common diseases that affect livestock

Question 1

what is the definition of a disease

Answer 1

a condition that affects the normal function of all or part of an organism & causes upset to normal homeostatic mechanisms in body

Question 2

what is the definition of an illness

Answer 2

feelings that come as result of disease
e.g. pain, fatigue, distress

Question 3

what is the definition of signs/symptoms

Answer 3

mental or physiological feature used as an indicator of a disease

Question 4

what are the differences between infectious and non-infectious diseases

Answer 4

both cause disturbance of animals normal homeostasis but:
infectious caused by invasion & multiplication of infectious agent
non-infectious caused by physical, chemical & genetic factors

Question 5

what are infectious diseases caused by and give examples

Answer 5

pathogens & microorganisms
e.g. bacteria, protozoa, fungi, non-living viruses, prions

Question 6

what are contagious diseases

Answer 6

• pass from animal to animal through direct contact
• infectious but not all infectious diseases are contagious

Question 7

what is an example of a contagious disease

Answer 7

rabies
limes disease

Question 8

explain an example of a bacterial disease

Answer 8

mastitis
infectious but not normally contagious
bacteria invade teat canal
white blood cells invade mammary tissue
bacteria release toxins causing inflation of udder
udder can shed if untreated

Question 9

explain an example of a viral disease

Answer 9

swine pox
vector transmission
blisters bursting can spread disease

Question 10

explain an example of a protozoan disease

Answer 10

coccidiosis
attack red blood cells & reproduce causing anaemia
vector transmission - ticks

Question 11

explain an example of a fungal disease

Answer 11

ringworm
fungi invade skin cells & cause lesions
transmitted via direct or in-direct contact

Question 12

explain an example of infectious prions

Answer 12

scrapie
transmitted between animals via prions that are present in environment & indirect contact
prions shed from birth fluids, faeces & saliva
prion enter via intestine or skin wound - causes proteins within nerve cells to fold incorrectly causing cell death

Question 13

what are examples of endoparasites

Answer 13

tapeworm
mites

Question 14

what are the 8 different forms of disease transmission

Answer 14

direct
indirect
airborne
vectors
fomites
inhalation
ingestion
environment

Question 15

explain contact disease transmission

Answer 15

via contact with infected animals, animal excretions or carrier
direct - nose to nose/animal to animal e.g. BVD
indirect - animal to animal via carrier e.g. non-sterile medical equipment, dirty boots/overalls

Question 16

explain airborne disease transmission

Answer 16

pathogens are transmitted through air (very small particles attached to dust, airborne droplet nuclei)
inhalation e.g. pneumonia, TB

Question 17

explain droplet disease transmission

Answer 17

tiny particles called droplet nuclei - suspended in air for days/hours
e.g. foot & mouth (usually notifiable diseases)

Question 18

explain ingestion disease transmission

Answer 18

via common reservoir - food or water
e.g. Johnes, Neospora

Question 19

explain vector disease transmission

Answer 19

insects, rodents
vector shows no signs of illness
e.g. lymes disease

Question 20

explain famine disease transmission

Answer 20

animal to animal by causal organism being deposited on surfaces (wooden barriers, gates, feed troughs etc)

Question 21

explain environmental disease transmission

Answer 21

housing, bedding, handling equipment, milking equipment etc. all ideal places for bacteria to live or spread
e.g. mastitis, digital dermatitis