In recent years, there has been much discussion of potential threats to US agriculture from bioterrorism. Of particular concern is the possibility that a foreign animal disease such as FMD could be intentionally introduced into the US livestock population. As seen with the 2001 FMD outbreak in the United Kingdom, a devastating epidemic may result when contagious animals pass undetected through high-density locations, such as livestock sales yards.1 A study2 of pigs exhibited at the 2002 Indiana State Fair found that livestock exhibitions provide conditions suitable for epidemics to occur. Although it is evident that there is a potential risk for such diseases to pass through or originate at such events, the true risk livestock exhibitions pose is affected by the biosecurity precautions taken by organizers and exhibitors.
During the busiest week of the 2005 California State Fair, approximately 1,700 animals were housed in the livestock pavilion, and over the 4 weeks of the fair, a total of approximately 5,000 livestock animals were housed at the fairgrounds. Although the number of animals that passed through the fair facilities during the 2005 California State Fair was far lower than the number reported to have passed through sales yards in the United Kingdom prior to diagnosis of the 2001 FMD outbreak, there were important similarities between the 2 events, in that exhibited animals came from a variety of locations prior to the fair and dispersed to numerous locations afterwards.
There is little information available about how far livestock travel to attend livestock exhibitions such as fairs and shows or how frequently livestock are exhibited at such events. Thus, there is little understanding of how great a threat livestock exhibitions could be to US agriculture in the event that animals with an undiagnosed disease were exhibited. The purposes of the study reported here were to gain specific knowledge about the habits of individuals exhibiting livestock at the 2005 California State Fair in Sacramento; to ascertain biosecurity measures taken by livestock exhibitors before, during, and after the fair; to determine the types of contacts made between exhibited animals and animals not at the fair; and to determine the distances traveled by animals exhibited at the fair and at other livestock exhibitions visited by this population.
Materials and Methods
Sampling strategy—General information regarding the 2005 California State Fair, including show schedules and sections, number of livestock to be exhibited in each section, and county and zip code of origin of all livestock exhibited, was obtained from the State Fair livestock show office. During August and September 2005, researchers from the Center for Animal Disease Modeling and Surveillance at the University of California, Davis, attended livestock shows held on 3 days during the fair. Visits were scheduled during show days for 3 of the 5 livestock exhibition sections.
While at the fair, researchers walked throughout the livestock exhibition area and approached individuals who appeared to be associated or working with livestock, asking them to complete a survey regarding their biosecurity and showing practices. Because certain breeds and species were located in specific areas of the exhibition hall, all areas were visited to ensure an equal chance of participation for all individuals exhibiting livestock, regardless of species or breed. If a given breed was in the show ring when that area of the exhibition hall was initially visited, a second visit was performed to ensure that those exhibitors had an equal chance of completing a survey. While visiting each area in the exhibition hall, researchers walked down aisles adjacent to show animals or situated themselves at exhibitor congregation areas and approached all apparent exhibitors, explaining the purpose of the study and asking exhibitors to participate. Exhibitors could refuse to participate or request to participate later. Surveys were filled out by the exhibitors, unless they asked to dictate their answers to a researcher. If multiple exhibitors maintained their animals at the same farm or facility, a single exhibitor was asked to complete the survey, but to provide information for all animals from that farm or facility. No personally identifiable information was collected or made available to the investigators. With no way to verify the answers given, it was assumed that all collected responses were correct. Prior to survey distribution, authorization for the study was received from the University of California's Institutional Review Board.
Survey questions—Questions in the survey asked about the species and types of animals exhibited; the number of animals of each species or type the exhibitor had brought to the fair; the biosecurity measures employed before, during, and after the fair; whether the animals would return to a commercial facility and, if so, the facility type; whether the exhibitor had attended other livestock exhibitions during the past 12 months and, if so, the dates and names of these exhibitions along with the number, species, and types of animals exhibited; and the zip code, county, and approximate location where exhibited animals were routinely maintained.
Data analysis—For analysis of distance data, participant zip codes were geocoded by zip code centroid. The location of the 2005 California State Fair was also geocoded, and the straight-line distance between each participant's zip code and the fair was calculated. In addition, a list of other livestock exhibitions was created from participants' responses regarding exhibitions they had attended in the past 12 months. The addresses for these exhibitions were found online and geocoded by use of a commercial georeferencing service.a Straightline distances from each participant's zip code to each of the other exhibitions attended were then calculated. Participants were grouped according to the livestock exhibition sections they exhibited in during the 2005 California State Fair.
Statistical analysis—In preparation for further analyses, survey responses were evaluated for significant differences among exhibitor groups. Survey results were summarized by use of descriptive statistics in a spreadsheet program,b and nonparametric tests were performed with standard softwarec to identify significant differences. For all analyses, values of P ≤ 0.05 were considered significant. When a Kruskal-Wallis test was performed and a significant difference observed, an ex post test was performed on each pair to ascertain which pairs were different from each other.3
Results
A total of 5,042 animals were exhibited during the course of the 2005 California State Fair. Exhibited livestock were allocated to 5 sections on the basis of species or production type, and livestock were exhibited a total of 23 days, with exhibition time for each section ranging from 4 to 6 days. Section 1 consisted of Miniature Hereford cattle, Boer goats, and Angora goats; these animals were exhibited between August 11 and August 14. Section 2 consisted of junior livestock beef, sheep, swine, and meat goats; these animals were exhibited between August 16 and August 21. Section 3 consisted of junior and open dairy cattle and goats and Pygmy goats; these animals were exhibited between August 24 and August 28. Section 4 consisted of open beef and Nigerian dwarf goats; these animals were exhibited between August 29 and September 1. Section 5 consisted of open beef, open sheep, open swine, and llamas; these animals were exhibited between September 2 and September 5.
Researcher visits to the fair took place during sections 2, 3, and 4. Surveys were completed by 137 exhibitors during these visits (61 [44%] during section 2 of the fair, 50 [37%] during section 3, and 26 [19%] during section 4). Approximately 95% of the exhibitors who were invited to participate in the study completed a survey.
Three survey respondents did not provide information regarding their county of origin; however, it was possible to ascertain county of origin for these respondents on the basis of address information they provided. Overall, 132 (96%) of the 137 respondents came from California, with respondents representing 40 of California's 58 counties. The remaining 5 (4%) respondents had come from other states. By comparison, 756 (94%) of the 805 total fair entrants were from California, representing 48 of the 58 counties, and 49 (6%) were from other states.
Eighteen (14%) of the 132 survey respondents from California were from Sacramento County, 13 (10%) each were from Stanislaus and San Joaquin counties, 8 (6%) were from Fresno County, and 7 (5%) were from Merced County. Five or fewer respondents were from each of the other represented counties, with 11 counties represented by only 2 respondents and 14 counties represented by a single respondent. Overall, 77 (10%) of the 756 total fair entrants from California were from Sacramento County, 63 (8%) were from Stanislaus County, 59 (8%) were from Sonoma County, 56 (7%) were from San Joaquin County, 33 (4%) were from Merced County, and 32 (4%) were from Fresno County. Three counties were represented by only 2 fair entrants, and 2 counties were represented by a single entrant each.
For survey respondents, median calculated straightline distance from farm of origin to the fair location was 133 km (range, 13 to 1,135 km; 1 km = 0.62 mile). Median calculated straight-line distances were 213 km (range, 21 to 1,135 km) for respondents exhibiting in section 4 (beef cattle), 119 km (range, 19 to 737 km) for respondents exhibiting in section 2 (junior exhibitors), and 114 km (range, 13 to 797 km) for respondents exhibiting in section 3 (dairy cattle and goats). All groups were found to be significantly (P < 0.001) different from each other.
When the 2005 California State Fair was included, median number of livestock exhibitions attended by respondents during the past 12 months was 3 (range, 1 to 7). Respondents from California reported that they had attended exhibitions in 13 states during the past 12 months. Of the 293 exhibition attendances reported by respondents, 255 (87.0%) were located in California; 8 (2.7%) were located in Nevada; 7 (2.4%) were located in Colorado; 5 (1.7%) were located in Utah; 4 (1.4%) each were located in Arizona, Kentucky, and Wisconsin; and 1 (0.3%) each was located in Kansas, Oklahoma, Pennsylvania, Tennessee, Texas, and Washington.
The distance respondents had traveled to livestock exhibitions during the past 12 months ranged from 0.5 to 4,412 km. Median calculated straight-line distances traveled to livestock exhibitions during the past 12 months were 52 km (range, 0.5 to 3,579 km) for respondents exhibiting in section 2, 88 km (range, 0.6 to 4,412 km) for respondents exhibiting in section 3, and 193 km (range, 5 to 2,815 km) for respondents exhibiting in section 4. All groups were significantly (P < 0.001) different from each other. Attendance at fairs differed significantly by month (P = 0.004), and of the 293 livestock exhibition attendances reported by respondents for the 12 months prior to the 2005 California State Fair, 192 (66%) had occurred in May through August.
Thirty-five (26%) of the 137 respondents indicated that they exhibited a combination of species at the 2005 California State Fair (Table 1). Twenty-six (74%) of these 35 respondents exhibited during section 2 (junior exhibitors), which was attended by many 4-H club and Future Farmers of America participants.
Characteristics of animals for 137 individuals exhibiting livestock at the 2005 California State Fair.
Animals shown | No. (%) of exhibitors | No. of animals shown | No. (%) of animals returned home | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dairy cattle | 30 (22) | 185 | 185 (100) | ||||||||||||||||
Beef cattle | |||||||||||||||||||
Breeding | 27 (20) | 180 | 176 (99) | ||||||||||||||||
Market | 3 (2) | 22 | 15 (68) | ||||||||||||||||
Goats | |||||||||||||||||||
Meat breeding | 0 (0) | 0 | 0 (0) | ||||||||||||||||
Meat market | 6 (4) | 27 | 24 (89) | ||||||||||||||||
Dairy | 12 (9) | 163 | 163 (100) | ||||||||||||||||
Pygmy | 6 (4) | 75 | 75 (100) | ||||||||||||||||
Sheep | |||||||||||||||||||
Meat market | 8 (6) | 41 | 36 (88) | ||||||||||||||||
Breeding | 2 (2) | 47 | 47 (100) | ||||||||||||||||
Swine | |||||||||||||||||||
Market | 8 (6) | 62 | 56 (90) | ||||||||||||||||
Breeding | 0 (0) | 10 | 10 (100) | ||||||||||||||||
Mixed* | 35 (26) | NA | NA | ||||||||||||||||
Total |
*This included 5 exhibitors showing dairy cattle, 14 showing breeding beef cattle, 15 showing market beef cattle, 2 showing breeding meat goats, 8 showing market meat goats, 4 showing dairy goats, 1 showing Pygmy goats, 11 showing market meat sheep, 9 showing breeding sheep, 8 showing market swine, and 3 showing breeding swine.
NA = Not applicable.
A total of 812 animals were exhibited by the 137 survey respondents (Table 1), accounting for 22% of the 3,540 animals exhibited at the fair during the 3-week period of data collection. Respondents indicated that 787 (97%) of these 812 animals would be returned home after the fair, with the remaining 25 (3%) animals believed to have been sold during the fair's livestock auction. Respondents who exhibited dairy cattle, dairy goats, pygmy goats, breeding sheep, and breeding swine indicated that they expected to take all of their animals back to their farm of origin.
Overall, 78 (57%) of the 137 respondents reported that their animals would be returned to a commercial livestock facility after the fair. This included animals returned to beef operations (26 respondents), dairy cattle operations (20), a dairy heifer operation (1), dairy goat operations (2), another type of goat operation (1), sheep operations (4), swine operations (3), and mixed animal operations (11). Ten respondents indicated that their animals would be returned to a commercial livestock facility after the fair but did not indicate the type of operation. Overall, 458 (58%) of the 787 animals that respondents expected to bring home after the fair were expected to be returned to commercial livestock facilities.
Straight-line distance traveled to livestock exhibitions in the past 12 months for animals returned to commercial operations (median, 88 km; range, 0.6 to 4,412 km) was not significantly (P = 0.118) different from distance for animals returned to noncommercial operations (median, 62 km; range, 0.5 to 3,579 km).
Exhibitors were asked about the biosecurity measures they took before, during, and after the fair. Nine (7%) of the 137 respondents indicated that they did not take any particular biosecurity precautions before arriving at the 2005 California State Fair, and 14 (10%) indicated that they did not take any particular biosecurity precautions while at the fair (Table 2). The most common biosecurity measure taken before the fair was to check animals thoroughly before arriving (104 [76%] respondents). The most common biosecurity measure taken while at the fair was avoiding sharing equipment with other exhibitors (83 [61%]). Although 68 (50%) respondents indicated that they took measures to prevent their animals from making physical contact with other animals, only 32 (23%) disinfected pens prior to housing their animals in them. Although 52 (38%) respondents indicated that they used hand sanitizer before touching other animals, only 7 (5%) required fair visitors to use hand sanitizer before touching the respondent's animals. Only 36 (26%) respondents indicated that they quarantined their animals when returning to their farm of residence after the fair. Washing show clothing and tools was the most common biosecurity measure taken after the fair (92 [67%]). Fifty-five (40%) respondents indicated they disinfected equipment after returning from the fair. The most commonly reported disinfectant was bleach, with some respondents indicating that they used other products, such as chlorhexidine and peroxygen compounds.
Biosecurity practices of individuals exhibiting livestock at the 2005 California State Fair.
Biosecurity practice | No. (%) who used the biosecurity measure | ||
---|---|---|---|
Before the fair | During the fair | Before the fair | |
Check animals thoroughly | 104 (76) | NA | NA |
Vaccinate animals | 85 (62) | NA | NA |
Disinfect truck and trailer | 50 (36) | NA | 50 (37) |
Disinfect boots and shoes | 27 (19) | 12 (9) | 19 (14) |
Avoid sharing equipment | NA | 83 (61) | NA |
Prevent physical contact with other animals | NA | 68 (50) | NA |
Use hand sanitizer before touching other animals | NA | 52 (38) | NA |
Prevent visitors from touching animals | NA | 51 (37) | NA |
Disinfect pens prior to housing | NA | 32 (23) | NA |
Make visitors use hand sanitizer | NA | 7 (5) | NA |
Wash show clothes and tools | NA | NA | 92 (67) |
Disinfect equipment | NA | NA | 55 (40) |
Quarantine animals | NA | NA | 36 (26) |
Take other precautions | 13 (11) | 16 (12) | 15 (11) |
No precautions taken | 9 (7) | 14 (10) | 12 (9) |
Did not respond | 4 (3) | 6 (4) | 7 (5) |
NA = Not applicable.
Thirty of the 36 respondents who stated that they quarantined their animals after returning home from the fair provided information on duration of the quarantine period. Twelve indicated they quarantined their animals ≤ 7 days, and 10 indicated they quarantined their animals 8 to 14 days, with the remaining 8 indicating that they quarantined their animals for longer periods. Two respondents indicated that they kept their show animals separate at all times. Twenty-one (27%) of the 78 respondents who took their animals back to a commercial facility quarantined them on their return.
Discussion
Results of the present study indicated that there was extensive movement of livestock among exhibitions in California, posing a potential threat for widespread dispersion of disease throughout the state and beyond. This extensive movement of livestock should be of concern to regulatory veterinarians who are faced with the potential spread and subsequent control of exotic diseases such as FMD. The high percentage of animals exhibited at the 2005 California State Fair that were returned to commercial livestock facilities, combined with the low quarantine rate, puts the commercial livestock population at risk should animals exhibited at the State Fair be exposed to FMD or some other contagious disease. The most common duration of quarantine among those who did quarantine animals when returning from the fair was ≤ 7 days. If a subclinically infected animal had been brought to the fair, it may not have shown clinical signs prior to leaving the fair, depending on the duration of the exhibition period for that particular breed or species, and could potentially infect other animals or contaminate equipment, clothing, other animals, fair exhibitors, or even fair visitors while at the fair. Importantly, if, for example, an animal were to be exposed to FMD while at the fair, there is a high likelihood that no clinical signs would be visible during a 7-day quarantine period after returning from the fair, and detection of the disease could be missed.4,5 Therefore, quarantine periods lasting longer than 7 days should be recommended as the probability of detection will be greater than if a quarantine period of ≤ 7 days or no quarantine period is used.
Observing clinical signs in infected animals would require careful examination, yet exhibitors themselves did not always check their animals' overall health before arriving at the fair. This increases the importance of requiring a physical examination by a veterinarian on-site before giving animals clearance to enter the show facilities. Typically, however, only those animals that are obviously unhealthy or that have unsightly marks such as scabs, regardless of their cause, at the time of inspection are denied entry. Clinically normal animals may be infected with FMD virus,6,7 and these animals may not be identified during a preentry examination. In conversation with various exhibitors, researchers found that other livestock exhibitions these individuals attended did not always require health examinations on arrival, which could increase the potential risk of disease transmission at these other events. There were mixed feelings among the exhibitors about the preentry health examination at the California State Fair, with most believing it to be a good idea, but several seeing it as an unnecessary inconvenience.
Results of our survey suggested that few exhibitors used disinfectants. There appeared to be little consideration by exhibitors that disease transmission to and from their animals could occur via the facilities where animals would be housed and the vehicles used to transport them. Few exhibitors disinfected or cleaned the site where their animals would be housed during the fair or disinfected their trucks and trailers after the fair. The last 3 show periods (August 24 through September 5) ran back-to-back, and there were no days during this time that livestock were not present in the livestock pavilion. Although state fair management cleans livestock areas, removing all bedding, between exhibitions, the area is not disinfected unless done so by the exhibitors.
A total of 920,768 members of the general public attended the 2005 California State Fair. These visitors had access to the livestock barns, were able to move freely through the various aisleways, and could come into contact with the animals. With this high volume of fair visitors moving through the livestock barns and their ability to make physical contact with the animals, there was the potential that a disease could be accidentally or intentionally introduced, particularly because few exhibitors required visitors to use hand sanitizer. There is also a risk of disease transfer from animals to people at events where livestock are present,8 and it has been suggested that frequent hand washing and use of hand sanitizer may reduce the risk of disease spreading to people and among animals.9
During the 2001 FMD outbreak in the United Kingdom, a contagious animal passed undetected through an area of high animal density, spreading the disease rapidly over a great area and causing major losses. Nine percent of the United Kingdom national herd was slaughtered, and the cost of compensation alone was in excess of $200 million,1 with the overall cost to agriculture and the food chain estimated at $5.5 billion.10 California's number one cash crop is milk, with 16.6 billion kg (36.5 billion lb) of milk produced by 1.73 million dairy cows at a value of $5.37 billion in 2004.11 If a disease such as FMD were to affect the California livestock industry, the results to the state and, potentially, the nation could be devastating.12 Therefore, all reasonable measures to reduce the risk of disease transmission at livestock exhibitions should be taken. Our results, however, reveal that there needs to be a greater awareness among livestock exhibitors about the risks involved with showing animals, the precautions that can be taken, and the signs of disease they should be watching for. We found that livestock exhibitors may travel great distances to attend exhibitions and that such exhibitions occur on a year-round basis. The low percentages of respondents who used biosecurity measures or quarantined their animals after returning home from the 2005 California State Fair illuminate areas of potential disease transmission risk. Veterinarians whose clients show at livestock exhibitions should educate those individuals about necessary biosecurity precautions that can be taken before, during, and after transporting livestock to an exhibition to reduce the risk of disease spread. Veterinarians should also make their clients aware of the clinical signs of all major livestock diseases. Further, we recommend that to reduce the potential risk of disease transmission, all livestock exhibitions perform preentry health inspections, disinfect facilities where animals are housed, and install devices containing hand sanitizer at locations readily accessible to exhibitors, visitors, and livestock judges.
ABBREVIATION
FMD | Foot-and-mouth disease |
Tele Atlas EZ-Locate geocoding server, Tele Atlas North America Inc, Lebanon, NH.
Microsoft Office Excel 2003, Microsoft Office Professional Edition 2003, Microsoft Corp, Redmond, Wash.
SPSS, version 12.0.1 for Windows, SPSS Inc, Chicago, Ill.
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