infections
Defenses Against Infection
The Blood
The body also defends against infection by increasing the number of certain types of white blood cells ( Neutrophils and The number of Eosinophils , another type of white blood cell, increases in allergic reactions and many parasitic infections, but usually not in bacterial infections. However, certain infections, such as Typhoid Fever , viral infections, and bacterial infections that overwhelm the immune system, can lead to a decrease in the white blood cell count. 