1. بسم الله الرحمن الرحيم Zoonoses Disease Lecture-1 Introduction

2. Definition
Infection: pathogenic microorganisms penetrate the host defenses, enter the tissues, and multiply
Disease: The pathologic state that results when something damages or disrupts tissues and organs
Infectious disease: the disruption of a tissue or organ caused by microbes or their products
-Pathogen: a microbe whose relationship with its host is parasitic and results in infection and disease
Type and severity of infection depend on -Pathogenicity----of the organism and the condition of its host. (pathogenicity:the ability of an infectious agent to cause disease)

3. Emerging Infectious Disease
An infectious disease that has newly appeared in a population or is rapidly increasing in incidence or geographic range
On average, 1 newly identified infectious disease every year for each of the last 30 years (WHO)

4. Emerging Infectious Disease
Approximately 75% of recent emerging infectious diseases have been zoonoses
Avian Influenza Virus
Ebola Virus
Anthrax

5. DEFINITION
Zoonoses : are infections which are naturally transmitted between vertebrate animals and people.
The term zoonosis'Derived from the Greek
ZOON (animals) and NOSES (diseases)
People, animals, birds, arthropods and the inanimate environment are all involved in cycles of zoonotic infection

7. Reservoirs: Where Pathogens Persist
Reservoir: the primary habitat in the natural world from which a pathogen originates
Source: the individual or object from which an infection is actually acquired
Living Reservoirs
Carrier: an individual who inconspicuously shelters a pathogen and spreads it to others without any notice.
Asymptomatic carriers
Incubation carriers
Convalescent carriers
Chronic carrier
Passive carrier

8. Animals as Reservoirs and Sources
Vector: a live animal that transmits an infectious agent from one host to another
Majority are arthropods
Larger animals can also be vectors
Biological vector: actively participates in a pathogen’s life cycle
Mechanical vectors: transport the infectious agent without being infected

9. Figure 13.10

10. History

13. LLlecLec

15. Agent
Environment
Host
Zoonotic diseases are multifactorial and their occurrence is affected by interactions between the host, the agent and the environment

16. Classification of zoonoses disease according to the mode of transmission
Transmission of infections may be direct, indirect via arthropod vectors, or from environmental foci
Direct zoonosis : the disease is directly transmitted from animals to humans through media such as air (influenza) or through bites and saliva (rabies).
Cyclozoonosis :a zoonotic disease that requires at least two species of vertebrates as definitive and intermediate hosts. Examples: hydatid disease
Metazoonosis:zoonoses require both a vertebrate host and an invertebrate host; an example is trypanosomiasis.
Saprozoonosis
Combination (e.g. direct & metazoonosis)

17. eg. histoplasmosis, Toxocara canis, certain food- borne diseases
SAPROZOONOSIS
Diseases of vertebrate animals which can affect people, the infectious agents of which are either capable of replicating in inanimate sites, or require an inanimate environment for the development of an infectious stage of their life cycle
eg. histoplasmosis, Toxocara canis, certain food- borne diseases

18. Classification of zoonoses according the reservoir
Anthropozoonoses: Zoonoses where the main reservoir of infection is non-human ,but vertebrate animals
Most zoonoses are of this type e.g. bovine tuberculosis, rabies .
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.

19. Zoonoses Classification : Animal Species
Dogs & Cats as
Rabies
Roundworm
Ringworm
Cat Scratch Disease
Food Animals
Salmonella
E.coli
Brucellosis

20. Zoonoses: Animal Species
Birds:
Psittacosis
West Nile virus
Eastern Equine Encephalitis
Avian Influenza
Reptiles, Fish, & Amphibians
Salmonella
Mycobacterium
Wild Animals
Hantavirus
Plague
Tularemia
Lyme Disease

21. Rabieses (viral infection)
Rabies is a preventable viral disease of mammals most often transmitted through the bite of a rabid animal. The vast majority of rabies cases reported to the Centers for Disease Control and Prevention (CDC) each year occur in wild animals like raccoons, skunks, bats, and foxes.
First recognized by Ancient Greeks, most historically known zoonosis.
97% rabies in US is because of dog bites, most occurs in South near Mexican border. 4.7 million people are bit by dogs each year, 386,000 require emergency treatment. Most common in Asia and Africa.

22. CLASSICAL RABIES(Direct zoonoses)
Virulent rabies spread from Europe to Asia and other regions by infected dogs; many countries worldwide
Dogs most important domestic hosts, cats, cattle and other domestic animals commonly involved
Many wild reservoirs which differ between regions; principally canids (foxes, wolves, jackals) but also mongooses,,raccoons, bats
Some countries free by eradication e.g. UK
Direct zoonosis – bites, mucosal exposure, other routes e.g. corneal transplants
Foxes, dogs, etc

23. Hanta virus
First recognized in the Korean war in the 1950s along the Hantan river
New strain causing Hantavirus cardiopulmonary syndrome recognized in America in 1993
Rodent reservoir
rega/mvr/research.html

24. Thank you!
Questions?