EMmedonline

• It is caused by rhabdovirus

TRANSMISSION

• Bite of a rabid animal is the commonest route

• Contamination of mucous membrane by saliva and potentially infectious material like brain tissue

• Aerosol transmission

• Exposure while working in lab with rabies virus

• Infected organ transplant

• Contraction of rabies through consumption of raw meat or animal derived tissue has never been confirmed.

• Other contact like patting a rabid animal or contact with the blood, urine or feces of a rabid animal, does not constitute an exposure.

Incubation period: 20 to 90 days

CLINICAL FEATURE

• Fever, sore throat, chills

• Malaise, anorexia, headache

• nausea, vomiting

• cough, dyspnea

• Autonomic dysfunction: hyperthermia, tachycardia, hypertension & excessive salivation

• 50% of the cases have classic hydrophobia, in which attempt to drink water results in spasm of pharynx, larynx & diaphragm.

• Paralytic rabies is seen in 20% of the cases where paralysis is maximum in the bitten limb,diffuse & symmetric.

• Later patient develops coma, hypotension, hypoventilation, apnea, pitutary dysfunction, cardiac arrythmia, cardiac arrest & leads to death.

Diagnosis

• Isolation of viral antigen from brain tissue.

• PCR of CSF And saliva.

• CSF :Lymphocytic pleocytosis. Shows areas of increased signal abnormality in brain stem, hippocampus & hypothalamus.

MANAGEMENT OF BITE WOUNDS

GENERAL CONSIDERATIONS

• If rabies immunoglobulin is not available on first visit its use can be delayed by a maximum of 7 days from the date of first vaccine injection.

• Pregnancy & infancy are never contraindication to PEP

• Persons who present for evaluation & rabies post exposure prophylaxsis even months after having been bitten, should be dealt in the same manner as if the contact occurred recently.

• PEP may be discontinued if involved animal is a dog or cat that remains healthy for an observation period of 10days after the exposure occurred.

FIRST AID

• Immediate washing & flushing for 15min with soap & water or water alone

• Disinfection with etahnol or iodine.

• Postpone suturing if possible

• Apply antimicrobials & TT

POST EXPOSURE PROPHYLAXIS

Intramuscular Regimen

• 5 dose IM regimen : Day 0,3,7,14,28 in deltoid region or anterolateral part of thigh in childrens.

• 2-1-1 regimen may also be used. Two doses are given on day 0 over right & left deltoid muscle. Additional dose on day 7 & 21 .

Intradermal Regimen for PEP (2-2-2-0-2)

• ID is considered appropriate in settings where vaccine is short of supply as they require considerably less vaccine.

• One dose of vaccine, in a volume of 0.1 ml is given intradermally at two different lymphatic drainage sites, usually left & right upper arms, on days 0,3,7 & 28.

• Vaccine administrated intradermally must raise a visible & palpable bleb in the skin.

• Intramuscular vaccine reduces the volume of vaccine used and cost by 60-80% and is considered appropriate where vaccine or money in short supply.

• PCECV Rabipur has been proven to be safe and efficacious. (WHO recommends to use prequalified rabies vaccines that can be used by ID route.)

• In India only those anti rabies vaccine approved by DGCI for ID administration should be used for ID route.

Contraindication for Vaccine

• There are no absolute contraindications as rabies is fatal disease.

• However it may avoided as pre exposure prophylaxis in individuals with acute disorder.

RABIES IMMUNOGLOBULIN (RIG)

• It is used in category 3 exposure management.

• Infiltrate into depth of the wound and around the wound as much as possible and the remainder into anterior thigh.

• DOSE : Human RIG : 20IU/Kg; Equine RIG: 40IU/Kg

IMMUNOCOMPROMISED INDIVIDUALS

• No change in regimen

• HRIG should be received in categoriy 2 or 3 exposure .

RABIES PEP OF PREVIOUSLY VACCINATED PERSONS

• Local treatment of wound

• No RIG

• Two PEP schedules are available

  • One dose on days 0 & 3 0.5ml IM or 0.1 ml ID.

  • 4 site: 4 injections of 0.1ml distributed on each arm,thigh or suprascapular regions on day 0.

PRE-EXPOSURE RABIES VACCINATION

• Three doses of vaccine on days 0,7 & 28.

• Persons at risk should check rabies virus neutralising antibody titre every 6 mtns.

• A booster dose should be taken when titres fall below 0.5 IU/ml.

ADVERSE EFFECT OF VACCINATION

• Fever, myalgia, headache, lymph node swelling, fatigue, arthritis.

• Pain, redness, swelling.

Updated on 6/11/2016

Reference :

• WHO Guide for Rabies pre & post exposure prophylaxis in Humans. Updated 2014.

• National Guidelines on Rabies Prophylaxis. NCDC. 2015.

• http://www.who.int/mediacentre/factsheets/fs099/en/
  

• https://www.cdc.gov/rabies/transmission/exposure.html
  

Rabipur vaccine is purified chick embryo cell vaccine.