Rabies is a viral disease that may infect any warm-blooded animal. Regardless of the initial site of virus introduction into the animal, the virus eventually invades the central nervous system. With rare exception, it is a fatal disease.
Your veterinarian has recommended some bloodwork for your pet. Maybe your pet is ill. Maybe your pet looks perfectly fine to you. You’re not sure why your pet really needs to have these tests. Although your pet may look and act normally, they are very adept at hiding illnesses. Sometimes they have not begun to feel the effects of some minor but perhaps very significant changes. A blood chemistry panel (see our Archives for a discussion of the chemistry panel) will evaluate the organ systems. Another part of the bloodwork which is usually recommended is the Complete Blood Count (CBC). The CBC involves a number of parameters evaluating the blood and bone marrow and their responses to changes throughout the body.
These cells are evaluated for their number, packed cell volume (PCV), their mean cell volume, their mean hemoglobin (Hb) content, their mean Hb concentration, and their size, shape, and color. The most common problem revealed by these parameters is anemia, and the various parameters can help classify the type of anemia present. The causes of anemia can be divided into 3 general categories: blood loss, hemolysis (destruction of red blood cells), or decreased production within the bone marrow.
These cells are immature red blood cells. An increased number of reticulocytes in the bloodstream indicates regeneration, whereby the bone marrow is generating new red blood cells to replace those being lost. Once the bone marrow becomes activated, it takes at least 3 days before reticulocytes appear in the circulation.
This class of cells encompasses a number of different cell types which indicate infection or inflammation in general.
Neutrophils can be increased by stress or fear, inflammation or infection, and some forms of cancer. Their numbers can be depleted by severe systemic inflammation or infection, certain toxins or drugs, immune-mediated destruction (where the body attacks its own cells), irradiation, and bone marrow cancer. Segmented neutrophils are seen in cases of overwhelming disease. Monocytes may be increased by steroid administration, inflammation or infection, and bone marrow cancer. Eosinophils are commonly increased by the presence of parasites, by allergy or inflammation, and in relation to various cancers. Steroids can cause a decrease in the number of these cells. Basophils can be increased by parasitic infestation, allergy, and certain cancers. Lymphocytes can be increased by stress, infection, and cancer (such as lymphoma) and can be decreased by steroids, viral infection, damage to the lymphatic vessels, and congential defects in certain dog breeds.
The function of these cells is to control bleeding. When an animal’s platelet count becomes too low, they are susceptible to hemorrhaging. A low platelet count can substantially increase an animal’s risk for surgery. Low platelet counts can be due to immune-mediated damage, increased consumption due to infection, hemorrhage, severe clotting within the blood vessel, excessive storage within the spleen, certain drugs, and bone marrow disease.
As you can see the CBC gives your veterinarian a lot of information regarding your pet’s overall health and can help pinpoint problem areas. Even if your pet is not currently ill, a baseline CBC (as well as a chemical profile) is good to have. It can help your veterinarian check your pet’s progress through illnesses and aging. If you have questions pertaining to your individual pet, please call your veterinarian for advice.