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Objective: To estimate the analytic sensitivity of microscopic detection of Toxoplasma gondii oocysts and the environmental loading of T gondii oocysts on the basis of prevalence of shedding by owned and unowned cats., Design: Cross-sectional survey., Sample Population: 326 fecal samples from cats., Procedures: Fecal samples were collected from cat shelters, veterinary clinics, cat-owning households, and outdoor locations and tested via ZnSO(4) fecal flotation., Results: Only 3 (0.9%) samples of feces from 326 cats in the Morro Bay area of California contained T gondii-like oocysts. On the basis of the estimated tonnage of cat feces deposited outdoors in this area, the annual burden in the environment was estimated to be 94 to 4,671 oocysts/m(2) (9 to 434 oocysts/ft(2))., Conclusions and Clinical Relevance: Despite the low prevalence and short duration of T gondii oocyst shedding by cats detected in the present and former surveys, the sheer numbers of oocysts shed by cats during initial infection could lead to substantial environmental contamination. Veterinarians may wish to make cat owners aware of the potential threats to human and wildlife health posed by cats permitted to defecate outdoors.

Objective: To estimate cat population size, management, and outside fecal deposition and evaluate attitudes of cat owners and nonowners to stray animal control, water pollution, and wildlife protection., Design: Cross-sectional survey., Sample Population: 294 adult residents of Cayucos, Los Osos, and Morro Bay, Calif., Procedures: Telephone survey., Results: The region's cat population was estimated at 7,284 owned and 2,046 feral cats, and 38% of surveyed households owned a mean of 1.9 cats/household. Forty-four percent of cats defecated outside >75% of the time. Annual fecal deposition (wet weight) by owned cats in the 3 communities was estimated to be 77.6 tonnes (76.4 tons). Cat owners were more likely to oppose cat licensing and impounding stray cats and support trap-neuter-return for stray cats and less likely to be concerned about water pollution, than were noncat owners., Conclusions and Clinical Relevance: Feral cats represented a sizeable proportion (22%) of the free roaming cats in this area and could be contributing 30.0 tonnes (29.5 tons) of feces to the environment per year. However, feral cats are not the principal source of fecal loading because owned cats defecating outdoors contribute an estimated 77.6 tonnes (76.4 tons) or 72% of the annual outdoor fecal deposition.

Objective: To evaluate the effect of daily oral administration of decoquinate to neonatal calves experimentally challenged with various numbers of Cryptosporidium parvum oocysts., Design: Clinical trial., Animals: 75 calves., Procedure: Calves were purchased from a commercial dairy during a 5-week period. Calves were housed in individual hutches and fed milk replacer with or without decoquinate (2 mg/kg [0.9 mg/lb per day]). Calves were randomly assigned to treatment and 1 of 5 challenge groups (0, 50, 100, 1000, or 10,000 C. parvum oocysts in 60 mL of saline [0.9% NaCl] solution administered p.o. on the day after arrival). Calves were maintained in the study for as long as 28 days. Calves were clinically assessed for diarrhea and dehydration. Fecal samples were submitted for oocyst enumeration 3 times each week., Results: Treatment did not affect number of days to first watery feces (diarrhea), number of days to first oocyst shedding, or duration of diarrhea or oocyst shedding. Duration of oocyst shedding was significantly associated with challenge dose of oocysts administered to calves and number of days to first oocyst shedding. Duration of diarrhea and number of days to first oocyst shedding were significantly associated with week of arrival and number of days to first watery diarrhea., Conclusions and Clinical Relevance: Daily treatment with decoquinate at the dosage used in this study did not affect oocyst shedding or clinical signs associated with cryptosporidiosis. However, there was an indication that if the number of oocysts calves received could be reduced, then the duration of oocyst shedding and, hence, environmental loading of C. parvum oocysts could be reduced.

Objective: To evaluate the association of herd demographics, parturition variables, stocking rate, and rotational grazing practices with the probability of fecal shedding of Cryptosporidium parvum from beef cow-calf herds in California., Design: Cross-sectional study., Sample Population: 38 beef cow-calf operations., Procedure: Fecal specimens were collected and examined for C parvum oocysts, using immunofluorescent microscopy. Association between various demographic and management factors and the probability of shedding C parvum were statistically evaluated., Results: Adjusted for age and month of collection of a fecal sample, cattle from herds with a high number of young calves (< or = 2 months old) on the day of sample collection, a high stocking rate (No. of cattle/acre/mo), or a longer calving season were more likely to shed C parvum oocysts, compared with cattle from herds with fewer young calves, a lower stocking rate, or a shorter calving season. Cattle from herds with a higher number of older calves (> 2 months old) on the day of sample collection were less likely to shed C parvum oocysts, compared with cattle from herds with fewer older calves. Using our multivariate model, rotational grazing systems or season of onset of calving were not associated with shedding status for C parvum oocysts., Conclusions and Clinical Relevance: Reproductive management that would result in a shorter calving season and use of a lower stocking rate for cattle may be associated with reduced risk of C parvum shedding. Intensive rotational grazing systems and time of year for onset of calving season apparently have little effect on reducing prevalence of oocyst shedding.

Objective: To determine whether treatment with a commercially available nonspecific immunomodulating biologic product would alter the clinical course of disease in neonatal calves., Design: Systematically randomized, controlled cohort study., Animals: 200 Holstein bull calves 1 to 5 days old., Procedure: Assessments were performed that included evaluation of fecal consistency, attitude, appetite, and hydration status. Calves with abnormal results were enrolled in the study. Calves were systematically assigned to control or treatment groups (100 calves/group). Calves in the treatment group were given a single i.v. injection of the biologic product at the time of enrollment, whereas control calves were not given the product. Calves were assessed daily for 5 days to evaluate fecal consistency, attitude, appetite, hydration status, and rectal temperature. Assessments were made without knowledge of group assignment., Results: Treatment with the immunomodulating product was not associated with a decrease in the number of calves that had moderate or severe departures from clinically normal conditions for attitude, appetite, or hydration on days 1 though 5, compared with control calves. Fecal consistency scores were significantly greater for treated calves on days 1 (P = 0.03) and 5 (P = 0.02), compared with scores for control calves., Clinical Implications: Administration of the nonspecific immunomodulating biologic product did not significantly affect outcome of clinical disease for calves in the treated group, compared with calves in the control group. On the basis of results of this study, we cannot recommend use of the nonspecific immunomodulating biologic product for the treatment of undifferentiated diarrheal disease in neonatal calves.

Objective: To determine whether preferentially vaccinated horses were at risk for exposure to Ehrlichia risticii, whether horses with equine monocytic ehrlichiosis (EME) were likely to have been nonvaccinated, and whether clinical severity and financial costs associated with care and treatment of EME were less for vaccinated horses with EME than for nonvaccinated horses with EME., Design: Cross-sectional and case-control studies., Procedure: Information on usage of E risticii bacterins to control EME was collected for 2,587 horses located on 511 farms throughout New York. Each horse was tested for serum antibodies directed against E risticii. Data on efficacy of vaccination to reduce the prevalence and clinical severity of EME and monetary losses associated with EME were collected from 68 horses with EME and 132 clinically normal horses., Results: A correlation was not detected between the county seropositive proportion and the proportion of horses vaccinated against EME. Among horses diagnosed for EME, median date of diagnosis was not delayed for vaccinated horses, compared with that for nonvaccinated horses. Mean cost per case was not significantly different for nonvaccinated horses, compared with that for vaccinated horses ($ 1,082 and $ 1,001, respectively). Vaccination was not associated with a reduction in prevalence or in severity of EME-related clinical signs., Clinical Implications: Administering killed E risticii bacterin once a year to control EME in New York appears to have limited success. Among horses in which EME was diagnosed, severity of illness and financial costs attributable to EME were indistinguishable for vaccinated and nonvaccinated horses.

Objective: To determine whether horses in New York should be vaccinated against equine monocytic ehrlichiosis (EME)., Design: Decision-tree analyses of data from a cross-sectional study and a case-control study., Sample Population: Horses in New York., Procedure: Annual expected monetary loss per horse attributable to EME was calculated for vaccinated and nonvaccinated horses in New York. Because risk of being seropositive was dependent on county in which the horse was located, farm elevation, and use of each horse, decision-tree analyses were stratified by these factors., Results: Annual expected monetary loss per horse attributable to EME for horses vaccinated by veterinarians ranged from $ 21 to $ 21.83/horse/y; for horses vaccinated by owners ranged from $ 10 to $ 10.83/horse/y; and for nonvaccinated horses ranged from $ 0 to $ 4.03/horse/y. Assuming 78% of vaccinated horses were protected and mean losses associated with EME included costs for horses that died, annual incidence density at which expected monetary loss for vaccinated horses was equal to that for nonvaccinated horses was 12 cases/1,000 horses/y and 25 cases/1,000 horses/y for horses vaccinated by owners or by veterinarians, respectively., Clinical Implications: Annual vaccination minimizes monetary losses attributable to EME only when the annual incidence density exceeds 12 to 25 cases/1,000 horses/y. In New York, expected monetary losses are minimized when horses are not vaccinated because of the low annual incidence density in most regions.