Specialty Reading Q's Flashcards
CS, Articles
DPJ is associated with a poor prognosis when
abdominal fluid T.P. > 3.5g/dL
anion gap increases to 15mEq/L or above
Which point mutation of the beta-2 integrins cause bovine leukocyte adhesion deficiency?
CD18
What does bovine leukocyte adhesion deficiency cause?
marked and persistent neutrophilia
hypergammaglobulinemia
chronic, recurrent bacterial infections and death
Clinical signs in calves appear within a couple of weeks after birth and include anorexia, fever, chronic pneumonia, chronic diarrhea, severe ulcers on oral mucosal membranes, ulcerative stomatitis, gingivitis, periodontitis, loss of teeth, impaired wound healing, chronic dermatitis, decreased growth rate, and death
Lethal Trait A46 in cattle causes
- bovine hereditary zinc deficiency
- reduced lymphocyte numbers
- Calves with skin lesions, diarrhea, and bronchopneumonia.
- Death occurs at approximately 4 months, secondary to bronchopneumonia or complicated diarrhea
IN CALVES - Catabolism of plasma derived immunoglobulins occurs when?
rapidly in the first 12 hours
What is the point of using oligosaccharides (OS) in unpasteurized colostrum?
to decrease adverse effects of colostral bacterial contamination
Which Salmonella species stimulates antibody production and secretion in colostrum in vaccinated cows?
Newport
What drug increases absorption of colostral IgG when administered orally?
cisapride
what causes digital dermatitis
treponema
common dermatophyte in cattle
Trichophyton verrucosum
Which site is most affected by bovine ocular squamous cell carcinoma?
lateral limbus
immunosuppression associated with BVDV infection in calves is due to?
increased neutrophil destruction
Which clinical manifestation is the most economically important in pigs with disease caused by Erysipelothrix rhusiopathiae?
endocarditis
A 100–cow grazing dairy fed total mixed ration once has had increase in incidence of clinical mastitis due to several Gram-negative infections.
Which one of the following management methods will most likely reduce the incidence of mastitis?
adding selenium to the TMR
What is the infective stage of dermatophilosis in cattle?
zoospores
In cohort studies of the role of a risk factor in the etiology of disease, it is essential that:
The exposed and non-exposed groups under study be as similar as possible with regard to possible confounding factors.
Consensus statement definition of EPIH
the presence of blood detected on tracheobronchoscopic examination after exercise, presence of red blood cells in bronchoalveolar lavage fluid, or both.
There is no consensus about the concentration of red blood cells in bronchoalveolar lavage fluid that is diagnostic of EIPH, and the definition varies among reports.
Does EIPH adversely affect the health / welfare of horses?
This question is important because evidence of an adverse effect of EIPH on the health or well-being of horses has potential ramifications for use of horses for racing.
-no evidence of increased risk of sudden death in horses with EIPH.
EIPH Grade 1-3 is not associated with a shorter racing career of Thoroughbred horses
Thoroughbred horses with epistaxis or Grade 4 EIPH have shorter careers.
some horses with EIPH have extensive and characteristic pulmonary lesions.
moderate quality evidence that EIPH is progressive and related to load of racing.
There is no published evidence regarding the heritability of EIPH. There is very low quality evidence of an association of pedigree with occurrence of epistaxis.
Does EIPH affect the athletic capacity of horses? An adverse effect of EIPH on athletic capacity might influence decisions on the use of interventions to decrease the severity or incidence of EIPH.
moderate to severe EIPH in Thoroughbred race horses is associated with increased likelihood of inferior finishing position in a race.
There is very low quality of evidence that EIPH in Standardbred racehorses is not associated with finishing time in a race.
There is moderate quality evidence that Thoroughbred racehorses with more severe EIPH finish farther behind the winning horse in a race.
There is moderate evidence that severity of EIPH in Thoroughbred racehorses is negatively associated with a horse’s race earnings.
There is low quality evidence of a dose-response relationship between severity of EIPH in Thoroughbred racehorses and severity of impaired performance.
Are there effective prophylactic interventions for EIPH? The capacity to manage EIPH is dependent on the existence of medications or interventions that decrease the severity or incidence of 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.
There is moderate quality evidence that furosemide reduces pulmonary vascular pressure during strenuous exercise.
There is very low quality evidence that nasal strips, herbs, aminocaproic acid, NSAIDs, corticosteroids, pentoxifylline, or bronchodilators affect EIPH severity.
Does furosemide affect the athletic capacity of horses? An association of furosemide administration with superior performance has been suspected since the drug was first used in race horses and continues to be contentious.
There is moderate quality evidence that furosemide administered IV 4 hours prior to racing is associated with improved racing outcomes in Thoroughbred and Standardbred racehorses.
There is low quality evidence that furosemide administered IV 4 hours before treadmill exercise results in delayed onset of fatigue and improved energetic cost of locomotion.
Increased expression of genes encoding for TNF-a, IL-1b, and IFN-c and protein concentrations (TNF-a and IFN-c) have been repeatedly linked with abnormal BALF cytology findings, both in the presence and in the absence of clinical signs, suggesting that activation of the____________ and TH-? response are often involved in the pathogenesis of IAD and most likely drive the luminal neutrophilia
innate immune system and TH-1 response
mRNA expression of IL-17 and IL-23 have been also linked with increases in BALF neutrophil percentage, and increases in IL-4 and IL-5 with the mastocytic form of IAD, which would support an implication of the _______ in  some IAD phenotypes.
adaptive immune response, including Th-2 type polarization
Diagnosis of IAD 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 >2-3/5, BALF cytology >10% neutrophils, >5% mast cells and >5% eosinophils or abnormal lung function, and
(3) the exclusion of severe equine asthma (RAO/heaves) as well as infectious and other respiratory diseases (see differential diagnoses).
Definitive host for s-neurona in north America
The opossum Didelphis virginiana
S. neurona life cycle
Sarcocystis neurona has a 2-host life cycle
- definitive host: opossum (Didelphis virginiana)
- multiple mammal intermediate hosts
Sexual reproduction by the parasite in the intestinal epithelium of the infected opossum results in the production of sporozoite-containing sporocysts that are passed in the feces.
The sporozoites are infectious for the intermediate hosts, which include skunks, raccoons, armadillos, and cats.
S. neurona forms latent sarcocysts in the muscle tissue of the intermediate host; sarcocyst-laden muscle is the source of infection for the opossums
Horses are infected with S. neurona by ingesting food or water that has been contaminated with feces from an infected opossum.
EPM seasonal risk
Fall 6x higher
Spring/summer 3x higher
Winter lowest risk
Factors affecting EPM risk on farms
+ previous EPM diagnosis
+ presence of opossums
+ presence of wooded areas
- wildlife prevented from feed
- river or creek present
Which EPM tests are currently offered commercially that provide information regarding intrathecal antibody production based on serum and CSF titers?
The SnSAG2, 4/3 ELISA serum:CSF titer ratio
NhSAG1 ELISA serum:CSF titer ratio
diclazuril and ponazuril are
benzeneacetonitrile compounds
anticoccidial
these drugs are related to the herbicide atrazine and are thought to target the parasite’s apicoplast organelle.
Sulfonamides and pyrimethamine act synergistically by
interfering with folic acid metabolism and biosynthesis of purine and pyrimidine nucleotides necessary for the parasite’s survival.
Lyme disease-The primary North American genospecies
Borrelia burgdorferi sensu stricto, with Ixodid ticks being the vector for transmission
Ixodes scapularis in eastern North America and Ixodes pacificus on the North American west coast.
B burgdorferi life cycle
2-year enzootic cycle
East: ixodes scapularis and white footed mouse
West: ixodes Pacificas and grey squirrels
- reservoir host for spirochetes and infect tick larvae and nymphs
Deer + large mammals maintain adult ticks
Organism transferred to mammal when the tick feeds
Lyme diagnosis in horses
Diagnosis of current or previous infection with B. burgdorferi is most commonly achieved via serologic testing.
Positive test results indicate presence of antibodies against B. burgdorferi at the sampling time point and might represent different infection stages depending on the test utilized.
Commercially available laboratory tests currently include IFAT, ELISA, whole cell Western blot, and a bead-based multiple antigen ELISA assay (Multiplex). A point of care C6 SNAP marketed for dogs has also been utilized for testing horses. 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.
Borrelia-associated uveitis
Clinical findings usually include severe and most often bilateral ocular disease consistent with chronic uveitis, including a yellow-green fibroid aqueous humor, aqueous flare, synechiae, miosis, preiridal fibrovascular membrane formation, and other iris changes such as rubeosis iridis and loss of corpora nigra.
Prognosis for vision is poor.
Cutaneous pseudolymphoma associated with B. burgdorferi infection
characterized by dermal, papular to nodular lesions that occurred at the site of the tick bite.
Histologic evaluation was suggestive of lymphoma but immunohistochemistry revealed mixed lymphoid hyperplasia and Borrelia PCR performed on the tissue was positive.
Borrelia-associated cutaneous pseudolymphoma should be considered for horses in endemic regions with focal infiltrative skin lesions, particularly if the site corresponds to that of a known tick bite.
Abx treatment yielded good outcome
Milk from mares that have recovered from strangles contains immunoglobulin ?
IgGb and IgA
Coxiella burnetii
Small, pleomorphic, intracellular, gram negative bacterium
Infections principally occur through inhalation or ingestion, although infection by blood transfusion occurs.
Infections in animals are termed coxiellosis.
Where does coxiella replicate
within the trophoblasts of the placenta
after the logarithmic growth phase, produces a spore-like bacterial form termed a small cell variant (SCV)
- these SCVs are responsible for persistence of the organism in dust, manure, and the air of farms
- Aerosols originating from infected farms can act as a source of infection for humans
How can coxiellosis be most accurately diagnosed at the herd/flock level with consideration of the individual animal level?
qPCR: animals with abortion caused by C. burnetii. fetal tissues (liver, abomasal fluid, and lung) can also be PCR-positive. High numbers of organisms as evidenced by qPCR values combined with histopathologic placental lesions provide strong evidence that the abortion is caused by C. burnetii.
ELISA: Preferred for large scale screening of livestock, Good agreement with IFA results
Immunofluorescence Assay (IFA): Definitive serological test in human medicine.
Complement Fixation Test (CFT): Less sensitive than most ELISA (as low as 10% in aborting animals); good specificity (>98% • Negative ELISA samples may show low CFT titres, possibly detecting IgM • Limited utility in livestock.
What testing programs are recommended for infected herds and flocks to control clinical and subclinical coxiellosis, including shedding of the agent and transmission to other herds and flocks?
BTM ELISA is a useful test for large scale screening programs to detect flocks that have been previously infected
BTM PCR is more sensitive for detection of actively infected/shedding flocks.
In dairy goat herds, BTM ELISA also is similarly predictive of shedding status when measured with BTM PCR (cut-off 100 bacteria/mL milk) and also for detecting previously infected herds with seroprevalence of >15% (SP ratio of 43%)
Bulk tank milk containing >105 C. burnetii/mL as estimated by qPCR is associated with herd seroprevalence of ≥50% in dairy cattle.
The most beneficial tool that has been described for management of clinical disease is the implementation of vaccination using phase I form of the killed bacteria.
Once coxiellosis is confirmed on a premises, infections should be considered endemic in the population.
How can the transmission and zoonotic risks of coxiella be mitigated?
- Segregate periparturient animals from other high-risk animals (gestating and young). This may decrease exposure to the high level or organisms in aborted fluids.
- Manage parturient animals in an enclosed environment with controlled airflow to lower risk for down-wind transmission. This may increase risk of seroconversion for animals housed within the same environment.
- Eliminate land application of fresh manure.
- Compost manure for 90 days before land application and transport manure and apply only on damp low-wind days
- Promptly remove and dispose of aborted fetus and uterine fluids either by closed composting or burning.
- Move naïve or gestating animals to areas of the farm that are upwind of aborting animals.
- Minimize development of excessively dry and dusty environments in animal housing areas (mist or gently wetting down dusty environments) and around barns.
resistant to the action of abx drugs due to inherent structure or physiology of the bacteria
constitutive resistance
mechanisms:
1- lack of cellular mechanisms required for antimicrobial action (eg penicillin resistance dt lack of correct binding proteins)
2- growth rates too slow for effective action (beta-lactams)
3- resistance in anaerobic bacteria to aminoglycosides dt lack of oxygen-dependent uptake of the antimicrobial into the cell
developed mechanisms to circumvent action of the drugs through genetic mutation or through acquisition of genetic elements
acquired resistance
mechanisms: drug inactivation, drug modification, production of competitive metabolites, target mutation, target substitution, target modification, decreased cell wall permeability to drugs, active efflux of drugs, and failure to metabolise a drug to its active form
chloramphenicol, nitroimidazoles, nitrofurans in food animals
FDA banned over concerns of harmful residues
glycopeptides, extra-label use of fluoroquinolones and cephalosporins in food animals
FDA banned because they pose a risk for causing AMR that can be transferred to people
mechanism of resistance to benzimidazoles
beta-tubulin
mechanism of resistance to ivermectin
P-glycoprotein gene
anthelmintics recommended for small ruminants
ORAL ONLY
DO NOT ROTATE WITHIN A GRAZING SEASON
make sure the drench gets into the rumen so appropriate contact time can ensure killing
most important factor contributing to selection for anthelmintic resistance
levels of refugia
1) stages of parasites in the host that are not affected by the drug tx
2) parasites residing in animals that are left untreated w a partic drug
3) free-living stages in the environment at the time of tx
biosecurity recommendations for small ruminant parasites
Current recommendation is to quarantine (on dry lot where faeces can be removed) every new addition, dose w triple-class anthelmintic therapy, and perform FECRTss
Feed should be withheld for 24 h before tx, then moxidectin, levamisole, and albendazole should be administered consecutively (do not mix drugs together)
Retest 14 d later: FEC should be zero, and flotation should yield very few or no eggs
After this tx, animals should be placed on a contaminated pasture. Never should an animal be placed onto a clean pasture after a triple anthelmintic class treatment regimen is administered, bc any surviving worms will be triple resistant and there will be no refugia on pasture to dilute the future transmission of any eggs that are shed
what sheep breed has high heritability of FAMACHA scores
merino
signs of grey matter involvement
focal muscle atrophy and severe muscle weakness
signs of white matter involvement
ataxia and weakness in limbs caudal to site of infection
test of choice for detection of EHV-1
PCR on NASAL SWAB
acyclovir
Thymidine kinase inhibitor
synthetic purine nucleoside analog that selectively inhibits the replication of herpesviruses
this drug phosphorylated initially by viral thymidine kinase, followed by 2 other phosphorylations by host cell kinases à triphosphate acyclovir compound binds to and inhibits the viral DNA polymerase for the formation of viral DNA
PK of acyclovir after single po admin (10 and 20 mg/kg) to adult horses has been associated w high variability in serum acyclovir-time profiles and poor bioavailability below the concentrations required for viral inhibition
on culture, which strep ferments sorbitol and lactose
strep equi zoo, NOT strangles
immune complex is a type ? hypersensitivity
III
negative prognostic factors in for horses with structural heart disease
progressive chamber remodelling (dilatation and altered chamber shape) and dysfunction
great vessel enlargement
the development of pulmonary hypertension, CHF, and potentially dangerous arrhythmias
Any left-sided holodiastolic murmur I an adult horse
assumed aortic regurg until proven otherwise
Often mild and associated w normal performance and life expectance
If moderate to severe or first recognised in younger horse (<10) risks for reduced performance life and longevity higher
Continuous machinery murmur loudest on right side of thorax w bounding arterial pulses is characteristic of ?
aorta-cardiac fistula
Ultrasound monitoring of ascarids in foals
- Can detect burdens of > 10 worms
- most reliable findings were in loops within 5cm of the abd wall
Tapeworm species in horses
Anoplocephala perfoliata, A. magna and Anoplocephaloides mamillana (formerly known as Paranoplocephala mamillana).
Of these, A. perfoliata is by far the most prevalent and the other two species are reported only sporadically
Equine tapeworm treatment
Pyrantel pamoate paste 13.2mg base/kg
praziquantel 1mg/kg
Primary Causes of Recumbency Initiating the “Downer Cow Syndrome”
Parathyroid hormone (PTH) effects at the surface of target bone and kidney cells.
A) Under normal conditions, PTH released in response to hypocalcemia interacts with its receptor, located on the surface of bone and kidney cells, in a lock and key fashion. This stimulates G proteins and adenylate cyclase (adenylate cyclase complex) resulting in production of cyclic AMP, which acts as a second messenger within the cytosol of target cells. This initiates mechanisms such as bone Ca resorption and renal production of 1,25-dihydroxyvitamin D to restore blood Ca concentration to normal levels.
(B) Alkalotic conditions induced by high-potassium diets induce a change in the shape of the PTH receptor protein so that it is less able to recognize and bind PTH, resulting in failure to activate the cell by producing cyclic AMP.
(C) Mg is required for function of the adenylate cyclase complex. Hypomagnesemia reduces ability of PTH stimulated cells to produce cylic AMP, resulting in failure to activate the cell.
mycobacterium spp
