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 subacutethe 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

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J43 Insert Figure 20.26 HereJennifer, 2/25/2008