Chapter 18 Infectious Disease Affecting the Cardiovascular and Lymphatic System

malaria

caused by plasmodium parasite, transmitted by the bite of infected mosquitoes

primarily found in tropical countries

malaria symptoms

high fevers

shaking chills

flu-like symptoms

protozoan cyst

protozoa exists in an active, trophozoite form

during poor conditions, protozoa can produce this 

when conditions improve, trophozoite exits through excystment

life cycle of parasite

1. mosquito transmits sporozoita

2. Sporozoite travels through the blood vessels to liver cells

3. In the liver, sporozoite reproduces asexually —> thousands of merozoites form

4. Merozoites infect red blood cells, then develop into ring forms, tropozoites, and schizonts

5. Other meroziotes develop into precursors of male and female gametes

6. when mosquito bites infected person, gametocytes are taken up and mature in their gut. 

7. male and female gametocytes fuse and form an ookinete

8. ookinetes develop into new sporozoites that migrate to the insect’s salivary glands

treatment of malaria

depends on…

1. many factors including disease severity

2. the species of malaria parasite

3. part of the world in which the infection was acquired

(last two determine probability that the organism is resistant to certain antimalarial drugs)

biologic advantage (genetic factors)

persons who have the sickle cell trait (heterozygotes for the abnormal hemoglobin gene HbS) are relatively protected against P. falciparum malaria and thus enjoy a __________

people with homozygous sickle cell anemia are also protected but they rarely live long enough

malaria diagnosis

microscopic examination is the “gold standard” for lab confirmation

rapid diagnostic test (RDT) for specific antigens in a person’s blood

indirect fluorescent antibody test

treatment of malaria

first pharmaceutical used —> quinine

artemisinin-based combination therapies (ACTs) are most effective anti medicines

prevention of malaria

1. using bed nets sprayed with insecticide

2. eliminating standing water

3. taking prophylactic drugs

4. decreasing the mosquito population

Chagas disease

inflammatory, infectious disease caused by the parasite Trypanosoma cruzican can infect anyone

chagas symptoms

if left untreated, can cause serious heart and digestive problems

cardiac and gastrointestinal complications

Yersinia pestis + plague

nonenteric

tiny, gram negative rod, unusual bipolar staining and capsules

virulence factors —> capsular and envelope proteins that protect against phagocytosis and foster intracellular growth

yersinia pestis

developed through contact with wild or domestic animals or infected humans

mammal and flea vectors

types of yersinia pestis

bubonic

septicemic

pneumonic

bubonic yersinia pestis/plague

bacillus multiples in flea bite, enters lymph, causes necrosis and swelling called a bubo

septicemic yersinia pestis/black plague

progression to massive bacterial growth; causes hemorrhage and purpura (darkening of the skin)

pneumonic yersinia pests/plague

infection localized to lungs, highly contagious; fatal without treatment

bubonic or septicemic plague transmission

flea bites: most often transmitted by the bite of an infected flea. dogs and cats bring it into homes

septicemic plague transmission

contact with contaminated fluid or tissue

pneumonic plague transmission

infectious droplets

yersinia pestis treatment and prevention

diagnosis: depends on history, symptoms, and lab findings from aspiration of buboes

streptomycin has a 90-95% survival rate

vaccine available, quarantine and control of rodent population in human habitats

tularemia

zoonotic disease of mammals’ endemic to the northern hemisphere, particularly rabbits

transmitted by contact with infected animals or bites by vectors

10% death rate in systemic and pulmonic forms (treatable with gentamicin or streptomycin)

tularemia symptoms

headache

backache

fever

chills

weakness

Francisella tularensis

bacteria that causes tularemia

ulcerative skin lesions, swollen lymph glands, conjunctival inflammation, sore throat, intestinal disruption

intracellular persistence can lead to relapse

no vaccine currently available

often considered one of the most infectious of all bacteria

potential bioterrorism agent

most infectious pathogenic bacteria and 10 bacteria can cause disease

infection occurs through a variety of entry sites (inhalation, skin or mucous membranes, ingestion, the bite of a tick or fly vector)

francisella tularensis

bacteria that causes rabbit fever

yersinia pestis

bacteria that causes bubonic plague

types of heart infections

occur from bacteria, viruses and fungi

heart muscle (myocardium)

heart valves

inner lining (endocardium)

outer membrane or sac (pericardium)

heart infections

type of infection that occurs when people:

are older than 65 years of age

have had heart surgery

use injected recreational drugs

endocarditis

80% of cases are caused by streptococci and staphylococci

HIV infection and AIDS

caused by human immunodeficiency virus

leads to AIDS —> most advanced stage of this infection

spreads through contact with the blood, body fluids, and shared needles

AIDS

if HIV is not treated, it can cause acquired immunodeficiency syndrome

HIV symptoms

fever

sore throat

swollen lymph nodes

rash

muscle aches

night sweats

mouth ulcers 

chills 

fatigue

HIV life cycle

1. binding (attachment)

2. fusion

3. reverse transcription

4. integration

5. replication

6. assembly

7. budding

HIV integration

inside the CD4 cell nucleus, HIV releases integrase. HIV uses integrase to insert its viral DNA into the DNA of the CD4 cell

HIV reverse transcription

inside the CD4 cell, HIV releases and uses reverse transcriptase to convert its genetic material (HIV RNA) into HIV DNA. the conversion of HIV RNA TO HIV DNA allows HIV to enter the CD4 cell nucleus and combine with the cel’’s genetic material (cell DNA)

HIV fusion

HIV envelope and the CD4 cell membrane fuse, which allows HIV to enter to CD4 cell

HIV binding

HIV binds to receptors on surface of CD4 cell

HIV replication

once integrated into the CD4 cell DNA, HIV begins to use the machinery of the CD4 cell to make long chains of HIV proteins. The protein chains are the building blocks for more HIV.

HIV assembly

new HIV proteins and HIV RNA move to the surface of the cell assemble into immature (noninfectious) HIV

HIV budding

newly formed immature (noninfectious) HIV pushes itself out of the host CD4 cell. The new HIV releases protease that breaks up the long protein chains in the immature virus, creating mature (infectious) virus

key points of HIV life cycle

1. HIV attacks and destroys the CD4 cells of the immune system

2. HIV uses the machinery of the CD4 cells to multiply and spread throughout the body.

3. HIV medicines protect the immune system by blocking HIV at different stages of the HIV life cycle

4. Antiretroviral therapy (ART) is the use of a combination of HIV medicines to treat HIV infection. People on ART take a combination of HIV medications from at least two different HIV drug classes every day.

5. ART is very effective at preventing HI from multiplying

HIV treatment

ART (antiretroviral therapy)

ART (antiretroviral therapy)

use of HIV medicines to treat HIV infection

HIV treatment regimen: people on this take a combination of HIB medicines every day

recommended for everyone who has HIV

cannot cure HIV infection, but HIV medicines help people with HIV live longer, healthier lives

HIV medicines can also reduce the risk of HIV transmission

three stages of HIV

1. acute

2. chronic

3. acquired immunodeficiency syndrome (AIDS)

lyme disease

caused by the tick-borne spirochete bacterium Borrelia Burgdorferi

transmitted by ticks

multisystem inflammatory disease with neurologic and cardiac problems

Borrelia Burgdorferi

bacteria that causes lyme disease

lyme disease symptoms

rash

headache

fever

chills

lyme carditis

occurs when lyme disease bacteria enter the tissues of the heart

can interfere with normal movement of electrical signals from the heart’s upper to lower chambers, a process that coordinates the beating of the heart

occurs in 1 out of every 100 lyme disease cases 

spirochete

borrelia is a ______