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Hungwe FTT, Laycock KM, Ntereke TD, Mabaka R, Paganotti GM. A historical perspective on arboviruses of public health interest in Southern Africa. Pathog Glob Health 2024; 118:131-159. [PMID: 38082563 PMCID: PMC11141323 DOI: 10.1080/20477724.2023.2290375] [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] [Indexed: 05/31/2024] Open
Abstract
Arboviruses are an existing and expanding threat globally, with the potential for causing devastating health and socioeconomic impacts. Mitigating this threat necessitates a One Health approach that integrates vector surveillance, rapid disease detection, and innovative prevention and control measures. In Southern Africa, limited data on the epidemiology of arboviruses, their vectors, and their hosts prevent an effective response. We reviewed the current knowledge on arboviruses in Southern Africa and identified opportunities for further research. A literature search was conducted to identify studies published on arboviruses in 10 tropical and temperate countries of the Southern African Development Community (SADC) from 1900 onward. We identified 280 studies, half (51.1%) originating from South Africa, that described 31 arboviral species, their vectors, and their clinical effects on hosts reported in the region. Arboviral research flourished in the SADC in the mid-20th century but then declined, before reemerging in the last two decades. Recent research consists largely of case reports describing outbreaks. Historical vector surveillance and serosurveys from the mid-20th century suggest that arboviruses are plentiful across Southern Africa, but large gaps remain in the current understanding of arboviral distribution, transmission dynamics, and public health impact.
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Affiliation(s)
- Faith T. T. Hungwe
- School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, Stockholm, Sweden
- Department of Molecular Medicine, Karolinska Institute, Stockholm, Sweden
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Katherine M. Laycock
- The Ryan White Center for Pediatric Infectious Disease and Global Health, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | | | - Rorisang Mabaka
- School of Allied Health Sciences, Faculty of Health Sciences, University of Botswana, Gaborone, Botswana
| | - Giacomo M. Paganotti
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana
- Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biomedical Sciences, University of Botswana, Gaborone, Botswana
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Comparison of RT-qPCR and RT-ddPCR with Rift valley fever virus (RVFV) RNA. Sci Rep 2023; 13:3085. [PMID: 36813787 PMCID: PMC9944419 DOI: 10.1038/s41598-023-29023-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/30/2023] [Indexed: 02/24/2023] Open
Abstract
Rift valley fever (RVF) is an important zoonotic disease caused by the Rift valley fever virus (RVFV) which can affect ruminants and humans. In this study, a comparison was done of the reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and reverse transcription-droplet digital PCR (RT-ddPCR) assays with synthesized RVFV RNA, cultured viral RNA, and mock clinical RVFV RNA samples. The genomic segments (L, M, and S) of three RVFV strains (BIME01, Kenya56, and ZH548) were synthesized and used as templates for in vitro transcription (IVT). Both the RT-qPCR and RT-ddPCR assays for RVFV did not react with any of the negative reference viral genomes. Thus, both the RT-qPCR and RT-ddPCR assays are specific to RVFV. The comparison of both the RT-qPCR and RT-ddPCR assays with serially diluted templates showed that the LoD of both assays are similar, and a concordant of the results was observed. The LoD of both assays reached the practical measurable minimum concentration. Taken altogether, the sensitivity of the RT-qPCR and RT-ddPCR assays is similar, and the material measured by RT-ddPCR can be used as a reference material for RT-qPCR.
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Lumley S, Hernández-Triana LM, Horton DL, Fernández de Marco MDM, Medlock JM, Hewson R, Fooks AR, Johnson N. Competence of mosquitoes native to the United Kingdom to support replication and transmission of Rift Valley fever virus. Parasit Vectors 2018; 11:308. [PMID: 29776384 PMCID: PMC5960175 DOI: 10.1186/s13071-018-2884-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/02/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rift Valley fever phlebovirus (RVFV) is a mosquito-borne arbovirus causing severe disease in humans and livestock. It is endemic in Africa and spread to the Arabian Peninsula in 2000 raising concerns it could emerge in Europe. The ability of temperate mosquitoes from the United Kingdom (UK) to support replication and transmission of RVFV is unknown. METHODS In this study, two colonised lines of Culex pipiens, wild-caught Aedes detritus and Ae. rusticus from the UK were infected with pathogenic strains of RVFV to assess their vector competence. Mosquitoes were offered artificial blood-meals containing 106 or 107 plaque forming units (PFU)/ml RVFV, simulating natural peak viraemia in young ruminants, and maintained at 20 °C or 25 °C for up to 21 days. Bodies, legs and saliva were collected and tested for the presence of viral RNA and infectious virus to determine the infection, dissemination and transmission potential. RESULTS Across temperatures, doses and strains the average infection, dissemination and transmission rates were: 35, 13 and 5% (n = 91) for Cx. pipiens (Caldbeck); 23, 14 and 5% (n = 138) for Cx. pipiens (Brookwood); 36, 28 and 7% (n = 118) for Ae. detritus. However, despite 35% (n = 20) being susceptible to infection, Ae. rusticus did not transmit RVFV. Survival of Aedes species was negatively affected by maintenance at 25 °C compared to the more representative peak average British summer temperature of 20 °C. Increased mortality was also observed with some species infected with 107 PFU/ml compared to 106 PFU/ml. CONCLUSIONS It can be concluded that temperate mosquito species present in the UK demonstrate a transmission potential for RVFV in the laboratory but, even at high temperatures, this occurred at low efficiency.
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Affiliation(s)
- Sarah Lumley
- Microbiology Services Division, Public Health England, Wiltshire, UK. .,School of Veterinary Medicine, University of Surrey, Guildford, UK. .,Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK.
| | - Luis M Hernández-Triana
- Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK
| | - Daniel L Horton
- School of Veterinary Medicine, University of Surrey, Guildford, UK
| | | | - Jolyon M Medlock
- Microbiology Services Division, Public Health England, Wiltshire, UK
| | - Roger Hewson
- Microbiology Services Division, Public Health England, Wiltshire, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
| | - Anthony R Fooks
- Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK.,NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK.,Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Liverpool, UK
| | - Nicholas Johnson
- School of Veterinary Medicine, University of Surrey, Guildford, UK.,Wildlife Zoonoses and Vector-borne Diseases Research Group, Animal and Plant Health Agency, Addlestone, Surrey, UK
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