SLIDE #
TAXONOMY
Phylum Platyhelminthes
Prosthogonimus macrorchis wm
Phylum: Platyhelminthes
Class: Trematoda
Subclass: Digenea
1.1
Order: Plagiorchiida
Family: Prosthogonimidae
Fasciola hepatica wm
Class: Trematoda
Subclass: Digenea
1.2
Order: Plagiorchiida
Family: Fasciolidae
Fasciola hepatica eggs
1.3
Schistosoma mansoni male wm
Class: Trematoda
Subclass: Digenea
1.4
Order: Diplostomida
Family: Schistosomatidae
S. mansoni female wm
1.5
S. mansoni eggs
1.6
S. japonicum eggs
1.7
S. haematobium eggs
1.8
1.9
1.10
1.11
1.12
2.1
2.2
2.3
2.4
2.5
S. mansoni mouse intestine sec
Fasciola hepatica miracidium
Sporocysts sec
Cercariae
Clonorchis sinensis wm
Class: Trematoda
Subclass: Digenea
Order: Plagiorchiida
Family: Opisthorchiidae
C. sinensis eggs
C. sinensis liver sec
Paragonimus westermani
Class: Trematoda
Subclass: Digenea
Order: Plagiorchiida
Family: Troglotrematidae
Paragonimus eggs
LIFE CYCLE INFORMATION
Parasitize oviduct of female birds, wild & domestic
- damages oviducts and can decrease or prevent egg laying
- embryonated egg (via feces) → eaten by snail →
sporocyst → cercaria → dragonfly nymph → bird
Parasitizes liver ruminants & sometimes humans
-inflammation of bile ducts, damage liver
- egg (via feces )→ miracidium → snail → sporocyst →
rediae → cercaria (encyst)→ metacercaria → human (via
eating raw plants)
Parasitize portal vein of large intestine
- embryonated egg (via feces or urine)→ miracidium → snail
→ sporocyst → cercaria → human
- intermediate host specificity
Parasitize veins of small intestine
- embryonated egg (via feces or urine)→ miracidium → snail
→ sporocyst → cercaria → human
- least host specific
Parasitize vein of urinary bladder plexus
- embryonated egg (via feces or urine)→ miracidium → snail
→ sporocyst → cercaria → human
- most host specific
Human liver fluke
- damage bile duct & interferes with liver function
- embryonated egg (via feces) → eaten by snail → sporocyst
→ rediae → cercaria → fish (via skin) → metacercaria →
human
Parasitize human lungs & ectopic sites
- embryonated egg (via feces or sputum)→ miracidium →
snail → sporocyst → rediae → cercaria → crab (via skin or
ingest snail) → metacercaria → human
1
2.6
2.7
2.8
Fasciolopsis buski wm
Class: Trematoda
Subclass: Digenea
Order: Plagiorchiida
Family: Fasciolidae
Fasciolopsis buski eggs
Heterophyes heterophyes wm
Class: Trematoda
Subclass: Digenea
Order: Plagiorchiida
Family: Heterophyidae
Class: Cestoidea
Subclass: Eucestoda
Order: Pseudophyllidea
Parasitizes small intestine of humans
- immunopathologic, obstructive, & traumatic
- egg (via feces)→ miracidium → snail → sporocyst →
rediae →
cercaria (encyst)→ metacercaria → human (via eating raw
plants)
Parasitizes small intestine of fish eating birds & mammals,
including humans
- embryonated egg (via feces) → eaten by snail → sporocyst
→ rediae
→ cercaria (encyst) → fish (via skin) → metacercaria →
human
- 3 developmental stages & 2 intermediate
- oncosphere:
- procercoid: in copepod crustacean hosts
- plerocercoid: in all classes of vertebrates except birds
- adults mainly in fish, but also amphibians, reptiles, birds,
and mammals
-typically has scolex with 2 longitudinal bothria
Class: Cestoidea
Subclass: Eucestoda
Order: Cyclophyllidea
3.1
3.2
3.3
3.4
3.5
- 1 intermediate host: arthropod or vertebrate
- oncosphere:
- cysticercus: in muscle of mammal
- adults mainly in fish, but also amphibians, reptiles,
birds, and mammals
- scolex with 4 acetabula, postovarian vitelline gland,
usually rostellum with hooks
Scolices: Moniezia, Taenia, Dipylidium
Taenia solium scolex
Subclass: Eucestoda
Order: Cyclophyllidea
Family: Taeniidae
Taenia pisiformis comp. wm
Parasites of dogs & wild canids
Subclass: Eucestoda
- gravid proglottids (via feces)→ embryonated eggs ingested
Order: Cyclophyllidea
by rabbit (oncosphere in liver, then cysticerci goes to
Family: Taeniidae
mesenteries and encysts) → dog eats cyst
Cysticercus cellulosae
Taenia saginata eggs
Subclass: Eucestoda
Order: Cyclophyllidea
Family: Taeniidae
Parasites of cows & humans
- gravid proglottids (via feces) or crawl out of anus→
embryonated eggs ingested by cow (oncosphere “hexacanth”
in muscle, then cysticerci develop) → human eats infected
beef
2
3.6
3.7
3.8
4.1
4.2
Echinococcus granulosus wm
Subclass: Eucestoda
Order: Cyclophyllidea
Family: Taeniidae
Echinococcus alveolar cysts
Diphyllobothrium latum mat
Class: Cestoidea
Subclass: Eucestoda
Order: Pseudophyllidea
Family: Diphyllobothriidae
Gyrodactylus sp. Wm
Class: Monogenea
Subclass: Monopisthocotylea
Order: Gyrodactylidea
Family: Gyrodactylidae
Hymenolepis nana eggs
Subclass: Eucestoda
Order: Cyclophyllidea
Family: Hymenolepididae
Hymenolepis diminuta eggs
4.3
4.4
4.5
4.6
4.7
Dipylidium caninum wm
Subclass: Eucestoda
Order: Cyclophyllidea
Family: Dilepididae
Parasites of dogs, related carnivores & infective to humans
- eggs (via feces) → ingested by sheep, deer, moose, other
large herbivores and humans (oncosphere in liver & other
sites where hydatid cyst forms)→ hydatid cyst digested by
canid & scolex attaches to intestine
Parasites of humans, bears, cats, dogs, & possibly other fish
eating carnivores
- egg (via feces)→ coracidia → procercoid in hemocoel of
copepod → plerocercoid in muscle of freshwater fish →
adult in fish-eating mammal (human)
Parasitic on the gills of freshwater and marine bony fish
- have direct development
(no metamorphic changes)
- have a direct life cycle
(no intermediate hosts)
Parasites of rats & infective to humans
- eggs (via feces) → ingested by larval fleas or beetles &
oncosphere in hemocoel (optional intermediate host) → adult
insect ingested by rat
Parasites of rats & infective to humans
- eggs (via feces) → ingested by larval fleas or beetles &
oncosphere in hemocoel → adult insect ingested by rat
Parasites of dogs & infective to humans
- eggs (via feces) → ingested by flea juveniles (oncosphere in
hemocoel, then cysticercoid in adult flea), adult flea ingested
by dog
Dipylidium caninum eggs
Hymenolepis diminuta wm
Hymenolepis sp. Cysticercoid
Subclass: Eucestoda
Order: Cyclophyllidea
Family: Hymenolepididae
Phylum Acanthocephala
Acanthocephalans wm
4.7
Macracanthorhynchus sec
4.8
Phylum Nematoda
Ascaris male & female cs
5.1
Ascaris eggs
5.2
Trichuris trichiura male wm
Subclass: Adenophorea
Order: Enoplida
5.3
Superfamily: Trichinelloidea
Family: Trichuridae
Trichuris trichiura female wm
5.4
Parasites of humans (human whipworm)
Trichuris trichiura
Adult in ileocecal region → unembryonated eggs in feces &
in 2 weeks L1 in egg → L1 in egg ingested & hatches, L1 in
intestinal crypts & 4 molts → adult in ileocecal region
3
5.5
5.6
5.7
5.8
5.9
5.10
6.1
6.2
6.3
6.4
6.5
6.6
Trichuris trichiura eggs
Trichinella male & female
wm
Subclass: Adenophorea
Order: Enoplida
Superfamily: Trichinelloidea
Family: Trichinellidae
Trichinella spiralis muscle sec
Necator americanus male wm
Subclass: Secernentea
Order: Strongylida
Superfamily:
Ancylostomatoidea
Family: Unicinariidae
Necator americanus female
wm
Necator americanus eggs
Ancylostoma duodenale male
wm
Subclass: Secernentea
Order: Strongylida
Superfamily:
Ancylostomatoidea
Family: Ancylostomatidae
A. duodenale female wm
Enterobius vermicularis
female wm
Subclass: Secernentea
Order: Oxyurida
Superfamily: Oxyuroidea
Family: Oxyuridae
E. vermicularis eggs
Dirofiliaria immitis sm
Subclass: Secernentea
Order: Spirurida
Superfamily: Filarioidea
Family: Dirofilariidae
Onchocerca volvulus tumor
sec
Subclass: Secernentea
Order: Spirurida
Superfamily: Filarioidea
Family: Onchocercidae
Parasites of humans, pigs, rats, cats, bobcats, dogs, foxes, and
bears (porkworm)
Trichinella spiralis
Adult in intestinal mucosa → L1 in lymphatics, blood (some
pass out in feces), penetrate skeletal muscle myofibers → L1
in nurse cell, ingested by definitive host & molts 4 times →
adult in intestinal mucosa
Parasites of humans (New World hookworm)
Necator americanus
Adult in small intestine → unembryonated egg in feces & in
24 hrs rhabditiform L1 in soil → 2 molts then L3 in soil –
penetrates skin, travels in blood to the lungs, breaks through
alveolus, coughed up, swallowed, molts twice → adult in
small intestine
Parasites of humans (Old World hookworm)
Ancylostoma duodenale
Adult in small intestine → unembryonated egg in fec es & in
24 hrs rhabditiform L1 in soil → 2 molts then L3 in soil –
penetrates skin, travels in blood to the lungs, breaks through
alveolus, coughed up, swallowed, molts twice → adult in
small intestine
Parasites of humans (human pinworm)
Enterobius vermicularis
Adult in ileocecal region – female migrates to perianal skin
→ unembryonated eggs on perianal skin & in 6 hrs L3 in egg
→ L3 in egg smallowed, hatches → L3 in duodenum – molts
2 times migrates posteriorly → adult in ileocecal region
Parasites of dogs, foxes, wolves, coyotes, and cats (dog
heartworm)
Dirofiliaria immitis
Adult in right heart & pulmonary artery of dog →
microfilariae in peripheral blood – ingested by mosquito,
molts twice → L3 in Malpighian tubules – migrates to
mouthparts, invades bite wound, migrates to heart, molts
twice → adult in right heart & pulmonary artery
Parasites of humans (causes river blindness)
Onchocerca volvulus
Adult in subcutaneous nodules → microfilariae in skin –
ingested by blackfly, molts twice → L3 in flight muscles –
migrates to mouth parts, enters bite wound, molts twice →
adult in subcutaneous nodules
4
Phylum Sarcomastigophora
Entamoeba histolytica cyst
7.1
cyst
- note the presence of 4 or
fewer nuclei; chromatoidal
bars have blunt ends
trophozoite
- note the nucleus with a
central endosome and a fine
peripheral ring of chromatin
Entamoeba coli cyst
cyst
note the presence of more than
7.2
4 nuclei (8 present in mature
cysts); chromatoidal bars have
splintered ends
trophozoite
- note the nucleus with
endosome usually in eccentric
location and larger granules in
ring of peripheral chromatin
Endolimax nana troph
- note the small size and
prominent nuclear endosome
7.3
7.4
7.5
7.6
Iodamoeba buetschlii troph
- note prominent nuclear
endosome & numerous
cytoplasmic vacuoles
Iodamoeba buetschlii cyst
- note oval shape, single
nucleus, prominent nuclear
endosome & one large
glycogen-filled vacuole
Trypanosoma brucei blood sm
Parasites of humans
Entamoeba histolytica
trophozoite in cecum & colon → cyst in feces –ingested →
trophozoite in cecum & colon
Parasites of humans
Entamoeba coli
trophozoite in cecum & colon → cyst in feces –ingested →
trophozoite in cecum & colon
Parasites of humans
Endolimax nana
trophozoite in cecum & colon → cyst in feces –ingested →
trophozoite in cecum & colon
Iodamoeba buetschlii
trophozoite in cecum & colon → cyst in feces –ingested →
trophozoite in cecum & colon
Parasites of humans (African sleeping sickness)
-100% mortality unless treated
Trypanosoma brucei
trypomastigotes in blood – ingested by tsetse fly → dividing
epimastigotes in fly gut → metacyclic trypomastigotes in
fly saliva – fly blood meal → trypomastigotes in blood
Tsetse fly: (Glossina palpalis & G. tachinoides)
5
T. cruzi blood sm
7.7
7.8
Leishmania donovani liver sm
7.9
Giardia lamblia troph
7.10
7.11
Parasites of humans (Chagas’ disease)
Trypanosoma cruzi
intracellular amastigotes (dividing) – burst cell →
trypomastigotes blood (nondividing) – re-invade cell or
ingested by kissing bug → dividing epimastigotes in bug gut
→ metacyclic trypomastigotes in bug feces – rubbed into
bite would or eye → intracellular amastigotes
Kissing bug: (Triatoma gerstaeckeri)
Parasites of humans (kala-azar disease)
Leishmania donovani
dividing amastigotes in macrophage – burst macrophage →
free amastigotes – re-phagocytosed or ingested by sand fly
→ dividing promastigotes in fly gut – injected into bite
wound, phagocytosed → dividing amastigotes in macrophage
Sand fly: (Lutzomyia sp. or Phlebotomus sp.)
Parasites of humans
Giardia lamblia
trophozoite in small intestine → cyst in feces –ingested →
trophozoite in small intestine
Giardia lamblia cysts
Trichomonas vaginalis troph
Phylum Apicomplexa
P. vivax thick sm
8.1
Parasites of humans
Trichomonas vaginalis
trophozoite in urogenital tract → sexual intercourse →
trophozoite in urogenital tract
Parasites of humans
Plasmodium species
Intermediate host: humans
Definitive host: mosquito
Sporozoite in mosquito salivary glands –injected during
feeding → sporozoite in blood – invade hepatocyte →
trophozoite in hepatocyte– mitotic division → schizont in
hepatocyte – hepatocyte bursts → merozoites in blood –
invade RBC → trophozoite in RBC – mitotic division →
schizont in RBC – RBC bursts → merozoites in blood –
reinvade RBC → schizont or gametocyte in RBC –
gametocytes ingested by mosquito → gametes in midgut –
fertilization → zygote – elongation → ookinete penetrates
midgut epithelium, meiotic and mitotic division → oocyst
containing sporozoites – sporozoite migration in hemolymph
→ sporozoites in salivary glands
6
8.2
P. falciparum ring stage sm
8.3
8.4
P. falciparum gametocytes
P. malariae thin sm
Parasites of humans
Plasmodium malariae
Babesia bigemina sm
Parasites of cow and human
Babesia bigemina
Sporozoite in tick salivary glands –injected during feeding →
sporozoite in blood – invade RBC → trophozoite in RBC–
mitotic division → schizont (meront) in RBC – RBC bursts
→ merozoites in blood –reinvade RBC → schizont in RBC –
ingested by tick → merozoite in gut – differentiation →
gametes (ray bodies) in gut – fertilization → zygote –
differentiation → primary kinite – invades organs, divides
→ secondary kinites in various organs – migration in
hemolymph → secondary kinites in salivary glands –
meiotic & mitotic division → sporozoites in salivary glands
Balantidium coli troph
Parasites of humans and
Balantidium coli
trophozoite in large intestine → cyst in feces –ingested →
trophozoite in large intestine
8.5
8.6
8.7
Parasites of humans
Plasmodium falciparum
B. coli cyst
7