CS 2013-2018 Flashcards
3 main general approaches that have been
recommended for limiting AMR:
preventing disease occurrence
reducing overall antimicrobial drug use
improved antimicrobial drug use
Examples of appropriate compounding in veterinary practice
mixing 2 approved drugs
preparing an oral paste or suspension from crushed tablets
adding flavoring to an approved drug
TB horses with epistaxis or EIPH grade __ have shortened careers
4
How does EIPH affect race performance
increases the likelihood of poor finish position or finishing further behind the winner
How does furosemide affect horses with EIPH?
There is high quality evidence that furosemide (0.5–1 mg/kg administered IV 4 hours before strenuous exercise) decreases the severity and incidence of EIPH.
**reduces pulmonary vascular pressure
**is associated with improved performance by TB and StB racehorses.
general all encompassing term to describe erosive and
ulcerative diseases of the stomach
Equine Gastric Ulcer Syndrome
EGUS
occurs in animals with delayed gastric outflow secondary to an underlying abnormality such as pyloric stenosis
secondary ESGD
The highest prevalence of ESGD occurs in
Thoroughbred racehorses
Horses that are rarely competed and predominantly used in their home environment have the lowest ESGD prevalence
The majority of EGGD lesions are found
within the pyloric antrum.
Asthma - Mild or Severe?
Signs are chronic (at least 4 weeks in
duration)
Mild / IAD
Asthma - Mild or Severe?
Signs and severity may vary over time, often
limiting activity
Severe
Asthma - Mild or Severe?
Often improve spontaneously or with
treatment. Risk of recurrence low
Mild / IAD
Asthma - Mild or Severe?
Excess mucus in tracheobronchial tree
(score >1 for racehorses and >2
for sports/pleasure horses).
Mild / IAD
BALF eosinophilia is more commonly
encountered in
young horses <5
BALF neutrophilia is more commonly
encountered in
older horses >7
The diagnosis of IAD (mild to moderate equine
asthma) is based on
(1) the presence of clinical signs of lower airway disease (poor performance, cough)
(2) the documentation of lower airway inflammation based on excess mucus on endoscopy, BALF cytology or abnormal lung function
(3) the exclusion of severe equine asthma (RAO/heaves) as well as infectious and other respiratory diseases
BALF profiles from horses with severe equine asthma (ie, RAO) usually show
moderate to severe neutrophilia (>25% cells) and
decreased lymphocyte and alveolar macrophage
counts
BALF cytology of IAD horses is usually characterized by
> 10% neutrophils, >5% mast cells and >5% eosinophils
mild to moderate increase in neutrophil, eosinophil, and/or mast cell percentages
the definitive host for S. neurona in North America
opossum Didelphis virginiana
Most EPM cases occur in horses aged
4yo or less
OR older > 13
EPM seasonality
greatest risk in fall, then spring summer, lowest in winter
cause of Lyme disease in horses
Borrelia burgdorferi sensu stricto
–transmission vector Ixodes scapularis / Ixodes pacificus
Lyme testing
- -None of the tests consistently detect antibody until 3 or more weeks after infection
- -A positive test result in the absence of previous vaccination indicates exposure from either a current or previous infection. Regardless of test methodology, a positive result does not prove causation of current clinical signs (clinical infection) nor does a positive result predict whether infection is likely to cause clinical signs in the future.
- -There is no known correlation between magnitude of titer and likelihood of disease
Lyme testing of apparently healthy horses
not recommended:
- -low positive predictive value (may be vaccinated, or previously naturally infected)
- -high negative predictive value (unless acutely infected less than one month ago)
naturally occurring syndromes attributed
to B. burgdorferi infection in horses include
neuroborreliosis, uveitis, and cutaneous pseudolymphoma
abrupt pyrexia followed by pharyngitis and subsequent
abscess formation in the submandibular and retropharyngeal lymph nodes
strep equi equi
the most common agent of acute upper respiratory disease identified in horses of 6–10 years age
strep equi equi
Environmental Persistence of S. equi
S. equi remains viable in water for 4–6 weeks but not in feces or soil
Shedding after strangles cases
Nasal shedding persists for 2–3 weeks in most animals.
Horses may be infectious for at least 6 weeks after their purulent discharges have dried up.
Persistent guttural pouch infection may result in intermittent shedding for years.
Horses at risk for development of purpura
SeM (>1:3,200)
Detection of recent strangles infection is evidenced by a __-fold or greater increase in SeM titer of antibody in paired sera taken 10 days apart
4
SeM title of ____ would support a diagnosis of existing S. equi-associated purpura hemorrhagica or metastatic abscessation (bastard strangles)
(titer > 12,800)
Strangles cases in which antibiotics are indicated
- -acutely infected animals with very high fever and malaise before abscess formation,
- -horses with profound lymphadenopathy and respiratory distress,
- -horses with metastatic abscessation,
- -cases of purpura hemorrhagica treated with corticosteroids,
- -guttural pouch infections treated locally and systemically to eliminate the carrier state
Coxiellosis is frequently subclinical, with clinical disease manifesting most commonly in
– small ruminants as late-term abortion, stillbirth, and birth of weak offspring
– rarely as abortion or reproductive failure in cattle.
what is the source of infection for Q fever in humans?
The organism replicates within the trophoblasts of the placenta and after the logarithmic growth phase, produces a spore-like bacterial form termed a small cell variant (SCV); these are responsible
for persistence of the organism in dust and air of
farms
- -Placental membranes, fetuses, and uterine fluids from clinically affected animals can contain massive numbers of C. burnetii
- -also shed in large numbers during parturition in clinically unaffected animals.
coxiella burnetti in ruminants
- -subclinical infection
- -abortion outbreaks with >10% attack rates during the lambing/kidding season of a flock or herd
- -Neonates can also be born alive but weak during
Aborted Fetus
Severe placentitis
Extracellular and intracellular organisms visible in large numbers when direct smears of cotyledon tissues and histopathological sections are examined microscopically.
small ruminants affected by C. burnetii infections
confirm with qPCR testing of placenta and fetal tissue
adiponectin in high or low in older animals
lower
At least 3 hormonal factors, or incretins, are
known to exist in the horse:
gastric inhibitory polypeptide (GIP)
glucagon-like peptides 1 and 2 (GLP-1, GLP-2).
lesions in endocrinopathic laminitis
- -initially found in the secondary epidermal lamellae
- -including lengthening and narrowing, developing tapered tips and with SELs angled more acutely to the primary epidermal lamellar axis
- -Stretching of the lamellar epithelial cells is the earliest histological change
- -accelerated cell death (apoptosis) and proliferation
- -cytoskeletal disruption and deformation of the lamellae
- -divergent laminitic rings can often appear before lameness
Adiponectin
- adipokine secreted exclusively from adipose tissue
- -improves insulin sensitivity and reduces inflammation
- -concentration is inversely related to fat mass and IR
BVDV control strategies and principles have centered on
the elimination of PI animals:
1- use of diagnostics to identify and remove PI
2- use of effective vaccination to prevent the in utero development of PI
3- the implementation of biosecurity/biocontainment principles
Most common BVDV subtype
1980s - 1a
1990s/2000s - 1b
BVDV Vaccines
Modified live virus vaccines provide better clinical protection against fetal infection, abortion, and generation of PI calves.
vaccination of calves w/ MDAntibodies with a MLV vaccine does not affect the efficacy of BVDV vaccination.
the risk of abortion or reproductive failure is low after revaccination of pregnant cattle with an MLV BVDV vaccine during pregnancy when compliant with vaccine label recommendations
an economical and accurate method of identifying PI calves
detection of BVDV antigen in ear-notch samples by antigen-capture enzyme-linked immunosorbent assay
L PMI over aortic and pulmonic valve area Early-to-midsystolic Crescendo-decrescendo or decrescendo Usually grade 1–3/6
physiologic flow murmur
L
PMI over mitral to aortic valve
Holo- or pansystolic or mid-to-late systolic
Plateau (band-) shaped or mid-to-late crescendo
Grade 1–6/6
mitral
L PMI over aortic valve area Holo- or pandiastolic Decrescendo, musical, or both Grade 1–6/6
aortic
R PMI over tricuspid valve Holo- or pansystolic Crescendo or band shaped Grade 1–6/6
tricuspid
Bovine trichomoniasis
—a sexually transmitted disease caused by Tritrichomonas foetus
—In bulls, T. foetus lives in the smegma of the epithelial lining of the penis, prepuce, and distal urethra, and is transmitted to females through infected preputial secretions
—Infected bulls older than 3–4 years of age often are chronically infected
—In cows and heifers, the most common sequela to infection is reproductive failure, but overt clinical signs of infection can include endometritis, salpingitis, placentitis, abortion, and potential subsequent pyometra
—It may take months for cattle to regain fertility.
a herd with a 20–40% prevalence of T. foetus infection in the breeding bulls might expect a ___% reduction in annual calf crop size, a growing period decreased by 12–30 days, and weaning weights decreased by 22–53 pounds
14-50% reduction
Currently, what T. foetus vaccine is available on the US market?
a killed, whole-cell protozoan vaccine
indicated for vaccination of healthy cattle as an aid in the prevention of disease caused by T. foetus
what is the main source of t. foetus
the organism lives in the prepuce of the bull, and it is the bull that is the main source of organism
what are current recommendations for t. foetus vaccinations
there is a lack of conclusive evidence to support the use of this vaccine in areas where good biosecurity practices are in place
best approach to prevent T. foetus introduction into a herd
biosecurity practices:
limiting the potential for bulls from neighboring properties to mate with the herd, purchasing only virgin bulls, purchasing older bulls confirmed to be T. foetus negative, and artificial insemination.
When biosecurity measures are not practiced, the efficacy of these measures cannot be ensured, or if further assurance of a T. foetus free herd is desired, vaccination may also be considered — but evidence for it sucks
Equine piroplasmosis is caused by
one of 2 erythrocytic parasites
Babesia caballi
Theileria equi.
equine piroplasmosis
—tick borne transmission
— erythrolysis leading to anemia
— can persist in equid host indefinitely
—ixodes tick vectors
theileria equi resevoir
persistently infected equid
babesia caballi resevoir
both horses and the primary tick vector
Which piroplasmosis dz is more prevalent
thileria equi
Which piroplasmosis dz has been identified in more northern regions of the northern hemisphere
Babesia
Piroplasmosis:
Regardless of species variation, for both B. caballi and T. equi, infectious________ are transmitted through the tick-saliva to the equid host.
sporozoites
how does theileria invade differently than babesia
it goes into PBMCs first
sporozoites to merozoites
then invade RBCs
asexual replication expands pop until rbcs burst
how to diagnose piroplasmosis on blood smear
stain with Giemsa, Wright’s, or Diff-Quik®, may reveal organisms during the acute stage of infection
— even during severe infection, the percent parasitemia remains so low that false-negative results are not uncommon.
The piroplasms of T. equi and B. caballi can be easily distinguished from one another within the erythrocyte
—B. caballi typically appears as 2 large pyriform (pear-shaped) merozoites that measure approximately 2–5 um in length
—less than 1% erythrocytes infected
—T. equi merozoites occur within erythrocytes as polymorphic, small piroplasms occasionally in a distinct Maltese cross-formation; smaller and typically measure 2–3 um
—5-20% erythrocytes infected
serologic tests for piroplasmosis
cELISA: most sensitive for chronic T. equi. utilizes recombinant EMA-1 and specific monoclonal antibodies. EMA-1 is an immunodominant, highly conserved surface antigen specific to T. equi. detectable as early as 21 days after experimental infection and 5 weeks after tick transmission.
CFT: activation of complement upon specific interaction of antibody and antigen. very specific, lacks sensitivity, especially in chronic infection or after treatment.
IFAT: high specificity, low sensitivity but better than CFT
piroplasmosis treatment
In endemic regions, treatment of piroplasmosis is used only as a means of decreasing clinical signs and reducing fatalities. Clearance of the organism serves no purpose in these countries as life-long immunity (premunity) is assumed to be conferred with chronic, inapparent infection.
In non-endemic regions attempting to remain free of piroplasmosis, treatment of infected horses with the intent of clearance (chemosterilization) is desired.
Imidocarb ID diproprionate salt
The viral pathogens associated with BRD include:
bovine herpesvirus type 1 (BHV-1)
parainfluenza-3virus (PI3)
bovine viral diarrhea virus (BVDV), and bovine respiratory syncytial virus (BRSV)
The Bacterial pathogens associated with BRD include:
Mannheimia haemolytica
Mycoplasma bovis
Pasteurella multocida
Histophilus somni
Which acute phase protein is best for diagnosing BRD?
None
Traditionally, the identification and diagnosis of mycoplasma has been performed via
culture
can be easily overgrowm - add abx
“fried egg”
More recently, the use of ________ to detect Mycoplasma species from various bovine samples has increased
PCR
Polymerase chain reaction has a higher efficiency, specificity, and sensitivity for laboratory diagnosis when compared with conventional culture-based methods
_______ allows the detection of antimycoplasma antibodies in sera and milk
indirect ELISA
— good for individual animal samples as well as BTM samples
Clinical mycoplasma mastitis is often characterized by
—multiple affected quarters coupled with unresponsiveness to treatment
—Adults and calves can also be affected by arthritis and pneumonia
—otitis media is typically only observed in calves
—All of these clinical manifestations may be observed concurrently with mycoplasma mastitis in the herd
