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VETS1018 Professor Toan Cheat Sheet (DRAFT) by

Easy learning for professor Toan VETS1018

This is a draft cheat sheet. It is a work in progress and is not finished yet.


of human infectious diseases are ZOONOTIC
of it is of ANIMAL ORIGIN
In 5 human diseases
3 have an animal origin
80% of Bioter­rorist agents
Zoonotic Pathogens

Chain of Infection

Chain of Infection:
Starts with Suscep­tible Host

Field expertise and Knowledge Exchange

Experi­mental Knowledge
(knowing what works and vice versa)
Profes­sional Knowledge
(professional conduct standards)
Land Manager
Scientific Knowledge
(Knowing latest techno­logies, techni­que­s,..)
Experi­ential Knowledge (based on experiment interv­ent­ions)
Regulatory Knowledge (Knowing legisl­ations, laws, polici­es,...)

Pig diseases

-PRRSv (Porcine Reprod­uctive and Respir­atory Syndrome virus)
-PCV associated diseases
-Foot and mouth disease
-ASF(African Swine Fever)
-Classical swine fever
-Swine Influenza
-Nipal virus infection
-Menangle virus infection
-Reston Ebolavirus infection

Role of Veteri­narian

As frontline of:
-Detection of animal diseases
-Prevention of animal diseases
-Treatment of animal dieases
Many are zoonotic

Normal role of veteri­narian:
-Work to keep the animal healthy and treat diseases
-Conduct research to:
(1)Develop improved:
(2)Serving as public health profes­sionals

Role of Veteri­narian (Cont.)

Clients and the public expect Veteri­narians to:
-No matter what their responsibilities
-Must be knowle­dgeable about emerging and exotic diseases
Animal health, human health, food production, and the enviro­nment are inextr­icably linked.
• The multid­isc­ipl­inary training that veteri­narians receive provides the tools needed to play an important role in meeting the challe­nges.

Role of Veteri­narian (Cont.) (2)

Veteri­narians can contribute by:
- Mainta­ining and improving the health and welfare of food producing animals in the developed and developing world
- Providing health care to prevent and control zoonotic diseases in companion animals
- Contro­lling food borne and zoonotic diseases in food producing animals
- Conducting research for improved vaccines, pharma­ceu­ticals, and diagno­stics
- Working to ensure the health of wildlife and mainta­ining biodiv­ersity
- Working to reduce the impact of livestock, poultry, and aquatic animal production on the enviro­nment
- Improving the health of aquatic animals, exotic animals and zoo animals. - Educating students, animal owners, and the public regarding these critically important issues.

Definition of health

State of physical and psycho­logical well-b­eings that enables animals to express its genetic potential for maximising:
-Produc­tivity perfor­mance
-Reprod­uctive performance
-Lean meat production

Definition of Disease

Having a disorder of a body structure or function, one that produce clinical signs of a specific location, instead of just being a direct result of a physical injury.
Disease is associated with:
- An unhealthy state of body and mind
- Accomp­anied with pain and uneasiness
--->Unable to exert full genetic potential --> Decreased produc­tivity

Disease (Cont.)

Clinical Disease Level is described by the term: MORBIDITY
Disease can have:
- Clinical (Showing external clinical signs)
- Subcli­nical (Not showing any obvious signs)
-->Subcli­nical Disease can lead to lowered produc­tivity if goes unnoticed.

Clinical vs Subcli­nical

Diseases in the stage with observable abnorm­alities in a body structure or function of the patient, seen by the client or veteri­narian.
- Are custom­arily graded:
+ Based on severity: Severe, Mild, Moderate, etc...
+ Based on speed of onset and disease progress: Peracute, Acute, Subacute, Chronic, etc...
Diseases in the stage that have no observable abnorm­alities in the body structure or function
Every healthy herd at least carries a multitude of potent­ially infectious pathogens in: Guts, Respir­atory, Skin, Genitals. However, it isn't pathogenic enough to cause clinical or subcli­nical diseases.

Health vs Diseas­e-free

Pathogens and Immune system

There is a delicate balance between the potential infectious pathogens and the respon­siv­eness of the immune system.
Pathogens > Immune System: Immune is impaired --> Pathogens can causes diseases
Pathogens = Immune System: Pathogens can reproduce, causing a local infection but are killed off quickly
Pathogens < Immune: The system over-r­eacted to a specific pathogen, having inappr­opr­iated immune responses --> Hypers­ens­itivity
Physical or Psycho­logical distur­bance (disorder) can affect the equili­brium of these two --> Maintain good physical and mental health as to not impair the system.

Good animal husbandry and stockm­anship

Good animal husbandry
A branch of agricu­lture concerned with many aspects of food production animals.
--> Good animal husbandry is good housing, good nutrition and good manage­ment.
Good stockm­anship
A branch of science concerning the handling of animal's welfare and well-being
--> Good stockm­anship is good handling of the animal in a safe, efficient, low-stress manner, priori­tizing their health and welfare.

Pathogens and Immune system (Cont.)

The balance is more precarious when upscaling from an individual to a herd.
Poor husbandry would cause infection in a small groups, the pathogenic organisms gradually build up in the herd to a certain concen­tration that can infect even resilient ones.
The concen­tration continues to build up and destroy the balance, threaa­tening to overwhelm the collective herd immunity.

Host/A­gen­t/e­nvi­ronment Triangle

exposure to specific pathogens
and their characteristics
Age, breeds, sex, welfare,..
Husbandry methods,
climate, hosuin­g,...

Animal behaviors

- Interact with one another
- Curious
- BAR (Bright, Alert, Responsive)
- Show interest when disturbed
- Observe respiratory rate
- Lethargic (move slowly)
- Depressed { Head drops low, ears droop)
- Isolate from herd, bumped by pen mates
- Inactive
- Not interested in eating/drinking
- Decreased BAR manner


- Readily observed under microscope ( especially when stained)
- Recognized by their family group using:
+ Shape
+ Size
+ Antigenic charac­ter­istics
+ Biohemical charac­ter­istics
+ Identi­fic­ation of DNA


- Smallest of the infectious agents
- Can only be seen using electron microscope
- Use vaccines to artifi­cally acquire active immunity

Why viruses mutate more than bacteria?

Virus mutates as part of natural replic­ation. During replic­ation, it may undergo "­copying errors­" (genetic mutati­ons), which keeps gradually happening, eventually lead to altera­tions of the virus' surface proteins or antigens.


Eukaryotic organisms, including molds and yeasts, also mushroom.
- Found in damp condit­ions: badly stored cereals, moist places,...
- Produce Mycotoxins during Multip­lic­ation in some species --> Causes clinical signs if eaten.

Fungi (cont.)

Methods to not grow fungi:
- Do not store moist corn or cereals
- Check holding bins (for feeds) for leakages and bridged feed monthly
- Do not let grain ferment
- Do not let feed to waste ad fermen­tation happening in feed troughs
- Check feed hoppers daily
- Always examine basic feed ingred­ients
- Empty grain bins regularly.
- Visually check the final feed prior to feeding

Fungi (cont.)

Example Diseases:
Certain species of fungi called Dermat­ophytes can cause skin infection on and develo­pment of ringworms.
--> Dermap­hytosis

Question: How to detect fermen­tation is happening?

- pH test: 4.6 or below


-Live inside body: Endopa­rasites
- Live externally on or in the skin: Ectopa­rasites
- Smallest parasites: Coccidia: --> Coccid­iosis (Bệnh Cầu Trùng): They live in intestine (the lining of smaall intestine)
- Have a life cycle: from eggs to larvae to adults
- Some parasites require interm­ediate host, such as lungworms use earthworm as interm­ediate.

Why should we know about a virus life cycle?

A virus life cycle is the duration of living of the parasite
When clinical signs appear, that means the parasites must haave been in the host for most of its life cycle. (Already an adult parasite).
Example: A parasite with a 1-week life cycle --> Infect an individual host --> Host shows signs at week 3 --> Use parasi­ticides on week 2 of other cows
Know the specific stages of life cycle to effect­ively prevent the parasite
The most effective and easy ways to break the cycle is to:
- Have good hygiene
- Remove interm­ediate host if present


One of the major causes for diseases to develop inside body.
- Trauma­tized indivi­duals are previously affected by extrinsic factors such as:
- Housing managements
- Other animals of same species
- Fighting
- Poor management techniques
Most are preven­table with good management

Hereditary and Congenital

Hereditary and Congenital diseases are common in swines and cover a whole range of conditions.
What is the different between Hereditary and Congential?
Meaning the condition was inherited from the parents to the offspr­ings.
Meaning the condition is present at birth but implying there was an abnorm­ality happened during fetus develo­pment instead of being inherited.

Enviro­nmental problems

Enviro­nmental problems:
- Littering
- Contam­inating surrou­ndings with bacter­ia/­che­mical residu­es/...
- Releasing greenhouse gases
--> Contribute to some disease develo­pments.
Do PLF (Precision Lifestock Farming):
- Effect­ively reduces:
+Ammonia, Greenhouse gases, Nitrates, Phosph­orous, heavy metals, antibiotics.
- Effect­ively increases:
+ Good health
+ Good well-beings
+ Good productivity
+ Good reprod­uctive perfor­mance.


- Happens when some cells don't die and continue to grow abnorm­ally.
Pressure of the abnormal growth put on other body parts --> cannot function normally when being pushed --> Illness occurs
-Affected body parts also cant function properly --> Failure --> Illnessz
- Can also cause fever and other conditions

Nutrit­ional Deficiency and Excesses

- Knowledge on Nutrit­ional requir­ements and Components of dietary ingred­ients helps reduce problems relating to faulty nutrition.
- Four aspects in diet that deficiency affect: vitamin, protein, minerals, energy
Vitamin defici­encies can cause poor growth;
Mineral defici­encies are not uncommon due to demands for increased lactation
**Nutr­ional excesses can also causes illness.

Metabolic Diseases

An upset (dysfu­nction) in the body functi­onings, usually caused by intensive animal production
Ex: Hyperc­alcemia


- A part of Hypers­ens­itivity
- Caused by an allergen
- Makes immune system attacks parts of the body


- Common in animals
- Caused by a variety of agents (including rotten feed)
- Many substances (such as drugs) can have lethal dose, meaning reaching a toxic-­ind­ucing level and cause illnesses.
- Poisoning can affect indivi­dually or together with others.


Stress would cause:
Caused by intera­ction with adverse manage­ments and enviro­nments.
- Impairment to digestive system
Good management will increase well-b­eings and biological efficiency of the animals.
- Increased secretion of stress hormones: cortic­ost­eroid suppresses immune system
- Increased body temp. and heart rate
--> Increased risk of diseases


3 principle reasons for transm­ission of diseases:
2 Types of transm­ission:
- Poor sanitation
Horizontal: From 1 animal to another
- Improper management
Vertical: From parents to offsprings
- Introd­uction of a foreign animal to the herd

Eight good management practices

- Isolate soon-to-be added animals for 3 to 4 wks before adding to the herd. (Both new animals, cull animals and those exposed to other animals)
- Install good immuni­zation program
- Clean, healthy enviro­nments are provided
- Adequately nutritious rations
- Visitors and new animals not allowed in livestock areas
- Quickly and accurately diagnose diseases
- Consult a veteri­narian when problems arise
- Handled livestocks properly