Parasites

Question 1

Name the 4 classes of pathogenic protozoa:

Answer 1

1) Sporozoa
2) Amoebae
3) Flagellates
4) Others

Question 2

What kind of protozoa causes malaria?

Answer 2

Sporozoa

Question 3

Name the 4 microorganisms that can cause malaria:

Answer 3

1) Plasmodium falciparum
2) Plasmodium vivax
3) Plasmodium ovale
4) Plasmodium malariae

Question 4

Name typical malaria life cycle:

Answer 4

1) Mosquito bits
2) sporozoites in the saliva glands can get into blood stream
3) sporozoits infect liver cells, reproduces, and kills liver cells so they can enter bloodstream
4) When in the blood stream the parasites can infect red blood cells (called merozoites when in blood stream).

5) In red blood cells the young parasites (trophozoites) divide (nucleus only - erythrocytic schizogeny) - burst and become merozoites again.
6) some of the merozoites don’t become poly-nucleated but become gametozoites (male and female) which can be taken up by mosquitos.
7) Further differentiation of the gametes into male and female + fertilization.

Question 5

Malaria symptoms

Answer 5

1) periods of fever, chills and sweating (called paroxysms).

2) in severe cases multi-organ failæure and cerebral malaria,

Question 6

Malaria diagnosis

Answer 6

1) bloodsmear and staining

2) dipstick tests (RDTs)

Question 7

Malaria treatment:

Answer 7

1) chloroquine (some resistance)
2) artemisinin (from plant)
3) quinine

Question 8

Malaria prophylaxis:

Answer 8

1) atovaquone and proguanil daily
2) daily proguanil and weekly chloroquine
3) mefloquine

All somewhat like quinine

Question 9

What are coccidae?

Answer 9

Parasite like malaria (stages of sexual and asexual reproduction) but not through insect vector.

Question 10

The most important amoeba of humans:

Answer 10

entamoeba histolytica - colonic mucosa is where it infects - bloody diarrhoea called amoebic dysentery (dysentery = blod i afføring).

Question 11

Trophozoite

Answer 11

Active feeding state (tropho greek nourishment)

Question 12

Amoeba treatment

Answer 12

Metronidazole and tinidazole - binds DNA of the amoeba - also usedfor anearobes.

Question 13

Amoeba treatment

Answer 13

Metronidazole and tinidazole - binds DNA of the amoeba - also usedfor anearobes.

Question 14

Name the three main flagellates:

Answer 14

1) Giardia Lamblia - small intestine
2) Trichomonas vagialis - vagina
3) Trypanosomes - insect borne

Question 15

What is a flagellate?

Answer 15

Parasite with one or more flagella.

Question 16

African trypanosomiasis

Answer 16

African sleeping disease - caused by either:

1) trypanosoma brucei gambiensi (west and central africa)
2) trypanosoma brucei rhodesiense (east africa)

Vector = tsetse fly

Question 17

Trypanosomiasis pathogenesis:

Answer 17

1) bitten by infected tsetse fly
2) Parasite goes to the blood - multiply
3) Infection of organs -ending in nervous system and death

Question 18

Trypanosomiasis treatment

Answer 18

arsenicals, melarsoprol or tryparsamide

Question 19

South american trypanosomiasis

Answer 19

1) trypanosoma cruzi
2) vector = bugs
3) Causes chagas disease
4) Invade retiocule endothel - proliferate
5) goes to the heart

Question 20

Leishmania

Answer 20

Species of intracellular (reticuloendothelial) parasite related to trypanosomes but only in 2 forms:

1) Unflagallated - infected lesions
2) flagalleted forms - insect vector

causes skininfection.

Question 21

What is a nematode:

Answer 21

roundworm

Question 22

Name the two major nematode classes:

Answer 22

1) Intestinal nematode

2) Tissue nematode

Question 23

Ascaris lumbricoides

Answer 23

Common roundworm - big worm, male hooked tail - eaten as egg - egg hatch in duodenum - move with circulation to lungs -migrate through trachea to GI-tract where they can survive and mate for a year.

Question 24

Main pathological manifestation of hookworms:

Answer 24

Iron deficient anemia -they drink blood.

Question 25

Name the 5 filarial worms:

Answer 25

1) Wuchereria bancrofti
2) Brugaria malayi
3) Loa loa
4) Onchocerca volvulus
5) Mansonella species

Question 26

Wuchereria bancrofti

Answer 26

Mosquito vector - infects lymphatic (lower limbs) - causes lymphatic edema - samples taken at night because it is here that the worms migrate to the peripheral circulation to coincide with biting times of mosquito (cool)

Question 27

Brugia malayi

Answer 27

Same as wuchereria bancrofti but just in india (bancrofti all over the tropics).

Question 28

Loa Loa

Answer 28

Vector flies in africa - lives subcutaneously - active during day.

Question 29

Onchocerca volvulus

Answer 29

africa + central america - connective tissue (subcutis) - eyes o0ften infected - blindness called river blindness due to where the blackflies that transmit them lives.

Question 30

Microfilariae:

Answer 30

The embryonic (egg) forms of filarial worms.

Question 31

Mansonella species

Answer 31

Biting midges - no sheath

Question 32

What does a filarial sheath refer to?

Answer 32

The sheath the egg has is sometimes kept by the adult worm.

Question 33

Trematodes:

Answer 33

Group of wormsthat have snails as a host. Also called flukes.

Question 34

Trematode life cycle:

Answer 34

1) miracidium - trematode egg contain fully ciliated worm - goes into snail
2) Asexual reproduction in snail as miracidium
3) Develops into cercaria (free svimming body) that goes into fish and forms cysts
4) human eat fish with cyst

Question 35

Treatment of trematodes:

Answer 35

praziquantel

Question 36

Clonorchis sinensis

Answer 36

liver fluke - some bile duct disease. From fish.

Question 37

Fasciola hepatica

Answer 37

liver fluke from sheep

Question 38

Merozoites

Answer 38

A stage where asexual reproduction occurs

Question 39

Sporozoites

Answer 39

sexual stage of protozoa life-cycle.

Question 40

Cyst/oocyst/sporozoite

Answer 40

The “spore” of protozoa

Question 41

Toxoplasma gondii

Answer 41

Protozoa - cat borne (gets it from cysts in prey) - gives it feacally - cats can give it to other farm animals or touch something we touch.

Question 42

What is Taenia?

Answer 42

Genus with tapeworms - two most common:

1) T. saginata (beef tapeworm)
2) T. solium (pork tapeworm)

gotten from eating cystericus (eggs)

Hatch in small intestine - attach to mucosal with 4 suckers in head and hooks - grows backwards from head.

Usually diagnosed by finding work segments in faeces.

treated with praziquantel

Question 43

Diphyllobothrium latum

Answer 43

Fish tapeworm - same as the trematodes.

Question 44

Hymenolepis nana

Answer 44

Dwarf tapeworm - same as Taenia but only 2-4 cm (vs up 10 m)

Question 45

Echinococcus granulosus

Answer 45

Dog/canine tapeworm with sheep (normally) as intermediary host.