Vaccination also known as immunization is a method of fighting against diseases, which is tested and tried. This method boosts and prepares the body to be able to fight pathogens which can cause a disease. Immunization has brought a lot of benefits to the animals as death and disease prevalence has been reduced. The benefits are more than the side effects that come with immunization and as we all know it is best that farmers prevent than cure. Immunization is best for making the body of animals resistant to animals. Modisar has been sending messages to vaccinate for certain diseases, so this article will explain in detail the benefits that come with vaccination.

Infection and Immunity

Infection is caused by organisms being bacteria, virus, fungus, parasite to mention a few. These organisms are present in the body all the time but there are other fighting organisms that minimizes their number hence suppressing them to cause any damage. These fighting organisms can be biological or manmade. The body of livestock has a defense mechanism called immune system. This system involves active (specific response by proteins to invading organisms) and innate (ingestion and destruction by cells where the infection is) responses.

Anything that the body of the animal does not accept it is considered as foreign and that is when the fighting comes in and immunity to protect the body. There are other organisms which when they enter the body they change to become part of the body and look like the fighting cells or other proteins. These are called Trojans and they are not easily cured, examples are viruses.

Immunity as already mentioned occurs in two ways the first being Innate responses which the organisms are present before birth. The other one is active or acquired responses and it is further divided in two forms being active and passive responses. Active responses here meaning when there are other foreign materials that enter the body of the animal the disease fighting organisms will produce antibodies which will fight specifically the foreign materials. Passive response is when the animal receives immunity that it has not produced itself; it can be through vaccination or during the time the calf will be suckling the colostrum.

Objectives of Vaccination

  • To provide immunity to the animal or group of animals (active immunity)
  • To provide immunity to the offspring of an animal via vaccination of the dam (passive immunity)
  • to provide immunity to the animal or group of animals and their offspring (active and passive immunity)

Types of vaccines

  • Live vaccines: These are usually a modified strain of the infection in which the ability to cause disease has been reduced or removed. Most of these descriptions are applied to viral or parasite vaccines. When presented to the animal, they act in the same way as an infection and so they multiply within the animal’s body. Thus they tend to produce a similar immune response to that seen in natural infection.
  • Dead vaccines: many are bacterial vaccines, although some viral vaccines also are dead. As any organisms present are killed during the manufacturing process, they are unable to multiply within the animal’s body. This means that the amount of immunity produced by the animal tends to be more dependent on the quantity of antigen present within the vaccine. Often various additives are included with these vaccines to increase the immune response and also to allow a long period of exposure to the antigen present within the vaccine.
  • Combination vaccines: these vaccines provide a wide range of disease fighting organisms. Different microorganisms may cause a disease ad it is not easy to detect if the disease is bacterial or virus caused unless taken to the lab, so this is when combination vaccines come in which will have disease fighting organisms for both virus and bacteria as an example.
  • Marker vaccines: Are vaccines which allow the identification of vaccinated animals from naturally infected animals.  This sometimes can be overcome by removing part of the genetic structure of the microorganism and making the vaccine from this (gene deleted vaccine). If immunity is due to the vaccine it can be shown that there is no antibody to the missing gene.
  • Recombinant vaccines: All living cells contain in their nucleus genetic information. These genetic instructions are carried by genes on strands of deoxyribonucleic acid (DNA) within the chromosomes. These sequences in all organisms are based on an arrangement of four different amino acids. This has led to the technology of identifying the role of individual genes and to determine their relative positions. Following this it is now possible to selectively remove, augment or rearrange them on the DNA strands, a process called recombination. In practice this allows desirable characteristics to be retained or enhanced and undesirable ones to be removed. This has the potential to deliver superior vaccines that produce enhanced immunity, have less side effects and can have additional beneficial characteristics. Live recombinant vaccines are able to still multiply in cells and usually give an excellent immune response as they can still simulate natural infection. Identification of genes within organisms that provide disease virulence can allow their alteration or removal thereby producing safer vaccines. It is also possible to remove an essential gene which means that should it enter the body it will not be able to spread.
  • Booster Vaccinations: as the word says the vaccines are used to boost the available antibodies or disease fighting organisms. Revaccination is required after a certain period of time. This will accelerate the response of the antibodies hence rapidly increasing them and from the initial dose.

Administering the vaccine

  • Vaccination should only be undertaken in healthy animals which are not compromised by poor nutritional or husbandry conditions or in other ways.
  • The animals should not be stressed either by the environment in which they are living or from being handled or from the administration of the vaccine. Stressed animals are less likely to produce a good immune response.
  • If conditions are too hot or too cold then immunity may not be as good
  • It is important to ensure that all the flock or herd is vaccinated simultaneously as otherwise those which have been missed may act as carriers of disease and incubate the infection. Such animals can remain a latent threat to the others.

Methods of applying vaccines

  • Injections: Most injected vaccines are given either subcutaneously (administered between the epidermis and dermis of the skin), intramuscularly (injecting directly into a muscle) or intravenous (injecting directly into a vein). They are the usual form ofapplication in ruminants.
  • Oral: A common route of application and it is used in particular with parasitic infections such aslungworm in cattle and poultry. Many live viral poultry vaccines are placed inthe water. Administration is through the mouth.
  • Intranasal: This is undertaken for respiratory diseases in cattle. The vaccines are live viral. Some can be used to vaccinate animals against viruses inthe face of disease. This is because of the rapid viral destruction. Administration is through the nose.
  • Eye Drop: Vaccination is administered directly into the mouth.
  • Water Application: However drinking water application iscommonly used in poultry where the target organ is the gut or, less frequently, the respiratorysystem. Vaccination is administered into drinking water.
  • Feed Application: Occasionally vaccines are used in the feed

Handling Vaccines and their Storage

Vaccines, particularly live ones, need to be treated with respect when handling, storing and using them.

  • It is important to read and follow all instructions on the product literature to ensure that the vaccines will produce their maximum activity.
  • Many live vaccines need to be kept under a specific storage environment that may involve keeping them away from light and in cool conditions. It is important to regularly check that a refrigerator is working at the required temperature.
  • Often once the vaccine is made up it will only be viable for a short period and again still needs to be kept in the conditions stated on the packaging. Only sufficient vaccine should be made up as can be used in the stated viability period. Other vaccine that is required to be made up later must still be kept under the required storage conditions to ensure its efficacy is maintained.
  • Dead vaccines usually require two doses and these should be administered at the interval indicated by the manufacturer.
  • When live or dead vaccines need boosting then this should be done at the intervals stated by the manufacturers.

Disposing vaccines

  • Read the instructions manual and dispose of according to their recommendations and those of the regulatory authorities
  • Always safely dispose of unused medicines and containers and application equipment (including needles into a sharps container) when vaccination has been completed.
  • In some cases, particularly with live vaccines, it will be necessary to kill off the microorganism by the use of agents such as disinfectants before disposal. This will prevent possible contamination.
  • If in any doubt always seek advice from your veterinary surgeon or whoever supplied the product.