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what is incubation/shedding and clinical signs seen with flu?
- incubation 1-3 days; shedding w/in 48 hours
- fever for 5 days
- decr. appetite, dry cough
- nasal discharge
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how long is clinical course of flu? how long does cough persist? Is there a carrier state?
- 7-14 days
- cough up to ~21d = NO training
- no carrier state
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what are some secondary complications of flu that can be severe?
- bacterial pneumonia
- myocarditis
- limb edema
- wt loss
- (death in compromised)
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how is flu diagnosed?
- PCR from nasopharyngeal swab
- ELISA, paired titers
- virus isolation (need swab 1-2d prior to CS)
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how is flu treated?
- NO training (1 wk for ever day of fever)
- supportive/rest +/- NSAIDS
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who should get flu vx? how often do they need it?
- high risk horses like show/performance and comingled
- every 4-6 months
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what types of vaccines are available for flu?
- killed (not likely to protect against Ag-shift)
- live (intranasal, may protect longer)
- canary pox (recombinant - good against recent strains)
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which form of herpes is associated with abortion storms and myeloencephalopathy?
EHV -1
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what kind of viruses are herpes? what tissue do they target?
- double stranded DNA
- vascular endothelium (vasculitis, hemorrhage, thrombosis)
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Ability to fight herpes infection is related to what immune response?
cytotoxic T cell response
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how is herpes diagnosed?
nasal swab for viral isolation or ELISA
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which herpes patients should be treated with acyclovir?
those with neuro form (myeloencephalopathy)
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Vaccines for herpes do not protect against what? when should horse be given the vx? how many doses/how often?
- neuro form
- (some protection against resp/abortion)
- 5-6mo old foals; 3 dose series
- repeat every 4-6 mos (short immunity)
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how long can horse shed herpes after being vaccinated?
28 days - isolate
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where does herpes remain latent?
trigeminal nerve ganglion
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which breed harbors EVA?
standardbred stallions
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what type of virus is EVA? how is it transmitted?
- single stranded RNA
- fomites, aerosol, venereal
- 3-14 day incubation
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what are clinical signs of EVA?
- subclinical respiratory disease
- flu-like symptoms (fever, cough)
- conjunctivitis
- edema/vasculitis
- (death not common but can occur)
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who should be vaccinated against EVA?
- intact colts intended for breeding (at 6 and 12 months)
- mares prior to breeding w/carrier stallion
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what is problem with vaccinating young colts?
test seropositive and cant distinguish from natural infection
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who gets disease from rhodococcus equi?
- 3wk -6mo old foals
- (adults shed but not clinically affected)
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how long is incubation period for rhodoccocus?
9d-4wk
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what type of bacteria is rhodococcus? where in the body does it reside?
- G+ intracellular pleomorphic rods w/VapA virulence factor
- alveolar macrophages
- ubiquitous in environment
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what does MDB reveal with rhodococcus infection? how is definitive diagnosis made?
- leukocytosis, elevated fibrinogen
- transtracheal wash for cytology/culture
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what do rads show with rhodococcus infection?
- chronic pyogranulomatous bronchopneumonia extensive pulmonary abscessation
- bronchoalveolar pattern
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are rads a helpful prognostic indicator in cases of rhodococcus?
- no, even really bad lungs can still respond to tx
- auscultation does not correlate with dz severity either
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what will thoracic US show with rhodococcus infection?
- superficial abscesses and pleural irregularities
- -good screening tool
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what are immune mediated side effects seen with rhodococcus?
- polysynovitis - not septic, not lame - don't need culture
- panophthalmitis (give NSAIDs/atropine)
- colic/mesenteric lnn abscesses
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how is rhodococcus treated?
- erythromycin
- azithromycin(SID)/clarithromycin + rifampin
- doxycycline + rifampin
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what are negative side effects seen with erythromycin?
- foal: tachypnea, hyperthermia, diarrhea
- mom licks foal - possibly fatal colitis
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although expensive what is the advantage of hyperimmune plasma for rhodococcus?
provides passive immunity when given first few days of life then 2nd dose 25d later
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can rhodococcus patient be expected to race again?
possible; if full recovery achieved, can compete as well as siblings
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what should be done with foals on farms with endemic rhodococcus?
weekly US screening of thorax and check TPR
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what are 2 important pathogens of neonatal (birth to 1mo) pneumonia?
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what are most common causes of bacterial pneumonia in foals 1-6mo?
- strep zoo
- r. equi
- (anaerobes are infrequent)
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what is an opportunistic pathogen, eukaryote that is seen in compromised patients?
pneumocystis carinii
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what is cause of exercise induced pulmonary hemorrhage?
- intense exercise - incr. pulmonary a pressure - negative inspiratory pressure - ruptures capillaries
- (NOT related to duration)
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who is affected by EIPH?
- all TB racehorses
- most SB; 62% QH
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