Malaria and Babesiosis Flashcards
Most parasitic disease have
Acute and chronic phases
Types of hosts
Host - animal on or within a parasite can establish an infection
Definitive - adult phase or sexual reproductive phase occurs
Intermediates - larval or asexual phase of life cycle…obligatory for completion of life cycle
Accidental - Dead end and cannot reproduce
Periods of parasites
Incubation - time to symnptoms
Prepatent period - time to detection
Patent period - time during which detection can occur in the body
Malaria genus and transmission
Plasmodium
Anopheles mosquito
Species of malaria
Falciparum (most severe and causes most issues)
Vivax - most prevalent
Ovale
Malariae
Restricted to a single vertebrate host
Anopheles mosquito
Only the female can transmit
Bloodmeal needed for eggs
4-5 times during life they will lay eggs
Undergo sexual cycle completion in the mosquito
Life cycle of plasmodium
INfectious form - sporozoite from the mosquio
Then to liver (extraerythrocytic stage with no symptoms)…differentiate and form schizonts which produce merozoites…merozoites are what infect RBCs
Then to erythrocytic stage where symptoms occur…merozoites differentiate to ring stage…trophozoite increases mass by eating and undergoes mitosis without cytokineses…cytokinesis occurs to make RBC schizont…merozoites released and infectious to RBCs
A small subset will become gametocytes that will go back to mosquito to make sporozoites
Thick and thin blood smears
Thick requires more experience
Thin is longer but easier
Detection of malaria
Detection of erythrocytic stages establishes active infection
ID the species
History
Drug sensitivity/resistance profile
Can see ring stage with nucleus at head of the ring
Prepatent periods for each species
Occurs in the liver...up until erythrocytic cycle commences Falcip - 6-12 days Vivax - 10-17 days Ovale - 14 days Malariae - 28-35 days
Basic symptoms of erythrocytic malaria
High fever with periodicity defined by releasing of paraiste from blood cells
Tertain and Quartran malarias
Tertian - vivax and to a degree, falciparum
Quartran - malariae
Number of merozoites released from the liver
Correlates with severity of dz - falcip will have most and malariae has least
IMportant of hemoglobin for malaria
Where most nutrients come for parasitic growht in RBC
Hemoglobin degraded in the food or digestive vacuole…leaves behind toxic heme…detoxed by polymerizing into hemozoin (malarial pigment)
Chloroquine target
Heme polymerization and its inhibition
Plasmodia modification to cell membrane and cytosol
Cell membrane - Knobs that have adhesive ability to bind endothelial cells…important in cerebral malaria
Cytosol - TVN and maurers clefts
Plasmodium falciparum
Incubation of 8-24 days
Pre-patent - 5-12 days
Patent - 4-6 weeks (treated), 18 months (untreated)
Relapses due to erythrocytic stage
Tertian malaria but not always exactly
Infects mature erythrocytes (50,500000 parasites/mL)
As many as 2.5 million
P falcip symptoms
Headache
Coma and death can occur in 24 hours
Can cause cerebral malaria - plasmodium infected erythrocytes stick to capillaries and other RBCs…blockage of blood vessels leads to coma and death
Adhesive properties of cerebral malaria
Knob parasite proteins PfEMP-1 (Var family)
Exhibit antigenic variation which challenges immune system
P falcip in pregancny
Blocks placental circulation to the fetus
Cannot cross the barrier like Toxo gondii
Risk highest for first pregnancy
LEad to fetal anoxia, fetal edema, or abortion after 1st trimester
Renal and P falcip
Blackwater fever with anoxia and acidosis
Hemoglobinuria
Acute renal failure
Mortality - 20-30%
P vivax
Rarely fatal Regular tertian pattern Incubation - 12-18 days Prepatent - 8-17 days Patent - 5-7 years
High potential of rescrudence…due to liver stages (dormant liver schizonts called hypnozoites)
P vivax blood smear
Parasitemia is lower at 20,000/ mL
Infects reticulocytes more often
Enlarged, schauffners dots, and rings
P ovale is similar to P vivax
P malariae
Old erythrocytes
Very long patent period
Reactivation in heptaocytes
Quartan pattern for fevers
Quinine and chloroquine
Block hemozoin ofrmation…attacks erythrocytic stages
Resistance is problem
Used for prophylaxis
Mefloquine
Only in regions with chloroquine and drug resistant forms
Neuro complications???
Erythrocytic cycle
Pyrimethamine and sulfonamides
Uncomplicated malaria…don’t used in SE asia of S america
Proguanil
Component of combination therapy to retard resistance
Doxyclyclin and clindamycin
Target the apicoplast (used in combo with others)
Arteminisin/quinhousu
Last resort in cerebral malaria…high reactivation rates
Atovaquone
Mitochondrial respiration in blood stages
Primaquine
Only one for liver stages
Used to prevent reactivation of all but P falciparum
Babesia
Use mammals as IM hosts
Transmitted by ixodes ticks (same as lyme dz)
No liver stage
Divide by binary fission
Bebesia infection in humans
B microti
Asymptomatic mostly but splenomectomised patients are at highest risk
Between May and Septmeber
Symptoms - fever, generalizxed flu
Incubation - 1-4 weeks, prepatent - 1 weeks
Diagnosis - blood smear
Tx - can used quinine/clindamicin or atovaquone/azithromycin but normally self resolving
What to look for on smear of babesia
Maltese cross
