Rift Valley fever (RVF) is a neglected vector-borne disease which is endemic in many countries across Africa and has seen recent geographical expansions into the Arabian Peninsula. RVF can cause severe infections in both animals and humans. RVF infections in livestock can lead to mass fatalities. In humans, the symptoms are nonspecific and can often lead to misdiagnosis. However, a small proportion progresses to haemorrhagic infection with a significantly higher mortality rate. The culmination of this can cause severe socioeconomic impacts. This review aims to identify the main socioeconomic impacts caused by RVF outbreaks as well as existing knowledge gaps. Ninety-three academic and grey papers were selected, covering 19 countries and 10 methodological approaches. A variety of socioeconomic impacts were found across all levels of society: Livestock trade disruptions consequently impacted local food security, local and national economies. Most livestock farmers in endemic countries are subsistence farmers and so rely on their livestock for sustenance and income. RVF outbreaks resulted in a variety of socioeconomic impacts, e.g., the inability to pay for school fees. Main barriers to vaccine uptake in communities were lack of access, funds, interest along with other social aspects. The occupational risks for women (and pregnant women) are largely unknown. To our knowledge, this is the first review on RVF to highlight the clear knowledge gap surrounding the potential gender differences on risks of RVF exposure, as well as differences on occupational health risk in pastoral communities. Further work is required to fill the gaps identified in this review and inform control policies.

BACKGROUND: In Africa, little is known about the role of telephone hotlines in outbreak response. We systematically reviewed the role and effectiveness of hotlines on outbreak response in Africa.
METHODS: We used the Cochrane handbook and searched five databases. The protocol was registered on PROSPERO (CRD42021247141). Medline, Embase, PsycINFO, Global Health and Web of Science were searched from 30 June 2020 to August 2020 for studies on the use of telephone hotlines in outbreak response in Africa published between January 1995 and August 2020. The search was also repeated on 16 September 2022. Data on effectiveness (alerts generated, cases confirmed) were extracted from peer-reviewed studies. Meta-analysis of alerts generated, and proportion of cases confirmed was done using the random effects model. The quality of studies was assessed using the Joanna Briggs Institute (JBI) tools. The heterogeneity and publication bias were assessed using the Galbraith and funnel plots, respectively.
RESULTS: Our search yielded 1251 non-duplicate citations that were assessed. 41 full texts were identified, and 21 studies were included in the narrative synthesis, while 12 were included in the meta-analysis. The hotlines were local (seven studies) or national (three studies). A combination of a local and national hotline was used in one study. The hotlines were set up for unusual respiratory events (one study), polio (one study), Ebola (10 studies), COVID-19 (two studies), malaria (one study), influenza-like illnesses (ILI) (one study) and rift valley fever in livestock (one study). Hotlines were mainly used for outbreak surveillance at the local level. A total of 332,323 alerts were generated, and 67,658 met the case definition, corresponding to an overall pooled proportion of alerts generated(sensitivity) of 38% (95%CI: 24-52%). The sensitivity was 41% (95% CI: 24-59%) for local hotlines and 26%(95%CI:5-47%) for national hotlines. Hotlines were also used for surveillance of rift valley fever in livestock (one study) vaccination promotion (one study), death reporting (five studies), rumour tracking and fighting misinformation (two studies) and community engagement (five studies). The studies were of low to moderate quality with high publication bias and heterogeneity(I2 = 99%). The heterogeneity was not explained by the sample size.
CONCLUSIONS: These data suggest that telephone hotlines can be effective in outbreak disease surveillance in Africa. Further implementation research is needed to scale up telephone hotlines in rural areas.

During the past four decades, recurrent outbreaks of various arthropod-borne viruses have been reported in Mauritania. This review aims to consolidate the current knowledge on the epidemiology of the major arboviruses circulating in Mauritania. Online databases including PubMed and Web of Science were used to retrieve relevant published studies. The results showed that numerous arboviral outbreaks of variable magnitude occurred in almost all 13 regions of Mauritania, with Rift Valley fever (RVF), Crimean-Congo hemorrhagic fever (CCHF), and dengue (DEN) being the most common infections. Other arboviruses causing yellow fever (YF), chikungunya (CHIK), o\'nyong-nyong (ONN), Semliki Forest (SF), West Nile fever (WNF), Bagaza (BAG), Wesselsbron (WSL), and Ngari (NRI) diseases have also been found circulating in humans and/or livestock in Mauritania. The average case fatality rates of CCHF and RVF were 28.7% and 21.1%, respectively. RVF outbreaks have often occurred after unusually heavy rainfalls, while CCHF epidemics have mostly been reported during the dry season. The central and southeastern regions of the country have carried the highest burden of RVF and CCHF. Sheep, cattle, and camels are the main animal reservoirs for the RVF and CCHF viruses. Culex antennatus and Cx. poicilipes mosquitoes and Hyalomma dromedarii, H. rufipes, and Rhipicephalus everesti ticks are the main vectors of these viruses. DEN outbreaks occurred mainly in the urban settings, including in Nouakchott, the capital city, and Aedes aegypti is likely the main mosquito vector. Therefore, there is a need to implement an integrated management strategy for the prevention and control of arboviral diseases based on sensitizing the high-risk occupational groups, such as slaughterhouse workers, shepherds, and butchers for zoonotic diseases, reinforcing vector surveillance and control, introducing rapid point-of-care diagnosis of arboviruses in high-risk areas, and improving the capacities to respond rapidly when the first signs of disease outbreak are identified.

Rift Valley fever (RVF) is a severe zoonotic mosquito-borne disease that represents an important threat to human and animal health, with major public health and socioeconomic impacts. This disease is endemic throughout many African countries and the Arabian Peninsula. This systematic review with meta-analysis was conducted to determine the RVF prevalence in humans, mosquitoes and other animal species in Africa. The review also provides contemporary data on RVF case fatality rate (CFR) in humans. In this systematic review with meta-analysis, a comprehensive literature search was conducted on the PubMed, Embase, Web of Science and Global Index Medicus databases from January 2000 to June 2022 to identify relevant studies. Pooled CFR and prevalence estimates were calculated using the random-effects model. Subgroup analysis and sensitivity analysis were performed, and the I2 -statistic was used to investigate a potential source of heterogeneity. A total of 205 articles were included in the final analysis. The overall RVF CFR in humans was found to be 27.5% [95% CI = 8.0-52.5]. The overall pooled prevalence was 7.8% [95% CI = 6.2-9.6] in humans and 9.3% [95% CI = 8.1-10.6] in animals, respectively. The RVF prevalence in individual mosquitoes ranged from 0.0% to 25%. Subgroup analysis showed substantial heterogeneity with respect to geographical regions and human categories. The study shows that there is a correspondingly similar prevalence of RVF in human and animals; however, human CFR is much higher than the observed prevalence. The lack of a surveillance programme and the fact that this virus has subclinical circulation in animals and humans could explain these observations. The implementation of a One Health approach for RVF surveillance and control would be of great interest for human and animal health.

Rift Valley fever (RVF) is a zoonotic arbovirosis which has been reported across Africa including the northernmost edge, South West Indian Ocean islands, and the Arabian Peninsula. The virus is responsible for high abortion rates and mortality in young ruminants, with economic impacts in affected countries. To date, RVF epidemiological mechanisms are not fully understood, due to the multiplicity of implicated vertebrate hosts, vectors, and ecosystems. In this context, mathematical models are useful tools to develop our understanding of complex systems, and mechanistic models are particularly suited to data-scarce settings. Here, we performed a systematic review of mechanistic models studying RVF, to explore their diversity and their contribution to the understanding of this disease epidemiology. Researching Pubmed and Scopus databases (October 2021), we eventually selected 48 papers, presenting overall 49 different models with numerical application to RVF. We categorized models as theoretical, applied, or grey, depending on whether they represented a specific geographical context or not, and whether they relied on an extensive use of data. We discussed their contributions to the understanding of RVF epidemiology, and highlighted that theoretical and applied models are used differently yet meet common objectives. Through the examination of model features, we identified research questions left unexplored across scales, such as the role of animal mobility, as well as the relative contributions of host and vector species to transmission. Importantly, we noted a substantial lack of justification when choosing a functional form for the force of infection. Overall, we showed a great diversity in RVF models, leading to important progress in our comprehension of epidemiological mechanisms. To go further, data gaps must be filled, and modelers need to improve their code accessibility.

Certain \"exotic\" viruses are known to cause clinical diseases with potential liver involvement. These include viruses, beyond regular hepatotropic viruses (hepatitis A, -B(D), -C, -E, cytomegalovirus, Epstein-Barr virus), that can be found in (sub)tropical areas and can cause \"exotic viral hepatitis\". Transmission routes typically involve arthropods (Crimean Congo haemorrhagic fever, dengue, Rift Valley fever, yellow fever). However, some of these viruses are transmitted by the aerosolised excreta of rodents (Hantavirus, Lassa fever), or via direct contact or contact with bodily fluids (Ebola). Although some exotic viruses are associated with high fatality rates, such as Ebola for example, the clinical presentation of most exotic viruses can range from mild flu-like symptoms, in most cases, right through to being potentially fatal. A smaller percentage of people develop severe disease with haemorrhagic fever, possibly with (fulminant) hepatitis. Liver involvement is often caused by direct tropism for hepatocytes and Kupffer cells, resulting in virus-mediated and/or immune-mediated necrosis. In all exotic hepatitis viruses, PCR is the most sensitive diagnostic method. The determination of IgM/IgG antibodies is a reasonable alternative, but cross-reactivity can be a problem in the case of flaviviruses. Licenced vaccines are available for yellow fever and Ebola, and they are currently under development for dengue. Therapy for exotic viral hepatitis is predominantly supportive. To ensure that preventive measures can be introduced to control possible outbreaks, the timely detection of these viruses is very important.

Rwanda is located in the Central East African region where several viral pathogens with global importance were originally described, including human immunodeficiency virus (HIV), Ebola, Zika, Rift Valley Fever (RVF), dengue and a long list of other neglected tropical viral pathogens. Due to many factors, this region has the potential to become a global hotspot for viral emergence. In Rwanda, viral diseases are underreported and the question is whether this is due to the absence of these viruses or a lack of investigation. Like many developing countries, capabilities in Rwanda need improvement despite research efforts throughout the years. This review describes the status of human and animal virus research in Rwanda and identifies relevant research and operational gaps. A comprehensive search was conducted in PubMed for virus research in Rwanda: 233 primary studies on viruses/viral diseases are indexed with connection to Rwanda. From 1958 to 2020, yearly publications generally increased and HIV/acquired immunodeficiency syndrome is the most studied virus. Compared with human viruses, few studies focus on animal and/or zoonotic viruses. The occurrence of the current severe acute respiratory syndrome coronavirus 2 pandemic shows strengthening warning and surveillance systems is critical to efficient preparedness and response. We recommend investment in human capacity, laboratory facilities and research to inform policy for viral surveillance in Rwanda.

Rift Valley fever (RVF) is an emerging, neglected, mosquito-borne viral zoonosis associated with significant morbidity, mortality and expanding geographical scope. The clinical signs and symptoms in humans are non-specific and case definitions vary. We reviewed and analysed the clinical manifestations of RVF in humans.
In this systematic review and meta-analysis we searched on different dates, the Embase (from 1947 to 13th October 2019), Medline (1946 to 14th October 2019), Global Health (1910 to 15th October 2019), and Web of Science (1970 to 15th October 2019) databases. Studies published in English, reporting frequency of symptoms in humans, and laboratory confirmed RVF were included. Animal studies, studies among asymptomatic volunteers, and single case reports for which a proportion could not be estimated, were excluded. Quality assessment was done using a modified Hoy and Brooks et al tool, data was extracted, and pooled frequency estimates calculated using random effects meta-analysis.
Of the 3765 articles retrieved, less than 1% (32 articles) were included in the systematic review and meta-analysis. Nine RVF clinical syndromes were reported including the general febrile, renal, gastrointestinal, hepatic, haemorrhagic, visual, neurological, cardio-pulmonary, and obstetric syndromes. The most common clinical manifestations included fever (81%; 95% Confidence Interval (CI) 69-91; [26 studies, 1286 patients]), renal failure (41%; 23-59; [4, 327]), nausea (38%; 12-67; [6, 325]), jaundice (26%; 16-36; [15, 393]), haemorrhagic disease (26%; 17-36; [16, 277]), partial blindness (24%; 7-45; [11, 225]), encephalitis (21%; 11-33; [4, 327]), cough (4%; 0-17; [4, 11]), and miscarriage (54%) respectively. Death occurred in 21% (95% CI 14-29; [16 studies, 328 patients]) of cases, most of whom were hospitalised.
This study delineates the complex symptomatology of human RVF disease into syndromes. This approach is likely to improve case definitions and detection rates, impact outbreak control, increase public awareness about RVF, and subsequently inform \'one-health\' policies. This study provides a pooled estimate of the proportion of RVF clinical manifestations alongside a narrative description of clinical syndromes. However, most studies reviewed were case series with small sample sizes and enrolled mostly in-patients and out-patients, and captured symptoms either sparsely or using broad category terms.

Rift Valley fever (RVF) is a serious life-threatening disease with severe clinical manifestations and health consequences for humans and a wide range of domestic animals. In September 2000, an RVF outbreak was reported in the Jazan region in the south-west part of Saudi Arabia with 886 human cases including 124 deaths. This review provides: a) an overview of the RVF control programme in Saudi Arabia, and b) an assessment of some of the control measures that have been launched since the early recognition of RVF. Currently, with the exception of Saudi Arabia, devastating outbreaks of RVF continue to occur and the number of countries reporting cases has increased rapidly. At least 19 large outbreaks including substantial numbers of human and animal deaths have been reported for the period between 2000 and 2018. In contrast to the aforementioned situation in endemic areas, the RVF control programme that was set up in Saudi Arabia has completely reversed the risk of re-occurrence of RVF over the past 18 years and provided long-term protection against Rift Valley fever virus (RVFV) exposure. The control programme involved: a) vector control campaigns (using conventional and microbial insecticides, drainage and filling of water swamps with soil, and mosquito surveillance) and b) host-driven controls such as sustained vaccination campaigns, regular examination of sentinel herds, including seasonal surveillance reinforcement (targeted sero-surveillance during rainy seasons), and serological examination of clandestine animal imports kept at Al-Twal quarantine station, at the border with Yemen. The effectiveness of the current control programme can be demonstrated not only by the decrease in antibody prevalence of RVF virus-specific immunoglobulin M, from 12.3% (95% confidence interval [CI]: 6.8-17.8) in 2000 to 0.10% (95% CI: 0.01-0.2) in 2017, but also by the absence of human and animal cases since the 2000 outbreak. The mosquito infection rates with RVFV have also declined, from 0.045 per 1,000 for the genus Culex in 2014 to zero from 2015 to 2018. Additionally, the integrated vector management methods targeting outdoor habitats in the Jazan region substantially contributed to vector control and should be considered one of the most important factors contributing to the significant reduction of malaria case incidence from 2000 to 2014. The Saudi current control initiative could be used as a guideline for control of RVF or as a suitable model for other endemic countries.
La fièvre de la vallée du Rift (FVR) est une maladie grave, parfois mortelle, qui provoque d\'importantes manifestations cliniques et affecte la santé humaine ainsi que celle de nombreuses espèces d\'animaux domestiques. En septembre 2000, un foyer de FVR a été signalé dans la région de Jazan, dans le sud-ouest de l\'Arabie saoudite, avec 886 cas humains déclarés, dont 124 décès. Les auteurs présentent les résultats d\'une étude de synthèse portant sur : a) le programme de contrôle de la FVR mis en place par l\'Arabie saoudite ; et b) l\'évaluation de certaines mesures de contrôle parmi celles qui ont été appliquées depuis la détection précoce de la FVR dans le pays. Actuellement, en dehors de l\'Arabie saoudite qui constitue une exception, des foyers dévastateurs de FVR continuent de se déclarer et le nombre de pays signalant des cas augmente rapidement. Au moins 19 foyers majeurs ayant entraîné un nombre important de décès chez l\'homme comme chez les animaux ont été signalés durant la période de 2000 à 2018. Contrairement à la situation observée dans ces zones d\'endémie, en Arabie saoudite le programme de lutte contre la FVR s\'est traduit par une inversion complète du risque de nouveaux foyers au cours des 18 années écoulées et a apporté une protection durable contre l\'exposition au virus de la FVR. Le programme de lutte comprenait les éléments suivants : a) des campagnes de lutte contre les vecteurs (utilisation d\'insecticides traditionnels et microbiens, drainage et remblaiement des marécages, surveillance des populations de moustiques) ; et b) des mesures de contrôle axées sur les populations hôtes, en particulier des campagnes de vaccination soutenues, un examen régulier des troupeaux sentinelles, un renforcement de la surveillance saisonnière (surveillance sérologique ciblée pendant la saison des pluies) et un dépistage sérologique des animaux importés clandestinement et maintenus dans la station de quarantaine d\'Al-Twal, à la frontière avec le Yémen. L\'efficacité du programme de contrôle actuel peut être démontrée non seulement par la diminution de la prévalence des anticorps sériques d\'immunoglobuline M spécifiques du virus de la FVR, qui est passée de 12,3 % (intervalle de confiance [IC] à 95 % : 6,8-17,8) en 2000 à 0,10 % (IC à 95 % : 0,01-0,2) en 2017, mais aussi par l\'absence de cas humains et animaux depuis le foyer de 2000. Les taux d\'infection des moustiques par le virus de la FVR ont également diminué, passant de 0,045 pour 1 000 chez le moustique du genre Culex en 2014, à zéro infection de 2015 à 2018. De plus, les méthodes de gestion intégrée des vecteurs appliquées dans les habitats extérieurs ont largement contribué à la lutte antivectorielle dans la région de Jazan et peuvent être considérées comme l\'un des principaux facteurs de la baisse significative de l\'incidence des cas de paludisme de 2000 à 2014. L\'initiative saoudienne de lutte contre la FVR pourrait servir de fil conducteur des stratégies de contrôle de cette maladie, voire de modèle applicable par d\'autres pays où elle sévit à l\'état endémique.
La fiebre del valle del Rift (FVR) es una grave enfermedad, a veces mortal, que tiene graves manifestaciones clínicas y consecuencias sanitarias para el ser humano y diversos animales domésticos. En septiembre de 2000 se notificó un brote de FVR en la región de Jizán (en el sudoeste de Arabia Saudí) que afectó a 886 personas, de las cuales fallecieron 124. En este artículo los autores: a) presentan una síntesis del programa de lucha contra la FVR en Arabia Saudí; y b) valoran algunas de las medidas de control implantadas desde que se empezó a detectar la enfermedad. Actualmente, con la excepción de Arabia Saudí, siguen produciéndose devastadores brotes de FVR y va en rápido aumento el número de países que notifican casos. En los años que van de 2000 a 2018 se han comunicado al menos 19 brotes de grandes proporciones, que han causado la muerte de un número considerable de personas y animales. En contraste con esta situación reinante en zonas de endemicidad, en los últimos 18 años el programa de lucha que se instauró en Arabia Saudí ha invertido completamente el riesgo de resurgencia de la enfermedad y ofrecido protección duradera contra la exposición al virus de la FVR. Este programa se declina en: a) campañas de lucha contra el vector (con empleo de insecticidas convencionales y microbianos, drenaje y relleno de zonas pantanosas y vigilancia de las poblaciones de mosquitos); y b) controles de las poblaciones de hospedadores, por ejemplo mediante campañas sostenidas de vacunación, inspecciones periódicas de rebaños centinela, con vigilancia reforzada en ciertas épocas (serovigilancia específica en las temporadas de lluvias), y análisis serológicos de los animales importados clandestinamente y mantenidos en el centro de cuarentena de Al-Twal, situado en la frontera con el Yemen. De la eficacia del vigente programa de lucha, dan fe no solo la caída de la prevalencia de inmunoglobulinas M dirigidas específicamente contra el virus de la FVR, que pasó de un 12,3% (intervalo de confianza [IC] al 95%: 6,8-17,8) en 2000 a un 0,10% (IC 95%: 0,01-0,2) en 2017, sino también la ausencia de casos en humanos y animales desde el brote del año 2000. También ha disminuido la tasa de infección de mosquitos por el virus de la FVR, que pasó de 0,045 por 1 000 ejemplares del género Culex en 2014 a cero entre 2015 y 2018. Además, los métodos de lucha antivectorial integrada aplicados en hábitats al aire libre de la región de Jizán contribuyeron sustancialmente al control del vector. En este sentido, conviene ver estas medidas como uno de los principales factores que han influido en la sustancial reducción de la incidencia de casos de paludismo entre 2000 y 2014. La iniciativa saudí actualmente en curso podría servir de guía para combatir la FVR o como modelo adecuado para otros países donde la enfermedad es endémica.

Rift Valley fever virus (RVFV) is a lethal threat to humans and livestock in many parts of Africa, the Arabian Peninsula, and the Indian Ocean. This systematic review\'s objective was to consolidate understanding of RVFV epidemiology during 1999-2021 and highlight knowledge gaps relevant to plans for human vaccine trials.
The review is registered with PROSPERO (CRD42020221622). Reports of RVFV infection or exposure among humans, animals, and/or vectors in Africa, the Arabian Peninsula, and the Indian Ocean during the period January 1999 to June 2021 were eligible for inclusion. Online databases were searched for publications, and supplemental materials were recovered from official reports and research colleagues. Exposures were classified into five groups: 1) acute human RVF cases, 2) acute animal cases, 3) human RVFV sero-surveys, 4) animal sero-surveys, and 5) arthropod infections. Human risk factors, circulating RVFV lineages, and surveillance methods were also tabulated. In meta-analysis of risks, summary odds ratios were computed using random-effects modeling. 1104 unique human or animal RVFV transmission events were reported in 39 countries during 1999-2021. Outbreaks among humans or animals occurred at rates of 5.8/year and 12.4/year, respectively, with Mauritania, Madagascar, Kenya, South Africa, and Sudan having the most human outbreak years. Men had greater odds of RVFV infection than women, and animal contact, butchering, milking, and handling aborted material were significantly associated with greater odds of exposure. Animal infection risk was linked to location, proximity to water, and exposure to other herds or wildlife. RVFV was detected in a variety of mosquito vectors during interepidemic periods, confirming ongoing transmission.
With broad variability in surveillance, case finding, survey design, and RVFV case confirmation, combined with uncertainty about populations-at-risk, there were inconsistent results from location to location. However, it was evident that RVFV transmission is expanding its range and frequency. Gaps assessment indicated the need to harmonize human and animal surveillance and improve diagnostics and genotyping. Given the frequency of RVFV outbreaks, human vaccination has strong potential to mitigate the impact of this now widely endemic disease.