Rabies

1. Rabies

2. Rabies is a deadly disease and almost all who get the disease die. There is NO CURE for the disease even today. • Rabies can affect any mammal.

3. FACTS ON RABIES • 50% of the deaths due to Rabies are among children under 15 years age. • 20000 people die of rabies in India every year (1 every ½ hour). • 17.4 million people are bitten by animals every year in India (1 every 2 seconds).

4. When to say rabies free • Defined as one which no case of indifenously acquired rabies has occurred in man or any animal species for 2 yrs. • Rabies free – Australia, Ireland, Japan, New Zealand

5. Epidemiological determinants • Agent factor- lyssavirus type 1 • Antigens – • surface glycoprotein • Internal nucleoprotein

6. Serial brain to brain passage of virus in rabbits • Street virus- • Virus recovered from naturally occurring cases • Incubation period varies from 20 – 60 days • Forms negri bodies on intra cerebral inoculation • Fixed virus – • Incubation period is reduced(4-6 days) • Do not form negri bodies • Used for vaccine production

7. Source of infection- to man – saliva of rabid animals • In USA- bats • In India- Dogs • Incubation period – variable • 1-3 months(but varies from 7 days to years) • Short incubation period: if bites are on face, neck head

8. Pathogenesis Centripetal spread Centrifugal spread

9. Rabies in man • 80 -90% - hydrophobia • Prodromal stage: • head ache, tingling and numbness at the site of bite • Stage of excitement: • Sensory system-irritable, anxious, nervous • Motor system- tone & spasticity, exaggerated reflexes • Sympathetic system- lacrimation, salivation, temperature, pulse

10. Stage of paralysis: • Paralysis of muscles of deglutition • Later stages – • Change in voice, frothy saliva, hyper salivation, anxious look, fear of death. • Respiratory paralysis , asphyxia, cardiac arrest , death

11. Lab diagnosis • Ante mortem- • Skin biopsy along the hair line of neck- fluorescent antibody test (FAT) • Post mortem- • Biopsy of brain- microscopy for negri bodies(FAT)

12. Treatment • No specific treatment • Case management: • Pt should be isolated in quite room

13. Prevention of human rabies • Post exposure prophylaxis • General considerations • Local treatment of wound • Immunization • Pre exposure prophylaxis

14. General consideration: • Aim – to neutralize the virus before it enter nervous system • Every instance should be treated as an emergency • Local treatment of wound • Cleansing • Chemical treatment • Sututring • Antibiotics & anti tetanus measures

15. Immunization • Cell culture vaccine[CCV] • Embryonated egg based vaccine[EEV] • Shelf life ≥ 3 yrs • Temp: + 2oC to + 8oC • Dose : ≥2.5 IU per single IM dose

16. Categories of wound:

17. Vaccination schedule • Intra muscular regimen: • Dose : 0.5 ml / 1.0 ml • Site : Deltoid / anterolateral part of thigh(child < 2yrs) • 5 dose regimen(Essen regimen) • 4 dose regimen(“2 - 1 - 1” or Zagreb regimen)

18. Intra dermal regimen • 1 intradermal dose = 1/5th of intramuscular dose • Previously Vaccinated Individuals:

19. Rabies Immunoglobulin (RIG) : • Equine (ERIG)- 40 IU/kg body weight • Human (HRIG) -20 IU/kg body weight • Site: Infiltrated into and around the wounds

20. Pre Exposure Vaccination • People at high risk of exposure such as those working in rabies diagnostic or research laboratories • Veterinarians, animal handlers (including bat handlers), animal rehabilitators and wildlife officers • People (especially children) living in or traveling to high - risk areas. • Dose: • IM- 0.5 ml / 1.0 ml • ID- 0.1 ml

21. Rabies in dogs • Incubation period : ranges from 3-8 weekss • Clinical picture: • Furious rabies • Dumb rabies • Lab diagnosis: • Fluorescent antibody test • Microscopic examination • Mouse inoculation test • Corneal test

22. Vaccination • Age of immunization: 3-4 months of age • BPL inactivated nervous tissue vaccine /Single dose • Dose : • 5 ml for dogs • 3ml for cats • Revaccination : after 6 months and subsequently every year.