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Biomedical subjects

W E Morrow

Publications and source records attributed to W E Morrow.

16 recordsLinked to original sources
PubMed2004

Salmonella enterica serovars from pigs on farms and after slaughter and validity of using bacteriologic data to define herd Salmonella status.

The primary objective of this study was to evaluate the validity of using data obtained from slaughtered pigs for farm-level epidemiologic studies of Salmonella. The study involved groups of pigs from five farms. Salmonella isolates were obtained from on-farm samples, and a total of 370 on-farm and an additional 486 isolates from samples collected after commercial slaughter were subsequently tested. Preharvest samples included feces of individual animals from defined groups of nursery and finishing pigs on commercial farms and swabs from trucks. Postslaughter samples were cecal contents and mesenteric lymph node samples. The concordance between Salmonella serovars isolated from on-farm samples and those serovars isolated after slaughter varied widely among farms. Results of paired lymph node and cecal cultures were strongly associated (odds ratio, 7.0), but the agreement between on-farm and postslaughter results at the pig level was poor (kappa = 0.34). The results support recent findings that risk of exposure to Salmonella during transport and lairage remains a concern under contemporary industry conditions. The findings further imply that slaughter plant studies based on phenotyping of Salmonella alone (such as serovars) may not reliably indicate the Salmonella status of commercial swine farms.

Abattoirs↗
PubMed2004

Characterization of antimicrobial-resistant phenotypes and genotypes among Salmonella enterica recovered from pigs on farms, from transport trucks, and from pigs after slaughter.

The main objectives of this study were to determine antimicrobial resistance patterns among Salmonella serotypes and to evaluate the role of transport trucks in dissemination of antimicrobial-resistant strains of Salmonella. Salmonella from groups of nursery and finishing pigs on farms, from trucks, and from pigs after slaughter were compared using serotyping, patterns of antimicrobial resistance, and pulsed-field gel electrophoresis patterns. The five farms included in the study yielded 858 isolates representing 27 Salmonella serovars. The most common resistance observed (80% of all isolates) was to tetracycline; resistance to ampicillin (42%), chloramphenicol (31%), amoxicillin/clavulanic acid (30%), and piperacillin (31%) also were common. We found a correlation between serovar and antimicrobial resistance. High correlation was found between Salmonella Typhimurium var. Copenhagen and chloramphenicol resistance (Spearman rank correlation, rho = 0.7). Multidrug resistance was observed primarily in Salmonella Typhimurium var. Copenhagen (94%) and Salmonella Typhimurium (93%) and was much less common in the other common serovars, including Salmonella Derby (7%) and Salmonella Heidelberg (8%). Of the 225 isolates exhibiting the most common pentaresistance pattern in this study, amoxicillin/clavulanic acid-ampicillin-chloramphenicol-piperacillin-tetracycline, 220 (98%) were Salmonella Typhimurium var. Copenhagen, and 86% of the isolates of this serovar had this pattern. Isolates from the trucks were similar, based on pulsed-field gel electrophoresis patterns, to those from the cecum and mesenteric lymph nodes of pigs on two of the farms, suggesting the probable infection of pigs during transport. Class I integrons were also common among various serovars.

Animals↗
PubMed2000

Antimicrobial resistance of Salmonella isolates from swine.

We examined the antimicrobial resistance of 1,257 isolates of 30 serovars of Salmonella enterica subsp. enterica isolated from swine. Serovars Typhimurium and Typhimurium var. Copenhagen were widespread and were frequently multidrug resistant, with distinct resistance to ampicillin, kanamycin, streptomycin, sulfamethoxazole, and tetracycline and to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline, respectively.

Animals↗
PubMed1998

Seroprevalence of Toxoplasma gondii and Trichinella spiralis in finishing swine raised in different production systems in North Carolina, USA.

We compared the seroprevalence of both Toxoplasma gondii and Trichinella spiralis in finishing pigs raised in different production systems in North Carolina, USA. Farms were either finishing sites using all-in/all-out management of buildings in multiple-site systems (14 farms) or farrow-to-finish systems using continuous-flow management of finishing barns or outdoor accommodation 14 farms). The two groups of herds differed with respect to several management variables. A total of 13 of 2238 samples (0.58%) were positive for antibodies to Toxoplasma gondii using the modified agglutination test. Of these, 12 were from 63 pigs sampled on a farm where finishing pigs were kept on pasture. Only one of 1752 (0.057%) samples from pigs kept in total confinement systems was seropositive. Only one pig of 2183 (0.046%) tested positive by ELISA for antibodies against T. spiralis. In this region, management practices in modern production systems appear to be adequate to virtually eliminate the risk of infection of finishing pigs with both T. gondii and T. spiralis.

Animal Husbandry↗
PubMed1998

Isolation of Salmonella serotypes from feces of pigs raised in a multiple-site production system.

OBJECTIVE: To determine the prevalence and serotypes of Salmonella organisms in feces of pigs raised in a modern, multiple-site production system. DESIGN: Cross-sectional study of prevalence. SAMPLE POPULATION: Swine housed on 7 farms (1 gilt development farm, 2 breeding farms, 1 nursery farm, and 3 finishing farms) that formed a multiplesite production system. PROCEDURE: Fecal samples were obtained from 792 pigs (96 to 202/farm) and submitted for bacteriolgic culture of Salmonella organisms. RESULTS: Salmonellae were isolated from pigs on all 7 farms and from 95 of 792 (12%) fecal samples. Prevalence ranged from 3.4% at the gilt development farm to 18 and 22% at the breeding farms. Serotypes identified were Salmonella derby, S typhimurium var. copenhagen, S heidelberg, S typhimurium, S mbandaka, S worthington, and S tennessee. No single serotype was not isolated from all the farms of the production system and the most prevalent serotypes at the 3 finishing farms (S typhimurium or S typhimurium var. copenhagen) were not isolated from the breeding or nursery farms. CLINICAL IMPLICATIONS: Upstream infection (pigs infected before arriving at finishing farms) appears to be an unimportant source of Salmonella infection of finished hogs in multiple-site systems. High prevalence of Salmonella shedding in breeding animals suggests that food products derived from culled breeding livestock may be an important source of foodborne disease.

Animal Husbandry↗
PubMed1997

Epidemiologic evaluation of decubital ulcers in farrowing sows.

OBJECTIVE: To define temporal patterns and risk factors for development of decubital ulcers over the tuber of the spine of the scapula (tuber) of lactating sows. DESIGN: Prospective study. ANIMALS: 147 late-gestation sows and gilts. PROCEDURE: Females were examined for skin lesions over the tubers, and body condition score, depth of back fat, and depth of soft tissues over the tuber (tuber depth) were determined (day 0). On days 5, 12, 18, 40, 54, and 68, sows were examined for lesions over the tubers. Data on sow parity, date of farrowing, total number of pigs born/litter, and number of stillborn pigs/ litter were obtained from farm records. RESULTS: Ulcers were recorded for 33 of 206 (16%) shoulders by day 5. Peak prevalence (99/206; 48% of shoulders) was on day 12, and all ulcers had resolved by day 68. Ulcers were more common on the right shoulder. Considerable resolution of ulcers was evident between days 12 and 18, when sows still were housed in farrowing crates. Parity and tuber depth were significantly associated with ulcers and ulcer severity (size) on day 12. CLINICAL IMPLICATIONS: Decubital ulcers in lactating sows are a multifactorial condition. Factors such as floor type are important, but other physiologic and behavioral factors of periparturient swine, including body weight, body condition and mobility of late-gestation animals, duration of farrowing, and patterns of recumbency and activity, appear to be important in the pathogenesis of lesions. Housing sows on hard floors is not a sufficient cause of decubital ulcers over the scapula.

Adipose Tissue↗
PubMed1997

Risk of shedding Salmonella organisms by market-age hogs in a barn with open-flush gutters.

OBJECTIVE: To compare prevalence of fecal shedding of Salmonella organisms and serum antibodies to Salmonella sp in market-age pigs housed in barns with partially slotted floors or solid floors with open-flush gutters. DESIGN: Cross-sectional study of prevalence. SAMPLE POPULATION: Finishing-age pigs deemed by the producer to be within 1 month of slaughter. PROCEDURE: Fecal and serum samples were obtained from a group of 121 pigs housed in a barn with solid floors (31 fecal samples, 30 serum samples) and from a group of about 400 pigs housed on partially slotted floors (57 fecal samples, 64 serum samples). Fecal samples were submitted for bacteriologic culture to detect Salmonella organisms, and serum samples were tested for antibodies by use of ELISA. RESULTS: Salmonella agona was isolated from 26 of 31 (84%) fecal samples obtained from pigs housed in the open-flush gutter barn, compared with 5 of 57 (9%) fecal samples from pigs in the barn with slotted floors. Median value for optical density was higher for serum samples from pigs housed in the open-flush gutter barn. CLINICAL IMPLICATIONS: Housing of finishing-age swine in barns with open-flush gutters may contribute to increased shedding of Salmonella sp. Analysis of our observations indicated that repeated exposure to infected feces is important in prolonging fecal shedding by swine.

Animals↗
PubMed1997

Validation of a poultry biosecurity survey.

A questionnaire for farm managers was designed, to obtain information regarding biosecurity on Ontario commercial broiler chicken and turkey operations, and then pre-tested. The questions that could be validated were verifiable by seeing the facility, by using farm records or by interviewing technical personnel other than the survey respondent. The survey was validated using a convenience sample of 24 farms from two companies. For 15 questions with dichotomous responses, the sensitivity ranged from 16.7 to 100%; the specificity ranged from 0 to 100%. For example, fences and gates seen during the farm visit were not accurately reported on the survey (poor sensitivity). Chance-corrected agreement was low (kappa < 0.4) for 34 questions, fair to good (0.4 < kappa < 0.8) for 25 questions, and excellent (kappa > 0.8) for seven questions. The percent agreement for questions where only one of the possible options was observed on validation ranged from 60.9 to 100%. Five questions with continuous numeric variables were analysed. A difference was observed (P < 0.1) between the survey and validation data for three questions regarding the number of birds, the bird sources and the downtime between flocks. In spite of pre-testing, the lack of clear wording and the absence of definitions for technical terms appeared to reduce validity. Response bias seems to be an issue with biosecurity surveys. The value of validating questionnaires before their use in epidemiologic research is confirmed.

Animal Husbandry↗
PubMed1997

Prevalence of Salmonella in finishing swine raised in different production systems in North Carolina, USA.

We compared the prevalence of salmonella in faecal samples from finishing pigs and in feed samples from swine herds in North Carolina, USA. Farms were either finishing sites using all-in/all-out management of buildings in multiple-site systems (14 farms) or farrow-to-finish systems using continuous flow management of finishing barns (15 farms). The two groups of herds differed with respect to several management variables. Salmonella were isolated from 565 of 2288 (24.6%) faecal samples and from at least 1 faecal sample on 24 of 29 (83%) farms. Predominant serotypes were S. derby, S. typhimurium (including copenhagen), S. heidelberg, S. worthington and S. mbandaka. Fewer farrow-to-finish farms were detected as positive compared with all-in/all-out farms. Prevalence was lower for pigs raised on slotted floors compared with all other floor types, and was highest for pigs raised on dirt lots. Modern methods of raising pigs in multiple-site production systems, using all-in/all-out management of finishing pigs, appear to have no benefit in reducing the prevalence of salmonella compared with conventional farrow-to-finish systems.

Animal Feed↗
PubMed1997

Deaths resulting from animal attacks in the United States.

The objective of this study was to elucidate the etiology and frequency of deaths in the United States from encounters with animals. The number of deaths from venomous and nonvenomous animals is reported annually to the US Department of Health and Human Services and published in Vital Statistics of the United States. This study is a survey of all animal-related fatalities listed as E-codes 905-906 reported in the Vital Statistics of the United States from 1979 through 1990. Data were extracted uniformly from the annual reports and analyzed using descriptive statistics. From 1979 through 1990, there were 1882 animal-related deaths in the United States. Venomous animals caused 718 deaths; nonvenomous animals caused 1164 deaths. Most deaths occurred among white males. The home site was the location of injury for the majority of deaths. The majority of venomous animal-related deaths were from hymenoptera; "other specified animal" caused the majority of nonvenomous deaths. An annual average of 157 deaths from animal attacks occurred in the United States between 1979 and 1990. Both fatal and nonfatal animal-related injuries are under-recognized public health hazards. Health care providers should educate their patients on exercising caution around animals, seeking medical care after an animal injury, carrying epinephrine kits if they have a history of systemic reactions to insect stings, and wearing helmets and other protective equipment when riding or working around large animals.

Black or African American↗
PubMed1996

Epidemiologic study of decubital ulcers in sows.

OBJECTIVE: To determine prevalence and risk factors for decubital ulcers of the shoulder in sows. DESIGN: Descriptive cross-sectional study. SAMPLE POPULATION: All females of breeding age in a large confinement swine facility. PROCEDURE: 1,916 females were examined for lesions of the skin over the tuber of the spine of the scapula and for body condition scoring. Observational data were combined with sow data (parity, date of farrowing, litter size) contained in computerized records. RESULTS: Decubital ulcers were observed in 8.3% of females, predominantly lactating sows. Ulcer prevalence was strongly associated with time after farrowing. Lesions apparently healed rapidly after weaning. Ulcer prevalence was associated with low body condition scores, but was not associated with parity. IMPLICATIONS: Decubital ulcers are a multifactorial condition. Housing on concrete floors per se did not result in ulcers. Prolonged recumbency during parturition, reduced activity in early lactation, periparturient illness, thin body condition, moist skin, and floor type are potential risk factors.

Animal Nutritional Physiological Phenomena↗
PubMed1996

Efficacy of the antimicrobial compound U-82,127 as a growth promoter for growing-finishing pigs.

The antimicrobial compound U-82,127 (Pharmacia & Upjohn, Kalamazoo, MI) is a thiopeptide that belongs to a series of cyclic peptide antibiotics produced by Streptomyces arginensis. It is active mainly against Gram-positive organisms. A study involving 576 growing-finishing pigs was conducted at six locations to assess the efficacy of the growth-promoting compound from approximately 19 to 89 kg BW. The basal diet was an unmedicated corn-soybean meal diet fortified with vitamins and trace minerals and containing 16% CP (.80% lysine) during the growing stage (to 54 kg) followed by 13% CP (.60% lysine) during the finishing stage. Dietary dose concentrations of the antimicrobial compound were 0, 3.3, 6.6, and 9.9 mg/kg. At each location, there were six replications of four pigs (two barrows and two gilts) per pen. Diets and water were available for ad libitum consumption. The antimicrobial was provided in coded bags, and investigators were blind to the treatments. The ADG during the growing stage was improved by all levels of the antimicrobial (P < .04), but only the 6.6 mg/kg level improved ADG during the finishing stage (P < .03). Feed:gain was improved by all concentrations of the antibiotic (P < .01) during the growing stage and by the two lower levels of the drug (P < .06) during the finishing stage. Over the entire study, the antimicrobial compound improved ADG (linear, P < .06) and feed:gain (quadratic, P < .01; minimum feed:gain was at 6.2 mg/kg). The lowest dose with a 90% confidence interval of its predicted value not overlapping with the predicted value of the control was 2.3 mg/kg; thus, the efficacious dose range for improving feed/gain was between 2.3 and 6.2 mg/ kg. Neither death loss nor pig removal from the experiment was affected by treatment. The results indicate that the antimicrobial compound U-82,127 is an effective growth-promoting agent for growing-finishing pigs.

Animals↗
PubMed1994

A research feasibility assessment of regulatory information systems capacities for investigation of epidemiologic factors in pseudorabies.

Pseudorabies (PR) outbreak-investigation forms from 10 states having the most PR-infected herds were evaluated for agreement in question response-data type, information intent, and outbreak information categories. A question randomly selected from an investigation form had 0.6304 probability of being unique to a single state, and 0.0062 probability of being common to all states. Analysis of outbreak forms, on the basis of information intent, revealed that the probability of a randomly selected question being derived from an information category unique to a single state was 0.0323, whereas the probability of a question being derived from an information category shared by all states was 0.1935. A telephone survey revealed that state PR control officials did not believe additional research on between-herd spread of PR was necessary to successfully complete the eradication program. However, officials believed a better understanding of PR risk factors would enhance program effectiveness and build producer confidence.

Animals↗
PubMed1994

Developing an information resources management strategy for regulatory veterinary medicine: a national imperative.

Lack of a standardized information technology management strategy has resulted in state and federal information systems evolving separately, rather than in tandem. Absence of an information management strategy will eventually affect regulatory program management, epidemiologic research, and domestic and international livestock trade. Producers will ultimately pay the price for the lack of regulatory coordination of US animal health and disease information. The longer the development of state and federal information technology management strategies is postponed, the more cost-, labor-, and time-intensive correcting the deficiency will be. Development of a national information resources management environment is the first step in constructing state and federal information technology strategies.

Animal Diseases↗
PubMedDate not supplied

Euthanasia hazards.

Every day, and for many reasons, animal handlers must euthanize animals in their care. Because euthanasia results in the death of an animal and involves a lethal agent, it is inherently dangerous for operators. Euthanasia technicians must know how to control the animal and understand normal animal behavior, the effect of handling, and how the agents work. Appropriate animal control is possibly the most important step, and the degree of control necessary depends on the animal and the chosen agent. Handlers should be trained in how to administer the agents. Trainers must fully explain why the animals must be euthanized, and operators should be allowed to refuse to euthanize animals. Everyone should be trained to recognize signs of excessive exposure to or abuse of euthanasia agents and take the necessary steps should an incident occur.

Animal Technicians↗