Infectious disease of the horse Flashcards
what are the three types of infectious disease
- viral
- bacterial
- protozoal
what is the purpose of viral diseases
- to stay alive and keep genetics going
what is EIV
- equine influenza
- most common infectious disease
- most common cause of respiratory illness
what are signs of EIV
- fever, lethargy, anorexia, serous nasal discharge,
- cough, mucoid nasal discharge
how is EIV transmitted
- inhalation of aerosolized virus
- direct contact with infected horse
- contact with contaminated fomites ( any contaminated surfaces = waterers, feeders and barn tools)
who can be effected by EIV
- crowded horse practices
- unvaccinated horses
- 1-5 year olds
- international trade
- droplets infectous spread
- dogs by being in close proximity and eating horse meat
what can get EIV
zebras
dogs
camels
humans
what are three major outbreaks
1872: north american outbreak
1987 india outbreak
2007 australian outbreak
when was the canadian outbreak and where was it
- began in toronto
- because of transportation and pathways
- it spread through horses and trains that transported horses
- detrimental to the firefighters cause there were no horses to pull water
what was the morbility of EIV
- 60-90%
how can you treat EIV
- rest in a well ventilated area
- do not put horse to work to quickly
- working a horse to quickly can cause perminant damages
what perminant damages can be done to a horse if they return to work to early after EIV
- pneumonia - scars in lungs
myocarditis - inflammation of heart muscles - heaves - allergy response
how can you prevent EIV
- minimize exposure
- vaccinate - but virus can change antigenic variations (so we need to continously change vaccines
what challenge is prevented with EIV
- genome is antisense RNA
- the viral RNA polymerase is error prone (contributing to virus survival)
should you vaccinate againsts EIV
- maybe
- vaccines are specific to serotype
- protection is generally short lived (every 4 months)
- balance risks and bennifits
what is equine herpesvirus
- infects and stays with horse forever
- latenet and persistant infections
- recrudescence
what is the most concerning types of herpesviruses
rhinopneumonitis - (EHV 1 and 4)
respiratory infection
EHV -1 abortion, venereal disease (sometimes EHV-4)
myeloencephalopathy - EHV 1 - neural
what are symptoms of rhinopneumonitis
- highly contagious upper respiratory disease
- establishes latency in infected horses
what does previous exposure/ infection do in EHV
- higher risk of neural disease
morbiditiy low - 90%
mortality up to 40% ( those diagnosed are uthenized)
what type of response does EHV vaccine have
- inactivates or kills virus
- produces antibodies for humoral response
what is EHV-3
- acute venereal disease
- ulceration of vagina and vestibular mucosa or mares and penis and prepuse of stallions
- in breeding, some horses can be carriors but will not spread disease if there are no clinical signs
what is EHV 5
- multinodular pulmonary fibrosis
- chronic, progressive interstitial lung disease
- hides in the body until immunocompremised
signs of equine viral arteritis (EVA)
- fever
- upper respiratory disease
- petechial hemorrhage of mucous membranes
edema of limbs = sure diagnostics
how does EVA infect a fetus
- causes abortion
- infects the fetus itself
- outbreaks are usually from contaminated semen
- of stallions using the same infected equipment
how can EVA be spread
- venereal spread (sexually)
- through contaminated semen
- inhalation of aerosolized virus
( stallions infected are usually asymptomatic )
how many stallions/ colts are EAV carriors
30-60%
is there a vaccine for EVA
- yes,
reccomended to vaccinate those that are breeding with a carriror - problem with test is it doesnt distinguish if its a carrier or not
what is EEE
eastern equine encephalomyelitis
or the sleeping disease
how is EEE transmitted
- perching birds
- guarder snakes
- mosquitos
- never horse to horse (always infected host to horse)
what is the process from sleepy appearance to paralysis
- 1-3 week incubation
- hypersensitivity
- dozy, ataxic
- severe paresis and inability to swallow
- 2-4 days = death
is EEE curable
- 75-90% fatal
- horses that do recover often suffer permanent brain damage
what is WNV
west niel virus
- transmitted mostly from birds or mosquits
what is the mortality for west niel virus
- 30% mortality
- morbidity 5-30% (feild study where they didnt know how many were bitten)
- long lasting effects observed in those suposidly recovered
what are clinical signs of west niel virus
- depression
- hindquarter weakness
- ataxia
- tremors/ convulsions
- thrashing and recumbency
what is the treatment of west niel virus
- making horses comfortable
- hydrated
- if they become recumdent = put them in a sling
prevention of WNV
- vaccine
- keep mosquits off horse
what is rabies
- lyssavirus within family rhabdoviridae
- 100% fatal with onset of symptoms
zoonotic - 2-12 wekk incubation
how is rabies spread
- from salivia through an open wound (bite)
- infects peripheral spinal nerves (in all infected)
- CNS
and distributed through salivary glands - kills host
what is EIAV
-equine infectous anemia virus
also known as swamp fever
- no way to control it - retroviral pathogen
- seroconvonversion - changes continously
- have to contiously develope the vaccine
how is EIAV transmitted
- horse is the only host
- infected horses pass is on through horse flys and deerflys
- mosquitos dont carry enough of the blood to pass it on
- stays in fly for 48 hours
what are symptoms of EIAV
- acute fatal or chornic
- bouts of weakness
- loss of condition
- febrile episodes
- anemia
what can you do for EIAV
- life-long quarentine ( 1km away at all times)
- you are repsonsible if another horse gets it from your horse
- euthinazia - someone has to watch to burry the horse (food inspection agency)
