E2- Malaria and Basesiosis Flashcards
What are the 5 important species of Malaria?
Plasmodium vivax P. falciparum P. malariae P. ovale P. knowlesi
What initiates the malaria process in humans?
Injection of Plasmodium sporozoites (motile forms) through transmission of mosquito saliva during a bloodmeal
What migrates to the liver in the bloodstream where they undergo asexual division?
Sporozoites
What is asexual division of sporozoites called?
Schhizogony
What is a vaccine target for malaria?
Sporozoites
What form of malaria can enter RBCs?
Merozoites
Once in RBCs, merozoites enlarge and undergo differentiation to a uninucleate cell. What is this cell called?
Ring trophozoite
As trophozoites age, what can they develop into?
Amoeboid throphozoites
What is a multinucleated cell that produce erythrocytic merozoites called?
Erythrocytic Schizont
What do erythrocytic schizonts produce?
Erythrocytic Merozoites
What occurs after infected RBCs rupture and merozoites escape?
They invade new cells and schizogony begins again or gametogony (sexual cycle) is . initiated
Some merozoites in erythrocytes develop into ____ and do not cause the erythrocyte to rupture?
Gemetocytes
What do malarian organisms consume?
Hemoglobin
What occurs in response to the release of pyrogenic waste following rupture of RBCs schizonts?
Fever and chills
What travels to the hypothalamus and causes an increased thermal set point?
Pyrogen
The release of what intensifies the symptoms of malaria?
Tumor necrosis factor (TNF)
What are some possible symptoms of malaria?
Fever, shivering N/V Diarrhea Anemia (RBC destruction) Hypotension (vasodilation)
What disease produces resistance to malaria?
Sickle cell anemia (parasite has difficulty utilizing abnormal hg)
How are many African Americans and West Africian black person resistance to vivax malaria?
Many lack the duffy antigen, which is a receptor for P. vivax merozoites
What vaccine is available for malaria?
RTS, S (Mosquirix)
What types of malaria is the RTS, S (Mosquirix) vaccine effective against?
P. falciparum
What does the RTS, S (Mosquirix) vaccine target?
Sporozoites
What are some limitation to the RTS, S (Mosquirix) vaccine?
Requires 4 injections
Low efficacy
5 yr half-life (requires half-life)
Expensive
What species of mosquito is a vector for malaria?
Anopheline mosquito (female)
Is there such thing as a carrier state in maleria?
Yes (tolerant carriers contribute to spread)
What may contribute to an increase in malaria cases in the next 50 yrs? Why?
Climate change
New areas exposed to Plasmodium
No host resistance developed
What are majority of malaria cases in the US linked to?
What forms of malaria are majority of the cases?
Travel to Africa
60% falciparum, 20% vivax
What do vivax species tend to infect?
Young erythrocytes (not many RBCs infected)
Patient presents with chills and shaking 10-15 minutes, with increased sweating, anemia, headche, back pain, myalgia, nausea, vomiting, diarrhea and cough. What form of malaria do you suspect?
P. vivax
Relapses of P. vivax infection can result from what?
Activation of liver hypnozoites (can be 3-5 yrs after initial disease)
What stain is used to ID P. vivax?
Venous blood processed with
Giemsa stain
What will a Giemsa stain of venous blood show in a . P. vivax infection?
Enlarged infected RBCs with Schuffner’s dots (surface invaginations and stipling)
What form of malaria is virulent and causes high grade parasitemia because RBCs of any age are infected?
Plasmodium falciparum
What form of malaria can lead to Blackwater fever? What causes this?
Plasmodium falciparum
High parasite numbers
What is Blackwater fever?
High levels of free hemoglobin in urine
Leads to autoimmune reaction in which the host destroys kidney tissue
Chills, fever, rigor, dark to black urine
How does Falciparum malaria lead to capillary obstruction?
Infected RBCs tend to stick to capillary linings
What can capillary obstruction associated with Falciparum malaria cause?
Cerebral malaria
Gastric falciparum malaria
Algid malaria
What does cerebral malaria cause?
Necrosis, hemorrhages, extreme fever, mania, convulsions and death
What does gastric falciparum malaria cause?
Frequent vomiting in addition to other symptoms
What does algid malaria cause?
Skin is cold but internal temperature is high
Can Plasmodium falciparum relapse? Why?
No, no hypnozoite stage
How is Plasmodium falciparum identified?
Erythrocytes with double or multiple ring stages
Crescent shaped gametocyte
Mauerer’s clefts
Many infected cells
In a Plasmodium falciparum infection, young trophozoites and gametocytes are seen in the periphery, but what is not seen?
Not schizonts
Which form of malaria is more virulent?
Plasmodium falciparum
What form of malaria infects older erythrocytes, has paroxysms every 4th day, and has zoonotic from primate reservoirs?
Plasmodium malariae
How is Plasmodium malariae identified?
Trophozoites (basket and band shaped) and schizonts (rosette shaped)
What form of malaria is similar to vivax malaria, has common relapses, and is common to the west coast of Africa?
Plasmodium ovale
What form of malaria is zoonotic, maybe life-threatening if a heavy parasite burden occurs, and is usually found in Southeast Asia?
Plasmodium knowlesi
Why is the incidence of vivax malaria increasing in Africa?
Organism increasingly independent of binding to Duffy antigen
What is the main mechanism of malaria multidrug resistance?
Efflux pumps (more expensive to treat)
What is the causative agent of . Babesiosis, or Nantucket Island Fever?
Babesia microti
There is increasing issues of transmition of Babesia microti through what?
Blood donation
What is the vector for Babesia microti?
Deer tick
Patient presents with malaria like symptoms with small pinpoint lesions and later becomes anemic. What do you suspect?
Babesia microti
What type of malaria is Babesia microti most similar to?
Plasmodium falciparum (but less severe)
How is Babesia microti identified?
Cross-like morphology in RBCs
