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all about rabies
epidemiology of rabies,
pathogenesis of rabies,
clinical features of rabies,
treatment of rabies,
prevention of rabies,
rabies virus,
post exposure prophylaxis,
rabies in dogs

Published in: Health & Medicine, Technology
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  1. 1. Vishnu narayanan
  2. 2. DEFINITION• A/c,highly fatal disease of CNS• Caused by Lyssavirus type 1• Zoonotic disease of warm blooded animals• Transmitted by bites of rabid animal• Long and variable IP with short period of illness• no treatment,only prevention
  4. 4. Problem statement• Enzootic as well as epizootic disease• Occurs in more than 100 countries and territories• Potential threat to more than 3 billion people• Incidence --35,000-50,000deaths/Year (WHO) 20,000deaths/yr in India 24,000deaths/yr in Africa• Age- most common in children below 15years• Sex- 15 million people receive rabies prophylaxis annually with majority males
  5. 5. Rabies free areas• Australia• New zealand• Taiwan• Cyprus• Iceland• Ireland• Japan• U.K.• Islands of western pacific• Liberian peninsula• Finland• Norway• Sweden• Andaman nicobar• Lakshadweep
  6. 6. AGENT-RABIES VIRUS• Rhabdovirus• Lyssavirus-type 1• Bullet shaped virus• Size is 180 x 75 nm• Has Lipoprotein envelop• Knob like spikes /Glycoprotein G• M protein layer• Genome- unsegmented,Linear, neg ative sense RNA
  7. 7. • Surface spikes composed of Glycoprotein G• Produces Pathogenicity by binding to Acetyl choline receptors in the neural tissue• Stimulate T lymphocytes Cytotoxic effect.• Also has hemagglutinating activity
  8. 8. Rabies viruses are sensitive to common Chemicals• The virus is sensitive to Ethanol Iodine Soap / Detergents Ether, Chloroform, Acetone Destroyed at 500 c in 1 hour at 600 c in 5 minutes.
  9. 9. Types of Rabies virus STREET VIRUS FIXED VIRUS Definition: the virus Definition: the virus recovered from which has a short, fixed naturally occurring and reproducible cases of rabies is called incubation period is “street virus” called “fixed virus Sources: it is naturally Sources: it is prepared occurring virus. It is by repeated culture in found in saliva of brain of rabbit such that infected animal. its I.P. is reduced &(continue) fixed
  10. 10. Features Features1. It produces Negri 1. It does not form Negri bodies bodies2. Incubation period is 2. Incubation period is long i.e. 20 to 60 constant between 4-6 days days3. It is pathogenic for all 3. It can pathogenic for mammals humans under certain conditions4. Cannot be used for 4. Is used for preparation of preparation of antirabies vaccine vaccine
  11. 11. RESERVOIR OF INFECTION1) URBAN RABIES:• From Dogs and cats.• 99% cases in india• A single infected dog capable of transmitting over an area of 40km
  12. 12. 2)WILDLIFE RABIES• SYLVATIC RABIES• Unidentified reservoir of infection• Foxes,jackals,hynas,skunks etc• Enzootic in south america by mongoose• Transmit infection among themselves and to dogs and man
  13. 13. Rabid Bat eared Fox
  14. 14. 3)BAT RABIES• Latin american countries,USA• Vampire bats-feed on blood of man and animals• Found from mexico to northern argentina• Cause havoc to cattle population• Not repotrted in india• Constant source of infection to man and animals• Transmission by bites and aerosols
  15. 15. Source of Infection• Saliva of Rabid animal• Dogs and cats-virus in saliva 3-4 days before clinical symptoms• Variable in quantity
  16. 16. Carrier state• Serological survey-anti rabies antibody in a proportion of unvaccinated animals• Dogs living for years with virus isolated from saliva,yet no record of transmission• Asymtomatic animals-unlikely to infect man
  17. 17. Host Factors• All warm blooded animals including man.• Rabies in man is a dead-end infection.• People at risk-lab workers, veteinerians, dog handlers, hunters, etc
  18. 18. Mode of Transmission1. Animal bites2. Licks3. Aerosol4. Person to person
  19. 19. INCUBATION PERIOD:• Normally 3 - 8 wks• May be short that is 4 days or may be prolonged for years.• Depends on-site of bite Severity of bite Number of wounds Amount of virus injected Species of biting animal Protection provided by clothing Treatment taken
  20. 20. Centripetaltransmission Centrifugaltransmission
  21. 21. PATHOLOGICAL LESIONS IN CNS• Mild inflammatory changes neuronal dysfunction• Mononuclear inflammatory inflammation• Degenerative changes not prominent• Neuronophagia-observed ocassionally• Microglial nodules-BABES NODULES• Pathognomonic lesion-NEGRI BODIES
  22. 22. • NEGRI BODIES• EOSINOPHILIC CYTOPLASMIC INCLUSIONS in brain neurons• Randomly oriented rabies virus nucleocapsids embedded in the matrix• Seen mainly in purkinje cells of cerebellum pyramidal cells of hippocampus• Absence of negri bodies-not an exclusion to rabies
  23. 23. Symptoms• Headache, fever, sore throat• Nervousness, confusion• Pain or tingling at the site of the bite• Hallucinations• Hydrophobia• Paralysis• Coma and death
  24. 24. Clinical Findings• Bizarre behavior.• Agitation• Seizures.• Difficulty in drinking.• Patients will be able to eat solids• Afraid of water - Hydrophobia.• Spasms of Pharynx produces choking• Death in 1 -6 days.• Respiratory arrest / Death / Some may survive.
  25. 25. STAGES OF RABIES INFECTION1 – Non specific prodrome2 – Acute neurologic encephalitis3 – Coma4 - Death
  27. 27. 1. Non specific prodrome 1 - 2 days  1 weekFever, headache, sore throatAnorexia, nausea, vomitingAgitation, depressionPain/tingling sensation at bitten siteDue to infection of dorsal root or cranial sensory ganglia.
  28. 28. 2 Neurologic phase
  29. 29. Encephalitic rabies• Fever, confusion, hallucinations, combativeness,• Muscle spasms, hyperactivity, seizures.• Autonomic dysfunction hypersalivation, Excessive perspiration, gooseflesh, pupillary dilation, Priapism.• Hyperexcitability followed by periods of complete lucidity• Hydrophobia and aerophobia• “Foaming at the mouth”• Due to dysfunction of infected brainstem neurons• Severe brainstem damage coma death
  30. 30. COMPLICATIONS OF ENCEPHALITIS• Disturbance in water balance• Noncardiogenic pulmonary edema• cardiac arrhythmias• myocarditis.
  31. 31. Paralytic rabies• Early and prominent muscle weakness,• Quadriparesis and facial weakness.• Sphincter involvement is common,• Sensory involvement is usually mild.• Guillain-barré syndrome is a common misdiagnosis.• Patients survive a few days longer• Multiple-organ failure even with aggressive supportive care.
  32. 32. Rabies can present as Grave condition
  33. 33. Majority will succumb to Disease
  34. 34. DIAGNOSIS1. History2. Signs and symptoms3. Clinical examination4. Detection of antigen by taking skin biopsy using immunofluorescence5. virus isolation from saliva & other secretions.6. CSF analysis and CT scan7. ELISA8. RT-PCR9. DFA testing10. Negri bodies
  35. 35. DIFFERENTIAL DIAGNOSISOther viral encephalitisRabies hysteriaLandry/Guillan-barre syndromePoliomyelitisAllergic encephalomyelitis ( rabies vaccine )
  36. 36. TREATMENT• No established treatment for rabies.• Recent treatment failures of antiviral therapy,ketamine, and therapeutic coma-milwaukee protocol• Expert opinion to be sought before any experimental therapy• A palliative approach may be appropriate for some patients.
  37. 37. Case management• Isolation of the patient• Post-exposure prophylaxis• Antianxiety drugs and sedatives• Muscle relaxants with curare like action• Ensure hydration and diuresis• Cardiac and respiratory support
  38. 38. Ist Vaccine for Rabies• Prepared by Pasteur by drying various periods pieces of spinal cord of Rabbits infected with fixed virus• 1885 Joseph Meister 9 year boy vaccinated 13 injections were given• Patient saved
  39. 39. 1.POST-EXPOSURE PROPHYLAXIS• To reduce viral load by elimination from the wound• To neutrilise the virus at site of entry• To prevent nerve infection• To induce systemic immunity• Includes -1.wound treatment 2.observation of the animal 3.immunization 4.advice to patient
  40. 40. Category of bites (WHO)Category • Licks on unbroken skin • Touching/ feeding animals ICategory • Nibble, cuts, scratches without oozing of blood IICategory • Licks on mucous membrane or broken skin III • Bites with breach of skin, bleeding
  41. 41. Recommended TreatmentCategory • None ICategory • Local Rx of wounds II • Anti rabies vaccine • Local Rx of woundsCategory • Anti rabies vaccine III • Rabies immunoglobulin
  42. 42. WOUND MANAGEMENTCleansing-with soap and water (minimum 10min) punctured wound irrigated with cathetersChemical treatment-virucidal agents- 70%alcohol, povidine iodine, tincture iodine, etcLocal adminisration of rabies antiserumSuturing -done after 24-48hrs with antiserum locallyAntibioticsImmunization against tetanusWound not to be dressed or bandaged
  43. 43. OBSERVATION OF ANIMAL• To determine the risk of infection• For 10 days• Look for any abnormal behavior of animal• If animal died, look for negri bodies• If possible do FRA test• If animal healthy and alive after 10 days-no treatment• If animal cannot be observed-suspected to be rabid
  44. 44. IMMUNIZATIONINDICATIONS1. Immediately started when a person bitten,scratched or licked by animal2. If animal not available for observation3. Bites4. If animal is suspected to be rabid5. If the animal is confirmed rabid6. Person drinking raw milk of rabid animal7. If patient comes late
  45. 45. ACTIVE IMMUNIZATION• Antirabies vaccination• For both category 2 and 3PASSIVE IMMUNIZATION• Rabies immunoglobilins• For category 3
  46. 46. ADVICE TO PATIENT• Treatment-correctly and completely• Avoid steroids,spicy food,spirit,smoking,strain during treatment period
  47. 47. Vaccines for immunization It is fluid or dried preparation of Rabies “Fixed” virus grown in the Neural tissue of Rabbits, Sheep, Goats, Mice or RatsOR in embryonated duck eggsOR in cell culture
  48. 48. Antirabies vaccines1. Nerve tissue vaccines2. Duck embryo vaccine3. Modern tissue/cell culture vaccine
  49. 49. 1.Nerve tissue vaccinea) BPL-vaccine• Prepared by inoculating fixed virus into nervous system of sheep,goat,rabbit,mice• Killed on 7th or 8th day, brain removed• 5% emulsion prepared with saline• Virus killed by BPL• If sheep is employed-semple vaccine• Dosage schedule-1ml to 5ml,s/c around the umbilicus,7-10 days• Demerits-killed vaccine only 50%effective slow immunity, which lasts for only 6 months neuroparalytic reactions• Not recommended by WHO
  50. 50. b) Suckling mouse vaccine• Prepared by inoculating fixed virus into brain of young suckling mice less than 9 days old• Safer than semple vaccine• No neuroparalysis• Extensive use in latin america• Not recommended by WHOGovt of india stopped nerve tissue vaccine productionby 2004
  51. 51. 2.Duck embryo vaccine• Flury’s vaccine• Vaccine free of neuroparalytic disorder• Causes allergic reactions in egg protein sensitive individual• Not used in india
  52. 52. 3.Cell culture vaccine• Great advance in rabies prophylaxis• More potent,safer,stable,effective• Less reactogenic• Less dose required, painless injection, irrespective of age and sex• Freeze dried vaccines supplied with diluent and syringe• Includes HDCV PCEC-V second generation vaccines PVRV
  53. 53. HUMAN DIPLOID CELL VACCINE• By propogating fixed rabies virus in human diploid fibroblast cells• Generally safe and highly potent• Available as liquid vaccine• Gold standard anti rabies vaccine• Costly
  54. 54. SECOND GENERATION VACCINES• Purified chick embryo cell vaccine-from chick embryo fibroblast with diluent-sterile distilled water• Purified vero-cell rabies vaccine-from vero cells with sterile normal saline as diluent• Less cost,highly potent• WHO reference vaccine
  55. 55. DOSAGE SCHEDULES1. INTRAMUSCULAR SCHEDULE• 2 types• Essen schedule• Zagreb schedule• Site-intramusclarly-deltoid/thigh
  56. 56. • Essen schedule• First 3 doses to be given at correct date• Dose-1/0.5 ml in deltoid• Stopped after 3 doses if bitten animal remain asymptomatic after 10 days
  57. 57. • Zagreb schedule
  59. 59. Anti-rabies serum• Equine Anti Rabies serum: 40 IU/kg• Human rabies immunoglobin : 20 IU/kg• Recommended dose around the wound and rest in IM on 0 day• Booster doses are essential whenever anti rabies serum is given with the vaccine• ARG-local viricidal/neutrilising effect
  60. 60. 2.PRE-EXPOSURE PROPHYLAXIS• Done in persons who have high risk of repeated exposures. Animal Handlers Wildlife officers Veterinarians Lab: staff working with rabies virus• Cell-culture vaccine 1ml I/M OR 0.1ml I/D ( 0,7& 28day)• Booster dose every 2 years
  61. 61. 3.PEP FOR PREVIOUSLY VACCINATED PEOPLE• If antibody titre unknown or bite severe-1ml HDC vaccine 0,3,7 days• If antibody titre>0.5IU/ml and bite not severe-0,3 days• Rabies immunoglobulin not to be administerd• if re-exposure within 1 yr of PEP-no treatment• If re-exposure after 3 yrs-full schedule PEP
  62. 62. RABIES IN DOGS
  63. 63. • INCUBATION PERIOD:• 3-8 wks.• Range from 10 days to 1year• CLINICAL FEATURES:• Rabies in dogs may manifest itself in two forms.• Furious rabies• Dumb rabies
  64. 64. a. Furious rabies- Typical mad-dog syndromei. Change in behavior.ii. Running amuck.iii. Change in voice due to paralysis of laryngeal muscles.iv. Excessive salivation & foaming at the angle of the mouth.v. Paralytic stage
  65. 65. b. Dumb rabies.i. No excitative or irritative stageii. Predominantly paralytic.iii.Dog withdraws itself from being seen or disturbed.iv. Elapses into a stage of sleepiness and dies in about 3 days.
  66. 66. • DIAGNOSIS1. Fluorescent antibody test2. Microscopic examination3. Mouse inoculation test4. Corneal test
  67. 67. IMMUNIZATION OF DOGS• Most important weapon in rabies control• 80-90% dog popoulation-accesible for vaccination• Mass vaccination-effective tool• Primary immunization-age-3 to 4 months• Booster dose-regular interval based on type of vaccine
  68. 68. VACCINES FOR DOGS1. BPL inactivated nervous tissue vaccine• 20% suspension of infected sheep brain• Dose-5 ml• Revaccination-after 6 months followed by every year• Low efficacy-not recommended
  69. 69. 2. Modified live virus vaccine• 33% chick embryo suspension infected with modified virus• Dose-3ml by single injection• Booster-every 3 years• Raksharab,Nobivac-R,Robigen,Rabisin
  70. 70. URBAN RABIES CONTROL• Elimination of stray and ownerless dogs• Swift mass immunization of dogs• Registration and licensing of all domestic dogs• Restraint of dogs in public places• Immediate destruction of dogs and cats bitten by rabid animals• Quarantine for about 6 months of imported dogs• Health education of people• Oral vacine baits-succesful control of wildlife rabies,particularly fox
  71. 71. RABIES CONTROL UNITS IN INDIA• Launched by agriculture ministry of india in 6th five year plan aiming 100%rabies free india by 13th 5 year plan• 30 rabies control units where set up• Overall charge-senior officer of animal husbandry dept• Each unit-veterinary surgeon,supervisor,10 dog catchers• Each unit provided with a diesel van, cold storage system for vaccines, equipments for catching dogs• Immunization and sterilization of dogs• No merciless killing after prevention of cruelty against animals act was implemented• Only rabid and seriously ill dogs are killed
  72. 72. Worlds Rabies Day (on September 28)• World Rabies Day is a cooperative global event planned to reduce the suffering from rabies. This day celebrates Dr. Louis Pasteur’s vision of a rabies free world.