rabies Flashcards
rabies: zoonosis
lethal neurological disease, universally endemic in mammals, has been eradicated from some countries (great britain,new zealand and iceland), can pass from animals to humans
epidemiology
only transmitted through saliva to warm-bodied animals by the bite of an infected animal, in the US rabies infection of wild animals occurs in geographically defined regions, transmission is usually within the same species and may also occur between species, clinical signs are only shown once the virus arrives in the brain (may take 6 mo-1 year), from onset of clinical signs, it takes days for the animal to die
what is the most common rabies carrier in KY?
skunk
pathogenesis
transmission occurs by the bite of an infected animal, virus multiplies in the muscle tissue around the bite site, travels to the neurons, then to the spinal cord to the brain (or through the cranial nerves to the brain), incubation period may take weeks to months, once transit has started through peripheral nerves the progression is rapid, after it reaches the brain it passes centrifugally to tissues and organs and reaches the salivary glands and nasal secretions
clinical signs
*clinical signs are progressive from onset until death
poor racing performance, bizarre behavior, lameness, GI upset, shifting weight, ataxia, weakness, paralysis, urine dripping, flaccid tail and anus, depression (dumb) or aggression (furious), self-mutilation, tremors, seizures, head pressing, inability to drink (hyper phobia), increased salivation
furious rabies
animal becomes enraged, hyper excitable, fearful, aggression, hyperesthesia (increase in sensitivity to stimuli)
dumb rabies
mental depression, inappetance, head pressing, circling
differnetial diagnosis of rabies
EEE/WEE, WNV,EHV-1, hepatic encephalopathy, EPM, colic
diagnosis
no definitive ante-mortem test for rabies in animals-all need to be done after the animal is dead, clinical signs and history are suggestive but non diagnostic, in humans- ante-mortem test=saliva, CSF, serum and skin biopsies
treatment
no therapy is effective to treat rabies in any animal with clinical rabies, horses exposed to a confirmed case must be re-vaccinated immediately and observed for 45 days, herbivore to herbivore transmission is uncommon, one of the only diseases you can vaccinate for after the fact
negri bodies
most important diagnostic tissue for rabies, in the brain, may get rabies from touching the brain
prevention
annual vaccination, exposure avoidance, minimize contact with wild life as much as possible, secure garbage cans, do not leave pet food outside, rabies is rare in vaccinated individuals, if bitten the first line of defense is to decrease the viral load by washing the wound with soap and water
