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118 Cards in this Set
- Front
- Back
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What kind of life cycle do Plasmodium have?
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heteroxenous life cycle involving a vertebrate host and an arthropod vector
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What type of vector transmits Plasmodium?
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anopheline mosquitoes
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Describe the generalized life cycle of plasmodium
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parasite is injectedby mosquito undergoes a round of merogony in the liver followed by multiple rounds of merogony in the erythrocytes. Gametogony begins in erythrocytes of the host and is completed within the mosquito where sporogony takes place.
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What is the prepatent period for falciparum?
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6-9 days
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What is the prepatent period for vivax?
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8-12 days
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What is the prepatent period for ovale?
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10-14
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What is the prepatent period for malariae?
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15-18
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What is the incubation period for falciparum?
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7-14
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What is the incubation period for vivax?
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12-17
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What is the incubation period for ovale?
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16-18
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What is the incubation period for malariae?
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18-40
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What indicates the prepatent period in Plasmodium?
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time between sporozoite inoculation and appearance in the blood
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What is meant by the incubation period for Plasmodium?
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period btw inoculation of sporozoites and onset of symptoms
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Which Plasmodium spp can enter a hypnozoite?
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Ovale and vivax
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What does recrudescence mean?
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parasitemia drops below detectable levels then resurges
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How long after initial infection can there be a ovale relapse?
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less than one year
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How long after initial infection can there be a vivax relapse?
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several years
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What is the by product of hemoglobin?
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hemozon, malaria pigment
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Which stage of falciparum adhere to endothelium?
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schizont and trophozoite
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What is an alternative to schizongony in Plasmodium?
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gametocyte production
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Where does gametogenesis (formation of micro- macro gametes) happen?
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in the mosquito
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What induces exflagellation in Plasmodium?
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exposure to air
decrease in temp (2-3C) increase to pH above 8 Xanthurenic Acid (mosquito metabolite) |
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What is the average parasitemia for vivax?
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20 000
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What is the ave parasitemia for ovale?
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9000
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what is the ave parasitemia for malariae?
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6000
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what is the ave parasitemia for falciparum?
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50 000-500 000
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What is the maximum parasitemia for Pv?
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50 000
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What is the maximum parasitemia for Po?
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30 000
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What is the maximum parasitemia for Pm?
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20 000
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What is the maximum parasitemia for Pf?
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2 500 000
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which plasmodium can have renal complications?
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malariae
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what is the advantage for Pf in sequestration?
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avoidance of spleen
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what are the molecular mechanisms for cytoadherance in Pf?
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knobs -expressed in schizont and trophozoite stages. PfEMP1 is implicated parasite protein
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Stable malaria
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endemic. measurable incidence of transmission
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Unstable malaria
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epidemic. increase in malaria in low endemnicity areas. outbreaks in areas without malaria or among non immune persons
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Premunition
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refers to an immunity that is contingent upon the pathogen being present
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What does duffy negative protect from
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Plasmodium vivax
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How does ovalcytosis protect from malaria?
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in SE Asia, mutation in erythrocyte membrane causes it to become rigid and does not allow parasite in
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How do sickle cell, thalassemia and G6PD protect from malaria?
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oxidative stress causes the erythrocyte to burst before merocytes are mature
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Which drug combo is called the radical cure?
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chloroquine and primaquine
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What are the 3 invasive stages in Plasmodium?
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sporozoites, merozoites and ookinete
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does cryptosporidium have an intracellular stage?
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no, it creates a host membrane by fusing microvilli
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What is TRAP?
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thrombospondin relted anonymous protein. micronemal protein implicated in adhesion of apicomplexa parasites.
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what are the intestinal coccidia?
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cryptosporidium, cyclospora, isospora
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what are the tissue coccidia?
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toxoplasma and sarcocytis
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What are the 2 spp of crytposporidum that infect humans?
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C parvum: can infect cattle and other mammals
C hominis: infects only humans |
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what is the extracytoplasmic location?
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cryptosporidium. microvilli extend and enclose zoite. creates adhesive xone, feeder organelle
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what is cryptosporidum more closely related to?
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gregarines
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What is the pathogenesis of cryptosporidian diarrhea?
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enterocytes killed/damaged (decrease Na absorption); crypt cell hyperplasia (increased Cl secretion); lamina propia inflammation
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How long does it take for the isospora belli oocyst to sporulate?
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<24 hrs
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What is the pathology of Isospora belli?
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villous blunting and crypt cell hyperplasia
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What was cyclospora cayetanensis originally called
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cyano-bacteria like body or big cryptosporidium
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How is cyclospora cayetanensis often transmitted?
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food borne (imported fruit)
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how many sporocysts do you cryptosporidium, cyclospora and isospora have?
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crypto: non (4 sporozoites)
cyclo: 2 (2 sporozoites each) iso: 2 (4 sporozoites each) |
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which coccidia exhibit soil transmission?
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Cyclospora cayetanensis
Isospora belli |
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what is the estimate for Toxoplasma gondii infection worldwide?
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~1/3 world’s population infected
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What is the definitive host for Toxoplasma gondii
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cats
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What is endodyogeny?
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type of cell division in the toxoplasma life cycle in which two daughter cells form within the mother. These are tachyzoites
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What kind of zoites are in the tissue cyst of toxo?
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bradyzoites
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how long after initial infection do bradyzoites appear in toxo?
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10 days
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How many bradyzoites are in cyst?
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1000-2000
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describe the tachyzoites stage in toxo
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acute infection stage
rapid replication reticuloendothelium system is followed by bradyzoite stage |
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describe the bradyzoite stage in toxo
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slow replication
muscle CNS encapsulated (chilin wall) highly infectious |
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What immune response is implicted in the change from tachyzoite (acute) to bradyzoite (chronic) stage?
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strong Th1 response
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At what stage can congenital transmission of toxo occur?
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only the acute stage
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Congenital Toxoplasmosis
when is it most serious, when is it most common |
serious if infection occurs early, most infection happen late in preg
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Ocular Toxoplasmosis
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rarely from primary infection. 20% congenital exhibit at birth, 82% by adolescense
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what fraction of mothers who get toxo during preg pass this on to fetus
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1/3
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What happens to IgM levels in preg with toxo?
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IgM rises the first 8 months following infection and persists for 18 months
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What happens to IgG levels in preg with toxo?
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IgG first appears 1-2 weeks after infection, peaks at 6-8 wks and last for lifetime
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Using IgM and IgG, what are indications of acute toxo infection?
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high IgM and rising total antibody titers along with sympoms
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Using IgM and IgG, what are indications of Chronic toxo infection?
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low or no IgM and stable IgG levers
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What are the rapidly replicating parasites in Sarcocycstis called?
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metrozoites
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What are the slowly replicating parasites in Sarcocycstis called?
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sarcocysts
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Which one is a tick borne parasite?
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babesia
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What are the babesia spp infective to humans?
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B. microti (US)
B. divergens (europe) |
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In which parasite is the tetrad seen?
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babesia, this is called the Maltese cross
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Which one has Strahlenkoerper (ray bodies)?
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babesia
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In which parasite does lack of spleen make infection dangerous?
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Babesia
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What are the piroplasms
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babesia
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What does Naegleria fowleri
cause? |
primary amebic meningoencephalitis (PAM)
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what does Acanthamoeba spp.
cause? |
granulomatous amebic encephalitis (GAE)
granulomatous skin and lung lesions (primarily immunocompromised) amebic keratitis |
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What does Balamuthia mandrillaris
cause? |
GAE + granulomatous skin and lung lesions (primarily healthy)
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Where is Naegleria fowleri found?
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fresh water lakes and ponds
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What are the apical organelles in apicomplexa called?
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polar ring, micronemes, rhoptries
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What are the induction factors for Gametocytogenesis?
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not known, but drug treatment increases numbers, so does immune response
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Where does Gametocytogenesis happen?
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in human host
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Where does Gametogenesis occur?
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mosquito gut
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What factors are involved in the Gametogenesis of plasmodium?
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decrease in temp (2-3 C), decrease in dissolved CO2, increase in pH (8-8.3), MEF (xanthurenic acid)
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IN mosquito, how many days from gametes to sporozoites?
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9-21 days
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What are the invasive stages of Plasmodium and what do they invade?
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merozoites (erythrocytes)
Sporozoites (salivary glands, hepatocytes) ookinete (epithelium [mosquito]) |
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What % of worlds pop lives in endemic malaria zone?
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40%
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How many deaths attributed to malaria per year?
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1.5-2.7 mil
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what are the Prodromal Symptoms of malaria?
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flu-like symptoms. end of incubation period, 2-3 days before 1st paroxysm
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Cold stage of plasmodium
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shivering, cold feeling, last 15-60 min
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Hot stage of plasmodium
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intense heat, throbbing headache, dry burning skin. last 2-6 hours
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Sweating stage of plasmodium
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declining temp, profuse sweating, lasts 2-4 hours.
sleep follows |
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does falciparum exhibit paroxysms?
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not always, can be febrile entire time
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quartan malaria
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febrile paroxysms occur every 72 hours, or every fourth day counting the day of occurrence as the first day of each cycle; due to Plasmodium malariae.
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tertian malaria
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vivax malaria in which the febrile paroxysms occur every 42 to 47 hours, or every third day counting the day of occurrence as the first day of the cycle.
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TNF-α in malaria
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P. vivax: correlation btw fever & serum TNF-α levels. antigens or toxins are released when the infected erythrocyte ruptures and lead to the production of TNF-α and the febrile attacks.
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if someone gets vivax or ovale thru blood transfusion, can there be relapses?
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no, because hypnozoites are produced in the liver stage
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how many merozoites in falciparum?
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up to 36
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Why is parasitemia much higher in falciparum?
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will invade all types of erythrocytes, up to 36 mreozoites, evades immune response in spleen via sequestration
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What type of cells do Pv/Po prefer?
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reticulocytes (young RBC)
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What type of cells do Pm prefer?
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senescent RBC (older)
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What is the molecular mechanism of knobs and cytoadherence in Pf?
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PfEMP1 crosses the erythrocyte membrane and is exposed on the surface
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What may be the 5th human spp of malaria?
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P. knowlesi (malaysia) A. latens could be vector
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Hypoendemic
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areas with low transmission (P=<10%)
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Mesoendemic
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Usually small rural communities with varying intensity of malaria.
P=11-50% |
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hyperendemic
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areas with intense. but seasonal, transmission of malaria
P=51-75% |
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holoendemic
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areas with high degree of year long malaria transmission
P>75% |
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malaia vaccine that targets sporozoite
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anti-infection, prevent liver stage
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malaria vaccine that targets merozoite
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anti-parasite, decrease efficiency of malaria parasite
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malaria vaccine that targets infected erythrocytes
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increase clearance of infected erythrocytes
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malaria vaccine that targets the sexual stages
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anti-transmission, eliminates gametes or prevent infection of mosquitos
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What do you do if malaria blood smear is negative?
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repeat every 12 hours for 48 hours
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How is parasitemia calculated?
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% of infected erythrocytes
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