Waggoner JJ, Pinsky B, Bosire C, LaBeaud AD. Expanding Understanding of Urban Rift Valley Fever Risk and Associated Vector Ecology at Slaughterhouses in Kisumu, Kenya. Pathogens 2024; 13:488. [PMID: 38921786 PMCID: PMC11206928 DOI: 10.3390/pathogens13060488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/01/2024] [Accepted: 06/04/2024] [Indexed: 06/27/2024] Open
Abstract
Rift Valley fever virus (RVFV) is an adaptable arbovirus that can be transmitted by a wide variety of arthropods. Widespread urban transmission of RVFV has not yet occurred, but peri-urban outbreaks of RVFV have recently been documented in East Africa. We previously reported low-level exposure in urban communities and highlighted the risk of introduction via live animal influx. We deployed a slaughtered animal testing framework in response to an early warning system at two urban slaughterhouses and tested animals entering the meat value chain for anti-RVFV IgG and IgM antibodies. We simultaneously trapped mosquitoes for RVFV and bloodmeal testing. Out of 923 animals tested, an 8.5% IgG seroprevalence was identified but no evidence of recent livestock exposure was detected. Mosquito species abundance varied greatly by slaughterhouse site, which explained 52% of the variance in blood meals. We captured many Culex spp., a known RVFV amplifying vector, at one of the sites (p < 0.001), and this species had the most diverse blood meals. No mosquito pools tested positive for RVFV antigen using a rapid VecTOR test. These results expand understanding of potential RVF urban disease ecology, and highlight that slaughterhouses are key locations for future surveillance, modelling, and monitoring efforts.
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Affiliation(s)
- Keli Nicole Gerken
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA 94305, USA; (B.P.); (A.D.L.)
| | - Kevin Omondi Owuor
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu 40100, Kenya; (K.O.O.); (B.N.); (C.W.)
| | - Bryson Ndenga
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu 40100, Kenya; (K.O.O.); (B.N.); (C.W.)
| | - Sammy Wambua
- Pwani University Biosciences Research Centre (PUBReC), Pwani University, Kilifi 80108, Kenya; (S.W.); (S.C.); (R.O.); (D.A.); (I.M.)
- Research and Conservation Support Society (RECOURSE), Kilifi 80108, Kenya
- School of Biodiversity One Health and Veterinary Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Christabel Winter
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu 40100, Kenya; (K.O.O.); (B.N.); (C.W.)
| | - Salome Chemutai
- Pwani University Biosciences Research Centre (PUBReC), Pwani University, Kilifi 80108, Kenya; (S.W.); (S.C.); (R.O.); (D.A.); (I.M.)
- Research and Conservation Support Society (RECOURSE), Kilifi 80108, Kenya
| | - Rodney Omukuti
- Pwani University Biosciences Research Centre (PUBReC), Pwani University, Kilifi 80108, Kenya; (S.W.); (S.C.); (R.O.); (D.A.); (I.M.)
- Research and Conservation Support Society (RECOURSE), Kilifi 80108, Kenya
| | - Daniel Arabu
- Pwani University Biosciences Research Centre (PUBReC), Pwani University, Kilifi 80108, Kenya; (S.W.); (S.C.); (R.O.); (D.A.); (I.M.)
- Research and Conservation Support Society (RECOURSE), Kilifi 80108, Kenya
| | - Irene Miring’u
- Pwani University Biosciences Research Centre (PUBReC), Pwani University, Kilifi 80108, Kenya; (S.W.); (S.C.); (R.O.); (D.A.); (I.M.)
- Research and Conservation Support Society (RECOURSE), Kilifi 80108, Kenya
| | - William C. Wilson
- Foreign Arthropod-Borne Animal Disease Research, United States Department of Agriculture-Agriculture Research Service (USDA-ARS), Manhattan, KS 66502, USA;
| | - Francis Mutuku
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa 80110, Kenya;
| | - Jesse J. Waggoner
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Benjamin Pinsky
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA 94305, USA; (B.P.); (A.D.L.)
| | - Carren Bosire
- Department of Pure and Applied Sciences, Technical University of Mombasa, Mombasa 80100, Kenya;
| | - Angelle Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA 94305, USA; (B.P.); (A.D.L.)
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Situma S, Nyakarahuka L, Omondi E, Mureithi M, Mweu M, Muturi M, Mwatondo A, Dawa J, Konongoi L, Khamadi S, Clancey E, Lofgren E, Osoro E, Ngere I, Breiman RF, Bakamutumaho B, Muruta A, Gachohi J, Oyola SO, Njenga MK, Singh D. Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.17.24307534. [PMID: 38798521 PMCID: PMC11118650 DOI: 10.1101/2024.05.17.24307534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Background Recent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease. We investigated factors associated with the phenomenon by characterizing recent RVF disease events in East Africa. Methods Data on 100 disease events (2008 - 2022) from Kenya, Uganda, and Tanzania were obtained from public databases and institutions, and modeled against possible geo-ecological risk factors of occurrence including altitude, soil type, rainfall/precipitation, temperature, normalized difference vegetation index (NDVI), livestock production system, land-use change, and long-term climatic variations. Decadal climatic variations between 1980-2022 were evaluated for association with the changing disease pattern. Results Of 100 events, 91% were small RVF clusters with a median of one human (IQR, 1-3) and 3 livestock cases (IQR, 2-7). These clusters exhibited minimal human mortality (IQR 0-1), and occurred primarily in highlands (67%), with 35% reported in areas that had never reported RVF disease. Multivariate regression analysis of geo-ecological variables showed a positive correlation between occurrence and increasing temperature and rainfall. A 1oC increase in temperature and 1-unit increase in NDVI, 1-3 months prior were associated with increased RVF incidence rate ratios (IRR) of 1.20 (95% CI 1.1,1.2) and 9.88 (95% CI 0.85, 119.52), respectively. Long-term climatic trends showed significant decadal increase in annual mean temperature (0.12 to 0.3oC/decade, P<0.05), associated with decreasing rainfall in arid and semi-arid lowlands but increasing rainfall trends in highlands (P<0.05). These hotter and wetter highlands showed increasing frequency of RVF clusters, accounting for 76% and 43% in Uganda and Kenya, respectively. Conclusion These findings demonstrate the changing epidemiology of RVF disease. The widening geographic range of disease is associated with climatic variations, with the likely impact of wider dispersal of virus to new areas of endemicity and future epidemics. Key questions What is already known on this topic?: Rift Valley fever is recognized for its association with heavy rainfall, flooding, and El Niño rains in the East African region. A growing body of recent studies has highlighted a shifting landscape of the disease, marked by an expanding geographic range and an increasing number of small RVF clusters.What this study adds: This study challenges previous beliefs about RVF, revealing that it predominantly occurs in small clusters rather than large outbreaks, and its association with El Niño is not as pronounced as previously thought. Over 65% of these clusters are concentrated in the highlands of Kenya and Uganda, with 35% occurring in previously unaffected regions, accompanied by an increase in temperature and total rainfall between 1980 and 2022, along with a rise in the annual number of rainy days. Notably, the observed rainfall increases are particularly significant during the short-rains season (October-December), aligning with a secondary peak in RVF incidence. In contrast, the lowlands of East Africa, where typical RVF epidemics occur, display smaller and more varied trends in annual rainfall.How this study might affect research, practice, or policy: The worldwide consequence of the expanding RVF cluster is the broader dispersion of the virus, leading to the establishment of new regions with virus endemicity. This escalation heightens the risk of more extensive extreme-weather-associated RVF epidemics in the future. Global public health institutions must persist in developing preparedness and response strategies for such scenarios. This involves the creation and approval of human RVF vaccines and therapeutics, coupled with a rapid distribution plan through regional banks.
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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.
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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.
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Lehmann T, Kouam C, Woo J, Diallo M, Wilkerson R, Linton YM. The African mosquito-borne diseasosome: geographical patterns, range expansion and future disease emergence. Proc Biol Sci 2023; 290:20231581. [PMID: 38018102 PMCID: PMC10685135 DOI: 10.1098/rspb.2023.1581] [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: 08/21/2023] [Accepted: 10/25/2023] [Indexed: 11/30/2023] Open
Abstract
Mosquito-borne diseases (MBDs) threaten public health and food security globally. We provide the first biogeographic description of the African mosquito fauna (677 species) and the 151 mosquito-borne pathogens (MBPs) they transmit. While mosquito species richness agrees with expectations based on Africa's land surface, African arboviruses and mammalian plasmodia are more speciose than expected. Species assemblages of mosquitoes and MBPs similarly separate sub-Saharan Africa from North Africa, and those in West and Central Africa from eastern and southern Africa. Similarities between mosquitoes and MBPs in diversity and range size suggest that mosquitoes are key in delimiting the range of MBPs. With approximately 25% endemicity, approximately 50% occupying one to three countries and less than 5% occupying greater than 25 countries, the ranges of mosquitoes and MBPs are surprisingly small, suggesting that most MBPs are transmitted by a single mosquito species. Exceptionally widespread mosquito species feed on people and livestock, and most are high-altitude-windborne migrants. Likewise, widespread MBPs are transmitted among people or livestock by widespread mosquitoes, suggesting that adapting to people or livestock and to widespread mosquito species promote range expansion in MBPs. Range size may predict range expansion and emergence risk. We highlight key knowledge gaps that impede prediction and mitigation of future emergence of local and global MBDs.
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Affiliation(s)
- Tovi Lehmann
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Cedric Kouam
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Joshua Woo
- Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Mawlouth Diallo
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, Dakar, Senegal
| | - Richard Wilkerson
- Walter Reed Biosystematics Unit (WRBU), Smithsonian Institution Museum Support Center, Suitland, MD, USA
- Department of Entomology, Smithsonian Institution–National Museum of Natural History, Washington, DC, USA
| | - Yvonne-Marie Linton
- Walter Reed Biosystematics Unit (WRBU), Smithsonian Institution Museum Support Center, Suitland, MD, USA
- Department of Entomology, Smithsonian Institution–National Museum of Natural History, Washington, DC, USA
- One Health Branch, Walter Reed Army Institute of Research (WRAIR), Silver Spring, MD, USA
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Smith CB, Hodges NF, Kading RC, Campbell CL. Dishevelled Has Anti-Viral Activity in Rift Valley Fever Virus Infected Aedes aegypti. Viruses 2023; 15:2140. [PMID: 38005818 PMCID: PMC10675198 DOI: 10.3390/v15112140] [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: 04/18/2023] [Revised: 10/17/2023] [Accepted: 10/19/2023] [Indexed: 11/26/2023] Open
Abstract
Mosquitoes in the genera Aedes and Culex are vectors of Rift Valley fever virus (RVFV), which emerges in periodic epidemics in Africa and Saudi Arabia. Factors that influence the transmission dynamics of RVFV are not well characterized. To address this, we interrogated mosquito host-signaling responses through analysis of differentially expressed genes (DEGs) in two mosquito species with marked differences in RVFV vector competence: Aedes aegypti (Aae, low competence) and Culex tarsalis (Cxt, high competence). Mosquito-host transcripts related to three different signaling pathways were investigated. Selected genes from the Wingless (Wg, WNT-beta-catenin) pathway, which is a conserved regulator of cell proliferation and differentiation, were assessed. One of these, dishevelled (DSH), differentially regulates progression/inhibition of the WNT and JNK (c-Jun N-terminal Kinase) pathways. A negative regulator of the JNK-signaling pathway, puckered, was also assessed. Lastly, Janus kinase/signal transducers and activators of transcription (JAK-STAT) are important for innate immunity; in this context, we tested domeless levels. Here, individual Aae and Cxt were exposed to RVFV MP-12 via oral bloodmeals and held for 14 days. Robust decreases in DEGs in both Aae and Cxt were observed. In particular, Aae DSH expression, but not Cxt DSH, was correlated to the presence/absence of viral RNA at 14 days post-challenge (dpc). Moreover, there was an inverse relationship between the viral copy number and aaeDSH expression. DSH silencing resulted in increased viral copy numbers compared to controls at 3 dpc, consistent with a role for aaeDSH in antiviral immunity. Analysis of cis-regulatory regions for the genes of interest revealed clues to upstream regulation of these pathways.
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Affiliation(s)
| | | | | | - Corey L. Campbell
- Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA; (C.B.S.); (R.C.K.)
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Hernandez-Valencia JC, Muñoz-Laiton P, Gómez GF, Correa MM. A Systematic Review on the Viruses of Anopheles Mosquitoes: The Potential Importance for Public Health. Trop Med Infect Dis 2023; 8:459. [PMID: 37888587 PMCID: PMC10610971 DOI: 10.3390/tropicalmed8100459] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023] Open
Abstract
Anopheles mosquitoes are the vectors of Plasmodium, the etiological agent of malaria. In addition, Anopheles funestus and Anopheles gambiae are the main vectors of the O'nyong-nyong virus. However, research on the viruses carried by Anopheles is scarce; thus, the possible transmission of viruses by Anopheles is still unexplored. This systematic review was carried out to identify studies that report viruses in natural populations of Anopheles or virus infection and transmission in laboratory-reared mosquitoes. The databases reviewed were EBSCO-Host, Google Scholar, Science Direct, Scopus and PubMed. After the identification and screening of candidate articles, a total of 203 original studies were included that reported on a variety of viruses detected in Anopheles natural populations. In total, 161 viruses in 54 species from 41 countries worldwide were registered. In laboratory studies, 28 viruses in 15 Anopheles species were evaluated for mosquito viral transmission capacity or viral infection. The viruses reported in Anopheles encompassed 25 viral families and included arboviruses, probable arboviruses and Insect-Specific Viruses (ISVs). Insights after performing this review include the need for (1) a better understanding of Anopheles-viral interactions, (2) characterizing the Anopheles virome-considering the public health importance of the viruses potentially transmitted by Anopheles and the significance of finding viruses with biological control activity-and (3) performing virological surveillance in natural populations of Anopheles, especially in the current context of environmental modifications that may potentiate the expansion of the Anopheles species distribution.
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Affiliation(s)
- Juan C. Hernandez-Valencia
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
| | - Paola Muñoz-Laiton
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
| | - Giovan F. Gómez
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
- Dirección Académica, Escuela de Pregrados, Universidad Nacional de Colombia, Sede de La Paz, La Paz 202017, Colombia
| | - Margarita M. Correa
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
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Nyakarahuka L, Kyondo J, Telford C, Whitesell A, Tumusiime A, Mulei S, Baluku J, Cossaboom CM, Cannon DL, Montgomery JM, Lutwama JJ, Nichol ST, Balinandi S, Klena JD, Shoemaker TR. A Countrywide Seroepidemiological Survey of Rift Valley Fever in Livestock, Uganda, 2017. Am J Trop Med Hyg 2023; 109:548-553. [PMID: 37524326 PMCID: PMC10484263 DOI: 10.4269/ajtmh.22-0504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 05/01/2023] [Indexed: 08/02/2023] Open
Abstract
In 2016, an outbreak of Rift Valley fever was reported in the Kabale District in Uganda for the first time in 48 years. Three human cases were confirmed by polymerase chain reaction, and subsequent serological investigations revealed an overall IgG seropositivity of 13% in humans and 13% in animals. In response to this reemergence, we designed a countrywide survey to determine the seropositivity of anti-Rift Valley fever virus (RVFV) IgG antibodies in livestock. Samples were collected from 27 districts and tested for RVFV anti-IgG antibodies. A total of 3,181 livestock samples were tested, of which 54.4% were cattle (1,732 of 3,181), 34.3% were goats (1,091 of 3,181), and 11.3% were sheep (358 of 3,181). Overall RVFV seropositivity was 6.9% (221 of 3,181). Seroprevalence was greater in cattle (10.7%) compared with goats (2.6%) and sheep (2.0%), among females (7.5%) compared with males (5.2%), and among adults (7.6%) compared with juveniles (4.9%) and nurslings (6.4%). Exotic breeds and animals with a history of abortion or stillbirth also had greater odds of RVFV seropositivity. Animals grazed under tethering and paddocking had greater RVFV seropositivity compared with animals that grazed communally, and livestock in the western and eastern regions had the greatest seroprevalence. In a multivariate regression model, animal species (odds ratio [OR], 6.4; 95% CI, 3.5-11.4) and age (OR, 2.3; 95% CI, 1.4-3.6) were associated significantly with RVFV seropositivity. This study could be important in developing risk-based surveillance for early outbreak detection to limit the spread of RVFV in both human and animal populations.
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Affiliation(s)
- Luke Nyakarahuka
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
- Department of Biosecurity, Ecosystems and Veterinary Public Health, Makerere University, Kampala, Uganda
| | - Jackson Kyondo
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Carson Telford
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Amy Whitesell
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Alex Tumusiime
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Sophia Mulei
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Jimmy Baluku
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Caitlin M. Cossaboom
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Deborah L. Cannon
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Joel M. Montgomery
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Julius J. Lutwama
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Stuart T. Nichol
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Stephen Balinandi
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - John D. Klena
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Trevor R. Shoemaker
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, US Centers for Disease Control and Prevention, Atlanta, Georgia
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10
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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.
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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
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11
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Balaraman V, Gaudreault NN, Trujillo JD, Indran SV, Wilson WC, Richt JA. RT-qPCR genotyping assays for differentiating Rift Valley fever phlebovirus strains. J Virol Methods 2023; 315:114693. [PMID: 36801236 PMCID: PMC10040438 DOI: 10.1016/j.jviromet.2023.114693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023]
Abstract
Rift Valley fever phlebovirus (RVFV) is an emerging, mosquito-borne, zoonotic pathogen. Real time RT-qPCR genotyping (GT) assays were developed to differentiate between two RVFV wild-type strains (128B-15 and SA01-1322) and a vaccine strain (MP-12). The GT assay uses a one-step RT-qPCR mix, with two different RVFV strain-specific primers (either forward or reverse) with long or short G/C tags and a common primer (either forward or reverse) for each of the 3 genomic segments. The GT assay produces PCR amplicons with unique melting temperatures that are resolved in a post PCR melt curve analysis for strain identification. Furthermore, a strain specific RT-qPCR (SS-PCR) assay was developed to allow for specific detection of low titer RVFV strains in mixed RVFV samples. Our data shows that the GT assays are capable of differentiating L, M, and S segments of RVFV strains 128B-15 versus MP-12, and 128B-15 versus SA01-1322. The SS-PCR assay results revealed that it can specifically amplify and detect a low titer MP-12 strain in mixed RVFV samples. Overall, these two novel assays are useful as screening tools for determining reassortment of the segmented RVFV genome during co-infections, and could be adapted and applied for other segmented pathogens of interest.
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Affiliation(s)
- Velmurugan Balaraman
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Natasha N Gaudreault
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Jessie D Trujillo
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Sabarish V Indran
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - William C Wilson
- National Bio and Agro-Defense Facility, United States Department of Agriculture, Agricultural Research Service, Foreign Arthropod-Borne Animal Diseases Research Unit, Manhattan, KS, United States
| | - Juergen A Richt
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States.
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12
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Using Multiplex Amplicon PCR Technology to Efficiently and Timely Generate Rift Valley Fever Virus Sequence Data for Genomic Surveillance. Viruses 2023; 15:v15020477. [PMID: 36851690 PMCID: PMC9961268 DOI: 10.3390/v15020477] [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: 01/12/2023] [Revised: 02/04/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023] Open
Abstract
Rift Valley fever (RVF) is a febrile vector-borne disease endemic in Africa and continues to spread in new territories. It is a climate-sensitive disease mostly triggered by abnormal rainfall patterns. The disease is associated with high mortality and morbidity in both humans and livestock. RVF is caused by the Rift Valley fever virus (RVFV) of the genus Phlebovirus in the family Phenuiviridae. It is a tripartite RNA virus with three genomic segments: small (S), medium (M) and large (L). Pathogen genomic sequencing is becoming a routine procedure and a powerful tool for understanding the evolutionary dynamics of infectious organisms, including viruses. Inspired by the utility of amplicon-based sequencing demonstrated in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and Ebola, Zika and West Nile viruses, we report an RVFV sample preparation based on amplicon multiplex polymerase chain reaction (amPCR) for template enrichment and reduction of background host contamination. The technology can be implemented rapidly to characterize and genotype RVFV during outbreaks in a near-real-time manner. To achieve this, we designed 74 multiplex primer sets covering the entire RVFV genome to specifically amplify the nucleic acid of RVFV in clinical samples from an animal tissue. Using this approach, we demonstrate achieving complete RVFV genome coverage even from samples containing a relatively low viral load. We report the first primer scheme approach of generating multiplex primer sets for a tripartite virus which can be replicated for other segmented viruses.
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13
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Ogola EO, Kopp A, Bastos ADS, Slothouwer I, Omoga DCA, Osalla J, Sang R, Torto B, Junglen S, Tchouassi DP. Phlebovirus diversity in ticks from livestock in arid ecologies in Kenya. Ticks Tick Borne Dis 2023; 14:102087. [PMID: 36459866 DOI: 10.1016/j.ttbdis.2022.102087] [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: 06/04/2022] [Revised: 10/11/2022] [Accepted: 11/09/2022] [Indexed: 11/21/2022]
Abstract
Phleboviruses are emerging pathogens of public health importance. However, their association with ticks is poorly described, particularly in Africa. Here, adult ticks infesting cattle, goats and sheep were collected in two dryland pastoralist ecosystems of Kenya (Baringo and Kajiado counties) and were screened for infection with phleboviruses. Ticks mainly belonged to the species Rhipicephalus appendiculatus, Hyalomma impeltatum, and Hyalomma rufipes. A fragment of the RNA-dependent RNA polymerase (RdRp) gene was identified in thirty of 671 tick pools, of which twenty-nine were from livestock sampled in Baringo county. Phylogenetic analyses revealed that twenty-five sequences were falling in three clades within the group of tick-associated phleboviruses. The sequences of the three clades showed nucleotide distances 8%, 19% and 22%, respectively, to previously known viruses suggesting that these sequence fragments may belong to three distinct viruses. Viruses of the group of tick-associated phleboviruses have been found in several countries and continents but so far have not been associated with disease in humans or animals. In addition, five sequences were found to group with the sandfly-associated phleboviruses Bogoria virus, Perkerra virus and Ntepes virus recently detected in the same region. Further studies are needed to investigate the transmission and maintenance cycles of these viruses, as well as to assess their potential to infect vertebrates.
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Affiliation(s)
- Edwin O Ogola
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya; Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Pretoria 0028, South Africa
| | - Anne Kopp
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany
| | - Armanda D S Bastos
- Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Pretoria 0028, South Africa
| | - Inga Slothouwer
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany
| | - Dorcus C A Omoga
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Josephine Osalla
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya; Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Pretoria 0028, South Africa
| | - Sandra Junglen
- Institute of Virology, Charité Universitätsmedizin Berlin, Corporate Member of Free University Berlin, Humboldt-University Berlin, and Berlin Institute of Health, Chariteplatz 1, 10117 Berlin, Germany.
| | - David P Tchouassi
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.
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14
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Claudel I, Brouazin R, Lancelot R, Gouagna LC, Dupraz M, Baldet T, Bouyer J. Optimization of adult mosquito trap settings to monitor populations of Aedes and Culex mosquitoes, vectors of arboviruses in La Reunion. Sci Rep 2022; 12:19544. [PMID: 36380224 PMCID: PMC9666360 DOI: 10.1038/s41598-022-24191-9] [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: 06/27/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Competent arbovirus vectors are found in the culicid mosquito fauna of south-west Indian Ocean (SWIO) islands. In La Reunion, Aedes albopictus and Aedes aegypti mosquitoes are known vectors of dengue and chikungunya viruses. Culex quinquefasciatus is a potential vector of Rift Valley fever and West Nile viruses. To prepare a vector-control field trial against Ae. aegypti, this study aimed at identifying the best trapping strategy to catch adult Ae. aegypti, using BG-Sentinel traps (Biogents, Germany). It was implemented in two sites in southern La Reunion. Catches of Ae. albopictus and Cx. quinquefasciatus mosquitoes were also recorded. A Latin square design was used to estimate the detection probability and the apparent daily density-according to the BG-Sentinel trapping strategy: none, carbon dioxide (CO2), a commercial attractant-BG-Lure (Biogents, Germany), or both. The use of CO2 alone was associated with a higher detection probability for Ae. aegypti and Cx. quinquefasciatus mosquitoes, as well as a large increase in their apparent density. Traps with BG-Lure-alone or in combination with CO2, did not improve the detection probability of Ae. aegypti and Cx. quinquefasciatus mosquitoes. The same result was found for male Ae. albopictus. For females, baiting BG-Sentinel traps with CO2 or BG-Lure had no significant effect. The same apparent densities were found for Ae. aegypti and Ae. albopictus mosquitoes in both study sites-where Ae. aegypti mosquitoes were found at very low densities during previous surveys.
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Affiliation(s)
- Iris Claudel
- grid.121334.60000 0001 2097 0141UMR Mivegec (Maladies Infectieuses et Vecteurs: Écologie, Génétique, Évolution et Contrôle), IRD-CNRS-Univ. Montpellier, 97410 Saint-Pierre, La Réunion France
| | - Ronan Brouazin
- grid.121334.60000 0001 2097 0141UMR Mivegec (Maladies Infectieuses et Vecteurs: Écologie, Génétique, Évolution et Contrôle), IRD-CNRS-Univ. Montpellier, 97410 Saint-Pierre, La Réunion France
| | - Renaud Lancelot
- grid.121334.60000 0001 2097 0141UMR Astre (Animals, Health, Territories, Risks, Ecosystems), Cirad, Inrae, Univ. Montpellier, 34398 Montpellier, France ,grid.8183.20000 0001 2153 9871Cirad, UMR Astre, 97491 Sainte Clotilde, La Réunion France
| | | | - Marlène Dupraz
- grid.121334.60000 0001 2097 0141UMR Astre (Animals, Health, Territories, Risks, Ecosystems), Cirad, Inrae, Univ. Montpellier, 34398 Montpellier, France ,grid.8183.20000 0001 2153 9871Cirad, UMR Astre, 97491 Sainte Clotilde, La Réunion France
| | - Thierry Baldet
- grid.121334.60000 0001 2097 0141UMR Astre (Animals, Health, Territories, Risks, Ecosystems), Cirad, Inrae, Univ. Montpellier, 34398 Montpellier, France ,grid.8183.20000 0001 2153 9871Cirad, UMR Astre, 97491 Sainte Clotilde, La Réunion France
| | - Jérémy Bouyer
- grid.121334.60000 0001 2097 0141UMR Astre (Animals, Health, Territories, Risks, Ecosystems), Cirad, Inrae, Univ. Montpellier, 34398 Montpellier, France ,grid.420221.70000 0004 0403 8399Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, IAEA Vienna, Wagramer Strasse 5, 1400 Vienna, Austria
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15
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Fang Y, Khater EIM, Xue JB, Ghallab EHS, Li YY, Jiang TG, Li SZ. Epidemiology of Mosquito-Borne Viruses in Egypt: A Systematic Review. Viruses 2022; 14:v14071577. [PMID: 35891557 PMCID: PMC9322113 DOI: 10.3390/v14071577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/12/2022] [Accepted: 07/18/2022] [Indexed: 12/21/2022] Open
Abstract
There are at least five common mosquito-borne viruses (MBVs) recorded in Egypt, including dengue virus (DENV), Rift Valley fever virus (RVFV), West Nile virus (WNV), Chikungunya virus, and Sindbis virus. Unexpected outbreaks caused by MBVs reflect the deficiencies of the MBV surveillance system in Egypt. This systematic review characterized the epidemiology of MBV prevalence in Egypt. Human, animal, and vector prevalence studies on MBVs in Egypt were retrieved from Web of Science, PubMed, and Bing Scholar, and 33 eligible studies were included for further analyses. The monophyletic characterization of the RVFV and WNV strains found in Egypt, which spans about half a century, suggests that both RVFV and WNV are widely transmitted in this nation. Moreover, the seropositive rates of DENV and WNV in hosts were on the rise in recent years, and spillover events of DENV and WNV to other countries from Egypt have been recorded. The common drawback for surveillance of MBVs in Egypt is the lack of seroprevalence studies on MBVs, especially in this century. It is necessary to evaluate endemic transmission risk, establish an early warning system for MBVs, and develop a sound joint system for medical care and public health for managing MBVs in Egypt.
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Affiliation(s)
- Yuan Fang
- NHC Key Laboratory of Parasite and Vector Biology, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai 200025, China; (Y.F.); (J.-B.X.); (Y.-Y.L.)
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
| | - Emad I. M. Khater
- Department of Entomology, Faculty of Science, Ain Shams University, Abbasiah, Cairo 11566, Egypt; (E.I.M.K.); (E.H.S.G.)
| | - Jing-Bo Xue
- NHC Key Laboratory of Parasite and Vector Biology, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai 200025, China; (Y.F.); (J.-B.X.); (Y.-Y.L.)
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
| | - Enas H. S. Ghallab
- Department of Entomology, Faculty of Science, Ain Shams University, Abbasiah, Cairo 11566, Egypt; (E.I.M.K.); (E.H.S.G.)
| | - Yuan-Yuan Li
- NHC Key Laboratory of Parasite and Vector Biology, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai 200025, China; (Y.F.); (J.-B.X.); (Y.-Y.L.)
| | - Tian-Ge Jiang
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
| | - Shi-Zhu Li
- NHC Key Laboratory of Parasite and Vector Biology, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai 200025, China; (Y.F.); (J.-B.X.); (Y.-Y.L.)
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
- Correspondence:
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16
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Abdellahoum Z, Nebbak A, Lafri I, Kaced A, Bouhenna MM, Bachari K, Boumegoura A, Agred R, Boudchicha RH, Smadi MA, Maurin M, Bitam I. Identification of Algerian field-caught mosquito vectors by MALDI-TOF MS. Vet Parasitol Reg Stud Reports 2022; 31:100735. [PMID: 35569916 DOI: 10.1016/j.vprsr.2022.100735] [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: 03/15/2022] [Accepted: 04/20/2022] [Indexed: 06/15/2023]
Abstract
Vector-borne diseases represent a real threats worldwide, in reason of the lack of vaccine and cure for some diseases. Among arthropod vectors, mosquitoes are described to be the most dangerous animal on earth, resulting in an estimated 725,000 deaths per year due to their borne diseases. Geographical position of Algeria makes this country a high risk area for emerging and re-emerging diseases, such as dengue coming from north (Europe) and malaria from south (Africa). To prevent these threats, rapid and continuous surveillance of mosquito vectors is essential. For this purpose we aimed in this study to create a mosquito vectors locale database using MALDI-TOF mass spectrometry technology for rapid identification of these arthropods. This methodology was validated by testing 211 mosquitoes, including four species (Aedes albopictus, Culex pipiens, Culex quinquefasciatus, and Culiseta longiareolata), in two northern wilayahs of Algeria (Algiers and Bejaia). Species determination by MALDI TOF MS was highly concordant with reference phenotypic and genetic methods. Using this MALDI-TOF MS tool will allow better surveillance of mosquito species able to transmit mosquito borne diseases in Algeria.
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Affiliation(s)
- Zakaria Abdellahoum
- Laboratoire Biodiversité et Environnement: Interaction Génome, Faculté des Sciences Biologique, Université des Sciences et de la Technologie Houari Boumediene, Alger 16111, Algeria
| | - Amira Nebbak
- Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (CRAPC), Zone Industrielle, BP 284 Bou-Ismail, Tipaza, Algeria
| | - Ismail Lafri
- Laboratoire des Biotechnologies Liées à la Reproduction Animale, Institut des Sciences Vétérinaires, Université Blida 1, BP 270 Blida, Algeria.
| | - Amel Kaced
- Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (CRAPC), Zone Industrielle, BP 284 Bou-Ismail, Tipaza, Algeria
| | - Mustapha Mounir Bouhenna
- Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (CRAPC), Zone Industrielle, BP 284 Bou-Ismail, Tipaza, Algeria
| | - Khaldoun Bachari
- Centre de Recherche Scientifique et Technique en Analyses Physico-Chimiques (CRAPC), Zone Industrielle, BP 284 Bou-Ismail, Tipaza, Algeria
| | - Ali Boumegoura
- National Centre for Biotechnology Research, Ali Mendjli Nouvelle Ville, UV 03, BP E73 Constantine, Algeria.
| | - Rym Agred
- National Centre for Biotechnology Research, Ali Mendjli Nouvelle Ville, UV 03, BP E73 Constantine, Algeria.
| | - Rima Hind Boudchicha
- National Centre for Biotechnology Research, Ali Mendjli Nouvelle Ville, UV 03, BP E73 Constantine, Algeria.
| | - Mustapha Adnane Smadi
- National Centre for Biotechnology Research, Ali Mendjli Nouvelle Ville, UV 03, BP E73 Constantine, Algeria; Veterinary and Agricultural Sciences Institute, Department of Veterinary Sciences, University of Batna 1, Batna, Algeria
| | - Max Maurin
- Centre National de Référence des Francisella, Institut de Biologie et de Pathologie, Centre Hospitalier Universitaire Grenoble Alpes, 38043 Grenoble, France; Centre National de la Recherche Scientifique, TIMC-IMAG, UMR5525, Université Grenoble Alpes, 38400, Saint Martin d'Heres, France.
| | - Idir Bitam
- Laboratoire Biodiversité et Environnement: Interaction Génome, Faculté des Sciences Biologique, Université des Sciences et de la Technologie Houari Boumediene, Alger 16111, Algeria; Ecole Supérieure des Sciences de l'Aliment et des Industries Alimentaires, Alger 16004, Algeria
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17
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Buckner EA, Williams KF, Ramirez S, Darrisaw C, Carrillo JM, Latham MD, Lesser CR. A Field Efficacy Evaluation of In2Care Mosquito Traps in Comparison with Routine Integrated Vector Management at Reducing Aedes aegypti. JOURNAL OF THE AMERICAN MOSQUITO CONTROL ASSOCIATION 2021; 37:242-249. [PMID: 34817613 DOI: 10.2987/21-7038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Aedes aegypti is the predominant vector of dengue, chikungunya, and Zika viruses. This mosquito is difficult to control with conventional methods due to its container-inhabiting behavior and resistance to insecticides. Autodissemination of pyriproxyfen (PPF), a potent larvicide, has shown promise as an additional tool to control Aedes species in small-scale field trials. However, few large-scale field evaluations have been conducted. We undertook a 6-month-long large-scale field study to compare the effectiveness and operational feasibility of using In2Care Mosquito Traps (In2Care Traps, commercially available Aedes traps with PPF and Beauveria bassiana) compared to an integrated vector management (IVM) strategy consisting of source reduction, larviciding, and adulticiding for controlling Ae. aegypti eggs, larvae, and adults. We found that while the difference between treatments was only statistically significant for eggs and larvae (P < 0.05 for eggs and larvae and P > 0.05 for adults), the use of In2Care Traps alone resulted in 60%, 57%, and 57% fewer eggs, larvae, and adults, respectively, collected from that site compared to the IVM site. However, In2Care Trap deployment and maintenance were more time consuming and labor intensive than the IVM strategy. Thus, using In2Care Traps alone as a control method for large areas (e.g., >20 ha) may be less practical for control programs with the capacity to conduct ground and aerial larviciding and adulticiding. Based on our study results, we conclude that In2Care Traps are effective at suppressing Ae. aegypti and have the most potential for use in areas without sophisticated control programs and within IVM programs to target hotspots with high population levels and/or risk of Aedes-borne pathogen transmission.
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Susceptibility and barriers to infection of Colorado mosquitoes with Rift Valley fever virus. PLoS Negl Trop Dis 2021; 15:e0009837. [PMID: 34695125 PMCID: PMC8568276 DOI: 10.1371/journal.pntd.0009837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 11/04/2021] [Accepted: 09/24/2021] [Indexed: 11/19/2022] Open
Abstract
Rift Valley fever virus (RVFV) causes morbidity and mortality in humans and domestic ungulates in sub-Saharan Africa, Egypt, and the Arabian Peninsula. Mosquito vectors transmit RVFV between vertebrates by bite, and also vertically to produce infectious progeny. Arrival of RVFV into the United States by infected mosquitoes or humans could result in significant impacts on food security, human health, and wildlife health. Elucidation of the vectors involved in the post-introduction RVFV ecology is paramount to rapid implementation of vector control. We performed vector competence experiments in which field-collected mosquitoes were orally exposed to an epidemic strain of RVFV via infectious blood meals. We targeted floodwater Aedes species known to feed on cattle, and/or deer species (Aedes melanimon Dyar, Aedes increpitus Dyar, Aedes vexans [Meigen]). Two permanent-water-breeding species were targeted as well: Culiseta inornata (Williston) of unknown competence considering United States populations, and Culex tarsalis Coquillett as a control species for which transmission efficiency is known. We tested the potential for midgut infection, midgut escape (dissemination), ovarian infection (vertical transmission), and transmission by bite (infectious saliva). Tissues were assayed by plaque assay and RT-qPCR, to quantify infectious virus and confirm virus identity. Tissue infection data were analyzed using a within-host model under a Bayesian framework to determine the probabilities of infection outcomes (midgut-limited infection, disseminated infection, etc.) while estimating barriers to infection between tissues. Permanent-water-breeding mosquitoes (Cx. tarsalis and Cs. inornata) exhibited more efficient horizontal transmission, as well as potential for vertical transmission, which is contrary to the current assumptions of RVFV ecology. Barrier estimates trended higher for Aedes spp., suggesting systemic factors in the differences between these species and Cx. tarsalis and Cs. inornata. These data indicate higher potential for vertical transmission than previously appreciated, and support the consensus of RVFV transmission including a broad range of potential vectors. Rift Valley fever virus (RVFV) causes morbidity and mortality in humans and domestic ungulates in sub-Saharan Africa, Egypt, and the Arabian Peninsula. Mosquito vectors transmit RVFV between vertebrates by bite, and also vertically to produce infectious progeny. To inform vector control priorities upon the introduction of RVFV to the United States, we tested the ability of three floodwater Aedes species known to feed on cattle and/or deer in Colorado (Aedes vexans [Meigen], Aedes melanimon Dyar, Aedes increpitus Dyar) to transmit RVFV (vector competence). We also tested Culiseta inornata (Williston), and Culex tarsalis Coquillett which exhibits high vector competence, and the potential for vertical transmission by testing ovaries. These data were modeled to estimate the potential for virus transmission, based on the infection probabilities of different organs that serve as transmission barriers inside the mosquitoes. The permanent-water-breeders Cs. inornata and Cx. tarsalis exhibited higher efficiency of horizontal transmission as well as potential vertical transmission. Aedes species were less efficient at vertical and horizontal transmission, with high barriers to infection of and dissemination from the midgut. Overall, these data support the transmission of RVFV by a broad range of potential vectors in the United States, posing a major challenge for vector control if this virus is introduced.
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Koka H, Lutomiah J, Langat S, Koskei E, Nyunja A, Mutisya J, Mulwa F, Owaka S, Ofula V, Konongoi S, Eyase F, Sang R. Evidence of circulation of Orthobunyaviruses in diverse mosquito species in Kwale County, Kenya. Virol J 2021; 18:204. [PMID: 34641884 PMCID: PMC8507213 DOI: 10.1186/s12985-021-01670-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/16/2021] [Indexed: 12/05/2022] Open
Abstract
Background Arbovirus surveillance and recurrence of outbreaks in Kenya continues to reveal the re-emergence of viruses of public health importance. This calls for sustained efforts in early detection and characterization of these agents to avert future potential outbreaks. Methods A larval survey was carried out in three different sites in Kwale County, Vanga, Jego and Lunga Lunga. All containers in every accessible household and compound were sampled for immature mosquitoes. In addition, adult mosquitoes were also sampled using CO2-baited CDC light traps and BG-Sentinel traps in the three sites and also in Tsuini. The mosquitoes were knocked down using trimethylamine and stored in a liquid nitrogen shipper for transportation to the laboratory where they were identified to species, pooled and homogenized ready for testing. Results A total of 366 houses and 1730 containers were inspected. The House Index (HI), Container Index (CI) and Breateau Index (BI) for Vanga Island were (3%: 0.66: 3.66) respectively. In Jego, a rural site, the HI, CI and BI were (2.4%: 0.48: 2.4) respectively. In Lunga Lunga, a site in an urban area, the HI, CI and BI were (22.03%: 3.97: 29.7) respectively. The indices suggest that this region is at risk of arbovirus transmission given they were above the WHO threshold (CI > 1, HI > 1% and BI > 5). The most productive containers were the concrete tanks (44.4%), plastic tank (22.2%), claypot (13.3%), plastic drums (8.9%), plastic basins (4%), jerricans (1.2%) and buckets (0.3%). Over 20,200 adult mosquitoes were collected using CDC light traps, and over 9,200 using BG- sentinel traps. These mosquitoes were screened for viruses by inoculating in Vero cells. Eleven Orthobunyavirus isolates were obtained from pools of Ae. pembaensis (4), Ae. tricholabis (1), Cx. quinquefasciatus (3), Culex spp. (1) and Cx. zombaensis (2). Five of the Orthobunyaviruses were sequenced and four of these were determined to be Bunyamwera viruses while one isolate was found to be Nyando virus. One isolate remained unidentified. Conclusions These results indicate circulation of Orthobunyaviruses known to cause diverse grades of febrile illness with rash in humans in this region and highlights the need for continued monitoring and surveillance to avert outbreaks.
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Affiliation(s)
- Hellen Koka
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya.
| | - Joel Lutomiah
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Solomon Langat
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Edith Koskei
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Albert Nyunja
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - James Mutisya
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Francis Mulwa
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Samuel Owaka
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Victor Ofula
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Samson Konongoi
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
| | - Fredrick Eyase
- US Army Medical Research Directorate - Kenya, P. O. Box 606-00621, Nairobi, Kenya
| | - Rosemary Sang
- Centre for Virus Research, Kenya Medical Research Institute, P. O. Box 54628-00200, Nairobi, Kenya
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Jansen van Vuren P, Parry R, Khromykh AA, Paweska JT. A 1958 Isolate of Kedougou Virus (KEDV) from Ndumu, South Africa, Expands the Geographic and Temporal Range of KEDV in Africa. Viruses 2021; 13:v13071368. [PMID: 34372574 PMCID: PMC8309962 DOI: 10.3390/v13071368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022] Open
Abstract
The mosquito-borne flavivirus, Kedougou virus (KEDV), first isolated in Senegal in 1972, is genetically related to dengue, Zika (ZIKV) and Spondweni viruses (SPOV). Serological surveillance studies in Senegal and isolation of KEDV in the Central African Republic indicate occurrence of KEDV infections in humans, but to date, no disease has been reported. Here, we assembled the coding-complete genome of a 1958 isolate of KEDV from a pool of Aedes circumluteolus mosquitoes collected in Ndumu, KwaZulu-Natal, South Africa. The AR1071 Ndumu KEDV isolate bears 80.51% pairwise nucleotide identity and 93.34% amino acid identity with the prototype DakAar-D1470 strain and was co-isolated with SPOV through intracerebral inoculation of suckling mice and passage on VeroE6 cells. This historical isolate expands the known geographic and temporal range of this relatively unknown flavivirus, aiding future temporal phylogenetic calibration and diagnostic assay refinement.
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Affiliation(s)
- Petrus Jansen van Vuren
- Australian Centre for Disease Preparedness, CSIRO Health & Biosecurity, Private Bag 24, Geelong, VIC 3220, Australia
- Correspondence: ; Tel.: +613-5227-5700
| | - Rhys Parry
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; (R.P.); (A.A.K.)
| | - Alexander A. Khromykh
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD 4072, Australia; (R.P.); (A.A.K.)
- Australian Infectious Diseases Research Centre, Global Virus Network Centre of Excellence, Brisbane, QLD 4029, Australia
| | - Janusz T. Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg 2131, South Africa;
- Centre for Viral Zoonoses, Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa
- Faculty of Health Sciences, School of Pathology, University of Witwatersrand, Johannesburg 2050, South Africa
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Chiuya T, Masiga DK, Falzon LC, Bastos ADS, Fèvre EM, Villinger J. A survey of mosquito-borne and insect-specific viruses in hospitals and livestock markets in western Kenya. PLoS One 2021; 16:e0252369. [PMID: 34048473 PMCID: PMC8162702 DOI: 10.1371/journal.pone.0252369] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/15/2021] [Indexed: 11/18/2022] Open
Abstract
Aedes aegypti and Culex pipiens complex mosquitoes are prolific vectors of arboviruses that are a global threat to human and animal health. Increased globalization and ease of travel have facilitated the worldwide dissemination of these mosquitoes and the viruses they transmit. To assess disease risk, we determined the frequency of arboviruses in western Kenyan counties bordering an area of high arboviral activity. In addition to pathogenic viruses, insect-specific flaviviruses (ISFs), some of which are thought to impair the transmission of specific pathogenic arboviruses, were also evaluated. We trapped mosquitoes in the short and long rainy seasons in 2018 and 2019 at livestock markets and hospitals. Mosquitoes were screened for dengue, chikungunya and other human pathogenic arboviruses, ISFs, and their blood-meal sources as determined by high-resolution melting analysis of (RT-)PCR products. Of 6,848 mosquitoes collected, 89% were trapped during the long rainy season, with A. aegypti (59%) and Cx. pipiens sensu lato (40%) being the most abundant. Most blood-fed mosquitoes were Cx. pipiens s.l. with blood-meals from humans, chicken, and sparrow (Passer sp.). We did not detect dengue or chikungunya viruses. However, one Culex poicilipes female was positive for Sindbis virus, 30 pools of Ae. aegypti had cell fusing agent virus (CFAV; infection rate (IR) = 1.27%, 95% CI = 0.87%-1.78%); 11 pools of Ae. aegypti had Aedes flavivirus (AeFV; IR = 0.43%, 95% CI = 0.23%-0.74%); and seven pools of Cx. pipiens s.l. (IR = 0.23%, 95% CI = 0.1%-0.45%) and one pool of Culex annulioris had Culex flavivirus. Sindbis virus, which causes febrile illness in humans, can complicate the diagnosis and prognosis of patients with fever. The presence of Sindbis virus in a single mosquito from a population of mosquitoes with ISFs calls for further investigation into the role ISFs may play in blocking transmission of other arboviruses in this region.
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Affiliation(s)
- Tatenda Chiuya
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- * E-mail: , (TC); (JV)
| | - Daniel K. Masiga
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Laura C. Falzon
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, United Kingdom
- International Livestock Research Institute, Nairobi, Kenya
| | - Armanda D. S. Bastos
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Eric M. Fèvre
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Neston, United Kingdom
- International Livestock Research Institute, Nairobi, Kenya
| | - Jandouwe Villinger
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- * E-mail: , (TC); (JV)
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Rift Valley fever virus detection in susceptible hosts with special emphasis in insects. Sci Rep 2021; 11:9822. [PMID: 33972596 PMCID: PMC8110843 DOI: 10.1038/s41598-021-89226-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 04/15/2021] [Indexed: 11/09/2022] Open
Abstract
Rift Valley fever phlebovirus (RVFV, Phenuiviridae) is an emerging arbovirus that can cause potentially fatal disease in many host species including ruminants and humans. Thus, tools to detect this pathogen within tissue samples from routine diagnostic investigations or for research purposes are of major interest. This study compares the immunohistological usefulness of several mono- and polyclonal antibodies against RVFV epitopes in tissue samples derived from natural hosts of epidemiologic importance (sheep), potentially virus transmitting insect species (Culex quinquefasciatus, Aedes aegypti) as well as scientific infection models (mouse, Drosophila melanogaster, C6/36 cell pellet). While the nucleoprotein was the epitope most prominently detected in mammal and mosquito tissue samples, fruit fly tissues showed expression of glycoproteins only. Antibodies against non-structural proteins exhibited single cell reactions in salivary glands of mosquitoes and the C6/36 cell pellet. However, as single antibodies exhibited a cross reactivity of varying degree in non-infected specimens, a careful interpretation of positive reactions and consideration of adequate controls remains of critical importance. The results suggest that primary antibodies directed against viral nucleoproteins and glycoproteins can facilitate RVFV detection in mammals and insects, respectively, and therefore will allow RVFV detection for diagnostic and research purposes.
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Wichgers Schreur PJ, Vloet RPM, Kant J, van Keulen L, Gonzales JL, Visser TM, Koenraadt CJM, Vogels CBF, Kortekaas J. Reproducing the Rift Valley fever virus mosquito-lamb-mosquito transmission cycle. Sci Rep 2021; 11:1477. [PMID: 33446733 PMCID: PMC7809480 DOI: 10.1038/s41598-020-79267-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 11/30/2020] [Indexed: 01/25/2023] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne bunyavirus that is pathogenic to ruminants and humans. The virus is endemic to Africa and the Arabian Peninsula where outbreaks are characterized by abortion storms and mortality of newborns, particularly in sheep herds. Vector competence experiments in laboratory settings have suggested that over 50 mosquito species are capable of transmitting RVFV. Transmission of mosquito-borne viruses in the field is however influenced by numerous factors, including population densities, blood feeding behavior, extrinsic incubation period, longevity of vectors, and viremia levels in vertebrate hosts. Animal models to study these important aspects of RVFV transmission are currently lacking. In the present work, RVFV was transmitted to European (Texel-swifter cross-breed) lambs by laboratory-reared Aedes aegypti mosquitoes that were infected either by membrane feeding on a virus-spiked blood meal or by feeding on lambs that developed viremia after intravenous inoculation of RVFV. Feeding of mosquitoes on viremic lambs resulted in strikingly higher infection rates as compared to membrane feeding. Subsequent transmission of RVFV from lamb to lamb by infected mosquitoes was highly efficient in both models. The animal models described here can be used to study mosquito-mediated transmission of RVFV among the major natural target species and to evaluate the efficacy of vaccines against mosquito-mediated RVFV infection.
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Affiliation(s)
| | | | - Jet Kant
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | | | - Jose L Gonzales
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Tessa M Visser
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | | | - Chantal B F Vogels
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Jeroen Kortekaas
- Wageningen Bioveterinary Research, Lelystad, The Netherlands. .,Laboratory of Virology, Wageningen University & Research, Wageningen, The Netherlands.
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Tchouassi DP, Torto B, Sang R, Riginos C, Ezenwa VO. Large herbivore loss has complex effects on mosquito ecology and vector-borne disease risk. Transbound Emerg Dis 2020; 68:2503-2513. [PMID: 33170555 DOI: 10.1111/tbed.13918] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/25/2020] [Accepted: 11/06/2020] [Indexed: 12/15/2022]
Abstract
Loss of biodiversity can affect transmission of infectious diseases in at least two ways: by altering host and vector abundance or by influencing host and vector behaviour. We used a large herbivore exclusion experiment to investigate the effects of wildlife loss on the abundance and feeding behaviour of mosquito vectors and to explore consequences for vector-borne disease transmission. Large herbivore loss affected both mosquito abundance and blood-feeding behaviour. For Aedes mcintoshi, the dominant mosquito species in our study and a primary vector of Rift Valley fever virus (RVFV), abundance decreased with large herbivore loss, while blood feeding on humans increased. Despite an elevated human biting rate in the absence of large herbivores, we estimated that the potential for RVFV transmission to humans doubles in the presence of large herbivores. These results demonstrate that multiple effects of biodiversity loss on vectors can lead to counterintuitive outcomes for human disease risk.
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Affiliation(s)
- David P Tchouassi
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | - Vanessa O Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
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Rodrigue Simonet PN, Alexandre Michel NN, Abel W, Albert E, Martin Hermann G, Franziska S. Diversity and Abundance of Potential Vectors of Rift Valley Fever Virus in the North Region of Cameroon. INSECTS 2020; 11:insects11110814. [PMID: 33227891 PMCID: PMC7699143 DOI: 10.3390/insects11110814] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/01/2020] [Accepted: 11/02/2020] [Indexed: 11/16/2022]
Abstract
Simple Summary Rift Valley fever (RVF) is a mosquito-borne disease caused by the Rift Valley fever virus (RVFV) transmitted by various genera of mosquitoes usually classified into primary vectors and secondary vectors. The former, belonging to the genus Aedes, are known for their ability to lay drought resistant eggs that can maintain the virus on dry soil for many years in geomorphic structures in the form of shallow depressions. After heavy rains, mosquitoes hatch from these eggs, some of which are infected and transmit the virus to neighboring animals. The secondary vectors, mainly mosquitoes of the genera Culex, Anopheles, and Mansonia, can colonize these sites, reproduce in abundance, and subsequently spread RVFV. Although the northern regions of Cameroon host more than half of the country’s cattle, sheep, and goat populations, there is a dearth of information on the occurrence and transmission of RVFV and its vectors. The very common transhumance of animals during periods of drought leads to contact between domestic and wild animals and creates opportunities for cross-transmission of the virus. It also increases the possibilities of exposure of herds to vectors, in particular at water points. In addition, rare heavy rainfall, flooding, and irrigation-based agricultural practices in these regions provide conditions for vector proliferation and increase the risk of the spread of vector-borne diseases, including RVF. Therefore, this study aimed to determine species diversity and spatial distribution of potential RVFV vectors in the North Region of Cameroon. The study revealed the presence of potential primary and secondary vectors of RVFV with an abundance and a diversity varying according to the ecological sites studied. This presence of potential vectors with their variable number per trap, per night, or per site may create areas of variable risk for disease transmission to susceptible hosts. Molecular analysis (PCR) tests for RVFV RNA research and viral isolation methods on these vectors to determine their role in the epidemiology and control of RVF cannot be overemphasized. Abstract Rift Valley fever (RVF) is a major viral zoonosis transmitted by mosquitoes. The virus is endemic in most parts of sub-Saharan Africa and can affect humans, livestock, and wild ungulates. Knowledge of the biology of vectors of Rift Valley fever virus (RVFV) is essential for the establishment of effective control measures of the disease. The objective of this study was to determine the species diversity and relative abundance of potential RVFV vectors in the North Region of Cameroon. Adult mosquitoes were trapped during the wet and dry seasons from December 2017 to January 2019 with “EVS Light” traps with CO2 baits placed at selected sites. The captured mosquitoes were identified using dichotomous keys according to standard procedures. The abundance was calculated with regard to site, zone, and collection season. A total of 27,851 mosquitoes belonging to four genera (Aedes, Anopheles, Mansonia, and Culex) and comprising 31 species were caught (including 22 secondary vectors (98.05%) and nine primary vectors (1.94%). The total number of mosquitoes varied significantly depending on the locality (p-value < 0.001). The average number of mosquitoes collected per trap night was significantly higher in irrigated areas (p-value < 0.001), compared to urban and non-irrigated areas. The study revealed the presence of potential primary and secondary vectors of RVFV with varying abundance and diversity according to locality and ecological site in the North Region of Cameroon. The results showed that the genus Mansonia with the species Ma. uniformis and Ma. africana formed the dominant taxon (52.33%), followed by the genera Culex (45.04%) and Anopheles (2.61%). The need for molecular analysis (PCR) tests for RVFV RNA research and viral isolation methods on these vectors to determine their role in the epidemiology and control of RVF cannot be overemphasized.
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Affiliation(s)
- Poueme Namegni Rodrigue Simonet
- National Veterinary Laboratory Cameroon (LANAVET), Garoua BP 503, Cameroon;
- Department of Biological Sciences, The University of Ngaoundere, Ngaoundere BP 454, Cameroon;
- Correspondence:
| | | | - Wade Abel
- National Veterinary Laboratory Cameroon (LANAVET), Garoua BP 503, Cameroon;
| | - Eisenbarth Albert
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, 17493 Greifswald, Insel Riems, Germany; (E.A.); (G.M.H.); (S.F.)
| | - Groschup Martin Hermann
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, 17493 Greifswald, Insel Riems, Germany; (E.A.); (G.M.H.); (S.F.)
| | - Stoek Franziska
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, 17493 Greifswald, Insel Riems, Germany; (E.A.); (G.M.H.); (S.F.)
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Asebe G, Mamo G, Michlmayr D, Abegaz WE, Endale A, Medhin G, Larrick JW, Legesse M. Seroprevalence of Rift Valley Fever and West Nile Fever in Cattle in Gambella Region, South West Ethiopia. VETERINARY MEDICINE (AUCKLAND, N.Z.) 2020; 11:119-130. [PMID: 33244452 PMCID: PMC7683499 DOI: 10.2147/vmrr.s278867] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/27/2020] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Rift Valley fever (RVF) and West Nile fever (WNF) are re-emerging mosquito-borne zoonotic diseases that cause public health and economic crises. Ethiopia shares borders with South Sudan and Kenya, where these diseases are often documented. The free movement of animals and humans across these borders expects to increase the spread of these diseases. The current study was conducted to assess the occurrence of these diseases in the Gambella region of Ethiopia. METHODOLOGY We collected a total of 368 cattle serum samples from the Lare district on the border of South Sudan and measured the presence of IgG antibody against RVF and WNF virus infections using enzyme-linked immunosorbent assays (ELISA). RESULTS The prevalence of anti-RVF virus IgG antibody was 7.6% (95% CI: 5.3-10.82%), while that of anti-WNF virus IgG antibody was 5.4% (95% CI: 3.52-8.29%). In this study higher seroprevalence of IgG antibodies to RVF virus infection was observed comparing to the WNF virus in cattle. There was no significant association between the prevalence and the cattle age, sex or sampled locations. CONCLUSION The detection of IgG antibody to RVF and WNF virus infections in the Gambella region warrants further study of active case findings and the dynamics of transmission.
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Affiliation(s)
- Getahun Asebe
- Department of Veterinary Microbiology, Immunology and Public Health, College of Veterinary Medicine, Addis Ababa University, Bishoftu, Ethiopia
- College of Agriculture and Natural Resources, Gambella University, Gambella, Ethiopia
| | - Gezahegne Mamo
- Department of Veterinary Microbiology, Immunology and Public Health, College of Veterinary Medicine, Addis Ababa University, Bishoftu, Ethiopia
| | - Daniela Michlmayr
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California Berkeley, Berkeley, CA, USA
| | - Woldaregay Erku Abegaz
- Department of Microbiology, Immunology & Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Adugna Endale
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- School of Medicine, College of Medicine and Health Sciences, Dire Dawa University, Dire Dawa, Ethiopia
| | - Girmay Medhin
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | - Mengistu Legesse
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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Munyao V, Karisa J, Munyao CM, Ngari M, Menza N, Peshu N, Rono M, Mbogo C, Mwangangi J. Surveillance of Culicine Mosquitoes in Six Villages of Taita-Taveta County, Kenya, With Host Determinations From Blood-Fed Females. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1972-1982. [PMID: 32533693 PMCID: PMC7613318 DOI: 10.1093/jme/tjaa109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Indexed: 06/11/2023]
Abstract
Culicine mosquitoes are vectors of human disease-causing pathogens like filarial worms and several arthropod-borne viruses (arboviruses). Currently, there has been an increase in emerging and re-emerging vector-borne diseases along coastal Kenya, which has been of major concern in public health. This study aimed at determining culicine mosquito species abundance, diversity and their host feeding preferences in Taita-Taveta County, Coastal Kenya. Entomological sampling was done during the long-wet season (March and May) and long dry season (June to October) 2016-2018. Mosquito sampling was done using CDC light traps and Backpack aspiration for indoor and outdoor environments. All culicine mosquitoes collected were identified morphologically and categorized according to their physiological status. Blood fed culicine mosquitoes were tested for bloodmeal sources using ELISA. In total, 3,278 culicine mosquitoes were collected, of which 738 (22.5 %) were found indoors and 2,540, (77.5 %) outdoors. The mosquitoes consisted of 18 species belonging to four genera: Aedes (7), Culex (8), Mansonia (2), and Coquillettidia (1). Overall, there was high mosquito species diversity (H) in outdoors (H = 2.4339) than in indoors (H = 2.2523), whereas even distribution (EH) was higher in indoors (EH = 0.9064) than outdoors (EH = 0.8266). Majorly the bloodmeals identified were from multiple host sources with (51.6%), single hosts (41.3%), and unidentified (7.2%). This study has demonstrated a high diversity of culicine mosquitoes with relaxed feeding tendencies. These mosquitoes are contributing to mosquito biting nuisance and the likelihood of exposure of populations to diseases of public health.
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Affiliation(s)
- Vanessa Munyao
- Department of Medical Laboratory Sciences, Kenyatta University, Nairobi, Kenya
- Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Coast, Kilifi, Kenya
| | - Jonathan Karisa
- Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Coast, Kilifi, Kenya
- Pwani University Bioscience Research Centre (PUBreC), Kilifi, Kenya
| | | | - Moses Ngari
- Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Coast, Kilifi, Kenya
| | - Nelson Menza
- Department of Medical Laboratory Sciences, Kenyatta University, Nairobi, Kenya
| | - Norbert Peshu
- Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Coast, Kilifi, Kenya
| | - Martin Rono
- Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Coast, Kilifi, Kenya
- Pwani University Bioscience Research Centre (PUBreC), Kilifi, Kenya
| | - Charles Mbogo
- Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Coast, Kilifi, Kenya
| | - Joseph Mwangangi
- Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Coast, Kilifi, Kenya
- Pwani University Bioscience Research Centre (PUBreC), Kilifi, Kenya
- KEMRI, Center for Vector Disease Control, Kwale, Kenya
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Mastrodomenico V, Esin JJ, Qazi S, Khomutov MA, Ivanov AV, Mukhopadhyay S, Mounce BC. Virion-Associated Polyamines Transmit with Bunyaviruses to Maintain Infectivity and Promote Entry. ACS Infect Dis 2020; 6:2490-2501. [PMID: 32687697 DOI: 10.1021/acsinfecdis.0c00402] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Viruses require host cell metabolites to productively infect, and the mechanisms by which viruses usurp these molecules are diverse. One group of cellular metabolites important in virus infection is the polyamines, small positively charged molecules involved in cell cycle, translation, and nucleic acid metabolism, among other cellular functions. Polyamines support replication of diverse viruses, and they are important for processes such as transcription, translation, and viral protein enzymatic activity. Rift Valley fever virus (RVFV) is a negative and ambisense RNA virus that requires polyamines to produce infectious particles. In polyamine depleted conditions, noninfectious particles are produced that interfere with virus replication and stimulate immune signaling. Here, we find that RVFV relies on virion-associated polyamines to maintain infectivity and enhance viral entry. We show that RVFV replication is facilitated by a limited set of polyamines and that spermidine and closely related molecules associate with purified virions and transmit from cell to cell during infection. Virion-associated spermidine maintains virion infectivity, as virions devoid of polyamines rapidly lose infectivity and are temperature sensitive. Further, virions without polyamines bind to cells but exhibit a defect in entry, requiring more acidic conditions than virions containing spermidine. These data highlight a unique role for polyamines, and spermidine particularly, to maintain virus infectivity. Further, these studies are the first to identify polyamines associated with RVFV virions. Targeting polyamines represents a promising antiviral strategy, and this work highlights a new mechanism by which we can inhibit virus replication through FDA-approved polyamine depleting pharmaceuticals.
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Affiliation(s)
- Vincent Mastrodomenico
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
| | - Jeremy J. Esin
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
- Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
| | - Shefah Qazi
- Department of Biology, Indiana University, Bloomington, Indiana 47405, United States
| | - Maxim A. Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Alexander V. Ivanov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | | | - Bryan C. Mounce
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
- Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
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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.
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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
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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.
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Tigoi C, Sang R, Chepkorir E, Orindi B, Arum SO, Mulwa F, Mosomtai G, Limbaso S, Hassan OA, Irura Z, Ahlm C, Evander M. High risk for human exposure to Rift Valley fever virus in communities living along livestock movement routes: A cross-sectional survey in Kenya. PLoS Negl Trop Dis 2020; 14:e0007979. [PMID: 32084127 PMCID: PMC7055907 DOI: 10.1371/journal.pntd.0007979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 03/04/2020] [Accepted: 12/09/2019] [Indexed: 11/18/2022] Open
Abstract
Introduction Multiple outbreaks of Rift Valley Fever (RVF) with devastating effects have occurred in East Africa. These outbreaks cause disease in both livestock and humans and affect poor households most severely. Communities living in areas practicing nomadic livestock movement may be at higher risk of infection. This study sought to i) determine the human exposure to Rift Valley fever virus (RVFV) in populations living within nomadic animal movement routes in Kenya; and ii) identify risk factors for RVFV infection in these communities. Methods A cross-sectional descriptive study design was used. Samples were collected from the year 2014 to 2015 in a community-based sampling exercise involving healthy individuals aged ≥18 years from Isiolo, Tana River, and Garissa counties. In total, 1210 samples were screened by ELISA for the presence of immunoglobulin IgM and IgG antibodies against RVFV. Positive results were confirmed by plaque reduction neutralization test. Results Overall, IgM and IgG prevalence for all sites combined was 1.4% (95% CI 0.8–2.3%) and 36.4% (95% CI 33.8–39.2%), respectively. Isiolo County recorded a non-significant higher IgG prevalence of 38.8% than Garissa 35.9% and Tana River 32.2% (Chi square = 2.5, df = 2, p = 0.287). Males were significantly at higher risk of infection by RVFV than females (OR = 1.67, 95% CI 1.17–2.39, p<0.005). Age was significantly associated with RVFV infection (Wald Chi = 94.2, df = 5, p<0.0001). Individuals who had regular contact with cattle (OR = 1.38, 95%CI 1.01–1.89) and donkeys (OR = 1.38, 95%CI 1.14–1.67), or contact with animals through birthing (OR = 1.69, 95%CI 1.14–2.51) were significantly at a greater risk of RVFV infection than those who did not. Conclusion This study demonstrated that although the Isiolo County has been classified as being at medium risk for RVF, virus infection appeared to be as prevalent in humans as in Tana River and Garissa, which have been classified as being at high risk. Populations in these counties live within nomadic livestock movement routes and therefore at risk of being exposed to the RVFV. Interventions to control RVFV infections therefore, should target communities living along livestock movement pathways. Rift Valley fever (RVF) is a neglected mosquito-borne zoonotic disease that causes major outbreaks and economic harm to human and ruminants health leading to increased poverty within affected communities. RVF is caused by RVF virus (RVFV) affecting humans and a wide range of ruminants. The virus is transmitted through bites from mosquitoes and exposure to blood, body fluids, or tissues of infected ruminants. It was first isolated in Kenya in 1930 and several outbreaks have been recorded in many countries in sub-Saharan Africa. We studied pastoralist communities living along livestock migratory routes. Migratory livestock do move long distances in search of water and pasture and may be at higher risk of exposure to RVFV. We also determined risk factors for RVFV infection by studying age, gender, contact with animals through birthing, and occupation. Prevention and control of RVFV infection can target significant risk factors to prevent spread and re-occurrence of outbreaks.
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Affiliation(s)
- Caroline Tigoi
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- * E-mail:
| | - Rosemary Sang
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Center for Virus Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Edith Chepkorir
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Benedict Orindi
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | - Francis Mulwa
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Gladys Mosomtai
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Samson Limbaso
- Center for Virus Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Osama A. Hassan
- Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden
| | - Zephania Irura
- Ministry of Public Health and Sanitation, Nairobi, Kenya
| | - Clas Ahlm
- Department of Clinical Microbiology, Infection and Immunology, Umeå University, Umeå, Sweden
| | - Magnus Evander
- Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden
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Turell MJ, Cohnstaedt LW, Wilson WC. Effect of Environmental Temperature on the Ability of Culex tarsalis and Aedes taeniorhynchus (Diptera: Culicidae) to Transmit Rift Valley Fever Virus. Vector Borne Zoonotic Dis 2020; 20:454-460. [PMID: 32017863 DOI: 10.1089/vbz.2019.2554] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rift Valley fever virus (RVFV) causes severe disease in domestic ungulates (cattle, goats, and sheep) and a febrile illness in humans (with ∼1% case fatality rate). This virus has been spreading geographically, and there is concern of it spreading to Europe or the Americas. Environmental temperature can significantly affect the ability of mosquitoes to transmit an arbovirus. However, these effects are not consistent among viruses or mosquito species. Therefore, we evaluated the effect of incubation temperatures ranging from 14°C to 30°C on infection and dissemination rates for Culex tarsalis and Aedes taeniorhynchus allowed to feed on hamsters infected with RVFV. Engorged mosquitoes were randomly allocated to cages and placed in incubators maintained at 14°C, 18°C, 22°C, 26°C, or 30°C. Although infection rates detected in Cx. tarsalis increased with increasing holding temperature, holding temperature had no effect on infection rates detected in Ae. taeniorhynchus. However, for both species, the percentage of mosquitoes with a disseminated infection after specific extrinsic incubation periods (4, 7, 10, 14, 17, or 21 days) increased with increasing incubation holding temperature, even after adjusting for the apparent increase in infection rate in Cx. tarsalis. The effects of environmental factors, such as ambient temperature, need to be taken into account when developing models for viral persistence and spread in nature.
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Affiliation(s)
- Michael J Turell
- Virology Division, Department of Vector Assessment, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, Maryland
| | - Lee W Cohnstaedt
- Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Manhattan, Kansas
| | - William C Wilson
- Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Manhattan, Kansas
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Mbotha D, Hoppenheit A, Lindahl J, Bett B, Grace D, Lutomiah J, Pieper L, Kairu-Wanyoike S, Clausen PH. Relative Distribution, Diversity, and Bloodmeal Sources of Mosquitoes and Known Vectors of Rift Valley Fever Phlebovirus in Three Differing Ecosystems in Bura, Tana River County, Kenya. Vector Borne Zoonotic Dis 2020; 20:365-373. [PMID: 31990632 DOI: 10.1089/vbz.2019.2503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Environmental modifications disturb the equilibrium of mosquito populations, altering the risk of mosquito-borne diseases. Mosquito distribution, diversity, and bloodmeal sources were examined to compare Rift Valley fever (RVF) risk among irrigated, riverine, and pastoral ecosystems in Bura, Tana River County, Kenya, between September 2014 and June 2015. Thirty-eight households and 21 irrigation fields were selected for the study. Mosquitoes were trapped with carbon dioxide-impregnated CDC traps, one trap per household and three traps per irrigated field, and morphologically identified using taxonomic keys. Host DNA was extracted from engorged females and cytochrome b genes amplified by PCR to identify sources of bloodmeals. A total of 21,015 mosquitoes were collected; 5742 within households in the 3 ecosystems and 15,273 within irrigated fields. Mosquitoes collected within irrigated fields belonged to 8 genera and 37 species, while those from households within the irrigation scheme belonged to 6 genera and 29 species. Collections from riverine and pastoral households belonged to five and four genera, respectively. The most abundant genera in the irrigated fields were Aedes (21%) and Mansonia (22%), while Anopheles (43%) was the most abundant within households. Most mosquitoes in riverine and pastoral households belonged to Anopheles (76%) and Aedes (65%) genera, respectively. Seasonal variation driven by rainfall was evidenced by spikes in mosquito numbers within irrigated and riverine ecosystems. Host species identification revealed that goats and humans were the main sources of bloodmeal. There was an overall increase in mosquito abundance and diversity as a result of the presence of the irrigated ecosystem in this county, and an increased availability of highly RVF-susceptible hosts as a result of the establishment and concentration of residential areas, promoting potential vector-host contacts. These results highlight the impact of anthropogenic changes on mosquito ecology, potentially heightening the risk of transmission and maintenance of RVF in this region.
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Affiliation(s)
- Deborah Mbotha
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universitaet Berlin, Berlin, Germany.,International Livestock Research Institute, Nairobi, Kenya
| | - Antje Hoppenheit
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universitaet Berlin, Berlin, Germany
| | - Johanna Lindahl
- International Livestock Research Institute, Nairobi, Kenya.,Food Safety and Zoonoses, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Bernard Bett
- International Livestock Research Institute, Nairobi, Kenya
| | - Delia Grace
- International Livestock Research Institute, Nairobi, Kenya
| | - Joel Lutomiah
- Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Laura Pieper
- Institute for Veterinary Epidemiology and Biostatistics, Freie Universitaet Berlin, Berlin, Germany
| | | | - Peter-Henning Clausen
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universitaet Berlin, Berlin, Germany
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Tchouassi DP, Marklewitz M, Chepkorir E, Zirkel F, Agha SB, Tigoi CC, Koskei E, Drosten C, Borgemeister C, Torto B, Junglen S, Sang R. Sand Fly-Associated Phlebovirus with Evidence of Neutralizing Antibodies in Humans, Kenya. Emerg Infect Dis 2019; 25:681-690. [PMID: 30882303 PMCID: PMC6433041 DOI: 10.3201/eid2504.180750] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We describe a novel virus, designated Ntepes virus (NPV), isolated from sand flies in Kenya. NPV has the characteristic phlebovirus trisegmented genome architecture and is related to, but distinct from, Gabek Forest phlebovirus. Diverse cell cultures derived from wildlife, livestock, and humans were susceptible to NPV, with pronounced permissiveness in swine and rodent cells. NPV infection of newborn mice caused rapid and fatal illness. Permissiveness for NPV replication in sand fly cells, but not mosquito cells, suggests a vector-specific adaptation. Specific neutralizing antibodies were found in 13.9% (26/187) of human serum samples taken at the site of isolation of NPV as well as a disparate site in northeastern Kenya, suggesting a wide distribution. We identify a novel human-infecting arbovirus and highlight the importance of rural areas in tropical Africa for arbovirus surveillance as well as extending arbovirus surveillance to include hematophagous arthropods other than mosquitoes.
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Campbell LP, Reuman DC, Lutomiah J, Peterson AT, Linthicum KJ, Britch SC, Anyamba A, Sang R. Predicting Abundances of Aedes mcintoshi, a primary Rift Valley fever virus mosquito vector. PLoS One 2019; 14:e0226617. [PMID: 31846495 PMCID: PMC6917266 DOI: 10.1371/journal.pone.0226617] [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: 06/24/2019] [Accepted: 12/02/2019] [Indexed: 11/18/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic arbovirus with important livestock and human health, and economic consequences across Africa and the Arabian Peninsula. Climate and vegetation monitoring guide RVFV forecasting models and early warning systems; however, these approaches make monthly predictions and a need exists to predict primary vector abundances at finer temporal scales. In Kenya, an important primary RVFV vector is the mosquito Aedes mcintoshi. We used a zero-inflated negative binomial regression and multimodel averaging approach with georeferenced Ae. mcintoshi mosquito counts and remotely sensed climate and topographic variables to predict where and when abundances would be high in Kenya and western Somalia. The data supported a positive effect on abundance of minimum wetness index values within 500 m of a sampling site, cumulative precipitation values 0 to 14 days prior to sampling, and elevated land surface temperature values ~3 weeks prior to sampling. The probability of structural zero counts of mosquitoes increased as percentage clay in the soil decreased. Weekly retrospective predictions for unsampled locations across the study area between 1 September and 25 January from 2002 to 2016 predicted high abundances prior to RVFV outbreaks in multiple foci during the 2006-2007 epizootic, except for two districts in Kenya. Additionally, model predictions supported the possibility of high Ae. mcintoshi abundances in Somalia, independent of Kenya. Model-predicted abundances were low during the 2015-2016 period when documented outbreaks did not occur, although several surveillance systems issued warnings. Model predictions prior to the 2018 RVFV outbreak indicated elevated abundances in Wajir County, Kenya, along the border with Somalia, but RVFV activity occurred west of the focus of predicted high Ae. mcintoshi abundances.
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Affiliation(s)
- Lindsay P. Campbell
- Florida Medical Entomology Laboratory, IFAS, University of Florida, Vero Beach, Florida, United States of America
- Department of Entomology and Nematology, IFAS, University of Florida, Gainesville, Florida, United States of America
| | - Daniel C. Reuman
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
- Kansas Biological Survey, University of Kansas, Lawrence, Kansas, United States of America
- Laboratory of Populations, Rockefeller University, New York, New York, United States of America
| | - Joel Lutomiah
- Kenya Medical Research Institute, Nairobi, Kenya
- United States Army Medical Research Directorate – Africa, Nairobi, Kenya
| | - A. Townsend Peterson
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, United States of America
- Biodiversity Institute, University of Kansas, Lawrence, Kansas, United States of America
| | - Kenneth J. Linthicum
- United States Department of Agriculture, Agricultural Research Service Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, Florida, United States of America
| | - Seth C. Britch
- United States Department of Agriculture, Agricultural Research Service Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, Florida, United States of America
| | - Assaf Anyamba
- Universities Space Research Association, Columbia, Maryland, United States of America
- NASA Goddard Space Flight Center, Biospheric Sciences Laboratory, Greenbelt, Maryland, United States of America
| | - Rosemary Sang
- Kenya Medical Research Institute, Nairobi, Kenya
- United States Army Medical Research Directorate – Africa, Nairobi, Kenya
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Bashir RSE, Hassan OA. A One Health perspective to identify environmental factors that affect Rift Valley fever transmission in Gezira state, Central Sudan. Trop Med Health 2019; 47:54. [PMID: 31798311 PMCID: PMC6880409 DOI: 10.1186/s41182-019-0178-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/26/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Rift Valley fever (RVF) is a zoonotic viral vector-borne disease that affects both animals and humans and leads to severe economic consequences. RVF outbreaks are triggered by a favorable environment and flooding, which enable mosquitoes to proliferate and spread the virus further. RVF is endemic to Africa and has spread to Saudi Arabia and Yemen. There is great concern that RVF may spread to previously unaffected geographic regions due to climate change. We aimed to better understand the spatiotemporal pattern of the 2007 RVF outbreak at the human-animal-environment interface and to determine environmental factors that may have effects on RVF occurrence in Gezira state, Sudan. MATERIALS AND METHODS We compiled epidemiological, environmental, and spatiotemporal data across time and space using remote sensing and a geographical information system (GIS). The epidemiological data included 430 RVF human cases as well as human and animal population demographic data for each locality. The cases were collected from 41 locations in Gezira state. The environmental data represent classified land cover during 2007, the year of the RVF outbreak, and the average of the Normalized Difference Vegetation Index (NDVI) for 6 months of 2007 is compared with those of 2010 and 2014, when there was no RVF outbreak. To determine the effect of the environmental factors such as NDVI, soil type, and RVF case's location on the Blue Nile riverbank on RVF incidence in Gezira state, a multilevel logistic regression model was carried out. RESULTS We found that the outbreak in Gezira state occurred as a result of interaction among animals, humans, and the environment. The multilevel logistic regression model (F = 43,858, df = 3, p = 0.000) explained 23% of the variance in RVF incidence due to the explanatory variables. Notably, soil type (β = 0.613, t = 11.284, p = 0.000) and NDVI (β = - 0.165, t = - 3.254, p = 0.001) were the explanatory environmental factors that had significant effects on RVF incidence in 2007 in Gezira state, Sudan. CONCLUSIONS Precise remote sensing and the GIS technique, which rely on environmental indices such as NDVI and soil type that are satellite-derived, can contribute to establishing an early warning system for RVF in Sudan.Future preparedness and strengthening the capacity of regional laboratories are necessary for early notification of outbreaks in animals and humans.
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Affiliation(s)
- Rania Salah Eldien Bashir
- Animal Health Directorate, General Directorate of Animal Health and Epizootic Diseases Control, Ministry of Livestock, Khartoum, Sudan
| | - Osama Ahmed Hassan
- The Centre for Global Health, Department of Community Medicine and Global Health, Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Clinical Microbiology, Unit of Virology, Faculty of Medicine, Umeå University, Umeå, Sweden
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Karuitha M, Bargul J, Lutomiah J, Muriu S, Nzovu J, Sang R, Mwangangi J, Mbogo C. Larval habitat diversity and mosquito species distribution along the coast of Kenya. Wellcome Open Res 2019; 4:175. [PMID: 32509966 PMCID: PMC7241275 DOI: 10.12688/wellcomeopenres.15550.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2019] [Indexed: 11/20/2022] Open
Abstract
Background: Management of arboviruses relies heavily on vector control. Implementation and sustenance of effective control measures requires regular surveillance of mosquito occurrences, species abundance and distribution. The current study evaluated larval habitat diversity and productivity, mosquito species diversity and distribution in selected sites along the coast of Kenya. Methods: A cross-sectional survey of mosquito breeding habitats, species diversity and distribution was conducted in urban, peri-urban and forested ecological zones in Mombasa and Kilifi counties. Results: A total of 13,009 immature mosquitoes were collected from 17 diverse aquatic habitats along the coast of Kenya. Larval productivity differed significantly (F (16, 243) = 3.21, P < 0.0001) among the aquatic habitats, with tyre habitats recording the highest larval population. Culex pipiens (50.17%) and Aedes aegypti (38.73%) were the dominant mosquito species in urban areas, while Ae. vittatus (89%) was the dominant species in forested areas. In total, 4,735 adult mosquitoes belonging to 19 species were collected in Haller Park, Bamburi, Gede and Arabuko Sokoke forest. Urban areas supported higher densities of Ae. aegypti compared to peri-urban and forest areas, which, on the other hand, supported greater mosquito species diversity. Conclusions: High Ae. aegypti production in urban and peri-urban areas present a greater risk of arbovirus outbreaks. Targeting productive habitats of Aedes aegypti, such as discarded tyres, containers and poorly maintained drainage systems in urban areas and preventing human-vector contact in peri-urban and forested areas could have a significant impact on the prevalence of arboviruses along the coast of Kenya, forestalling the periodic outbreaks experienced in the region.
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Affiliation(s)
- Miriam Karuitha
- Vector Biology Unit, Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Research Coast, Kilifi, P.O. Box 230-80100, Kenya
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
| | - Joel Bargul
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
- The Animal Health Department, International Centre of Insect Physiology and Ecology, Nairobi, P.O. Box 30772-00100, Kenya
| | - Joel Lutomiah
- Hemorrhagic Fever Unit, Kenya Medical Research Institute (KEMRI), Center for Virus Research, Nairobi, P.O. Box 62000-00200, Kenya
| | - Simon Muriu
- Department of Biological Sciences, Pwani University Bioscience Centre (PUBREC), Kilifi, P.O Box 230-80100, Kenya
| | - Joseph Nzovu
- Vector Biology Unit, Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Research Coast, Kilifi, P.O. Box 230-80100, Kenya
| | - Rosemary Sang
- Hemorrhagic Fever Unit, Kenya Medical Research Institute (KEMRI), Center for Virus Research, Nairobi, P.O. Box 62000-00200, Kenya
| | - Joseph Mwangangi
- Vector Biology Unit, Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Research Coast, Kilifi, P.O. Box 230-80100, Kenya
- Kenya Medical Research Institute (KEMRI), Center for Vector Disease Control, Kwale, Kenya
| | - Charles Mbogo
- Vector Biology Unit, Kenya Medical Research Institute (KEMRI), Center for Geographic Medicine Research Coast, Kilifi, P.O. Box 230-80100, Kenya
- KEMRI-Wellcome Trust Research Programme, Nairobi, P.O. Box 43640-00100, Kenya
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Tchouassi DP, Jacob JW, Ogola EO, Sang R, Torto B. Aedes vector-host olfactory interactions in sylvatic and domestic dengue transmission environments. Proc Biol Sci 2019; 286:20192136. [PMID: 31690238 PMCID: PMC6842850 DOI: 10.1098/rspb.2019.2136] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 10/17/2019] [Indexed: 01/04/2023] Open
Abstract
Interactions between Aedes (Stegomyia) species and non-human primate (NHP) and human hosts govern the transmission of the pathogens, dengue, zika, yellow fever and chikungunya viruses. Little is known about Aedes mosquito olfactory interactions with these hosts in the domestic and sylvatic cycles where these viruses circulate. Here, we explore how the different host-derived skin odours influence Aedes mosquito responses in these two environments. In field assays, we show that the cyclic ketone cyclohexanone is a signature cue for Aedes mosquitoes to detect the NHP baboon, sykes and vervet, whereas for humans, it is the unsaturated aliphatic keto-analogue 6-methyl-5-hepten-2-one (sulcatone). We find that in the sylvatic environment, CO2-baited traps combined with either cyclohexanone or sulcatone increased trap catches of Aedes mosquitoes compared to traps either baited with CO2 alone or CO2 combined with NHP- or human-derived crude skin odours. In the domestic environment, each of these odourants and crude human skin odours increased Aedes aegypti catches in CO2-baited traps. These results expand our knowledge on the role of host odours in the ecologies of Aedes mosquitoes, and the likelihood of associated spread of pathogens between primates and humans. Both cyclohexanone and sulcatone have potential practical applications as lures for monitoring Aedes disease vectors.
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Affiliation(s)
- David P. Tchouassi
- International Centre of Insect Physiology and Ecology, PO Box 30772-00100, Nairobi, Kenya
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Matowo NS, Abbasi S, Munhenga G, Tanner M, Mapua SA, Oullo D, Koekemoer LL, Kaindoa E, Ngowo HS, Coetzee M, Utzinger J, Okumu FO. Fine-scale spatial and temporal variations in insecticide resistance in Culex pipiens complex mosquitoes in rural south-eastern Tanzania. Parasit Vectors 2019; 12:413. [PMID: 31443737 PMCID: PMC6708135 DOI: 10.1186/s13071-019-3676-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 08/19/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Culex mosquitoes cause considerable biting nuisance and sporadic transmission of arboviral and filarial diseases. METHODS Using standard World Health Organization procedures, insecticide resistance profiles and underlying mechanisms were investigated during dry and wet seasons of 2015 and 2016 in Culex pipiens complex from three neighbouring administrative wards in Ulanga District, Tanzania. Synergist tests with piperonyl butoxide, diethyl maleate, and triphenyl phosphate, were employed to investigate mechanisms of the observed resistance phenotypes. Proportional biting densities of Culex species, relative to other taxa, were determined from indoor surveillance data collected in 2012, 2013, and 2015. RESULTS Insecticide resistance varied significantly between wards and seasons. For example, female mosquitoes in one ward were susceptible to bendiocarb and fenitrothion in the wet season, but resistant during the dry season, while in neighbouring ward, the mosquitoes were fully susceptible to these pesticides in both seasons. Similar variations occurred against bendiocarb, DDT, deltamethrin, and lambda-cyhalothrin. Surprisingly, with the exception of one ward in the wet season, the Culex populations were susceptible to permethrin, commonly used on bednets in the area. No insecticide resistance was observed against the organophosphates, pirimiphos-methyl and malathion, except for one incident of reduced susceptibility in the dry season. Synergist assays revealed possible involvement of monooxygenases, esterases, and glutathione S-transferase in pyrethroid and DDT resistance. Morphology-based identification and molecular assays of adult Culex revealed that 94% were Cx. pipiens complex, of which 81% were Cx. quinquefasciatus, 2% Cx. pipiens, and 3% hybrids. About 14% of the specimens were non-amplified during molecular identifications. Female adults collected indoors were 100% Cx. pipiens complex, and constituted 79% of the overall biting risk. CONCLUSIONS The Cx. pipiens complex constituted the greatest biting nuisance inside people's houses, and showed resistance to most public health insecticides possible. Resistance varied at a fine geographical scale, between adjacent wards, and seasons, which warrants some modifications to current insecticide resistance monitoring strategies. Resistance phenotypes are partly mediated by metabolic mechanisms, but require further evaluation through biochemical and molecular techniques. The high densities and resistance in Culex could negatively influence the acceptability of other interventions such as those used against malaria mosquitoes.
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Affiliation(s)
- Nancy S. Matowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Said Abbasi
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Givemore Munhenga
- Wits Research Institute for Malaria, Wits/SAMRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Salum A. Mapua
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - David Oullo
- US Army Medical Research Directorate-Africa, Kisumu, Kenya
| | - Lizette L. Koekemoer
- Wits Research Institute for Malaria, Wits/SAMRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Emanuel Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Halfan S. Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Maureen Coetzee
- Wits Research Institute for Malaria, Wits/SAMRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Fredros O. Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Nyaruaba R, Mwaliko C, Mwau M, Mousa S, Wei H. Arboviruses in the East African Community partner states: a review of medically important mosquito-borne Arboviruses. Pathog Glob Health 2019; 113:209-228. [PMID: 31664886 PMCID: PMC6882432 DOI: 10.1080/20477724.2019.1678939] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mosquito-borne diseases, including arbovirus-related diseases, make up a large proportion of infectious disease cases worldwide, causing a serious global public health burden with over 700,000 deaths annually. Mosquito-borne arbovirus outbreaks can range from global to regional. In the East African Community (EAC) region, these viruses have caused a series of emerging and reemerging infectious disease outbreaks. Member states in the EAC share a lot in common including regional trade and transport, some of the factors highlighted to be the cause of mosquito-borne arbovirus disease outbreaks worldwide. In this review, characteristics of 24 mosquito-borne arboviruses indigenous to the EAC are reviewed, including lesser or poorly understood viruses, like Batai virus (BATV) and Ndumu virus (NDUV), which may escape their origins under perfect conditions to establish a foothold in new geographical locations. Factors that may influence the future spread of these viruses within the EAC are addressed. With the continued development observed in the EAC, strategies should be developed by the Community in improving mosquito and mosquito-borne arbovirus surveillance to prevent future outbreaks.
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Affiliation(s)
- Raphael Nyaruaba
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
- International college, University of Chinese Academy of Sciences, Beijing, China
| | - Caroline Mwaliko
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
- International college, University of Chinese Academy of Sciences, Beijing, China
| | - Matilu Mwau
- Center for Infectious and Parasitic Diseases Control Research, Kenya Medical Research Institute, Busia, Kenya
| | - Samar Mousa
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
- International college, University of Chinese Academy of Sciences, Beijing, China
| | - Hongping Wei
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei, China
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Karungu S, Atoni E, Ogalo J, Mwaliko C, Agwanda B, Yuan Z, Hu X. Mosquitoes of Etiological Concern in Kenya and Possible Control Strategies. INSECTS 2019; 10:E173. [PMID: 31208124 PMCID: PMC6627689 DOI: 10.3390/insects10060173] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 12/21/2022]
Abstract
Kenya is among the most affected tropical countries with pathogen transmitting Culicidae vectors. For decades, insect vectors have contributed to the emergence and distribution of viral and parasitic pathogens. Outbreaks and diseases have a great impact on a country's economy, as resources that would otherwise be used for developmental projects are redirected to curb hospitalization cases and manage outbreaks. Infected invasive mosquito species have been shown to increasingly cross both local and global boarders due to the presence of increased environmental changes, trade, and tourism. In Kenya, there have been several mosquito-borne disease outbreaks such as the recent outbreaks along the coast of Kenya, involving chikungunya and dengue. This certainly calls for the implementation of strategies aimed at strengthening integrated vector management programs. In this review, we look at mosquitoes of public health concern in Kenya, while highlighting the pathogens they have been linked with over the years and across various regions. In addition, the major strategies that have previously been used in mosquito control and what more could be done to reduce or combat the menace caused by these hematophagous vectors are presented.
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Affiliation(s)
- Samuel Karungu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Evans Atoni
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Joseph Ogalo
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Caroline Mwaliko
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Bernard Agwanda
- Mammalogy Section, National Museum of Kenya, P.O. Box 40658, Nairobi 00100, Kenya.
| | - Zhiming Yuan
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Xiaomin Hu
- Key Laboratory of Special Pathogens and Biosafety, Center for Emerging Infectious Diseases, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
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Ondiba IM, Oyieke FA, Athinya DK, Nyamongo IK, Estambale BBA. Larval species diversity, seasonal occurrence and larval habitat preference of mosquitoes transmitting Rift Valley fever and malaria in Baringo County, Kenya. Parasit Vectors 2019; 12:295. [PMID: 31186055 PMCID: PMC6560760 DOI: 10.1186/s13071-019-3557-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 06/06/2019] [Indexed: 01/19/2023] Open
Abstract
Background Baseline information that is essential for determining the areas to target with larval control includes estimates of vector diversity and larval habitat preferences. Due to a lack of such information in Baringo County, Kenya, this study assessed species diversity and larval habitat preference of potential mosquito vectors of Rift Valley fever (RVF) and malaria. Methods Mosquito larvae were sampled from nine types of larval habitats and were identified morphologically. Species diversity was estimated by the Shannon’s diversity index while larval habitat preference by RVF and malaria vectors was determined by ANOVA. Results A total of 7724 immature mosquitoes comprising 17 species belonging to four genera, namely Anopheles, Culex, Aedes and Mansonia, were identified. Among the 17 species, three Anopheles species are responsible for malaria transmission: An. gambiae (s.l.), An. funestus (s.l.) and An. pharoensis. Rift Valley fever vectors included Mansonia spp. and Culex spp. The highest Shannon's diversity index was observed during the cold dry season (H = 2.487) and in the highland zone (H = 2.539) while the lowest diversity was recorded during the long rain season (H = 2.354) and in the riverine zone (H = 2.085). Ditches had the highest mean number of Anopheles larvae (16.6 larvae per sample) followed by swamp (12.4) and seasonal riverbed (10.7). Water pit and water pan had low mean numbers of Anopheles larvae (1.4 and 1.8, respectively) but relatively high mean numbers of culicines (16.9 and 13.7, respectively). Concrete tank was the least sampled type of habitat but had highest mean number of culicine larvae (333.7 l) followed distantly by water spring (38.9) and swamp (23.5). Overall, larval habitats were significantly different in terms of larval density (F(8,334) = 2.090, P = 0.036). Conclusions To our knowledge, the present study reports culicine larval species diversity in Baringo for the first time and the most preferred habitats were concrete tanks, water springs and swamps. Habitats preferred by Anopheles were mainly riverbed pools, ditches and swamps. Environmental management targeting the habitats most preferred by potential vectors can be part of integrated vector control in Baringo, especially during dry seasons.
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Tchouassi DP, Muturi EJ, Arum SO, Kim CH, Fields CJ, Torto B. Host species and site of collection shape the microbiota of Rift Valley fever vectors in Kenya. PLoS Negl Trop Dis 2019; 13:e0007361. [PMID: 31173595 PMCID: PMC6584011 DOI: 10.1371/journal.pntd.0007361] [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: 12/03/2018] [Revised: 06/19/2019] [Accepted: 04/04/2019] [Indexed: 12/14/2022] Open
Abstract
The composition and structure of microbial communities associated with mosquitoes remain poorly understood despite their important role in host biology and potential to be harnessed as novel strategies for mosquito-borne disease control. We employed MiSeq sequencing of the 16S rRNA gene amplicons to characterize the bacterial flora of field-collected populations of Aedes mcintoshi and Aedes ochraceus, the primary vectors of Rift Valley fever (RVF) virus in Kenya. Proteobacteria (53.5%), Firmicutes (22.0%) and Actinobacteria (10.0%) were the most abundant bacterial phyla accounting for 85.5% of the total sequences. Non-metric multi-dimensional scaling plots based on Bray-Curtis dissimilarities revealed a clear grouping of the samples by mosquito species, indicating that the two mosquito species harbored distinct microbial communities. Microbial diversity, richness and composition was strongly influenced by the site of mosquito collection and overall, Ae. ochraceus had significantly higher microbial diversity and richness than Ae. mcintoshi. Our findings suggest that host species and site of collection are important determinants of bacterial community composition and diversity in RVF virus vectors and these differences likely contribute to the spatio-temporal transmission dynamics of RVF virus. Knowledge of the microbial communities associated with disease vectors can be exploited for symbiotic control of vector-borne diseases. Here, we characterized and compared the bacterial communities of field-caught populations of Aedes mcintoshi and Aedes ochraceus, the primary vectors of Rift Valley fever (RVF) virus in Kenya. We show that the two mosquito species harbor distinct microbial communities whose diversity and richness are heavily influenced by the site of collection. Because some bacterial species are known to influence vector susceptibility to pathogens, differences in bacterial communities between the two mosquito species is likely one of the primary factors accounting for the spatial and temporal variation in transmission dynamics of RVF virus.
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Affiliation(s)
- David P. Tchouassi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- * E-mail:
| | - Ephantus J. Muturi
- Crop Bioprotection Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois, United States of America
| | - Samwel O. Arum
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Chang-Hyun Kim
- Illinois Natural History Survey, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America
| | - Christopher J. Fields
- High Performance Computing in Biology (HPCBio), Roy J Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Illinois, United States of America
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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Grossi-Soyster EN, Lee J, King CH, LaBeaud AD. The influence of raw milk exposures on Rift Valley fever virus transmission. PLoS Negl Trop Dis 2019; 13:e0007258. [PMID: 30893298 PMCID: PMC6443189 DOI: 10.1371/journal.pntd.0007258] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/01/2019] [Accepted: 02/23/2019] [Indexed: 02/07/2023] Open
Abstract
Rift Valley fever virus (RVFV) is a zoonotic phlebovirus that can be transmitted to humans or livestock by mosquitoes or through direct contact with contaminated bodily fluids and tissues. Exposure to bodily fluids and tissues varies by types of behaviors engaged for occupational tasks, homestead responsibilities, or use in dietary or therapeutic capacities. While previous studies have included milk exposures in their analyses, their primary focus on livestock exposures has been on animal handling, breeding, and slaughter. We analyzed data from multiple field surveys in Kenya with the aim of associating RVFV infection to raw milk exposures from common animal species. Of those with evidence of prior RVFV infection by serology (n = 267), 77.2% engaged in milking livestock compared to 32.0% for 3,956 co-local seronegative individuals (p < 0.001), and 86.5% of seropositive individuals consumed raw milk compared to 33.4% seronegative individuals (p < 0.001). Individuals who milked and also consumed raw milk had greater odds of RVFV exposure than individuals whose only contact to raw milk was through milking. Increased risks were associated with exposure to milk sourced from cows (p < 0.001), sheep (p < 0.001), and goats (p < 0.001), but not camels (p = 0.98 for consuming, p = 0.21 for milking). Our data suggest that exposure to raw milk may contribute to a significant number of cases of RVFV, especially during outbreaks and in endemic areas, and that some animal species may be associated with a higher risk for RVFV exposure. Livestock trade is regulated to limit RVFV spread from endemic areas, yet further interventions designed to fully understand the risk of RVFV exposure from raw milk are imperative.
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Affiliation(s)
- Elysse N. Grossi-Soyster
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA, United States of America
- * E-mail:
| | - Justin Lee
- Quantitative Sciences Unit, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Charles H. King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, United States of America
| | - A. Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA, United States of America
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Jones RT, Tusting LS, Smith HMP, Segbaya S, Macdonald MB, Bangs MJ, Logan JG. The impact of industrial activities on vector-borne disease transmission. Acta Trop 2018; 188:142-151. [PMID: 30165072 DOI: 10.1016/j.actatropica.2018.08.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/25/2018] [Accepted: 08/25/2018] [Indexed: 10/28/2022]
Abstract
Industrial activities have produced profound changes in the natural environment, including the mass removal of trees, fragmentation of habitats, and creation of larval mosquito breeding sites, that have allowed the vectors of disease pathogens to thrive. We conducted a review of the literature to assess the impact of industrial activities on vector-borne disease transmission. Our study shows that industrial activities may be coupled with significant changes to human demographics that can potentially increase contact between pathogens, vectors and hosts, and produce a shift of parasites and susceptible populations between low and high disease endemic areas. Indeed, where vector-borne diseases and industrial activities intersect, large numbers of potentially immunologically naïve people may be exposed to infection and lack the knowledge and means to protect themselves from infection. Such areas are typically associated with inadequate access to quality health care, thus allowing industrial development and production sites to become important foci of transmission. The altered local vector ecologies, and the changes in disease dynamics that changes affect, create challenges for under-resourced health care and vector-control systems.
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Affiliation(s)
- Robert T Jones
- ARCTEC, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Lucy S Tusting
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Hugh M P Smith
- ARCTEC, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | | | - Michael J Bangs
- International SOS, Ltd., Papua Province, Indonesia; International SOS, Ltd., Lualaba Province, Democratic Republic of Congo
| | - James G Logan
- ARCTEC, London School of Hygiene & Tropical Medicine, London, United Kingdom; Department of Disease Control, London School of Hygiene & Tropical Medicine, United Kingdom
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Yu F, Adungo F, Konongoi SL, Inoue S, Sang R, Ashur S, Kwallah AO, Uchida L, Buerano CC, Mwau M, Zha Y, Nie Y, Morita K. Comparison of enzyme-linked immunosorbent assay systems using rift valley fever virus nucleocapsid protein and inactivated virus as antigens. Virol J 2018; 15:178. [PMID: 30466469 PMCID: PMC6249750 DOI: 10.1186/s12985-018-1071-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/28/2018] [Indexed: 11/25/2022] Open
Abstract
Background Rift Valley Fever (RVF) is a mosquito-borne viral zoonosis. To detect RVF virus (RVFV) infection, indirect immunoglobulin G (IgG) and immunoglobulin M (IgM) enzyme linked immunosorbent assays (ELISAs) which utilize recombinant RVFV nucleocapsid (RVFV-N) protein as assay antigen, have reportedly been used, however, there is still a need to develop more sensitive and specific methods of detection. Methods RVFV-N protein was expressed in Escherichia coli (E. coli) and purified by histidine-tag based affinity chromatography. This recombinant RVFV-N (rRVFV-N) protein was then used as antigen to develop an IgG sandwich ELISA and IgM capture ELISAs for human sera. Ninety six serum samples collected from healthy volunteers during the RVF surveillance programme in Kenya in 2013, and 93 serum samples collected from RVF-suspected patients during the 2006–2007 RVF outbreak in Kenya were used respectively, to evaluate the newly established rRVFV-N protein-based IgG sandwich ELISA and IgM capture ELISA systems in comparison with the inactivated virus-based ELISA systems. Results rRVFV-N protein-based-IgG sandwich ELISA and IgM capture ELISA for human sera were established. Both the new ELISA systems were in 100% concordance with the inactivated virus-based ELISA systems, with a sensitivity and specificity of 100%. Conclusions Recombinant RVFV-N is a safe and affordable antigen for RVF diagnosis. Our rRVFV-N-based ELISA systems are safe and reliable tools for diagnosis of RVFV infection in humans and especially useful in large-scale epidemiological investigation and for application in developing countries.
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Affiliation(s)
- Fuxun Yu
- Guizhou Provincial People's Hospital, Medical College, Guizhou University, No. 83 Zhongshan Dong Road, Guiyang, 550002, Guizhou Province, China
| | - Ferdinard Adungo
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12- 4, Sakamoto, Nagasaki, 852-8523, Japan.,Kenya Medical Research Institute, Nairobi, Kenya
| | | | - Shingo Inoue
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12- 4, Sakamoto, Nagasaki, 852-8523, Japan
| | | | - Salame Ashur
- Kenya Medical Research Institute, Nairobi, Kenya
| | | | - Leo Uchida
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12- 4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Corazon C Buerano
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12- 4, Sakamoto, Nagasaki, 852-8523, Japan
| | - Matilu Mwau
- Kenya Medical Research Institute, Nairobi, Kenya
| | - Yan Zha
- Guizhou Provincial People's Hospital, Medical College, Guizhou University, No. 83 Zhongshan Dong Road, Guiyang, 550002, Guizhou Province, China
| | - Yingjie Nie
- Guizhou Provincial People's Hospital, Medical College, Guizhou University, No. 83 Zhongshan Dong Road, Guiyang, 550002, Guizhou Province, China.
| | - Kouichi Morita
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12- 4, Sakamoto, Nagasaki, 852-8523, Japan.
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Ajamma YU, Onchuru TO, Ouso DO, Omondi D, Masiga DK, Villinger J. Vertical transmission of naturally occurring Bunyamwera and insect-specific flavivirus infections in mosquitoes from islands and mainland shores of Lakes Victoria and Baringo in Kenya. PLoS Negl Trop Dis 2018; 12:e0006949. [PMID: 30452443 PMCID: PMC6287884 DOI: 10.1371/journal.pntd.0006949] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 12/10/2018] [Accepted: 10/26/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Many arboviruses transmitted by mosquitoes have been implicated as causative agents of both human and animal illnesses in East Africa. Although epidemics of arboviral emerging infectious diseases have risen in frequency in recent years, the extent to which mosquitoes maintain pathogens in circulation during inter-epidemic periods is still poorly understood. This study aimed to investigate whether arboviruses may be maintained by vertical transmission via immature life stages of different mosquito vector species. METHODOLOGY We collected immature mosquitoes (egg, larva, pupa) on the shores and islands of Lake Baringo and Lake Victoria in western Kenya and reared them to adults. Mosquito pools (≤25 specimens/pool) of each species were screened for mosquito-borne viruses by high-resolution melting analysis and sequencing of multiplex PCR products of genus-specific primers (alphaviruses, flaviviruses, phleboviruses and Bunyamwera-group orthobunyaviruses). We further confirmed positive samples by culturing in baby hamster kidney and Aedes mosquito cell lines and re-sequencing. PRINCIPAL FINDINGS Culex univittatus (2/31pools) and Anopheles gambiae (1/77 pools) from the Lake Victoria region were positive for Bunyamwera virus, a pathogenic virus that is of public health concern. In addition, Aedes aegypti (3/50), Aedes luteocephalus (3/13), Aedes spp. (2/15), and Culex pipiens (1/140) pools were positive for Aedes flaviviruses at Lake Victoria, whereas at Lake Baringo, three pools of An. gambiae mosquitoes were positive for Anopheles flavivirus. These insect-specific flaviviruses (ISFVs), which are presumably non-pathogenic to vertebrates, were found in known medically important arbovirus and malaria vectors. CONCLUSIONS Our results suggest that not only ISFVs, but also a pathogenic arbovirus, are naturally maintained within mosquito populations by vertical transmission, even in the absence of vertebrate hosts. Therefore, virus and vector surveillance, even during inter-epidemics, and the study of vector-arbovirus-ISFV interactions, may aid in identifying arbovirus transmission risks, with the potential to inform control strategies that lead to disease prevention.
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Affiliation(s)
| | - Thomas Ogao Onchuru
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Department of Evolutionary Ecology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
| | - Daniel O. Ouso
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - David Omondi
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
- Biochemistry and Molecular Biology Department, Egerton University, Egerton, Kenya
| | - Daniel K. Masiga
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
| | - Jandouwe Villinger
- International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya
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48
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Alhaji NB, Babalobi OO, Wungak Y, Ularamu HG. Participatory survey of Rift Valley fever in nomadic pastoral communities of North-central Nigeria: The associated risk pathways and factors. PLoS Negl Trop Dis 2018; 12:e0006858. [PMID: 30376568 PMCID: PMC6207297 DOI: 10.1371/journal.pntd.0006858] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 09/18/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Rift Valley fever (RVF) is an emerging neglected mosquito-borne viral zoonotic disease of domestic animals and humans, with potential for global expansion. The objectives of this study were: to assess perceived relative burden and seasonality of RVF in nomadic cattle herds and validate the burden with sero-prevalence impact; and assess perceived risk factors associated with the disease and risk pathways for RVF virus in nomadic pastoral herds of North-central Nigeria using pastoralists' existing veterinary knowledge. METHODS Participatory Epidemiology (PE) survey was conducted in Fulani nomadic pastoral communities domiciled in Niger State between January and December 2015. A cross-sectional sero-prevalence investigation was also carried out in nomadic pastoral cattle herds to validate outcomes of PE. A total of nine nomadic pastoral communities were purposively selected for qualitative impact assessment using Participatory Rural Appraisal tools, while 97 cattle randomly sampled from 15 purposively selected nomadic herds and had their sera analyzed using c-ELISA. Kendall's Coefficient of Concordance W statistics and OpenEpi 2.3.1 were used for statistical analyses. RESULTS Mean proportional piles (relative burden) of RVF (Gabi-gabiF) was 8.3%, and nomads agreement on the burden was strong (W = 0.6855) and statistically significant (P<0.001). This was validated by 11.3% (11/97; 95% CI: 6.1-18.9) sero-positivity (quantitative impact). Mean matrix scores of prominent clinical signs associated with RVF were fever (3.1), anorexia (2.1), abortion (4.1), nasal discharge (3.3), neurological disorder (8.4), diarrhoea (3.2), and sudden death (4.4), with strong agreement (W = 0.6687) and statistically significant (p<0.001). Mean proportional piles of pastoralists' perceived risk factors identified to influenced RVF occurrence were: availability of mosquitoes (18 piles, 17.6%), high cattle density (16 piles, 15.9%) and high rainfall (12 piles, 12.2%). Agreement on the risk factors was strong (W = 0.8372) and statistically significant (p<0.01). Mean matrix scores for the Entry pathway of RVF virus into the nomadic pastoral herds were: presence of RVFV infected mosquitoes (tiny biting flies) (7.9), presence of infected cattle in herds (8.4), and contacts of herd with infected wild animals at grazing (10.1). Mean matrix scores for the Spread pathway of RVF virus in herds were bites of infected mosquitoes (5.1), contacts with infected aborted fetuses/fluids (7.8), and contaminated pasture with aborted fetuses/fluids (9.7). Agreement on risk pathways was strong (W = 0.6922) and statistically significant (p<0.03). Key informants scored RVF to occurred more in Damina or late rainy season (5.3), followed by Kaka or early dry season (3.3), with strong agreement (W = 0.8719) and statistically significant (P<0.01). This study highlighted the significant existing knowledge level about RVF contained in nomadic pastoralists. CONCLUSIONS The use of PE approach is needful in active surveillance of livestock diseases in pastoral communities domiciled in highly remote areas. RVF surveillance system, control and prevention programmes that take the identified risk factors and pathways into consideration will be beneficial to the livestock industry in Nigeria, and indeed Africa. An 'OneHealth' approach is needed to improve efficiency of RVF research, surveillance, prevention and control systems, so as to assure food security and public health in developing countries.
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Affiliation(s)
- Nma Bida Alhaji
- Public Health and Epidemiology Department, Niger State Ministry of Livestock and Fisheries, Minna, Nigeria
- Department of Veterinary Public Health and Preventive Medicine, University of Ibadan, Ibadan, Nigeria
- * E-mail:
| | - Olutayo Olajide Babalobi
- Department of Veterinary Public Health and Preventive Medicine, University of Ibadan, Ibadan, Nigeria
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49
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Tshilenge GM, Dundon WG, De Nardi M, Mulumba Mfumu LK, Rweyemamu M, Kayembe-Ntumba JM, Masumu J. Seroprevalence of Rift Valley fever virus in cattle in the Democratic Republic of the Congo. Trop Anim Health Prod 2018; 51:537-543. [PMID: 30350160 DOI: 10.1007/s11250-018-1721-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 09/30/2018] [Indexed: 01/08/2023]
Abstract
This study aimed at assessing the serological and virological status of Rift Valley fever virus (RVFV) in cattle from four climatically diverse zones of the Democratic Republic of the Congo (DRC). A total of 1675 sera samples collected between 2014 and 2015 from cattle without clinical manifestation of RVF infection were tested using competitive and capture enzyme ELISA to detect both IgG and IgM. RT-PCR was used for the detection of nucleic acid of RVFV. Out of the 1675 cattle sera tested, 203 were found to be IgG-positive, giving an overall true seroprevalence of 12.37% (95% CI 10.86-14.05). This seroprevalence varied between the four zones with a seroprevalence of 16.16% (95% CI 12.86-20.12), 14.70% (95% CI 11.72-18.29), 10.82% (95% CI 7.19-14.19), and 7.34% (95% CI 5.13-10.41) recorded in cattle sampled in the mountainous, humid savannah, dry savannah, and forest zones, respectively (p < 0.05, χ2 = 17.26). A higher true seroprevalence of 14.58% (95% CI 9.3-22.13) was found in animals aged 1 year compared to 10.43% (95% CI 8.12-13.30) and 13.16% (95% CI 11.19-15.42) in groups aged between 2-3 and > 3 years, respectively, although the difference was not statistically significant (p > 0.05, χ2 = 2.95). Similarly, no statistically significant difference (p > 0.05, χ2 = 0.04) was found between the sexes of the animals. Among the IgG-positive samples screened for anti-RVFV IgM, only 1.47% (3/203) was IgM-positive. One of the IgM-positive samples was positive by RT-PCR. These findings reveal country-wide distribution of RVF in the DRC for the first time.
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Affiliation(s)
- Georges Mbuyi Tshilenge
- Faculty of Veterinary Medicine, University of Kinshasa, University Street, P.O. Box 117, Kinshasa XI, Democratic Republic of the Congo. .,Central Veterinary Laboratory, Wangata Street, Gombe, P.O. Box 8842, Kinshasa, Democratic Republic of the Congo.
| | - William G Dundon
- Animal Production and Health Laboratory, Joint FAO/AIEA, Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Application, International Atomic Energy Agency, Wagramer Strasse 5, P.O. Box 100, 1400, Vienna, Austria
| | | | - Leopold K Mulumba Mfumu
- Faculty of Veterinary Medicine, University of Kinshasa, University Street, P.O. Box 117, Kinshasa XI, Democratic Republic of the Congo
| | - Mark Rweyemamu
- Southern African Centre for Infectious Disease Surveillance, Sokoïne University of Agriculture, Chuo Kikuu, P.O. Box 3297, Morogoro, Tanzania
| | - Jean-Marie Kayembe-Ntumba
- Faculty of Medicine, University of Kinshasa, University Street, P.O. Box 117, Kinshasa XI, Democratic Republic of the Congo
| | - Justin Masumu
- Central Veterinary Laboratory, Wangata Street, Gombe, P.O. Box 8842, Kinshasa, Democratic Republic of the Congo.,Faculty of Veterinary Medicine, National Pedagogic University, Matadi/Liberation Street, Ngaliema, P.O. Box 8815, Kinshasa, Democratic Republic of the Congo.,National Institute for Biomedical Research, 5345 Huilerie Street, Gombe, Kinshasa, Democratic Republic of the Congo
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50
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Jacob JW, Tchouassi DP, Lagat ZO, Mathenge EM, Mweresa CK, Torto B. Independent and interactive effect of plant- and mammalian- based odors on the response of the malaria vector, Anopheles gambiae. Acta Trop 2018; 185:98-106. [PMID: 29709631 DOI: 10.1016/j.actatropica.2018.04.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/25/2018] [Accepted: 04/25/2018] [Indexed: 12/22/2022]
Abstract
Several studies have shown that odors of plant and animal origin can be developed into lures for use in surveillance of mosquito vectors of infectious diseases. However, the effect of combining plant- and mammalian-derived odors into an improved lure for monitoring both nectar- and blood-seeking mosquito populations in traps is yet to be explored. Here we used both laboratory dual choice olfactometer and field assays to investigate responses of the malaria vector, Anopheles gambiae, to plant- and mammalian-derived compounds and a combined blend derived from these two odor sources. Using subtractive bioassays in dual choice olfactometer we show that a 3-component terpenoid plant-derived blend comprising (E)-linalool oxide, β-pinene, β-ocimene was more attractive to females of An. gambiae than (E)-linalool oxide only (previously found attractive in field trials) and addition of limonene to this blend antagonized its attractiveness. Likewise, a mammalian-derived lure comprising the aldehydes heptanal, octanal, nonanal and decanal, was more preferred than (E)-linalool oxide. Surprisingly, combining the plant-derived 3-component blend with the mammalian derived 4-component blend attracted fewer females of An. gambiae than the individual blends in laboratory assays. However, this pattern was not replicated in field trials, where we observed a dose-dependent effect on trap catches while combining both blends with significantly improved trap catches at higher doses. The observed dose-dependent attractiveness for An. gambiae has practical implication in the design of vector control strategies involving kairomones from plant- and mammalian-based sources.
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Affiliation(s)
- Juliah W Jacob
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya
| | - David P Tchouassi
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya
| | - Zipporah O Lagat
- School of Biological Sciences, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya
| | - Evan M Mathenge
- Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Collins K Mweresa
- Department of Biological Sciences, Jaramogi Oginga Odinga University of Science and Technology, P.O. Box 210-40601, Bondo, Kenya
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology, P.O. Box 30772-00100, Nairobi, Kenya.
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