Financial Evaluation of Different Vaccination Strategies for Controlling the Bluetongue Virus Serotype 8 Epidemic in the Netherlands in 2008

Background: Bluetongue (BT) is a vector-borne disease of ruminants caused by bluetongue virus that is transmitted by biting midges (Culicoides spp.). In 2006, the introduction of BTV serotype 8 (BTV-8) caused a severe epidemic in Western and Central Europe. The principal effective veterinary measure in response to BT was believed to be vaccination accompanied by other measures such as movement restrictions and surveillance. As the number of vaccine doses available at the start of the vaccination campaign was rather uncertain, the Dutch Ministry of Agriculture, Nature and Food Quality and the Dutch agricultural industry wanted to evaluate several different vaccination strategies. This study aimed to rank eight vaccination strategies based on their efficiency (i.e. net costs in relation to prevented losses or benefits) for controlling the bluetongue virus serotype 8 epidemic in 2008 Methodology/Principal Findings: An economic model was developed that included the Dutch professional cattle, sheep and goat sectors together with the hobby farms. Strategies were evaluated based on the least cost - highest benefit frontier, the benefit-cost ratio and the total net returns. Strategy F, where all adult sheep at professional farms in the Netherlands would be vaccinated was very efficient at lowest costs, whereas strategy D, where additional to all adult sheep at professional farms also all adult cattle in the four Northern provinces would be vaccinated, was also very efficient but at a little higher costs. Strategy C, where all adult sheep and cattle at professional farms in the whole of the Netherlands would be vaccinated was also efficient but again at higher costs. Conclusions/Significance: This study demonstrates that a financial analysis differentiates between vaccination strategies and indicates important decision rules based on efficienc

Cost Analysis of Various Low Pathogenic Avian Influenza Surveillance Systems in the Dutch Egg Layer Sector

Background: As low pathogenic avian influenza viruses can mutate into high pathogenic viruses the Dutch poultry sector implemented a surveillance system for low pathogenic avian influenza (LPAI) based on blood samples. It has been suggested that egg yolk samples could be sampled instead of blood samples to survey egg layer farms. To support future decision making about AI surveillance economic criteria are important. Therefore a cost analysis is performed on systems that use either blood or eggs as sampled material. Methodology/Principal Findings: The effectiveness of surveillance using egg or blood samples was evaluated using scenario tree models. Then an economic model was developed that calculates the total costs for eight surveillance systems that have equal effectiveness. The model considers costs for sampling, sample preparation, sample transport, testing, communication of test results and for the confirmation test on false positive results. The surveillance systems varied in sampled material (eggs or blood), sampling location (farm or packing station) and location of sample preparation (laboratory or packing station). It is shown that a hypothetical system in which eggs are sampled at the packing station and samples prepared in a laboratory had the lowest total costs (i.e. J 273,393) a year. Compared to this a hypothetical system in which eggs are sampled at the farm and samples prepared at a laboratory, and the currently implemented system in which blood is sampled at the farm and samples prepared at a laboratory have 6 % and 39 % higher costs respectively

Agreement between four commercial diagnostic tests and routine bacteriological culture of milk to determine the udder infection status of dairy cows

Mastitis is usually treated based on clinical signs or somatic cell count information rather than on results of bacteriological culture of milk. In many countries an optimal mastitis treatment is considered important from the perspective of therapy efficacy, prudent antimicrobial use and farm economics. Farmers can optimize their mastitis treatment decisions if they know whether and which mastitis pathogen is involved. Information on the mastitis pathogen involved can be acquired from diagnostic mastitis tests such as culture-based tests. This study aimed to determine the agreement of four commercial culture-based mastitis tests with routine bacteriological culture of milk to determine the intramammary infection status of a quarter or cow. The commercial culture-based tests evaluated in this study were CHROMagar Mastitis (CHROMagar, France), Hardy Diagnostics Mastitis Triplate (Hardy Diagnostics, USA), Minnesota Easy Culture System II Tri-plate (University of Minnesota, USA), and VétoRapid (Vetoquinol, the Netherlands). We used 866 prospectively collected milk samples, routinely submitted to the bacteriological laboratory of GD Animal Health for routine bacteriological culture of milk from April to June 2016. Samples were cultured on routine bacteriological culture of milk and on the commercial culture-based tests. We calculated the agreement beyond chance of each commercial culture-based test result with the result of routine bacteriological culture using 2x2 contingency tables. Furthermore, inter-reader agreement was determined for 597 samples read by two masked readers. The agreement of the four commercial culture-based mastitis tests with routine bacteriological culture of milk for Gram-positive bacteria ranged from 0.14 (95% CI 0.11-0.16) using Hardy Diagnostics Mastitis Triplate to 0.25 (95% CI 0.22-0.28) using Minnesota Easy Culture System II Tri-plate. The agreement for Gram-negative bacteria was approximately 0.70 (95% CI 0.66-0.74) for all four commercial culture-based tests. The agreement for no growth ranged from 0.22 (95% CI 0.19-0.25) using Hardy Diagnostics Mastitis Triplate to 0.34 (95% CI 0.31-0.38) using VétoRapid. This category was affected by prevalence and bias as the prevalence adjusted and bias adjusted kappa ranged from 0.63 (95% CI 0.56-0.69) using CHROMagar Mastitis to 0.68 (95% CI 0.62-0.74) using Hardy Diagnostic Mastitis Triplate. Agreement between readers was almost perfect. Although only for Gram-negative bacteria a good agreement was found between commercial culture-based tests and routine bacteriological culture of milk, and further on-farm evaluations are needed to determine the effect of these findings on udder health, commercial culture-based tests are of added value to support decisions whether and how to treat cows with mastitis

Effects of a mastitis treatment strategy with or without on-farm testing

The etiology of mastitis is crucial information to use antimicrobials prudently for control and treatment. This study aimed to evaluate the effects of mastitis diagnosis and treatment strategies with on-farm testing, on cure, new intramammary infections (IMI), somatic cell count (SCC), and antimicrobial use, compared with farmers' current diagnosis and treatment strategies. The on-farm tests used, CHROMagar Mastitis (CHROMagar, Paris, France) and Minnesota Easy Culture System II Tri-plate (University of Minnesota, St. Paul, MN), both had etiological groups of IMI as result, being gram-positive growth, gram-negative growth, or culture negative. Two randomized controlled trials were conducted on 15 herds: trial 1 prospectively enrolled 155 cows with clinical mastitis, and trial 2 cross-sectionally included 78 cows with subclinical mastitis. In both trials, cows were randomly distributed over 3 equal-sized groups: a test group using CHROMagar, a test group using Minnesota, and a control group not using on-farm tests. Farmers decided whether or not to treat, and which antimicrobial treatment would be applied, using information available on the day of enrollment (control group), complemented with the on-farm test result 1 d after enrollment (both test groups). For clinical mastitis, an antimicrobial treatment was given in 58% of cases that used CHROMagar, in 80% that used Minnesota, and in 86% of the controls. For subclinical mastitis, an antimicrobial treatment was given in 50% of cases that used CHROMagar, in 54% that used Minnesota, and in 4% of the controls. Bacteriological cure rate of clinical mastitis was lowest in the CHROMagar group [odds ratio 0.18 (95%CI 0.03-0.99)] compared with the controls. Using the Minnesota on-farm test for subclinical mastitis diagnosis and treatments resulted in fewer new IMI on d 21 [odds ratio 0.06 (95%CI 0.00-0.74)] compared with the controls. Clinical cure rate, percentage of new IMI, and SCC on d 21 of clinical mastitis were comparable among the groups. Using on-farm tests in farmers' decision-making process resulted in more treatments in accordance with the etiology of mastitis than without on-farm testing. A diagnosis and treatment strategy with on-farm testing is advised in cows with clinical mastitis to enhance prudent antimicrobial use. For subclinical mastitis, however, on-farm testing may lead to an unacceptable increase in use of antimicrobials and thus should not be advised as the common approach

Distribution of Rabies control costs over different stakeholders and year in Flores Island.

<p>Distribution of Rabies control costs over different stakeholders and year in Flores Island.</p

Model inputs for the cost calculations of control measures in humans.

<p>^a Public servants/veterinarians/internist involved in rabies control measures in the past;</p><p>^b WHO <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-WHO1" target="_blank">[6]</a>;</p><p>^c Market price of water in Kupang was approximately Rp 75,000 per 4,000 liter (Rp 18.75 per liter). We assumed that a patient will use the water about 2 litre per minute, so for 15 minutes wound cleaning (as recommended by WHO <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-WHO1" target="_blank">[6]</a> and IHM <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-IHM1" target="_blank">[38]</a>) the water needed was about 30 litre. Thus the price of water equal Rp 563 (Rp 18.75×30) per patient.</p><p>^d Assumption based on the market price in Flores in October 2011.</p><p>^e Bingham, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-Bingham1" target="_blank">[10]</a>;</p><p>^f Patients received immunoglobulin injection, and series of vaccine injections;</p><p>^g BPS <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-BPS2" target="_blank">[55]</a>;</p><p>^h Loss of working time for patient was set 3 days to visit the hospital 3 times to get PET;</p><p>ⁱ WHO <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-WHO2" target="_blank">[58]</a>.</p><p>Transportation cost within the city since the people received pre-exposure treatment are public servants that working and living in the city.</p><p>Transportation cost from rural areas.</p

Model inputs for the cost calculations of control measures in dogs (Prices expressed at level of 2011).

<p>^a Indonesian Agriculture Ministry (IAM) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-IAM1" target="_blank">[53]</a>);</p><p>^b Public servants/veterinarians involved in rabies control measures in the past;</p><p>^c Vaccinators involved in the vaccination campaign;</p><p>^d Calculated: Multiplying by the average distance between the vaccination location and the Regency Agricultural Department (in average 100 km, rate of fuel consumption (in average 1litter per 50 km <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-http1" target="_blank">[54]</a>) and market price of fuel per litter (Rp 4,500 per litter).</p><p>^e The real cost paid to a public servant (Rp 100,000 per person per day) minus his/her transportation cost (Rp 9,000 per person per day);</p><p>^f Average number based on data from Husbandry Department of Sikka and Ngada regencies;</p><p>^g http://<a href="http://www.igloo-store.com/detail/IGLDUOSTCOOLG" target="_blank">www.igloo-store.com/detail/IGLDUOSTCOOLG</a> (accessed 24 June 2013);</p><p>^h Market price in Flores by asking the seller in the shopping center;</p><p>ⁱ Assumption based on the author knowledge;</p><p>^j Dog owners participated in the vaccination program;</p><p>^k BPS (Indonesian Statistics) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-BPS2" target="_blank">[55]</a>;</p><p>^l Calculated based on the average value of dogs year 2003, Rp 175,000 per dog (Hutabarat et al., <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-Hutabarat1" target="_blank">[23]</a>);</p><p>^m Calculated based on the daily wage and the number of dog culled per day per person (approximately 16 dogs per day per person);</p><p>ⁿ Michell and Kanowski <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-Mitchell1" target="_blank">[56]</a>;</p><p>^o Husbandry Department of Sikka Regency;</p><p>^p Center of Disease Investigation, Maros;</p><p>^q Ende Regency quarantine;</p><p>^r Indonesian quarantine (IQ) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-IQ1" target="_blank">[57]</a>;</p

Total number of registered dogs (<i>n</i>), vaccinated dogs (<i>n_vd</i>), culled dogs (<i>n_cd</i>), samples submitted (<i>n_ss</i>), and tested positive (<i>n_sp</i>) in Flores Island from 2000 to 2011.

<p>Source data: Husbandry Department of East Nusa Tenggara Province. These data were registered by each Regency Husbandry Department in Flores Island as part of vaccination campaign. In case the dog owners and their dogs were not present at time of registration, the dogs were not accounted for. For example in Sikka regency, the dogs of approximately 30% of the dog owners were not registered for this reason in 2012 (Personal communication, Dr. Sikko). As a result the registered number underestimates the actual size of the dog population.</p><p>^a Windiyaningsih et al., <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-Windiyaningsih1" target="_blank">[9]</a>.</p

The number of bitten human by rabies suspected dogs and post exposure treatments (PET) in Flores Island during 2000–2011.

<p>Source data: Human Health Department of East Nusa Tenggara Province.</p><p>^a Windiyaningsih et al., <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0083654#pone.0083654-Windiyaningsih1" target="_blank">[9]</a>.</p

Cost of Rabies control measures in humans.

<p>We assumed that the costs of pre-exposure treatment were the same over time.</p><p>This assumption is based on the costs of pre-exposure treatment control measure in 2011.</p