RABIES CONTROL & ERADICATION PROGRAM

Ninfa R. Ambat, M.D. FPAFP

RABIES

• RNA virus; SS RNA approx. 75-80 nm diameter

• Bullet-shaped, enveloped• Rhabdovirus group• Acute viral disease of the CNS that

affects all mammals• Acute encephalitis: fatal outcome,

no effective cure

WHO

• Ranks 12th among major killer diseases.

• Around 10 million people are exposed annually.

EPIDEMIOLOGY

• Philippines: endemic disease despite availability of vaccines

• 6-8 / million population (one of the highest worldwide)

• Locally: approx. 400,000 people consult for rabies exposure annually (75% post-exposure vaccination)

• Domestic dog: 98% of human rabies

PATHOGENESIS & CLIN. MANIFESTATIONS

• Incubation period: 20-90 days; > 95% of patients will (+) with S/Sx within 6 months of exposure

• Virus remains at site of bite, undergoes amplification; crosses the myoneural junction to reach the nerve ending.

PATHOGENESIS (Incubation Period)

• Patient has no symptoms except those related to local wound healing.

• No lab tests available which can diagnose rabies.

• THE ONLY TIME WHEN VACCINATION IS EFFECTIVE!

PATHOGENESIS (Prodrome)

• 2-10 days• Virus reaches the spinal cord• Non-specific S/Sx: fever, headache,

body malaise• 1st rabies specific sx: pain or

itching or paresthesia at bite site.

PATHOGENESIS (Acute Neurologic Phase)

• 2-7 days• Virus reaches the brain, multiplies

& disseminates rapidly to the rest of the organs notably the SALIVARY GLANDS.

• Patient may die at this stage.• May present in 2 ways:

Encephalitic or “Furious” Rabies

• 80% of cases.• Hyperactive episodes: combative, (+) bizarre

behavior, agitated or apprehensive, alternating with lucid moments

• HYDROPHOBIA: elicited by giving the px a glass of H2O, (+) rxn: agitation, cringing, contraction of muscles; caused by painful contractions of laryngeal muscles upon drinking.

• AEROPHOBIA: elicited by fanning the patient; (+) rxn same as above.

Paralytic or “Dumb” Rabies

• In 20% of cases.• Starts as paralysis of the bitten area which

spreads to involve all limbs & eventually ends in respiratory paralysis.

• Most often missed: hydrophobia and aerophobia are absent.

• High index of suspicion: pxs who came in with paralysis or encephalitis of undetermined etiology. A hx of prior exposure should be elicited.

PATHOGENESIS (Coma)

• 4-10 days.• Complications start to appear.• Outcome: DEATH due to

respiratory paralysis!!!

DIAGNOSIS

• Made clinically• Pathognomonic hydrophobia and

aerophobia with history of exposure = DIAGNOSIS OF RABIES

LABORATORY WORK-UP

• RT-PCR of saliva / oral swab• Corneal imprint (FAT)• CSF exam: increase in

mononuclear cells, proteins are slightly elevated

• Post mortem samples: (+) for FLUORESCENT ANTIBODIES TEST, done in dogs

MANAGEMENT

• Therapy Mortality rate almost 100%Better prevented than treatedSpecific chemotherapy for rabies is

not availableSupportive care: IVF and sedation

(midazolam & diazepam)

PRECAUTIONS IN HANDLING RABID PATIENTS

• Rabies is communicable; a suspected case requires immediate isolation.

• Px should be restrained.• Anyone coming in direct contact with the px

must wear gloves, face mask, gown & goggles.• Special attention should be paid to the px’s

saliva, sputum, CSF & other body secretions & to the disposal of equipment that may harbor rabies virus such as foley & suction catheters.

PRECAUTIONS IN HANDLING RABID PATIENTS

• Equipment used should be sterilized at 600C for at least 30 min to kill the virus.

• Immediate hand washing with soap & water is necessary after handling the patient or his body secretions.

• These precautions should be undertaken during the entire duration of the illness.

MANAGEMENT: Requires prophylaxis

• Bites with penetration of skin.• Exposure to px’s saliva or other

potentially infectious material in direct contact with mucus membrane (oral, conjunctival or genital) or broken skin (cut, scratch, abrasion).

• Scalpel nicks or needle stick injuries if these were in contact with CSF, nervous tissue, ocular tissue or internal organs.

No prophylaxis necessary

• Contact with blood, stool• Contact with potentially infectious

material in direct contact with intact skin.

• Needle stick injuries where the needle came in contact with blood only.

• Sharing of food/drink with px.• Casual contact such as hx taking, PE,

being in the same room.

Prophylaxis should be given depending on the category of

exposure:

•Category I•Category II•Category III

Category I

• Includes sharing of food/drink with rabid px; casual contact.

• No prophylaxis is required but may give pre-exposure prophylaxis (D0, D7, D28) if desired.

Category II

• Includes licking of broken skin; superficial bites without bleeding.

• Give vaccine only.

Category III

• Bites which bleed.• Splashing or splattering of saliva or CSF

or other infectious body fluids into eyes/mouth.

• Scalpel nicks or needle stick injuries where the needle is in contact with CSF, nervous tissue, ocular tissue, internal organs, saliva or other infectious body fluids.

Category III

• Requires:VaccineRabies immune globulin (RIG)

Pre-exposure Prophylaxis

• Those who are at high risk: Veterinarians Animal handlersLab workersHospital staff (attending to rabid pxs)

Regimens

• PVRV (0.5 mL) or PDEV (1.0 mL) IM at 1 site on days 0, 7 and 28.

• PVRV (0.1 mL) or PDEV (0.2 mL) at 1 site on days 0, 7 and 28.

• Booster dose (every 1-3 years) is required for those with continuing risk.PVRV: Purified Vero Cell Rabies Vaccine PDEV: Purified Duck Embryo Vaccine

Post Exposure Treatment

• General Principles:To minimize the amount of virus at

the site of inoculation.T develop a high titer of neutralizing

antibody early & maintain it for as long as possible.

Components of Post-exposure Treatment

• Local Wound Care Immediate vigorous washing & flushing

with soap & H2O, detergent or H2O alone are imperative

Apply alcohol, tincture or aqueous solution of iodine or povidone iodine.

Anti-tetanus prophylaxis should be initiated or boosted (check immunization history). Animal bite wounds are considered tetanus prone.

Components of Post-exposure Treatment

• Local wound care Suturing of wounds should be

avoided or delayed as it may inoculate virus deeper into the wound. If suturing is unavoidable (e.g. deep face wounds) it should be done loosely. Make sure RIG is instilled deep into the wounds before suturing.

Components of Post-exposure Treatment

• Local wound care Antibiotic Prophylaxis

Administer prophylactic abx to all Category III dog bites that are either deep, penetrating, multiple or extensive. For these instances where there are no signs of infection, amoxicillin as prophylaxis may be suffice.

Components of Post-exposure Treatment

• Local wound care Antibiotic Prophylaxis

For frankly infected wounds, may give either cloxacillin or co-amoxiclav.

Other exposures (Category I or II) may be given abx only if the wound is infected.

Components of Post-exposure Treatment

• Passive Immunization (Ig) Equine Rabies Immune Globulin

(ERIG): 40 units/kg on Day 0 ANST; as much of the recommended dose as anatomically feasible should be infiltrated around the wound(s); the rest is given IM on the gluteal region.

Components of Post-exposure Treatment

• Passive Immunization (Ig) Human Rabies Immune Globulin

(HRIG): 20 units/kg on Day 0; as much of the dose should be infiltrated around the wound, the rest given IM on the gluteal region.

NOTE: HRIG is given if skin test to ERIG is (+), or with previous hx of rxn to an equine serum.

Components of Post-exposure Treatment

• Active Immunization Should be given on the deltoid

muscle (adults) & on the anterolateral thigh (young infants).

Purified Vero Cell rabies Vaccine (PVRV) 0.1 mL or Purified Duck Embryo Vaccine (PDEV) 0.2 mL intradermally @ 2 sites on days 0, 3, 7 and 1 site on days 30 and 90.

Handling of the Biting Animal

• Animal is healthy at the time of bite Observe for 14 days from time of incident. Don’t sacrifice healthy animal.Restricted to one area (caged/leashed).Examined by a vet on the last day.No signs of rabies free from rabies.

Handling of the Biting Animal

• Animal is sick at time of bite But no signs of indicative rabies,

have it confined by a vet.

Handling of the Biting Animal

• S/Sx at the time of bite during observation period, call AP sudden change in behavior (from mild to vicious

temperament or vice-versa) characteristic hoarse howl watchful, apprehensive expression of the eyes,

staring, blank gaze drooling of saliva paralysis or uncoordinated gait marked excitability and restlessness; pacing in cage if restrained, attacks objects within range, bites cat

Handling of the Biting Animal

• S/Sx at the time of bite during observation period, call AP (cont.) if at large, runs aimlessly, biting anything in

its way depraved appetite, self-mutilation in some cases, lies quiescent, biting when

provoked snaps at imaginary objects paralysis of lower jaw & tongue; inbility to

drink sudden death without assoc’d s/sx

Handling of the Biting Animal

• Rabid animal sacrificed danger to the public avoid damaging the head

• Sacrificed animal rabies diagnosis

National Rabies Control

• General Objectives To eradicate rabies & thereby declare

a rabies free Philippines

National Rabies Control

• Specific Objectives To control human & canine rabies in

confirmed endemic areas To prevent spread of rabies to non-endemic

rabies areas To areas establish a mechanism for a

Quick-Response Canine Immunization Program

To segmentally declare rabies free zones

ANIMAL BITE CENTERS…

• DLSUMC Emergency Room & OPD• Rural Health Units of municipalities• Gen. Emilio Aguinaldo Memorial

Hospital, Trece Martires City• RITM, Alabang, Muntinlupa

Canine Rabies Prevention

• Mass immunization• Dog control movement

Dog registration Compulsory leashing Stray dog control

• Rabies diagnosis & surveillance• Reduction of contact rates between

susceptible dogs• Mobilization of community participation

THANK YOU!