Economic and Geographic Impact of Equine Infectious Anemia in Louisiana

Linda Benedict, Kennedy, Gary A.  |  8/3/2009 11:59:21 PM

Photo of a horse

table 1.

Figure 1.

Gary A. Kennedy, William H. Green and Mark W. Murphey

In 1998, the equine industry contributed an estimated $41 million in gross farm income and an additional $89 million in value-added and related activities to Louisiana’s $1.5 billion animal industry. Of 10 recognized Louisiana animal commodities, the equine industry ranked fourth in 1998 in total value, following poultry, milk and cattle. Including horse production, the race horse industry, horse shows, youth programs and all activities that add value, the direct impact of the equine industry approaches $1 billion in Louisiana.

Equine Infectious Anemia (EIA or “Swamp Fever”) is a contagious viral disease of horses, mules and donkeys and is related to the human immunodeficiency (AIDS) virus. As with AIDS, no specific treatment or vaccine is available for EIA. Prevention and control of the disease is by testing, quarantine and destruction of infected animals. Insects may transmit EIA, and outbreaks tend to be geographic in nature. Louisiana has historically reported a high incidence of EIA. For example, in 1994, Louisiana had the highest per capita incidence of EIA in the nation with 326 positive animals from approximately 41,000 animals tested. The purpose of this study was to estimate the economic impact of this disease on the Louisiana economy and to examine its geographic incidence throughout the state.

EIA regulations vary

EIA regulations vary from state to state. Animals testing positive for EIA in Louisiana must be euthanized or sold for slaughter only. All animals located within 200 yards of an animal testing positive for EIA require a minimum 30-day negative test before a quarantine release is issued. Louisiana requires permanent identification in the form of a tattoo, an electronic chip, or a hot or cold brand and a mandatory annual test for every horse. In addition, animals changing ownership must have a negative test within six months.

Data on 673 animals testing positive for EIA from January 1995 through June 1998 were collected from the Louisiana Equine Infectious Anemia Test Program, maintained by the Louisiana Department of Agriculture and Forestry. Data collected included the owner’s name and address and the species, age, gender and origin of each infected animal identified during the time period. Data used in this study on animals testing positive for EIA represent approximately 94 percent of the population of EIA-positive animals for the study period. Data were not available on animals testing negative for EIA during the time period.

No statistical difference was found in the incidence of EIA between mares (314 reactors) and geldings (306 reactors). Stallions represent a much smaller segment of the population, and only 49 stallions tested positive for EIA during the study period.

Horses represented 93 percent of all EIA reactors in the data collected. The data included eight EIA-positive donkeys and 40 EIA-positive mules.

While EIA may infect an animal of any age, those between 2 and 20 years of age accounted for the majority of animals in this study.

Geographic impact of EIA

To determine a geographic impact of EIA in Louisiana, the state was divided into nine areas (Figure 1). Each area is relatively homogeneous with respect to climatic conditions and types of agricultural commodities produced. Animals testing positive for EIA were divided into categories by area and by the year of test. Results indicated that the Southwest Area accounted for 275 of the 673 EIA-positive animals for which location information was verified. However, the number of EIA-positive animals in the Southwest Area declined from 188 in 1995 to 25 in 1997, a decrease of 87 per-Acknowledgment The authors express appreciation to Dr. Maxwell Lea, state veterinarian, Louisiana Department of Agriculture and Forestry, for providing the data that made this research possible. cent. Annual totals in Figure 1 indicate that the statewide incidence of EIA in Louisiana is also declining each year. In 1995, there were 366 reactors statewide as compared to 134 in 1997, a decrease of 63 percent.

Economic impact of EIA

To estimate an economic impact, a mail survey was sent to owners who had animals infected with EIA between Jan. 1, 1995, and June 30, 1998, requesting information on use of the animal, method of disposal and an estimated value before and after infection. Survey results and data provided by the LSU Agricultural Center were used to estimate area and statewide average economic loss in the value of infected animals and the related value-added loss in feed, equipment and veterinary supplies and services resulting from the destruction of infected animals. Information was returned on 220 of the 673 EIA-positive animals in the data set.

An animal value before infection was indicated for 209 EIA-positive animals (Table 1). Nearly 90 percent (188) of EIA-positive horses reported in the survey were sold for slaughter. The remainder were euthanized.

Owners reported using about half the EIA reactors for pleasure purposes. Other uses included ranch work (24 percent), performance events (15 percent) and breeding (11 percent).

The average loss in value per animal was estimated to be $1,372 (mean value before infection minus mean slaughter value received). Considering that a total of 735 animals were infected with EIA over the study period, the estimated total loss in animal value was $1,008,420. Data obtained from the LSU Agricultural Center indicated that equine owners spent an average of $2,000 per animal per year in 1995 and 1996 and an average of $2,200 per animal in 1997 on feed, equipment, tack and veterinary supplies and services. This translates into an estimated value added and related loss of $4,699,600.

Combined with the loss in animal value, the total statewide loss was estimated to be $5,708,020. Continued emphasis on mandatory testing and regulation enforcement in all areas of the state is needed to ensure a continued decline in the incidence of EIA in Louisiana.


The authors express appreciation to Dr. Maxwell Lea, state veterinarian, Louisiana Department of Agriculture and Forestry, for providing the data that made this research possible.

Gary A. Kennedy, Assistant Professor; William H. Green, Associate Professor and Resident Veterinarian; and Mark W. Murphey, Assistant Professor, Department of Agricultural Sciences, Louisiana Tech University, Ruston, La. Kennedy is also Adjunct Assistant Professor, Department of Agricultural Economics and Agribusiness, LSU Agricultural Center, Baton Rouge, La.

(This article was published in the summer 1999 issue of Louisiana Agriculture)

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