Blood/Tissue Parasites

Malaria, Babesia, Hemoflagellates, filarial worms

malaria characteristics

complications (P. falciparum)

temp spikes 7-10 days after Anopheles mosquito bite

fever episodes: short cold → longer hot period

hemolytic anemia (destroys rbc)

liver & kidney failure

cerebral malaria: dec cerebral blood flow, hypoxia , cytokines → nitrous oxide → consciousness depressor

resp failure

black water fever: rbc’s burst → Hgb into urine → kidney failure

malaria symptoms

paroxysm = cycle of chills, fever & sweating every

3rd day = P. vivax & P. ovale

4th day = P. malariae

36-48h = P. falciparum

malaria recurs after treatment for 3 reasons

1. recrudescence: when prs not cleared by treatment

2. reinfection: indicates complete clearance w new infn established from a separate infective mosquito bite

3. relapse: specific to P. vivax/ovale → re-emergence of blood stage prs from latent hypnozoites in the liver

giant plt

Plasmodium sp compared

LC of malaria

IS / DS?

IS = sporozoites from Anopheles mosquito

DS = ring stage, gametocyte

lab ID of malaria

EDTA (lavender top) tube of whole uncentrifuged blood, must receive w/in 1 hour of collection for sp ID on smear

thick blood smear (scratch method) = use to screen → Giemsa stain (lyses rbc → releases prs)

thin blood smear = to confirm Plasmodium sp → DifQuik stain

+malaria EIA

if past 2hr mark → only do EIA

Plasmodium falciparum

how to ID?

normacytic rbc, multiple rings in rbc (headphone shape)

accole/applique form (rings plaster onto rbc membrane)

gametocyte: banana shape

schizonts: rarely seen in PBP

P. vivax

how to ID?

macrocytic rbc, amoeboid trophs (gets indented by other rbc)

Schuffner’s dots

ring forms

schizonts: 12-24 merozoites clusters

gametocytes: large, circular

P. ovale

macrocytic rbc, fimbriated (comet) rbc

James stippling dots

schizont: 6-14 merozoites

GC: round

ok to say P. vivax / P. ovale bc

same treatment

P. malariae

normocytic rbc, “bird’s eye kinetoplast”

band form

no dots

schizont: 6-12 merozoites (rosette)

Babesiosis

vector = tick (Ixodes, spreads Lyme disease also) blood transfusion, IV drugs

B. microti = causes infn in E. US

B. divergens = Europe

febrile illness like malaria but not cyclic → resolves in month unless i-compromised

Babesia lab ID

typically lots of reticulocytes in smear bc lyses many rbc (see at 10x)

chromatid dots inside & out of rbc

bunny ears or maltese cross

must r/o malaria still

blood/tissue flagellate anatomy

Trypanosoma brucei subspecies rhodesiense vs ssp gambiense

vector

IS

dx

rhodesiense = E. African sleeping sickness → more rapid onset, death

gambiense = W. African sleeping sickness → recurring fever w lymphadenopathy, Winterbottom sign

vector = tsetse fly

IS = metacyclic trypomastigotes

dx: see trypomastigote (pic’d) in body fluid, tissue, LN, blood → if dx, must examine CSF for CNS involvement

American trypanosomiasis (Chagas disease)

vector, IS

caused by Trypanosoma cruzi

vector = Triatomine bugs (kissing bugs) in rural areas of Latin America

IS = inf’d kissing bug takes blood meal → poops metacyclic trypomastigotes in feces near wound

dx: trypomastigotes in blood (larger kinetoplasts comp to T. brucei), ELISA, IFA, EIA, pt hx

Chagas disease pathology

acute: Chagoma, Romana’s sign (swollen eyelid), fever, hepatosplenomegaly

chronic: heart damage, megacolon, enlarged esophagus

Leishmaniasis

GD

vector

IS

m/c forms

subtropic, tropics, southern Europe

v = female phlebotomine sand flies, promastigotes (IS)

m/c form = cutaneous (skin sores), visceral (spleen, liver, BM)

dx: amastigotes inside macrophages in BM or tissue

cutaneous Leishmaniasis

oriental sore = L. tropica complex (urban Middle East, Africa, Mediterranean, Asia Minor, India)

Chiclero ulcer = L. mexicana complex (L America, US)

mucocutaneous Leishmaniasis

espundia = L. braziliensis (Columbia, Ecuador, Brazil)

visceral Leishmaniasis

Kala-azar = L. donovani complex (Asia, Africa, Middle East, Mediterranean, S. America)

hepatosplenomegaly, skin lesions usually not present

dx = splenic or liver biopsy, BM → secondary infn → high mortality rate

Leishmania LC

IS = promastigote

vector = sandfly

Wuchereria bancrofti

GD

vector

warm region: Asia, L. America

v = Culex sp, Aedes sp., L3 larva (IS)

dx: sheathed microfilariae (MF) in blood

W. bancrofti pathology

acute: fever, lymphangitis

chronic: enlarged lower extremities via obstruction of lymph tract from dead worms → elephantiasis of legs, scrotum, etc

Brugia malayi

GD

vector/IS

dx / disease

SE Asia, Asia, India

v = Anopheles mosquito, L3 larvae (IS)

dx: sheathed MF in PB

enlarged upper extremities ie arms

Onchocerca volvulus

GD

v/IS

pathology /dx

Africa, Mexico, Guatemala, Venezuela

v = blackfly (simulium), L3 larvae (IS)

dx: skin scraping to see MF, adult females prefer to ball in subdermis → nodule (walnut sized)

adult worms lodged in lymphatic vessels in subcut tissue → tumors, eyes

Loiasis

caused by Loa-loa (African eye worm), assoc’d Calabar swellings

v = deerflies in West & Central Africa; L3 larve (IS)

dx: MF found in CSF, urine, sputum, blood, feeling across nose bridge, crosses eyeball

Mansonella perstans

GD

v/IS

Latin America, Africa

v = biting midge, L3 larvae (IS)

mostly asympto

dx: MF in PB

Dracunculiasis (Guinea worm disease)

caused by Dracunculus medinensis

v = L3 inf’d-copepods in stagnant water ingested

dx = L1 emerge from lower extremities in water

P. vivax

P. ovale

P. malariae

P. falciparum

Babesia microti