veterinary epidemiology which is given to animal science

introduction to epidemiology

1. Animal Health and Disease Control By Megarsa Gemechu Department of Animal Science, Faculty of Agriculture Wallaga University 11-Aug-24 By: MG 1

2. Chapter 1 General Concepts of Animal Health 11-Aug-24 By: MG 2

3. Chapter contents: Concept of disease and its importance Signs of health and diseased animals Classification and cause of disease Methods of disease transmission Factors associated with the spread of infection Prevention and control strategies of infectious disease 11-Aug-24 By: MG 3

4. 1.1. Concept of disease and its importance Animals that are healthy will perform well and produce maximally for the benefit of man. Diseases generally reduce the performance or productivity of animals especially food animals ( livestock) and ruminants in particular. It is therefore important that good animal management practices be observed on a farm or where animals are kept not just to keep diseases away but for maximum performance and for the well being of animals. 11-Aug-24 By: MG 4

5. 1.1. Concept of disease and its importance Health is a state of complete physical, mental, and social well-being and not merely the  absence of disease or infirmity. Animal health  has been defined as a “state of physical and psychological well-being and of productivity, including reproduction ,”. Disease is thus a non balanced perturbation of one or more body function(s), including responses to infectious and noninfectious agents  Disease : impairment of normal functioning, manifested by signs and symptoms, it can be defined as a medically definable physiological dysfunction . 11-Aug-24 By: MG 5

6. Cont. The clinical sign (changes observed when an animal is sick is a basis for diagnosis or determining what is causing the sickness in the animal), and diagnosis can be defined as the art and science of determining the nature and causes of diseases and differentiating between diseases. 11-Aug-24 By: MG 6

7. Cont. To arrive at a diagnosis, you have to get some information or facts about the animal. The information you gather or collect should be as comprehensive as possible and these can be regarded as components of diagnosis. These include: History taking :- This is gathering some information about the animal such as identity of the animal ( species, name or tag no., age, sex, breed, colour of the animal etc ), when the animal was first noticed to have changed in behavior or performance, how long this condition has been on etc. 11-Aug-24 By: MG 7

8. Cont. Physical examination :- This done by observing the animal itself for any sign of abnormality , taking the temperature, pulse rate, respiratory rate. If this done on a farm, it can include looking at the housing and environment where the animal is kept, the type of feed given to the animal or animals etc . Laboratory examination :- This is carried out on samples or materials collected from the animal or the environment where the animal is kept. The sample collected is subjected to several laboratory procedures to detect the presence or absence some disease-causing agents or substances. 11-Aug-24 By: MG 8

9. Cont. The importance of animal health Firstly , it safeguards the health and welfare of the animals (treatment cost).   It also safeguards the safety of food to consumers of fresh or processed food of animal origin. As healthy animals are able to produce more offspring, which leads to increased economic activity. It ensures quality assurance for trade in animals and animal products. And it safeguards human health (zoonotic importance). Animal health surveillance is part of the wider objective of one health surveillance. 11-Aug-24 By: MG 9

10. 1.2. Signs of health and diseases Healthy Animal:- Has a good appetite Appears bright, alert and responsive Stay with the flock Has smooth, clean and shiny coat Has clear eyes Has an erect tail and a moist nose no wounds on/in their body 11-Aug-24 By: MG 10

11. Healthy Animal… 11-Aug-24 By: MG 11

12. Cont. Sick/unhealthy animal Has reduced appetite Has fast or slow breathing lay down separated from the flock/herd Has ill appearance with a dull matted coat, hunched up stance, tail and ears down Has dry nose or discharge from the nose, eyes, mouth irritable, listless, lame, fever 11-Aug-24 By: MG 12

13. Pictures of diseases that cause diarrhea 11-Aug-24 By: MG 13

14. Pictures of diseased animal Lameness fascioliasis 11-Aug-24 By: MG 14 Dehydration problem

15. Respiratory problem/Nasal discharge 11-Aug-24 By: MG 15 Skin disease

16. Milk fever Mastitis 11-Aug-24 By: MG 16

17. 1.3 . Classification and cause of disease Based on the nature of its cause disease could be broadly classified as: Infectious diseases : are associated with living agents, such as parasites, bacteria , virus, fungus Non infectious : Mechanical injuries, nutritional deficiencies, poisoning, genetic disorder … 11-Aug-24 By: MG 17

18. 1.4. Methods of disease transmission Transmission may be either horizontal (lateral) or vertical Horizontally transmitted infections are those transmitted from any segment of a population to another. Vertically transmitted infections are transmitted from one generation to the next by infection of the embryo or fetus while in utero (in mammals) or in ovo ( in birds ) by trans-ovarian route or transmission on the egg shell Transmission by milk to offspring is also considered , by some, to be vertical 11-Aug-24 By: MG 18

19. 1.5. Factors associated with the spread of infection Environmental factors Water, Sanitation, food and air quality Climate Host Age, sex, species and breed Immunity Genetic Agent Virulence and pathogenicity Host and agent interaction 11-Aug-24 By: MG 19

20. 1.6. Prevention and control strategies of infectious disease There are three levels of prevention : 1. Primary prevention: Prevent occurrence of new disease Eliminate causes of disease or increasing resistance to disease. – Health promotion (e.g. housing ) – Prevention of exposure (e.g. vector control) – Prevention of disease ( e.g. vaccine ) 11-Aug-24 By: MG 20

21. Cont. 2 . Secondary prevention: Diagnose and treat the disease stop or slow the progression of disease E.g . Early detection and treatment 3 . Tertiary prevention: Treat chronic disease to reduce their severity, prolong the life span (e.g. bovine TB) prevent further disability or death 11-Aug-24 By: MG 21