Epidemiology Mode of transmission Symptoms Vaccination Immediate survey

1. BY Rasha Mohammed Sultan
Under the supervision of:
Dr. Mohammed Al-Hakamy
Community medicine
Faculty of Medicine
Ibb university
25-08-2022
RABIES

2. WHAT IS RABIES?
 Acute highly infectious viral disease of the nervous system (brain &
spinal cord) caused by lyssa virus type 1.
 Zoonotic disease, mainly of the carnivorous animals, specially the
dogs as enzootic.
 Mode of transmission: accidental bite or lick of the rabid animal
 Characterized by long incubation period, short period of illness and
hydrophobia (fear of water) → severe painful spasms of deglutition
followed by respiratory paralysis, delirium, asphyxia, & death!
 There is no treatment or cure anywhere in the world. Prevention is
the only intervention.

3. EPIDEMIOLOGY
Rabies is estimated to cause
59 000 human deaths
annually in over 150 countries,
with 95% of cases occurring in
Africa and Asia.
99% of rabies cases are dog-
mediated and the burden of
disease is disproportionally
borne by rural poor populations,
with approximately half of cases
attributable to children under
15 (incidence 5 times more
than adults).
About 327,000 people would
die from rabies in Africa & Asia
each year.
A: Human deaths from rabies;
B: Death rates per capita (per 100 000 population);
Countries shaded in grey are free from canine rabies
(WHO Expert consultation on rabies TRS n°1012, 2017)

4. RABIES IN YEMEN
 Country status: Endemic
 Human rabies death/year: 148
 Dog vaccination coverage: 18.50%
 Postexposure prophylaxis treatments/year: 20,340
 Rabies remains a worrying health problem in Yemen, with a higher percentage of cases reported
among children and males. The annual incidence of animal bites and rabies exposure was 50 and
14 per 100,000 population, respectively, and the annual mortality rate was 2 per 1000,000
population.

6. ETIOLOGY:
Causative agent: RNA virus, a Lyssa virus
type 1, belonging to rhabdoviridae family.
It is a bullet shaped neurotropic virus.
Rabies virus particles contain two distinct, major
antigens :
1.Glycoprotein (G protein) antigen from the
virus membrane and
2. An internal nucleoprotein antigen.
• The glycoprotein seems to be the only antigen
capable of inducing the formation of virus-
neutralizing antibodies.
• The virus is excreted in the saliva of the affected
animals.

7. FIXED VIRUS
• Avirulent to human beings (lost pathogenicity on human beings
but retains antigenicity).
• Incubation period is reduced and fixed, i.e. 5 to 6 days
• These advantages of the fixed virus (seed virus) are made use of
in the preparation of the vaccine!

8. RESERVOIR OF INFECTION
Raccoon
Fox
Dogs
Bats
Skunk
 All warm blooded animals,
including human beings, are
susceptible to rabies.
 Rabies in man is a dead-end
infection, and has no survival
value for the virus.

9. The rabid animal is infectious to others
during:
1.The last 3 to 5 days of incubation
period and also during
2.the entire period of illness, which is of
about 8 to 10 days.
Total period of infectivity is about 12 to 15
days.
The rabid animal remains
infectious till it dies.
Human cases are potentially infectious
during the period of illness.
All warm blooded animals including
human beings are susceptible.
However not all the persons bitten by
rabid animals will get the disease, but only
15 to 20 percent will get the
disease, because the virus is not excreted
continuously but intermittently in the
saliva of rabid animals.
But among those who get the disease,
mortality is 100 percent.
Period of infectivity Susceptibility

10. Usually it varies from 3 weeks to 3 months.
But it can vary from 15 days to 1 year.
The incubation period is so variable. It
depends upon the following factors:
1. Site of the bite,
2. Severity of bite,
3. Species of the biting animal,
4. Richness of the nerve supply,
5. Amount of saliva deposited,
6. Protection through clothes, &
7. Partial treatment taken if any.
INCUBATION PERIOD
MODES OF TRANSMISSION
 The disease is transmitted from animal
to animal and from animal to human
being by the lick or by the
bite of a rabid animal.
 Rabies in man is a ‘Dead end
disease’.

11. Centripetal
transmission:
spread of the virus
from peripheral
nerves to CNS.
Centrifugal
transmission: spread
of the virus back to
peripheral nerves.

12. Clinical features
Acute neurologic period
1. Hyperactivity
2. Excessive salivation
3. Hydrophobia: a distressing
symptom characterized by
an unquenchable thirst, an
inability to swallow, and
panic when presented with
fluids to drink.
4. Extreme sensitivity to light
(photophobia)
5. Confusion and Aggression
(including thrashing and
biting)
6. Hallucinations & Seizures

13. How is rabies diagnosed?
A clinical diagnosis of hydrophobia can be made
on the basis of history of bite by a rabid animal
and characteristic signs and symptoms.
Rabies can be confirmed in patients early in the
illness by antigen detection using
immunofluorescence of skin biopsy, and by
virus isolation from saliva and other secretions..
Neutralizing antibodies are not usually detectable
in serum or CSF before the eighth day.

14. Management of Hydrophobia Case
There is no treatment or cure for hydrophobia.
Prevention is the only intervention.
Symptomatic treatment with supportive treatment and sedation can ensure
peaceful death😢 to the victim:
1. Admission in a quiet room of a hospital (usually at the Isolation hospital).
2. Sedatives, antipyretics, analgesics, antihistaminics and anticonvulsants.
3. IV rehydration, steroids and osmotic diuretic like mannitol.
4. Medical attendants should ideally receive pre-exposure prophylaxis with anti-rabies
vaccines and are advised to wear glasses, masks, gloves, shoes and plastic apron.
They should avoid contact with saliva, urine and tears of the patient. Patients
with rabies are potentially infectious because the virus may be
present in the saliva, vomits, tears, urine or other body fluids.

15. Prevention of human rabies
Post-exposure prophylaxis
Pre-exposure prophylaxis
Post-exposure treatment of persons who
have been vaccinated previously

16. 1. General consideration
 Anti-rabies treatment for those who were bitten by a suspected rabid
animal.
 The aim of post-exposure prophylaxis is to neutralize the inoculated virus
before it can enter the nervous system.
2. Local treatment of wound
 To remove as much virus as possible from the site of inoculation before it
can be absorbed on nerve endings.
 Animal experiments have shown that local wound treatment can reduce
the chances of developing rabies by up to 80%.
a) Cleansing: for at least 15 minutes
b) Chemical treatment: alcohol (400-700 ml/litre), tincture or 0.01 %
aqueous solution of iodine or povidone iodine.
c) Suturing: not be immediately sutured to prevent additional trauma
which may help spread the virus into deeper tissues. If suturing is
necessary, it should be done 24-48 hours later.
d) Antibiotics and anti-tetanus measure
POST-EXPOSURE PROPHYLAXIS
3. Immunization:
 Concentrated and purified cell-
culture vaccine (CCV) and
embryonated egg-based vaccine
(EEV) have proved to be safe and
effective in preventing rabies.
 These vaccines are intended for pre-
exposure as well as post-exposure
prophylaxis.
 All CCV & EEVs should comply with
the WHO recommended potency of
2.5 IU per single intramuscular dose
(0.5 ml or 1.0 ml volume after
reconstitution, depending on the
type of vaccine).

17. The guidelines for the post-exposure treatment
by the WHO are given in Table 1.

18. Intramuscular administration of vaccine for
post-exposure prophylaxis
The post-exposure vaccination schedule is based
on injecting 1 ml or 0.5 ml (the volume depends
on the type of vaccine) into the deltoid muscle (or
anterolateral thigh in children aged <2 years) of
patients with category II and III exposures.
The recommended regimen consists of either a 5-
dose or a 4-dose schedule:
1. Essen regimen: the 5-dose regimen prescribes 1
dose on each of days 0, 3, 7, 14, and 28.
2. Zareb regimen: the 4-dose abbreviated multisite
regimen prescribes 2 doses on day 0 (1 in each of
the 2 deltoid or thigh sites) followed by 1 dose on
each of days 7 and 21.

19. Post-exposure prophylaxis for previously
vaccinated individuals
• 1 dose delivered intramuscularly (IM) or delivered intradermally
(ID) on days 0 and 3 is sufficient.
• Rabies immunoglobulin is not indicated in such cases.

20. Guide for pre-exposure prophylaxis
(PrEP)
1. Recommended for anyone at increased risk of exposure to rabies virus (for
example laboratory workers dealing with rabies virus and other lyssaviruses,
veterinarians and animal handlers).
2. Travelers with extensive outdoor exposure and children living in rural high-risk
areas are at particular risk.
 PrEP schedule requires intramuscular doses of 1 ml or 0.5 ml, depending on
the vaccine type, or intradermal administration of 0.1 ml volume per site (one
site each day) given on days 0, 7 and 21 or 28.
 Booster doses of rabies vaccines are not required for individuals living in or
travelling to high-risk areas who have received a complete primary series of
pre-exposure or postexposure prophylaxis with a CCV.

21. Thankyou for your attention