Cost-benefit analysis of mass vaccination campaign against H5N1 in small scale production systems in Vietnam. Part I: Economical results in Long An province

Highly Pathogenic Avian Influenza (HPAI) caused by H5N1 virus has become endemic in some developing countries and millions of birds have been culled with large economical and sociological impacts. Since the end of the first vaccination campaign in Vietnam limited outbreaks in non-vaccinated domestic poultry have been reported. However, the virus is still circulating as confirmed by routine surveillance programs. Vaccination is a useful tool to be used to eradicate the disease, but the cost-benefit impact of different strategy needs first to be addressed at local level, where implementation is decided. The aim of this study was to evaluate the cost-benefit impact of Vietnam mass vaccination program at local level. This poster presents the first step in the cost-benefit analysis: the partial economical analysis of the vaccination within Vietnam provinces. Only the results in Long An province (South) are presented here

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

Rift Valley fever (RVF) is a severe mosquito-borne disease affecting humans and domestic ruminants. RVF virus has been reported in most African countries, as well as in the Arabic Peninsula. This paper reviews the different types of socio-eco- nomic impact induced by RVF disease and the attempts to evaluate them. Of the 52 papers selected for this review, 13 types of socio-economic impact were identi- fied according to the sector impacted, the level and temporal scale of the impact. RVF has a dramatic impact on producers and livestock industries, affecting public and animal health, food security and the livelihood of the pastoralist communities. RVF also has an impact on international trade and other agro-industries. The risk of introducing RVF into disease-free countries via the importation of an infected animal or mosquito is real, and the consequent restriction of access to export mar- kets may induce dramatic economic consequences for national and local econo- mies. Despite the important threat of RVF, few studies have been conducted to assess the socio-economic impact of the disease. The 17 studies identified for quantitative analysis in this review relied only on partial cost analysis, with limited reference to mid- and long-term impact, public health or risk mitigation mea- sures. However, the estimated impacts were high (ranging from $5 to$470 mil- lion USD losses). To reduce the impact of RVF, early detection and rapid response should be implemented. Comprehensive disease impact studies are required to provide decision-makers with science-based information on the best intervention measure to implement ensuring efficient resource allocation. Through the analysis of RVF socio-economic impact, this scoping study proposes insights into the mechanisms underpinning its often-underestimated importance. This study high- lights the need for comparative socio-economic studies to help decision-makers with their choices related to RVF disease management

The RISKSUR EVA Tool (Survtool): a tool for the integrated evaluation of animal health surveillance systems

Information about infectious diseases at the global level relies on effective, efficient and sustainable national and international surveillance systems. Surveillance systems need to be regularly evaluated to ensure their effectiveness, the quality of the data and information provided, as well as to be able to allocate resources efficiently. Currently available frameworks for evaluation of surveillance systems in animal or human health often treat technical, process and socio-economic aspects separately instead of integrating them. The surveillance evaluation (EVA) tool, a support tool for the evaluation of animal health surveillance systems, was developed to provide guidance for integrated evaluation of animal health surveillance including economic evaluation. The tool was developed by international experts in surveillance and evaluation in an iterative process of development, testing and revision; taking into account existing frameworks and guidance, scientific literature and expert opinion elicitation. The EVA tool encompasses a web interface for users to develop an evaluation plan, a Wiki classroom to provide theoretical information on all required concepts and a generic evaluation work plan to facilitate implementation and reporting of outputs to decision makers. The tool was used to plan and conduct epidemiological and economic evaluations of surveillance for classical and African swine fever, bovine virus diarrhoea, avian influenza, and Salmonella Dublin in five European countries. These practical applications highlighted the importance of a comprehensive evaluation approach to improve the quality of the evaluation outputs (economic evaluation; multiple attributes assessment) and demonstrated the usefulness of the guidance provided by the EVA tool. At the same time they showed that comprehensive evaluations might be constrained by practical issues (e.g. confidentiality concerns, data availability) and resource scarcity. In the long term, the EVA tool is expected to increase professional evaluation capacity and help optimising health surveillance system efficiency and resource allocation for both public and private actors of the surveillance systems

On Technological and Immunological Benefits of Multivalent Single-Injection Microsphere Vaccines

Purpose. With the aim of developing multivalent vaccines for single-injection, we examined the feasibility of combining antigens in biodegradable microspheres. Such vaccines are expected to improve vaccination coverage by reducing the number of vaccination sessions required to generate immunity. Methods. Mono- and multivalent vaccines of Haemophilus influenzae type b (Hib) conjugate, diphtheria toxoid (DT), tetanus toxoid (TT), and pertussis toxin (PT) in poly (lactic acid) and poly(lactic-coglycolic acid) microspheres were prepared by spray drying, and the influence of coencapsulated antigens and excipients on antigen loading, release, and stability was examined. Two tetravalent formulations were tested in guinea pigs. Results. Monovalent Hib and PT vaccines showed loading efficiencies of 10% (Hib) and 30% (PT) in both polymers. The loading efficiencies increased upon addition of trehalose and, even more, when the antigens were coencapsulated in di- and trivalent combinations. Highest loading efficiencies (>80%) were achieved with trivalent formulations (DT + PT + Hib) that also contained coencapsulated albumin. The percentage of antigen released during 24 h of incubation was typically 10-40% and decreased as loading efficiency increased. Enzyme-linked immunosorbent assay (ELISA) data revealed that TT, DT, and PT remained antigenic throughout the encapsulation and subsequent release processes. Finally, all antigens maintained their immunogenicity, since strong and sustained antibody responses were elicited after a single injection of tetravalent microsphere vaccines (DT + TT + PT + Hib) in guinea pigs. Conclusions. This study reveals technologic benefit as well as an immunological potential of multivalent single-injection microsphere vaccines. The results support our hypothesis that coencapsulation of several antigens may intrinsically improve entrapment of antigenic and immunogenic antigen probably by virtue of increased protein concentration during microencapsulation leading to mutual stabilization of the component

Relation between the poultry production systems and the Highly Pathogenic Avian Influenza (HPAI) in Vietnam

In 2003, the poultry population was about 254.6 millions heads. The poultry herd is mainly concentrated in the Red River Delta (RRD) and in the Mekong Delta with about 50% of poultry population. The Highly Pathogenic Avian Influenza caused by H5N1 virus was removed in almost of provinces in Vietnam from 2004 until now but millions of birds were culled to reach this situation and it had large economical and sociological impacts. A question emerge: how can we limit this epidemic? A research on the relation between poultry production systems and the HPAI had been carried out in two provinces: Ha Tay (RRD) and Long An (Mekong Delta) from March to August 2007. The results showed that there are three principal poultry production systems which are commercial poultry production systems with good breeding facilities (system 1); commercial poultry production systems without good breeding facilities (system 2), and small scale poultry production system (system 3). The number of birds reared in the commercial systems was more important than that of the small system, conversely the number of species rising in the system 2 and 3 was more important than in the system 1. The proportion of households having poultry herd with HPAI in the period of 2003-2005 in the system 2 and 3 were more important than that of the system 1 (21-59% compare with 33-36%). The study had showed that all poultry belonging to the system 1 were vaccinated; when the proportion of vaccinated animals were about 87-90% for the system 2, and 58% for the system 3

Modelling influenza A H5N1 vaccination strategy scenarios in the household poultry sector in Egypt

Highly pathogenic avian influenza (AI) due to H5N1 virus was first reported in Egypt in February 2006; since then, the government has allowed avian influenza vaccination in poultry. The present study evaluated the impact of AI vaccination in terms of cumulative annual flock immunity (CAFI): the percentage of bird × weeks protected by immunity. This evaluation took account of the combined effects of vaccination coverage, vaccine efficacy (VE), and different characteristics of household poultry production on the effectiveness of the adopted vaccination strategy (VS), and provided alternative options for improvement. The evaluation used a population and vaccination model that calculates the CAFI. Participatory approaches were employed in 21 villages to develop the vaccination and flock parameters required for the model. The adopted VS were compared in the model with three alternative VS scenarios in terms of the CAFI. Vaccination coverage varied among villages but was generally low (between 1 and 48 %; median 14 %). Under the adopted VS, the CAFI predicted for the villages ranged from 2 to 31 %. It was concluded that despite the enormous effort put into rural household poultry AI vaccination by the Egyptian government, village CAFI is unlikely to be maintained at the levels required to significantly reduce the virus load and restrict transmission. In HPAI-endemic countries that consider AI vaccination as one of the disease control options, the high cost of mass AI vaccination campaigns and their achievable benefits must be compared with other available control measures, which may include targeted vaccination. Achievable vaccination coverage, VE and the different characteristics of commercial and household (village) poultry production are key parameters determining the feasibility and cost-effectiveness of different AI vaccination strategies

Application of discrete choice experiment to assess farmers’ willingness to report swine diseases in the Red River Delta region, Vietnam

peer reviewedA discrete choice experiment (DCE) is carried out to value socio-economic factors influencing the farmer’s decision to report swine diseases and to assess the willingness of farmers to report swine diseases. Data were collected between March and July 2015 in two provinces in the Red River Delta, Northern Vietnam, from 196 pig producers by face-to face interview. A conditional logit model is used to measure the relative importance of the socio-economic factors and calculate the expected probability of disease reporting under changes of levels of these factors. Results of the study indicated that the likelihood of compensation and the type of culling implemented (all or only unrecovered pigs) are the two most important factors influencing farmer reporting. Compensation level, movement restriction and delay in compensation payment also have significant impacts on farmer’s decision to report animal disease but they are not as important as the above factors. Three different scenarios including changes in six different factors (attributes) are tested to predict probability of animal disease reporting. Under the current situation (uncertainty of being compensated), only 4% of the farmers would report swine disease outbreak to the official surveillance system if the culling policy involves all pigs in affected farms. This number is increased to 26% if culling in affected farms is restricted to unrecovered pigs only. Ensuring certainty of compensation increases reporting probability by up to 50% and 90% if all or only unrecovered pigs are destroyed, respectively. The results of this study are important for improving the performance and sustainability of swine disease surveillance system in Vietnam