Rift Valley Fever – epidemiological update and risk of introduction into Europe
2020; Wiley; Volume: 18; Issue: 3 Linguagem: Inglês
10.2903/j.efsa.2020.6041
ISSN1831-4732
AutoresSøren Saxmose Nielsen, Julio Álvarez, Dominique Bicout, Paolo Calistri, Klaus Depner, Julian Ashley Drewe, Bruno Garin‐Bastuji, José Luis Gonzales Rojas, Christian Gortázar, Virginie Michel, Miguel Ángel Miranda Chueca, Helen Clare Roberts, Liisa Sihvonen, Karl Ståhl, Antonio Velarde, Arvo Viltrop, Christoph Winckler, Bernard Bett, Catherine Cêtre-Sossah, Véronique Chevalier, Clazien Devos, Simon Gubbins, Federica Monaco, Sotiria‐Eleni Antoniou, Alessandro Broglia, José Cortiñas Abrahantes, Sofie Dhollander, Yves Van der Stede, Gabriele Zancanaro,
Tópico(s)Viral Infections and Outbreaks Research
ResumoEFSA JournalVolume 18, Issue 3 e06041 Scientific OpinionOpen Access Rift Valley Fever – epidemiological update and risk of introduction into Europe Søren Saxmose Nielsen, Corresponding Author alpha@efsa.europa.eu Correspondence: alpha@efsa.europa.euSearch for more papers by this authorJulio Alvarez, Search for more papers by this authorDominique Joseph Bicout, Search for more papers by this authorPaolo Calistri, Search for more papers by this authorKlaus Depner, Search for more papers by this authorJulian Ashley Drewe, Search for more papers by this authorBruno Garin-Bastuji, Search for more papers by this authorJosé Luis Gonzales Rojas, Search for more papers by this authorChristian Gortázar Schmidt, Search for more papers by this authorVirginie Michel, Search for more papers by this authorMiguel Ángel Miranda Chueca, Search for more papers by this authorHelen Clare Roberts, Search for more papers by this authorLiisa Helena Sihvonen, Search for more papers by this authorKarl Stahl, Search for more papers by this authorAntonio Velarde Calvo, Search for more papers by this authorArvo Viltrop, Search for more papers by this authorChristoph Winckler, Search for more papers by this authorBernard Bett, Search for more papers by this authorCatherine Cetre-Sossah, Search for more papers by this authorVeronique Chevalier, Search for more papers by this authorClazien Devos, Search for more papers by this authorSimon Gubbins, Search for more papers by this authorFederica Monaco, Search for more papers by this authorAntoniou Sotiria-Eleni, Search for more papers by this authorAlessandro Broglia, Search for more papers by this authorJosé Cortiñas Abrahantes, Search for more papers by this authorSofie Dhollander, Search for more papers by this authorYves Van Der Stede, Search for more papers by this authorGabriele Zancanaro, Search for more papers by this author Søren Saxmose Nielsen, Corresponding Author alpha@efsa.europa.eu Correspondence: alpha@efsa.europa.euSearch for more papers by this authorJulio Alvarez, Search for more papers by this authorDominique Joseph Bicout, Search for more papers by this authorPaolo Calistri, Search for more papers by this authorKlaus Depner, Search for more papers by this authorJulian Ashley Drewe, Search for more papers by this authorBruno Garin-Bastuji, Search for more papers by this authorJosé Luis Gonzales Rojas, Search for more papers by this authorChristian Gortázar Schmidt, Search for more papers by this authorVirginie Michel, Search for more papers by this authorMiguel Ángel Miranda Chueca, Search for more papers by this authorHelen Clare Roberts, Search for more papers by this authorLiisa Helena Sihvonen, Search for more papers by this authorKarl Stahl, Search for more papers by this authorAntonio Velarde Calvo, Search for more papers by this authorArvo Viltrop, Search for more papers by this authorChristoph Winckler, Search for more papers by this authorBernard Bett, Search for more papers by this authorCatherine Cetre-Sossah, Search for more papers by this authorVeronique Chevalier, Search for more papers by this authorClazien Devos, Search for more papers by this authorSimon Gubbins, Search for more papers by this authorFederica Monaco, Search for more papers by this authorAntoniou Sotiria-Eleni, Search for more papers by this authorAlessandro Broglia, Search for more papers by this authorJosé Cortiñas Abrahantes, Search for more papers by this authorSofie Dhollander, Search for more papers by this authorYves Van Der Stede, Search for more papers by this authorGabriele Zancanaro, Search for more papers by this author First published: 06 March 2020 https://doi.org/10.2903/j.efsa.2020.6041Citations: 2 Requestor: European Commission Question number: EFSA-Q-2019-00422 Panel members: Søren Saxmose Nielsen, Julio Alvarez, Dominique Joseph Bicout, Paolo Calistri, Klaus Depner, Julian Ashley Drewe, Bruno Garin-Bastuji, Jose Luis Gonzales Rojas, Christian Gortázar Schmidt, Virginie Michel, Miguel Ángel Miranda Chueca, Helen Clare Roberts, Liisa Helena Sihvonen, Karl Stahl, Antonio Velarde Calvo, Arvo Viltrop and Christoph Winckler. Acknowledgements: The EFSA Panel on Animal Health and Welfare wishes to thank the following for the support provided to this scientific output: Laure Dommergues, Claire Donohue, Laura Gonzalez Villeta. The Panel wishes to acknowledge all European competent institutions, Member State bodies and other organisations that provided data for this scientific output: Dr Hüseyin Yilmaz, Veterinary Faculty of the University of Istanbul,Turkey; Clémence Bourély, Laëtitia Thibaudeau and Séverine Rautureau, Direction générale de l'alimentation, Ministère de l'Agriculture et de l'Alimentation, France; Mahmoud Mohamed Ali Abdelhakim and Mariem Magdy, Ministry of Agriculture and Land Reclamation, Egypt; Riham Bassam and Elias Ibrahim, Ministry of Agriculture, Lebanon; Mahmoud Al Hanatleh, Ministry of Agriculture, Jordan. Adopted: 23 January 2020 This article was originally published on the EFSA website www.efsa.europa.eu on 4 March 2020 AboutSectionsPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat 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. Summary No RVF outbreaks in humans or animals have been reported in Europe or in European Union (EU) neighbouring countries so far, although RVF reappeared after 10 years in a French overseas Department (Mayotte) with outbreaks involving multiple human cases in 2018–2019. Besides this reoccurrence, a legislative process triggered a mandate from the European Commission to European Food Safety Authority (EFSA) to perform a risk assessment on RVF. The Commission adopted a draft Commission Delegated Regulation which supplements Part III of Regulation (EU) 2016/429 (Animal Health Law), laying down rules for the prevention and control of transmissible animal diseases, and that replaces existing Directives, such as Directive 92/119/EEC which currently provides for measures to apply in the event of occurrence of certain diseases, which includes RVF. Additionally, in accordance with Commission Implementing Regulation (EU) 2019/1882, RVF is categorised as a Category A disease. Following the categorisation and the proposed changes to the measures for RVF, the Commission requested a complete risk assessment on RVF (risk of introduction, exposure and effectiveness of prevention and control measures), since the measures proposed in the Delegated Regulation should be based on the latest scientific knowledge. In particular, it was requested to provide an update of the global epidemiological situation in relation to RVF with emphasis on areas posing a higher risk for the EU. Moreover, the overall risk of introduction of RVF into the EU (combining rate of entry, RVFV transmission and establishment) should be assessed at regional level (considering the EU regions as specified in a 2017 EFSA scientific opinion on vector-borne diseases) and for each single MS. Regarding the recent epidemics in Mayotte the probability of overwintering of RVF, the risk of RVF spreading from Mayotte to other areas as well as the impact of the disease on animal health and farm production should be assessed. Additionally, the assessment of effectiveness of preventive and control measures in eliminating or reducing the disease impact in Mayotte as well as different surveillance strategies in animals that may be used for detection and possible prediction of RVF recurrence in Mayotte should be carried out. Finally, while considering the risk of RVF introduction into the EU, the surveillance measures for early detection of the disease as well as the feasibility, availability and effectiveness of the prevention and control measures for RVF should be evaluated, especially the ones foreseen in the above-mentioned Commission Delegated Regulation. The present opinion deals with the update of the global epidemiological situation in relation to RVF with emphasis on areas posing a higher risk for the EU and with an assessment of the overall risk of introduction of RVF into the EU. Two further scientific outputs will be produced to address the other requested points. For the update on the global epidemiological situation of RVF, descriptive statistics and information from the literature and national authorities were used. Outbreak data from World Organisation for Animal Health (OIE), Animal Disease Notification System (ADNS), WHO, trade data from EUROSTAT and UN COMtrade and information obtained by French authorities and OIE representatives in Middle East were collected and considered. Rift Valley fever is a vector-borne disease transmitted by a broad spectrum of mosquito species, Aedes and Culex genus being the most relevant, to animals (domestic and wild ruminants, camels) and humans. RVF has been present historically in Africa in sub-Saharan areas and in specific zones of the Arabian Peninsula, on the border between Saudi Arabia and Yemen. Historically, in these endemic areas, major RVF epidemics have been periodically observed, usually with long inter-epizootic periods (5–15 years) during which the virus was not detected in domestic animal populations. In the last two decades, some changes in the RVF epidemiology were recorded: more evidence has been observed on the spread of RVFV into new African areas, not regarded as infected before, even in locations considered not optimal for mosquito-borne diseases, like Sahel areas. Moreover, regarding RVF recurrence, epidemics have been recorded more frequently and low-level enzootic RVFV circulation in livestock has been demonstrated in various areas. Outbreaks in a French overseas department and some seropositive cases detected in Turkey and Tunisia raised concerns for the EU regarding a possible incursion into countries neighbouring continental EU and/or with direct trade links. Positive serological findings in Algeria, Western Sahara, Tunisia, Libya, Iraq, Iran, Turkey, which are or were countries considered officially free from RVF, must be carefully interpreted on the bases of the study designs and diagnostic tests used. However, the repeated detection of serological positive individuals (animals or humans) in these countries must be seen as a signal of a potential risk of RVF spread out of its endemic geographical area. In this regard, the movement of live animals is the main risk factor for RVF spread from the African endemic areas. Several pathways of livestock movements between sub-Saharan and North African countries can be identified. Moreover, the trade from the Horn of Africa towards the Arabian Peninsula and Middle East involves several millions of live animals each year, thus representing a constant risk of RVF introduction into the Middle East. Among available diagnostic tools, molecular assays for RVFV detection are available and, more recently, a pen-side test for early detection of viraemic animals. Serological tests to detect RVF antibodies that are able to distinguish early from past RVFV infection in domestic ruminants are also available. As for the EU preparedness, the diagnostic capacity of laboratories among EU Member countries and in the Mediterranean region has been assessed and the level of performance considered adequate as well as in National Laboratories from Algeria, Mauritania, Morocco, Tunisia, Mali and Senegal. Nevertheless, an evaluation of the performance of diagnostic tests in place in most of the other Mediterranean countries should be encouraged through inter-laboratory trials. Regarding vaccines against RVF, no vaccines have been authorised for use in the EU. However, both live-attenuated and inactivated vaccines are commercially available for RVF and have contributed significantly to the control of RVF in endemic countries. Some limitations are linked to the need of repeated vaccinations for inactivated vaccines, and some safety issues arise for the live-attenuated vaccines. Novel DIVA vaccines, including accompanying DIVA tests, are in the final stages of validation. The risk of introduction of RVFV into EU was assessed by using a model already presented in an earlier risk assessment by EFSA (2017) for 36 vector-borne diseases. This model is called MINTRISK (Method to INTegrate all relevant RISK aspects) and allows the assessment of the risk of introduction, transmission and impact of vector-borne diseases in a systematic, semi-quantitative way, and can be used for risk evaluation, risk comparison and risk ranking of possible vector-borne diseases of livestock. The risk of introduction of RVF assessed by MINTRISK derives from the combination of the rate of entry (of the pathogen), level of transmission (as the basic reproduction number) and probability of establishment of RVF in the EU (the chance for RVF to be further transmitted, linked to the presence of susceptible hosts and conditions), along the relevant pathways of introduction of the disease. First, the possible pathways for RVF introduction were reviewed. The role of infected animals, infected vectors, contaminated products and infected humans was considered; and it was concluded that the movement of infected animals (legally traded or uncontrolled movements) and of infected vectors by active flight or their passive transport when shipped by flights, containers or road transport could be considered as plausible pathways of introduction and were therefore further considered in the assessment. The rate of RVFV entry into the EU through the entry of infected animals is assessed as 'very low' (considering the scale of qualitative assessment of MINTRISK, which corresponds, in the worst-case scenario, to one entry every 500 years), this is linked to the strict trade rules on animal import, which basically prevent any import of animals from RVF-affected countries, whereas through the introduction of infected vectors is considered 'low' for France (median: 0.000282 entries/year; CI: 8.9*10−7; 0.056), Germany (median: 0.000251 entries/year; CI: 3.9*10-7;0.11) and the Netherlands (median: 0.000251 entries/year; CI: 10−6; 0.056), due to the greater number of connections by air and sea transports with African RVF-infected countries. Due to the level of uncertainty, other countries (Cyprus, Denmark, Luxembourg, Malta, Portugal) showed greater rates of entry of vectors (up to 0.06 entries per year) when the upper 95% confidence values are considered. This level of uncertainty is linked to the number of air and sea connections between affected countries and MSs, especially the maritime connections which generate higher uncertainty for the survival of mosquitoes at the destination. For all MS, the level of transmission (referred as the R0, basic reproduction number) has been assessed as 'moderate'. This is linked to the presence of RVF competent vectors in all MS, the same estimated value of the basic reproduction ratio for all MSs and full susceptibility of animal hosts in all MS. The probability of the establishment of RVFV transmission, once introduced, varies among the EU MS according to the introduction pathway considered: for the introduction through infected animals, a 'very high' probability (median 0.28, confidence interval, CI: 0.11–0.70) of RVFV transmission has been estimated for Greece, Malta and Portugal, 'high to very high' for Cyprus (median: 0.1, CI:0.02–0.35) and Italy (median: 0.1, CI:0.02–0.35); 'high' probability is considered for Belgium (median: 0.028, CI:0.01–0.071) and the Netherlands (median: 0.028, CI:0.011–0.071); 'moderate to high' for Croatia (median: 0.01, CI:0.002–0.039) and France (median: 0.01, CI:0.002–0.035. For the introduction through infected vectors, a 'very high' probability of RVFV transmission is assessed for Belgium, Greece, Malta and the Netherlands, 'high to very high' for United Kingdom, a 'high' probability is reported for Luxembourg, Portugal, and 'moderate to high' for Cyprus, Ireland, Italy. The differences observed between probability estimates according to the two introduction pathways (animal or vector) are mainly due to differences in host density among the countries and the climatic conditions, which are inputs for the estimation of probability of the first transmission step following the introduction of infected vectors. For the overall rate of introduction of RVF into the EU, through the animal pathway, the risk of RVF introduction is very low for all the EU MSs (less than 0.002 epidemics/year, meaning at least one epidemic in 500 years), given the strict health policies in place in the EU on the import of live animals from RVF-infected Third Countries and due to the long distance between the countries actually infected by RVF and the EU borders. For the vector pathway of introduction, the risk is very low for the great majority of MSs, but it is very low to low, when considering the median values, for Netherlands with 0.0044 epidemics/year (CI: 2.51*10−5; 1.58), meaning one epidemic every 227 years, followed by Malta with 0.0025 epidemics/year (CI: 5.62*10−6; 0.1.25), Belgium and Greece (0.0014 epidemics/year, CI: 4.47*10−6; 0.39, one epidemic every 700 years). In the worst-case scenario, and considering the uncertainty around these values (upper confidence intervals), some MS may have higher risk of RVF introduction (0.04 epidemics/year for Belgium, Greece, Luxemburg, Portugal and UK), and Netherlands and Malta may have one epidemic per year. This is mainly linked to the number of connections by air and sea transports with African RVF-infected countries. Considering the four EU regions (northern, southern, western and eastern EU), all of them are categorised as having a very low risk of introduction of RVF, for the Southern region a median of 0.002 epidemics/year (CI: 1.84*10−4−0.028), in the Western region 0.002 epidemics/year (CI: 1.35*10−4−0.03), in the Northern region 0.00086 epidemics/year (CI: 1.22*10-5−0.0205), in the Eastern region 2.8*10−5 epidemics/year (CI: 5.71*10−7−0.0011). From the above conclusions, the following can be recommended. Considering the possible future source of risks represented by the spread of infection into new areas closer to the EU borders, it is of paramount importance for the EU to establish and maintain a close collaboration with North African and Middle Eastern countries in the surveillance of possible introduction of RVF from currently infected areas, as well as to carefully monitor the evolution of the epidemics in African countries. Although the EU territory does not seem to be directly exposed to an imminent risk of RVFV introduction, the evolutions observed in the global situation of RVF occurrence, the risk of further spread of infection into countries closer to EU borders and the risks linked to the possible introduction of infected vectors, suggest EU authorities should strengthen, improve and harmonise their surveillance and response capacities as well as their scientific and technical expertise to be better prepared in case of RVFV introduction. Considering the higher risk of introduction associated with the introduction of infected vectors, it is recommended to integrate the surveillance systems already in place in the EU for invasive mosquitoes, taking into account the main possible points of entry of RVFV-infected vectors. Particular attention should be given to those countries that receive major air and sea traffic from RVF-affected countries. Disinsection procedures (spraying insecticides) in flights are compulsory in some cases and widely recommended by WHO and IATA. However, data about the efficacy of the treatments conducted in airplanes and ships in order to avoid the entry of vectors arriving from RVF-affected countries, are currently lacking. Finally, considering a possible introduction of RVFV in the EU, information about the potential mosquito vector species associated with livestock premises and the surrounding environment will be essential to develop adequate protocols for vector control. 1 Introduction 1.1 Background and Terms of Reference as provided by the European Commission General introduction and background information Rift Valley Fever (RVF) is a disease affecting primarily domestic and wild ruminants (cattle, sheep, goats), and camels. RVF is caused by a single-stranded RNA virus of the genus Bunyaviridae. RVF is a vector-borne disease, transmitted primarily through various species of vectors (mainly hematophagous mosquitoes). Certain species of vectors (e.g. Aedes mosquitoes) may act as reservoirs of the disease during inter-epidemic periods thanks to their potential for transovarian (vertical) transmission of the virus to their eggs. As a result, new generations of RVFV-infected mosquitoes may hatch from infected eggs, especially in periods of favourable conditions (e.g. high rainfalls). Susceptible animals are infected primarily by vector bites. Clinical signs range from sudden death or abortion to mild, non-specific symptoms, depending on the virulence of the virus strain and the species, breed and age of the affected animals. Mortality may reach 70–100% in lambs and kids, and 20–70% in adult sheep and calves. Abortion rates may reach 85–100% within the affected herds. RVF in camels can cause abortions and neonatal deaths. Infected wild ruminants usually do not show any clinical signs. Humans can become infected by the RVF virus (RVFV), through the bites of vectors, by contact with infected animals and animal materials (blood, discharges, abortion materials etc.) or by consumption of untreated animal products (meat and milk). No human-to-human transmission has been recorded to date. About 50% of infected humans have no clinical signs while others may experience flu-like symptoms. A small percentage may develop severe clinical forms, involving haemorrhagic fever with hepatic disease, meningoencephalitis or ocular complications. The total case fatality rate varies between different epidemics (overall less than 1% in those documented). To date, no RVF outbreaks in humans or animals have been reported in continental Europe or countries sharing land borders with the continental areas of the EU. The closest RVF evidence available are limited to serological findings from retrospective studies, carried out in Turkey, using blood samples collected from camels, gazelles and buffaloes from 2000 to 2006. Currently, the disease is endemic in large areas of Southern and Eastern Africa, where outbreaks of RVF occur periodically (e.g. every few years), in seasons when weather conditions favour competent vectors. In recent decades, large RVF epidemics have occurred in Egypt (1977-78, 1993, 2003), Mauritania (2010, 2012, 2015), Madagascar (2007-2009), Comoros (2007) and elsewhere in the African continent (Kenya, Somalia, South Africa, Sudan, Senegal etc.). Egypt and Libya currently marks the northernmost limit of RVF spread. The disease moved outside the African continent for the first time in 2000, into the Arab peninsula (Saudi Arabia and Yemen). On 5 April 2017, EFSA, following a request from the Commission, adopted a scientific opinion on 36 vector-borne diseases, including RVF. The opinion concluded that the risk of introduction of RVF in the EU was estimated to be very low based on a semi-quantitative method (modified MINTRISK model). In Mayotte, a French department in the Indian Ocean, close to the Union of the Comoros islands and Madagascar, human cases of RVF were detected for the first time in 2007. Retrospective serological studies demonstrated the presence of RVF in livestock since 2004 (serological evidence). Until recently, the disease appeared to be in remission with no new human cases detected since 2011. However, in 2018, RVF reappeared in Mayotte and between 22 November 2018 and 14 March 2019, more than 101 human cases and more than 60 outbreaks in ruminants have been reported. In response to the RVF resurgence, the competent authorities of Mayotte have been implementing surveillance and biosecurity measures, coupled with vector control/protection measures, aiming to limit the overall disease spread and prevent animal-to-human transmission. In addition, movements of ruminants and raw meat and milk thereof, originating from Mayotte, have been prohibited. The Commission is empowered to adopt delegated acts supplementing the rules laid down in Part III of Regulation (EU) 2016/429 on transmissible animal diseases (Animal Health Law) on disease control measures for listed diseases as referred to in point (a), (b) and (c) of its Article 9 (category A, B and C diseases). Therefore, a draft Commission Delegated Regulation laying down rules for the prevention and control of certain diseases has been developed and the draft is in consultation. The rules laid down in the above-mentioned draft Commission Delegated Regulation are largely 'taking over' the rules currently in force concerning the disease control measures in the event of animal diseases with serious effects on the livestock as they have proven to be effective in preventing the spread of those diseases within the Union. Consequently, animal disease control measures laid down in existing Directives will be, to the extent that not already done by the Animal Health Law, replaced by the rules provided in that Delegated Regulation. This is also the case of Directive 92/119/EEC which currently provides for measures to apply in the event of occurrence of certain diseases. This includes Rift Valley fever, which is in accordance with Commission Implementing Regulation (EU) 2019/1882, categorised as Category A disease. In this regard, the existing rules of Directive 92/119/EEC will cease to apply, in particular for Rift Valley fever, as from the date of application of the Animal Health Law and its complementing legislation, i.e. from 21 April 2021. The proposed measures for the prevention and control of RVF should be assessed in order to ensure that they are updated based on the latest scientific knowledge in this new set of legislation. Terms of Reference RISK OF ENTRY OF RVF INTO THE CONTINENTAL PARTS OF THE EU 1.1 Provide an update of the global epidemiological situation in relation to RVF with emphasis on areas posing a higher risk for the EU. 1.2 Provide an updated assessment of the overall risk of introduction of RVF (combined rate of entry, vector transmission and establishment), separately for each one of the EU regions potentially at risk, as specified in the 2017 EFSA scientific opinion on Vector-borne diseases (VBD). 1.3 Provide a separate risk assessment of the risk of introduction of RVF for specific Member States that may be at particular risk. 2 IMPACT OF RVF IN THE DEPARTMENT OF MAYOTTE AND RELEVANT CONTROL MEASURES 2.1 Assess the probability of overwintering of RVF in the department of Mayotte as well as the risk of RVF spreading from Mayotte to other areas including other French departments in the Indian Ocean or Metropolitan France. 2.2 Assess the impact of the disease (as defined in the 'VBD opinion'), with emphasis on animal health and farm production in Mayotte from the time of its initial occurrence to date. 2.3 Assess the possible short and long-term effectiveness, of different control measures, in eliminating or reducing the disease impact in Mayotte (as per TOR 2.2 above), namely: 2.3.1 Stamping out of RVF outbreaks; 2.3.2 Establishment of a protection and a surveillance zone around RVF outbreaks; 2.3.3 Biosecurity
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