scholarly journals The epidemiology and socio-economic impact of Rift Valley fever epidemics in Tanzania: A review

2012 ◽  
Vol 79 (2) ◽  
Author(s):  
Calvin Sindato ◽  
Esron Karimuribo ◽  
E.G. Mboera
Keyword(s):  
Economic Impact ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Climatic Factors ◽  
Large Population ◽  
Economic Losses ◽  
Extensive Literature ◽  
Animal Movements ◽  
Valley Fever ◽  
Socio Economic Impact

A review was conducted to provide comprehensive update on Rift Valley fever (RVF) in Tanzania, with particular attention devoted to trend of occurrence, epidemiological factors, socio-economic impact and measures which were applied to its control. Information presented in this paper was obtained through extensive literature review. Rift Valley fever was documented for the first time in Tanzania in 1977. This was followed by epidemics in 1997 and 2007. Contrary to the latest epidemic in 2007 sporadic cases of RVF during the previous epidemics were confined to mainly livestock and mostly affecting northern parts of Tanzania. The latest disease epidemic expanded to cover wider areas (mostly northern and central zones) of the country involving both human and domestic ruminants. During the latest disease outbreak 52.4% (n = 21) of regions in Tanzania mainland were affected and majority (72.7, n = 11) of the regions had concurrent infections in human and animals. Phylogenetic comparison of nucleotide and amimo acid sequences revealed different virus strains between Kenya and Tanzania.Epidemiological factors that were considered responsible for the previous RVF epidemics in Tanzania included farming systems, climatic factors, vector activities and presence of large population of ruminant species, animal movements and food consumption habits. Majority of the RVF positive cases in the latest epidemic were livestock under pastoral and agro-pastoral farming systems.The disease caused serious effects on rural people’s food security and household nutrition and on direct and indirect losses to livestock producers in the country. Psycho-social distress that communities went through was enormous, which involved the thinking about the loss of their family members and/or relatives, their livestock and crop production. Socially, the status of most livestock producers was eroded in their communities.Cessation of lucrative trade in ruminants resulted in serious economic losses to the populations who were totally dependent upon this income. Livestock internal market flows drastically dropped by 37% during latest epidemic. Rift Valley fever epidemics had dramatic impact of RVF outbreak on the international animal trade in which there was a 54% decline in exports equivalent to loss of $352 750.00. The estimate of loss as a result of deaths for cattle was $4 243 250.00 whereas that of goats and sheep was $2 202 467.00.Steps taken to combat epidemics included restriction of animal movements, ban of the slaughter of cattle and vaccination of livestock and health education.From past epidemics we have learnt that each subsequent outbreak had expanded to cover wider areas of the country. The disease had dramatic socio-economic impacts both at community and nation at large. The main challenges related to the control of RVF outbreaks included lack of preparedness plan for RVF, poor coordination and information transmission, limited facilities and manpower for RVF outbreak intervention. Control of the 2007 RVF epidemic was largely the result of animal and human health agencies working in an integrated manner.

scholarly journals A Systematic Scoping Study of the Socio‐Economic Impact of Rift Valley Fever: Research Gaps and Needs

2014 ◽  
Vol 62 (5) ◽  
pp. 309-325 ◽  
Author(s):  
M. Peyre ◽  
V. Chevalier ◽  
S. Abdo‐Salem ◽  
A. Velthuis ◽  
N. Antoine‐Moussiaux ◽  
...  
Keyword(s):  
Economic Impact ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Research Gaps ◽  
Valley Fever ◽  
Scoping Study ◽  
Socio Economic Impact

scholarly journals The Change P82L in the Rift Valley Fever Virus NSs Protein Confers Attenuation in Mice Not Related with a Type-I IFN Antagonistic Phenotype

2021 ◽  
Author(s):  
Belén Borrego ◽  
Sandra Moreno ◽  
Nuria de la Losa ◽  
Friedemann Weber ◽  
Alejandro Brun
Keyword(s):  
Amino Acid ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Fever Virus ◽  
Single Amino Acid ◽  
Economic Losses ◽  
Type I ◽  
Valley Fever

Rift valley fever virus (RVFV) is a mosquito-borne bunyavirus that causes an important disease in ruminants, with great economic losses. The infection can be also transmitted to humans; therefore it is considered a major threat to both human and animal health. In a previous work, we described a novel RVFV variant selected in cell culture in the presence of the antiviral agent favipiravir that was highly attenuated in vivo. This variant displayed 24 amino acid substitutions in different viral proteins when compared to its parental viral strain, two of them located in the NSs protein that is known to be the major virulence factor of RVFV. By means of a reverse genetics system, in this work we have analyzed the effect that one of these substitutions, P82L, has in viral attenuation in vivo. Rescued viruses carrying this single amino acid change were clearly attenuated in BALB/c mice while their growth in an IFN-competent cell line as well as the production of IFN-β did not seem to be affected. However, the pattern of nuclear NSs accumulation was modified in cells infected with the mutant viruses. These results unveil a new RVFV virulence marker highlighting the multiple ways of NSs protein to modulate viral infectivity.

scholarly journals Over 100 Years of Rift Valley Fever: A Patchwork of Data on Pathogen Spread and Spillover

Pathogens ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 708
Author(s):  
Gebbiena M. Bron ◽  
Kathryn Strimbu ◽  
Hélène Cecilia ◽  
Anita Lerch ◽  
Sean M. Moore ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Economic Losses ◽  
Valley Fever ◽  
Critical Data ◽  
The Past ◽  
Data Gaps ◽  
Combined Data

During the past 100 years, Rift Valley fever virus (RVFV), a mosquito-borne virus, has caused potentially lethal disease in livestock, and has been associated with significant economic losses and trade bans. Spillover to humans occurs and can be fatal. Here, we combined data on RVF disease in humans (22 countries) and animals (37 countries) from 1931 to 2020 with seroprevalence studies from 1950 to 2020 (n = 228) from publicly available databases and publications to draw a more complete picture of the past and current RVFV epidemiology. RVFV has spread from its original locus in Kenya throughout Africa and into the Arabian Peninsula. Throughout the study period seroprevalence increased in both humans and animals, suggesting potentially increased RVFV exposure. In 24 countries, animals or humans tested positive for RVFV antibodies even though outbreaks had never been reported there, suggesting RVFV transmission may well go unnoticed. Among ruminants, sheep were the most likely to be exposed during RVF outbreaks, but not during periods of cryptic spread. We discuss critical data gaps and highlight the need for detailed study descriptions, and long-term studies using a one health approach to further convert the patchwork of data to the tale of RFV epidemiology.

scholarly journals Perceived risk factors and risk pathways of Rift Valley fever in cattle in Ijara district, Kenya

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Nelson O. Owange ◽  
William O. Ogara ◽  
Jacqueline Kasiiti ◽  
Peter B. Gathura ◽  
Sam Okuthe ◽  
...  
Keyword(s):  
Risk Factors ◽  
Perceived Risk ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Close Contact ◽  
Economic Losses ◽  
Cross Sectional ◽  
Valley Fever ◽  
Key Informants ◽  
Control And Prevention

Ijara district in Kenya was one of the hotspots of Rift Valley fever (RVF) during the 2006/2007 outbreak, which led to human and animal deaths causing major economic losses. The main constraint for the control and prevention of RVF is inadequate knowledge of the risk factors for its occurrence and maintenance. This study was aimed at understanding the perceived risk factors and risk pathways of RVF in cattle in Ijara to enable the development of improved community-based disease surveillance, prediction, control and prevention. A cross-sectional study was carried out from September 2012 to June 2013. Thirty-one key informant interviews were conducted with relevant stakeholders to determine the local pastoralists’ understanding of risk factors and risk pathways of RVF in cattle in Ijara district. All the key informants perceived the presence of high numbers of mosquitoes and large numbers of cattle to be the most important risk factors contributing to the occurrence of RVF in cattle in Ijara. Key informants classified high rainfall as the most important (12/31) to an important (19/31) risk factor. The main risk pathways were infected mosquitoes that bite cattle whilst grazing and at watering points as well as close contact between domestic animals and wildlife. The likelihood of contamination of the environment as a result of poor handling of carcasses and aborted foetuses during RVF outbreaks was not considered an important pathway. There is therefore a need to conduct regular participatory community awareness sessions on handling of animal carcasses in terms of preparedness, prevention and control of any possible RVF epizootics. Additionally, monitoring of environmental conditions to detect enhanced rainfall and flooding should be prioritised for preparedness.

scholarly journals Modelling the persistence and control of Rift Valley fever virus in a spatially heterogeneous landscape

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Warren S. D. Tennant ◽  
Eric Cardinale ◽  
Catherine Cêtre-Sossah ◽  
Youssouf Moutroifi ◽  
Gilles Le Godais ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Animal Movement ◽  
Rift Valley Fever Virus ◽  
Virus Transmission ◽  
Control Measures ◽  
Environmental Drivers ◽  
Animal Movements ◽  
Valley Fever ◽  
The Impact

AbstractThe persistence mechanisms of Rift Valley fever (RVF), a zoonotic arboviral haemorrhagic fever, at both local and broader geographical scales have yet to be fully understood and rigorously quantified. We developed a mathematical metapopulation model describing RVF virus transmission in livestock across the four islands of the Comoros archipelago, accounting for island-specific environments and inter-island animal movements. By fitting our model in a Bayesian framework to 2004–2015 surveillance data, we estimated the importance of environmental drivers and animal movements on disease persistence, and tested the impact of different control scenarios on reducing disease burden throughout the archipelago. Here we report that (i) the archipelago network was able to sustain viral transmission in the absence of explicit disease introduction events after early 2007, (ii) repeated outbreaks during 2004–2020 may have gone under-detected by local surveillance, and (iii) co-ordinated within-island control measures are more effective than between-island animal movement restrictions.

scholarly journals Rift Valley fever - a threat for Europe?

2010 ◽  
Vol 15 (10) ◽  
Author(s):  
V Chevalier ◽  
M Pépin ◽  
L Plée ◽  
R Lancelot
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Large Scale ◽  
Large Population ◽  
Diagnostic Methods ◽  
Monitoring And Control ◽  
Valley Fever ◽  
Control Programmes ◽  
Eastern And Southern Africa ◽  
And Control

Rift Valley fever (RVF) is a severe mosquito-borne disease affecting humans and domestic ruminants, caused by a Phlebovirus (Bunyaviridae). It is widespread in Africa and has recently spread to Yemen and Saudi Arabia. RVF epidemics are more and more frequent in Africa and the Middle East, probably in relation with climatic changes (episodes of heavy rainfall in eastern and southern Africa), as well as intensified livestock trade. The probability of introduction and large-scale spread of RVF in Europe is very low, but localised RVF outbreaks may occur in humid areas with a large population of ruminants. Should this happen, human cases would probably occur in exposed individuals: farmers, veterinarians, slaughterhouse employees etc. Surveillance and diagnostic methods are available, but control tools are limited: vector control is difficult to implement, and vaccines are only available for ruminants, with either a limited efficacy (inactivated vaccines) or a residual pathogenic effect. The best strategy to protect Europe and the rest of the world against RVF is to develop more efficient surveillance and control tools and to implement coordinated regional monitoring and control programmes.

scholarly journals The One Health Approach is Necessary for the Control of Rift Valley Fever Infections in Egypt: A Comprehensive Review

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 139 ◽  
Author(s):  
Mohamed Fawzy ◽  
Yosra A. Helmy
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
One Health ◽  
Economic Stress ◽  
Current Status ◽  
Economic Losses ◽  
High Morbidity ◽  
Valley Fever ◽  
The One ◽  
And Control

Rift Valley fever (RVF) is an emerging transboundary, mosquito-borne, zoonotic viral disease caused high morbidity and mortality in both human and ruminant populations. It is considered an important threat to both agriculture and public health in African and the Middle Eastern countries including Egypt. Five major RVF epidemics have been reported in Egypt (1977, 1993, 1994, 1997, and 2003). The virus is transmitted in Egypt by different mosquito's genera such as Aedes, Culex, Anopheles, and Mansonia, leading to abortions in susceptible animal hosts especially sheep, goat, cattle, and buffaloes. Recurrent RVF outbreaks in Egypt have been attributed in part to the lack of routine surveillance for the virus. These periodic epizootics have resulted in severe economic losses. We posit that there is a critical need for new approaches to RVF control that will prevent or at least reduce future morbidity and economic stress. One Health is an integrated approach for the understanding and management of animal, human, and environmental determinants of complex problems such as RVF. Employing the One Health approach, one might engage local communities in surveillance and control of RVF efforts, rather than continuing their current status as passive victims of the periodic RVF incursions. This review focuses upon endemic and epidemic status of RVF in Egypt, the virus vectors and their ecology, transmission dynamics, risk factors, and the ecology of the RVF at the animal/human interface, prevention, and control measures, and the use of environmental and climate data in surveillance systems to predict disease outbreaks.

scholarly journals A dynamic, climate-driven model of Rift Valley fever

2016 ◽  
Vol 11 (1s) ◽  
Author(s):  
Joseph Leedale ◽  
Anne E. Jones ◽  
Cyril Caminade ◽  
Andrew P. Morse
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Climatic Factors ◽  
Model Development ◽  
Eastern Africa ◽  
Climate Data ◽  
Valley Fever ◽  
Model Driven ◽  
Spatio Temporal ◽  
The Impact

Outbreaks of Rift Valley fever (RVF) in eastern Africa have previously occurred following specific rainfall dynamics and flooding events that appear to support the emergence of large numbers of mosquito vectors. As such, transmission of the virus is considered to be sensitive to environmental conditions and therefore changes in climate can impact the spatiotemporal dynamics of epizootic vulnerability. Epidemiological information describing the methods and parameters of RVF transmission and its dependence on climatic factors are used to develop a new spatio-temporal mathematical model that simulates these dynamics and can predict the impact of changes in climate. The Liverpool RVF (LRVF) model is a new dynamic, process-based model driven by climate data that provides a predictive output of geographical changes in RVF outbreak susceptibility as a result of the climate and local livestock immunity. This description of the multi-disciplinary process of model development is accessible to mathematicians, epidemiological modellers and climate scientists, uniting dynamic mathematical modelling, empirical parameterisation and state-of-the-art climate information.

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