Antonio Turner II
Bacterial Diseases of the Cardiovascular and Lymphatic Systems
Dr. Ashraf Dec. 4, 2017

The infectious diseases of the cardiovascular system infect the blood, blood vessels, and heart. In many cases, the infections remain in these areas, but in others, the infections are spread to secondary organs. The diseases of the lymphatic system affect the lymph, lymph vessels, lymph nodes, and lymphoid organs, such as the spleen, tonsils, and thymus.
Streptococcal septicemia. Septicemia is a general expression for microbial infection of the blood and blood vessels. In previous generations, this condition was known as blood poisoning. A common cause of streptococcal septicemia is the Gram-positive streptococcus named Streptococcus pyogenes. This beta-hemolytic streptococcus causes severe fever, malaise, and dropping blood pressure. Shock may accompany the infection, and antibiotic therapy with penicillin is used aggressively. Septicemia may also be caused by a number of Gram negative rods that release endotoxins. An important complication of streptococcal septicemia is endocarditis, an infection of the heart valves. This is usually an immune system problem caused by antigen-antibody reactions taking place at the heart valves. Heart valve replacement is sometimes required. The subacute form due to Streptococcus pyogenes is accompanied by fever, weakness, and heart murmur. The acute form is generally due to infection by Staphylococcus aureus and is accompanied by rapid d estruction of the heart valves. Rheumatic fever is an immune reaction taking place in the heart tissues and is usually stimulated by antigens derived from Streptococcus pyogenes. Inflammation of the heart tissues is often accompanied by inflammation and arthritis of the joints, a condition called rheumatoid arthritis. A streptococcal sore throat may precede this condition.
Tularemia. Tularemia is due to a Gram-negative rod called Francisella tularensis. The bacteria enter the body by contact, inhalation, ingestion of contaminated rabbit meat, and the bite of ticks and other arthropods. Patients experience a blood disorder accompanied by fever, malaise, and numerous nonspecific symptoms. Antibiotics such as gentamicin are used in therapy. Plague. Plague is caused by the Gram-negative rod Yersinia pestis. This organism is similar to the agent of tularemia and is transmitted by its rodent reservoir, the rat flea. The organism enters the lymphatic system and causes swelling of the lymph nodes called buboes. This stage is called bubonic plague. When the bacteria enter the blood, the condition is referred to as septicemic plague, and when the bacteria enter the lungs, the disease is called pneumonic plague. Transmission by airborne droplets is possible at this time. Aggressive antibiotic therapy is necessary to prevent death. The bacteria display a safety-pin appearance due to the accumulation of dye at the poles of the cells. This characteristic is called bipolar staining. Brucellosis. Brucellosis is also known as undulant fever because it is characterized by alternating periods of high fever and relief. The bacterial agents belong to the genus Brucella . They are small, Gram negative rods and include B. abortus, B. suis, B. melitensis , and B. canis. In animals, these bacteria cause abortion of the young (contagious abortion) and sterility of the female. They are transmitted to humans by unpasteurized milk and contaminated meat. On entering the bloodstream, the bacteria cause fever, chills, and malaise. Prolonged treatment is required with tetracycline, and vaccines are available f or immunizing herds of animals. Anthrax. Anthrax is due to the Gram-positive, aerobic, spore forming rod Bacillus anthracis. Spores from this organism are inhaled from the air, or they are acquired during contact with contaminated soil or animals such as sheep and cattle. In the bloodstream, B. anthracis causes severe hemorrhaging, and the spleen, kidneys, and other blood rich organs become engorged with blood. In the lungs, anthrax is called wool sorter's disease and is accompanied by pneumonia. Aggressive antibiotic therapy is necessary to prevent death. Relapsing fever. Relapsing fever is so named because of the recurrent periods of fever. The etiologic agent is Borrelia recurrentis , which is a spirochete. The organism is transmitted by lice, which are natural parasites of humans. It may also be transmitted among humans by ticks. Jaundice and rose-colored skin spots accompany the infection, which may be t reated by antibiotics. Lyme disease. Lyme disease is caused by Borrelia burgdorferi. This organism is a spirochete transmitted by ticks of the genus Ixodes. First observed in Lyme, Connecticut, Lyme disease is now found throughout the United States.
Among the first symptoms of Lyme disease is a bull's-eye rash occurring on the skin. The rash is called erythema chronicum migrans. It occurs at the site of the tick bite and has a