This document discusses various microbial pathogens that can cause cardiovascular and systemic diseases. It describes how bacteria, viruses, protozoa and helminths can infect the bloodstream (septicemia) and spread throughout the body, potentially infecting multiple organ systems. Examples discussed in detail include bacteremia, viral infections like Epstein-Barr virus and cytomegalovirus, and parasitic diseases such as toxoplasmosis, malaria, Chagas disease, schistosomiasis and others. For each pathogen, the document outlines the causative agent, transmission, signs and symptoms, diagnosis and available treatments.

1. Microbial cardiovascular and systemic disease

2. Cardiovascular system and septicemia
 Blood is normally axenic, it contains no microbes
 Septicemia refers to microbial infection of the blood which can
lead to septic shock
 Depending on the type of organism, blood infections are referred
to as:
 *Bacteremia (bacterial septicemia)
 Viremia
 Fungemia
 Parasitemia
Petechiae – sign of bacteremia

3.  Bacteria can release toxins from a site of infection into the blood
causing toxemia
 Exotoxins: i.e., neurotoxins (botulism/tetanus)
 Endotoxins: lipid A of LPS, which can lead to shock
 Severe form of toxemia with septic shock
 Streptococcal toxic-shock-like syndrome (TSLS)
 Streptococcus pyogenes
 From infections of skin/wound
 Staphylococcal toxic shock syndrome (TSS)
 Staphylococcus aureus
 From reproductive tract infections
Cardiovascular system and septicemia

4.  Bacterial septicemia can be associated with
 Infections of the skin/wound
 Surgical wounds
 Urinary tract infections
 Infected teeth
 Improperly sterilized kidney dialysis machines, ….
 Caused by opportunistic or nosocomial bacteria such as
 Escherichia coli, Pseudomonas aeruginosa, Neisseria meningitidis,
Haemophilus influenzae
 Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus
pyogenes
Cardiovascular system and septicemia

5.  Diagnosis of septicemia involves analysis of signs/symptoms
 Culturing bacteria from the blood
 In occult septicemia the exact bacterial cause is hidden
 Treatment involves
 Use of antimicrobial drugs
 Elimination of the initial site of infection (source of
septicemia)
 Intravenous fluid replacement/Antibodies against LPS
 Toxemia caused by Gram negative bacteria
Cardiovascular system and septicemia

6.  Blood and lymph can carry pathogens throughout the body to
cause systemic disease
 Bacterial
 Tularemia
 Plague
 Lyme disease
 Viral
 EBV (Epstein-Barr Virus)
 Cytomegalovirus
 Protozoan
 Toxoplasmosis
 Malaria
 Chaga’s disease
 Helminths
 Schistosomiasis
Microbial systemic disease

7. Bacterial systemic diseases - Tularemia
 Tularemia is a zoonotic disease caused by Francisella tularensis (Gram-
negative coccobacillus)
 Virulence (endotoxin and lipid
capsule – resists phagocytosis)
 Prevalence in animals as
intracellular parasite: from mammals
(rabbit ), to birds, fish, ticks, flies,
mosquitoes, mites
 Multiple mode of transmission
 bite of a tick
 contact with infected animal/animal
slaughter
 contaminated meat or water
 aerosols produced in the laboratory
Mortality rate: ~ 5% of untreated
patients

8. Bacterial systemic diseases - Tularemia
 Highly virulent organism
that causes
 Skin lesion (ulcer) and
swollen pus-filled lymph
nodes near the site of
infection, lymphangitis
 General symptoms may
last for months/years
 malaise, fatigue, joint
stiffness, myalgia
 Diagnosis/treatment
 Serological testing
 Antimicrobials
 Vaccine for people at risk
 Possible use of Francisella as bioterrorism weapon – nationally
notifiable disease (CDC)

9. Plague – Yersinia pestis (Enterobacteriaceae)
 Bubonic plague - bite of infected flea or direct contact with infected
animal
 Pneumonic plague - bacilli spread from the blood to the lungs or are
inhaled (airborne transmission)
 Plague has caused several pandemics
Xenopsylla
cheopis

10. Plague – Yersinia pestis
Bubo: painfully inflamed
lymph node
Darkening of dead tissues
 Plague has been called the “Black Death”
 Bubonic plague is fatal in ~50% of
cases if untreated
 Pneumonic plague is fatal in ~100%
of cases if untreated
 Urban living, rodent and flea
control, antibacterial drugs have
almost eliminated plague
 The disease is considered endemic
in states like California, Arizona,
Nevada
 Potential bioterrorism weapon:
deadly, progresses rapidly, spread
among people

11. Lyme disease (zoonosis)
 Caused by the spirochete
Borrelia burgdorferi
Gram negative
 Bull’s eye rash at the site of
infection
 Untreated patients can develop
severe arthritis

12. Lyme disease is transmitted by a deer tick (Ixodes)
 Deer tick: a 2-years life cycle

13. Lyme disease
 Increase in cases of Lyme
disease
 Diagnosis: detecting
antibodies against
Borrelia
 Antimicrobial drugs can
cure the Lyme disease
(first phase)
 Treatment of later
phases involves anti-
inflammatory drugs

14. Viral systemic diseases – Epstein Barr virus (EBV)
 HHV-4
 Implicated with several diseases, depending on the “relative vigor”
of a host’s cellular immune response

15. EBV and infectious mononucleosis
 EBV is transmitted via saliva, enters the blood and infects B cells,
which become enlarged with lobed nuclei
 Cytotoxic T cells kill infected B cells
 Signs and symptoms: fever, sore throat, fatigue,
enlarged lymph nods and spleen
 Diagnosis: detecting antibody against EBV
 Recover of most patients in few weeks without
specific therapy
 EBV can become latent in the oropharynx: life
long infection which rarely cause disease

16. Cytomegalovirus (CMV) – Herpes virus
 Most people infected with CMV are asymptomatic
 CMV remains in a latent state in various cells
 Complications in
 Immunocompromised patients
 May develop pneumonia, blindness,
 CMV mononucleosis
 Fetuses (may be teratogenic)/newborns
 ~7.5% of neonates infected with CMV
 Bodily secretions carry CMV (saliva, mucous, milk, urine, feces,
semen, vaginal secretions) – it would require a large exchange of
secretions

17. Cytomegalovirus (CMV) – herpes virus
 CMV infections is one of the most common infections in humans
 Transmission usually occurs via
 Sexual intercourse
 Prenatal infection
 Vaginal birth
 Blood transfusion
 Organ transplants
 Diagnosis/Treatment involve
 Owl’s eye appearance of enlarged cells, detection of CMV and
antibodies against CMV
 Interferons, anti CMV immunoglobulins, fomivirsen against
replication of CMV in retinal cells. There is no vaccine against
CMV

18. Protozoan diseases – Toxoplasmosis
 Toxoplasma gondii
 Nucleated cells of wild and
domesticated mammals, birds
 Immunocompromised patients can develop the disease
 Fever, inflammation of several organs, spastic paralysis,
blindness, encephalitis, and death
 Transplacental infections – (first-trimester at higher risk) can cause
spontaneous abortion, mental retardation, blindness, or microcephaly
 Healthy individuals (mostly
asymptomatic)
 Infection normally resolves
without treatment

19.  Humans become infected
when ingesting undercooked
contaminated meat
 Serological detection and
microscopic identification in
tissue samples
 Treatment with a combination
of drugs in AIDS patients,
pregnant women, newborns
Wash fruits and vegetables, eat well
cooked meat!!!
Protozoan diseases – Toxoplasmosis
 Definitive host

20. Malaria is transmitted by
Anopheles mosquito
 Plasmodium species, including
P. falciparum (blackwater
fever)/P. vivax (chronic
malaria)
 Malarial paroxysms: cycles of
fever-chills correlate with
period of erythrocyte lysis
 Anemia and jaundice
(liver/eyes)

21. Protozoan diseases - Malaria
Ring-stage - trophozoites
within red blood cells
 Microscopic examination of blood smears allows diagnosis of
malaria
 Serological tests for specific diagnosis
 Treatment and supportive
measures
 Antimalarial drugs
 Anti-fever medication
 Blood transfusions
 Alternative methods involve
 Limiting contact with mosquitos
carrying Plasmodium
 Malaria vaccines (development
and testing in progress)

22. Protozoan diseases - Malaria
 Malaria is endemic throughout the tropics and subtropics, where
Anopheles breeds
 Mosquito eradication programs eliminated the disease in
Countries like US
 Over 500 million people
are infected
 1-3 million people die
annually

23. Chagas’ disease – American trypanosomiasis
 Caused by Trypanosoma cruzi
 Transmitted with the feces of the bloodsucking “kissing bug”
 Major reservoirs: opossum and armadillos though most mammals,
including humans, can carry the parasite
 ~ 1% of infected humans
develop early stages (general
symptoms)
 Intermediate asymptomatic
(chronic) stage for up to ~ 20
years
 Heart failure during final
symptomatic stage
 Clusters of parasites in the
heart muscle tissue
Trypomastigotes (infective) circulating
in the blood are ingested by the kissing
bug

24. Chagas’ disease – American trypanosomiasis
 The disease is endemic in Central and South America
 Affects 8-15 million people
 Thousands die each
year, including children
 Early stages can be treated
but not late stages
 No vaccine exists for
Chagas’s disease
 Prevention involves measures that protect against bugs: mud
replaced with concrete/brick, insecticides …..

25. Schistosomiasis is caused by blood flukes
 Genus
Schistosoma
 The larval stage
cercaria burrows
into the skin
 Feeding on blood,
matures, mates, and
releases eggs
 Eggs lodge in
tissues causing
damage to several
organs

26.  Treatment/control: drugs that kill the
worm in the body, sewage treatment,
and snail suppression
Egg of Schistosoma mansoni
 Diagnosis: identification of eggs -
shape of the egg and location of the
spines - in stool or urine samples
 WHO (World Health Organization) estimates that over 250 million
people are infected worldwide – Asia, Africa, South America
Schistosomiasis is caused by blood flukes
Scarlike tissue surrounds the egg