Infectious Diseases of the Cardiovascular System and Lymphatic System

What are the main components of the cardiovascular system?

Blood vessels + heart (closed circulatory system)

What does the cardiovascular system do?

Delivers oxygen/nutrients and removes CO₂ + waste

What are the components of the lymphatic system?

Lymph vessels, lymph nodes, spleen

What is the function of the lymphatic system?

Returns fluid to blood + provides immune cells

Why are bloodstream infections dangerous?

Because microbes can spread everywhere → systemic infection

What immune cells are found in blood?

5,000–10,000 WBCs per µL

What do lymphocytes do?

Adaptive immunity

What do phagocytes do?

Engulf pathogens (innate + adaptive roles)

Do the cardiovascular and lymphatic systems normally have microbiota?

No — they are “closed systems”

Are they completely sterile?

Mostly, but some studies suggest tiny amounts may exist

What is viremia?

Viruses in the blood

What is bacteremia?

Bacteria in the blood

What is fungemia?

Fungi in the blood

What is septicemia (sepsis)?

Bacteria actively growing in the blood

What is septic shock?

Severe immune response → low blood pressure → life-threatening

What causes malaria?

Plasmodium species (parasite)

How is malaria transmitted?

Mosquito (vector)

What are the 3 life cycle stages of malaria?

• Sporogony → mosquito

• Exo-erythrocytic → liver

• Erythrocytic → blood

Which malaria species is most dangerous?

Plasmodium falciparum

Why is P. falciparum so virulent?

• High transmission

• Drug resistance

• Destroys many RBCs

What are common malaria symptoms?

• Cyclic fever

• Fatigue

• Nausea

• RBC rupture

What serious complication can malaria cause?

Cerebral malaria (brain oxygen loss → coma/death)

How is malaria diagnosed?

Blood smear, PCR, serology

How is malaria prevented?

Mosquito nets, repellents, prophylactic drugs, vaccines

How is malaria treated?

Antimalarials (quinine, chloroquine—resistance issue)

What causes HIV?

Human immunodeficiency virus (retrovirus)

What cells does HIV attack?

CD4+ T helper cells (also macrophages, B cells)

Which cells are monitored for HIV progression?

CD4 T cells

How is HIV transmitted?

Sexual contact, blood, birth, breastfeeding

What are early HIV symptoms?

Fatigue, weight loss, diarrhea, infections

When is HIV diagnosed as AIDS?

CD4 < 200 OR AIDS-defining illness

How is HIV diagnosed?

Antibody tests, PCR

How is HIV treated?

Antiretroviral therapy (ART)

How is HIV prevented?

Safe sex, avoid IV drugs, PrEP

What is endocarditis?

Infection/inflammation of inner heart lining

Main cause of acute endocarditis?

Staphylococcus aureus

How is acute endocarditis transmitted?

Direct entry (IV drugs, surgery)

What happens to heart valves?

Vegetations form → can break off → emboli

How can you diagnose acute endocarditis?

Blood culture

What is the treatment of acute endocarditis?

Antibiotics (vancomycin) + surgery

What causes subacute endocarditis?

Oral bacteria (Streptococcus spp.)

Who is at risk for subacute endocarditis?

People with damaged valves

How is subacute endocarditis transmitted?

Dental work, brushing teeth

Symptoms of a subacute endocarditis

Mild fever, fatigue, anemia, enlarged spleen

Prevention of subacute endocarditis

Prophylactic antibiotics before dental work

What is septicemia?

Microbes multiplying in the bloodstream

Common symptoms of septicemia?

Fever, chills, low BP, rapid breathing

Why does BP drop in septicemia?

Massive inflammatory response

Common causes of septicemia

Gram + and Gram – bacteria (MRSA common)

How can you diagnose septicemia

Blood culture

What is a treatment for septicemia

Broad-spectrum antibiotics → adjust later

What is a hemorrhagic fever disease?

Fever + bleeding (capillary damage)

What causes hemorrhagic fevers?

RNA viruses

What is a non-hemorrhagic fever?

Fever WITHOUT bleeding

Main difference of hemorrhagic vs. non-hemorrhagic?

Hemorrhage vs no hemorrhage

Yellow fever, dengue, chikungunya — transmission?

Mosquito

Ebola & Marburg — transmission?

Direct contact (body fluids, bats reservoir)

Lassa fever — transmission?

Rodent contact

General symptoms of hemorrhagic fevers?

Fever + internal bleeding

What are the 7 diseases?

• Brucellosis

• Q fever

• Cat-scratch disease

• Ehrlichiosis

• Anaplasmosis

• Babesiosis

• Rocky Mountain spotted fever

What causes brucellosis?

Brucella (livestock)

Q fever cause?

Coxiella burnetii (animal birth products)

Cat scratch disease cause?

Bartonella henselae

Ehrlichiosis & anaplasmosis transmission?

Tick bites

Babesiosis cause?

Protozoan (Babesia)

RMSF cause?

Rickettsia rickettsii

Classic RMSF symptom?

Spotted rash starting on wrists/ankles

What is seen in blood smear of babesiosis?

Maltese cross formation inside RBCs

Cause of a plague?

Yersinia pestis

How is the plague transmitted?

Fleas (usually rodents)

What is the symptom of the plague?

Buboes (swollen lymph nodes)

Cause of tularemia

Francisella tularensis

How is tularemia transmitted?

Tick, animals, aerosols

What are causes of lyme disease?

Borrelia burgdorferi

How is lyme disease transmitted

Tick bite

What are classic sign’s of lyme disease?

Bull’s-eye rash

What is the cause of mononucleosis?

Epstein-Barr virus

How is mononucleosis transmitted?

Saliva (“kissing disease”)

What is the key symptom of mononucleosis?

Extreme fatigue + swollen lymph nodes

Causes of Chagas disease?

Trypanosoma cruzi

How is Chagas transmitted?

Kissing bug

Key sign of Chagas

Romana’s sign (eye swelling)

Causes of Anthrax

Bacillus anthracis

How is anthrax transmitted?

Spores (air, skin, ingestion)

What are the main forms of anthrax?

Cutaneous, pulmonary, GI