Hughes, Randi Catherine (2011-05). Assessment of U.S. Agriculture Sector and Human Vulnerability to a Rift Valley Fever Outbreak. Master's Thesis. Thesis uri icon


  • Foreign animal disease outbreaks can cause substantial economic losses. Policy makers need information on both the vulnerability of the food supply to disease epidemics and the impacts of alternative protection actions. This research focused on the assessment of the U.S. agricultural sector and human vulnerability to a Rift Valley Fever (RVF) outbreak and the value of a select set of alternative disease control strategies. RVF is a vector-borne, zoonotic disease that affects both livestock and humans; thus both animal and human consequences of an outbreak were examined. This research was conducted in two parts. Livestock impact assessment used an integrated epidemic/economic model to examine the extent of RVF spread in the animal population and its consequences plus the outcome of implementing two different control strategies: emergency vaccination and larvicide vector control. The number of infected, aborted, and dead animals is best controlled by coupling vaccination along with larvicide, but results in the second highest median national welfare loss. Therefore, careful decisions must be made as to what actions should be taken. Total national producer welfare is reduced with each scenario, and is more severe than the total national welfare loss (producer, consumer, and processor together). Consumer welfare is increased with each scenario due to a drop in prices of some commodities, and in some instances, an increase in supply as well. The majority of the national welfare loss can be attributed to the producers' and processors' loss in welfare. The highest damages are seen in the regions of the outbreak such as the South Central (SC). Other regions such as the Corn Belt, Lake States, and South East regions also see high damages due to price changes. The outbreak did not have substantial price effect on dairy products, but did have noticeable price changes for live cattle such as heifer calves, stocked yearling, and dairy calves. Prices for substitutes such as pork, chicken, and turkey experienced a price reduction, which can also be a factor resulting in consumer welfare gains. Human impact assessment utilized an inferential procedure for estimating the human consequences which comprise of a cost of illness calculation to assess the dollar cost of human illnesses and deaths, as well as a Disability Adjusted Life Year calculation to give an estimate of the burden of disease on public health as a whole. With potential costs above $2 billion for human illness, and with this number not accounting for loss or damages to other sectors of the economy, it can be highly probable that investing in a human vaccination campaign can be cost-effective and possibly cost-reducing. This cost along with the economic loss of the agriculture sector suggests substantial potential losses to the U.S. if this hypothetical situation were to become reality. Combining total loss estimates from the cost of illness and ASM models, potential damage of a RVF outbreak could range from 121 million to 2.3 billion US 2010$. The results of this study show the economic damages of an outbreak in the livestock population being much greater relative to the outbreak in the human population (roughly 16 times greater). It should be pointed out that both cost estimates are most likely under estimated. The animal outbreak is not incorporating all susceptible livestock (e.g. hogs and goats), and the human illness is not incorporating other damages to society (e.g. damages due to loss of tourism). By providing estimates on the potential economic outcomes, policy makers can better choose where, when, and how to invest their resources.

publication date

  • May 2011