Rabies Virus

Rabies Virus

• Rhabdoviridae

• Lyssavirus

• unsegmented -ssRNA

• Bullet shaped

• 7 distinct genotypes

• Phylogroup 1

Classical Rabies Virus (RV-genotype 1)

Most commonly known rabies virus

Rabies Transmission

• Mesocarnivores

  • Dogs

  • Foxes

  • Raccoon dogs

  • Raccoon

  • Mongooses

  • Skunks

• Other mammals

  • Humans, Catles, Equids

  • Spillover

  • Dead end hosts

• Urban Cycle

  • Community strays

• Sylvatic Cycle

  • Wild mammals as reservoir

• Distribution

  • Asia, America, Africa, Europe (sporadic)

• Transmission

  • Saliva and broken skin (bites, scratches, licks)

Sylvatic and Urban

Cycles of RABV

Chiropteran (Bats)

Hosts of most Lyssavirus

Mesocarnivores

Hosts of RABV

Saliva and broken skin (bites, scratches, licks)

How is rabies virus transmitted?

Dead End Hosts

Other mammals can serve as hosts for RABV but they are considered what?

Epidemiology of RABV

• Dogs as main source

• Asia, Africa, America, Europe (sporadic)

• Neglected Tropical Disease

• Children as frequent victimes

• September 28 World Rabies Day

• RA 9482 The Anti-Rabies Act of 2007

Pathogenesis of RABV

Clinicopathological feature in animals of RABV

• Incubation period

  • 3 to 12 weeks

  • Rarely exceeding 6 months

• Phases / Stages:

  • PRODROMAL

    • 2 to 3 days

    • Various behaviors and symptoms

  • FURIOUS (excitement)

    • Up to a week

    • Suddenly becomes vicious and behaves erratically

  • PARALYTIC

    • Paralysis, first in the wounded limb and then in the neck and head

3-12 weeks

incubation period of RABV generally

6 months

RABV incubation period can range from days to months but it rarely exceeds ____?

Phases or Stages of RABV Disease

• Prodromal

• Furious

• Paralytic stage

2-3 days

How long is prodromal period

Prodromal in Animals

• 2-3 days

• May show various behaviors and symptoms

1 week

Furious stage can last up to ____

Furious in Animals

• Can last up to 1 week

• Suddenly becomes vicious and behaves erratically

Paralytic in Animals

• Develops paralysis

  • Wounded limb → Neck → Head

RABV Cases

• Suspected Case

  • Hypersalivation

  • Paralysis

  • Lethargy

  • Abnormal aggression

  • Abnormal vocalization

  • Diurnal (if nocturnal)

• Probable Case

  • History of bite by another animal

  • Suspect animal died within 4-5 days

• Confirmed Case

  • Via diagnostic tests

• Not a case

  • Ruled out

Clinicopathological feature in humans of RABV

• Incubation Period: 2-3 months, up to 1 year

• Viral replication in dorsal root ganglia

• Pain, Paranesthesia and Pruritus

• Short prodromal phase → Neurological

• Exposure → Incubation 20-90D → Prodromal 1-2D → Neurologic 1-4D → Death (1-7D)

2-3 months, up to 1 year

Incubation period of RABV in humans

Dorsal root ganglia

Viral replication of RABV in humans

1-2 days

Prodromal stage in humans

1-4 days

Acute neurological phase in humans by RABV

1-7 days

Death in humans by RABV

Diagnosis of RABV in Animals

• Pre-exposure

• PPE

• Samples transported in cold chain

• Frozen cold packs

• Triple packaging

• Brain

  • Thalamus

  • Pons

  • Medula

• Structure of Choice - Thalamus

• Pool of brain tissues including brainstem

• Detection of viral Ag

  • Fluiorescent Antibody Tests (FAT)

  • Direct Rapid Immunohistochemical Test (dRIT)

  • Ag ELISA

• Detection of viral replication

  • Cell culture test (RTCIT)

  • Mouse inoculation test (MIT)

• Molecular techniques

  • RT-PCR

• Serology tests

  • Virus Neutralization: FAVN and RFFIT

  • Ab ELISA

• Field Surveillance

  • Rapid Immunodiagnostic Tests (RIDT)

    • Rapid Immunochromatographic Tests (RICT),

    • Lateral Flow Devices (LFD)

Thalamus

Structure of choice in brain

Diagnosis of RABV in humans

• Ag Detection

• Virus Isolation

• Neutralizing Ab Test

• RT-PCR

• IFA

Prevention and Control of RABV

• STOP-R

  • Socio-cultural

    • Responsible dog ownership

  • Technical

    • Strengthen animal health and public health systems

  • Organizational

    • Ensure sufficient supply of vaccines

  • Political

    • Promote One Health

    • Investments in rabies elimination strategies

  • Resources

    • Create sustainable human and funding resources

• Vaccinate Program for Animals

• Animal Birth Control

• Promotion of responsible ownership

• Education Campaign

• Expansion of human

• PEP (post exposure prophylaxis)

PEP (Post Exposure Prophylaxis

• Emergency response to a rabies exposure.

• Prevents the virus from entering the central nervous system, which would invariably result in death

• Consists of:

  • Extensive washing with water and soap for at least 15 minutes

    and local treatment of the wound as soon as possible after a

    suspected exposure

  • A course of potent and effective rabies vaccine that meets WHO

    standards

  • Administration of rabies immunoglobulin or monoclonal

    antibodies into the wound, if indicated.

Categories of contact and recommend PEP

II and III

Categories requiring PEP

Rabies-Suspect Submission Flow

• Owner, Barangay, Private Animal Clinic, ABTC

• → TAHOA (Temporary Animal Holding and Observational Area)

• → TAHOF (Temporary Animal Holding and Observational Facility - IMPOUND)

Freedom from Rabies

• The World Organization for Animal Health has established standards for surveillance systems used to declare an area free from disease

  • Disease is notifiable

  • An ongoing system of effective disease surveillance has been in operation for at least 2 years without any case detection, with a minimum requirement being an ongoing early detection program to ensure investigation and reporting of rabies-suspect animals.

  • Post-disease elimination infrastructure is maintained to enable detection of disease recursion and any disease presence is reported to national and international agencies.

  • Regulatory measures for the prevention of rabies are implemented, particularly restrictions on the importation of high-risk animals from rabies-endemic countries.

National Rabies Prevention and Control Program Strategic Plan 2020-2025

• Vision

  • Rabies Free Philippines by 2030

• Goal

  • To end human deaths from dog-mediated rabies by 2027

• Activities

  • Mass vaccination of Dogs

  • Establishment of a central database system for registered and vaccinated Dogs

  • Impounding, field control and disposition of unregistered, Stray and unvaccinated Dog

  • Conduct of information and education campaign on the prevention and control of Rabies

  • Provision on pre-exposure treatment to high risk personnel and Post Exposure Treatment to animal bite victims

  • Provision of free routine immunization or Pre-Exposure Prophylaxis (P.E.P.) of schoolchildren aged five to fourteen in areas where there is high incidence of rabies as well as the encouragement of the practice of responsible pet ownership

National Rabies Prevention and Control Committee (NRPCC)

Challenges of Rabies Control in the Philippines

• Low canine vaccination coverage

• Lack of reliable estimates of the dog population

• Lack of education particularly about pet ownership

• Poor mechanism for canine rabies surveillance.

• Poor surveillance and lack of outbreak response activities

• May lead to failure in promptly removing the source of infection for both humans and other animals

• Poor rabies surveillance factors

  • The number of diagnostic facilities are limited

    • Long distance from the diagnostic facility and inadequate transportation system make it difficult for owners or bite victims to submit samples

  • The current current reporting system is not streamlined, which prevents real-time sharing of information

  • There are no guidelines or manuals for case investigation and

    response

    • No existing case management system involving human and animal sectors upon identification of a laboratory confirmed animal rabies (LCAR) case