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32 Cards in this Set
- Front
- Back
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what is the aetiological agent of african horse sickness? how is it spread and what virus is it closely related to
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african horse sickness virus. related to bluetongue and spread by culicoides species
endemic in eastern and cantral africa |
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here does AHS virus first multiply in the body and what does it later cause?
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multiply in regional lymph nodes and then disseminate to endothelial cells of target organs --> effusion and oedema
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name the 4 forms of AHS
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pulmonary - peracute
cardiac - acute mixed horse sickness fever |
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what are the clinical signs of the pulmonary form of AHS?
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pyrexia 1-2 days
acute severe dyspnoea, coughing, froth out nostrils death in a fe hours 95% MORTALITY |
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what are the clinical signs of the cardiac form of AHS?
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pyrexia for 3-4 days
subcut oedema of head and neck resultant dyspnoea and dysphagia colic due to gut emphysema petechiation death in 4-8 days of pyrexic onset 50% MORTALITY |
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what are the clinical signs of the mixed form of AHS?
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cardiac form progresses to pulmonary or vice versa
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what are the clinical signs of horsesickness fever and which species does this tend to affect?
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often subclinical
pyrexia anorexia mild dyspnea and tachypnoea donkeys, zebra and immune horses |
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what are the differentials for AHS (5)?
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anthrax
EIA EVA encephalitis piriplasmosis purpura haemorrhagica |
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how do you diagnose AHS?
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elisa serology
PCR VI |
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how do you prevent AHS?
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vaccination
reduce midge exposure by stabling at dawn and dusk, insect proofing stables, using insect repellants/traps and eliminating stagnant water |
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what are the clinical signs of west nile virus (WNV) - 7?
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weakness
pyrexia behavioural changes cranial nerve deficits ataxia muscle fasciculation can progress to complete paralysis of one or more limbs - euthanased |
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which horses may make complete recovery from WNV?
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those that make rapid improvement in first week - others may ahve residual CNS effects
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how is WNV diagnosed?
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serology
PCR immunohistochemistry |
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what are the differentials for WNV? (5)?
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Rabies
EPM EHV1 verminous meningoencephalopathy HE |
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how do you treat WNV?
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hyperimmune plasma
interferon a supportive euth if severe |
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What does Yew toxicity cause and how does it work?
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contains alkaloids and taxins that block Na movement and depress myocardium: COLLAPSE AND SUDDEN DEATH - preceded by tremors and weakness
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what may high doses of cardiac glycoside containing plants result in?
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asystole and increased vagal tone to the SAN and AVN
(act on Na/K pump resulting in decreased intracellular K |
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what are the clinical signs of oak (acorn) poisoning (7)?
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colic
rectal tenesmus haemorrhagic diarrhoea intestinal borborygmus tachycardia tachypnoea acorn poisoning may cause sudden death |
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which plants contain a lot of selenium?
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senecio species
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what are the clinical signs of acute selenium toxicity?
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lethargy
weakness colic diarrhoea arrhythmia dyspnoea |
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what are the clinical signs of chronic selenium toxicity?
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loss of mane and tail
thin fragile body hair lameness from laminitis, hoof slippering and sloughing |
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how is selenium toxicity diagnosed and treated?
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assay selenium in mane and tail
remove source and feed diets high in protein |
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what fungi can cause aflatoxicosis? what are the clinical signs?
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aspergillus flavus and parasiticus that form in CHO in field and storage
cause liver disease, colic and can be fatal |
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what toxins are responsible for ryegrass staggers?
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neurotoxic alkaloids produced by endophytes - normally have symbiotic relationship with certain grasses
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what are the clinical signs of ryegrass staggers?
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diffuse vestibulocerebellar syndrome
hypometric ataxia proprioceptive deficits wide-based stance muscle tremors |
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what causes cantharidin intoxication?
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ingestion of dead beetles entrapped in hay at harvesting
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what are the clinical signs of blister beetle toxicosis and why?
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severe colic - inflammation and necrosis of gastrointestinal tract!
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what are the clinical signs of lead toxicity? how do you diagnose and treat it?
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weak
weight loss dysphagia dysphonia proprioceptive deficits muscle tremours blood, tisusue lead (liver) chelation therapy: EDTA |
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what does carbamate poisoning do to the body? what are teh clinical signs and how may you diagnose it?
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--> depress acetylcholinesterase
--> muscarinic or nicotinic overstimulation signs for 36-48 hours resulting in recovery or death profuse salivation colic lacrimation miosis sweating dyspnoea coughing from excess resp secretions tetatny CNS depression or stimulation ATROPINE may counteract parasympathetic signs |
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what are the clinical signs of vitamin K3 toxicity?
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acute and chronic renal failure
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how does monensin result in toxicity in horses? what are the clinical signs
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interferes with transport of Na and K between intra and extracellular spaces: heart primary target
mild inappetance to sudden death from hypovolaemic shock ataxia muscle weakness anorexia colic seating tachydysrhythmias haemolysis myoglobinuria cardiac, renal and hepatic failure |
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how is monensin toxicity diagnosed and treated?
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diagnosed via LV overload on echocardiogram, elevated AST, CK and UA
TX supportive - digitalis is CONTRA-INDICATED |
