Zoonotic disease

1. Zoonosis: An infection or infectious disease transmissible
under natural conditions from vertebrate animals to man.
e.g.,
•Rabies
•Anthrax
•Undulant fever/ brucellosis/ malta fever
•plague/ black death
•Tetanus ( locked jaw)
•Bovine tuberculosis etc.

2. Rabies
Primarily zoonotic disease of warm blooded animals
particularly carnivores e.g.,
Dogs, foxes, cats, tigers, jackals, wolves.
Characterized by :
Classical hydrophobia
Long and highly variable incubation period
A short period of illness due to encephalitis ending in
death.
Only communicable disease which is always fatal
despite intensive care.

3. Source of infection: saliva of rabid animals
Reservoir of infection: in 3 epidemiological forms
1. Sylvatic (wild life) rabies – wild life cycle perpetuated
by jackals, foxes, tigers etc; unidentified reservoir of
infection.
2. Urban areas:
From wild life to domestic dogs and maintained by
them i.e., from dogs to dogs which leads to 99% of
human cases.
3.Bat rabies:
Vampire bat – importance
Provides constant source of infection for wild
animals thus enabling virus to be present in nature.
Agent: Lyssa-virus type I
family Rhabdo viridae

4. Mode of transmission:
Animal bites
Licks over abraded/ un-abraded skin
Aerosols (respiratory)
Person to person rare but on record
Incubation period:
6-60 days but highly variable otherwise at site,
severity, no dose.

5. Epidemiology
Where: Approx. 40 countries including England,
Japan, New Zealand are reported to be free of rabies
because of strict importation of animals.
In Indo-Pak subcontinent, it is a major public health
problem due to large number of stray dogs.
WHO(population at risk):
Dog-handlers
Lab-workers
Cave-explorers (bat rabies)
Veterainarians
Hunters
Wild-life officers etc.
When : endemic

6. P.O.C: In days 3-5 before the onset, rarely
communicable from man to man.
Susceptibility/ Resitance: No natural immunity,
prophylactic anti-rabies if started will prevent the
disease.
Diagnosis:
History of exposure
Clinical signs/ symptoms
Microscopic examination
Characteristic eosinophilic inclusions(Negri –
bodies)can be found inside nerve cells particularly in
hippocampus and this is pathognomic sign in rabies.

7. Method of Control
Dog detention for 10 days, if dies – Rabid.
Pets – preventive vaccination
Destruction of stray dogs
Pets – leash application
Public – health education
If animal clinically rabid, even though the P.M
brain examination fails to reveal negri-bodies
vice versa or animal disappears after biting
un-identified, un-provoked attack, bitten by wild
animals – control of infected - person, contract
environment.

8. Prevention
Post exposure prophylaxis:
Local treatment of wound
Immunization + ARS ( N.T.V
D.E.V
H.D.C.V)
Pre-exposure prophylaxis:
Population at risk should be vaccinated
Post exposure treatment of persons previously
vaccinated.

9. Beware of friendly animal
(rabies and its treatment)
Mode of infection:
• Animal bite
• Contamination of wound by virus laden saliva
Media of transmission:
Saliva
Urine
Tears
Serum
Other body fluids

10. Routes of transmission:
Licks on damaged skin
Bites or scratches
Inhalation
Crossint through intact mucous membranes
Contamination of wounds
Incubation period: Highly variable ranging from
few days to several years (commonly 30-90 days)
depends upon the site & intensity of bite. Long
incubation period makes rabies a suitable
disease for post exposure prophylactic
immunization.

11. Concept of therapy:
Neutralization or removal of virus
before its lodging on the nerve
Enhancement of body immune system
for long lasting antibody response.
No lab tests (antibodies titre) are
required before initiation of anti-rabies
treatment.

12. Prevention & Treatment
Pre-exposure prophylaxis (PEP):
3 standard IM doses of cell-cultured vaccine on day 0, 7,
21, 28. Persons who are in close contact or at high risk
e.g., rabies research & diagnostic lab-workers, rabies
biological product workers, spelunkers,
veterinarians, animal control & wild life workers,
animal hunters.
Post exposure management:
Local wound treatment
Vigorous cleansing of wound with soap water,
detergent, ether, alcohol or aqueous sol. of Iodine.
Avoid wound suturing until and unless unevitable
Anti-tetanus injection
Analgesics & antibiotics symptomatically

13.  Active immunization: Semple type( sheep brain suspension) –
2.5ml SC for cosecutive 14 days on anterior abdominal wall,
followed by 2 boosters with 10 days interval & 3rd
booster dose on
90th
day
 Intramuscular regimes: Essen schedule (5 doses)
On day 0, 3, 7, 14 & 28 or 30 plus RIG (only once as soon as possible)
 Reduced or Alternate regime: (4 doses) 2-1-1 on day 0, 7 & 21
2 doses on day 0 plus RIG
3rd
on day 7
4th
(last) on day 21
 Previously immunized persons: Having adequate rabies
antibody titre , if exposed again, require 2 doses of ant-rabies
vaccine on days 0 & 7.

14. Recommended Standard Protective Rabies
anitbody titre
Recommended WHO rabies antibody titer is
0.5IU/ml,
25-30 days after 5th
or last injection
Rabies antibody titer has no significance before
initiation of treatment.
If the titer is below the required level, booster dosage
should be administered.
The protection afforded lasts for 6 months from the
completion of anti-rabies treatment.
For long term protection, 1st
booster after one year &
subsequent booster after 5 years.

15. Method of Administration
Intramuscular injection into deltoid region or
antero-lateral part of the thigh in small children.
Infiltrate half of the dosage of RIG in & around
the wounds locally & remaining should be
administered distant from the site of vaccine
administration.
Never inject vaccine or sera into gluteal region
because of dalayed absorption.
Use different syringes each time.

16. Dosage
 Human Rabies Immune-globulin (HRIG) 20IU /
kg body weight.
Equine Rabies Immune-globulin (ERIG) 40IU /
kg body weight.
Dilute 2-3 folds with sterile saline solution if the
calculated dosage of RIG is insufficient to
infiltrate all wounds.
Skin testing should be performed with ERIG and
if found to be positive, treatment should proceed
but precautionary measures should be at hand &
observe the patient for at least one hour after
injection. A negative skin test must never
reassure the physician that no anaphylactic
reaction will occur.

17. WHO Guidelines for Post exposure treatment
Category Type of contact with suspected or
confirmed rabid or wild animal or animal
unavailable for observation
Recommended Treatment
I •Touching or feeding of animals
•Licks on intact skin
None required if reliable
history is available
II •Nibbling of uncovered skin
•Minor scratches or abrasions without bleeding
•Licks on broken skin
•Administer vaccine
immediately
•Stop treatment if animal
remains healthy throughout
an observation period of 10
days or if animal is
euthanized & found to be
negative for rabies
III •Single or multiple transdermal bites or
scratches
•Contamination of mucous membrane with
saliva i.e., licks
•Administer rabies immune-
globulin & vaccine
immediately
•Stop treatment if animal
remains healthy throughout
an observation period of 10
days or if animal is found to

18. Exposure to hare and rodent seldom, if ever, requires
specific anti-rabies treatment.
If an apparently healthy dog or cat in or from a low
risk area is placed under observation, it may be
justified delaying the specific treatment.
This observation period applies only to dogs and cats.

19. Anthrax
This is an acute bacterial infection of animal
transmissible to man.
ANTHRAX / ANTHRACOSIS
Organism: Bacillus-Anthracis
Source: tissue, skin & hides, hair & wool of
animals dying of anthrax.
Reservoir: farm animals / infected cattle, sheep,
goats & horses.
Occurrence: wide spread in agricultural areas

20. Mode of Transmission
According to Clinical form
1-Cutaneous anthrax or malignant pustule –
contact of spores over skin of population at risk.
Sequence of events:
Small red indurate area
Later becomes edematous and soft
Lastly become hard, edematous & necrotic
Also characterized by lymphadenopathy,
cellulitis & septicemia.

21. 2- Inhalational anthrax or Wool sorter’s disease
(W.S.D) or pulmonary anthrax
Occurs due to inhalation of infected material
3- Intestinal or ingestion material:
Ingestion of infected meat / other material.
Incubation period 1-7 days

22. Epidemiology
When : endemic
Where : agricultural / industrial area
Who : agriculturist, hide-workers, butchers,
shepherds, wool factory workers, tanners in
tannery factory, veterinarians, farm workers /
farmers etc.
Diagnosis:
• Shears from skin lesions (cutaneous anthrax)
• Sputum examination – W.S.D
• Blood by culture

23. Preventive/Control Measures
1-Animals: Sick must be isolated and treated.
Carcases 6feet buried or burnt.
Precaution: Never opened or bled
Vaccination with alum precipitated antigen of
animals.
2-Factors:
Control of effluents
Trade-waste
Dust control / ventilation

24. 3- At Community level:
Health education
Medical care of skin
4- Material :
Disinfection:
Hair – steaming
Wool – formaldehyde
Hides – bin chloride of formic acid /HCl
In epidemic – quarantine for 10 days.