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Biomedical subjects

B J Weigler

Publications and source records attributed to B J Weigler.

29 records · Page 2Linked to original sources
PubMed1993

Epidemiology of cercopithecine herpesvirus 1 (B virus) infection and shedding in a large breeding cohort of rhesus macaques.

The epidemiology of B virus infection in a large (n = 157) cohort of rhesus macaques at the California Regional Primate Research Center was evaluated prospectively from September 1989 through January 1991 by serial physical examinations, a behavioral substudy (n = 51), and repeated diagnostic testing. Half were B virus antibody-positive at baseline; subsequently, incident cases of infection were documented through serology alone (42) or with virus isolation (5). Eight recurrent infections and a single symptomatic (primary) case were observed. Risk of B virus infection increased as monkeys aged, with few > 3 years old remaining uninfected. Postpubertal monkeys and those entering sexual adolescence (2-3 years) were at greatest risk, although wounding by cagemates and breeding history (for females) were both significant predictors of time to infection. B virus was isolated from oral or conjunctival and genital tissues in equal proportions. Transmission occurred only during the breeding season, possibly coinciding with an elevation in social stressors in the population.

Animals↗
PubMed1992

Biology of B virus in macaque and human hosts: a review.

B virus is a zoonotic alpha-herpesvirus enzootic in Asian monkeys of the genus Macaca. At least 25 cases of human disease caused by B virus have occurred to date, leading to death in 16 instances. Advances in the technology available for the diagnosis of B virus infection and in the agents for its treatment are improving the prognosis for cases in human beings. Efforts are under way at several institutions in the United States to establish B virus-free colonies of rhesus macaques for use in biomedical research. Unfortunately, the epidemiology of B virus in group-housed macaques is poorly understood. The elucidation of factors important in the transmission of B virus between monkeys will greatly enhance efforts to eradicate this virus and may help to minimize further human exposure to the agent.

Animals↗
PubMed1991

Expenditures for veterinary services and other costs of disease and disease prevention in 57 California beef herds in the National Animal Health Monitoring System (1988-1989).

Data on costs associated with episodes of disease and disease prevention, including expenditures for veterinary services, were collected from 57 California beef cow-calf herds during 1988-1989 as part of the National Animal Health Monitoring System. Mean cost associated with episodes of disease was $33.90/cow-year, with $0.78 and $1.37/cow-year being spent for veterinary services and drugs, respectively. The highest cost for veterinary services related to episodes of disease were for dystocia, lameness, and ocular carcinoma. For disease prevention, mean expenditures for veterinary services were $1.67/cow-year, nearly all of which was spent on prevention of reproductive tract conditions. Preventive expenditures for veterinary services related to female infertility (pregnancy examination), vaccination against brucellosis and male infertility (breeding soundness examination) were $0.72, $0.39, and $0.22/cow-year, respectively. Many costs associated with episodes of disease and disease prevention were similar to those reported from Colorado National Animal Health Monitoring System beef herds.

Agriculture↗
PubMed1990

Veterinary and nonveterinary costs of disease in 29 California dairies participating in the National Animal Health Monitoring System from 1988 to 1989.

Twenty-nine California dairy herds were studied over a 12-month period from 1988 to 1989 as part of the National Animal Health Monitoring System. Monthly interviews administered to dairy producers were used to measure the costs of all health-related expenditures and disease incidence in these herds. Of the total $1,523,558 reported, $1,355,467 (89%) was attributed to cost of disease events and $168,091 (11%) to cost of disease prevention. Most (78%) of the cost of disease events was attributable to death and culling losses. Veterinary services accounted for only $54,099 (4%) of total costs, 64% of which was used for disease prevention, compared with 36% for disease treatment. Udder disease was the most costly category of diseases reported at an average of $49.85/head at risk annually, followed by reproductive problems at $38.05. Through the use of sampling strategies less biased than those used in other surveys, the National Animal Health Monitoring System is designed to provide statistically-valid estimates of disease incidence and costs across broad geographic areas, potentially benefiting all those interested in the economics of livestock diseases in the United States.

Animals↗
PubMed1990

Prevalence of trichomoniasis among California beef herds.

Sixty cow-half herds of more than 50 cows each were randomly selected for a prevalence survey of bovine trichomoniasis in California. Herd size, as judged by the number of bulls, ranged from 1 to 210 bulls (median = 8; mean = 59 +/- 15.8). Preputial smegma was collected from 729 bulls (median = 6 bulls/herd) and cultured for Tritrichomonas foetus. Of 57 herds from which samples were collected, 9 (15.8%) had at least one infected bull. Of the 729 bulls from which samples were cultured, 30 (4.1%) were infected. Correcting for sensitivity of the diagnostic test yielded a prevalence of 5.0%. Infection rates for bulls greater than 3 years old and less than or equal to 3 years old were 6.7% and 2.0%, respectively (P less than 0.025). Median herd sizes were 14 bulls (range, 6 to 114) for infected herds and 7 (range, 1 to 210) for uninfected herds. These findings suggest that trichomoniasis is common in California beef herds. Because several bulls less than 4 years old were infected, we suggest that control measures stressing replacement of older bulls with younger ones should be combined with diagnostic procedures in those younger replacements, to ensure that they are not already infected.

Age Factors↗
PubMed1990

A cross sectional survey for B virus antibody in a colony of group housed rhesus macaques.

A systematic sampling technique was used in combination with a highly sensitive and specific ELISA to provide unbiased age-specific prevalence estimates of B virus antibody in rhesus monkeys housed in three different outdoor breeding corrals. Among 146 sampled monkeys, 97% of animals 2.5 years and older were seropositive, while only 22% of younger animals were seropositive. Neither gender nor social dominance ranking were predictive of B virus antibody status. The strong age association was not inconsistent with hypothesized venereal transmission of B virus. Improvements in the epidemiologic understanding of B virus are necessary to assist efforts to eradicate this agent from breeding colonies of rhesus monkeys.

Age Factors↗
PubMed1989

Detection of Chlamydia psittaci in free-ranging koalas (Phascolarctos cinereus): DNA hybridization and immuno-slot blot analyses.

DNA-slot hybridization and immuno-slot blot analyses were compared for the detection of Chlamydia psittaci in crude swab material from free-ranging koalas. Immuno-slot blot analysis detected chlamydiae in 43 out of 68 koalas, with the sensitivity of the assay varying from 52 to 73% depending on the site of infection. Gene probe analysis was also used employing a genus-specific probe pCKO-10 isolated from a koala chlamydial gene library (ocular strain) and a plasmid probe pCKU cloned from a urogenital strain. The sensitivity of these two assays was comparable and they were considerably more efficient than the immuno-slot blot method for the detection of chlamydiae. Comparison of these data with a cell-culture method of detection, previously used with the same samples, demonstrated that gene probe analysis detected more positives than observed with cell culture. However, this appears to reflect more on the condition of the swab material rather than the sensitivity of the method.

Animals↗
PubMed1988

Evaluation of an enzyme immunoassay test for the diagnosis of Chlamydia psittaci infection in free-ranging koalas (Phascolarctos cinereus) in southeastern Queensland, Australia.

The IDEIA Chlamydia Test, a commercially available antigen-capture enzyme-linked immunosorbent assay (ELISA) test, based on a monoclonal antibody for the detection of chlamydia in clinical specimens, was evaluated in a population of 65 free-ranging koalas in southeastern Queensland determined to be infected with Chlamydia psittaci. Compared to isolation of the organism in tissue culture, the sensitivity of the IDEIA test ranged from 3 to 11%, and the specificity from 90 to 97%. The results indicated that the IDEIA test is unsuitable for use as a diagnostic screening test for C. psittaci in free-ranging koalas.

Animals↗
PubMed1988

Aspects of the epidemiology of Chlamydia psittaci infection in a population of koalas (Phascolarctos cinereus) in southeastern Queensland, Australia.

A population of free-ranging koalas in southeastern Queensland was examined to determine the prevalence of Chlamydia psittaci infections. Although C. psittaci was isolated from 46 of 65 (71%) koalas studied, only six (9%) of these had clinical signs of disease. Most adult females (82%) had back or pouch young present even though 67% of them were infected. There were no significant correlations between age, sex or site of sampling (urogenital versus conjunctival tissues) and the isolation of C. psittaci. No other important bacterial or fungal pathogens were isolated. The complement fixation test had a sensitivity of 7% and a specificity of 94% in detecting chlamydial infections, suggesting that it is unsuitable for use as a screening test. Chlamydia psittaci infection within this population appeared to represent a generally well-balanced host-parasite relationship and few animals had clinical signs of disease. Only four of 27 (15%) healthy koalas infected with C. psittaci followed for 24 wk after sampling developed eye disease or "dirty tail." Two koalas with keratoconjunctivitis recovered without treatment during the study period. Additional factors, including the stresses imposed by loss of habitat, may act to produce overt disease in koalas with latent C. psittaci infections.

Animals↗
PubMedDate not supplied

Evaluation of biosecurity in broiler breeders.

The economic impact of management practices designed to limit the introduction of disease into a parent broiler breeder flock (biosecurity) was evaluated using benefit-cost analysis. Equations were developed to quantify the losses resulting from infection with one of four alternative categories of disease representing incremental levels of pathogenicity. Realistic costs and assumed values relating to the probability of infection were used to evaluate the ameliorative effect of three alternative levels of biosecurity. A microcomputer spreadsheet program was used to confirm that expenditure on protective measures can be justified by both the risk of introducing a disease and the magnitude of losses that may occur following infection.

Animal Husbandry↗