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Although currently available data indicate that Africa has the lowest usage of antimicrobials in animals in the world (adjusted by animal biomass), data show a high prevalence of antimicrobial resistance in foodborne pathogens isolated from animals and animal products. Apart from the lack of solid data on antimicrobial use in many countries in Africa, different hypotheses could explain this situation. Qualitative interviews of farmers show a lack of knowledge and uninformed use of antimicrobials. Considering the development of animal farming to meet an increasing demand for proteins, this deficiency represents a serious public health issue. We advocate for policies that consider the specific challenges faced by family farmers in Africa, to simultaneously improve access to veterinary drugs while strengthening the regulation of their use. We propose a global approach targeting the agri-food system, offering innovative social and technical interventions on antimicrobial usage, adapted to family farmers.

The epidemic of COVID-19 has shown different developments in Africa compared to the other continents. Three different approaches were used in this study to analyze this situation. In the first part, basic statistics were performed to estimate the contribution of the elderly people to the total numbers of cases and deaths in comparison to the other continents; Similarly, the health systems capacities were analysed to assess the level of underreporting. In the second part, differential equations were reconstructed from the epidemiological time series of cases and deaths (from the John Hopkins University) to analyse the dynamics of COVID-19 in seventeen countries. In the third part, the time evolution of the contact number was reconstructed since the beginning of the outbreak to investigate the effectiveness of the mitigation strategies. Results were compared to the Oxford stringency index and to the mobility indices of the Google Community Mobility Reports. Compared to Europe, the analyses show that the lower proportion of elderly people in Africa enables to explain the lower total numbers of cases and deaths by a factor of 5.1 on average (from 1.9 to 7.8). It corresponds to a genuine effect. Nevertheless, COVID-19 numbers are effectively largely underestimated in Africa by a factor of 8.5 on average (from 1.7 to 20. and more) due to the weakness of the health systems at country level. Geographically, the models obtained for the dynamics of cases and deaths reveal very diversified dynamics. The dynamics is chaotic in many contexts, including a situation of bistability rarely observed in dynamical systems. Finally, the contact number directly deduced from the epidemiological observations reveals an effective role of the mitigation strategies on the short term. On the long term, control measures have contributed to maintain the epidemic at a low level although the progressive release of the stringency did not produce a clear increase of the contact number. The arrival of the omicron variant is clearly detected and characterised by a quick increase of interpeople contact, for most of the African countries considered in the analysis.

The unexpected Ebola virus outbreak in West Africa in 2014 involving the Zaire ebolavirus made clear that other regions outside Central Africa, its previously documented niche, were at risk of future epidemics. The complex transmission cycle and a lack of epidemiological data make mapping areas at risk of the disease challenging. We used a Geographic Information System-based multicriteria evaluation (GIS-MCE), a knowledge-based approach, to identify areas suitable for Ebola virus spillover to humans in regions of Guinea, Congo and Gabon where Ebola viruses already emerged. We identified environmental, climatic and anthropogenic risk factors and potential hosts from a literature review. Geographical data layers, representing risk factors, were combined to produce suitability maps of Ebola virus spillover at the landscape scale. Our maps show high spatial and temporal variability in the suitability for Ebola virus spillover at a fine regional scale. Reported spillover events fell in areas of intermediate to high suitability in our maps, and a sensitivity analysis showed that the maps produced were robust. There are still important gaps in our knowledge about what factors are associated with the risk of Ebola virus spillover. As more information becomes available, maps produced using the GIS-MCE approach can be easily updated to improve surveillance and the prevention of future outbreaks.

To clarify the role of bats in the ecology of Ebola viruses, we assessed the prevalence of Ebola virus antibodies in a large-scale sample of bats collected during 2015–2017 from countries in Africa that have had previous Ebola outbreaks (Guinea, the Democratic Republic of the Congo) or are at high risk for outbreaks (Cameroon). We analyzed 4,022 blood samples of bats from >12 frugivorous and 27 insectivorous species; 2–37 (0.05%–0.92%) bats were seropositive for Zaire and 0–30 (0%–0.75%) bats for Sudan Ebola viruses. We observed Ebola virus antibodies in 1 insectivorous bat genus and 6 frugivorous bat species. Certain bat species widespread across Africa had serologic evidence of Zaire and Sudan Ebola viruses. No viral RNA was detected in the subset of samples tested (n = 665). Ongoing surveillance of bats and other potential animal reservoirs are required to predict and prepare for future outbreaks.

INTRODUCTION: Viral hepatitis B remains a major public health problem around the world, especially in underdeveloped and developing countries. Cameroon shows a grate variability in prevalence of this infection in the country and even within different populations groups. The aim of this study was to determine the prevalence and factors associated with viral hepatitis B infection in the rural area of Dschang. METHODS: We conducted a cross-sectional community-based study, involving 551 participants of both genders recruited by a voluntary sampling technique. The biological diagnosis of HBsAg was done by the Immunochromatographic method (PKL® kit of PARAMEDICAL srl laboratories). Positive cases were confirmed by ELISA method (reagent Kit from DIALAB Laboratories). RESULTS: Results show a Viral Hepatitis B prevalence of 5.08% (95% CI: 3.2-6.9). University students were the most infected (11/88) with a positivity rate of 12.50% (95%CI: 5.6-19.4). Only 29/551 participants (5.26%) had received at least one dose of vaccine against the disease and were less infected (3.44%) than the others (5.17%). Age (p =0.000), level of education (p =0.013), occupation (p = 0.002), belief in the traditional healing of hepatitis B (p =0.000) and knowledge about the disease and its contamination roads (p=0.049) were associated with viral hepatitis B. CONCLUSION: There is a need of intensifying awareness, education, routine screening and vaccination of the population, especially in schools and university milieu to better counteract the infection with hepatitis B virus in our local Communities.

Public-Private Partnerships (PPPs) are defined as a collaborative approach in which the public and private sector share resources, responsibilities and risks to achieve common objectives and mutual benefits in a sustainable manner. PPPs are identified as a key solution to reinforce Veterinary Services. However only limited information is available on the scope, added value and enabling factors of PPPs in this sector. The aims of this study were to develop a typology of PPPs in the veterinary field and to identify key success factors and obstacles to their implementation. A structured questionnaire was sent to all 181 World Organisation for Animal Health (OIE) Member Countries and to 47 private contacts. 36 different variables characterizing PPP initiatives were collected. 97 examples of PPPs were retrieved from 76 countries. Dimensionality reduction techniques were combined with clustering and discrimination methods to establish a typology of PPPs and to derive a set of simple rules to classify new instances of PPPs. Three clusters were identified, separated according to two main variables: the type of private partners and the type of interaction. Cluster 1, transactional PPPs, represented the traditional understanding of PPPs by Veterinary Services, initiated and funded by the public sector, giving service delivery accreditation to mostly private veterinarians; cluster 2, collaborative PPPs, included partnerships between producer associations and public Veterinary Services, driven by trade interests; cluster 3, transformational PPPs, represented joint programs initiated and funded by private companies and initially driven by business development objectives. Specific success factors and key obstacles affecting the performances and sustainability of these initiatives were identified for each cluster. This study represents the first practical attempt to develop a meaningful typology of PPPs in the field of animal health and to identify fundamental obstacles currently inhibiting the development of PPPs, and suggests ways to support national Veterinary Services in overcoming these obstacles.

BACKGROUND:Tsetse (Glossina sensu stricto) are cyclical vectors of human and animal trypanosomoses, that are presently targeted by the Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC) coordinated by the African Union. In order to achieve effective control of tsetse, there is need to produce elaborate plans to guide intervention programmes. A model intended to aid in the planning of intervention programmes and assist a fuller understanding of tsetse distribution was applied, in a pilot study in the Masoka area, Mid-Zambezi valley in Zimbabwe, and targeting two savannah species, Glossina morsitans morsitans and Glossina pallidipes. METHODOLOGY/PRINCIPAL FINDINGS:The field study was conducted between March and December 2015 in 105 sites following a standardized grid sampling frame. Presence data were used to study habitat suitability of both species based on climatic and environmental data derived from MODIS and SPOT 5 satellite images. Factors influencing distribution were studied using an Ecological Niche Factor Analysis (ENFA) whilst habitat suitability was predicted using a Maximum Entropy (MaxEnt) model at a spatial resolution of 250 m. Area Under the Curve (AUC), an indicator of model performance, was 0.89 for G. m. morsitans and 0.96 for G. pallidipes. We then used the predicted suitable areas to calculate the probability that flies were really absent from the grid cells where they were not captured during the study based on a probability model using a risk threshold of 0.05. Apart from grid cells where G. m. morsitans and G. pallidipes were captured, there was a high probability of presence in an additional 128 km2 and 144 km2 respectively. CONCLUSIONS/SIGNIFICANCE:The modelling process promised to be useful in optimizing the outputs of presence/absence surveys, allowing the definition of tsetse infested areas with improved accuracy. The methodology proposed here can be extended to all the tsetse infested parts of Zimbabwe and may also be useful for other PATTEC national initiatives in other African countries.

L’apparition de l’influenza aviaire hautement pathogène (IAHP) H5N1 en 2003 a accentué la nécessité de disposer de systèmes de surveillance en santé animale efficaces pour éviter une pandémie grippale. Dans certains pays des mesures ad hoc ont été mises en place, soutenues par des bailleurs mais sans véritable ancrage sur le terrain ou auprès des institutions publiques chargées d’assurer une veille sanitaire. D’autres dispositifs, au contraire, ont permis de renforcer les structures déjà en place. L’objectif de cette étude a été de faire un état des lieux des dispositifs de surveillance de l’IAHP chez les volailles au Vietnam afin d’éva­luer la complémentarité des dispositifs nationaux (financés par le gouvernement vietnamien) et des programmes mis en place par les bailleurs internationaux. Les différents types de dispositifs de surveillance, d’études épidémiologique et de projets recherche sur l’IAHP au Vietnam ont été évalués dans l’ensemble complé­mentaires, assurant une couverture homogène du pays. Cependant les nouvelles politiques gouvernementales ont pour la plupart été décidées sans évaluation des actions antérieures en raison d’une insuffisance de données d’évaluation ou d’impact des projets mis en œuvre. Un dysfonctionnement du système de sur­veillance passive, avec un retour limité des résultats et des recommandations aux agents de terrain, a également été constaté. La mise en place de dispositifs de surveillance active efficients en complément de la surveillance passive s’avère donc essentielle dans la gestion du risque de l’IAHP au Vietnam.

The maintenance mechanisms of ebolaviruses in African forest ecosystems are still unknown, but indirect evidences point at the involvement of some bat species. Despite intense research, the main bat-maintenance hypothesis has not been confirmed yet. The alternative hypotheses of a non-bat maintenance host or a maintenance community including, or not, several bat and other species, deserves more investigation. However, African forest ecosystems host a large biodiversity and abound in potential maintenance hosts. How does one puzzle out? Since recent studies have revealed that several bat species have been exposed to ebolaviruses, the common denominator to these hypotheses is that within the epidemiological cycle, some bats species must be exposed to the viruses and infected by these potential alternative hosts. Under this constraint, and given the peculiar ecology of bats (roosting behaviour, habitat utilisation, and flight mode), we review the hosts and transmission pathways that can lead to bat exposure and infection to ebolaviruses. In contrast to the capacity of bats to transmit ebolaviruses and other pathogens to many hosts, our results indicate that only a limited number of hosts and pathways can lead to the transmission of ebolaviruses to bats, and that the alternative maintenance host, if it exists, must be amongst them. A list of these pathways is provided, along with protocols to prioritise and investigate these alternative hypotheses. In conclusion, taking into account the ecology of bats and their known involvement in ebolaviruses ecology drastically reduces the list of potential alternative maintenance hosts for ebolaviruses. Understanding the natural history of ebolaviruses is a health priority, and investigating these alternative hypotheses could complete the current effort focused on the role of bats.

African swine fever is a highly contagious disease of pigs in Africa. Although its persistence in Senegal may be caused by asymptomatic carriers involved in the domestic transmission cycle, we demonstrated that the soft tick Ornithodoros sonrai can be naturally infected with the causative agent.

We investigated the influence of a mass poultry vaccination campaign on passive surveillance of highly pathogenic avian influenza subtype (H5N1) outbreaks among poultry in Egypt. Passive reporting dropped during the campaign, although probability of infection remained unchanged. Future poultry vaccination campaigns should consider this negative impact on reporting for adapting surveillance strategies.

Une enquête destinée à déterminer les caractères distinctifs entre élevages atteints et élevages indemnes de dermatophilose a été menée dans 93 élevages bovins de Martinique et 120 élevages de Guadeloupe et Saint-Martin. Près de la moitié de ces élevages étaient ou avaient été infectés. La morbidité dans les exploitations concernées par la maladie est de 33 p. 100 en Martinique et de 29 p. 100 en Guadeloupe, les mortalités annuelles étant respectivement de 15 et 5 p. 100. On n'observe pas de différences de fréquence de la maladie en fonction de la saison et de la zone géographique. La présence de la tique Amblyomma variegatum, en revanche, est déterminante dans la situation de la Martinique où les animaux de toutes les races sont sensibles à la maladie. Dans ce cas, 63 p. 100 des élevages infestés sont atteints, contre 2,5 p. 100 pour les élevages encore épargnés par la tique. En Guadeloupe où le zébu Créole, du fait d'une sélection naturelle, est hautement résistant, seuls 27 p. 100 des élevages de l'enquête qui sont infestés connaissent la dermatophilose. Le détiquage régulier dans les deux îles a une action bénéfique sur la fréquence de la maladie. L'enquête révèle une typologie sous-jacente des élevages et permet de les classer en fonction de leur comportement face à la maladie.

Flow-through time resolved analysis (FT-TRA) involves subjecting small mineral samples (< 10 mg) inserted in a miniature flow-through cell (50 μL) to controlled flows of eluent analyzed on-line by ICP-MS. In this study, FT-TRA is used to empirically determine the dissolution regimes for the two well-studied minerals forsterite and calcite, representing minerals with relatively slow and fast dissolution kinetics. A proportional increase in steady-state effluent [Mg, Si] concentrations with increasing flow-through cell eluent residence times confirms a dominantly surface-controlled dissolution regime for a powdered forsterite sample at pH 2.3, implying that transport limitations are negligible. In contrast, the relationship between flow rates and dissolution rates for single grain calcite samples at pH 2.3-4 reveals that transport limitations affect the rate of calcite dissolution. To provide a quantitative and process-based assessment of the effect of diffusive transport limitations, simulations of the calcite experiments were performed with a high resolution, pore-scale model that considers the geometry of the calcite grain and the FT-TRA flow-through reactor. The pore-scale model reproduces the observed effluent [Ca] concentrations for all experimental conditions using a single set of surface kinetic parameters, by accounting for the formation of a diffusive boundary layer (DBL) that varies in thickness as a function of flow rates. These results demonstrate that combining FT-TRA with pore-scale modeling makes it possible to obtain unprecedented insights not achievable by either method separately, including quantification of DBL thicknesses and the determination of transport controls as a function of pH, flow velocity and residence times.

Une enquête portant sur 276 animaux atteints de dermatophilose en Guadeloupe et en Martinique a permis de montrer que 90 % des malades ont des lésions hautes, 65 % des lésions basses et 30 % des lésions atypiques. Les lésions hautes semblent constituer la principale localisation initiale, les formes basses et atypiques étant celles qui évoluent le plus rapidement et qui sont le plus souvent mortelles. Aucun des facteurs analysés (sites préférentiels d'attachement des tiques, forte insolation, abondance d'épineux ou sol humide) n'explique la localisation des lésions. L'analyse de 135 sérums a montré qu'il existe une relation assez étroite entre la présence des lésions et la présence d'anticorps dans le sérum et une relation proportionnelle entre le titre du sérum et la gravité des lésions. Certaines réactions sérologiques atypiques sont en faveur de l'existence d'animaux porteurs asymptomatiques de germes, d'autres permettent de suspecter l'existence de phénomènes de déficience immunitaire.

Une enquête portant sur 573 bovins élevés en milieu infecté a été menée dans les Antilles françaises afin de repérer les facteurs individuels favorisant l’apparition et l’évolution de la maladie. La réceptivité des animaux est très différente en Guadeloupe et en Martinique. La race n’explique le phénomène pathologique que si l’on prend en compte le passé épidémiologique des animaux et en particulier l’ancienneté de la coévolution avec la tique A. variegatum. Le bovin Créole de Guadeloupe est en contact avec la tique depuis toujours et seulement 5 % des animaux examinés sont atteints alors que le bovin Créole de Martinique, exposé depuis peu à l’infestation, est extrêmement réceptif puisque 82 % des animaux échantillonnés sont atteints. Dans les deux îles, l’incidence de la maladie chez les animaux exotiques, récemment importés, est comprise entre 38 et 84 %. Même des infestations faibles par Amblyomma induisent la dermatophilose sur le bétail très sensible de Martinique alors qu’il y a en Guadeloupe une relation proportionnelle entre le niveau d’infestation et la probabilité d’infection. En Guadeloupe, la race et l’abondance des tiques sont les facteurs les plus explicatifs alors qu’en Martinique, s’il y a des tiques, quelle que soit leur abondance et quelle que soit la race, la dermatophilose revêt une forte incidence.