Objective—To investigate risk factors for development
of equine protozoal myeloencephalitis (EPM) in
Animals—251 horses admitted to The Ohio State
University Veterinary Teaching Hospital from 1992 to
Procedure—On the basis of clinical signs of neurologic
disease and detection of antibody to Sarcocystis
neurona or S neurona DNA in cerebrospinal fluid, a
diagnosis of EPM was made for 251 horses. Two contemporaneous
series of control horses were selected
from horses admitted to the hospital. One control
series (n = 225) consisted of horses with diseases of
the neurologic system other than EPM (neurologic
control horses), and the other consisted of 251 horses
admitted for reasons other than nervous system
diseases (nonneurologic control horses). Data were
obtained from hospital records and telephone conversations.
Risk factors associated with disease status
were analyzed, using multivariable logistic regression.
Results—Horses ranged from 1 day to 30 years old
(mean ± SD, 5.7 ± 5.2 years). Risk factors associated
with an increased risk of developing EPM included
age, season of admission, prior diagnosis of EPM on
the premises, opossums on premises, health events
prior to admission, and racing or showing as a primary
use. Factors associated with a reduced risk of
developing EPM included protection of feed from
wildlife and proximity of a creek or river to the premises
where the horse resided.
Conclusions and Clinical Relevance—Development
of EPM was associated with a number of management-related factors that can be altered to decrease
the risk for the disease. (J Am Vet Med Assoc
Objective—To assess the impacts of the introduction of foot-and-mouth disease (FMD) and various FMD control programs in southern Thailand.
Animals—A native population of 562,910 cattle and 33,088 buffalo as well as 89,294 animals legally transported into southern Thailand.
Procedures—A quantitative risk assessment was used to ascertain the probability of FMD introduction, and an intrinsic dynamic model was used to assess impacts. Value for the transmission rate (β) was estimated. Five scenarios created to assess the impacts of nonstructural protein (NSP) testing, mass vaccination, and culling were examined. Impacts were assessed through an examination of the estimated annual cumulative incidence (ACI) of FMD. The ACIs of various scenarios were compared by use of the Tukey Studentized range technique.
Results—β was estimated at 0.115. Approximately 35,000 cases of FMD would be expected from the baseline situation. A 30% reduction of ACI was detected with the introduction of NSP antibody testing. Prophylactic vaccination resulted in an 85% reduction of ACI. Concurrent use of NSP antibody testing and vaccination reduced the ACI by 96%, and the addition of an eradication policy resulted in a slightly greater decrease in the ACI (98%).
Conclusions and Clinical Relevance—The study used epidemiologic models to investigate FMD control interventions. Results suggested that vaccination has more impact than the use of NSP testing. Use of the NSP test reduced ACI during peak seasons, whereas vaccination diminished the underlying incidence. The best mitigation plan was an integrated and strategic use of multiple control techniques.
Objective—To assess the likelihood of an introduction of foot-and-mouth disease (FMD) into the Malaysia-Thailand-Myanmar (MTM) peninsula through terrestrial movement of livestock.
Animals—89,294 cattle and buffalo legally moved into the MTM peninsula.
Procedures—A quantitative risk assessment was conducted by use of a stochastic simulation. Patterns of livestock movement were ascertained through review of relevant governmental records and regulations and by interviewing farmers, traders, and local officers when the records did not exist. Parameters identified in the process were the probabilities of livestock having FMD and of FMD infection going undetected during import processes. The probability of an animal accepted for import having FMD was also assessed. Sensitivity analysis was performed to determine the effects that each parameter had on the model.
Results—The simulation yielded an average consignment prevalence of 10.95%. Typically, each animal in a quarantine facility had a 2.7% chance of having an inapparent form of FMD infection; hence, it was likely an animal would not be identified as infected. Findings revealed that the mean probability of an animal accepted for import having FMD was 2.9%, and the risk was as high as 11%.
Conclusions and Clinical Relevance—Results of the model allowed for the evaluation of movement regulations currently imposed in the MTM peninsula. Evidence from the study suggested that current practices in animal movement were far from efficient in preventing introduction of FMD-infected animals into the MTM region, and additional measures will be necessary.
Objective—To determine outcome of equids in the
western United States with clinical signs of West Nile
virus (WNV) infection and identify factors associated
with risk of death in infected equids.
Animals—484 equids in Nebraska and Colorado.
Procedure—Owners of 484 equids with laboratoryconfirmed
West Nile virus infection in Nebraska and
Colorado were contacted by telephone, and a questionnaire
was used to obtain information on signalment,
management, clinical signs, date of disease
onset, duration of disease, WNV vaccination status,
and health status at the time of the interview.
Results—137 of 482 (28.4%) animals died or were
euthanatized. Ataxia, lethargy, muscle fasciculations,
and weakness were the most common clinical signs
of disease. Animals ≥ 3 years old were more likely to
die than were animals ≤ 2 years old. Unvaccinated
equids were twice as likely to die as were animals
that had been vaccinated at least once prior to the
onset of disease. Animals that were recumbent and
unable to rise were 78 times as likely to die as were
animals that never lost the ability to rise. Females
were 2.9 times as likely to die as males. Two hundred
seventy-one of 339 (79.9%) animals that survived
recovered fully; mean duration of disease for these
animals was 22.3 days.
Conclusions and Clinical Relevance—Among equids
with WNV infection, age, vaccination status, an inability
to rise, and sex were associated with the risk of
death. (J Am Vet Med Assoc 2004;225:267–274)
Objective—To investigate risk factors for use in predicting
clinical improvement and survival of horses
with equine protozoal myeloencephalitis (EPM).
Design—Longitudinal epidemiologic study.
Animals—251 horses with EPM.
Procedure—Between 1992 and 1995, 251 horses
with EPM were admitted to our facility. A diagnosis of
EPM was made on the basis of neurologic abnormalities
and detection of antibody to Sarcocystis neurona
or S neurona DNA in CSF. Data were obtained from
hospital records and through telephone follow-up
interviews. Factors associated with clinical improvement
and survival were analyzed, using multivariable
Results—The likelihood of clinical improvement after
diagnosis of EPM was lower in horses used for breeding
and pleasure activities. Treatment for EPM
increased the probability that a horse would have clinical
improvement. The likelihood of survival among
horses with EPM was lower among horses with more
severe clinical signs and higher among horses that
improved after EPM was diagnosed.
Conclusions and Clinical Relevance—Treatment of
horses with EPM is indicated in most situations; however,
severity of clinical signs should be taken into
consideration when making treatment decisions.
Response to treatment is an important indicator of
survival. (J Am Vet Med Assoc 2000;217:1181–1185)
Objective—To evaluate bacterial and protozoal contamination of commercially available raw meat diets for dogs.
Design—Prospective longitudinal study.
Sample Population—240 samples from 20 raw meat diets for dogs (containing beef, lamb, chicken, or turkey), 24 samples from 2 dry dog foods, and 24 samples from 2 canned dog foods.
Procedure—Each product was purchased commercially on 4 dates approximately 2 months apart. Three samples from each product at each sampling period were evaluated via bacterial culture for non–type-specific Escherichia coli (NTSEC), Salmonella enterica, and Campylobacter spp. Antimicrobial susceptibility testing was performed on selected isolates. Polymerase chain reaction assays were used to detect DNA from Cryptosporidium spp, Neospora spp, and Toxoplasma spp in samples obtained in the third and fourth sampling periods.
Results—One hundred fifty-three of 288 (53%) samples were contaminated with NTSEC. Both raw and prepared foods contained NTSEC during at least 1 culture period. Salmonella enterica was recovered from 17 (5.9%) samples, all of which were raw meat products. Campylobacter spp was not isolated from any samples. In 91 of 288 (31.6%) samples, there was no gram-negative bacterial growth before enrichment and in 48 of 288 (16.7%) samples, there was no aerobic bacterial growth before enrichment. Susceptibility phenotypes were variable. Cryptosporidium spp DNA was detected in 3 samples.
Conclusions and Clinical Relevance—Bacterial contamination is common in commercially available raw meat diets, suggesting that there is a risk of foodborne illness in dogs fed these diets as well possible risk for humans associated with the dogs or their environments.
Objective—To evaluate the ability of orally administered
aspirin to mitigate 3-methylindole (3MI)-induced
respiratory tract disease and reduced rate of gain in
Animals—244 beef cattle.
Procedure—In a masked, randomized, controlled
field trial, calves were untreated (controls) or received
a single orally administered dose of aspirin (31.2 g) on
entry into a feedlot. Serum 3MI concentrations were
measured on days 0, 3, and 6. Rumen 3MI concentration
was measured on day 3. Cattle were observed
daily for clinical signs of respiratory tract disease.
Lungs were evaluated at slaughter for gross pulmonary
Results—Mean daily gain (MDG) in cattle treated
with aspirin, compared with control cattle, was 0.06
kg greater in the backgrounding unit and 0.03 kg
greater for the overall feeding period. Neither serum
nor rumen 3MI concentrations appeared to modify
this effect. Cattle treated with aspirin were more likely
to be treated for respiratory tract disease.
Mortality rate, gross pulmonary lesions, and serum
and rumen 3MI concentrations were similar between
groups. Increased rumen 3MI concentration was
associated with a small difference in risk of lung
Conclusions and Clinical Relevance—Cattle given a
single orally administered dose of aspirin on feedlot
entry had higher MDG in the backgrounding unit and
for the overall feeding period, but this finding could
not be attributed to mitigation of effects of 3MI. This
may have been influenced by low peak 3MI production
and slow rates of gain. (Am J Vet Res
Objective—To determine whether immunity against
bovine respiratory syncytial virus (BRSV) mitigates the
effects of 3-methylindole (3MI) on occurrence of
bovine respiratory tract disease (BRD) and rate of gain
in feedlot cattle.
Animals—254 mixed-breed beef cattle.
Procedure—Cattle were randomly assigned to 1 of 3
groups at the time of arrival at the feedlot. One group
was vaccinated with an inactivated BRSV vaccine,
another was vaccinated with a modified-live BRSV
vaccine, and the third was maintained as unvaccinated
control cattle. On days 0 and 28, serum BRSV antibody
concentrations were measured, using serum
neutralizing and ELISA techniques. Serum 3MI concentrations
were measured at feedlot arrival and 3
days later. Cattle were monitored for development of
BRD. At slaughter, lungs were evaluated grossly for
Results—Higher serum 3MI concentrations early in
the feeding period were associated with lower mean
daily gain. Control cattle were more likely to be treated
for BRD after day 3, compared with cattle vaccinated
with the modified-live BRSV vaccine. Humoral immunity
against BRSV did not appear to modify the effect of
3MI on development of BRD or mean daily gain.
Conclusions and Clinical Relevance—Results suggest
that abrogating the effects of 3MI and BRSV
infection may improve the health and growth performance
of feedlot cattle. However, in this study, immunity
against BRSV did not appear to protect against
the potential synergism between 3MI and BRSV
infection, possibly because of the slow rates of gain
of cattle included in the study or timing of sample collection.
(Am J Vet Res 2000;61:1309–1314)
Objective—To determine whether exercise-induced
pulmonary hemorrhage (EIPH) was associated with racing
performance in Thoroughbred horses not medicated
with furosemide and not using nasal dilator strips.
Design—Observational cross-sectional study.
Animals—744 two- to 10-year-old Thoroughbred horses
racing in Melbourne, Australia.
Procedure—Horses were enrolled prior to racing, and
a tracheobronchoscopic examination was performed
after 1 race. Examinations were recorded on videotape,
and presence and severity (grade 0 to 4) of EIPH
were subsequently determined by 3 observers blinded
to the horses' identity. Race records were
abstracted for each horse examined.
Results—Overall, 52.1% of horses eligible for participation
in the study were examined, and horses that were
examined did not differ from horses that were not examined
in regard to age, sex distribution, or proportion of
horses that won or finished in the first 3 positions.
Horses with EIPH grades ≤ 1 were 4.0 times as likely to
win, 1.8 times as likely to finish in the first 3 positions,
and 3.03 times as likely to be in the 90th percentile or
higher for race earnings as were horses with grades ≥ 2.
Horses with EIPH grades ≥ 1 finished significantly farther
behind the winner than did horses without EIPH.
However, odds that horses with grade 1 EIPH would win
or finish in the first 3 positions were not significantly different
from odds for horses without EIPH.
Conclusions and Clinical Relevance—Results suggest
that EIPH is associated with impaired performance
in Thoroughbred racehorses not medicated with
furosemide and not using nasal dilator strips. ( J Am Vet
Med Assoc 2005;227:768–774)
Objective—To determine the interobserver variability
of assessment of exercise-induced pulmonary hemorrhage
(EIPH) during tracheobronchoscopic examination
Animals—747 Thoroughbred racehorses.
Procedure—850 tracheobronchoscopic examinations
were performed within 2 hours of racing for the
horses. Examinations were recorded on videotape,
and EIPH and its severity were assessed independently
by 3 veterinarians. Concordance was determined
by calculation of the Cohen weighted κ statistic
and tabulation of scores assigned by each observer.
Results—Weighted κ statistics ranged from 0.75 to
0.80. In 99.4% of observations, all observers agreed
or 2 of 3 agreed and the third differed by ≤ 1 grade.
Conclusions and Clinical Relevance—Results indicated
that interobserver reliability of tracheobronchoscopic
assessment of EIPH in Thoroughbred racehorses
is high when the examination is conducted by
experienced veterinarians. Concordance among
investigators is sufficient to justify use of this grading
system for further studies and clinical descriptions of
EIPH. (Am J Vet Res 2005;66:596–598)