15.9: Viral Diseases of the Cardiovascular and Lymphatic Systems - Biology

15.9: Viral Diseases of the Cardiovascular and Lymphatic Systems - Biology

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15.9: Viral Diseases of the Cardiovascular and Lymphatic Systems

15.9: Viral Diseases of the Cardiovascular and Lymphatic Systems - Biology

Leishmaniasis is a disease transmitted by the bite of a female sandfly. There various types of leishmaniasis that exist including cutaneous leishmaniasis, systemic, or visceral leishmaniasis. Cutaneous leishmaniasis is characterized by infection of the skin and mucous membranes. The symptoms include skin sores which present at the site of the sandfly bite. In addition, cutaneous leishmaniasis includes breathing difficulty, stuffy nose, runny nose, nose bleeds, swallowing difficulty and ulcers in the mouth, tongue, gums, lips, nose, and inner nose. Systemic or visceral leishmaniasis present as an infection of the entire body. There is a delay of symptoms, ranging from 2-8 months post bite, and the effects on the immune system can result in deadly complications. The parasites damage the immune system by targeting the disease-fighting cells. Symptoms present much more quickly in children and include a cough, diarrhea, fever, and vomiting. In adults, there is fatigue, weakness, loss of appetite, abdominal pain, night sweats, fever, weight loss, and changes in the color and texture of the skin. In combination, cutaneous and visceral leishmaniasis are caused by more than 20 different leishmanial species.

Leishmaniasis: A Phlebotomus papatasi sand fly that transmits one type of leishmaniasis, next to an image of Leishmania sp. promastigotes from culture. This is the stage of the parasite that occurs inside the mid-gut of the sand fly.

Leishmaniasis is vector-borne because it is transmitted via a bite from a sandfly. The sandflies that cause leishmaniasis are infected by an obligate intracellular protozoa of the genus Leishmania. The species of Leishmania that can cause leishmaniasis include: L. donovani complex with 2 species (L. donovani, L. infantum, also known as L. chagasi) the L. mexicana complex with 3 main species (L. mexicana, L. amazonensis, and L. venezuelensis) L. tropica L. major L. aethiopica and the subgenus Viannia with 4 main species (L. (V.) braziliensis, L. (V.) guyanensis, L. (V.) panamensis, and L. (V.) peruviana). These various species are indistinguishable via morphology but can be identified using advanced techniques such as isoenzyme analysis.

Leishmaniasis is transmitted by the bite of infected female phlebotomine sandflies which can transmit the infection Leishmania. The sandflies inject the infective stage, metacyclic promastigotes, during blood meals. Metacyclic promastigotes that reach the puncture wound are phagocytized by macrophages and transform into amastigotes. Amastigotes multiply in infected cells and affect different tissues, depending in part on which Leishmania species is involved. These differing tissue specificities cause the differing clinical manifestations of the various forms of leishmaniasis. Sandflies become infected during blood meals on infected hosts when they ingest macrophages infected with amastigotes. In the sandfly’s midgut, the parasites differentiate into promastigotes, which multiply, differentiate into metacyclic promastigotes, and migrate to the proboscis.

Leishmaniasis life cycle: Leishmaniasis is a vector-borne disease and is transmitted by the sand fly.

15.9: Viral Diseases of the Cardiovascular and Lymphatic Systems - Biology

Cardiovascular, Lymphatic and Systemic Infections

  • Blood consists of several different types of cells.
  • Red blood cells are also called erythrocytes.
  • The cells are suspended in plasma.
  • Red blood cells carry oxygen.
  • White blood cells are also called leukocytes and are used to fight disease.
  • Platelets are involved in blood clotting.
  • The heart is a muscle that acts like a pump.
  • Consists of a closed system where blood is pumped by the heart.
  • The heart pumps blood into arteries, veins carry blood back to the heart.
  • The major arteries are the pulmonary arteries which carry blood to the lungs and the aorta that take the blood to the remaining parts of the body.
  • The major veins are: pulmonary veins which carry blood from the lungs to the heart, superior vena cava head neck and arms to heart and inferior vena cava from the rest of the body to the heart.
  • The heart itself is supplied by coronary arteries which come from the aorta and cardiac veins which drain into the left atrium.
  • The human heart is a muscle with four chambers.
  • The heart is enclosed in a pericardial sac that is lined with a serous membrane. The pericardial sac is an important target for infection or inflammation by microbes.
  • The wall of the heart is made up of an outer, fibrous pericardium, muscular myocardium and inner endocardium.
  • Chambers of the Heart: The internal cavity of the heart is divided into four chambers: right & left atrium, right & left ventricle.
  • The right atrium receives deoxygenated blood from systemic veins the left atrium receives oxygenated blood from the pulmonary veins.
  • The valves of the heart are another target for microbial infection. The valves keep the fluid flowing in one direction.
  • The heart acts like two pumps, one on the right and one on the left.
  • Blood goes from the right atrium to the right ventricle, and then is pumped to the lungs where it is oxygenated.
  • From the lungs the blood goes to the left atrium and then to the left ventricle. From there it is pumped to the body for systemic circulation.
  • The lymphatic system is a network of lymphoid organs, lymph nodes, ducts, tissues, vessels and fluid.
  • The lymphatic system is an important component of the immune system.
  • There are three functions of the lymphatic system: removes excess fluid from body tissues, absorbs fatty acids and takes them to the circulatory system and finally make immune cells such as lymphocytes, monocytes and antibody producing cells called plasma cells.
  • The lymphatic system is made up of thin vessels that branch throughout the body similar to the blood system. The vessels carry a clear liquid called “lymph”. Blood plasma leaks from the capillaries of the blood circulatory system and fill the spaces between the cells of tissue, this is called interstitial fluid. The fluid accumulates slowly and is similar to the blood plasma. Most is returned to the circulatory system via the capillaries. Lymph has a large number of white blood cells. The remaining fluid, about 10% is collected as lymph (or lymphatic fluid which is colorless) by the lymphatic system. It is processed by the lymph nodes before it returns to the circulatory system.
  • Lymph nodes are bean shaped and function as filters. They are filled with lymphocytes (white blood cells) which increase rapidly when fighting an infection.
  • Pathogens and toxins that target vulnerabilities of the cardiovascular and lymphatic systems can spread throughout the body to cause what is referred to as systemic diseases. Several different pathogens are profiled that demonstrate these concepts.

The structure and function of the cardiovascular and lymphatic systems are introduced. Infections of both systems are described and how infections involving these systems can lead to what is referred to as systemic infections. Systemic infections are those that spread beyond a specific organ system like digestive, respiratory etc. Systemic infections have spread throughout the body.

  • Detailed description of and graphical representation of the cardiovascular system.
  • Detailed description and graphical representation of the lymphatic system.
  • The structure of blood is presented in an animated step by step process.
  • Concept map showing inter-connections of new concepts in this tutorial and those previously introduced.
  • Definition slides introduce terms as they are needed.
  • Visual representation of concepts
  • Animated examples—of concepts are used to step wise breakdown a concepts.
  • A concise summary is given at the conclusion of the tutorial.

Basic structure and function of the cardiovascular system.
Basic structure and function of the lymphatic system.
How the structures of the cardiovascular and lymphatic system are affected by microbial diseases.
Bacterial cardiovascular and systemic diseases.
Viral cardiovascular and systemic diseases.
Cardiovascular and systemic diseases caused by protozoans and helminthic organisms.

See all 24 lessons in Anatomy and Physiology, including concept tutorials, problem drills and cheat sheets: Teach Yourself Microbiology Visually in 24 Hours

Chapter 18 Homework

2) 2.1 MILLION new infections occurred in 2013, but there has been a 19% DECREASE in new infections in the US in recent years.

3) In most parts of the world, HETEROSEXUAL intercourse is the primary mode of transmission for HIV, with rates increasing dramatically in adolescent and young adult FEMALE populations.

4) IN large metropolitan areas worldwide, infection from the use of contaminated NEEDLES during drug use is growing more rapidly than any other mode of transmission, which greatly influences the rate of sexual form of transmission as well.

RMSF - an ibm employee returns from a June team-building exercise in the mountains of NC, he develops flue-like symptoms followed by a rash on his wrist and ankles

INFECTIOUS MONONUCLEOSIS - a 17 year old boy develops a high fever, lethargy, sore throat and swollen glands, a blood count shows large atypical lymphocytes

LYME DISEASE - spirochete is transmitted by hard ticks and an early symptom is a lesion that looks like a bull's eye

PLAGUE - the bacterium is inject by the bite of a flea, enters the lymph, and is trapped in a lymph node where it results in a swollen necrotic lesion called a bubo.

Top Right: drugs that block viral replication during viral DNA synthesis (AZT)

Middle: drugs that block the final assembly and maturation of new virus particles

1% -- percentage of HIV+ individuals who are nonprogressors

90% -- percentage of world's population infected with EBV

2) The asexual phase begins when the human is bitten by an Anopheles mosquito, injecting the SPOROZOITES into the capillaries along with an anticoagulant. The cells circulate and enter the liver where they undergo SCHIZOGONY a form of asexual division producing numerous MEROZOITES within the hepatocytes.

3) When the liver cell ruptures, thousands of merozoites enter the circulation where they infect erythrocytes and convert to TROPHOZOITES. Lysis of erythrocytes releases more merozoites, and this ERYTHROCYTIC phase is responsible for the synchronous symptoms seen in the infected host.

2) The virus then enters the cell through the process of ENDOCYTOSIS and then UNCOATS

3) The enzyme REVERSE TRANSCRIPTASE then converts viral RNA into DNA

4) The newly synthesized nucleic acid can enter the host cell genome through the action of the viral enzyme INTEGRASE, leading to a period called latency.

5) The integrated viral genome, or the PROVIRUS, can be reactivated leading to the production of viral mRNA


Occurring in the long standing cases of primary or secondary lymphedema, it is a rare disorder that is characterized by the growth of a malignant tumor. However, the initial signs involve the appearance of a purplish discoloration or a bruise mark, and gradually progresses to an ulcer with crusting and, finally, results in extensive necrosis. The treatment usually depends on the type and severity of the malignancy. In case of metastasis, chemotherapy may be administered, and in some other cases, amputation of the affected limb is considered to be the most successful therapy.

Dr. Bukhtiar Shah

Scientific Review Officer

The IVPP study section reviews applications focused on endothelial cells, blood vessels and lymphatics and their role in normal physiology and disease. Cellular, biochemical, biophysical, immunological, genetic, pharmacological, and molecular biological approaches are typical. Basic and applied aspects of cardiovascular regulation are reviewed that focus on the physiology of blood pressure regulation, the pathogenesis of hypertension and the microcirculation, biology of the endothelium and vascular smooth muscle cells and vascular homeostasis and dysfunction in experimental models. Studies on cell surface receptors and signaling processes of various hormones, paracrines, and autocrines and their mechanisms of action as related to hypertension, integrated neural-humoral control of circulation, regional hemodynamics, lymphatic circulation, and microcirculation are also considered.

Review Dates

15.9: Viral Diseases of the Cardiovascular and Lymphatic Systems - Biology

Barbara is a 43-year-old patient who has been diagnosed with metastatic inflammatory breast cancer. To facilitate her ongoing chemotherapy, her physician implanted a port attached to a central venous catheter. At a recent checkup, she reported feeling restless and complained that the site of the catheter had become uncomfortable. After removing the dressing, the physician observed that the surgical site appeared red and was warm to the touch, suggesting a localized infection. Barbara’s was also running a fever of 38.2 °C (100.8 °F). Her physician treated the affected area with a topical antiseptic and applied a fresh dressing. She also prescribed a course of the antibiotic oxacillin.

  • Based on this information, what factors likely contributed to Barbara’s condition?
  • What is the most likely source of the microbes involved?

Jump to the next Clinical Focus box.

The circulatory and lymphatic systems are networks of vessels and a pump that transport blood and lymph, respectively, throughout the body. When these systems are infected with a microorganism, the network of vessels can facilitate the rapid dissemination of the microorganism to other regions of the body, sometimes with serious results. In this section, we will examine some of the key anatomical features of the circulatory and lymphatic systems, as well as general signs and symptoms of infection.

The Circulatory System

The circulatory (or cardiovascular) system is a closed network of organs and vessels that moves blood around the body ([link]). The primary purposes of the circulatory system are to deliver nutrients, immune factors, and oxygen to tissues and to carry away waste products for elimination. The heart is a four-chambered pump that propels the blood throughout the body. Deoxygenated blood enters the right atrium through the superior vena cava and the inferior vena cava after returning from the body. The blood next passes through the tricuspid valve to enter the right ventricle. When the heart contracts, the blood from the right ventricle is pumped through the pulmonary arteries to the lungs. There, the blood is oxygenated at the alveoli and returns to the heart through the pulmonary veins. The oxygenated blood is received at the left atrium and proceeds through the mitral valve to the left ventricle. When the heart contracts, the oxygenated blood is pumped throughout the body via a series of thick-walled vessels called arteries. The first and largest artery is called the aorta. The arteries sequentially branch and decrease in size (and are called arterioles) until they end in a network of smaller vessels called capillaries. The capillary beds are located in the interstitial spaces within tissues and release nutrients, immune factors, and oxygen to those tissues. The capillaries connect to a series of vessels called venules, which increase in size to form the vein s. The veins join together into larger vessels as they transfer blood back to the heart. The largest veins, the superior and inferior vena cava, return the blood to the right atrium.

The major components of the human circulatory system include the heart, arteries, veins, and capillaries. This network delivers blood to the body’s organs and tissues. (credit top left: modification of work by Mariana Ruiz Villareal credit bottom right: modification of work by Bruce Blaus)

Other organs play important roles in the circulatory system as well. The kidneys filter the blood, removing waste products and eliminating them in the urine. The liver also filters the blood and removes damaged or defective red blood cells. The spleen filters and stores blood, removes damaged red blood cells, and is a reservoir for immune factors. All of these filtering structures serve as sites for entrapment of microorganisms and help maintain an environment free of microorganisms in the blood.

The Lymphatic System

The lymphatic system is also a network of vessels that run throughout the body ([link]). However, these vessels do not form a full circulating system and are not pressurized by the heart. Rather, the lymphatic system is an open system with the fluid moving in one direction from the extremities toward two drainage points into veins just above the heart. Lymphatic fluids move more slowly than blood because they are not pressurized. Small lymph capillaries interact with blood capillaries in the interstitial spaces in tissues. Fluids from the tissues enter the lymph capillaries and are drained away ([link]). These fluids, termed lymph , also contain large numbers of white blood cells.

The essential components of the human lymphatic system drain fluid away from tissues. Blood enters the capillaries from an arteriole (red) and leaves through venules (blue). Interstitial fluids may drain into the lymph capillaries (green) and proceed to lymph nodes. (credit: modification of work by National Cancer Institute, National Institutes of Health)

The lymphatic system contains two types of lymphoid tissues. The primary lymphoid tissue includes bone marrow and the thymus. Bone marrow contains the hematopoietic stem cells (HSC) that differentiate and mature into the various types of blood cells and lymphocytes (see [link]). The secondary lymphoid tissue s include the spleen, lymph nodes, and several areas of diffuse lymphoid tissues underlying epithelial membranes. The spleen , an encapsulated structure, filters blood and captures pathogens and antigens that pass into it ([link]). The spleen contains specialized macrophages and dendritic cells that are crucial for antigen presentation, a mechanism critical for activation of T lymphocytes and B lymphocytes (see Major Histocompatibility Complexes and Antigen-Presenting Cells). Lymph nodes are bean-shaped organs situated throughout the body. These structures contain areas called germinal centers that are rich in B and T lymphocytes. The lymph nodes also contain macrophages and dendritic cells for antigen presentation. Lymph from nearby tissues enters the lymph node through afferent lymphatic vessels and encounters these lymphocytes as it passes through the lymph exits the lymph node through the efferent lymphatic vessels ([link]).

(a) The spleen is a lymphatic organ located in the upper left quadrant of the abdomen near the stomach and left kidney. It contains numerous phagocytes and lymphocytes that combat and prevent circulatory infections by killing and removing pathogens from the blood. (b) Lymph nodes are masses of lymphatic tissue located along the larger lymph vessels. They contain numerous lymphocytes that kill and remove pathogens from lymphatic fluid that drains from surrounding tissues.

The lymphatic system filters fluids that have accumulated in tissues before they are returned to the blood. A brief overview of this process is provided at this website.

Infections of the Circulatory System

Under normal circumstances, the circulatory system and the blood should be sterile the circulatory system has no normal microbiota. Because the system is closed, there are no easy portals of entry into the circulatory system for microbes. Those that are able to breach the body’s physical barriers and enter the bloodstream encounter a host of circulating immune defenses, such as antibodies, complement proteins, phagocytes, and other immune cells. Microbes often gain access to the circulatory system through a break in the skin (e.g., wounds, needles, intravenous catheters, insect bites) or spread to the circulatory system from infections in other body sites. For example, microorganisms causing pneumonia or renal infection may enter the local circulation of the lung or kidney and spread from there throughout the circulatory network.

If microbes in the bloodstream are not quickly eliminated, they can spread rapidly throughout the body, leading to serious, even life-threatening infections. Various terms are used to describe conditions involving microbes in the circulatory system. The term bacteremia refers to bacteria in the blood. If bacteria are reproducing in the blood as they spread, this condition is called septicemia . The presence of viruses in the blood is called viremia . Microbial toxins can also be spread through the circulatory system, causing a condition termed toxemia .

Microbes and microbial toxins in the blood can trigger an inflammatory response so severe that the inflammation damages host tissues and organs more than the infection itself. This counterproductive immune response is called systemic inflammatory response syndrome (SIRS) , and it can lead to the life-threatening condition known as sepsis . Sepsis is characterized by the production of excess cytokines that leads to classic signs of inflammation such as fever, vasodilation , and edema (see Inflammation and Fever). In a patient with sepsis, the inflammatory response becomes dysregulated and disproportionate to the threat of infection. Critical organs such as the heart, lungs, liver, and kidneys become dysfunctional, resulting in increased heart and respiratory rates, and disorientation. If not treated promptly and effectively, patients with sepsis can go into shock and die.

Certain infections can cause inflammation in the heart and blood vessels. Inflammation of the endocardium, the inner lining of the heart, is called endocarditis and can result in damage to the heart valves severe enough to require surgical replacement. Inflammation of the pericardium, the sac surrounding the heart, is called pericarditis . The term myocarditis refers to the inflammation of the heart’s muscle tissue. Pericarditis and myocarditis can cause fluid to accumulate around the heart, resulting in congestive heart failure. Inflammation of blood vessels is called vasculitis . Although somewhat rare, vasculitis can cause blood vessels to become damaged and rupture as blood is released, small red or purple spots called petechiae appear on the skin. If the damage of tissues or blood vessels is severe, it can result in reduced blood flow to the surrounding tissues. This condition is called ischemia , and it can be very serious. In severe cases, the affected tissues can die and become necrotic these situations may require surgical debridement or amputation.

  • Why does the circulatory system have no normal microbiota?
  • Explain why the presence of microbes in the circulatory system can lead to serious consequences.

Infections of the Lymphatic System

Like the circulatory system, the lymphatic system does not have a normal microbiota, and the large numbers of immune cells typically eliminate transient microbes before they can establish an infection. Only microbes with an array of virulence factors are able to overcome these defenses and establish infection in the lymphatic system. However, when a localized infection begins to spread, the lymphatic system is often the first place the invading microbes can be detected.

Infections in the lymphatic system also trigger an inflammatory response. Inflammation of lymphatic vessels, called lymphangitis , can produce visible red streaks under the skin. Inflammation in the lymph nodes can cause them to swell. A swollen lymph node is referred to as a bubo , and the condition is referred to as lymphadenitis .

Key Concepts and Summary

  • The circulatory system moves blood throughout the body and has no normal microbiota.
  • The lymphatic system moves fluids from the interstitial spaces of tissues toward the circulatory system and filters the lymph. It also has no normal microbiota.
  • The circulatory and lymphatic systems are home to many components of the host immune defenses.
  • Infections of the circulatory system may occur after a break in the skin barrier or they may enter the bloodstream at the site of a localized infection. Pathogens or toxins in the bloodstream can spread rapidly throughout the body and can provoke systemic and sometimes fatal inflammatory responses such as SIRS, sepsis, and endocarditis.
  • Infections of the lymphatic system can cause lymphangitis and lymphadenitis.

Multiple Choice

Which term refers to an inflammation of the blood vessels?

Which of the following is located in the interstitial spaces within tissues and releases nutrients, immune factors, and oxygen to those tissues?

Which of these conditions results in the formation of a bubo?

Which of the following is where are most microbes filtered out of the fluids that accumulate in the body tissues?

Fill in the Blank

Vasculitis can cause blood to leak from damaged vessels, forming purple spots called ________.

The lymph reenters the vascular circulation at ________.

Short Answer

How do lymph nodes help to maintain a microbial-free circulatory and lymphatic system?

Critical Thinking

What term refers to the red streaks seen on this patient’s skin? What is likely causing this condition?

(credit: modification of work by Centers for Disease Control and Prevention)

Why would septicemia be considered a more serious condition than bacteremia?

Transformation of Cells in Culture

The study of tumor induction by radiation, chemicals, or viruses requires experimental systems in which the effects of a carcinogenic agent can be reproducibly observed and quantitated. Although the activity of carcinogens can be assayed in intact animals, such experiments are difficult to quantitate and control. The development of in vitro assays to detect the conversion of normal cells to tumor cells in culture, a process called cell transformation, therefore represented a major advance in cancer research. Such assays are designed to detect transformed cells, which display the in vitro growth properties of tumor cells, following exposure of a culture of normal cells to a carcinogenic agent. Their application has allowed experimental analysis of cell transformation to reach a level of sophistication that could not have been attained by studies in whole animals alone.

The first and most widely used assay of cell transformation is the focus assay, which was developed by Howard Temin and Harry Rubin in 1958. The focus assay is based on the ability to recognize a group of transformed cells as a morphologically distinct 𠇏ocus” against a background of normal cells on the surface of a culture dish (Figure 15.12). The focus assay takes advantage of three properties of transformed cells: altered morphology, loss of contact inhibition, and loss of density-dependent inhibition of growth. The result is the formation of a colony of morphologically altered transformed cells that overgrow the background of normal cells in the culture. Such foci of transformed cells can usually be detected and quantified within a week or two after exposure to a carcinogenic agent. In general, cells transformed in vitro are able to form tumors following inoculation into susceptible animals, supporting in vitro transformation as a valid indicator of the formation of cancer cells.

Figure 15.12

The focus assay. A focus of chicken embryo fibroblasts induced by Rous sarcoma virus. (From H. M. Temin and H. Rubin, 1958. Virology 6: 669.)

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Table of contacts

Chapter 1 The Main Themes of Microbiology

Chapter 2 The Chemistry of Biology

Chapter 3 Tools of the Laboratory: Methods for the Culturing of Microscopic Analysis of Microorganisms

Chapter 4 Bacteria and Archaea

Ch apter 5 Eukaryotic Cells and Microorganisms

Chapter 6 Viruses and Prions

Chapter 7 Microbial Nutrition and Growth

Chapter 8 Microbial Metabolism: The Chemical Crossroads of Life

Chapter 9 Microbial Genetics

Chapter 10 Genetic Analysis and Genetic Engineering

Chapter 11 Physical and Chemical Control of Microbes

Chapter 12 Antimicrobial Treatment

Chapter 13 Microbe-Human Interactions: Health and Disease

Chapter 14 Host Defenses I: Overview and Nonspecific Defenses

Chapter 15 Host Defenses II: Specific Immunity and Immunization

Chapter 16 Disorders in Immunity

Chapter 17 Diagnosing Infections

Chapter 18 Infectious Diseases Affecting the Skin and Eyes

Chapter 19 Infectious Diseases Affecting the Nervous System

Chapter 20 Infectious Diseases Affecting the Cardiovascular and Lymphatic Systems

Chapter 21 Infectious Diseases Affecting the Respiratory System

Chapter 22 Infectious Diseases Affecting the Gastrointestinal Tract

Chapter 23 Infectious Diseases Affecting the Genitourinary System

Chapter 24 Microbes and the Environment

Chapter 25 Applied Microbiology and Food and Water Safety

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