Lindsey P. Garber

Salmonella enterica Serotype enteritidis in Table Egg Layer House Environments and in Mice in U.S. Layer Houses and Associated Risk Factors

SUMMARY. Prevalence was estimated for Salmonella enterica serotype enteritidis (SE) in layer house environments (n = 200 layer houses) and house mice (n = 129 layer houses) in 15 states throughout the United States. Environmental swabs were collected from manure, egg belts, elevators, and walkways. Live-catch rodent traps were placed for 4–7 days. Swabs and house mice were submitted to the laboratory for bacterial culture. Overall, 7.1% of layer houses and 3.7% of mice were culture positive for SE. The highest prevalence was in the Great Lakes region of the United States, and no SE was recovered from houses or mice in the southeast region. Presence of SE in layer houses was associated with age/molting, floor reared pullets, and number of rodents trapped. Cleaning and disinfecting houses between flocks was associated with a reduced risk. The prevalence of SE in mice from environmentally positive houses was nearly four times that of mice from environmentally negative houses.

Management and nutritional factors associated with the detection of Salmonella sp. from cattle fecal specimens from feedlot operations in the United States

In a convenience sample of 100 feedlot operations (included in the United States Department of Agriculture: Animal and Plant Health Inspection Service 1994 Cattle on Feed Evaluation), up to 25 cattle fecal samples were collected and tested for the presence of Salmonella from each of two pens (the pen which contained the most-recent arrivals, and the pen with cattle that had been on feed the longest). One or more Salmonella spp. were recovered from 38 (38.0%) of the 100 feedlots, 52 (26.0%) of the 200 pens and 273 (5.5%) of the 4977 fecal samples collected. Multivariable logistic regression indicated that feeding tallow and feeding whole cottonseed or cottonseed hulls within seven days prior to fecal sample collection was associated with an increased risk of finding Salmonella in a pen. Variables not found to be significantly associated with the detection of Salmonella in a pen included region, operation size, use of sprinklers, time on feed, type of cattle in the pen, number and concentration of cattle in a pen, feeding probiotics, and various other feeds.

Health status of preweaned dairy heifers in the United States

The first national estimates of mortality and morbidity for preweaned dairy heifers in the US were generated from monitoring heifers from 906 operations in 28 states prospectively using a daily diary card system. Results indicated that the cumulative mortality incidence risk from birth to 8 weeks of life was 6.3% with a peak of 1.9% during the first week of life. Season of birth was significantly associated with cumulative mortality incidence risk, and mortality risk was highest in the periods January to March and October to December. Cumulative incidence risk of diarrhea to 8 weeks of age was 24.6% with a peak of 15.4% during the second week of life. Diarrhea incidence risk varied by region, with the West having the highest incidence risk (30.5%) and the Northeast the lowest (19.2%), as well as by herd size, with the smallest herd size having the lowest reported incidence risk of diarrhea to 8 weeks of age (18.8%). Other reported 8 week cumulative disease incidence risks included listlessness, 10.0%; respiratory disease, 8.4%; dehydration, 4.1%; lameness or joint problems, 1.1%.

Description of Live Poultry Markets in the United States and Factors Associated with Repeated Presence of H5/H7 Low-Pathogenicity Avian Influenza Virus

Abstract In 2005 the National Animal Health Monitoring System conducted a survey in 183 live poultry markets throughout the United States. The objectives of this study were to describe characteristics of live poultry markets in the United States and to identify potential risk factors for markets to be repeatedly positive for low-pathogenicity avian influenza virus (LPAIV) H5/H7. A questionnaire was administered to market operators that included questions regarding types of birds and other animals in the market, biosecurity, and cleaning and disinfecting practices. A history of testing for avian influenza from March 2004 through March 2005 was obtained for each market. Cases were defined as markets with at least 2 positive LPAI/H5/H7 test results during the year (separate occasions), and controls were defined as markets that were tested at least twice during the year with all negative results. Markets in the North region (New York, New Jersey, Pennsylvania, New England) were larger than markets in the South (Florida, California, Texas) and were more likely to slaughter birds on-site. Testing for avian influenza virus (AIV) was performed more frequently in the North region than in the South region. Markets in the North region tested positive for H5 or H7 at 14.6% of the testing visits, and no markets in the South region tested positive for H5/H7 at any time during the year. Factors associated with repeated presence of LPAIV H5/H7 included number of times the market was cleaned and disinfected, being open 7 days per week, and trash disposal of dead birds.

Design and implementation of the United States National Animal Health Monitoring System 1995 National Swine Study.

The United States Department of Agricultures National Animal Health Monitoring System 1995 National Swine Study was designed to estimate management, health and productivity parameters on pig operations in the United States. Sixteen major swine-producing states that accounted for nearly 91% of June 1, 1995 swine inventory and nearly three-fourths of United States swine producers were included in the study. In the initial phase of the study, National Agricultural Statistics Service enumerators collected information from 1477 producers involved in all phases of swine production (farrowing, nursery, and grower/finisher). Of these, 405 operations with > or = 300 finisher pigs (with at least one finisher pig > or = 54 kg) participated in the subsequent component of the study, which involved on-farm visits by state and federal veterinary medical officers and animal health technicians, and which concentrated on the grower/finisher phase of production. Of those eligible to take part in the second phase of the study, participation was higher among independent producers (48.3%) than among contract producers (15.3%). Participation was also higher among operations that used advanced record-keeping systems (such as record cards for individual breeding hogs or a computer-based record-keeping system). Thus, study results could have been influenced by response biases. As a biosecurity measure, 40.5 +/- 2.1% of operations restricted entry to employees only. For operations that permitted non-employees to enter the premises, relatively few enforced other biosecurity measures on visitors (0.4 +/- 0.1% required feed-delivery personnel and livestock handlers to shower before entering the premises; 3.3+/- 0.9% required a footbath; and 7.0 +/- 1.5% required feed-delivery personnel and livestock handlers not to have visited another operation with pigs on that day). The most common method of waste storage (used by 49.9 +/- 3.8% of operations with > or = 300 finisher pigs) was below-floor slurry or deep pit.

Salmonella awareness and related management practices in U.S. urban backyard chicken flocks.

Raising chickens in urban settings is a growing phenomenon in the United States. The United States Department of Agricultures (USDA) National Animal Health Monitoring System (NAHMS) conducted a cross-sectional study to better understand health and management of privately owned chicken flocks, and Salmonella awareness among chicken owners, in three urban settings-Denver, Colorado; Los Angeles, California; and Miami, Florida. Feed stores in each city were visited by data collectors during summer 2010, and customers who owned chickens were asked to complete a questionnaire. A convenience sample of 449 feed store customers was selected, and 382 (85.1%) customers participated in the study. For analysis, a stratified random sample was assumed, with the strata being individual feed stores. Median flock sizes were 5, 11 and 19 chickens in Denver, Los Angeles and Miami, respectively. In all three cities, over three-fourths of flocks contained table egg chicken breeds on the day the questionnaire was completed. In Denver, 20.4% of flocks had another species of bird present in addition to chickens, compared with 65.6% of flocks in Los Angeles and 53.6% of flocks in Miami. At the time of data collection in 2010, less than 50% of respondents in Miami and Los Angeles (40.0 and 30.2%, respectively) were aware of a connection between poultry contact, such as contact with chicks or ducks, and Salmonella infection in people, compared to 63.5% of respondents in Denver. Urban chicken flock owners who completed the questionnaire in English were more likely to be aware of the connection between poultry contact and Salmonella, compared with respondents who completed the questionnaire in Spanish (OR=3.5). The likelihood of Salmonella awareness was also higher for respondents who had heard of USDAs Biosecurity for Birds educational campaign and for respondents who sold or gave away eggs from their flocks (OR=2.5 and 2.8, respectively). Study findings demonstrate the importance of reaching the Spanish speaking population when creating educational outreach programs to reduce Salmonella infections in people who have live poultry contact.

Factors Associated with Highly Pathogenic Avian Influenza H5N2 Infection on Table-Egg Layer Farms in the Midwestern United States, 2015.

SUMMARY A case-control study was conducted among commercial table-egg layer and pullet operations in Iowa and Nebraska, United States, to investigate potential risk factors for infection with highly pathogenic avian influenza (HPAI) H5N2. A questionnaire was developed and administered to 28 case farms and 31 control farms. Data were collected at the farm and barn levels, enabling two separate analyses to be performed—the first a farm-level comparison of case farms vs. control farms, and the second a barn-level comparison between case barns on case farms and control barns on control farms. Multivariable logistic regression models were fit using a forward-selection procedure. Key risk factors identified were farm location in an existing control zone, rendering and garbage trucks coming near barns, dead-bird disposal located near barns, and visits by a company service person. Variables associated with a decreased risk of infection included visitors changing clothing, cleaning and disinfecting a hard-surface barn entryway, and ceiling/eaves ventilation in barns.

Design and implementation of the United States National Animal Health Monitoring System 1994–1995 Cattle on Feed Evaluation, and an evaluation of the impact of response biases

The 1994-95 Cattle on Feed Evaluation was a cooperative project (sponsored by the United States Department of Agriculture) involving Washington State University, state agricultural departments, and several agencies of the United States Department of Agriculture). The project focused on cattle-on-feed operations in 13 states that accounted for over 85% of the United States cattle on feed inventory. Participants were selected from National Agricultural Statistics Service list frames. Questionnaires were administered by telephone to operations with a one-time capacity of fewer than 1000 cattle; larger operations were visited twice to administer questionnaires. The participation rate for the first phase of the study was 56.7%. Ninety-one percent of eligible operations completed the second phase of the study. Data summarized from this national study can be used to profile management practices on cattle-feeding operations in the United States. Differences between participants and non-participants did not appear to be great. However, one does need to be mindful of the fact that a small percentage of the producers accounted for the vast majority of feedlot cattle marketed when interpreting the results.

Using quantitative disease dynamics as a tool for guiding response to avian influenza in poultry in the United States of America

Wild birds are the primary source of genetic diversity for influenza A viruses that eventually emerge in poultry and humans. Much progress has been made in the descriptive ecology of avian influenza viruses (AIVs), but contributions are less evident from quantitative studies (e.g., those including disease dynamic models). Transmission between host species, individuals and flocks has not been measured with sufficient accuracy to allow robust quantitative evaluation of alternate control protocols. We focused on the United States of America (USA) as a case study for determining the state of our quantitative knowledge of potential AIV emergence processes from wild hosts to poultry. We identified priorities for quantitative research that would build on existing tools for responding to AIV in poultry and concluded that the following knowledge gaps can be addressed with current empirical data: (1) quantification of the spatio-temporal relationships between AIV prevalence in wild hosts and poultry populations, (2) understanding how the structure of different poultry sectors impacts within-flock transmission, (3) determining mechanisms and rates of between-farm spread, and (4) validating current policy-decision tools with data. The modeling studies we recommend will improve our mechanistic understanding of potential AIV transmission patterns in USA poultry, leading to improved measures of accuracy and reduced uncertainty when evaluating alternative control strategies.

Distance to slaughter, markets and feed sources used by small-scale food animal operations in the United States

Distances to common production and marketing supply chain destinations may vary, and this has economic and animal health implications for small-scale food animal operations. Proximity to these destinations can affect the economic viability and marketing decisions of small-scale operations and may represent significant barriers to sustainability. Data were collected using a cross-sectional survey conducted by the US Department of Agricultures (USDA) National Animal Health Monitoring System in 2011 using a stratified systematic sample of 16,000 small-scale (gross annual farm sales between US