Partnership for Environmental Education and Rural Health

Texas A&M University

http://peer.tamu.edu

Vaccines control diseases and can

protect people and animals from illness

and death.

Infections What vaccines are How vaccines work History of vaccination research Future developments expected Dog and cat vaccination

Microbes invade the body

Improve general health - proper nutrition, exercise,

healthy lifestyle, etc.

Vaccinate

Eating healthy food, taking vitamins, and regular exercise stimulates the immune system.

Good sanitation practices also limits an infectious agent’s ability to spread to you and others.

Check our Web site on Body Defenses

Vaccinations help both you and your best friend stay

safe.

Target specific diseases

Protect those who are

vaccinated

Stop epidemics

Vaccinate the largest possible number of individuals in the population at risk.

Vaccinate each individual no more frequently than necessary.

Vaccinate only against infectious agents to which individuals have a realistic risk of exposure and subsequent development of disease.

Vaccines consist of killed or weakened microbes that stimulate the immune system against that microbe. Why must the microbes be

killed or weakened?

Some infectious agents can change their genetic makeup making it difficult to produce a vaccine.

Polio, Haemophilus Influenza B, Diphtheria, Tetanus, Pertussis,

Hepatitis A, Chickenpox, Measles, Mumps, Rubella, and Hepatitis B.

Have you had yours?

Microbes grown on suitable medium

Purified to remove compounds that could cause allergic reactions

(not always possible)

1. What are two main ways to improve resistance to infection?

2. Why is vaccination important?3. What should the goals of vaccination be?4. What is a vaccine?5. How are vaccines made?

Your Body’s Defense System

See separate lesson in this series on Immunity

Active Exposure to an

infectious agent triggers production of antibodies and may cause the disease.

Vaccines trigger the immune response without causing the disease (usually!)

Passive Person is injected with

antibodies (immunoglobulins).

Immediate protection, but can’t last long because it does not stimulate the immune system to make it’s own antibodies.

Passive immunization will never cause the disease.

Weakened Vaccines

• Produced by weakening a live virus or removing it’s disease-causing ability.

Pros Cons

- They elicit an immune system response and the formation of antibodies so you only have to receive the vaccine once or twice.

- They have to be stored under special conditions, like refrigeration.

- They can mutate and might cause the disease (very rare).

These vaccines are produced by killing the infectious agent.

Pros Cons

- They do not have to be refrigerated.

- They will never come back to life and cause the disease.

- They usually require booster shots because they only weakly stimulate the immune system to make antibodies.

Inactivated Vaccines

Toxoids• Made by inactivating the toxin that

some infectious agents create.• Used against Tetanus and Diphtheria.

Pros Cons

- You only have to have the vaccine once or twice.

- They will never be reactivated and cause the disease.

- They have to be refrigerated.

Subunit Vaccines• Made by taking apart an infectious agent

and only using the antigenic part (the part that stimulates an immune response).

• Example vaccines: Hepatitis B and Streptococcus pneumoniae

Pros Cons

- They cannot cause the disease.

- They are more difficult to make and require new, expensive technology.

1. How do vaccines work?2. What are antibodies and what do they do?3. What is the difference between active and

passive vaccination? What are the advantages and disadvantages of each?

4. Research is often aimed at developing sub-unit vaccines. Why?

1798 – smallpox

1885 – rabies

1897 – plague

1923 – diphtheria

1926 – pertussis

1927 – TB

1927 – tetanus

1935 - yellow fever

1945 - influenza

1955 - polio (inj.)

1962 - polio (oral)

1964 - measles

1967 – mumps

1969 – rubella

1970 – anthrax

1977 – pneumonia

1981 – hepatitis B

In the late 1700s, a very deadly virus called smallpox was spreading through England.

Milk maids did not get smallpox (yet were continuously exposed to cowpox).

In 1796, Edward Jenner inoculated a boy with cowpox, then showed later that smallpox inoculation did not infect him.

Creation of an anthrax vaccine by growing the microbe in a culture medium until it lost ability to cause sickness. Today’s vaccine: 99% effective against cutaneous

anthrax See PEER professor presentation

on anthrax

Creation of a rabies vaccine by growing the microbe in duck eggs until it lost ability to cause sickness.

1. What was Edward Jenner’s contribution to vaccination research?

2. What were Louis Pasteur’s first contributions to vaccination?

3. What was the average human life span before the advent of vaccination? What is it today?

Genetically engineer foods to contain parts of disease-causing organisms.

Such a vaccine could be “grown” around the world, even in underdeveloped countries.

Eliminates the need for expensive storage, transportation, refrigeration

Many viruses can change their genetic makeup to become stronger and resist vaccines or antibiotics that were once effective.

Gene sequencing of these microbes helps scientists to: Understand how microbes

invade and attack. Identify antigenic sites as

targets for drugs or sub-unit vaccines.

Hoping to prevent another 1918 flu epidemic disaster.

Identify an antigen

Identify gene that makes antigen

Insert gene into a harmless virus

Infect patientwith the virus

Gene makes the antigen inside

the patient Antigen induces

antibody productionby the patient

One strategy for genetically engineered vaccines

These rare reactions range from allergy symptoms to sudden death. Pets should be monitored for vaccine reactions soon after vaccinations.

Anaphylaxis is a rare, life-threatening, immediate allergic reaction. Readily treated by a veterinarian, but if untreated, it may result in shock, respiratory and heart failure, or even death.

Pain, swelling, redness, and irritation can occur at the injection site. Mild fever, decreased appetite, and depression may also occur. If you notice any of these signs in your pets, contact your veterinarian immediately.

These reactions may sound scary, but the risks of not vaccinating dogs and cats are far greater.

Cindy ChangClass of 2009

College of Veterinary MedicineTexas A&M University

Rabies – for all pets! (Killed Virus) Dogs

Parvovirus – Modified Live Virus Distemper – Modified Live Virus

Cats Feline Leukemia Virus – Killed Virus Panleukopenia - Modified Live Virus

Horses Tetanus - Toxoid - Encephalomyelitis -

Killed West Nile Virus – Killed - Flu/Rhino - Killed Strangles – Inactivated

1. Young animals need vaccinating early and often because their immune system is not yet developed.

2. Later, booster shots may be needed because protection “wears off.”

Pets need to be healthy to receive vaccination. Sick animals do not respond well to vaccination.

Veterinarians provide health and nutrition information that you can’t get from pet supply stores.

Pets that visit the veterinarian once a year are healthier, happier, and live

longer.

Rabies vaccine is required by law in many states. Why?

Puppies should receive a single dose of killed rabies vaccine at 16 weeks of age.

Adult dogs with unknown vaccination history should also receive a single dose of rabies vaccine.

A booster is required one year later for both puppies and adult dogs. Rabies vaccination should be performed every 3 years.

See separate lesson on rabies in this series.