10 Ruminant Neurologic Disease II: Viral Neurological Diseases of Ruminants

Raccoons and skunks

What are the main vectors for rabies in the United States?

Lyssavirus genus, Rhabdoviridae family

What is the genus and family of rabies?

1. *constant straining* to the point of having or almost having a rectal prolapse

2. hindlimb ataxia which starts as weakness and progresses to paralysis = severe knuckling

3. self mutilation

4. salivation, bellowing, aggressiveness

What are some red flag signs of rabies infections in cattle?

Cerebral/Furious, Brainstem/Dumb, SpinalCord/Paralytic

What are the 3 forms of rabies in cattle?

Cerebral or furious form

Which form of rabies in ruminants typically presents as aggressive behavior, photophobia, hyperesthesia, straining, and convulsions?

Brainstem or dumb form

Which form of rabies in ruminants typically presents with depression and dementia with ataxia, excessive drooling, and pharyngeal paralysis?

Spinal Cord or paralytic form

Which form of rabies in ruminants typically presents with progressive ascending paralysis?

Negribodies in neurons (may not be present if disease is only in spinal cord)

What are you looking for when doing a laboratory confirmation diagnosis of rabies?

10 days

How soon does death happen in rabies after onset of clinical signs in ruminants?

Rabies virus in saliva of infected dog bites cattle --> rabies virus enters motor neuron endplate --> replicates in muscle --> rabies multiplies in spinal cord and travels to brain

What is the pathogenesis like for rabies in ruminants?

Grave

What is the prognosis like for rabies in cattle?

Milwaukee protocol (vaccinate after exposure, booster 3 and 8 weeks after)

What treatment can be used for rabies in cattle but is controversial?

Virus present in saliva for up to 5 days before sigs are evident

Dogs shed rabies about 10 days prior to clinical signs, what about cattle?

Virus introduced to bite wounds, open cuts, or onto mucous membranes

How do cows get rabies?

From drinking her milk = no. But the calf would probably get it anyway from the mom grooming it

If a cow had rabies, would her calf also get rabies by drinking her milk?

RABIES

Unrelenting tenesmus (intense straining to defecate), weak rear end, and behavior change make you consider...?

Rabies virus

Sodium hypochlorite, ethanol, iodine, formaldehyde, phenol, and detergents can all inactivate WHAT?

Pseudorabies (Mad Itch, Aujeszky's Disease)

This is an acute viral encephalitic disease of ruminants primarily characterized by severe pruritis which is VERY rare in the U.S.

Family: Alphaherpesvirus

Genus: Varicellovirus

What is the genus and family of Aujeszky's Disease (Pseudorabies)?

HIGHLY

Pseudorabies is *highly/minimally* contagious.

Domestic and feral swine

Most mammals are susceptible to pseudorabies, but which is the natural/primary host that can become latent carriers?

SEVERE PRURITIS, or even sudden death without obvious signs

What is the BIGGEST clinical sign with pseudorabies?

Pseudorabies

A cow has dermal abrasions, swelling and alopecia at the inoculation site of a virus, bloat, stamps the feet, is salivating and chewing the tongue. You have notice the cow seem extremely itchy. What do you think?

Pseudorabies

This virus postmortem shows subtle lesions: serous or fibrinonecrotic rhinitis, pulmonary edema, congestion, congested/hemorrhagic lymph nodes, and necrotic foci in the organs

*YES*

Is pseudorabies reportable?

Submit an area of intense pruritis for testing, clinical signs are suggestive

How do you diagnose pseudorabies?

Horses

Which animal is resistant to pseudorabies?

FALSE = no effective treatment for pseudorabies

TRUE OR FALSE: pseudorabies can be treated with a vaccine

Proximity to swine means you need to add pseudorabies to the differentials list

What do you have to keep in mind when an animal seems rabid, but there are pigs on the farm?

4-7 days incubation, death in 1-2 days

What is the incubation period like for pseudorabies? How about the duration of illness?

The south (texas, florida, georgia, etc)

Where does pseudorabies seem to be a concern right now in the U.S.?