1
|
Balaraman V, Indran SV, Kim IJ, Trujillo JD, Meekins DA, Shivanna V, Zajac MD, Urbaniak K, Morozov I, Sunwoo SY, Faburay B, Osterrieder K, Gaudreault NN, Wilson WC, Richt JA. Rift Valley Fever Phlebovirus Reassortment Study in Sheep. Viruses 2024; 16:880. [PMID: 38932172 PMCID: PMC11209395 DOI: 10.3390/v16060880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/21/2024] [Accepted: 05/26/2024] [Indexed: 06/28/2024] Open
Abstract
Rift Valley fever (RVF) in ungulates and humans is caused by a mosquito-borne RVF phlebovirus (RVFV). Live attenuated vaccines are used in livestock (sheep and cattle) to control RVF in endemic regions during outbreaks. The ability of two or more different RVFV strains to reassort when co-infecting a host cell is a significant veterinary and public health concern due to the potential emergence of newly reassorted viruses, since reassortment of RVFVs has been documented in nature and in experimental infection studies. Due to the very limited information regarding the frequency and dynamics of RVFV reassortment, we evaluated the efficiency of RVFV reassortment in sheep, a natural host for this zoonotic pathogen. Co-infection experiments were performed, first in vitro in sheep-derived cells, and subsequently in vivo in sheep. Two RVFV co-infection groups were evaluated: group I consisted of co-infection with two wild-type (WT) RVFV strains, Kenya 128B-15 (Ken06) and Saudi Arabia SA01-1322 (SA01), while group II consisted of co-infection with the live attenuated virus (LAV) vaccine strain MP-12 and a WT strain, Ken06. In the in vitro experiments, the virus supernatants were collected 24 h post-infection. In the in vivo experiments, clinical signs were monitored, and blood and tissues were collected at various time points up to nine days post-challenge for analyses. Cell culture supernatants and samples from sheep were processed, and plaque-isolated viruses were genotyped to determine reassortment frequency. Our results show that RVFV reassortment is more efficient in co-infected sheep-derived cells compared to co-infected sheep. In vitro, the reassortment frequencies reached 37.9% for the group I co-infected cells and 25.4% for the group II co-infected cells. In contrast, we detected just 1.7% reassortant viruses from group I sheep co-infected with the two WT strains, while no reassortants were detected from group II sheep co-infected with the WT and LAV strains. The results indicate that RVFV reassortment occurs at a lower frequency in vivo in sheep when compared to in vitro conditions in sheep-derived cells. Further studies are needed to better understand the implications of RVFV reassortment in relation to virulence and transmission dynamics in the host and the vector. The knowledge learned from these studies on reassortment is important for understanding the dynamics of RVFV evolution.
Collapse
Affiliation(s)
- Velmurugan Balaraman
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Sabarish V. Indran
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - In Joong Kim
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Jessie D. Trujillo
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - David A. Meekins
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Vinay Shivanna
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Michelle D. Zajac
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
- Foreign Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service, National Bio and Agro-Defense Facility, Manhattan, KS 66505, USA
| | - Kinga Urbaniak
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Igor Morozov
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Sun-Young Sunwoo
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Bonto Faburay
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
- Foreign Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service, National Bio and Agro-Defense Facility, Manhattan, KS 66505, USA
| | - Klaus Osterrieder
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - Natasha N. Gaudreault
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| | - William C. Wilson
- Foreign Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture, Agricultural Research Service, National Bio and Agro-Defense Facility, Manhattan, KS 66505, USA
| | - Juergen A. Richt
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA; (V.B.); (S.V.I.); (J.D.T.); (S.-Y.S.)
| |
Collapse
|
2
|
Trujillo JD, Wilson WC, Craig A, Van den Bergh C, Wang T, Thompson P, Swanepoel R, Morozov I, Richt JA. Rift Valley Fever virus M and L genome segment detection: a comparison of field-deployable reverse transcription insulated isothermal PCR (RT-iiPCR) and laboratory-based multiplex reverse transcription real-time PCR. J Clin Microbiol 2024; 62:e0043023. [PMID: 38305205 PMCID: PMC10935642 DOI: 10.1128/jcm.00430-23] [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: 04/06/2023] [Accepted: 11/21/2023] [Indexed: 02/03/2024] Open
Abstract
Rift Valley Fever phlebovirus (RVFV) is a mosquito-borne zoonotic pathogen that causes major agricultural and public health problems in Africa and the Arabian Peninsula. It is considered a potential agro-bioterrorism agent for which limited countermeasures are available. To address diagnostic needs, here we describe a rapid and sensitive molecular method immediately employable at sites of suspected outbreaks in animals that commonly precede outbreaks in humans. The strategy involves the concurrent detection of two of the three RVFV genome segments (large and medium) using reverse transcription insulated isothermal PCR (RT-iiPCR) performed on a portable, touch screen nucleic acid analyzer, POCKIT. The analytical sensitivity for both the RT-iiPCR and a laboratory-based L and M multiplex reverse transcription real-time PCR assay was estimated at approximately 0.1-3 copies/reaction using synthetic RNA or viral RNA. The diagnostic sensitivity and specificity of detection of RVFV on the POCKIT, determined using sera from sheep and cattle (n = 181) experimentally infected with two strains of RVFV (SA01 and Ken06), were 93.8% and 100% (kappa = 0.93), respectively. Testing of ruminant field sera (n = 193) in two locations in Africa demonstrated 100% diagnostic sensitivity and specificity. We conclude that the POCKIT dual-gene RVFV detection strategy can provide reliable, sensitive, and specific point-of-need viral RNA detection. Moreover, the field detection of RVFV in vectors or susceptible animal species can aid in the surveillance and epidemiological studies to better understand and control RVFV outbreaks. IMPORTANCE The content of this manuscript is of interest to the diverse readership of the Journal of Clinical Microbiology, including research scientists, diagnosticians, healthcare professionals, and policymakers. Rift Valley Fever virus (RVFV) is a zoonotic mosquito-borne pathogen that causes major agricultural and public health problems. Current and most sensitive diagnostic approaches that are molecular-based are performed in highly specialized molecular diagnostic laboratories. To address diagnostic needs, we developed a novel, rapid, and sensitive molecular method using a portable PCR machine, POCKIT, capable of immediate deployment at sites of suspected outbreaks. Here, we demonstrate that field-deployable RVFV detection can provide reliable, sensitive, and specific point-of-need viral RNA detection that could be used for diagnostic investigations and epidemiological studies, and can be performed in the field.
Collapse
Affiliation(s)
- Jessie D. Trujillo
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, Kansas, USA
| | - William C. Wilson
- Foreign Arthropod-Borne Animal Diseases Research Unit (FABADRU), USDA Agricultural Research Service (ARS), Manhattan, Kansas, USA
| | - Anthony Craig
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Vectors and Vector-Borne Diseases Research Programme, Pretoria, South Africa
| | - Carien Van den Bergh
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Vectors and Vector-Borne Diseases Research Programme, Pretoria, South Africa
| | - Thomas Wang
- Research and development, GeneReach USA, Lexington, Massachusetts, USA
| | - Peter Thompson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Robert Swanepoel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Vectors and Vector-Borne Diseases Research Programme, Pretoria, South Africa
| | - Igor Morozov
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, Kansas, USA
| | - Juergen A. Richt
- Center of Excellence for Emerging and Zoonotic Animal Diseases, Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, Kansas, USA
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Vectors and Vector-Borne Diseases Research Programme, Pretoria, South Africa
| |
Collapse
|
3
|
Zimnyakov DA, Alonova MV, Lavrukhin MS, Lyapina AM, Feodorova VA. Polarization- and Chaos-Game-Based Fingerprinting of Molecular Targets of Listeria Monocytogenes Vaccine and Fully Virulent Strains. Curr Issues Mol Biol 2023; 45:10056-10078. [PMID: 38132474 PMCID: PMC10742786 DOI: 10.3390/cimb45120628] [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: 10/26/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023] Open
Abstract
Two approaches to the synthesis of 2D binary identifiers ("fingerprints") of DNA-associated symbol sequences are considered in this paper. One of these approaches is based on the simulation of polarization-dependent diffraction patterns formed by reading the modeled DNA-associated 2D phase-modulating structures with a coherent light beam. In this case, 2D binarized distributions of close-to-circular extreme polarization states are applied as fingerprints of analyzed nucleotide sequences. The second approach is based on the transformation of the DNA-associated chaos game representation (CGR) maps into finite-dimensional binary matrices. In both cases, the differences between the structures of the analyzed and reference symbol sequences are quantified by calculating the correlation coefficient of the synthesized binary matrices. A comparison of the approaches under consideration is carried out using symbol sequences corresponding to nucleotide sequences of the hly gene from the vaccine and wild-type strains of Listeria monocytogenes as the analyzed objects. These strains differ in terms of the number of substituted nucleotides in relation to the vaccine strain selected as a reference. The results of the performed analysis allow us to conclude that the identification of structural differences in the DNA-associated symbolic sequences is significantly more efficient when using the binary distributions of close-to-circular extreme polarization states. The approach given can be applicable for genetic differentiation immunized from vaccinated animals (DIVA).
Collapse
Affiliation(s)
- Dmitry A. Zimnyakov
- Physics Department, Yury Gagarin State Technical University of Saratov, 77 Polytechnicheskaya Str., 410054 Saratov, Russia;
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named after N.I. Vavilov, 335 Sokolovaya Str., 410005 Saratov, Russia; (M.S.L.); (A.M.L.); (V.A.F.)
| | - Marina V. Alonova
- Physics Department, Yury Gagarin State Technical University of Saratov, 77 Polytechnicheskaya Str., 410054 Saratov, Russia;
| | - Maxim S. Lavrukhin
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named after N.I. Vavilov, 335 Sokolovaya Str., 410005 Saratov, Russia; (M.S.L.); (A.M.L.); (V.A.F.)
| | - Anna M. Lyapina
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named after N.I. Vavilov, 335 Sokolovaya Str., 410005 Saratov, Russia; (M.S.L.); (A.M.L.); (V.A.F.)
| | - Valentina A. Feodorova
- Laboratory for Fundamental and Applied Research, Saratov State University of Genetics, Biotechnology and Engineering Named after N.I. Vavilov, 335 Sokolovaya Str., 410005 Saratov, Russia; (M.S.L.); (A.M.L.); (V.A.F.)
- Department for Microbiology and Biotechnology, Saratov State University of Genetics, Biotechnology and Engineering Named after N.I. Vavilov, 335 Sokolovaya Str., 410005 Saratov, Russia
| |
Collapse
|
4
|
Choi Y, Kim Y. Application of multiplex realtime PCR detection for hemorrhagic fever syndrome viruses. J Infect Public Health 2023; 16:1933-1941. [PMID: 37866271 DOI: 10.1016/j.jiph.2023.10.012] [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: 03/30/2023] [Revised: 09/13/2023] [Accepted: 10/05/2023] [Indexed: 10/24/2023] Open
Abstract
BACKGROUND Multiplex real-time PCR is a quick and cost effective method for detection of various gene simultaneously. HFSV (Hemorrhagic Fever Syndrome Virus) is a newly emerging infectious disease because of globalization and climate change. We tried to develop a molecular diagnostic technique for various causative viruses and evaluate its usefulness for improving public health. METHODS Molecular diagnostic test method that qualitatively detects viruses causing viral hemorrhagic fevers hired Taq-Man Real-time RT-PCR technique. The Ct value was experimentally observed three or more times at the RNA concentration before and after the detection limit. After designing a multiplex real-time RT-PCR test for target gene of selected 17 viruses, the detection limit for each target and the presence or absence of cross-reaction and interference reaction were evaluated to determine its availability. RESULTS Six kinds of viruses, including Crimean-Congo hemorrhagic fever virus, Omsk hemorrhagic fever virus, Sabia virus, Chapare virus, Yellow fever virus, and Variola virus (A4L gene, B12R gene), were able to confirm the detection limit of 0.5 copies/μl, and other Ebola virus, Marburg virus, Rift Valley fever virus, Kyasanur Forest disease virus, Junin virus, Guanarito virus, Machupo virus, Chikungunya virus, Hantavirus, Dengue virus types 1-4, and Lassa virus (L gene, GPC gene), and 11 kinds of viruses, the detection limit was confirmed at 5 copies/μl. No cross-reaction or interference between detected genes was observed. CONCLUSION The virus test method developed through this study using multiplex is expected to be used for public health and quarantine as a test method that can be used when a hemorrhagic fever virus of unknown cause is introduced.
Collapse
Affiliation(s)
- Yoonhyuk Choi
- Department of Convergence Engineering, Graduate School of Venture, Hoseo University, Seoul, 06724, South Korea; MDx Center, Diagnosis Division, iNtRON Biotechnology, South Korea
| | - Younghee Kim
- Department of Convergence Engineering, Graduate School of Venture, Hoseo University, Seoul, 06724, South Korea.
| |
Collapse
|
5
|
Jaleta MB, Tefera M, Negussie H, Mulatu T, Berhe T, Belete F, Yalew B, Gizaw O, Dabasa G, Abunna F, Regassa F, Amenu K, Leta S. Entomological survey of the potential vectors of Rift Valley fever virus and absence of detection of the virus genome from the vectors in various niches in the southern half of the Great Rift Valley of Ethiopia. Vet Med Sci 2022; 8:2716-2725. [DOI: 10.1002/vms3.941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Megarsa Bedasa Jaleta
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | - Mehari Tefera
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | - Haileleul Negussie
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | | | - Tsega Berhe
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | - Fasika Belete
- College of Veterinary Medicine and Agriculture Jimma University Jimma Ethiopia
| | - Bekele Yalew
- Animal Health Institute Entomology Unit Sebeta Ethiopia
| | - Oda Gizaw
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | - Golo Dabasa
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | - Fufa Abunna
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | - Fikru Regassa
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
- Ministry of Agriculture Livestock and Fishery Addis Ababa Ethiopia
| | - Kebede Amenu
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| | - Samson Leta
- College of Veterinary Medicine and Agriculture Addis Ababa University Bishoftu Ethiopia
| |
Collapse
|
6
|
van den Bergh C, Thompson PN, Swanepoel R, Almeida APG, Paweska JT, Jansen van Vuren P, Wilson WC, Kemp A, Venter EH. Detection of Rift Valley Fever Virus in Aedes (Aedimorphus) durbanensis, South Africa. Pathogens 2022; 11:pathogens11020125. [PMID: 35215069 PMCID: PMC8879006 DOI: 10.3390/pathogens11020125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/10/2022] [Accepted: 01/18/2022] [Indexed: 12/10/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne, zoonotic phlebovirus-causing disease in domestic ruminants and humans in Africa, the Arabian Peninsula and some Indian Ocean islands. Outbreaks, characterized by abortion storms and a high morbidity rate in newborn animals, occur after heavy and prolonged rainfalls favouring the breeding of mosquitoes. However, the identity of the important mosquito vectors of RVFV is poorly known in most areas. Mosquitoes collected in the Ndumo area of tropical north-eastern KwaZulu-Natal (KZN), South Africa, were tested for RVFV nucleic acid using RT-PCR. The virus was detected in a single pool of unfed Aedes (Aedimorphus) durbanensis, indicating that this seasonally abundant mosquito species could serve as a vector in this area of endemic RVFV circulation. Phylogenetic analysis indicated the identified virus is closely related to two isolates from the earliest outbreaks, which occurred in central South Africa more than 60 years ago, indicating long-term endemicity in the region. Further research is required to understand the eco-epidemiology of RVFV and the vectors responsible for its circulation in the eastern tropical coastal region of southern Africa.
Collapse
Affiliation(s)
- Carien van den Bergh
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa; (R.S.); (E.H.V.)
- Correspondence: ; Tel.: +27-(0)82-300-7406
| | - Peter N. Thompson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria 0002, South Africa;
| | - Robert Swanepoel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa; (R.S.); (E.H.V.)
| | - Antonio P. G. Almeida
- Unidade de Parasitologia Medica, Global Health and Tropical Medicine, Universidade Nova Lisboa, 1365-008 Lisboa, Portugal;
| | - Janusz T. Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa; (J.T.P.); (P.J.v.V.); (A.K.)
- Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Petrus Jansen van Vuren
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa; (J.T.P.); (P.J.v.V.); (A.K.)
- Australian Centre for Disease Preparedness, CSIRO-Health and Biosecurity, Geelong, VIC 3220, Australia
| | - William C. Wilson
- National Bio and Agro-Defense Facility, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS 66502, USA;
| | - Alan Kemp
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa; (J.T.P.); (P.J.v.V.); (A.K.)
| | - Estelle H. Venter
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa; (R.S.); (E.H.V.)
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia
| |
Collapse
|
7
|
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.
Collapse
|
8
|
Pawęska JT, Jansen van Vuren P, Msimang V, Lô MM, Thiongane Y, Mulumba-Mfumu LK, Mansoor A, Fafetine JM, Magona JW, Boussini H, Bażanow B, Wilson WC, Pepin M, Unger H, Viljoen G. Large-Scale International Validation of an Indirect ELISA Based on Recombinant Nucleocapsid Protein of Rift Valley Fever Virus for the Detection of IgG Antibody in Domestic Ruminants. Viruses 2021; 13:1651. [PMID: 34452515 PMCID: PMC8402881 DOI: 10.3390/v13081651] [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: 07/18/2021] [Revised: 08/06/2021] [Accepted: 08/13/2021] [Indexed: 12/21/2022] Open
Abstract
Diagnostic performance of an indirect enzyme-linked immunosorbent assay (I-ELISA) based on a recombinant nucleocapsid protein (rNP) of the Rift Valley fever virus (RVFV) was validated for the detection of the IgG antibody in sheep (n = 3367), goat (n = 2632), and cattle (n = 3819) sera. Validation data sets were dichotomized according to the results of a virus neutralization test in sera obtained from RVF-endemic (Burkina Faso, Democratic Republic of Congo, Mozambique, Senegal, Uganda, and Yemen) and RVF-free countries (France, Poland, and the USA). Cut-off values were defined using the two-graph receiver operating characteristic analysis. Estimates of the diagnostic specificity of the RVFV rNP I-ELISA in animals from RVF-endemic countries ranged from 98.6% (cattle) to 99.5% (sheep) while in those originating from RVF-free countries, they ranged from 97.7% (sheep) to 98.1% (goats). Estimates of the diagnostic sensitivity in ruminants from RVF-endemic countries ranged from 90.7% (cattle) to 100% (goats). The results of this large-scale international validation study demonstrate the high diagnostic accuracy of the RVFV rNP I-ELISA. Standard incubation and inactivation procedures evaluated did not have an adverse effect on the detectable levels of the anti-RVFV IgG in ruminant sera and thus, together with recombinant antigen-based I-ELISA, provide a simple, safe, and robust diagnostic platform that can be automated and carried out outside expensive bio-containment facilities. These advantages are particularly important for less-resourced countries where there is a need to accelerate and improve RVF surveillance and research on epidemiology as well as to advance disease control measures.
Collapse
Affiliation(s)
- Janusz T. Pawęska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham 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
| | - Petrus Jansen van Vuren
- Australian Centre for Disease Preparedness, CSIRO Health & Biosecurity, Geelong, VIC 3220, Australia;
| | - Veerle Msimang
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham 2131, South Africa;
| | - Modu Moustapha Lô
- Laboratoire National de l’Elevage et de Recherches Vétérinaires, Route de Front de Terre, Dakar Hann 2057, BP, Senegal; (M.M.L.); (Y.T.)
| | - Yaya Thiongane
- Laboratoire National de l’Elevage et de Recherches Vétérinaires, Route de Front de Terre, Dakar Hann 2057, BP, Senegal; (M.M.L.); (Y.T.)
| | - Leopold K. Mulumba-Mfumu
- Ministry of Agriculture, Democratic Republic of Congo, Kinshasa 7948, Democratic Republic of the Congo;
- Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Kinshasa, P.O. Box 127, Kinshasa XI, Democratic Republic of the Congo
| | - Alqadasi Mansoor
- Central Veterinary Laboratory, General Directorate of Animal Health & Veterinary Quarantine, Ministry of Agriculture and Irrigation, Sana’a 31220, Yemen;
- Food and Agriculture Organization Office, Sana’a 31220, Yemen
| | - José M. Fafetine
- Veterinary Faculty, Eduardo Mondlane University, Maputo 1103, Mozambique;
| | - Joseph W. Magona
- National Livestock Resources Research Institute, Tororo P.O. Box 96, Uganda;
- Food and Agriculture Organization, Gaborone P.O. Box 54, Botswana
| | - Hiver Boussini
- Direction Generale Des Services Veterinaires, Ministère des Ressources Animales, Ouagadougou 09 BP 907, Burkina Faso;
- African Union Interafrican Bureau for Animal Resources, Nairobi P.O. Box 30786-00100, Kenya
| | - Barbara Bażanow
- Department of Pathology, Faculty of Veterinary Science, University of Environmental and Life Sciences, 50-375 Wroclaw, Poland;
| | - William C. Wilson
- United States Department of Agriculture, Agricultural Research Service, Foreign Arthropod Borne Animal Diseases Research Unit, National Bio- and Agro-Defense Facility, Manhattan, KS 66502, USA;
| | - Michel Pepin
- Agence Française de Sécurité Sanitaire des Aliments, F-69364 Lyon, France;
- VetAgro Sup, Campus Vétérinaire de Lyon, F-69364 Lyon, France
| | - Hermann Unger
- Joint FAO/IAEA Centre for Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, 1400 Vienna, Austria; (H.U.); (G.V.)
| | - Gerrit Viljoen
- Joint FAO/IAEA Centre for Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, 1400 Vienna, Austria; (H.U.); (G.V.)
| |
Collapse
|
9
|
Preliminary Evaluation of a Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Providing Full Protection against Heterologous Virulent Challenge in Cattle. Vaccines (Basel) 2021; 9:vaccines9070748. [PMID: 34358166 PMCID: PMC8310273 DOI: 10.3390/vaccines9070748] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 01/15/2023] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen that causes periodic outbreaks of abortion in ruminant species and hemorrhagic disease in humans in sub-Saharan Africa. These outbreaks have a significant impact on veterinary and public health. Its introduction to the Arabian Peninsula in 2003 raised concerns of further spread of this transboundary pathogen to non-endemic areas. These concerns are supported by the presence of competent vectors in many non-endemic countries. There is no licensed RVF vaccine available for humans and only a conditionally licensed veterinary vaccine available in the United States. Currently employed modified live attenuated virus vaccines in endemic countries lack the ability for differentiating infected from vaccinated animals (DIVA). Previously, the efficacy of a recombinant subunit vaccine based on the RVFV Gn and Gc glycoproteins, derived from the 1977 human RVFV isolate ZH548, was demonstrated in sheep. In the current study, cattle were vaccinated subcutaneously with the Gn only, or Gn and Gc combined, with either one or two doses of the vaccine and then subjected to heterologous virus challenge with the virulent Kenya-128B-15 RVFV strain, isolated from Aedes mosquitoes in 2006. The elicited immune responses by some vaccine formulations (one or two vaccinations) conferred complete protection from RVF within 35 days after the first vaccination. Vaccines given 35 days prior to RVFV challenge prevented viremia, fever and RVFV-associated histopathological lesions. This study indicates that a recombinant RVFV glycoprotein-based subunit vaccine platform is able to prevent and control RVFV infections in target animals.
Collapse
|
10
|
Petrova V, Kristiansen P, Norheim G, Yimer SA. Rift valley fever: diagnostic challenges and investment needs for vaccine development. BMJ Glob Health 2021; 5:bmjgh-2020-002694. [PMID: 32816810 PMCID: PMC7437696 DOI: 10.1136/bmjgh-2020-002694] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/15/2020] [Accepted: 06/24/2020] [Indexed: 11/04/2022] Open
Abstract
Rift valley fever virus (RVFV) is a causative agent of a viral zoonosis that constitutes a major clinical burden in wild and domestic ruminants. The virus causes major outbreaks in livestock (sheep, goats, cattle and camels) and can be transmitted to humans by contaminated animal products or via arthropod vectors. Human-to-human transmission has not been reported to date, but spill-over events from animals have led to outbreaks in humans in Africa and the Arabian Peninsula. Currently, there is no licensed human vaccine against RVFV and the virus is listed as a priority pathogen by the World Health Organisation (WHO) due to the high epidemic potential and the lack of effective countermeasures. Multiple large RVFV outbreaks have been reported since the virus was discovered. During the last two decades, over 4000 cases and ~1000 deaths have been reported. The lack of systematic surveillance to estimate the true burden and incidence of human RVF disease is a challenge for planning future vaccine efficacy evaluation. This creates a need for robust diagnostic methodologies that can be deployed in remote regions to aid case confirmation, assessment of seroprevalence as well as pathogen surveillance required for the different stages of vaccine evaluation. Here, we perform comprehensive landscaping of the available diagnostic solutions for detection of RVFV in humans. Based on the identified gaps in the currently available in-house and commercially available methods, we highlight the specific investment needs for diagnostics that are critical for accelerating the development of effective vaccines against RVFV.
Collapse
Affiliation(s)
| | - Paul Kristiansen
- Vaccine Research and Development, Coalition for Epidemic Preparedness Innovations, Oslo, Norway
| | | | - Solomon A Yimer
- Vaccine Research and Development, Coalition for Epidemic Preparedness Innovations, Oslo, Norway
| |
Collapse
|
11
|
Bergren NA, Borland EM, Hartman DA, Kading RC. Laboratory demonstration of the vertical transmission of Rift Valley fever virus by Culex tarsalis mosquitoes. PLoS Negl Trop Dis 2021; 15:e0009273. [PMID: 33750981 PMCID: PMC8016277 DOI: 10.1371/journal.pntd.0009273] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 04/01/2021] [Accepted: 02/25/2021] [Indexed: 11/18/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-transmitted virus with proven ability to emerge into naïve geographic areas. Limited field evidence suggests that RVFV is transmitted vertically from parent mosquito to offspring, but until now this mechanism has not been confirmed in the laboratory. Furthermore, this transmission mechanism has allowed for the prediction of RVFV epizootics based on rainfall patterns collected from satellite information. However, in spite of the relevance to the initiation of epizootic events, laboratory confirmation of vertical transmission has remained an elusive research aim for thirty-five years. Herein we present preliminary evidence of the vertical transmission of RVFV by Culex tarsalis mosquitoes after oral exposure to RVFV. Progeny from three successive gonotrophic cycles were reared to adults, with infectious RVFV confirmed in each developmental stage. Virus was detected in ovarian tissues of parental mosquitoes 7 days after imbibing an infectious bloodmeal. Infection was confirmed in progeny as early as the first gonotrophic cycle, with infection rates ranging from 2.0–10.0%. Virus titers among progeny were low, which may indicate a host mechanism suppressing replication. Rift Valley fever virus (RVFV) represents a significant threat in terms of its ability to emerge into naïve geographic areas. Furthermore, RVFV represents a global public health risk due to the ability of many mosquito species to transmit the virus and the ease with which the virus can be transported due to increased globalization. The vertical transmission of RVFV by mosquitoes has long been accepted by the research community due to limited field evidence. However, laboratory confirmation of vertical transmission has remained elusive for thirty-five years. We present the first laboratory evidence of vertical transmission of RVFV in the susceptible North American vector, Culex tarsalis. We present two studies that clearly show 1) the accumulation of RVFV antigen in the ovaries of infected mosquitoes and 2) the transmission of RVFV from parent to offspring immediately following an infectious blood meal.
Collapse
Affiliation(s)
- Nicholas A. Bergren
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado
| | - Erin M. Borland
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado
| | - Daniel A. Hartman
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado
| | - Rebekah C. Kading
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado
- * E-mail:
| |
Collapse
|
12
|
Licciardi S, Loire E, Cardinale E, Gislard M, Dubois E, Cêtre-Sossah C. In vitro shared transcriptomic responses of Aedes aegypti to arboviral infections: example of dengue and Rift Valley fever viruses. Parasit Vectors 2020; 13:395. [PMID: 32758286 PMCID: PMC7404916 DOI: 10.1186/s13071-020-04253-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 07/21/2020] [Indexed: 12/13/2022] Open
Abstract
Background Arthropod borne virus infections are the cause of severe emerging diseases. Among the diseases due to arboviruses, dengue (DEN) and Rift Valley fever (RVF) are in the top ten in the list of diseases responsible of severe human cases worldwide. Understanding the effects of viral infection on gene expression in competent vectors is a challenge for the development of early diagnostic tools and may enable researchers and policy makers to better anticipate outbreaks in the next future. Methods In this study, alterations in gene expression across the entire Aedes aegypti genome during infection with DENV and RVFV were investigated in vitro at two time points of infection, the early phase (24 h) and the late phase (6 days) of infection using the RNA sequencing approach Results A total of 10 upregulated genes that share a similar expression profile during infection with both viruses at early and late phases of infection were identified. Family B and D clip-domain serine proteases (CLIP) were clearly overrepresented as well as C-type lectins and transferrin. Conclusions Our data highlight the presence of 10 viral genes upregulated in Ae. aegypti during infection. They may also be targeted in the case of the development of broad-spectrum anti-viral diagnostic tools focusing the mosquito vectors rather than the mammalian hosts as they may predict the emergence of outbreaks.![]()
Collapse
Affiliation(s)
- Séverine Licciardi
- CIRAD, UMR ASTRE, 97490, Sainte Clotilde, La Réunion, France.,ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France
| | - Etienne Loire
- ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France.,CIRAD, UMR ASTRE, 34395, Montpellier, France
| | - Eric Cardinale
- CIRAD, UMR ASTRE, 97490, Sainte Clotilde, La Réunion, France.,ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France
| | - Marie Gislard
- MGX-Montpellier Genomix, IGF, INSERM, CNRS, University of Montpellier, Montpellier, France
| | - Emeric Dubois
- MGX-Montpellier Genomix, IGF, INSERM, CNRS, University of Montpellier, Montpellier, France
| | - Catherine Cêtre-Sossah
- CIRAD, UMR ASTRE, 97490, Sainte Clotilde, La Réunion, France. .,ASTRE, University of Montpellier, CIRAD, INRAe, Montpellier, France.
| |
Collapse
|
13
|
Kroeker AL, Babiuk S, Pickering BS, Richt JA, Wilson WC. Livestock Challenge Models of Rift Valley Fever for Agricultural Vaccine Testing. Front Vet Sci 2020; 7:238. [PMID: 32528981 PMCID: PMC7266933 DOI: 10.3389/fvets.2020.00238] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 04/07/2020] [Indexed: 11/13/2022] Open
Abstract
Since the discovery of Rift Valley Fever virus (RVFV) in Kenya in 1930, the virus has become widespread throughout most of Africa and is characterized by sporadic outbreaks. A mosquito-borne pathogen, RVFV is poised to move beyond the African continent and the Middle East and emerge in Europe and Asia. There is a risk that RVFV could also appear in the Americas, similar to the West Nile virus. In light of this potential threat, multiple studies have been undertaken to establish international surveillance programs and diagnostic tools, develop models of transmission dynamics and risk factors for infection, and to develop a variety of vaccines as countermeasures. Furthermore, considerable efforts to establish reliable challenge models of Rift Valley fever virus have been made and platforms for testing potential vaccines and therapeutics in target species have been established. This review emphasizes the progress and insights from a North American perspective to establish challenge models in target livestock such as cattle, sheep, and goats in comparisons to other researchers' reports. A brief summary of the potential role of wildlife, such as buffalo and white-tailed deer as reservoir species will also be discussed.
Collapse
Affiliation(s)
- Andrea Louise Kroeker
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada
| | - Shawn Babiuk
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - Bradley S Pickering
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada.,Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada
| | - Juergen A Richt
- Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), Manhattan, KS, United States
| | - William C Wilson
- USDA, Arthropod-Borne Animal Diseases Research Unit (ABADRU), Manhattan, KS, United States
| |
Collapse
|
14
|
Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Depner K, Drewe JA, Garin-Bastuji B, Rojas JLG, Schmidt CG, Michel V, Chueca MÁM, Roberts HC, Sihvonen LH, Stahl K, Calvo AV, Viltrop A, Winckler C, Bett B, Cetre-Sossah C, Chevalier V, Devos C, Gubbins S, Monaco F, Sotiria-Eleni A, Broglia A, Abrahantes JC, Dhollander S, Stede YVD, Zancanaro G. Rift Valley Fever - epidemiological update and risk of introduction into Europe. EFSA J 2020; 18:e06041. [PMID: 33020705 PMCID: PMC7527653 DOI: 10.2903/j.efsa.2020.6041] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Rift Valley fever (RVF) is a vector-borne disease transmitted by a broad spectrum of mosquito species, especially Aedes and Culex genus, to animals (domestic and wild ruminants and camels) and humans. Rift Valley fever is endemic in sub-Saharan Africa and in the Arabian Peninsula, with periodic epidemics characterised by 5-15 years of inter-epizootic periods. In the last two decades, RVF was notified in new African regions (e.g. Sahel), RVF epidemics occurred more frequently and low-level enzootic virus circulation has been demonstrated in livestock in various areas. Recent outbreaks in a French overseas department and some seropositive cases detected in Turkey, Tunisia and Libya raised the attention of the EU for a possible incursion into neighbouring countries. The movement of live animals is the most important pathway for RVF spread from the African endemic areas to North Africa and the Middle East. The movement of infected animals and infected vectors when shipped by flights, containers or road transport is considered as other plausible pathways of introduction into Europe. The overall risk of introduction of RVF into EU through the movement of infected animals is very low in all the EU regions and in all MSs (less than one epidemic every 500 years), given the strict EU animal import policy. The same level of risk of introduction in all the EU regions was estimated also considering the movement of infected vectors, with the highest level for Belgium, Greece, Malta, the Netherlands (one epidemic every 228-700 years), mainly linked to the number of connections by air and sea transports with African RVF infected countries. Although the EU territory does not seem to be directly exposed to an imminent risk of RVFV introduction, the risk of further spread into countries neighbouring the EU and the risks of possible introduction of infected vectors, suggest that EU authorities need to strengthen their surveillance and response capacities, as well as the collaboration with North African and Middle Eastern countries.
Collapse
|
15
|
Kading RC, Abworo EO, Hamer GL. Rift Valley Fever Virus, Japanese Encephalitis Virus, and African Swine Fever Virus: Three Transboundary, Vector-Borne, Veterinary Biothreats With Diverse Surveillance, and Response Capacity Needs. Front Vet Sci 2019; 6:458. [PMID: 31921916 PMCID: PMC6923192 DOI: 10.3389/fvets.2019.00458] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/28/2019] [Indexed: 12/20/2022] Open
Abstract
Early detection of emerging foreign animal diseases is critical to pathogen surveillance and control programs. Rift valley fever virus (RVFV), Japanese encephalitis virus (JEV), and African swine fever virus (ASFV) represent three taxonomically and ecologically diverse vector-borne viruses with the potential to be introduced to the United States. To promote preparedness for such an event, we reviewed the current surveillance strategies and diagnostic tools in practice around the world for these emerging viruses, and summarized key points pertaining to the availability of existing guidelines and strategic approaches for early detection, surveillance, and disease management activities. We compare and contrast the surveillance and management approaches of these three diverse agents of disease as case studies to emphasize the importance of the ecological context and biology of vectors and vertebrate hosts. The information presented in this review will inform stakeholders of the current state of surveillance approaches against these transboundary foreign animal disease which threaten the United States.
Collapse
Affiliation(s)
- Rebekah C Kading
- Arthropod-Borne Infectious Disease Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | | | - Gabriel L Hamer
- Department of Entomology, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, United States
| |
Collapse
|
16
|
Cêtre-Sossah C, Pédarrieu A, Juremalm M, Jansen Van Vuren P, Brun A, Ould EL Mamy AB, Héraud JM, Filippone C, Ravalohery JP, Chaabihi H, Albina E, Dommergues L, Paweska J, Cardinale E. Development and validation of a pen side test for Rift Valley fever. PLoS Negl Trop Dis 2019; 13:e0007700. [PMID: 31509527 PMCID: PMC6738586 DOI: 10.1371/journal.pntd.0007700] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 07/23/2019] [Indexed: 01/25/2023] Open
Abstract
Background Rift Valley fever (RVF) is one of the main vector borne zoonotic diseases that affects a wide range of ruminants and human beings in Africa and the Arabian Peninsula. A rapid and specific test for RVF diagnosis at the site of a suspected outbreak is crucial for the implementation of control measures. Methodology/Principal findings A first-line lateral flow immunochromatographic strip test (LFT) was developed for the detection of the nucleoprotein (N) of the RVF virus (RVFV). Its diagnostic performance characteristics were evaluated using reference stocks isolates recovered from different hosts and in geographic regions mimicking clinical specimens and from known RVF negative serum samples. A high level of diagnostic accuracy (DSe (35/35), DSp (167/169)) was observed, including the absence of cross-reactivity with viruses belonging to different genera. Conclusion/Significance The fact no specialized reagents and laboratory equipment are needed, make this assay a valuable, first-line diagnostic tool in resource-poor diagnostic territories for on-site RVFV detection, however the staff require training. Rift Valley fever (RVF) is a viral disease that affects a wide range of animals and human beings in Africa and the Arabian Peninsula involving low case fatality rates. A rapid and specific test for RVF diagnosis at the site of a suspected outbreak is crucial for the implementation of control measures. Here, we report the development and the evaluation of the diagnostic performance characteristics of a pen-side test found to be a highly accurate and valuable first-line diagnostic tool for on-site RVF detection.
Collapse
Affiliation(s)
- Catherine Cêtre-Sossah
- ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR ASTRE, Sainte‐Clotilde, La Réunion, France
- * E-mail:
| | | | | | - Petrus Jansen Van Vuren
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Sandringham-Johannesburg, South Africa
| | | | | | | | - Claudia Filippone
- Virology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | | | | | - Emmanuel Albina
- ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR ASTRE, Petit Bourg, Guadeloupe, France
| | | | - Janusz Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Sandringham-Johannesburg, South Africa
| | - Eric Cardinale
- ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
- CIRAD, UMR ASTRE, Sainte‐Clotilde, La Réunion, France
| |
Collapse
|
17
|
A strand-specific real-time quantitative RT-PCR assay for distinguishing the genomic and antigenomic RNAs of Rift Valley fever phlebovirus. J Virol Methods 2019; 272:113701. [PMID: 31315022 DOI: 10.1016/j.jviromet.2019.113701] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/13/2019] [Indexed: 11/21/2022]
Abstract
Rift Valley Fever phlebovirus (RVFV), genus Phlebovirus, family Phenuiviridae, order Bunyavirales, has a single-stranded, negative-sense RNA genome, consisting of L, M and S segments. Here, we report the establishment of a strand-specific, quantitative reverse transcription (RT)-PCR assay system that can selectively distinguish between the genomic and antigenomic RNAs of each of the three viral RNA segments produced in RVFV-infected cells. To circumvent the obstacle of primer-independent cDNA synthesis during RT, we used a tagged, strand-specific RT primer, carrying a non-viral 'tag' sequence at the 5' end, which ensured the strand-specificity through the selective amplification of only the tagged cDNA in the real-time PCR assay. We used this assay system to examine the kinetics of intracellular accumulation of genomic and antigenomic viral RNAs in mammalian cells infected with the MP-12 strain of RVFV. The genomic RNA copy numbers, for all three viral RNA segments, were higher than that of their corresponding antigenomic RNAs throughout the time-course of infection, with a notable exception, wherein the M segment genomic and antigenomic RNAs exhibited similar copy numbers at specific times post-infection. Overall, this assay system could be a useful tool to gain an insight into the mechanisms of RNA replication and packaging in RVFV.
Collapse
|
18
|
Wilson WC, Kim IJ, Trujillo JD, Sunwoo SY, Noronha LE, Urbaniak K, McVey DS, Drolet BS, Morozov I, Faburay B, Schirtzinger EE, Koopman T, Indran SV, Balaraman V, Richt JA. Susceptibility of White-Tailed Deer to Rift Valley Fever Virus. Emerg Infect Dis 2019; 24:1717-1719. [PMID: 30124402 PMCID: PMC6106403 DOI: 10.3201/eid2409.180265] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Rift Valley fever virus, a zoonotic arbovirus, poses major health threats to livestock and humans if introduced into the United States. White-tailed deer, which are abundant throughout the country, might be sentinel animals for arboviruses. We determined the susceptibility of these deer to this virus and provide evidence for a potentially major epidemiologic role.
Collapse
|
19
|
Ragan IK, Schuck KN, Upreti D, Odendaal L, Richt JA, Trujillo JD, Wilson WC, Davis AS. Rift Valley Fever Viral RNA Detection by In Situ Hybridization in Formalin-Fixed, Paraffin-Embedded Tissues. Vector Borne Zoonotic Dis 2019; 19:553-556. [PMID: 30720389 DOI: 10.1089/vbz.2018.2383] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sporadic outbreaks of Rift Valley fever virus (RVFV), a zoonotic, mosquito-borne Phlebovirus, cause abortion storms and death in sheep and cattle resulting in catastrophic economic impacts in endemic regions of Africa. More recently, with changes in competent vector distribution, growing international trade, and its potential use for bioterrorism, RVFV has become a transboundary animal disease of significant concern. New and sensitive techniques that determine RVFV presence, while lessening the potential for environmental contamination and human risk, through the use of inactivated, noninfectious samples such as formalin-fixed, paraffin-embedded (FFPE) tissues are needed. FFPE tissue in situ hybridization (ISH) enables the detection of nucleic acid sequences within the visual context of cellular and tissue morphology. Here, we present a chromogenic pan-RVFV ISH assay based on RNAscope® technology, which is able to detect multiple RVFV strains in FFPE tissues, enabling visual correlation of RVFV RNA presence with histopathologic lesions.
Collapse
Affiliation(s)
- Izabela K Ragan
- 1 Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | - Kaitlynn N Schuck
- 1 Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | - Deepa Upreti
- 1 Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | - Lieza Odendaal
- 2 Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria, South Africa
| | - Juergen A Richt
- 1 Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | - Jessie D Trujillo
- 1 Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | - William C Wilson
- 3 USDA-ARS Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Manhattan, Kansas
| | - A Sally Davis
- 1 Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas.,2 Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Pretoria, South Africa
| |
Collapse
|
20
|
Kim HJ, Lyoo HR, Choi JS, Lee YH, Kim BH, Yoo HS. Development of a Quantitative RT-PCR Assay to Differentiate Rift Valley Fever Virus Smithburn Vaccine Strain from Clone 13 Vaccine Strain. Vector Borne Zoonotic Dis 2018; 19:121-127. [PMID: 30300113 DOI: 10.1089/vbz.2018.2342] [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
A new quantitative RT-PCR assay was developed to differentiate Rift Valley fever (RVF) Smithburn vaccine strain from Clone 13 vaccine strain. The new qRT-PCR assay targeting the S segment (NSs and N gene) was tested on synthesized standard RNA and MP-12 strain viruses. The detection limit of the new qRT-PCR assay is 1 copy/μL of NSs and N, and is able to differentiate the Smithburn vaccine strain of RVF from the Clone 13 vaccine strain. No cross-reactivity with other vector-borne viruses was observed, a factor that is especially important in the Republic of Korea (ROK). To examine the performance of the qRT-PCR, intra- and inter-assay variability data were analyzed and showed high reproducibility. These results indicate that the new qRT-PCR can be used as a safe and cost-effective test. Furthermore, this result suggests the possibility of differentiation between infected and vaccinated animals diagnostic test in RVF-free countries including ROK.
Collapse
Affiliation(s)
- Hyun-Joo Kim
- 1 Foreign Animal Disease Division, Animal and Plant Quarantine Agency , Gimcheon-si, Republic of Korea.,2 Department of Infectious Diseases, Colleges of Veterinary Medicine, Seoul National University , Seoul, Republic of Korea
| | - Hye-Rhyoung Lyoo
- 3 Department of Infectious Diseases and Immunology, Virology Division, Faculty of Veterinary Medicine, Utrecht University , Utrecht, the Netherlands
| | - Jeong-Soo Choi
- 1 Foreign Animal Disease Division, Animal and Plant Quarantine Agency , Gimcheon-si, Republic of Korea
| | - Yoon-Hee Lee
- 1 Foreign Animal Disease Division, Animal and Plant Quarantine Agency , Gimcheon-si, Republic of Korea
| | - Byoung-Han Kim
- 1 Foreign Animal Disease Division, Animal and Plant Quarantine Agency , Gimcheon-si, Republic of Korea
| | - Han Sang Yoo
- 2 Department of Infectious Diseases, Colleges of Veterinary Medicine, Seoul National University , Seoul, Republic of Korea
| |
Collapse
|
21
|
Clark MHA, Warimwe GM, Di Nardo A, Lyons NA, Gubbins S. Systematic literature review of Rift Valley fever virus seroprevalence in livestock, wildlife and humans in Africa from 1968 to 2016. PLoS Negl Trop Dis 2018; 12:e0006627. [PMID: 30036382 PMCID: PMC6072204 DOI: 10.1371/journal.pntd.0006627] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 08/02/2018] [Accepted: 06/22/2018] [Indexed: 02/03/2023] Open
Abstract
Background Rift Valley fever virus (RVFV) is a zoonotic arbovirus that causes severe disease in livestock and humans. The virus has caused recurrent outbreaks in Africa and the Arabian Peninsula since its discovery in 1931. This review sought to evaluate RVFV seroprevalence across the African continent in livestock, wildlife and humans in order to understand the spatio-temporal distribution of RVFV seroprevalence and to identify knowledge gaps and areas requiring further research. Risk factors associated with seropositivity were identified and study designs evaluated to understand the validity of their results. Methodology The Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to produce a protocol to systematically search for RVFV seroprevalence studies in PubMed and Web of Science databases. The Strengthening the Reporting of Observational studies in Epidemiology (STROBE) statement guided the evaluation of study design and analyses. Principal findings A total of 174 RVFV seroprevalence studies in 126 articles fulfilled the inclusion criteria. RVFV seroprevalence was recorded in 31 African countries from 1968 to 2016 and varied by time, species and country. RVFV seroprevalence articles including either livestock and humans or livestock and wildlife seroprevalence records were limited in number (8/126). No articles considered wildlife, livestock and human seroprevalence concurrently, nor wildlife and humans alone. Many studies did not account for study design bias or the sensitivity and specificity of diagnostic tests. Conclusions Future research should focus on conducting seroprevalence studies at the wildlife, livestock and human interface to better understand the nature of cross-species transmission of RVFV. Reporting should be more transparent and biases accounted for in future seroprevalence research to understand the true burden of disease on the African continent. Rift Valley fever virus (RVFV) is a vector-borne virus that infects wildlife and livestock, and can subsequently spread to humans. Due to the nature of the disease it has the potential to cause substantial economic and public health impacts. Rift Valley Fever (RVF) has been identified in Africa and the Arabian Peninsula, but has the potential to spread more widely. This systematic review assessed the distribution of RVF in livestock and humans in Africa by collating all the relevant studies we could find, extracting the data and critically evaluating them. Understanding when and where RVF has occurred in Africa and why some animals and humans get disease helps target control strategies and, in particular, those that reduce spread from livestock to humans. Furthermore, by evaluating past studies we can ensure that future ones are more robust and reproducible, so they can help us better understand the disease.
Collapse
Affiliation(s)
- Madeleine H. A. Clark
- Transmission Biology Group, The Pirbright Institute, Pirbright, Woking, United Kingdom
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - George M. Warimwe
- Biosciences Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Antonello Di Nardo
- Vesicular Disease Reference Laboratories, The Pirbright Institute, Pirbright, Woking, United Kingdom
| | - Nicholas A. Lyons
- Vesicular Disease Reference Laboratories, The Pirbright Institute, Pirbright, Woking, United Kingdom
| | - Simon Gubbins
- Transmission Biology Group, The Pirbright Institute, Pirbright, Woking, United Kingdom
| |
Collapse
|
22
|
Montoya-Ruiz C, Rodas JD. Epidemiological Surveillance of Viral Hemorrhagic Fevers With Emphasis on Clinical Virology. Methods Mol Biol 2018; 1604:55-78. [PMID: 28986825 DOI: 10.1007/978-1-4939-6981-4_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
This article will outline surveillance approaches for viral hemorrhagic fevers. Specific methods for surveillance of clinical samples will be emphasized. Separate articles will describe methods for surveillance of rodent-borne viruses (roboviruses) and arthropod-borne viruses (arboviruses). Since the appearance of hantaviruses and arenaviruses in the Americas, more than 30 different species in each group have been established, and therefore they have become the most frequently emerging viruses. Flaviviruses such as yellow fever and dengue viruses, although easier to recognize, are also more widely spread and therefore considered a very important public health issue, particularly for under-developed countries. On the other hand, marburgviruses and ebolaviruses, previously thought to be restricted to the African continent, have recently been shown to be more global. For many of these agents virus isolation has been a challenging task: trapping the specific vectors (mosquitoes and ticks), and reservoirs (rodents and bats), or obtaining the samples from suspected clinical human cases demands special protective gear, uncommon devices (respirators), special facilities (BSL-3 and 4), and particular skills to recognize the slow and inapparent cytopathic effects in cell culture. Alternatively, serological and molecular approaches have been very helpful in discovering and describing newly emerging viruses in many areas where the previous resources are unavailable. Unfortunately, in many cases, detailed studies have been performed only after outbreaks occur, and then active surveillance is needed to prevent viral dissemination in human populations.
Collapse
Affiliation(s)
- Carolina Montoya-Ruiz
- Linea de Zoonosis Emergentes y Re-emergentes, Grupo Centauro, Facultad de Ciencias Agrarias, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia
| | - Juan David Rodas
- Linea de Zoonosis Emergentes y Re-emergentes, Grupo Centauro, Facultad de Ciencias Agrarias, Universidad de Antioquia, Calle 70 No. 52-21, Medellín, Colombia.
| |
Collapse
|
23
|
Métras R, Dommergues L, Ortiz K, Pannequin M, Schuler C, Roux P, Edmunds JW, Keeling MJ, Cêtre-Sossah C, Cardinale E. Absence of Evidence of Rift Valley Fever Infection in Eulemur fulvus (Brown Lemur) in Mayotte During an Interepidemic Period. Vector Borne Zoonotic Dis 2017; 17:358-360. [PMID: 28437185 PMCID: PMC5421605 DOI: 10.1089/vbz.2016.2079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The potential role of Eulemur fulvus (brown lemur) in the epidemiology of Rift Valley fever (RVF) in Mayotte, during an interepidemic period, was explored. In February and March 2016, 72 animals were blood sampled and tested for RVF. No evidence of RVF genome or antibodies was found in the samples. The role of other wild mammals on the island should, however, be further investigated.
Collapse
Affiliation(s)
- Raphaëlle Métras
- 1 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , London, United Kingdom
| | - Laure Dommergues
- 2 GDS Mayotte-Coopérative Agricole des Eleveurs Mahorais, Coconi, Mayotte, France
| | - Katia Ortiz
- 3 Museum National d'Histoire Naturelle UMR 7205, Institut de Systématique , Evolution, Biodiversité, ISYEB, Réserve Zoologique de la Haute-Touche, Obterre, France
| | - Marion Pannequin
- 2 GDS Mayotte-Coopérative Agricole des Eleveurs Mahorais, Coconi, Mayotte, France
| | | | - Patrick Roux
- 3 Museum National d'Histoire Naturelle UMR 7205, Institut de Systématique , Evolution, Biodiversité, ISYEB, Réserve Zoologique de la Haute-Touche, Obterre, France
| | - John W Edmunds
- 1 Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine , London, United Kingdom
| | - Matt J Keeling
- 5 Warwick Infectious Disease Epidemiology Research, Warwick University , Coventry, United Kingdom
| | - Catherine Cêtre-Sossah
- 6 UMR CMAEE, CIRAD, Sainte-Clotilde, La Réunion, France .,7 UMR1309 CMAEE, INRA, Montpellier, France
| | - Eric Cardinale
- 6 UMR CMAEE, CIRAD, Sainte-Clotilde, La Réunion, France .,7 UMR1309 CMAEE, INRA, Montpellier, France
| |
Collapse
|
24
|
Lang Y, Henningson J, Jasperson D, Li Y, Lee J, Ma J, Li Y, Cao N, Liu H, Wilson W, Richt J, Ruder M, McVey S, Ma W. Mouse model for the Rift Valley fever virus MP12 strain infection. Vet Microbiol 2016; 195:70-77. [PMID: 27771072 DOI: 10.1016/j.vetmic.2016.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 08/25/2016] [Accepted: 09/20/2016] [Indexed: 01/08/2023]
Abstract
Rift Valley fever virus (RVFV), a Category A pathogen and select agent, is the causative agent of Rift Valley fever. To date, no fully licensed vaccine is available in the U.S. for human or animal use and effective antiviral drugs have not been identified. The RVFV MP12 strain is conditionally licensed for use for veterinary purposes in the U.S. which was excluded from the select agent rule of Health and Human Services and the U.S. Department of Agriculture. The MP12 vaccine strain is commonly used in BSL-2 laboratories that is generally not virulent in mice. To establish a small animal model that can be used in a BSL-2 facility for antiviral drug development, we investigated susceptibility of six mouse strains (129S6/SvEv, STAT-1 KO, 129S1/SvlmJ, C57BL/6J, NZW/LacJ, BALB/c) to the MP12 virus infection via an intranasal inoculation route. Severe weight loss, obvious clinical and neurologic signs, and 50% mortality was observed in the STAT-1 KO mice, whereas the other 5 mouse strains did not display obvious and/or severe disease. Virus replication and histopathological lesions were detected in brain and liver of MP12-infected STAT-1 KO mice that developed the acute-onset hepatitis and delayed-onset encephalitis. In conclusion, the STAT-1 KO mouse strain is susceptible to MP12 virus infection, indicating that it can be used to investigate RVFV antivirals in a BSL-2 environment.
Collapse
Affiliation(s)
- Yuekun Lang
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Jamie Henningson
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Dane Jasperson
- USDA, ARS, Arthropod-Borne Animal Diseases Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS, USA
| | - Yonghai Li
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Jinhwa Lee
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Jingjiao Ma
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Yuhao Li
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Nan Cao
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Haixia Liu
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - William Wilson
- USDA, ARS, Arthropod-Borne Animal Diseases Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS, USA
| | - Juergen Richt
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA
| | - Mark Ruder
- USDA, ARS, Arthropod-Borne Animal Diseases Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS, USA
| | - Scott McVey
- USDA, ARS, Arthropod-Borne Animal Diseases Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS, USA
| | - Wenjun Ma
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, KS, USA.
| |
Collapse
|
25
|
Safety and Efficacy Profile of Commercial Veterinary Vaccines against Rift Valley Fever: A Review Study. J Immunol Res 2016; 2016:7346294. [PMID: 27689098 PMCID: PMC5027037 DOI: 10.1155/2016/7346294] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/13/2016] [Accepted: 06/06/2016] [Indexed: 11/25/2022] Open
Abstract
Rift Valley Fever (RVF) is an infectious illness with serious clinical manifestations and health consequences in humans as well as a wide range of domestic ruminants. This review provides significant information about the prevention options of RVF along with the safety-efficacy profile of commercial vaccines and some of RVF vaccination strategies. Information presented in this paper was obtained through a systematic investigation of published data about RVF vaccines. Like other viral diseases, the prevention of RVF relies heavily on immunization of susceptible herds with safe and cost-effective vaccine that is able to confer long-term protective immunity. Several strains of RVF vaccines have been developed and are available in commercial production including Formalin-Inactivated vaccine, live attenuated Smithburn vaccine, and the most recent Clone13. Although Formalin-Inactivated vaccine and live attenuated Smithburn vaccine are immunogenic and widely used in prevention programs, they proved to be accompanied by significant concerns. Despite Clone13 vaccine being suggested as safe in pregnant ewes and as highly immunogenic along with its potential for differentiating infected from vaccinated animals (DIVA), a recent study raised concerns about the safety of the vaccine during the first trimester of gestation. Accordingly, RVF vaccines that are currently available in the market to a significant extent do not fulfill the requirements of safety, potency, and DIVA. These adverse effects stressed the need for developing new vaccines with an excellent safety profile to bridge the gap in safety and immunity. Bringing RVF vaccine candidates to local markets besides the absence of validated serological test for DIVA remain the major challenges of RVF control.
Collapse
|
26
|
Wilson WC, Davis AS, Gaudreault NN, Faburay B, Trujillo JD, Shivanna V, Sunwoo SY, Balogh A, Endalew A, Ma W, Drolet BS, Ruder MG, Morozov I, McVey DS, Richt JA. Experimental Infection of Calves by Two Genetically-Distinct Strains of Rift Valley Fever Virus. Viruses 2016; 8:v8050145. [PMID: 27223298 PMCID: PMC4885100 DOI: 10.3390/v8050145] [Citation(s) in RCA: 27] [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: 04/01/2016] [Revised: 05/07/2016] [Accepted: 05/12/2016] [Indexed: 12/13/2022] Open
Abstract
Recent outbreaks of Rift Valley fever in ruminant livestock, characterized by mass abortion and high mortality rates in neonates, have raised international interest in improving vaccine control strategies. Previously, we developed a reliable challenge model for sheep that improves the evaluation of existing and novel vaccines in sheep. This sheep model demonstrated differences in the pathogenesis of Rift Valley fever virus (RVFV) infection between two genetically-distinct wild-type strains of the virus, Saudi Arabia 2001 (SA01) and Kenya 2006 (Ken06). Here, we evaluated the pathogenicity of these two RVFV strains in mixed breed beef calves. There was a transient increase in rectal temperatures with both virus strains, but this clinical sign was less consistent than previously reported with sheep. Three of the five Ken06-infected animals had an early-onset viremia, one day post-infection (dpi), with viremia lasting at least three days. The same number of SA01-infected animals developed viremia at 2 dpi, but it only persisted through 3 dpi in one animal. The average virus titer for the SA01-infected calves was 1.6 logs less than for the Ken06-infected calves. Calves, inoculated with either strain, seroconverted by 5 dpi and showed time-dependent increases in their virus-neutralizing antibody titers. Consistent with the results obtained in the previous sheep study, elevated liver enzyme levels, more severe liver pathology and higher virus titers occurred with the Ken06 strain as compared to the SA01 strain. These results demonstrate the establishment of a virulent challenge model for vaccine evaluation in calves.
Collapse
Affiliation(s)
- William C Wilson
- United States Department of Agriculture, Agricultural Research Service, Arthropod Borne Animal Disease Research Unit, 1515 College Ave., Manhattan, KS 66502, USA.
| | - A Sally Davis
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Natasha N Gaudreault
- United States Department of Agriculture, Agricultural Research Service, Arthropod Borne Animal Disease Research Unit, 1515 College Ave., Manhattan, KS 66502, USA.
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Bonto Faburay
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Jessie D Trujillo
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Vinay Shivanna
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Sun Young Sunwoo
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Aaron Balogh
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Abaineh Endalew
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Wenjun Ma
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - Barbara S Drolet
- United States Department of Agriculture, Agricultural Research Service, Arthropod Borne Animal Disease Research Unit, 1515 College Ave., Manhattan, KS 66502, USA.
| | - Mark G Ruder
- United States Department of Agriculture, Agricultural Research Service, Arthropod Borne Animal Disease Research Unit, 1515 College Ave., Manhattan, KS 66502, USA.
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
| | - Igor Morozov
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| | - D Scott McVey
- United States Department of Agriculture, Agricultural Research Service, Arthropod Borne Animal Disease Research Unit, 1515 College Ave., Manhattan, KS 66502, USA.
| | - Juergen A Richt
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
| |
Collapse
|
27
|
Kim HJ, Lyoo HR, Park JY, Choi JS, Lee JY, Jeoung HY, Cho YS, Cho IS, Yoo HS. Surveillance of Rift Valley Fever Virus in Mosquito Vectors of the Republic of Korea. Vector Borne Zoonotic Dis 2016; 16:131-5. [DOI: 10.1089/vbz.2015.1843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Hyun-Joo Kim
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - Hye-Rhyoung Lyoo
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - Jee-Yong Park
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - Jeong-Soo Choi
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - Ji-Youn Lee
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - Hye-Young Jeoung
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - Yun-Sang Cho
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - In-Soo Cho
- Foreign Animal Disease Division, Animal and Plant Quarantine Agency, Anyang, Republic of Korea
| | - Han Sang Yoo
- College of Veterinary Medicine and BK21 PLUS, Seoul National University, Seoul, Republic of Korea
- Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, Republic of Korea
| |
Collapse
|
28
|
Development of a sheep challenge model for Rift Valley fever. Virology 2015; 489:128-40. [PMID: 26748334 DOI: 10.1016/j.virol.2015.12.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/03/2015] [Accepted: 12/08/2015] [Indexed: 11/20/2022]
Abstract
Rift Valley fever (RVF) is a zoonotic disease that causes severe epizootics in ruminants, characterized by mass abortion and high mortality rates in younger animals. The development of a reliable challenge model is an important prerequisite for evaluation of existing and novel vaccines. A study aimed at comparing the pathogenesis of RVF virus infection in US sheep using two genetically different wild type strains of the virus (SA01-1322 and Kenya-128B-15) was performed. A group of sheep was inoculated with both strains and all infected sheep manifested early-onset viremia accompanied by a transient increase in temperatures. The Kenya-128B-15 strain manifested higher virulence compared to SA01-1322 by inducing more severe liver damage, and longer and higher viremia. Genome sequence analysis revealed sequence variations between the two isolates, which potentially could account for the observed phenotypic differences. We conclude that Kenya-128B-15 sheep infection represents a good and virulent challenge model for RVF.
Collapse
|
29
|
Gaudreault NN, Indran SV, Bryant PK, Richt JA, Wilson WC. Comparison of Rift Valley fever virus replication in North American livestock and wildlife cell lines. Front Microbiol 2015; 6:664. [PMID: 26175725 PMCID: PMC4485352 DOI: 10.3389/fmicb.2015.00664] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/17/2015] [Indexed: 01/26/2023] Open
Abstract
Rift Valley fever virus (RVFV) causes disease outbreaks across Africa and the Arabian Peninsula, resulting in high morbidity and mortality among young domestic livestock, frequent abortions in pregnant animals, and potentially severe or fatal disease in humans. The possibility of RVFV spreading to the United States or other countries worldwide is of significant concern to animal and public health, livestock production, and trade. The mechanism for persistence of RVFV during inter-epidemic periods may be through mosquito transovarial transmission and/or by means of a wildlife reservoir. Field investigations in endemic areas and previous in vivo studies have demonstrated that RVFV can infect a wide range of animals, including indigenous wild ruminants of Africa. Yet no predominant wildlife reservoir has been identified, and gaps in our knowledge of RVFV permissive hosts still remain. In North America, domestic goats, sheep, and cattle are susceptible hosts for RVFV and several competent vectors exist. Wild ruminants such as deer might serve as a virus reservoir and given their abundance, wide distribution, and overlap with livestock farms and human populated areas could represent an important risk factor. The objective of this study was to assess a variety of cell lines derived from North American livestock and wildlife for susceptibility and permissiveness to RVFV. Results of this study suggest that RVFV could potentially replicate in native deer species such as white-tailed deer, and possibly a wide range of non-ruminant animals. This work serves to guide and support future animal model studies and risk model assessment regarding this high-consequence zoonotic pathogen.
Collapse
Affiliation(s)
- Natasha N Gaudreault
- Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Agricultural Research Service, United States Department of Agriculture Manhattan, KS, USA
| | - Sabarish V Indran
- Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University Manhattan, KS, USA
| | - P K Bryant
- Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Agricultural Research Service, United States Department of Agriculture Manhattan, KS, USA
| | - Juergen A Richt
- Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University Manhattan, KS, USA
| | - William C Wilson
- Arthropod-Borne Animal Diseases Research Unit, Center for Grain and Animal Health Research, Agricultural Research Service, United States Department of Agriculture Manhattan, KS, USA
| |
Collapse
|
30
|
Evaluation of the Efficacy, Potential for Vector Transmission, and Duration of Immunity of MP-12, an Attenuated Rift Valley Fever Virus Vaccine Candidate, in Sheep. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:930-7. [PMID: 26041042 DOI: 10.1128/cvi.00114-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/30/2015] [Indexed: 11/20/2022]
Abstract
Rift Valley fever virus (RVFV) causes serious disease in ruminants and humans in Africa. In North America, there are susceptible ruminant hosts and competent mosquito vectors, yet there are no fully licensed animal vaccines for this arthropod-borne virus, should it be introduced. Studies in sheep and cattle have found the attenuated strain of RVFV, MP-12, to be both safe and efficacious based on early testing, and a 2-year conditional license for use in U.S. livestock has been issued. The purpose of this study was to further determine the vaccine's potential to infect mosquitoes, the duration of humoral immunity to 24 months postvaccination, and the ability to prevent disease and viremia from a virulent challenge. Vaccination experiments conducted in sheep found no evidence of a potential for vector transmission to 4 North American mosquito species. Neutralizing antibodies were elicited, with titers of >1:40 still present at 24 months postvaccination. Vaccinates were protected from clinical signs and detectable viremia after challenge with virulent virus, while control sheep had fever and high-titered viremia extending for 5 days. Antibodies to three viral proteins (nucleocapsid N, the N-terminal half of glycoprotein GN, and the nonstructural protein from the short segment NSs) were also detected to 24 months using competitive enzyme-linked immunosorbent assays. This study demonstrates that the MP-12 vaccine given as a single dose in sheep generates protective immunity to a virulent challenge with antibody duration of at least 2 years, with no evidence of a risk for vector transmission.
Collapse
|
31
|
Wilson WC, Bawa B, Drolet BS, Lehiy C, Faburay B, Jasperson DC, Reister L, Gaudreault NN, Carlson J, Ma W, Morozov I, McVey DS, Richt JA. Evaluation of lamb and calf responses to Rift Valley fever MP-12 vaccination. Vet Microbiol 2014; 172:44-50. [PMID: 24856133 DOI: 10.1016/j.vetmic.2014.04.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/03/2014] [Accepted: 04/08/2014] [Indexed: 11/30/2022]
Abstract
Rift Valley fever (RVF) is an important viral disease of animals and humans in Africa and the Middle East that is transmitted by mosquitoes. The disease is of concern to international agricultural and public health communities. The RVFV MP-12 strain has been the most safety tested attenuated vaccine strain; thus it is being considered as a potential vaccine for the US national veterinary stockpile. This study was designed to establish safety protocols for large animal research with virulent RVF viruses, establish a target host immune response baseline using RVF MP-12 strain, and independently evaluate this strain as a potential US emergency response vaccine. Ten, approximately four month-old lambs and calves were vaccinated with RVF MP-12 strain; two additional animals per species provided negative control specimens. The animals were monitored for clinical and immune response, fever, and viremia. Two animals per species were sacrificed on 2, 3, 4, 10 and 28 days post infection and full necropsies were performed for histopathological examination. No clinical or febrile responses were observed in this study. The onset and titer of the immune response is discussed. There was no significant histopathology in the lambs; however, 6 out of 10 vaccinated calves had multifocal, random areas of hepatocellular degeneration and necrosis. RVF MP12 antigen was detected in these areas of necrosis by immunohistochemistry in one calf. This study provides independent and baseline information on the RVF MP-12 attenuated vaccination in vaccine relevant age target species and indicates the importance of performing safety testing on vaccine relevant aged target animals.
Collapse
Affiliation(s)
- William C Wilson
- USDA-ARS Arthropod-Borne Animal Disease Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS 66502, USA.
| | - Bhupinder Bawa
- Diagnostic Medicine and Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Barbara S Drolet
- USDA-ARS Arthropod-Borne Animal Disease Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS 66502, USA
| | - Chris Lehiy
- USDA-ARS Arthropod-Borne Animal Disease Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS 66502, USA
| | - Bonto Faburay
- Diagnostic Medicine and Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Dane C Jasperson
- USDA-ARS Arthropod-Borne Animal Disease Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS 66502, USA
| | - Lindsey Reister
- USDA-ARS Arthropod-Borne Animal Disease Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS 66502, USA
| | - Natasha N Gaudreault
- USDA-ARS Arthropod-Borne Animal Disease Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS 66502, USA
| | - Jolene Carlson
- Diagnostic Medicine and Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Wenjun Ma
- Diagnostic Medicine and Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Igor Morozov
- Diagnostic Medicine and Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - D Scott McVey
- USDA-ARS Arthropod-Borne Animal Disease Research Unit (ABADRU), Center for Grain and Animal Health Research, Manhattan, KS 66502, USA
| | - Jürgen A Richt
- Diagnostic Medicine and Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| |
Collapse
|
32
|
Chengula AA, Kasanga CJ, Mdegela RH, Sallu R, Yongolo M. Molecular detection of Rift Valley fever virus in serum samples from selected areas of Tanzania. Trop Anim Health Prod 2014; 46:629-34. [PMID: 24464589 DOI: 10.1007/s11250-014-0540-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2014] [Indexed: 01/18/2023]
Abstract
Rift Valley fever (RVF) is an acute mosquito-borne viral zoonotic disease affecting domestic animals and humans caused by the Rift Valley fever virus (RVFV). The virus belongs to the genus Phlebovirus of the family Bunyaviridae. The main aim of this study was to detect the presence of antibodies to RVFV as well as the virus in the serum samples that were collected from livestock during the 2006/2007 RVF outbreaks in different locations in Tanzania. Analysis of selected samples was done using a RVF-specific inhibition enzyme-linked immunosorbent assay (I-ELISA) and reverse transcription polymerase chain reaction (RT-PCR). Genomic viral RNA was extracted directly from serum samples using a QIAamp Viral RNA Mini Kit (QIAGEN), and a one-step RT-PCR protocol was used to amplify the S segment of RVFV. Positive results were obtained in 39.5% (n = 200) samples using the RVF I-ELISA, and 17.6% (n = 108) of samples were positive by RT-PCR. I-ELISA detected 41 (38.7%), 32 (39.0%), and 6 (50.0%) positive results in cattle, goats, and sheep sera, respectively, whereas the RT-PCR detected 11 (0.2%), 7 (0.2%), and 1 (0.1%) positive results in cattle, goats, and sheep sera, respectively. These findings have demonstrated the presence of RVFV in Tanzania during the 2006/2007 RVF outbreaks. To our knowledge, this is the first report to detect RVFV in serum samples from domestic animals in Tanzania using PCR technique. Therefore, a detailed molecular study to characterize the virus from different geographical locations in order to establish the profile of strains circulating in the country and develop more effective and efficient control strategies should be done.
Collapse
Affiliation(s)
- Augustino Alfred Chengula
- Department of Veterinary Microbiology and Parasitology, Faculty of Veterinary Medicine, Sokoine University of Agriculture, P. O. Box 3019, Morogoro, Tanzania,
| | | | | | | | | |
Collapse
|