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
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
what are some secondary complications of flu that can be severe?
- bacterial pneumonia
- limb edema
- wt loss
- (death in compromised)
how is flu diagnosed?
- PCR from nasopharyngeal swab
- ELISA, paired titers
- virus isolation (need swab 1-2d prior to CS)
how is flu treated?
- NO training (1 wk for ever day of fever)
- supportive/rest +/- NSAIDS
who should get flu vx? how often do they need it?
- high risk horses like show/performance and comingled
- every 4-6 months
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)
which form of herpes is associated with abortion storms and myeloencephalopathy?
what kind of viruses are herpes? what tissue do they target?
- double stranded DNA
- vascular endothelium (vasculitis, hemorrhage, thrombosis)
Ability to fight herpes infection is related to what immune response?
cytotoxic T cell response
how is herpes diagnosed?
nasal swab for viral isolation or ELISA
which herpes patients should be treated with acyclovir?
those with neuro form (myeloencephalopathy)
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)
how long can horse shed herpes after being vaccinated?
28 days - isolate
where does herpes remain latent?
trigeminal nerve ganglion
which breed harbors EVA?
what type of virus is EVA? how is it transmitted?
- single stranded RNA
- fomites, aerosol, venereal
- 3-14 day incubation
what are clinical signs of EVA?
- subclinical respiratory disease
- flu-like symptoms (fever, cough)
- (death not common but can occur)
who should be vaccinated against EVA?
- intact colts intended for breeding (at 6 and 12 months)
- mares prior to breeding w/carrier stallion
what is problem with vaccinating young colts?
test seropositive and cant distinguish from natural infection
who gets disease from rhodococcus equi?
- 3wk -6mo old foals
- (adults shed but not clinically affected)
how long is incubation period for rhodoccocus?
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
what does MDB reveal with rhodococcus infection? how is definitive diagnosis made?
- leukocytosis, elevated fibrinogen
- transtracheal wash for cytology/culture
what do rads show with rhodococcus infection?
- chronic pyogranulomatous bronchopneumonia extensive pulmonary abscessation
- bronchoalveolar pattern
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
what will thoracic US show with rhodococcus infection?
- superficial abscesses and pleural irregularities
- -good screening tool
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
how is rhodococcus treated?
- azithromycin(SID)/clarithromycin + rifampin
- doxycycline + rifampin
what are negative side effects seen with erythromycin?
- foal: tachypnea, hyperthermia, diarrhea
- mom licks foal - possibly fatal colitis
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
can rhodococcus patient be expected to race again?
possible; if full recovery achieved, can compete as well as siblings
what should be done with foals on farms with endemic rhodococcus?
weekly US screening of thorax and check TPR
what are 2 important pathogens of neonatal (birth to 1mo) pneumonia?
what are most common causes of bacterial pneumonia in foals 1-6mo?
- strep zoo
- r. equi
- (anaerobes are infrequent)
what is an opportunistic pathogen, eukaryote that is seen in compromised patients?
what is cause of exercise induced pulmonary hemorrhage?
- intense exercise - incr. pulmonary a pressure - negative inspiratory pressure - ruptures capillaries
- (NOT related to duration)
who is affected by EIPH?
- all TB racehorses
- most SB; 62% QH