بسم الله الرحمن الرحيم Zoonoses Disease Lecture-1 Introduction

1. بسم الله الرحمن الرحيمZoonoses DiseaseLecture-1Introduction

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 • 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

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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. 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)

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

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 www.kuleuven.be/ rega/mvr/research.html

24. Thank you! Questions?