1. Unit 11: Nervous System Diseases

2. Tetanus Tetanus –Acute, highly infectious –Contagious? –Affects Humans Humans Horses Horses Sheep Sheep Swine Swine cattle cattle

3. Unit 11: Nervous System Diseases –Infectious organisms gain entrance to the body through traumatized tissue Deep wounds that seal quickly are often most problematic Deep wounds that seal quickly are often most problematic Docking, castration, shearing cuts, dehorning, etc. Docking, castration, shearing cuts, dehorning, etc. –Cause Bacterial infection Bacterial infection

4. Unit 11: Nervous System Diseases –Clinical Signs Localized infection (doesn’t go systemic) Localized infection (doesn’t go systemic) –Gives off a very powerful toxin (100x more powerful than some poisons) Passes along the nerves to the spinal cord Passes along the nerves to the spinal cord A few days to several weeks after initial infection A few days to several weeks after initial infection Stiffness moderate to pronounced Stiffness moderate to pronounced –“lock-jaw” –Ears, tail, eyes retracted

5. Unit 11: Nervous System Diseases Rapid symptom development often = death Rapid symptom development often = death Recovery usually >50% Recovery usually >50% –Prevention Thorough cleansing of wounds Thorough cleansing of wounds Antiseptic procedures Antiseptic procedures –Docking, castrating, surgeries, etc. Immunity can be raised w/ a toxiod or antitoxin Immunity can be raised w/ a toxiod or antitoxin –Toxoid Injection of neutralized tetanus toxin to stimulate the body’s immune response Injection of neutralized tetanus toxin to stimulate the body’s immune response

6. Unit 11: Nervous System Diseases –Antitoxin Concentrated serum w/ tetanus toxin antibodies taken from another animal administered as an injection Concentrated serum w/ tetanus toxin antibodies taken from another animal administered as an injection –Some vaccines also available –Treatment Larges doses of tetanus antitoxin, sedatives, and care Larges doses of tetanus antitoxin, sedatives, and care Reopen site of infection, clean, drain Reopen site of infection, clean, drain Antibiotic therapy Antibiotic therapy

8. Unit 11: Nervous System Diseases Pseudorabies Pseudorabies –Acute viral infection of pigs & cattle, sometimes sheep –Non-contagious in cattle, highly contagious in swine –Spread by bites from infected hogs –Cause Herpes virus Herpes virus Swine are long-term carriers Swine are long-term carriers

9. Unit 11: Nervous System Diseases Disease waits for stress periods to show itself Disease waits for stress periods to show itself State blood testing is required for swine transport State blood testing is required for swine transport –Can travel between herds ~2 mi –Clinical Signs Cattle will have usually been associated w/ swine at some juncture Cattle will have usually been associated w/ swine at some juncture Intense itching at the site of infection Intense itching at the site of infection Newborn pigs can go from normal to coma in 6-24 hrs. Newborn pigs can go from normal to coma in 6-24 hrs.

10. Unit 11: Nervous System Diseases Older swine Older swine –Show some CNS symtpoms –Incoordination, paralysis, muscle spasms, etc. –Mild fever, depression, finicky appetite –Abortions in pregnant sows, dead or mummified pigs if they don’t abort –Infected breeding females often hard to settle –Prevention Vaccinaton Vaccinaton –No Treatment available

11. Unit 11: Nervous System Diseases Equine Encephalomyelitis Equine Encephalomyelitis –Infectious disease spread by insects –Characterized by nervous disorders and high mortality –Usually individual cases, unless conditions become favorable for high populations of mosquitoes

12. Unit 11: Nervous System Diseases –Cause Viral Viral 3 types 3 types –Western, Eastern, Venezuelan –Western & Venezuelan most common in our area Birds help develop the disease Birds help develop the disease –Clinical Signs Affects CNS Affects CNS Nervousness, depression, impaired vision, etc. Nervousness, depression, impaired vision, etc.

13. Unit 11: Nervous System Diseases Lay on side and gallop Lay on side and gallop Mild cases often recover, acute cases often die Mild cases often recover, acute cases often die –50% mortality for Western –90-100% for Venezuelan –Prevention Vaccination Vaccination Mosquito control methods Mosquito control methods Discourage bird roosting around the barn Discourage bird roosting around the barn

14. Unit 11: Nervous System Diseases –Treatment Not very effective because of the rapid nature of the disease Not very effective because of the rapid nature of the disease Mostly supportive therapy Mostly supportive therapy Scrapie Scrapie –Common in sheep and goats –Contagious Transmissable agent can withstand boiling & exposure to chemical agents Transmissable agent can withstand boiling & exposure to chemical agents

15. Unit 11: Nervous System Diseases –Can occur more frequently in certain breeds or families Question of heritability Question of heritability Some Suffolk breeders DNA test Some Suffolk breeders DNA test –Clinical Signs 18-24 mo incubation period 18-24 mo incubation period Progressive wt loss, hind end weakness Progressive wt loss, hind end weakness First signs: First signs: –Nervousness, restlessness, excitability, itching, patches of wool rubbed off

16. Unit 11: Nervous System Diseases No loss of appetite, normal temp No loss of appetite, normal temp –Prevention No vaccine No vaccine Quarantine and slaughter for control Quarantine and slaughter for control –No treatment

17. Unit 11: Nervous System Diseases BSE BSE –Slow degenerative disease of the CNS –Unknown cause –Infects brain and spinal tissue –Related to an infectious human disease –Not transmitted in milk –Can be passed in meat?

18. Unit 11: Nervous System Diseases –No know treatment, or control –Prevention Testing Testing Quarantine Quarantine