Microbiology - Vossler - Parasitic Infections of the Blood Flashcards
The main type of malaria in (sub-saharan) Africa is caused by:
plasmodium falciparum, the most lethal strain
_____ is the most common malaria strain worldwide and is the cause of a large percentage of cases in the United States.
P. vivax is the most common strain worldwide and is the cause of a large percentage of cases in the United States.
P. falciparum is next most common.
Less common are P. malariae and P. ovale
T/F: Untreated infected patients eventually develop curative immunity against the parasitizing strain or malaria
True
_______ is the erythrocyte receptor for P. vivax merozoite invasion.
Duffy antigen is the erythrocyte receptor for P. vivax merozoite invasion.
Absence of the Duffy antigen (West Africans) is protective against P. vivax.
The anemia in malaria is due to:
The anemia in malaria is due to the rupture of parasitized erythrocytes, removal of parasitized and unparasitized erythrocytes by the spleen, capillary sequestration and bone marrow dyserythropoiesis
Name 3 symptoms of malaria.
fever, chills, headache, sweats, Fatigue, nausea and vomiting, splenomegaly, cough, back pain, muscle pain
What is the cold stage of the malaria paroxysm?
The malaria paroxysm –> the rupturing of RBCs every 48-72 hours
“feeling of intense cold
vigorous shivering
lasts 15-60 minutes”
What is the hot stage of the malaria paroxysm?
Follows cold stage: "intense heat dry burning skin throbbing headache lasts 2-6 hours"
What is the sweating stage of the malaria paroxysm?
After the hot stage
Full paroxysm may last 4-8 hours and then resolve
“profuse sweating
declining temperature
exhausted and weak →sleep
lasts 2-4 hours”
The cyclic pattern of malaria symptoms is due to:
The cyclic pattern of malaria symptoms is due to the life cycle of malaria parasites camera as they develop, reproduce, and are released from the red blood cells and liver cells in the human body. This cycle of symptoms is also one of the major indicators of the species malaria causing infection.
Recrudescence is:
Malaria
Recrudescence is used to describe the situation in which parasitemia falls below detectable levels and then later increases to a detectible parasitemia.
Relapse is:
Malaria
Reactivation of the infection via hypnozoites released from the liver.
P. vivax and P. ovale have liver stages can remain in the body for up to 30 years w/o symptoms.
Hepatocytes rupture
Relapse is NOT seen in P. falciparum and P. malariae.
The ability to sequester in the deep venous microvasculature characterizes what malaria strain?
An important feature of the pathogenesis of P. falciparum is its ability to sequester in the deep venous microvasculature.
The most significant pulmonary manifestation directly attributable to P. falciparum is:
Noncardiogenic pulmonary edema
Hypoglycemia in malaria can cause coma and convulsions and contributes substantially to the morbidity and mortality associated with _______.
cerebral malaria
The classic histopathological finding of fatal cerebral malaria is the intense sequestration of parasites in the cerebral microvasculature often accompanied by ring hemorrhages, perivascular leukocyte infiltrates, and immunohistochemical evidence for endothelial cell activation.
Sequestration of parasites is thought to stimulate the local production of inflammatory cytokines and mediators.
Name the four major sequelae associated with P. Falciparum infection:
Anemia
Metabolic Acidosis
Pulmonary edema and respiratory distress
Hypoglycemia
P. falciparum erythrocyte membrane protein-1 (PfEMP-1) is central to malaria pathogenesis, specifically P. falciparum.
_____ is the major receptor for PfEMP-1
CD-36
T/F: Malaria is intracellular.
True
The primary factor for malaria resurgence seems to be:
drug-resistant strains popping up
Malaria is exclusively transmitted through bites from the ____ mosquito.
Anopheles
Chagas disease is also known as:
American Trypanosomiasis
caused by the protozoan Trypanosoma cruzi
What is the vector for Trypanosoma cruzi?
The reduviid bug in the Americas;
the tse tse fly in Africa
T/F: Vertical transmission of Trypanosoma cruzi is possible.
True
What is Romana’s sign?
Swelling of the eyelids near the reduviid bute where the feces was rubbed into the eye
The initial phase of Chagas disease lasts:
4-8 weeks, acute
Chronic can be for life in 30-40% of patients
What is Chagas heart disease?
Low intensity, slowly progressive myocarditis
20-30% of individuals
sudden death common
Megacolon describes what chronic disease?
A manifestation of chronic Chagas disease
Can also have megaesophagus
How is the diagnosis of Chagas made?
Acute infection - detection of trypomastigotes in the blood
chronic - need two IgG readings (ie ELISA and indirect immunoflourescence)
How is leishmaniasis transmitted?
Sand fly
The three types of leishmaniasis are:
Cutaneous
Visceral
Mucocutaneous
________ is considered to be a leading cause of death attributed to foodborne illness in the United States.
Toxoplasmosis is considered to be a leading cause of death attributed to foodborne illness in the United States.
What are the methods of toxoplasma gondii transmission?
People become infected through the accidental consumption of feline fecal material,
through food or water with fecal contamination,
through the consumption of undercooked meat containing infective cysts,
through transplantation, or
transplacentally from mother to fetus.
The classic triad of signs suggestive of congenital toxoplasmosis includes
chorioretinitis, hydrocephalus, and intracranial calcifications.
highest risk of transmission is during 3rd trimester
_______ is the leading cause of focal central nervous system (CNS) disease in AIDS.
Toxoplasmosis is the leading cause of focal central nervous system (CNS) disease in AIDS.
Humans are what kind of host for T. gondii?
Intermediate
In the human eye, toxoplasma infection causes:
a necrotizing chorioretinitis, with varying (and recurring) degrees of posterior and anterior uveitis
