Community of practice on sanitary and phytosanitary risk assessment: a step towards a national risk assessment agency?

With 106.057 ZAR Billion in 2018 (current prices) agriculture represented 2.44% of the GDP of South Africa. Despite this relatively small contribution to the national wealth agriculture remains one of the main employment provider of the country particularly in rural areas as well as a major earner of foreign exchange through international trade. This activity is regulated by sanitary and phytosanitary (SPS) measures that require an effectively regulated framework and technical expertise in risk assessments. To provide a supportive and seamless trade framework for the country a Community of Practice (CoP) model has been funded by the National Research Foundation (NRF) supported by the Department of Agriculture, Forestry and Fisheries (DAFF) to support government in high level strategic negotiations and positioning and support industry to prevent the introduction and spread of major pests and pathogens in plant, animal and public health. This CoP aligns with the Veterinary Strategy Plan which stipulated the needs for a national agency to define, coordinate and develop risk analysis (RA) in the field of sanitary, phytosanitary, environmental and occupational risk assessment. The primary research objective of the CoP SPS RA framework will be to assess the risks associated with, and to develop and test surveillance, diagnostic and control models to detect the emergence of, selected plant diseases, insect pests, animal diseases and animal health-related conditions, including zoonoses, food borne diseases, chemical residues, mycotoxins and antimicrobial resistance. The second objective of the CoP is to train postgraduate students and government regulators in RA and advanced epidemiology and diagnostics, thus building human capacity. The third objective will be to provide government and other stakeholders with relevant information and scientific advice on the risk of emergence, entry and spread of diseases in SA in order to facilitate inter-sectorial coordination mechanisms at national and regional level to respond to SPS issues. This CoP, with the development of collaborations and relationships, will build some strategic partnerships with the local and international scientific community in the areas of SPS Risk Assessments. It will provide scientific coordination of expert committees set up by DAFF and provide technical support for the establishment of the sanitary agency proposed in the Veterinary Strategy. In the longer term and with the establishment of this national SPS Agency/Authority, South Africa will meet it international commitments to the WTO in terms of Codex, IPCC, OIE rules and regulations, as risk assessment is one of these commitments

Appui scientifique et technique en épidémiologie et sur l'analyse du risque zoonotique de la tuberculose (Mycobacterium bovis, Mycobacterium tuberculosis) et de la brucellose : mission du 23 mars au 1er avril 2004

Cette mission est la deuxième du Cirad-Emvt en Ouganda cette année 2004. Cette mission a été programmée suite à une décision commune prise entre l'ambassade de France en Ouganda et l'agent Cirad-Emvt en place en Ouganda. Son objectif était de faire une première évaluation sur la faisabilité technique et institutionnelle d'une analyse de risque sur deux zoonoses majeures, la tuberculose et la brucellose, cette évaluation intéressant la composante 2 du projet FSP "Concertation agricole et structuration des filières". Dans cette optique, il convenait notamment de catalyser le travail de PhD d'un chercheur ougandais de l'Université de Mbarara. Ainsi outre un approfondissement sur la problématique abordée dans ce PhD, il convenait de tracer les lignes directrices qui pourraient constituer l'architecture de cette thèse, d'activer le démarrage du travail en particulier en rencontrant les différents partenaires potentiels désireux de s'inscrire dans ce travail. Parallèlement une réflexion devait être menée sur l'aspect zoonotique de la brucellose. Il s'agissait également d'apporter un appui scientifique dans le cadre de formation en épidémiologie à mettre en place par l'agent Cirad au sein des Universités de Makéréré et de Mbarara. (Résumé d'auteur

Cross species transmission of Mycobacterium bovis infection at the wildlife/livestock interface in South Africa

Bovine tuberculosis affects cattle in South Africa and is known to be endemic in wildlife with the African buffalo (Syncerus caffer) being recognized as the maintenance host. Spoligotyping and mycobacteria interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) genotyping methods were performed to investigate the molecular characteristics of Mycobacterium bovis (M. bovis) isolates from cattle and wildlife, their distribution and transmission at the wildlife/livestock interface in northern kwa-Zulu Natal (KZN), South Africa. DNA was extracted from microbiological cultures of milk, nasal and tissue samples from bTB positive cattle and tissue samples from bTB infected wildlife. Spoligotyping and Mycobacterial Interspersed Repetitive Units-Variable Tandem Repeats (MIRU-VNTR) on 13 loci was used for molecular characterisation of the M. bovis isolates. SB0130 was identified as the dominant spoligotype pattern at the wildlife/livestock interface, while VNTR typing revealed a total of 29 VNTR profiles in the KZN province signifying genetic variability. The detection of 5 identical VNTR profiles in cattle and buffalo suggests M. bovis transmission between species. MIRU-VNTR confirmed co-infection in one cow with three strains of M. bovis implying introduction of infection from unrelated sources. Our findings highlight inter and intra species transmission of bovine tuberculosis at the wildlife/livestock interface and the need for the implementation of adequate bTB control measures to mitigate the spread of the pathogen

Epidemiological surveillance methods for vector-borne diseases

Compared with many other diseases, the ever-increasing threat of vectorborne diseases (VBDs) represents a great challenge to public and animal health managers. Complex life cycles, changing distribution ranges, a variety of potential vectors and hosts, and the possible role of reservoirs make surveillance for VBDs a grave concern in a changing environment with increasing economic constraints. Surveillance activities may have various specific objectives and may focus on clinical disease, pathogens, vectors, hosts and/or reservoirs, but ultimately such activities should improve our ability to predict, prevent and/or control the diseases concerned. This paper briefly reviews existing and newly developed tools for the surveillance of VBDs. A range of examples, by no means exhaustive, illustrates that VBD surveillance usually involves a combination of methods to achieve its aims, and is best accomplished when these techniques are adapted to the specific environment and constraints of the region. More so than any other diseases, VBDs respect no administrative boundaries; in addition, animal, human and commodity movements are increasing dramatically, with illegal or unknown movements difficult to quantify. Vector-borne disease surveillance therefore becomes a serious issue for local and national organisations and is being conducted more and more at the regional and international level through multidisciplinary networks. With economic and logistical constraints, tools for optimising and evaluating the performance of surveillance systems are essential and examples of recent developments in this area are included. The continuous development of mapping, analytical and modelling tools provides us with an enhanced ability to interpret, visualise and communicate surveillance results. This review also demonstrates the importance of the link between surveillance and research, with interactions and benefits in both directions. (Résumé d'auteur

Risk assessment scenarios to understand the persistence of Rift Valley fever in Comoros (Indian Ocean)

Rift Valley Fever (RVF) is an arbozoonosis identified for the first time in Kenya in the 1930s. In 2000, the first apparition of the virus out of Africa was described in the Arabian Peninsula with both animal and human cases. Indian Ocean showed animal and human cases in 2008 in Madagascar where the disease was absent during 17 years while the same year the same year the first human case was diagnosed in Mayotte from a young Comorian. Lots of models described climate drivers of RVF outbreaks. These models failed to predict malagasy outbreaks. These recent spreads of the disease are likely to be also linked with animal movements. Forecasting outbreaks and managing rapid control of the disease request adapted and more flexible models. This study assessed two scenarios of risk in the Comoros Islands and compared the results with some surveillance data in order to determine the potential role of the introduction of an exogenous hazard. The first scenario explored the endemicity of the disease through insect-borne transmission and developed the probability for the disease to be spread throughout the island because of infectious mosquito bites. The second scenario developed a model with new legal introduction of cattle from Tanzania and subsequent contact and infection of bovines in Comoros (Grande Comores). A quantitative stochastic approach permitted to include variability as well as uncertainty in this quantitative risk assessment. Advanced analysis of the sensitivity of the models allowed to explore the most probable pathways of transmission and therefore to define thresholds to set priorities in the RVF surveillance and the control measures. (Texte intégral

Transmission of foot and mouth disease at the wildlife/livestock interface of the Kruger National Park, South Africa: can the risk be mitigated?

In Southern Africa, the African buffalo (Syncerus caffer) is the natural reservoir of foot and mouth disease (FMD). Contacts between this species and cattle are responsible for most of the FMD outbreaks in cattle at the edge of protected areas, which generate huge economic losses. During the late 1980's and 90's, the erection of veterinary cordon fences and the regular vaccination of cattle exposed to buffalo contact at the interface of the Kruger National Park (KNP), proved to be efficient to control and prevent FMD outbreaks in South Africa. However, since 2000, the efficiency of those measures has deteriorated, resulting in an increased rate of FMD outbreaks in cattle outside KNP, currently occurring more than once a year. Based on retrospective ecological and epidemiological data, we developed a stochastic quantitative model to assess the annual risk of FMD virus (FMDV) transmission from buffalo to cattle herds present at the KNP interface. The model suggests that good immunization of approximately 75% of the cattle population combined with a reduction of buffalo/cattle contacts is an efficient combination to reduce FMDV transmission to one infective event every 5.5 years, emulating the epidemiological situation observed at the end of the 20th century, before current failure of control measures. The model also indicates that an increasing number of buffalo present in the KNP and crossing its boundaries, combined with a reduction in the vaccination coverage of cattle herds at the interface, increases 3-fold the risk of transmission (one infective event per year).The model proposed makes biological sense and provides a good representation of current knowledge of FMD ecology and epidemiology in Southern Africa which can be used to discuss with stakeholders on different management options to control FMD at the wildlife livestock interface and updated if new information becomes available. It also suggests that the control of FMD at the KNP interface is becoming increasingly challenging and will probably require alternative approaches to control this disease and its economic impact. (Résumé d'auteur

Risk analysis and bovine tuberculosis in developing countries

Bovine tuberculosis (BTB) can have a dramatic impact on an economy and on human and animal health. Over the past two decades, BTB has received increasing attention due to its sustained high prevalence among animal populations. Infected animals and animal products pose a significant risk to humans. This is particularly true in developing countries with immunocompromised individuals, mostly HIV-infected, and in communities where human consumption of raw milk is widespread and meat inspection is rudimentary. The maintenance of wild game reserves and the persistence of infection in livestock in these countries also increase the risk of BTB transmission to humans. Greater cooperation between animal services and public health agencies is necessary. Within this context, the use of quantitative risk analysis (QRA) should facilitate the assessment, management, and mitigation of the risk of BTB transmission from domestic and wild animals to humans. Drawing from field surveys in Uganda, QRA models were developed that took into account the various transmissions' pathways e.g. milk, meat, bushmeat, and animal clinical cases. Local knowledge, gathered through participatory epidemiological surveys among farmers and consumers, and the opinions of experts were considered to better evaluate QRA inputs. The use of risk analysis should be promoted as a decision-making tool and in policy-making processes to improve animal and public health in developing countries. The final goal is to develop pro-poor strategies aiming to improve food safety and decrease the likelihood of zoonoses in order to protect consumers and to keep markets open to smallholder livestock keepers. (Résumé d'auteur

Risk analysis in animal health: threat or opportunity for Africa?

Risk analysis originated in the aerospace industry following the loss of life due to a fire on Apollo flight AS-204 in 1967. The tool was later developed in the nuclear industry for the reactor safety. It reached the animal health sector through the Sanitary and Phytosanitary (SPS) agreement signed in 1994 during the Marrakech agreement of the General Agreement on Tariffs and Trade (GATT). The SPS agreement entered into force with the establishment of the World Trade Organization (WTO) on 1 January 1995. The SPS agreement recognises the World Organisation for Animal Health (OIE) as the relevant international organization entrusted with the development of import risk analysis techniques in animal health. The (appropriate) level of protection that countries imposed to avoid ingress of highly infectious diseases through restriction of imports had to be based on scientific principles (i.e. risk analysis). Development of risk analysis studies requires available data, teamwork, as well as specific skills. One can understand the impact of such studies in terms of access to market for specific commodities and in terms of protection against transboundary diseases introduction. We assessed the extent to which risk analysis is used in Africa in compliance with OIE standards and guidelines, through a study based on two approaches. A questionnaire evaluating the capacity, capacity building and the risk assessment studies produced or received was carried out through all the African countries. In parallel, the risk analysis section of evaluation reports produced by OIE in almost all African countries as part of the Performance of Veterinary Services (PVS) pathway was analysed. Results allowed us to draw a picture of the situation in Africa regarding the use of this very technical tool as well as to formulate some recommendations to improve the sanitary protection and the access of African countries to international markets. (Texte intégral