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31 Cards in this Set
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Blood and Lymph- Blood, Lymphatic & Tissue Parasites by Jackson
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Blood and Lymph- Blood, Lymphatic & Tissue Parasites by Jackson
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What is the vector for Leishmania? Describe the organism that causes the disease. And the types.
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Vector is the sandfly. It bites and gives you a flagellated protozoa that multiplies in the macrophages. Most common type is the cutaneous one, which begins with red papule, itch, enlarges and ulcerates; scar.
Mucuocutaneous is just like cutaneous but also goes in the mucous membranes. The most serious form is the visceral (fever, chills, sweats, anemia, diarrhea, organ involvement) |
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What happens when the protozoa enters the macrophage?
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Loses its flagella.. now it's in the amastigote stage. It will replicate asexually, rupture and lyse the cell, and destroy tissue, causing immune reactions
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What is the significance, in terms of the development of immunity, of the antigenic variation displayed by Trypanosomes?
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They have a way of changing their protein coat as a way of avoiding immune detection and elimination. Once they are recognized, they start to change their surface glycoprotein (variant surface glycoprotein VSG). Inhibits us to develop a vaccine.
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Describe the predominant clinical presentations of Chagas disease.
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Chagas Disease :
-Asymptomatic, acute or chronic -Chagoma, with rash and periorbital edema -Fever, chills, malaise, myalgia and fatigue -Hepatosplenomegaly, myocarditis, megacolon and megaesophagus poops near your mouth, you scratch and get the infection. *can result in severe cardiomyopathy **seen in South/Central America |
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What is the vector for leishmaniasis? trypanosomiasis?
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leishmaniasis- sandfly
trypanosomiasis sleeping sickness- tsetse fly Chaga's- kissing bug (reduviid bug) |
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What is the worst thing about Sleeping Sickness?
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Sleeping Sickness - Ulcer at site of fly bite; fever and lymphadenopathy; CNS involvement with lethargy, tremors, mental retardation, convulsions, coma, and death
West takes a long time; East moves a lot faster from infection to death (and affects animals more) |
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Briefly describe the schistosoma life cycle, especially regarding human infection.
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Once in the human, the cercariae changes forms. Goes from the skin to subq tissue, to lungs (cause coughing), blood vessels, portal system of liver, where the adult worms form. There in the portal system, the worms mate, make eggs, and the eggs eat their way through tissue, go to the GI tract and feces, urinary tract and urine, to contaminate the water and start the cycle again.
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How do humans become infected with Schistosomes?
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Humans are infected by the cercariae form of the schistosoma which is found in contaminated waters and penetrates in tact skin. This cercariae form is released from a snail.
The contaminated water has human feces. The organisms in the water go into the snail (intermediate host), develops the cercariael stage, then goes into intact skin. |
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How do these adult worms protect themselves?
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They can mask themselves with human antigens. They can cover themselves on the surface with MHC antigens to hide from immune response. So once they hit the adult stage, there isn't much reaction against the worms. The problems are the eggs (a lot of response, Th2, IgE, eosinophils, granulomas etc). Leads to swelling of liver and spleen, ascites, so it can be a fatal disease because of the reaction against the eggs.
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What gives you lymphatic filariasis?
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infective larvae (wucherieria and brugia species) injected by mosquitos. needs to be repeated infections to be a problem, so it's really a problem with local inhabitants, and not passers by.
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When these adult worms migrate to the lymphatics in humans, what can result?
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elephantitis from blockage of the lymphatics.
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What gives you 'river blindness?'
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onchocerciasis is from the onchocerca volvulus, transmitted by the bite of a blackfly.
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ulcerated skin lesions
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Leishmania
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transmitted by blackfly vector
eosinophilia |
onchocerca
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lymphatic blockage
mosquito vector eosinophilia |
wuchereria -->elephantitis
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cardiomyopathy
feces from kissing bug (american) VSG, antigenic variation (african) |
trypanosoma
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infective form penetrates skin
fever, malaise, rash, splenomegaly eosinophilia |
Schistosoma
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What is the vector to spread malaria?
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Anopheles mosquito. The infected form is called the sporozoite, will get into the bloodstream and into the liver very quickly (within an hour).
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What are the species that causes malaria in humans?
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Plasmodia organisms...
P. falciparum (40-60% of cases, >95% of fatalities) P.vivax P. malariae P. Ovale |
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Start talking about the life cycle...
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Once the sporozoite enters the liver, asexual reproduction occurs producing thousands of merozoites, and it is this form that infects erythrocytes. Most of the clinical manifestations of malaria are from the merozoites infecting the RBCs. Once they fill the RBC, they can lyse it, releasing more merozoites into the bloodstream to infect other RBCs. This can become synchronous with a lot of RBCs lysing at the same time, eliciting inflammatory reactions, fever chills, affecting kidney, etc.
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What happens with the merozoites that develop into the sexual form?
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These are called gametocytes. They are in the bloodstream and can be ingested by another mosquito (taking a blood meal), develop in the mosquito's gut, and again into the sporozoite form, which can go into the salivary gland and injected into the next person.
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What does P. falciparum do to make it the most dangerous form of malaria?
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Once it's inside the RBCs, it changes the surface, making them sticky, which tends to plug up the capillaries.
It has a higher level of parastiemia in the RBCs than the other forms. Infects all RBCs, young and old. Has unique banana shaped gametocyte. |
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Prevention of malaria
Vaccine? |
use mosquito nets.
Most malarial deaths are from young children. But after a while, people build immunity. So there's an immune response that decrease clinical manifestations of malaria. There's hope, but there is no commercially available one. |
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What is the vector for babesiosis? How does this compare to malaria?
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Tick vector, not mosquito.
There is no liver stage before there's the invasion of the RBCs. Maltese Cross form on erythrocytes |
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What are the symptoms if any of babesiosis? Who is particularly at risk for being killed by this?
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Malaise, fever, chills, sweating, arthralgias, headache, myalgias, fatigue
Potentially fatal especially to those who have had their spleen removed. |
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Who is the host for toxoplasma gondii?
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Cats are the definitive hosts. Immature oocysts in cat feces
Several forms — trophozoite, cyst, oocyst, sporozoite |
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Ataxia, muscle weakness, MRECL in frontal love and cerebellum, HIV+
what are you thinking about? |
toxoplasmosis. if the pt is seronegative for toxoplsma, you can still think toxoplasmosis bc the HIV has dampened the immune response so you couldn't get a good serological response.
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Toxoplasma gondii — transmission to Humans via:
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Accidental ingestion of oocysts
Ingestion of uncooked meats In utero (pregnant women dont handle kitty litter) -Hydrocephalus or Brain calcifications if first trimester. Blood transfusion/Organ transplant mostly asymptomatic unless immune deficient, may look like mononucleosis |
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Form of plasmodium that can persist in the liver for a long period of time. What is this called?
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hypnozoite. so you can have the emergence of the infection years later.
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If this is malaria, what stage of the organism was injected into this patient by an infected mosquito to start this infection?
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Sporozoite
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