Malaria and Babesiosis (sessions 26 & 27)

Question 1

How might you contract Malaria?

Answer 1

mosquito-borne disease
Anopheles mosquito (female)

Question 2

Which two species create abt 93% infections?

Answer 2

Plasmodium vivax

P. falciparum

Question 3

Malaria-important species (5)

Answer 3

Plasmodium vivax
P. falciparum
P. malaria
P. ovale
P. knowlesi

Question 4

Malaria life cycle

Answer 4

human phase & mosquito phase
human phase:
1.mosquito injects Plasmodium SPOROZOITES (MOTILE FORMS)during blood meal
2. SPOROZOITES->liver, SCHIZOGONY cycle (rapid asexual cell division releases MEROZOITES)
3. MEROZOITES can infect other liver cells or RBCs
4. ERYTHROCYTIC CYCLE: in RBC, merozoite enlarges, differentiates into UNINUCLEATE cell (RING THROPHOZOITE)
5. as trophoizoites age, the can: develop into AMOEBOID TROPHOZOITES or SCHIZONT (multinucleated cells that produce MEROZOITES)
6. infected RBC ruptures & merozoites escape to invade new cells
7. Either SCHIZOGONY can start again or GAMETOGONY (sexual cycle is initiated)
8. mosquito feeds again, takes in gametes which reproduce sexually within mosquito

Question 5

Malaria-pathogenicity

Answer 5

consumes hemoglobin (fever & chills correspond to release of pyrogenic waste following rupture of RBCs)
pyogen travels to hypothalamus & inc. thermal set point
TNF release intensifies sxs
episodes of 1-2 hrs sever shivering and high fever follows

Question 6

Untreated malaria may progress to

Answer 6

coma, renal failure, respiratory distress & death

Question 7

Malaria host resistance & immunity

Answer 7

no vaccine yet
sickle cell anemia produces resistance to FALCIPARUM malaria
duffy antigen (glycoprotein) is a receptor for P. vivax merozoites (may AA and West Africa black ppl lack the antigen & are resistant to VIVAX malaria)

Question 8

Malari reservoirs and vectors

Answer 8

Reservoirs include humans & simians
Vectors: several species of the night feeding anopheline mosquito
tolerant carrier may play a role in the spread of malaria

Question 9

Plasmodium vivax: aka, gen characteristics

Answer 9

Plasmodium vivax=Benign Tertian Malaria
inc. period 9-15 d, seldom fatal
intext YOUNG ERYTHROCYTES
fever/chills due to rupture of RBC SCHIZONTS
relapses due to activation of LIVER HYPNOZOITES (can be 3-5 y after initial dz)

Question 10

P. vivax epidemiology

Answer 10

most prevalent in tropics
rare in US
ONLY HUMAN RESERVOIR (no other primates)
sickle cell hemoglobin affords nat. protection
43% of worldwide malaria

Question 11

P. vivax identification

Answer 11

venous blood processed w/Giemsa stain
enlarged infected RBCs w/SCHUFFNER’s DOTS (surface invaginations & stipling)
therapy incl. chloroquine, quinine, doxycycline & primaquine

Question 12

Control of P. vivax

Answer 12

w/ protection from mosquitos (nettings, insecticides & repellants)

Question 13

Plasmodium falciparum causes

Answer 13

Malignant Tertian Malaria

Question 14

Plasmodium vivax causes

Answer 14

Benign Tertian Malaria

Question 15

Malignant Tertian Malaria: incubation, description

Answer 15

due to Plasmodium falciparum
inc. period 8-17d
high grade parasitemia
RBCs of ANY AGE are infected
virulent b/c it multiplies rapidly
FEVER is VERY HIGH due to #s of parasites

Question 16

Plasmodium falciparum can lead to which fever

Answer 16

BLACKWATER FEVER

• high levels of free hemoglobin in urine
• leads to autoimmune rxn in which the host destroys kidney tissue
• chills, fever, figor, DARK TO BLACK URINE

Question 17

What can plasmodium falciparum lead to in the capillaries?

Answer 17

falciparum malaria can lead to capillary obstruction as infected RBCs tend to stick to capillary linings

Question 18

Plasmodium falciparum can lead to which 5 things?

Answer 18

Blackwater fever
capillary obstruction
cerebral malaria
gastric falciparum malaria
algid malaria

Question 19

Cerebral malaria characteristics

Answer 19

occlusion of capillaries with parasitized RBCs results in necrosis, hemorrhages, extreme fever, mania, convulsions & death

Question 20

Gastric falciparum malaria is characterized by

Answer 20

frequent vomiting in addition to other symptoms

Question 21

Algid malaria description

Answer 21

skin is cold but internal temperature is high

Question 22

Do relapses occur in Malignant Tertian Malaria?

Answer 22

no b/c there is NO HYPNOZOITE STAGE

Question 23

P. Falciparum identification

Answer 23

erythrocytes w/DOUBLE OR MULTIPLE ring stages, crescent shaped gametocyte, MAURER’S CLEFTS-many infected cells
young trophozoites &gametocytes(BUT NOT schizonts) are observed in peripheral
prompt dx is imp. due to dz severity

Question 24

Quartan malaria is casued by which species

Answer 24

Plasmodium malariae

Question 25

How to identify Plasmodium malaria

Answer 25

Plasmodium malariae is easily identified by TROPHOZOITES (BASKET & BAND SHAPED) & SCHIZONTS (ROSETTE SHAPED)

Question 26

Ovale Malaria: causative species & descriptions

Answer 26

Plasmodium ovale
similar to vivax malaria
relapses are common
(C) to west coast of Africa

Question 27

Plasmodium knowlesi: causes what? & description

Answer 27

Knowlesi Malaria
Zoonotic
may be life-threatening if a heacy parasite burden occurs
(U) found in southeast Asia

Question 28

Babseia microti causes which dz

Answer 28

Babesiosis, or Nantucket Island Fever

Question 29

Nantucket Island Fever: causative spp.

Answer 29

Babesia microti

Question 30

Babesia microti: morphology

Answer 30

“CROSS-LIKE” MORPHOLOGY in RBCs

Morphology & clinical manifestiations similar to Plasmodium falciparum (LESS SEVERE)

Question 31

Babesia microti path & sxs

Answer 31

infects RBCs (cross-like morphology)
Vector: deer tick
malaria-like clinical manifestations (Fever, chills, HA, anemia)
range from asymptomatic to life-threatening (immunocompromised=more problems)
prevalent in New England during warm Months

Question 32

Babesia microti vector

Answer 32

deer tick