Parasites Flashcards
Name the 4 classes of pathogenic protozoa:
1) Sporozoa
2) Amoebae
3) Flagellates
4) Others
What kind of protozoa causes malaria?
Sporozoa
Name the 4 microorganisms that can cause malaria:
1) Plasmodium falciparum
2) Plasmodium vivax
3) Plasmodium ovale
4) Plasmodium malariae
Name typical malaria life cycle:
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.
Malaria symptoms
1) periods of fever, chills and sweating (called paroxysms).
2) in severe cases multi-organ failæure and cerebral malaria,
Malaria diagnosis
1) bloodsmear and staining
2) dipstick tests (RDTs)
Malaria treatment:
1) chloroquine (some resistance)
2) artemisinin (from plant)
3) quinine
Malaria prophylaxis:
1) atovaquone and proguanil daily
2) daily proguanil and weekly chloroquine
3) mefloquine
All somewhat like quinine
What are coccidae?
Parasite like malaria (stages of sexual and asexual reproduction) but not through insect vector.
The most important amoeba of humans:
entamoeba histolytica - colonic mucosa is where it infects - bloody diarrhoea called amoebic dysentery (dysentery = blod i afføring).
Trophozoite
Active feeding state (tropho greek nourishment)
Amoeba treatment
Metronidazole and tinidazole - binds DNA of the amoeba - also usedfor anearobes.
Amoeba treatment
Metronidazole and tinidazole - binds DNA of the amoeba - also usedfor anearobes.
Name the three main flagellates:
1) Giardia Lamblia - small intestine
2) Trichomonas vagialis - vagina
3) Trypanosomes - insect borne
What is a flagellate?
Parasite with one or more flagella.
African trypanosomiasis
African sleeping disease - caused by either:
1) trypanosoma brucei gambiensi (west and central africa)
2) trypanosoma brucei rhodesiense (east africa)
Vector = tsetse fly
Trypanosomiasis pathogenesis:
1) bitten by infected tsetse fly
2) Parasite goes to the blood - multiply
3) Infection of organs -ending in nervous system and death
Trypanosomiasis treatment
arsenicals, melarsoprol or tryparsamide
South american trypanosomiasis
1) trypanosoma cruzi
2) vector = bugs
3) Causes chagas disease
4) Invade retiocule endothel - proliferate
5) goes to the heart
Leishmania
Species of intracellular (reticuloendothelial) parasite related to trypanosomes but only in 2 forms:
1) Unflagallated - infected lesions
2) flagalleted forms - insect vector
causes skininfection.
What is a nematode:
roundworm
Name the two major nematode classes:
1) Intestinal nematode
2) Tissue nematode
Ascaris lumbricoides
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.
Main pathological manifestation of hookworms:
Iron deficient anemia -they drink blood.
Name the 5 filarial worms:
1) Wuchereria bancrofti
2) Brugaria malayi
3) Loa loa
4) Onchocerca volvulus
5) Mansonella species
Wuchereria bancrofti
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)
Brugia malayi
Same as wuchereria bancrofti but just in india (bancrofti all over the tropics).
Loa Loa
Vector flies in africa - lives subcutaneously - active during day.
Onchocerca volvulus
africa + central america - connective tissue (subcutis) - eyes o0ften infected - blindness called river blindness due to where the blackflies that transmit them lives.
Microfilariae:
The embryonic (egg) forms of filarial worms.
Mansonella species
Biting midges - no sheath
What does a filarial sheath refer to?
The sheath the egg has is sometimes kept by the adult worm.
Trematodes:
Group of wormsthat have snails as a host. Also called flukes.
Trematode life cycle:
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
Treatment of trematodes:
praziquantel
Clonorchis sinensis
liver fluke - some bile duct disease. From fish.
Fasciola hepatica
liver fluke from sheep
Merozoites
A stage where asexual reproduction occurs
Sporozoites
sexual stage of protozoa life-cycle.
Cyst/oocyst/sporozoite
The “spore” of protozoa
Toxoplasma gondii
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.
What is Taenia?
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
Diphyllobothrium latum
Fish tapeworm - same as the trematodes.
Hymenolepis nana
Dwarf tapeworm - same as Taenia but only 2-4 cm (vs up 10 m)
Echinococcus granulosus
Dog/canine tapeworm with sheep (normally) as intermediary host.
