Hunter: Schistosomiasis/Malaria Flashcards
What are the 3 major schistosomes?
Schistosoma mansoni
S. japonicum
S. haematobium
What are the 2 minor schistosomes?
Schistosoma mekongi
S. intercalatum
What is the infectious form in humans for schistosomes? Through what route do they invade the human? What is the reservoir?
cercariae; penetrate the skin; snail is the reservoir
Cercarial penetration of skin can cause a transient (blank)
Migration of schistosomules through lungs can cause a (blank) that can be severe in heavy infections
Adult worms in superior mesenteric veins (mansoni and japonicum) and vesicle plexus of bladder (hematobium) cause (blank)
dermatitis; pneumonitis; no clinical symptoms
Onset of egg production causes (blank) (allergic response);
Intestinal or urinary bladder symptoms are due to (blank) passing through tissue to lumen; cause severe hemorrhagic cystitis and gastroenteritis
Eggs swept up portal circulation to liver cause (blank); T cell-mediated delayed hypersensitivity reaction to the eggs
Blockage of sinusoids leads to pipestem fibrosis and (blank)
Katayama fever; eggs; granulomas; portal HTN
3 clinical lab findings in schistosomiasis?
hepatosplenomegaly
eosinophilia
hyperimmunoglobulinemia
List the three symptoms of disease caused by schistosomes
liver and spleen granulomas
fibrosis
inflammation
**all due to eggs trapped in tissues
What drug do you use to treat schistosomes?
praziquantel
This schistosome causes inflammation and fibrosis of the bladder and ureters; obstruction of the ureters leads to hydronephrosis and eventually to uremia
Schistosoma hematobium
These two schistosomes are more likely to infect the gut than the urinary bladder
S. mansoni and japonicum
Compare the structures of S. hematobium, japonicum, and mansoni eggs
S. hematobium: egg comes to a point on one end
S. japonicum: more rounded egg with a tiny bleb hanging off
S. mansoni: spiky bleb coming off of egg
In the life cycle of plasmodium spp, the infectious form delivered from the bite of a mosquito is the (blank). This enters the bloodstream where it is now called a (blank). If it is in the latent stage, it is called (blank). When it infects the liver it is a (blank). When liver cells rupture, they release (blank); when the mosquito takes a meal, it ingests (blank)
sporozoite; merozoite; hynozoite; trophozoite –> schizont; merozoites; gametocytes
When the parasite is undergoing its asexual life cycle in the LIVER from a trophozoite to a schizont, are there any symptoms? When the parasite is undergoing its asexual life cycle in the BLOOD, are there symptoms?
no, no clinical disease during liver stage; yes clinical disease when parasite is in blood
What is the main cytokine responsible for the systemic inflammatory disease that is malaria?
TNF-alpha
What causes the classic fever in malaria?
rupture of RBCs
How often do the fevers occur in the following:
P. falciparum
P. vivax
P. ovale
P. malariea
P. falciparum: daily (malignant tertian)
P. vivax: every other day (benign tertian)
P. ovale: every other day (ovale tertian)
P. malariae: every third day (quartan)
3 important clinical findings in malaria?
anemia
hepatosplenomegaly
hyperimmunoglobulinemia
Which forms of malaria RELAPSE (liver hynozoites re-establish infection)?
Which forms of malaria do not relapse, but RECRUDESCE (subclinical infection becomes clinical disease)?
vivax and ovale relapse;
falciparum and malariae recrudesce
The most common cause of sepsis and septic shock in the world
plasmodium falciparum
What are these?
cerebral coma (schizonts sequestered in brain) anemia pulmonary edema renal failure shock lactic acidosis hypoglycemia tropical splenomegaly maternal death/stillbirth/low birth weight
glomerulonephritis
splenic rupture
complications of P. falciparum
complications of P. malariae
complications of P. vivax
What do malarial parasites do to the shape of the RBC?
they alter the morphology, create knobs
How can you diagnose malaria?
thick and thin blood films
T/F: Mixed infection with P. falciparum and P. vivax can occur
true
Which form of malaria has multiple ring stages and appliqué forms
P. falciparum
Which form of malaria has enlarged erythrocytes with stippling
Plasmodium vivax
Which RBC antigen can determine your susceptibility to vivax malaria?
Duffy blood group
**duffy + (FyA)
Heterozygotes with this condition have increased survival in malaria
sickle cell trait: HbA/HbS
This allele is protective against malaria in West Africa
HLA-B53
This drug kills erythrocytic forms of malaria
chloroquine
This drug kills hepatic forms of malaria (liver hypnozoites) and prevents relapses with vivax and ovale
primaquine
T/F: Drug resistance in malaria is widespread; particularly chloroquine resistance
True
What is used for travelers to prevent malaria?
chemoprophylaxis
Why has malaria not been eradicated?
drug resistant forms of the parasite
mosquito resistance to DDT
Wars and massive population movements
Difficulties in obtaining sustained funding from donor countries
Lack of community participation in host countries
