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Flashcards in Chapter 21 Deck (14)
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Endocarditis (42)

Signs & Symptoms:
-Inflammation of endocardium; fever, fatigue, malaise, and difficulty breathing; Tachycardia may be detected

-Viridans Streptococci causes most cases; normal microbiota are usually responsible

Pathogenesis and Epidimiology:
-Patients usually have obvious source of infection; patients w/abnormal heart have increased risk ; Embolus can block blood vessels in other organs

Diagnosis, Treatment, & Prevention
-Vegetations visualized by echocardiogram; diagnosis is based on symptoms; treated w/intravenous antibacterial drugs; prophylactic antiobiotics for high-risk patients when needed


Brucellosis (43)

Signs & Symptoms:
-Fluctuation Fever that spikes every afternoon (24 hrs)

Pathogen and Virulence Factors:
-Caused by Brucella Melitensis Strains; endotoxin causes some of the signs and symptoms

Pathogenesis & Epidemiology
-Consumption of contaminated dairy products; contact w/animal blood, urine, or placentas; usually requires no treatment


Tularemia (44)

Signs & Symptoms:
-Skin lesions & swollen lymph nodes at infection site; ascending lymphangitis

Pathogen and Virulence Factors
- Caused by Francisella tularensis; diverse host range includes mammals, birds, fish, ticks, and insects, rabbits; can survive within infected cells; endotoxin causes many signs & symptoms

Pathogenesis & Epidemiology
-As few as 10 cells can cause infection and resulting disease; transmitted via bite of infected tick or contact with infected animal; small size of bacteria allows entry through seemingly unbroken skin; individuals in contact with dead animals at highest risk


Plague (45)

Signs & Symptoms:
-Bubonic plague: characterized by enlarged lymph nodes called buboes
-Pneumonic Plague (most dangerous): Occurs when the bacterium spreads to the lungs; difficulty breathing can develop rapidly

Pathogen and virulence factors
-Caused by Yersinia Pestis; Adhesins, Type III secretion systems, capsules, and antiphagocytic proteins

Pathogenesis & Epidimiology
-Transmitted by contact w/infected animal flea feces*; Bubonic plague fatal in 50% of cases if untreated; Penumonic plague fatal in 100% of cases if untreated

Diagnosis, Treatment, & Prevention
-Must be diagnosed & treated immediately; treated with various antimicrobial drugs; Prevented with rodent and flea control and good hygiene


LymeDisease (46)

Signs & Symptoms
-3 Phases in untreated patients; Bull's eye rash at infection site; Neurological symptoms & Severe arthritis

Pathogen & Virulence factors
-Caused by the spirochete Borrelia burgdorferi; a tick bome zoonosis( deer tick lxodes is vector); *use manganese instead of iron circumvents host defense; avoids immune detection by altering membrane protein

-One of the most reported vector-borne diseases in the U.S.; 3 events contributed to an increase in Lyme disease; Movement of human population into woodland areas; protection of the deer population ; coyotes have displaced the foxes that help control the mouse population

Diagnosis, Treatment, & Prevention
-Diagnosis is based on the signs & symptoms of the disease; bacterium is rarely detected in the blood; antimicrobial drugs are used in the early phases; treatment of later phases is difficult; symptoms often caused by the immune system; prevented with repellents containing DEET & with protective clothing


Infectious Mononucleosis (47)

Signs & Symptoms:
-Severe sore throat & fever initially; followed by swollen lymph nodes, fatigue, appetite loss, and a skin rash

Pathogen & Virulence Factors
-Epstein-Barr Virus (EBV or HHV-4) is the causative agent; EBV establishes latent infection in host; EBV is implicated in a number of other diseases

Pathogenesis & Epidemiology
-Transmission occurs via saliva; EBV infects B lymphocytes; majority of adults have antibodies against EBV

Diagnosis, Treatement, & Prevention
-Diagnosed by presence of large, lobed B lymphocytes and neutropenia; treatment focuses on relieving symptoms; Prevention is difficult since EBV occurence is widespread


Cytomegalovirus (48)

Signs & Symptoms:
-Asymptomatic in most cases; Complications in neonates and the immunocompromised

Pathogen & Virulence Factors
-Caused by Cytomegalovirus

Pathogenesis & Epidemiology
-May be teratogenic- this causes birth defects;Transmit by direct contact with bodily fluids or transplacentally; one of the most common infections of humans

Diagnosis, Treatment, & Prevention
-Diagnosed by identifying enlarged cells with inclusions; Fomiversen is administered for eye infections; no vaccine is available


Yellow Fever (49)

Signs & Symptoms:
-1st Stage is fever, headache, muscle aches; 2nd stage is period of remission; 3rd Stage is delirium, seizures, coma, hemorrhaging

Pathogen & Virulence Factors
-Caused by yellow fever virus

Pathogenesis & Epidemiology
-Transmitted via the bite of an infected Aedes Mosquito; Virus travels to the liver where it replicates; Yellow fever cases occur today in South America and Africa

Diagnosis, Treatment, & Prevention
-Diagnosed by detecting viral antigens in the blood; treatment is supportive; VACCINE IS AVAILABLE


Dengue Fever & Dengue Hemorrhagic Fever (50)

Signs & Symptoms
-Dengue Fever (Breakbone fever): 1st phase is fever, edema, head & muscle pain; 2nd phase is the return of fever and red rash
-Dengue Hemorrhagic Fever; internal bleeding, shock, and possibly death

Pathogens and Virulence Factors
-Caused by Four Strains of dengue Viruses; Aedes mosquitos are the vector.

Pathogenesis & Epidemiology
-Dengue fever is usually a mild disease; Dengue hemorrhagic fever is more severe & can be fatal; Distribution of dengue diseases has expanded

Diagnosis, treatment, & Prevention
-Diagnosis is based on signs & symptoms in people who have traveled to endemic regions; no specific treatment is available. Prevention requires control of mosquitoes.


African Viral Hemorrhagic Fever (51)

Signs & Symptoms
-Fever & Fatigue; Minor petechiae progress to severe internal hemorrhaging

Pathogens & Virulence
-Caused by Ebolavirus or Marburgvirus

Pathogenesis & Epidemiology
-Malfunctioning blood clotting causes hemorrhaging; Occurs primarily in Africa; Transmitted via contact with bodily fluids of infected individual

Diagnosis, Treatment, & Prevention
-Diagnosis is based on characteristic symptoms & presence of virus in the blood; Treatment involves fluid & electrolyte replacement; vaccines are being studied for their effectiveness in humans


Malaria (52)

Signs & Symptoms
-Associated w/parasite's life in erythrocytes; fever, chills, diarrhea, headache; Anemia, weakness, & fatigue gradually occur

Pathogen & Pathogenesis
-At least 4 Plasmodium Species cause Malaria; P. falciparum causes the most severe malaria; disease severity depends on the species; children are particularly vulnerable to infection; Certain genetic traits increase resistance to Malaria

-Endemic throughout tropics and subtropics; Malaria causes more then 1 million deaths annualy

Diagnosis, treatment, & Prevention
-Diagnosis made by identifying Plasmodium in blood; treated w/various antimalarial drugs; some Plasmodium strains are resistant to antimalarial drugs; Prevention requires control of mosquitoes


Toxoplasmosis (53)

Signs & Symptoms
-Majority of cases have no symptoms; Symptoms in individuals w/poor immunity; Fetal Infections can cause numerous conditions, including spontaneous abortion of stillbirth

Pathogen & Virulence Factors
-Toxoplasma gondii is the causative agent; Cats are the definitive host; Toxoplasma infects and lives in many cell types

Pathogenesis & Epidemiology
-Consumed in undercooked meat containing the parasite; transmission across the placenta can also occur; Specific mechanism of disease is not yet known

Diagnosis, treatment, & Prevention
-Diagnosed mainly by detection of organisms in tissues; Treatment needed only in AIDS patients, pregnant women, and newborns; Prevention is difficult because T. gondii has numerous hosts


Chagas' Disease (54)

Signs & Symptoms
-Chronic manifestations can occur years after infection; Swelling at infection site & nonspecific symptoms

Pathogen & Virulence Factors
-Cause by Trypanosoma cruzi; Endemic throughout Central & South America; Most mammals can harbor T. Cruzi; T. Cruzi evades the immune system in several ways

Pathogenesis & Epidemiology
-Transmitted through the bite of infected Triatoma or transfusion with infected blood; Progresses through 4 stages over several months

Diagnosis, Treatment, & Prevention
-Diagnosed by microscopic identification of T. Cruzi or xenodiagnosis; most patients show no early symptoms, and late stages of the disease cannot be treated; Prevention involves avoidance of Triatoma bugs


Schistosomiasis (55)

Signs & Symptoms
-Swimmer's itch may occur at infection site; eggs deposited throughout body can cause other symptoms

Pathogens & Virulence Factors
-Caused by 3 species of Schistosoma

Pathogenesis & Epidemiology
-Humans are principal host for most Schistosoma species and is not found in the U.S.

Diagnosis, Treatment, & Prevention
-Diagnosed by identifying eggs in stool or urine sample; treated with praziquantel; prevention requires avoiding potentially contaminated water