scholarly journals Robustness of local control strategies under modelling uncertainties: the 2004 avian influenza H5N1 outbreak in Thailand

2018 ◽  
Author(s):  
Renata Retkute ◽  
Chris P. Jewell ◽  
Thomas P. Van Boeckel ◽  
Geli Zhang ◽  
Xiangming Xiao ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Control Strategies ◽  
Model Fitting ◽  
Significant Risk ◽  
Disease Outbreaks ◽  
Control Policy ◽  
Poultry Industry ◽  
Epidemic Size ◽  
Hpai H5n1 ◽  
The Impact

AbstractThe Highly Pathogenic Avian Influenza (HPAI) subtype H5N1 virus persists in many countries and has been circulating in poultry, wild birds. In addition, the virus has emerged in other species and frequent zoonotic spillover events indicate that there remains a significant risk to human health. It is crucial to understand the dynamics of the disease in the poultry industry to develop a more comprehensive knowledge of the risks of transmission and to establish a better distribution of resources when implementing control. In this paper, we develop a set of mathematical models that simulate the spread of HPAI H5N1 in the poultry industry in Thailand, utilising data from the 2004 epidemic. The model that incorporates the intensity of duck farming when assessing transmision risk provides the best fit to the spatiotemporal characteristics of the observed outbreak, implying that intensive duck farming drives transmission of HPAI in Thailand. We also extend our models using a sequential model fitting approach to explore the ability of the models to be used in “real time” during novel disease outbreaks. We conclude that, whilst predictions of epidemic size are estimated poorly in the early stages of disease outbreaks, the model accurately predicts the preferred control policy that should be deployed to minimise the impact of the disease.

scholarly journals Threshold Effects of Infectious Disease Outbreaks on Livestock Prices: Cases of African Swine Fever and Avian Influenza in South Korea

2021 ◽  
Vol 11 (11) ◽  
pp. 5114
Author(s):  
Hyung-Chul Rah ◽  
Hyeon-Woong Kim ◽  
Aziz Nasridinov ◽  
Wan-Sup Cho ◽  
Seo-Hwa Choi ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Infectious Diseases ◽  
Disease Outbreaks ◽  
African Swine Fever ◽  
Threshold Effect ◽  
Impact Response ◽  
Threshold Effects ◽  
Infectious Disease Outbreaks ◽  
Retail Prices ◽  
The Impact

In this paper we demonstrate the threshold effects of infectious diseases on livestock prices. Daily retail prices of pork and chicken were used as structured data; news and SNS mentions of African Swine Fever (ASF) and Avian Influenza (AI) were used as unstructured data. Models were tested for the threshold effects of disease-related news and SNS frequencies, specifically those related to ASF and AI, on the retail prices of pork and chicken, respectively. The effects were found to exist, and the values of ASF-related news on pork prices were estimated to be −9 and 8, indicating that the threshold autoregressive (TAR) model can be divided into three regimes. The coefficients of the ASF-related SNS frequencies on pork prices were 1.1666, 0.2663 and −0.1035 for regimes 1, 2 and 3, respectively, suggesting that pork prices increased by 1.1666 Korean won in regime 1 when ASF-related SNS frequencies increased. To promote pork consumption by SNS posts, the required SNS frequencies were estimated to have impacts as great as one standard deviation in the pork price. These values were 247.057, 1309.158 and 2817.266 for regimes 1, 2 and 3, respectively. The impact response periods for pork prices were estimated to last 48, 6, and 8 days for regimes 1, 2 and 3, respectively. When the prediction accuracies of the TAR and autoregressive (AR) models with regard to pork prices were compared for the root mean square error, the prediction accuracy of the TAR model was found to be slightly better than that of the AR. When the threshold effect of AI-related news on chicken prices was tested, a linear relationship appeared without a threshold effect. These findings suggest that when infectious diseases such as ASF occur for the first time, the impact on livestock prices is significant, as indicated by the threshold effect and the long impact response period. Our findings also suggest that the impact on livestock prices is not remarkable when infectious diseases occur multiple times, as in the case of AI. To date, this study is the first to suggest the use of SNS to promote meat consumption.

scholarly journals Applications of percolation theory to fungal spread with synergy

2011 ◽  
Vol 9 (70) ◽  
pp. 949-956 ◽  
Author(s):  
Jonathan J. Ludlam ◽  
Gavin J. Gibson ◽  
Wilfred Otten ◽  
Christopher A. Gilligan
Keyword(s):  
Control Strategies ◽  
Model Fitting ◽  
Structured Populations ◽  
Synergistic Interactions ◽  
Non Invasive ◽  
History Of ◽  
Disease Spreading ◽  
Strict Requirement ◽  
Using Data ◽  
The Impact

There is increasing interest in the use of the percolation paradigm to analyse and predict the progress of disease spreading in spatially structured populations of animals and plants. The wider utility of the approach has been limited, however, by several restrictive assumptions, foremost of which is a strict requirement for simple nearest-neighbour transmission, in which the disease history of an individual is influenced only by that of its neighbours. In a recent paper, the percolation paradigm has been generalized to incorporate synergistic interactions in host infectivity and susceptibility, and the impact of these interactions on the invasive dynamics of an epidemic has been demonstrated. In the current paper, we elicit evidence that such synergistic interactions may underlie transmission dynamics in real-world systems by first formulating a model for the spread of a ubiquitous parasitic and saprotrophic fungus through replicated populations of nutrient sites and subsequently fitting and testing the model using data from experimental microcosms. Using Bayesian computational methods for model fitting, we demonstrate that synergistic interactions are necessary to explain the dynamics observed in the replicate experiments. The broader implications of this work in identifying disease-control strategies that deflect epidemics from invasive to non-invasive regimes are discussed.

Animal and Human Health Implications of Avian Influenza Infections

2007 ◽  
Vol 27 (6) ◽  
pp. 359-372 ◽  
Author(s):  
Ilaria Capua ◽  
Dennis J. Alexander
Keyword(s):  
Avian Influenza ◽  
Human Health ◽  
H5n1 Virus ◽  
Animal Health ◽  
Control Measures ◽  
Health Issues ◽  
Human Beings ◽  
Highly Pathogenic ◽  
Hpai H5n1 ◽  
The Impact

Avian influenza (AI) is a listed disease of the World Organisation for Animal Health (OIE) that has become a disease of great importance both for animal and human health. Until recent times, AI was considered a disease of birds with zoonotic implications of limited significance. The emergence and spread of the Asian lineage highly pathogenic AI (HPAI) H5N1 virus has dramatically changed this perspective; not only has it been responsible of the death or culling of millions of birds, but this virus has also been able to infect a variety of non-avian hosts including human beings. The implications of such a panzootic reflect themselves in animal health issues, notably in the reduction of a protein source for developing countries and in the management of the pandemic potential. Retrospective studies have shown that avian progenitors play an important role in the generation of pandemic viruses for humans, and therefore these infections in the avian reservoir should be subjected to control measures aiming at eradication of the Asian H5N1 virus from all sectors rather than just eliminating or reducing the impact of the disease in poultry.

scholarly journals Impact of the implementation of rest days in live bird markets on the dynamics of H5N1 highly pathogenic avian influenza

2010 ◽  
Vol 8 (61) ◽  
pp. 1079-1089 ◽  
Author(s):  
G. Fournié ◽  
F. J. Guitian ◽  
P. Mangtani ◽  
A. C. Ghani
Keyword(s):  
Avian Influenza ◽  
Highly Pathogenic Avian Influenza ◽  
Control Strategies ◽  
Effective Means ◽  
Transmission Model ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Live Bird Markets ◽  
Hpai H5n1 ◽  
Live Bird

Live bird markets (LBMs) act as a network ‘hub’ and potential reservoir of infection for domestic poultry. They may therefore be responsible for sustaining H5N1 highly pathogenic avian influenza (HPAI) virus circulation within the poultry sector, and thus a suitable target for implementing control strategies. We developed a stochastic transmission model to understand how market functioning impacts on the transmission dynamics. We then investigated the potential for rest days—periods during which markets are emptied and disinfected—to modulate the dynamics of H5N1 HPAI within the poultry sector using a stochastic meta-population model. Our results suggest that under plausible parameter scenarios, HPAI H5N1 could be sustained silently within LBMs with the time spent by poultry in markets and the frequency of introduction of new susceptible birds' dominant factors determining sustained silent spread. Compared with interventions applied in farms (i.e. stamping out, vaccination), our model shows that frequent rest days are an effective means to reduce HPAI transmission. Furthermore, our model predicts that full market closure would be only slightly more effective than rest days to reduce transmission. Strategies applied within markets could thus help to control transmission of the disease.

scholarly journals Assessing the airborne survival of bacteria in populations of aerosol droplets with a novel technology

2019 ◽  
Vol 16 (150) ◽  
pp. 20180779 ◽  
Author(s):  
Mara Otero Fernandez ◽  
Richard J. Thomas ◽  
Natalie J. Garton ◽  
Andrew Hudson ◽  
Allen Haddrell ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Control Strategies ◽  
Disease Outbreaks ◽  
New Approach ◽  
Novel Technology ◽  
Time Period ◽  
Colony Forming Units ◽  
Droplet On Demand ◽  
The Impact

The airborne transmission of infection relies on the ability of pathogens to survive aerosol transport as they transit between hosts. Understanding the parameters that determine the survival of airborne microorganisms is critical to mitigating the impact of disease outbreaks. Conventional techniques for investigating bioaerosol longevity in vitro have systemic limitations that prevent the accurate representation of conditions that these particles would experience in the natural environment. Here, we report a new approach that enables the robust study of bioaerosol survival as a function of relevant environmental conditions. The methodology uses droplet-on-demand technology for the generation of bioaerosol droplets (1 to greater than 100 per trial) with tailored chemical and biological composition. These arrays of droplets are captured in an electrodynamic trap and levitated within a controlled environmental chamber. Droplets are then deposited on a substrate after a desired levitation period (less than 5 s to greater than 24 h). The response of bacteria to aerosolization can subsequently be determined by counting colony forming units, 24 h after deposition. In a first study, droplets formed from a suspension of Escherichia coli MRE162 cells (10 8 ml −1 ) with initial radii of 27.8 ± 0.08 µm were created and levitated for extended periods of time at 30% relative humidity. The time-dependence of the survival rate was measured over a time period extending to 1 h. We demonstrate that this approach can enable direct studies at the interface between aerobiology, atmospheric chemistry and aerosol physics to identify the factors that may affect the survival of airborne pathogens with the aim of developing infection control strategies for public health and biodefence applications.

An overview of the epidemic of highly pathogenic H5N1 avian influenza virus in Egypt: epidemiology and control challenges

2011 ◽  
Vol 139 (5) ◽  
pp. 647-657 ◽  
Author(s):  
E. M. ABDELWHAB ◽  
H. M. HAFEZ
Keyword(s):  
Public Health ◽  
Avian Influenza ◽  
H5n1 Virus ◽  
Nile Delta ◽  
Poultry Industry ◽  
Potential Threat ◽  
Highly Pathogenic ◽  
H5n1 Avian Influenza Virus ◽  
Hpai H5n1 ◽  
And Control

SUMMARYEmergence of the highly pathogenic avian influenza (HPAI) H5N1 virus in Egypt in mid-February 2006 caused significant losses for the poultry industry and constituted a potential threat to public health. Since late 2007, there has been increasing evidence that stable lineages of H5N1 viruses are being established in chickens and humans in Egypt. The virus has been detected in wild, feral and zoo birds and recently was found in donkeys and pigs. Most of the outbreaks in poultry and humans occurred in the highly populated Nile delta. The temporal pattern of the virus has changed since 2009 with outbreaks now occurring in the warmer months of the year. Challenges to control of endemic disease in Egypt are discussed. For the foreseeable future, unless a global collaboration exists, HPAI H5N1 virus in Egypt will continue to compromise the poultry industry, endanger public health and pose a serious pandemic threat.

scholarly journals Maintenance of Fish Health in Aquaculture: Review of Epidemiological Approaches for Prevention and Control of Infectious Disease of Fish

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ayalew Assefa ◽  
Fufa Abunna
Keyword(s):  
Infectious Disease ◽  
Traffic Control ◽  
Prevention And Control ◽  
Control Strategies ◽  
Disease Outbreaks ◽  
Effective Prevention ◽  
Disease Case ◽  
And Control ◽  
Water Treatments ◽  
The Impact

Aquaculture is rapidly growing part of agriculture worldwide. It makes up around 44 percent of total fish production globally. This increased growth of production is achieved despite facing many challenges in the aquaculture environment. Among production limiting challenges, the infectious disease takes the lion share by causing multibillion-dollar loss annually. To reduce the impact of the fish disease, it is necessary to address health constraints based on scientifically proven and recommended ways. This review aims at pointing out some of the best approaches to prevention and control of infectious disease in aquaculture. Among the effective prevention and control strategies, vaccination is one of the key practices. Types of vaccines for use in fish include killed vaccines, attenuated vaccines, DNA vaccines, recombinant technology vaccines, and synthetic peptide vaccines. Administration techniques of vaccines in fish include oral, injection, or immersion methods. Antibiotics are also in use in aquaculture despite their side effects in the development of drug resistance by microorganisms. Biological and chemical disease control strategies such as using probiotics, prebiotics, and medicinal plants are widely in use. Biosecurity measures in aquaculture can keep the safety of a facility from certain disease-causing agents that are absent in particular system. Farm-level biosecurity measures include strict quarantine measures, egg disinfection, traffic control, water treatments, clean feed, and disposal of mortalities. In conclusion, rather than trying to treat every disease case, it advisable to follow a preventive approach before the event of any disease outbreaks.

POLISH POULTRY INDUSTRY IN THE FACE OF AVIAN INFLUENZA

2017 ◽  
Vol XIX (2) ◽  
pp. 256-262
Author(s):  
Mirosława Tereszczuk
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Large Scale ◽  
Point Of View ◽  
Poultry Meat ◽  
Positive Trend ◽  
Poultry Industry ◽  
Eu Countries ◽  
The Impact

The aim of the study is to evaluate the impact of the HPAI/H5N8 avian influenza virus on the functioning and development of the poultry industry in Poland. The virus appeared in Poland at the turn of 2016/2017 (after a 10-year break) and was present in our country (12 voivodships) for 3.5 months, ie from 4 December 2016 to 16 March 2017. On a large scale this virus has occurred across Europe. The first cases of domestic and wild poultry were found at the end of October 2016. By mid-March 2017, over 2.3 thousand. Outbreaks of this disease in 23 EU countries, including over 1,000 outbreaks, have been reported in poultry. The virus was found both in poultry kept in the poultry system and in farmyard. The appearance of the avian influenza virus in Poland was a negative factor affecting the poultry industry, resulting in production losses and export restrictions introduced by non-EU countries. There was a slowdown in the growth rate of the poultry sector in Poland and a decrease in exports of live poultry. However, this was a transitional phenomenon. Despite the threat, the consumption of poultry meat in Poland is growing steadily. This is a positive trend, from the point of view of the commercial interests of our country, which has become the largest producer of poultry meat in the EU.

scholarly journals The securitisation of avian influenza: international discourses and domestic politics in Asia

2010 ◽  
Vol 37 (1) ◽  
pp. 141-166 ◽  
Author(s):  
MELISSA G. CURLEY ◽  
JONATHAN HERINGTON
Keyword(s):  
Avian Influenza ◽  
Domestic Politics ◽  
Disease Outbreaks ◽  
World Health ◽  
Security Threat ◽  
Security Issue ◽  
Security Issues ◽  
Infectious Disease Outbreaks ◽  
Health Organization ◽  
The Impact

AbstractInfectious disease outbreaks primarily affect communities of individuals with little reference to the political borders which contain them; yet, the state is still the primary provider of public health capacity. This duality has profound effects for the way disease is framed as a security issue, and how international organisations, such as the World Health Organization, assist affected countries. The article seeks to explore the role that domestic political relationships play in mediating the treatment of diseases as security issues. Drawing upon an analysis of the securitisation of avian influenza in Vietnam and Indonesia, the article discusses the effect that legitimacy, competing referents and audiences have on the external and internal policy reactions of states to infectious diseases, specifically in their interpretation of disease as a security threat. In doing so, we extend upon existing debates on the Copenhagen School's securitisation framework, particularly on the impact of domestic political structures on securitisation processes in non-Western, non-democratic and transitional states.

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