1. Rabies Causative agent: Rabies virus
Lyssavirus
Enveloped ssRNA
Spiked bullet shaped virus
Virus multiplies in brain forming Negri bodies

2. Signs & Symptoms Pain and itching at site of infection
Fever, headache, myalgia, sore throat, fatigue
Progress rapidly to secondary symptoms
Encephalitis, agitation, confusion, hallucinations, seizure, increased sensitivity to light and touch, coma
Increased salivation and difficulty swallowing
Results in frothing of mouth
Hydrophobia occurs in 50% of cases
About 50% of patients die within 4 days

3. Virus enters through bite
Attaches to skeletal muscle cells triggering endocytosis
Pathogen moves across neuromuscular junction into nerve cell and travels to CNS
Slow moving so long incubation period
1-2 months up to several years
Viruses travel back to the salivary glands and are secreted in saliva

4. Epidemiology Zoonotic
Skunks, raccoons and bats considered chief reservoir
75% of human cases linked to bat bites
0 to 4 reported cases in US annually

5. Prevention Treatment Vaccination of domestic animals and Vets
Wash wound immediately and thoroughly
apply antiseptic
Treatment
Risk lowered if vaccine administered as soon as possible
Interferon may be applied to wound
No effective treatment for rabies
Only six known survivors of disease

6. Viral Encephalitis Causative agent Arboviruses Zoonotic diseases
mosquitoes
Zoonotic diseases
Horses, birds and rodents
West Nile encephalitis, LaCrosse encephalitis, WEE, EEE, VEE, St. Louis encephalitis

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8. Signs & Symptoms 3-7 day incubation period
Characterized by mild flu-like symptoms
Fever; headache; vomiting
One or more nervous system abnormalities
Disorientation, localized paralysis, deafness, seizures or coma

9. Only minority infected develop encephalitis
Others may develop viral meningitis
Most reported human cases in immunosuppressd individuals
Elderly and very young
Healthy immune system typically fights off virus with only mild flu-like symptoms

10. Viruses multiply at site of bite and in local lymph nodes
viremia
Virus crosses blood-brain barrier
Damages neurons
Causes extensive damage to brain tissue in severe cases
Progression of disease halted by neutralizing antibody
Mortality ranges from 2% to 50% depending of type of infecting agent and host

11. Epidemiology Disease are all zoonoses
Maintained naturally in birds and rodents
Humans are accidental hosts
LaCrosse encephalitis usually causes most reported cases

12. West Nile an emerging disease in US
Appeared in New York in 1999

13. Prevention Treatment Eliminate vector habitat
Avoiding outdoor activities at night
Windows and porches properly screened
Use insect repellents and insecticides
Vaccine available for horses
Treatment
No proven antiviral therapy