Microbiology: A Systems Approach, 2 nd ed. Chapter 20: Infectious Diseases Affecting the Cardiovascular and Lymphatic Symptoms
Microbiology: A Systems Approach, 2nd ed.
Chapter 20: Infectious Diseases Affecting the Cardiovascular and
Lymphatic Symptoms
20.1 The Cardiovascular and Lymphatic Systems and Their Defenses
• Cardiovascular System– Blood vessels and heart– Moves blood in a closed circuit– Also known as the circulatory system– Provides tissues with oxygen and nutrients and
carries away carbon dioxide and waste products
The Heart• Divided into two halves, each half divided into an
upper and lower chamber• Upper chambers: atria; lower chambers:
ventricles• Covered by the pericardium• Three layers to the wall of the heart (from outer
to inner)– Epicardium– Myocardium– Endocardium
Figure 20.1
Figure 20.2
Lymphatic System
• One-way passage• Returns fluids from the tissues to the
cardiovascular system
Figure 14.10
Defenses of the Cardiovascular and Lymphatic Systems
• Cardiovascular system is highly protected, however, if microbes do invade they gain access to every part of the body
• Bloodstream infections are systemic infections; often with the suffix –emia– Viremia– Fungemia– Bacteremia – Septicemia (can lead to septic shock)
• Defenses in the bloodstream- leukocytes
20.2 Normal Biota of the Cardiovascular and Lymphatic Systems
• None• Some microorganisms may be present
transiently (filtering out of tissues) but they do not colonize the systems in the healthy state
20.3 Cardiovascular and Lymphatic System Diseases Caused by
Microorganisms• Endocarditis
– Inflammation of the endocardium– Usually refers to an infection of the valves of the heart– Acute and subacute, with similar symptoms (in subacute
the symptoms develop more slowly and are less pronounced)
– Fever, anemia, abnormal heartbeat– Sometimes symptoms similar to heart attack– Abdominal or side pain may be reported– Petechiae over the upper half of the body and under the
fingernails may be present– In subacute cases, may have enlarged spleen
Figure 20.3
Septicemias• Occurs when organisms are actively multiplying in the
blood• Many different bacteria and a few fungi can cause this
condition• Fever- prominent symptom• Patient appears very ill, may have an altered mental
state, shaking chills, and gastrointestinal symptoms• Often exhibits increased breathing rate and respiratory
alkalosis• Low blood pressure
Plague• Three possible manifestations
– Pneumonic plague: respiratory disease– Bubonic plague
• Bacterium injected through a flea bite• Enters the lymph and is filtered by a lymph node• Infection causes inflammation and necrosis of the node• Results in a swollen lesion called a bubo, usually in the groin
or axilla• Incubation period: 2 to 8 days, ending with the onset of
fever, chills, headache, nausea, weakness, and tenderness of the bubo
– Septicemic plague: when the case progresses to massive bacterial growth in the blood
Figure 20.4
Figure 20.5
Figure 20.6
Tularemia• Sometimes called rabbit fever, because it has been
associated with outbreaks of disease in wild rabbits• Pathogen of concern on the lists of bioterrorism agents• Tick bites: most frequent arthropod vector• Incubation period of a few days to 3 weeks• Symptoms: headache, backache, fever, chills, malaise,
and weakness• Further symptoms tied to the portal of entry:
ulcerative skin lesions, swollen lymph glands, conjunctival inflammation, sore throat, intestinal disruption, pulmonary involvement
Lyme Disease
• Nonfatal• Evolves into a slowly progressive syndrome
that mimics neuromuscular and rheumatoid conditions
• Early symptom: rash a the site of a tick bite• Other early symptoms: fever, headache, stiff
neck, and dizziness• Second stage: cardiac and neurological
symptoms develop
Figure 20.7
Figure 20.8
Figure 20.9
Figure 20.10
Infectious Mononucleosis• Majority caused by Epstein-Barr virus (EBV)• Most of the remainder caused by
cytomegalovirus (CMV)• Sore throat, high fever, and cervical
lymphadenopathy• Long incubation period- 30 to 50 days• Also may exhibit a gray-white exudates in the
throat, skin rash, and enlarged spleen and liver• Sudden leukocytosis• Fatigue
Figure 20.11
Hemorrhagic Fever Diseases
• Caused by viruses in one of four families:• Arenaviridae• Filoviridae• Flaviviridae• Bunyaviridae
Yellow Fever
• Capillary fragility• Disrupts the blood-clotting system• Begins with fever, headache, and muscle pain• Sometimes progresses to oral hemorrhage,
nosebleed, vomiting, jaundice, and liver and kidney damage
Dengue Fever
• Usually mild• Sometimes it can progress to dengue
hemorrhagic shock syndrome• Causes severe pain in muscles and joints
Ebola and Marburg
• Related viruses, cause similar symptoms• Extreme manifestations of of hemorrhagic
events with extensive capillary fragility and disruption of clotting
• Patients bleed from their orifices, mucous membranes, and experience massive internal and external hemorrhage
• Often manifest a rash on the trunk in early stages
Lassa Fever
• Most cases asymptomatic• In 20% of the cases a severe hemorrhagic
syndrome develops• Chest pain, hemorrhaging, sore throat, back
pain, vomiting, diarrhea, and sometimes encephalitis
• Patients who recover often suffer from deafness
Nonhemorrhagic Fever Diseases
• Brucellosis– On the CDC list of possible bioterror agents– Bacteria is carried into the bloodstream by
phagocytic cells, creating focal lesions in the liver, spleen, bone marrow, and kidney
– Fluctuating pattern of fever accompanied by chills, profuse sweating, headache, muscle pain and weakness, and weight loss
Figure 20.12
Q Fever
• Abrupt onset of fever, chills, head and muscle ache, and occasionally a rash
• Sometimes complicated by pneumonitis, hepatitis, and endocarditis
Figure 20.13
Cat-Scratch Disease
• Symptoms start after 1 to 2 weeks• Cluster of small papules at the site of
inoculation• In a few weeks, lymph nodes swell and can
become pus-filled• Only about 1/3 of patients experience high
fever
Figure 20.14
Trench Fever
• Highly variable symptoms• 5- to 6-day fever• Leg pains, especially in the tibial region• Headache, chills, and muscle aches• Macular rash can occur• Endocarditis can develop
HGA and HME
• Similar signs and symptoms• Acute febrile state • Headache, muscle pain, and rigors
Rocky Mountain Spotted Fever (RMSF)
• 2 to 4 days incubation• First symptoms: sustained fever, chills,
headache, and muscular pain• Distinctive spotted rash within 2 to 4 days after
the prodrome• In most severe untreated cases, enlarged lesions
merge and become necrotic• Other manifestations: cardiovascular disruption;
conditions of restlessness, delirium, convulsions, tremor, and coma
Figure 20.15
Figure 20.16
Malaria
• The world’s dominant protozoan disease• 10- to 16-day incubation period• First symptoms: malaise, fatigue, vague aches,
and nausea with or without diarrhea• Next symptoms: bouts of chills, fever, and
sweating• Symptoms occur at 48- or 72-hour intervals• The interval, length, and regularity of symptoms
reflect the type of malaria
Figure 20.17
Figure 20.18
Figure 20.19
Anthrax
• Can exhibit its primary sumptoms in various locations of the body– Cutaneous anthrax– Pulmonary anthrax– Gastrointestinal tract– Anthrax meningitis
• Cutaneous and pulmonary forms most common
Figure 20.20
HIV Infection and AIDS• Retrovirus: human immunodeficiency virus
(HIV)– Hybrid virus- genetic sequences from two separate
monkey SIVs• The disease: acquired immunodeficiency
syndrome (AIDS)• Spectrum of clinical disease associated with HIV
infection• Symptoms directly tied to two things: the level
of virus in the blood and the level of T cells in the blood
Symptoms• Initial infection: vague, mononucleosis-like symptoms
that soon disappear (initial high levels of virus)– Within days, about 50% of the T helper cells with memory
for the virus are destroyed• Period of asymptomatic infection that varies in length
from 2 to 15 years– During this period the number of T cells in the blood is
steadily decreasing– Once T cells reach low enough levels, symptoms of AIDS
ensue• Initial symptoms of AIDS: fatigue, diarrhea, weight
loss, and neurological changes
Other Symptoms as the Disease Progresses
• Opportunistic infections or neoplasms• Severe immune deregulation, hormone
imbalances, metabolic disturbances• Pronounced wasting of body mass• Protracted fever, fatigue, sore throat, and
night sweats• Lesions in the brain, meninges, spinal column,
and peripheral nerves
Figure 20.21
Figure 20.22
Figure 20.23
Figure 20.24
Figure 20.25
Adult T-Cell Leukemia and Hairy-Cell Leukemia
• Leukemia: general name for at least four different malignant diseases of the WBC forming elements originating in the bone marrow
• Some acute, others chronic• Many causes- two of which are thought to be
viral– Adult T-cell leukemia by HTLV-I– Hairy-cell leukemia by HTLV-II
• Signs and symptoms include easy bruising or bleeding, paleness, fatigue, and recurring minor infections