General Information: This strain is an asymptomatic carrier strain that was serum-resistant. Causes disease in cattle. A group of organisms that are either obligate parasites or commensal organisms found in animal mucous membranes. Almost all species require the presence of important growth factors found in the blood of their hosts, including either X factor (protoporphyrin IX or heme) or V factor (nicotinamide adenine dinucleotide (NAD or NADP)). This organism is a major cause of disease in feedlot cattle. It causes constriction of blood vessels supplying major organs, restricting blood supply which leads to reduced oxygen delivery, and leads to tissue damage and death. The diseases that result are pneumonia, arthritis, myocarditis (inflammation of heart muscle), and reproductive problems resulting in the loss of millions of dollars in animals each year.