Strategies designed to minimize the probability of bluetongue virus (BTV) introduction to new areas should be based on a quantitative assessment of the probability of actually establishing the virus once it is introduced. The risk of introducing a new strain of bluetongue virus into a region depends...

To investigate the association between genital bacterial infection and urogenital carcinoma in California sea lions (Zalophus californianus), vaginal and preputial swabs for bacterial isolation were taken from 148 free-ranging and 51 stranded California sea lions including 16 animals with urogenital...

Ranch-reared mink (Mustela vison) were used as a model in an experimental trial to investigate the potential effects of exposure to two petroleum products on sea otters (Enhydra lutris). Mink were exposed either dermally on one occasion 60 days prior to breeding or via low level contamination of the...

We present methods for binomial regression when the outcome is determined using the results of a single diagnostic test with imperfect sensitivity and specificity. We present our model, illustrate it with the analysis of real data, and provide an example of WinBUGS program code for performing such a...

The association among anthropogenic environmental disturbance, pathogen pollution and the emergence of infectious diseases in wildlife has been postulated, but not always well supported by epidemiological data. Specific evidence of coastal contamination of the marine ecosystem with the zoonotic prot...

Bivalve molluscs concentrate Cryptosporidium oocysts from fecal-contaminated aquatic environments and are therefore useful in monitoring water quality. A real-time TaqMan polymerase chain reaction (PCR) system was developed to allow for large scale quantitative detection of Cryptosporidium pp. in mu...

The coastal ecosystems of California are highly utilized by humans and animals, but the ecology of fecal bacteria at the land-sea interface is not well understood. This study evaluated the distribution of potentially pathogenic bacteria in invertebrates from linked marine, estuarine, and freshwater ...

Melengestrol acetate (MGA) contraceptives are widely used in zoo felids to regulate fertility and may have deleterious effects on endometrial health. To determine whether MGA exposure was associated with endometrial disease, the genital tracts of 212 zoo felids (99 MGA treated and 113 control) repre...

When a perfect reference test (i.e. "gold standard") is not available, it is possible to obtain estimates of test sensitivity and specificity using "latent-class" methods. However, there are few widely available software programmes that allow the implementation of these procedures. The following art...

Our objective was to estimate the sensitivity and specificity of the agar-gel-immunodiffusion test (AGID), the ELISA, and the skin test for the detection of Mycobacterium avium subspecies paratuberculosis (MAP) in sheep using Bayesian methods without a gold standard. Fourteen flocks (2 465 sheep) we...

A modified culture method using C18-carboxypropylbetaine (CB-18) and microscopic screening was evaluated for time to and limit of detection of Mycobacterium avium subsp. paratuberculosis (MAP) in raw milk. Bulk-tank milk samples were spiked with six different concentrations (101 to 106 CFU/mL) of MA...

The two-test two-population model, originally formulated by Hui and Walter, for estimation of test accuracy and prevalence estimation assumes conditionally independent tests, constant accuracy across populations and binomial sampling. The binomial assumption is incorrect if all individuals in a popu...

Certification that a country, region or state is "free" from a pathogen or has a prevalence less than a threshold value has implications for trade in animals and animal products. We develop a Bayesian model for assessment of: (i) the probability that a country is "free" of or has...

An aryl hydrocarbon (Ah) receptor-based luciferase cell culture bioassay developed to detect 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other halogenated aromatics was modified and optimized to detect and quantitate polycyclic aromatics (PAHs). Twenty-four PAHs were analyzed, and subsequent EC50...

Polycyclic and halogenated aromatic hydrocarbons (PAHs/HAHs) are a diverse group of widespread and persistent environmental contaminants that can cause a variety of detrimental effects in vertebrates. As most available methods to detect these contaminants are expensive, labor and time intensive, and...

A computer simulation study was carried out using production and reproduction data from 1642 dairy herds for 1984 to determine an optimum combination of sampling plan and sample size for obtaining precise estimates of the population and disease parameters of the California dairy cattle production. T...

Milk from 172 commercial cows with mild to moderate clinical mastitis was tested with 5 antibiotic residue detection assay systems. 100 cows were treated with 1 of 2 intramammary β-lactam antibiotics and the remaining 72 cows were treated with intramuscular oxytocin. Milk samples were collected pre...

A prospective cohort study was undertaken in a farrow-to-farrow pig herd to describe patterns of pneumonia, and to identify host risk factors associated with the extent of pneumonic lesions in 2 weight groups of slaughter swine. The risk of coughing and pneumonic lesions increased with increasing ag...

The authors evaluated existing list frames for disease surveillance by a telephone survey of 50 producers in Tulare county. No single ideal list frame existed, but the list frame of the Statistical Reporting Service, which included only 54% of the surveyed herds and 86% of the breeding swine within ...

During 1986 and 1987, mortality, morbidity, case-fatality, and culling rates were estimated for endemic disease conditions in 43 randomly selected California dairy farms. Data were collected mainly by farmer interview. Age-specific mortality rates were: calves 22.8 per 1000 calf-months at risk; youn...

For 3 California, USA, dairy herds with bulk tank somatic cell counts <200 000/ml, twice daily milking and no mastitis vaccine, 254 quarters with mild clinical mastitis were randomly assigned to 3 groups. Group A (n = 74) was treated with 62.5 mg of intramammary amoxicillin every 12 h for 3 milkings...

Two newly-born Anglo Nubian kids with clinical evidence of a severe neurological condition were examined. Pathological examination revealed extensive cytoplasmic vacuolation in neural tissue and in localized areas in the kidney, pancreas and lymphoid tissue. Biochemical investigations demonstrated a...

Sera (n = 806) from 50 populations of bighorn sheep (O. canadensis) in California, USA, were evaluated for antibodies to Psoroptes sp. mites using a kinetic ELISA. Test values for each sample were determined to be either positive or negative at each of 2 ELISA cutoff values that provided either 100%...

Blood samples were collected from 145 goats >2years of age: 60 from the University farms and 74 and 12 goats from 2 farms which had a clinical history of caseous lymphadenitis. The synergistic haemolytic inhibition (SHI) test identified 36 goats that gave a positive reaction to caseous lymphadeni...