Immunity is everything to humans and animal alike. Immunity is what keeps us healthy. A good working animal immune system comes from proper vaccination, proper deworming, healthy eating, exercise, and avoiding as many environmental toxins as possible. Genes also play a part. Nowhere is this most readily seen than in the dog.
As we bred for a character or trait we liked, humans inadvertently bred certain dogs to be more susceptible to certain diseases. Hip dysplasia is common in German Shepherds. The Lhasa apso breed suffers from dry eye, while lupus erythematosus is often found in Collies.
While we can't control genetics as pet parents, we can help ensure that our pets have the strongest immune system possible. Understanding how the immune system works and knowing what specific challenges may lay ahead for your pet, may help you prevent disease, or at least catch problems early.
One can be easy overwhelmed by the functioning of the immune system, but it is important in understanding how vaccines work as well as understanding lab work. Most people don't care to know, as long as it works, but when you realize everyone, including your pets, have their own personal military inside, it's really cool!
The immune system works like this: Just as the military is broken down into branches like the marines/navy, army, and air force, the body's military is broken down into physical immunity, innate immunity, and adaptive immunity.
Physical immunity is like the marines, the first line of defense. The immune system is made up of the skin, the membrane lining the organs, and even secretions like tears and digestive tract juices. The bad guys are the antigens of germs, viruses, and bacteria. They show up and the physical immunity marines (PIM's) kick into gear. If for some reason, antigens break through the PIM's, innate immunity, also known as nonspecific immunity, takes over. This is the 1st Calvary division of the army. The 1st Calvary is made up of platoons of white blood cells which I will explain more about in a moment.
Part of the security force is adaptive immunity or specific immunity. These are the intelligence officers that help identify the bad guys. While innate immunity has been in the field fighting every enemy, adaptive immunity identifies specific targets. How do they acquire this information? Being exposed to it in the past through past battles or in small skirmishes caused by guess what? Vaccines. The vaccines, in causing a small fight, help the force know exactly what the evil antigens look like, so when they see them in the future, they recognize them sooner. The antigens are marked for death and adaptive immunity is the memory of what those guys look like.
The blood vessels are used as the transportation system for this military response. While the red blood cells (RBC's) are providing oxygen to keep the troops alive, the platelets, which are made by the bone marrow, jump in like medics and create blood clots where any damage is done. It is thanks to the platelets that we don't bleed out.
Meanwhile, the white blood cells (code name leukocytes) are carefully split into platoons with specific jobs. Phagocytes are the special forces that dive into the bloodstream to carry them into the heat of battle. The lymphocytes begin producing the weapons, called antibodies against the antigens, be they infection, virus, cancer cells, etc. These guys are further divided into T cells, that pick up the weapons and begin fighting, and B cells that dive on top of the enemy so that the special forces guys can easily recognize them.
When the phagocytes get to the battleground, they divide into small groups. First are the monocytes that morph into macrophages that consume large foreign particles and the cellular debris left behind. Second are the granulocytes that split up into three groups:
The eosinophils and basophils concentrate on any allergic reactions, be it food allergy, bee stings, etc. The neutrophils jump into battle anywhere they detect bacteria and fungi. If there is inflammation, you can bet the neutrophils are there.
The carefully organized immune military is what keeps us, and our pets, alive and healthy. Our immunity is an amazing feature of our shared anatomy that is beautiful when it works. When lab work is taken on a sick animal (or human), the presence of these guys gives us a clue as to what is going on in the body. If white blood cells are abundant, you know a battle of some kind is going on. If there are a high number of eosinophils and basophils, you are more than likely looking at some type of allergic reaction. If neutrophils are present in high numbers, you are looking at some type of infection.
Hopefully, by breaking down the topic of immunity into simple concepts, we can understand the need to ensure that our pets have the strongest immunity possible. It's one way of, not only keeping our pets healthy, but saving money by preventing disease.
It's what pro-active pet parenting is all about.