Economic Analysis of Vaccination Strategies for PRRS Control

Porcine reproductive and respiratory syndrome virus (PRRSv) is a swine-specific pathogen that causes significant increases in production costs. When a breeding herd becomes infected, in an attempt to hasten control and elimination of PRRSv, some veterinarians have adopted a strategy called load-close-expose which consists of interrupting replacement pig introductions into the herd for several weeks (herd closure) and exposing the whole herd to a replicating PRRSv to boost herd immunity. Either modified-live virus (MLV) vaccine or live field-virus inoculation (FVI) is used. This study consisted of partial budget analyses to compare MLV to FVI as the exposure method of load-close-expose program to control and eliminate PRRSv from infected breeding herds, and secondly to estimate benefit / cost of vaccinating sow herds preventatively. Under the assumptions used in this study, MLV held economic advantage over FVI. However, sensitivity analysis revealed that decreasing margin over variable costs below $ 47.32, or increasing PRRSv-attributed cost above $18.89 or achieving time-to-stability before 25 weeks resulted in advantage of FVI over MLV. Preventive vaccination of sow herds was beneficial when the frequency of PRRSv infection was at least every 2.1 years. The economics of preventative vaccination was minimally affected by cost attributed to field-type PRRSv infection on growing pigs or by the breeding herd productivity level. The models developed and described in this paper provide valuable tools to assist veterinarians in their efforts to control PRRSv.     

Pastoral Herding Strategies and Governmental Management Objectives: Predation Compensation as a Risk Buffering Strategy in the Saami Reindeer Husbandry

Previously it has been found that an important risk buffering strategy in the Saami reindeer husbandry in Norway is the accumulation of large herds of reindeer as this increases long-term household viability. Nevertheless, few studies have investigated how official policies, such as economic compensation for livestock losses, can influence pastoral strategies. This study investigated the effect of received predation compensation on individual husbandry units’ future herd size. The main finding in this study is that predation compensation had a positive effect on husbandry units’ future herd size. The effect of predation compensation, however, was nonlinear in some years, indicating that predation compensation had a positive effect on future herd size only up to a certain threshold whereby adding additional predation compensation had little effect on future herd size. More importantly, the effect of predation compensation was positive after controlling for reindeer density, indicating that for a given reindeer density husbandry units receiving more predation compensation performed better (measured as the size of future herds) compared to husbandry units receiving less compensation.     

The Economic Case for a Pandemic Fund

The rapid urban spread of Ebola virus in West Africa in 2014 and consequent breakdown of control measures led to a significant economic impact as well as the burden on public health and wellbeing. The US government appropriated $5.4 Billion for FY2015 and WHO proposed a $100 Million emergency fund largely to curtail the threat of future outbreaks. Using epidemiological analyses and economic modeling, we propose that the best use of these and similar funds would be to serve as global insurance against the continued threat of emerging infectious diseases. An effective strategy would involve the initial investment in strengthening mobile and adaptable capacity to deal with the threat and reality of disease emergence, coupled with repeated investment to maintain what is effectively a ‘national guard’ for pandemic prevention and response. This investment would create a capital stock that could also provide access to safe treatment during and between crises in developing countries, lowering risk to developed countries.     

Economic impact of clinical mastitis in a dairy herd assessed by stochastic simulation using different methods to model yield losses

The main aim of the present study was to examine the economic consequences of a reduction in the incidence of clinical mastitis (CM) at herd level under current Swedish farming conditions. A second objective was to ask whether the estimated cost of CM alters depending upon whether the model reflects the fact that in different stages of lactation, CM gives rise to different yield-loss patterns or postulates just one type of yield-loss pattern irrespective of when, during lactation, CM occurs. A dynamic and stochastic simulation model, SimHerd, was used to study the effects of CM in a herd with 150 cows (9000 kg of energy-corrected milk per cow-year). Four herd types, defined by production level and reproductive performance, were modelled to investigate possible interactions between herd type and response to a reduction in the risk of CM. Technical and economic results, given the initial incidence of CM (25.6 per 100 cow-years), were studied together with the consequences of reducing the initial risk of CM by 50% and 90% throughout lactation and the consequences of reducing the initial risk by 50% and 90% before peak yield. A conventional way of modelling yield losses - i.e. one employing a single yield-loss pattern irrespective of when, during the lactation period, the cow develops CM - was compared with a new modelling strategy in which CM was assumed to affect production differently depending on its lactational timing. The effect of the choice of reference level when estimating yield losses was investigated by comparing the results obtained using the potential yield of mastitic cows, had they not developed CM, with those obtained using the yield of non-mastitic cows. The yearly maximum avoidable cost of CM at herd level was estimated at €14 504, corresponding to 6.9% of the net return given the initial incidence of CM. Expressed per cow-year, the maximum avoidable cost was €97. The cost per case of CM was estimated at €428. Herd types all responded in a similar manner to the reduced relative risk of CM. There were no major differences in the results obtained using the new and the conventional modelling strategy, with the exception of the cost per case of CM. Similarities between the results obtained using the two methods were particularly evident when the mastitic cows' own yield level, had they not developed CM, was used as the reference for production in healthy cows when yield losses were estimated. It was concluded that the conventional way of modelling yield losses is adequate and should, for the foreseeable future, be used in decision support systems.     

Correspondence

The economic cost of the acquired immunodeficiency syndrome (AIDS) in San Diego County, California, is forecast to increase from $103 million in 1986 to between $502 and $743 million in 1991, rising at a minimum average annual rate of 30% after adjusting for inflation. A greater emphasis on outpatient care and the use of new therapies that increase life expectancy by reducing the frequency and severity of morbidity will decrease the future annual cost of treatment but will have a small effect on total economic costs because of substantial foregone earnings by persons with AIDS. Estimating the economic impact of this disease provides valuable information for formulating effective strategies to treat AIDS patients, to provide education for limiting the spread of the human immunodeficiency virus, and to achieve other health objectives.     

La Trypanosomose Humaine Africaine dans l’espace ivoiro-burkinabé : optimisation des stratégies de surveillance épidémiologique

The objective of this paper was to describe recent data from Burkina Faso and Côte d’Ivoire on Human African Trypanosomosis medical monitoring in order to (i) update the disease situation in these two countries that have been sharing important migratory, economic and epidemiological links for more than a century and (ii) to define the future strategic plans to achieve the goal of a sustainable control/elimination process. Results of active and passive surveillance indicate that all sleeping sickness patients diagnosed these last years in Burkina Faso were imported cases from Côte d’Ivoire. Nevertheless the re-introduction of the parasite is effective and the risk of a resumption of transmission exists. In Côte d’Ivoire, few cases are still diagnosed in several historical foci and the fear exists that the disease could reemerge in these foci or spread to other areas. In order to achieve a sustainable elimination of sleeping sickness in these two countries, control entities have to adapt their strategy to the different epidemiological contexts. At the exception of specific cases, the current disease prevalence no longer justifies the use of expensive medical surveys by exhaustive screening of the population. New disease control strategies, based on the exchange of epidemiological information between the two countries and integrated to the regular national health systems are required to target priority intervention areas. Follow-up in time of both treated patients and serological suspects that are potential asymptomatic carriers of parasite is also important. In parallel, researchers need to better characterize the respective roles of the human and animal reservoir in the maintenance of transmission and evaluate the different control strategies taken by National Control Programs in term of cost/effectiveness to help optimize them.     

Recent trends in cesarean section rates in Ontario

To assess the economic impact of HIV (human immunodeficiency virus) antibody screening among potential immigrants on Canada''s health care system we estimated the costs and benefits of such screening among the 160 135 immigrants who entered Canada in 1988 using the in-hospital costs of treating AIDS (acquired immune deficiency syndrome) over the 10 years after immigration. This economic model was based on current international HIV seroprevalence data, Canadian immigration statistics and estimates of disease progression. Between 343 and 862 of the immigrants were estimated to have been HIV seropositive; with the use of the enzyme-linked immunosorbent assay and the Western blot technique 310 to 780 of them would have been correctly identified as being seropositive, and 33 to 82 would have been incorrectly classified as being seronegative. Another 16 would have been falsely classified as being seropositive. There would have been 151 to 379 cases of AIDS from 1988 to 1998 among the immigrants identified as being HIV-positive. The estimated total cost of screening would have been $3.3 to $3.4 million. The in-hospital costs of treating HIV-infected immigrants in whom AIDS developed between 1989 and 1998 would have been $5.0 to $17.1 million. Accordingly, screening would have saved $1.7 to $13.7 million over the 10 years after immigration. However, we do not advocate screening on the basis of economic analysis alone and acknowledge that any policy regarding such screening must also incorporate social, legal and ethical considerations.     

Why Herd Size Matters – Mitigating the Effects of Livestock Crashes

Analysing the effect of pastoral risk management strategies provides insights into a system of subsistence that have persevered in marginal areas for hundreds to thousands of years and may shed light into the future of around 200 million households in the face of climate change. This study investigated the efficiency of herd accumulation as a buffer strategy by analysing changes in livestock holdings during an environmental crisis in the Saami reindeer husbandry in Norway. We found a positive relationship between: (1) pre- and post-collapse herd size; and (2) pre-collapse herd size and the number of animals lost during the collapse, indicating that herd accumulation is an effective but costly strategy. Policies that fail to incorporate the risk-beneficial aspect of herd accumulation will have a limited effect and may indeed fail entirely. In the context of climate change, official policies that incorporate pastoral risk management strategies may be the only solution for ensuring their continued existence.     

Giardia: an under-reported foodborne parasite

Foodborne zoonotic pathogens are a serious public health issue and result in significant global economic losses. Despite their importance to public health, epidemiological data on foodborne diseases including giardiasis caused by the enteric parasite, Giardia duodenalis, are lacking. This parasite is estimated to cause ～28.2 million cases of diarrhoea each year due to contamination of food, but very few foodborne outbreaks have been documented due to the limitations of current detection as well as surveillance methods. The current method for the recovery of Giardia cysts from food matrices using immunomagnetic separation requires further standardisation and cost reduction before it can be widely used. It also should incorporate downstream molecular procedures for genotyping, and traceback and viability analyses. Foodborne giardiasis can be potentially controlled through improvements in national disease surveillance systems and the establishment of Hazard Analysis and Critical Control Point interventions across the food chain. Studies are needed to assess the true prevalence and public health impact of foodborne giardiasis.     

Integrating spread dynamics and economics of timber production to manage Chinese tallow invasions in southern U.S. forestlands

Economic costs associated with the invasion of nonnative species are of global concern. We estimated expected costs of Chinese tallow (Triadica sebifera (L.) Small) invasions related to timber production in southern U.S. forestlands under different management strategies. Expected costs were confined to the value of timber production losses plus costs for search and control. We simulated management strategies including (1) no control (NC), and control beginning as soon as the percentage of invaded forest land exceeded (2) 60 (Low Control), (3) 25 (Medium Control), or (4) 0 (High Control) using a spatially-explicit, stochastic, bioeconomic model. With NC, simulated invasions spread northward and westward into Arkansas and along the Gulf of Mexico to occupy ≈1.2 million hectares within 20 years, with associated expected total costs increasing exponentially to ≈$300 million. With LC, MC, and HC, invaded areas reached ≈275, 34, and 2 thousand hectares after 20 years, respectively, with associated expected costs reaching ≈$400, $230, and $200 million. Complete eradication would not be cost-effective; the minimum expected total cost was achieved when control began as soon as the percentage of invaded land exceeded 5%. These results suggest the importance of early detection and control of Chinese tallow, and emphasize the importance of integrating spread dynamics and economics to manage invasive species.     

Is there safety in numbers? The effect of cattle herding on biting risk from tsetse flies

In sub-Saharan Africa, tsetse (Glossina spp.) transmit species of Trypanosoma which threaten 45-50 million cattle with trypanosomiasis. These livestock are subject to various herding practices which may affect biting rates on individual cattle and hence the probability of infection. In Zimbabwe, studies were made of the effect of herd size and composition on individual biting rates by capturing tsetse as they approached and departed from groups of one to 12 cattle. Flies were captured using a ring of electrocuting nets and bloodmeals were analysed using DNA markers to identify which individual cattle were bitten. Increasing the size of a herd from one to 12 adults increased the mean number of tsetse visiting the herd four-fold and the mean feeding probability from 54% to 71%; the increased probability with larger herds was probably a result of fewer flies per host, which, in turn, reduced the hosts' defensive behaviour. For adults and juveniles in groups of four to eight cattle, > 89% of bloodmeals were from the adults, even when these comprised just 13% of the herd. For groups comprising two oxen, four cows/heifers and two calves, a grouping that reflects the typical composition of communal herds in Zimbabwe, approximately 80% of bloodmeals were from the oxen. Simple models of entomological inoculation rates suggest that cattle herding practices may reduce individual trypanosomiasis risk by up to 90%. These results have several epidemiological and practical implications. First, the gregarious nature of hosts needs to be considered in estimating entomological inoculation rates. Secondly, heterogeneities in biting rates on different cattle may help to explain why disease prevalence is frequently lower in younger/smaller cattle. Thirdly, the cost and effectiveness of tsetse control using insecticide-treated cattle may be improved by treating older/larger hosts within a herd. In general, the patterns observed with tsetse appear to apply to other genera of cattle-feeding Diptera (Stomoxys, Anopheles, Tabanidae) and thus may be important for the development of strategies for controlling other diseases affecting livestock.     

Defining and evaluating the ecological restoration economy

For decades, industry groups and many media outlets have propagated the notion that environmental protection is bad for business. However, missing from this public debate has been a detailed accounting of the U.S. economic output and employment that are created through conservation, restoration, and mitigation actions, which we call the “Restoration Economy.” In this paper, we review related literature, including 14 local and state‐level case studies of privately funded environmental restoration projects. We also review federal and state government programs that fund restoration throughout the United States, revealing the complex nature of this sector. We find growing evidence that the restoration industry not only protects public environmental goods but also contributes to national economic growth and employment, supporting as many as 33 jobs per $1 million invested, with an employment multiplier of between 1.48 and 3.8 (the number of jobs supported by every restoration job) and an output multiplier of between 1.6 and 2.59 (multiplier for total economic output from investments). The existing literature also shows that restoration investments lead to significant positive economic and employment impacts and appear to have particularly localized benefits, which can be attributed to the tendency for projects to employ local labor and materials. While these initial figures are promising, the extent of environmental restoration activities and benefits at a national level is not yet well understood. Our findings reveal the need for a methodological framework for more accurately and broadly estimating the size of the U.S. restoration sector and its impact on the U.S. economy.     

Firm-level economic effects of HABS: A tool for business loss assessment

While the economic consequences of HABs may seem obvious, there is little empirical evidence to support the assertion or its magnitude relative to other environmental effects. As scientists learn more about the effectiveness of alternative HAB prevention, mitigation, and control strategies and agencies prepare for a suite of environmental events, information on potential economic losses are needed at the firm level to evaluate and justify continued HAB-related expenditures. To determine the extent of monetary losses that some firms may have incurred due to blooms of Karenia brevis (red tides) in Southwest Florida, 7 years of daily proprietary data were obtained from three beachfront restaurants and supplemented with environmental data from nearby weather stations. The statistical models revealed that reductions in daily sales ranged from $868 to $3734 (13.7%–15.3% on average) when red tide conditions were present. Estimated losses are compared to other environmental events and were found to coincide with those from other studies. The incidence of red tide events (as noted by each restaurant manager) corresponded with cell counts that averaged 180,853 cells/l as measured within 6 miles. Collectively this information supports the hypothesis of localized economic losses and provides a threshold cell count for future loss projections.     

Impact of Stakeholders Influence,Geographic Level and Risk Perception on Strategic Decisions in Simulated Foot and Mouth Disease Epizootics in France

Comparison of control strategies against animal infectious diseases allows determining optimal strategies according to their epidemiological and/or economic impacts. However, in real life, the choice of a control strategy does not always obey a pure economic or epidemiological rationality. The objective of this study was to analyze the choice of a foot and mouth disease (FMD) control strategy as a decision-making process in which the decision-maker is influenced by several stakeholders (government, agro-food industries, public opinion). For each of these, an indicator of epizootic impact was quantified to compare seven control strategies. We then determined how, in France, the optimal control strategy varied according to the relative weights of stakeholders and to the perception of risk by the decision-maker (risk-neutral/risk-averse). When the scope of decision was national, whatever their perception of risk and the stakeholders'' weights, decision-makers chose a strategy based on vaccination. This consensus concealed marked differences between regions, which were connected with the regional breeding characteristics. Vaccination-based strategies were predominant in regions with dense cattle and swine populations, and in regions with a dense population of small ruminants, combined with a medium density of cattle and swine. These differences between regions suggested that control strategies could be usefully adapted to local breeding conditions. We then analyzed the feasibility of adaptive decision-making processes depending on the date and place where the epizootic starts, or on the evolution of the epizootic over time. The initial conditions always explained at least half of the variance of impacts, the remaining variance being attributed to the variability of epizootics evolution. However, the first weeks of this evolution explained a large part of the impacts variability. Although the predictive value of the initial conditions for determining the optimal strategy was weak, adaptive strategies changing dynamically according to the evolution of the epizootic appeared feasible.     

Cost-effectiveness of the national dog rabies prevention and control program in Mexico, 1990–2015

BackgroundRabies is a viral zoonosis that imposes a substantial disease and economic burden in many developing countries. Dogs are the primary source of rabies transmission; eliminating dog rabies reduces the risk of exposure in humans significantly. Through mass annual dog rabies vaccination campaigns, the national program of rabies control in Mexico progressively reduced rabies cases in dogs and humans since 1990. In 2019, the World Health Organization validated Mexico for eliminating rabies as a public health problem. Using a governmental perspective, we retrospectively assessed the economic costs, effectiveness, and cost-effectiveness of the national program of rabies control in Mexico, 1990–2015.MethodologyCombining various data sources, including administrative records, national statistics, and scientific literature, we retrospectively compared the current scenario of annual dog vaccination campaigns and post-exposure prophylaxis (PEP) with a counterfactual scenario without an annual dog vaccination campaign but including PEP. The counterfactual scenario was estimated using a mathematical model of dog rabies transmission (RabiesEcon). We performed a thorough sensitivity analysis of the main results.Principal findingsResults suggest that in 1990 through 2015, the national dog rabies vaccination program in Mexico prevented about 13,000 human rabies deaths, at an incremental cost (MXN 2015) of $4,700 million (USD 300 million). We estimated an average cost of $360,000 (USD 23,000) per human rabies death averted, $6,500 (USD 410) per additional year-of-life, and $3,000 (USD 190) per dog rabies death averted. Results were robust to several counterfactual scenarios, including high and low rabies transmission scenarios and various assumptions about potential costs without mass dog rabies vaccination campaigns.ConclusionsAnnual dog rabies vaccination campaigns have eliminated the transmission of dog-to-dog rabies and dog-mediated human rabies deaths in Mexico. According to World Health Organization standards, our results show that the national program of rabies control in Mexico has been highly cost-effective.     

A new weed control strategy in onion culture

A new strategy combining modem hoeing technique and spray application has been developed in order to reduce the amount of herbicides down to 20% compared to common practice. The effects on weed control have been investigated as well as the impact on qualitative and quantitative harvest. In two large scale field trials and two years of testing the authors evaluated different hoeing techniques combined with band spray application and standard spray application, the minimal lethal herbicide dose method (MLHD). All varieties have been calculated for environmental impact as well as practical and economical means. These studies reveal crop losses due to improper weed control as well as losses due to herbicide stress. Detailed information on concentration depending impact of several herbicides have been correlated to their control of different weeds and the achieved yield. Two contrary effects influencing the total yield have been identified. The novel strategy is based on the knowledge of these complex effects which finally led to a well practicable and highly economic strategy that enables onion farmers to control weeds while reducing the amounts of herbicides down to approximately 20%.     

Economic implication of diseases in goats in India with reference to implementation of a health plan calendar

The role of goats in the economy of the rural resource poor in India and economic losses due to mortality and morbidity at micro and macro level is important. Goats contribute more than 52% of households’ total income towards nutrition and food security of the family of goat keepers. The mortality and morbidity losses due to diseases in goats were estimated at field level in Mathura district of Uttar Pradesh State, India. The mortality rates for small, medium and large categories of goat keeping were 32.8, 32.1 and 15.8% in kids and 31.2, 19.9 and 14.9% in adult goats, respectively. The losses due to diseases in goats scaled at national level were estimated at Rs. 11,720 million per annum. The adoption of prophylactic and preventive measures in goats could result in a net savings of Rs. 5144 million per annum to the economy of the country. The study demonstrates a need to use available technology to prevent diseases in goats.     

Estimating the economic costs of algal blooms in the Canadian Lake Erie Basin

Over the past two decades there has been a re-emergence of regular harmful algal blooms in Lake Erie due to increasing phosphorus loading, mainly from non-point agricultural sources. The Canadian and United States governments have jointly agreed to reduce phosphorus loadings to the lake in order to control the extent and severity of the blooms. Citizens on both sides of the border face a number of economic costs, both market and non-market, as a result of the blooms. This study values these costs for the Canadian portion of the Lake Erie basin economy using standard economic approaches that are widely applied within the world of cost-benefit analysis. The results suggest that algal blooms will impose equivalent annual costs equal to $272 million in 2015 prices over a 30-year period if left unchecked. The largest market costs will be imposed on the tourism industry ($110 million in equivalent annual costs) and the largest non-market costs will be borne by recreational users and those who place inherent value on the lake’s quality ($115 million in equivalent annual costs). Management action to reduce phosphorus loadings is found to be justified on economic grounds if the 30-year net present value of the reduction program is less than $1294 million (2015 Canadian dollars).     

The Monetary Burden of Cystic Echinococcosis in Iran

Cystic echinococcosis (CE) is a globally distributed parasitic infection of humans and livestock. The disease is of significant medical and economic importance in many developing countries, including Iran. However, the socioeconomic impact of the disease, in most endemic countries, is not fully understood. The purpose of the present study was to determine the monetary burden of CE in Iran. Epidemiological data, including prevalence and incidence of CE in humans and animals, were obtained from regional hospitals, the scientific literature, and official government reports. Economic data relating to human and animal disease, including cost of treatment, productivity losses, and livestock production losses were obtained from official national and international datasets. Monte Carlo simulation methods were used to represent uncertainty in input parameters. Mean number of surgical CE cases per year for 2000–2009 was estimated at 1,295. The number of asymptomatic individuals living in the country was estimated at 635,232 (95% Credible Interval, CI 149,466–1,120,998). The overall annual cost of CE in Iran was estimated at US$232.3 million (95% CI US$103.1–397.8 million), including both direct and indirect costs. The cost associated with human CE was estimated at US$93.39 million (95% CI US$6.1–222.7 million) and the annual cost associated with CE in livestock was estimated at US$132 million (95% CI US$61.8–246.5 million). The cost per surgical human case was estimated at US$1,539. CE has a considerable economic impact on Iran, with the cost of the disease approximated at 0.03% of the country''s gross domestic product. Establishment of a CE surveillance system and implementation of a control program are necessary to reduce the economic burden of CE on the country. Cost-benefit analysis of different control programs is recommended, incorporating present knowledge of the economic losses due to CE in Iran.     

Low temperature-dependent salmonid alphavirus glycoprotein processing and recombinant virus-like particle formation

Pancreas disease (PD) and sleeping disease (SD) are important viral scourges in aquaculture of Atlantic salmon and rainbow trout. The etiological agent of PD and SD is salmonid alphavirus (SAV), an unusual member of the Togaviridae (genus Alphavirus). SAV replicates at lower temperatures in fish. Outbreaks of SAV are associated with large economic losses of ~17 to 50 million $/year. Current control strategies rely on vaccination with inactivated virus formulations that are cumbersome to obtain and have intrinsic safety risks. In this research we were able to obtain non-infectious virus-like particles (VLPs) of SAV via expression of recombinant baculoviruses encoding SAV capsid protein and two major immunodominant viral glycoproteins, E1 and E2 in Spodoptera frugiperda Sf9 insect cells. However, this was only achieved when a temperature shift from 27°C to lower temperatures was applied. At 27°C, precursor E2 (PE2) was misfolded and not processed by host furin into mature E2. Hence, E2 was detected neither on the surface of infected cells nor as VLPs in the culture fluid. However, when temperatures during protein expression were lowered, PE2 was processed into mature E2 in a temperature-dependent manner and VLPs were abundantly produced. So, temperature shift-down during synthesis is a prerequisite for correct SAV glycoprotein processing and recombinant VLP production.