Micro U2 L1 pt 2.

Question 1

How does transmission of most parasitic infections spread?

Answer 1

mosquitos, ticks, specific flies, other arthropods

Question 2

What is human to most parasitic infections?

Answer 2

intermediate host. sexual reproduction occurs in vector associated with transmission of agent

Question 3

Plasmodium

Answer 3

protozoan parasite - malaria

Question 4

Which area of the world is most affected by malaria and why?

Answer 4

africa - very efficient mosquito (anophele gambiae complex); predominant parasite species is plasmodium falciparum; warm weather = year round

Question 5

What transmits malaria?

Answer 5

anopheles mosquitos - usually by female mosquitos

Question 6

What are the four parasite species that cause malaria in humans?

Answer 6

plamodium falciparum, vivax, malariae, ovale

Question 7

Plasmodium falciparum

Answer 7

most fatal outcomes - sub saharan africa, SE asia, S america

Question 8

Plasmodium vivax

Answer 8

most common, seen in US - NOT seen in sub saharan africa

Question 9

Plasmodium malariae

Answer 9

all malarious areas, but spotty

Question 10

Plasmodium ovale

Answer 10

tropical areas - africa; SE asia, S america

Question 11

What are the clinical symptoms of malaria due to?

Answer 11

schizont rupture and destruction of erythrocytes

Question 12

What are the prodromal symptoms of malaria?

Answer 12

fever, chills, headaches, diaphoresis

Question 13

What are malarial paroxysms?

Answer 13

febrile attacks following the prodromal symptoms - exhibit periodicities (24 hrs for vivax, ovale, falciparum and 72 hr for malariae)

Question 14

What are natural protections against malaria?

Answer 14

1. hg C, S (sickle cell) 2. Duffy antigen - lack this = low incidence 3. thalassemia

Question 15

What are the stages of the malaria paroxysm?

Answer 15

1. cold stage (lysis of RBC) - intense cold feeling, shivering, 15-20 min 2. hot stage - due to circulating and innate immune response - intense heat, dry burning skin, throbbing headache, 2-6 hr 3. sweating stage due to infection of additional erythrocytes and immune system shutting off - profuse sweating, declining temp, exhausted and weak, 2-4 hr

Question 16

What are the major complications of severe malaria?

Answer 16

cerebral malaria, pulmonary edema, acute renal failure, severe anemia, bleeding

Question 17

What are the most common metabolic complications of malaria?

Answer 17

acidosis and hypoglycemia

Question 18

PfEMP-1 antigen

Answer 18

on 100% of RBCs

Question 19

What causes stable stationary adherence of the parasitized RBCs?

Answer 19

CD36 and chondroitin sulphate A (CSA) - surface of P falciparum trophozoite and schizont infected RBCs is covered with knob-like excrescences made up of the PfEMP-1 antigen

Question 20

How does p falciparum modify the surface of RBCs so that asexual parasites and gametocytes can adhere to the endothelium and asexual parasites can adhere to the placenta?

Answer 20

knob-like excresences made up of PfEMP-1 antigen

Question 21

Cerebral malaria

Answer 21

most severe neurological complication of infection with plasmodium falciparum - breakdown of BBB due to cytoadherence of infected RBCs and vascular sequestration of infected erythrocytes

Question 22

Placental malaria

Answer 22

accumulation of parasitized erythrocytes and monocytes in the placenta, direct adverse birth outcomes

Question 23

Malaria relapse

Answer 23

reactivation of infection via hypozoites released from the liver (with vivid and ovale only) - second drug should be given with these types to help prevent relapses

Question 24

Malaria recrudescence

Answer 24

parasitemia falls below detectable levels and later increases to detectible level = re-attack of malaria due to surviving malaria parasites in RBCs. Due to: 1. incomplete or inadequate treatment 2. antigenic variation 3. multiple infections

Question 25

Malaria Treatment

Answer 25

chloroquine (RBC stage) and paraquinine (liver stage for ovale and vivax)

Question 26

American Trypanosomiasis

Answer 26

Chagas disease - chronic, systemic parasitic infection by trypanosoma cruzi - NOT intracellular

Question 27

Who does Chagas disease affect?

Answer 27

Latin america

Question 28

What do people with chagas disease develop later on?

Answer 28

cardiomyopathy, digestive megasyndromes (esophagus and colon esp), or both

Question 29

What transmits Cagas disease to humans?

Answer 29

large, bloodsucking reduviid bugs (tick like) - also by blood transfusion and mother to infant

Question 30

What is the method of transmission from reduviid bug to human?

Answer 30

bug takes blood meal and releases trypomastigotes in feces near bite wound - enters through wound or intact mucosal membranes (conjunctiva)

Question 31

What is the classic sign for Chagas infection?

Answer 31

Romana’s sign - swelling of the eyelids near the bite or where the feces was rubbed into eye

Question 32

What are the clinical manifestations of Chagas disease?

Answer 32

initial infection - acute infection 4-8 weeks, chronic for life

Question 33

Acute phase of Chagas disease

Answer 33

asymptomatic - might have self-limiting febrile illness - resolve spontaneously in about 90% of infected individuals

Question 34

Chronic chagas disease

Answer 34

cardiac, diestive, cardidigestive disease usually 10-30 years after initial infection

Question 35

Chagas heart disease

Answer 35

low intensity, slowly progressive that leads to impairment of contractile function and dilatation of all four chambers. most frequent and serious manifestation of chagas

Question 36

What are the causes of death in chagas heart disease?

Answer 36

sudden death, refractory heart failure, thromboembolism

Question 37

Gastrointestinal dysfunction

Answer 37

mainly megaesophagous, megacolon, or both. megacolon = end segments causing abdominal distention, large bowl obstruction, prolonged obstipation. megaesophagus = dysphagia with odynophagia, epigastric pain, regurgitation , ptyalism (excessive saliva), malnutrition (severe)

Question 38

Diagnosis of chagas

Answer 38

acute: microscopic detection of trypomastigotes in blood. chronic: presence of IgG antibodies against T cruz antigens

Question 39

Toxoplasmosis

Answer 39

T gondii - coccidian parasite- humans intermediate host so uncommonly cause disease in humans

Question 40

When does toxoplasmosis cause disease?

Answer 40

usually fetuses and immunologically impaired individuals - typically by food borne transmission (undercooked meat) or CATS MEOW (litter box)

Question 41

Congenital Toxoplasmosis

Answer 41

Classic triad: chorioretinitis, hydrocephalus, intracranial calcifications. Transmission risk greatest during 3rd trimester, but earlier the infection = more severe symptoms

Question 42

Pathogenesis of toxoplasmosis in healthy people

Answer 42

often no symptoms - if there are = flu-like - also most common cause of posterior uveitis - parasite remains in body in inactive state

Question 43

Toxoplasma ocular infection

Answer 43

results from congenital infection or infection after birth. symptoms: eye pain, photophobia, tearing of the eyes, blurred vision

Question 44

How does reactivation of ocular infection appear on exam?

Answer 44

white fluffy cottony lesions

Question 45

What is the diagnostic method to determine infection with toxoplasma?

Answer 45

toxoplasma specific antibodies

Question 46

Lesihmania

Answer 46

found in desert - affect military - usually cause skin lesions and liver shit