Objective—To determine gene expression of selected molecular markers (tumor necrosis factor [TNF]-α, interleukin [IL]-1β, IL-6, IL-8, IL-10, procalcitonin [PCT], and transforming growth factor [TGF]-β) in the blood of healthy and sick foals.
Animals—28 sick foals without sepsis, 21 foals with sepsis, and 21 healthy foals.
Procedures—Total RNA was extracted from blood samples and converted into complementary DNA (cDNA). Gene expression was measured for the molecular markers by use of real-time PCR assay, and final quantitation was performed with the comparative threshold cycle method.
Results—Samples from all foals yielded transcription for all markers. Expression of TNF-α and TGF-β was significantly lower and that of IL-8 significantly greater in the sick-nonseptic and septic groups, compared with the healthy group. No significant difference in expression of IL-1β, IL-6, and PCT was found between the healthy group and the 2 sick groups. Expression of IL-10 was significantly greater in nonsurvivors, compared with survivors.
Conclusions and Clinical Relevance—The cytokine profile in foals with sepsis may suggest an immunosuppressive state. Expression of IL-10 may be a marker for identification of foals with a guarded prognosis.
Objective—To determine susceptibility of cattle to
infection with Ehrlichia equi and the agent of human
granulocytic ehrlichiosis (HGE).
Design—Experimental disease and prevalence survey.
Animals—6 cattle, 2 horses, and 2,725 serum samples
from healthy cattle.
Procedure—2 cattle and 1 horse were inoculated
with E equi, 2 cattle and 1 horse were inoculated with
the HGE agent, and 2 cattle served as sham-inoculated
controls; inoculated animals were evaluated via
clinical, hematologic, serologic, and real-time polymerase
chain reaction tests. Prevalence of antibodies
against E equi in 2,725 healthy cattle was determined
by use of an indirect immunofluorescent technique.
Results—No abnormal clinical or hematologic findings
or inclusion bodies within granulocytes were
observed in the cattle after inoculation, and results of
all polymerase chain reaction tests were negative.
Seroconversion in inoculated cattle developed 10 to
12 days after inoculation (reciprocal titers, 160). Both
horses developed clinical signs of ehrlichiosis. Five of
2,725 (0.18%) cattle were seropositive for E equi,
with titers ranging from 20 to 80. All seropositive cattle
originated from the same tick-rich region in the
Sierra Nevada foothills.
Conclusions and Clinical Relevance—Results suggest
that cattle are not susceptible to infection with E
equi or the agent of HGE and that prevalence of exposure
to E equi in healthy cattle is low. Therefore, E
equi and the agent of HGE are likely of negligible
importance for cattle in North America. (J Am Vet Med
Objective—To evaluate the effectiveness of a commercial conventional blood culture system (BCS), a commercial resin-containing BCS, and a commercial lysis-centrifugation–based BCS for the recovery of Escherichia coli from equine blood samples inoculated with that organism.
Sample Population—Samples of blood obtained from a clinically normal horse that were inoculated with E coli.
Procedures—Blood samples were aseptically collected and inoculated with an E coli specimen (50 CFUs/mL) that had been previously isolated from a foal with sepsis. Subsequently, samples were spiked with gentamicin at a concentration of 30 μg/mL, and 10 mL of each mixture was inoculated into 1 bottle or tube of each BCS. Samples were processed and incubated according to the manufacturer's guidelines and inoculated onto 5% sheep blood agar plates. Plated samples were examined macroscopically at regular intervals for as long as 72 hours. Detection of E coli and time to detection were recorded for each medium.
Results—Detection frequency of E coli was significantly greater by use of the resin-containing BCS (14/23 bottles) than that achieved by use of the conventional BCS (7/23 bottles) or the lysis-centrifugation–based BCS (0/10 tubes). Mean detection time (6 hours after plating) did not differ between the BCS with conventional medium and the BCS with resincontaining medium.
Conclusions and Clinical Relevance—Results suggest that a BCS with resin-containing medium may provide clinical benefit in the successful recovery of E coli from the blood of foals with sepsis that have been previously administered gentamicin.
OBJECTIVE To describe the general seroprevalence of anti-Sarcocystis neurona and anti-Neospora hughesi antibodies among healthy equids by use of indirect fluorescent antibody tests and determine potential risk factors for seropositivity.
DESIGN Cross-sectional study.
SAMPLE Whole blood samples collected from 5,250 equids (1 sample/animal) across 18 states in the United States during October 2013.
PROCEDURES Information regarding potential risk factors (geographic region, breed, primary use, sex, and age) was collected along with the blood samples. For each equid, an indirect fluorescent antibody test was used to determine serum titers of antibody against each of the 2 protozoal parasites. Mixed-effects logistic regression models were created to determine ORs for seropositivity.
RESULTS The overall seroprevalence of anti-S neurona and anti-N hughesi antibodies in the tested equids was 78% and 34%, respectively. Of the equids, 31% were seropositive and 18% were seronegative for antibodies against both parasites. Factors associated with equids being seropositive for anti-S neurona antibodies were residence in the South, warmblood breed, and age > 5 years. Seroprevalence of anti-N hughesi antibodies did not differ among equids in different states across the country, but warmblood breed and age > 5 years were associated with seropositivity.
CONCLUSIONS AND CLINICAL RELEVANCE With regard to risk factors for S neurona and N hughesi exposure and antibody response among tested equids, older age was not unexpected; however, the influences of warmblood breed and geographic location on seropositivity for anti-S neurona antibody but not for anti-N hughesi antibody deserve further investigation.
Objective—To assess the serial use of serum immunoperoxidase monolayer assays (IPMAs) and fecal PCR assays, combined with other diagnostic methods, to identify subclinical Lawsonia intracellularis infections for targeted treatment of Thoroughbred foals and weanlings at farms in which the pathogen was endemic or nonendemic.
Animals—100 foals and weanlings (53 and 47 at farms in which L intracellularis was endemic and nonendemic, respectively).
Procedures—Serum was collected every 4 weeks and tested via IPMA, for antibodies against L intracellularis. Fecal samples were collected every 2 weeks and tested by use of an L intracellularis–specific PCR assay. When results for IPMAs or PCR assays were positive or clinical signs compatible with equine proliferative enteropathy (EPE) were detected, clinicopathologic testing was performed to determine treatment.
Results—No foals had positive results for the L intracellularis–specific IPMA until after weaning; 32 of 53 (60.4%) weanlings at the farm in which L intracellularis was endemic and 8 of 47 (170%) at the farm in which L intracellularis was nonendemic had positive IPMA results, whereas the number of weanlings that tested positive via fecal PCR assays at those farms was 6 and 0, respectively. Nineteen of 32 weanlings with positive IPMA results at the farm in which L intracellularis was endemic were treated for EPE; 5 of these had clinical signs of EPE. No weanlings at the nonendemic farm had clinical signs of or were treated for EPE.
Conclusions and Clinical Relevance—IPMA appeared to be a useful means of identifying weanlings exposed to L intracellularis.
Objective—To characterize signalment, clinical and laboratory findings, treatment, and outcome in horses with rattlesnake envenomation in northern California.
Design—Retrospective case series.
Animals—58 client-owned horses evaluated for rattlesnake envenomation at 2 referral hospitals from 1992 to 2009.
Procedures—Records of horses with rattlesnake envenomation were reviewed, and data concerning signalment, clinical and laboratory findings, treatment, and outcome were collected. In addition, a rattlesnake-bite severity score (RBSS) was assigned to each horse. Variables were compared between horses that survived and those that did not.
Results—The overall mortality rate was 9%. Nine horses received antivenin; no complications were reported and none of the 9 died. The most common laboratory findings associated with severity of envenomation were thrombocytopenia, hypoproteinemia, hyperlactatemia, and a high RBSS.
Conclusions and Clinical Relevance—Most horses in this study had a good prognosis after being bitten by rattlesnakes. Laboratory and clinical examination findings may be useful for identifying horses with a poorer prognosis. Treatment with antivenin may be beneficial and warrants further evaluation.
Objective—To estimate likelihood ratios (LRs) of correctly identifying internal Corynebacterium pseudotuberculosis infection in horses by measurement of antibody titers via serum synergistic hemolysis inhibition (SHI) testing.
Design—Retrospective case-control study.
Animals—170 horses (171 records; 92 cases of C pseudotuberculosis infection and 79 controls).
Procedures—Medical records were reviewed, and horses were grouped on the basis of evidence of internal or external C pseudotuberculosis infection. The LRs and 95% confidence intervals for identification of internal C pseudotuberculosis infection by use of SHI test results were estimated.
Results—LRs for C pseudotuberculosis infection increased as antibody titers increased when all horses were included in analyses; LRs for detecting internal infection were significantly > 1 (null value) for reciprocal antibody titers ≥ 1,280 overall and > 160 when horses with external abscesses were excluded. Likelihood ratios for detecting internal infection did not differ from 1 (indicating no change in pretest-to-posttest odds of internal infection) when only horses with external C pseudotuberculosis infection (horses with external and internal abscesses vs those with external abscesses only) were included. The LR for detecting internal infection was 2.98 (95% confidence interval, 2.19 to 4.05) for horses with titers ≥ 512.
Conclusions and Clinical Relevance—In the study population, higher titers were typically more indicative of active external or internal C pseudotuberculosis infection than of internal disease specifically. The SHI test was not a useful predictor of internal C pseudotuberculosis infection in horses with external abscesses but was useful in the absence of external disease.
Objective—To determine gene transcription for cytokines in nucleated cells in CSF of horses without neurologic signs or with cervical stenotic myelopathy (CSM), West Nile virus (WNV) encephalitis, equine protozoal myeloencephalitis (EPM), or spinal cord trauma.
Animals—41 horses (no neurologic signs [n = 12], CSM , WNV encephalitis , EPM , and spinal cord trauma ).
Procedures—Total RNA was extracted from nucleated cells and converted into cDNA. Gene expression was measured by use of real-time PCR assay and final quantitation via the comparative threshold cycle method.
Results—Cytokine genes expressed by nucleated cells of horses without neurologic signs comprised a balance between proinflammatory tumor necrosis factor-α (TNF-α), anti-inflammatory cytokines (interleukin [IL]-10 and transforming growth factor [TGF]-β), and Th1 mediators (interferon [IFN]-γ). Cells of horses with CSM mainly expressed genes for TNF-α, TGF-β, and IL-10. Cells of horses with WNV encephalitis mainly expressed genes for IL-6 and TGF-β. Cells of horses with EPM mainly had expression of genes for IL-6, IL-8, IL-10, TNF-α, IFN-γ, and TGF-β. Cells from horses with spinal cord trauma had expression mainly for IL-6; IFN-γ; TGF-β; and less frequently, IL-2, IL-10, and TNF-α. Interleukin-8 gene expression was only detected in CSF of horses with infectious diseases.
Conclusions and Clinical Relevance—Despite the small number of CSF samples for each group, results suggest distinct gene signatures expressed by nucleated cells in the CSF of horses without neurologic signs versus horses with inflammatory or traumatic neurologic disorders.
Objective—To describe clinical manifestations of
cutaneous and ocular habronemiasis in horses and
evaluate outcome of treatment.
Procedure—The diagnosis was made on the basis of
history, clinical signs, and identification of calcified
concretions (sulfur granules) in lesions. Histologic
examination of biopsy specimens was used to confirm
the diagnosis. Case horses were compared with
a control population of 12,720 horses examined during
the same period.
Results—Arabians, gray horses, and horses with
diluted coat colors were overrepresented;
Thoroughbreds were underrepresented. Lesions
were identified most often during the summer and
early fall. The medial canthus of the eye, male genitalia,
third eyelid, and distal portions of the extremities
were the most commonly affected locations.
Twenty-five lesions were biopsied, and results of histologic
examination were consistent with a diagnosis
of habronemiasis. However, nematode larvae were
seen in only 11 (44%) biopsy specimens. Treatment
consisted of surgical removal (7 horses) or medical
treatment (56) consisting of debulking granulation tissue
and topical, intralesional, or systemic treatment
with corticosteroids. All horses were treated with
Conclusions and Clinical Relevance—Results suggest
that cutaneous and ocular habronemiasis should
be considered when examining a horse during the
summer months with a proliferative, moist, granulomatous
lesion. Treatment should be aimed at
decreasing the size of the lesion, reducing inflammation,
and preventing recurrence. In general, the prognosis
was good, and healing occurred within a few
weeks. Fly control and regular deworming with ivermectin
are recommended to reduce the incidence of
habronemiasis. (J Am Vet Med Assoc 2003;222: