Infections spread from animals to human are called zoonotic infections. The term zoonos is’ Derived from the Greek ZOON (animals) and NOSES (diseases) Pathogens shared with wild or domestic animals cause more than 60% of infectious diseases in man.

1. Zoonotic Infection
Amjad Khan Afridi
Lecturer,
Department of Health & Biological Sciences
Abasyn University Peshawar

2. Introduction
• Infections spread from animals to human are called
zoonotic infections.
• The term zoonos is’ Derived from the Greek
• ZOON (animals) and NOSES (diseases)
• Pathogens shared with wild or domestic animals cause
more than 60% of infectious diseases in man.

3. 3
Anthropozoonoses: Zoonoses where the main reservoir
of infection is non-human vertebrate animals
Most zoonoses are of this type e.g. bovine
tuberculosis, rabies, leptospirosis
Zooanthroponoses: Diseases that mainly affect people,
which may be transmitted to animals, which then act as
temporary reservoirs of infection
Examples are Mycobacterium tuberculosis in dogs,
infectious hepatitis in apes
ZOONOSES DEFINITIONS

4. Cont..
• They can either be bacteria, viruses, fungi or parasites.
• Zoonotic infection are common in man because he
interacts with animals in his daily life .
• The animals include pets that offer companionship, and
animals that are important food sources such as meat,
dairy and eggs and the wildlife.
• This happens because some of this microorganism can
infect a varied number of hosts.

5. Such pathogens can either be;
1. Bacterial
2. Viruses
3. Parasite
4. Fungi
5. Prions

6.  Man get infected with zoonotic infection through
1. Direct contact with an infected animal
2. Indirect contact with the animal
3. Through vectors
4. Through food that was contaminated with the infected animal.

7. 1. BACTERIA
1. Anthrax
•Bacillus anthracis is Gram-positive sporing rod shape bacteria.
•Present anywhere, specially in the soil, infected animals and human.
•Spread of the bacillus to human happens due to butchering or eating
wildlife or infected domestic carcasses.
•Bush meat trade
•Common in west and Central Africa where demand for bush meat is
for time greater than in the Amazon basin.
Eschar

8. ANTHRAX
Organisms enter via:
 Skin (cutaneous anthrax)
 Lungs (pulmonary anthrax, woolsorter’s disease)
 Gastrointestinal tract
Clinical signs include:
• Shortness of breath.
• Confusion or dizziness.
• Cough.
• Nausea, vomiting, or stomach pains.
• Headache.
• Fever
• Chest Discomfort.

9. 2. Bovine tuberculosis
• Bovine tuberculosis is a chronic bacterial disease of animals and
humans caused by Mycobacterium bovis.
• Slow-growing (16–20h generation time), aerobic bacterium, Gram
positive, acid-fast, slender, non spore-forming, rod-shaped, and
free-living in soil and water
• In a large number of countries bovine tuberculosis is a major
infectious disease among cattle, other domesticated animals, and
certain wildlife populations.
• Aerosol exposure to M. bovis is considered to be the most frequent
route of infection of cattle, but infection by ingestion of
contaminated material also occurs to human.

10. 3. Escherichia coli
• Animals are recognized as a reservoir for human intestinal
pathogenic E. coli O:157.
• Commensal E. coli strains potentially carrying virulence factors
involved in the development of human pathologies also colonize
the intestinal tract of animals
• Through contact with animals especially poultry and companion
animal may contaminates ones hand food or formite

11. 4. Salmonella
 Salmonella typhi and Salmonella paratyphi cause enteric fever
(typhoid and paratyphoid fever) characterized by;
 High fever, abdominal pains, headache, vomiting, and diarrhea
followed by constipation and rashes lasting for several weeks or
months.
 Birds are the main reservoir of Salmonella enteritidis and human
beings are most commonly infected after eating contaminated eggs
or egg products from domestic hens.

12. 5. Brucellae
• Brucellae are Gram-negative coccobacilli (short rods).
• They are non-sporing and lack capsules or flagella and,
therefore, are non-motile.
• Brucella melitensis and Brucella abortus cause brucellosis or
undulant fever, or goat-milk fever.
• Brucellosis is contracted by ingestion of contaminated,
unpasteurized milk or milk products or through contact with
infected animals by means of skin abrasions.
• Brucellosis, especially caused by B. melitensis, remains one of
the most common zoonotic diseases worldwide with more than
500,000 human cases reported annually.
• Although many countries have eradicated B. abortus from cattle,
in some areas B. melitensis has emerged as a cause of infection in
this species as well as in sheep and goats.

13. 6. VIRUSES

14. • Rabies, also known as hydrophobia, is a highly fatal
viral disease that causes inflammation of the brain in
humans and other mammals.
• It is caused by Lyssavirus type 1.
• Rabies is mostly found in wild animals like bats,
raccoons, skunks, and foxes as well as dogs.
• Transmission of Rabies to human;
• Bites (95%),
• Scratches &
• Licks from infected animals.
7. Rabies virus

15. The arthropod-borne viruses, or arboviruses,Viruses of vertebrates.
Transmitted by blood-sucking arthropods/ insects vectors from one vertebrate host to
another.
Can cause infection on animals & birds.
Transmitted to human by bite of infected mosquitoes, ticks & sand flies.
• West Nile virus, Dengue, and chikungunya, rift valley fever
• Transmitted from mammalian reservoir to man through mosquitoes
especially Aedes
8. Arthropod-Borne (Arboviruses ) Viral Diseases

16. 9. Fungi
• Dermatophytoses also called ringworm or tinea, are superficial
mycoses that may be acquired from infected animals and affect the
skin, hair and nails of humans, causing itching, redness, and hair
loss.
• Another mycotic infection that can be zoonotic is
sporotrichosis.
• Sporotrichosis (also known as “rose gardener's disease”)
is an infection caused by a fungus called Sporothrix.
• This fungus lives throughout the world in soil and on
plant matter such as sphagnum moss, rose bushes, & hay.

17. Hookworms & Roundworms
 Carried by dogs and cats
 Kids often get infected from playing in sand boxes
which animals have defecated
 Or by putting toys in their mouth which have been on
the ground

18. 10. Roundworms
 Roundworms & whipworm are small parasitic that can live in intestine,
which is part of digestive system.
 These caused ascariasis infection of intestines which is mostly common in
children and as compare to adults.
 They’re known as Soil-Transmitted Helminths (STH) because the
infection spreads through contaminated soil.
 It’s common throughout the world in places where sanitation is poor.
 Roundworms can live in the human intestine for a long time. They can be
harmful and cause many problems, including abdominal pain, fever
and diarrhea.
 The worm looks like the common earthworm. It’s about 6 to 13 inches
long and about as thick as a pencil. Up to 100 worms could potentially
infect a person.

19. 11. Hookworms
 Parasite infection caused by Necator americanus & Ancylostoma
duodenale.
 These are known as soil-transmitted helminths (parasitic worms).
 Its estimated that 576-740 million people in the world are infected.
 In 20th century, Hookworm was once widespread in the United States,
particularly in the southeastern region.
 High-intensity hookworm infections occur among both school-age
children and adults.
 Cause anemia and protein deficiency.
 Hookworms live in the small intestine & eggs are passed in the feces of an
infected person.

20. 11. Hookworms
 Larvae can penetrate the
skin and gain entry into the
human body.
 Bare feet are a common
route of entry
Wearing shoes is one of the best ways to
prevent parasites from entering your feet!!!

21. 12. Trypanosomiasis
• Causes sleeping sickness
• Transmitted by tsetse fly (Glossina species), female and male
from mammals and birds to man
• Trypanosomiasis, also known as “sleeping sickness”,
is caused by microscopic parasites of the
species Trypanosoma brucei.
• It is transmitted by the tsetse fly (Glossina species), from
mammals and birds to man
• This mostly found only in sub-Saharan Africa.

25. 14th March, 2023