Non-Microbial Parasites Flashcards
parasitology 101
-Live, feed, develop, grow IN or ON another organism
-At organism’s expense
-Medically, socially, economically important
-May involve multiple hosts:
-Definitive host: Mature version of parasite, reproductive stage
-Intermediate hosts: Immature state, various stages of maturation
parasitology 101: Human Infection
-Ingestion
-Vector-borne transmission
-Direct contact or Penetration of integument and mucosal surfaces
what are parasitic helminths?
worms
invertebrates consist of?
-K. Animalia:
-S-K. invertebrata:
–Phylum Platyhelminthes: C. Cestoda, C. Trematoda, C. Turbellaria
–Phylum Nematoda: C. Secernentea, C. “Adenophorea”
phylum platyhelminthes are?
flatworms
P. Platyhelminthes
what are they?
structure?
whats need to support larval stages?
either?
secrete?
5 taxa
Flatworms:
– Macroscopic, multicellular, eukaryotic worms
– Intermediate hosts are often needed to support larval stages
– Adult worms are either dioecious or monoecious
– Secrete large amounts of fertilized eggs =↑ transmission rate
Representative Taxonomies:
-Cestodes (tapeworm)
–Annelids (leeches)
–Nematodes (roundworm)
–Trematodes (fluke)
–Turbellarians
Tapeworms
phylum platyhelminthes
C. Cestoda:
-Intestinalparasites
– Flat
– Segmented
– Lack digestive systems
– All same general body plan
C. Cestoda
tapeworm under phylum platyhelminthes
Scolex: Attachment organ (Suckers, Hooks)
-No mouth
-Cuticle: “Skin”, Nutrient absorption
-Proglottids: Body segments, Mature (Testes + Ovaries which are not auto-fertilizable and self-fertilizable organism)
-Strobila: Collection and sequence of growth of proglottids (Immature, Gravid)
Taenia spp.
tyoe of?
contains?
type of tapeworm
contains scolex or proglottid variation
flukes : C. Trematoda
-kingdom animalia
-S-K invertebrata
-P. Platyhelminthes
-Flat, leaf-shaped
– Lack complete digestive tract (no anus)
– Use a ventral sucker to attach to host and obtain nutrients
– Geographicaldistribution limited
– Grouped by body site parasitized
C. Trematoda
aka flukes, under phylum platyhelminthes
-Genera: Fasciola/Fasciolopsis (Liver Flukes), Schistosoma (Blood Flukes)
-Funfacts:
*Liver flukes: Humans are accidental hosts (Ingest metacercariae from vegetation, Excystment into intestine)
*Blood flukes: Lead to Schistosomiasis (snail fever), 200M cases, Mortality 20K/y, Burrow through skin while in contact with water (Swimmer’s Itch)
– If eggs remain trapped → calcify → Fatal tissue damage
*Diagnosis: Microscopic ID of eggs in stool or urine
*Rx: Praziquantel
Free Living Flatworms
-C. Turbellaria: Kingdom Animalia, S-K invertebrata, Phylum Platyhelminthes
-Bilateral symmetry
–First organisms with eyes and nervous systems
–Planarians are very sensitive to water pollution: Presence in a water sample generally indicates good water quality
–Amazing Adaptation: regenerate many of their body parts, including their heads
phylum nematoda
roundworms
Phylum Nematoda
-Nematodes (roundworms) from Old Aschelminthes
–Macroscopic, multicellular, eukaryotic worms
-Pseudocoelomates
–Complete digestive system
– Most diverse
– Most are dioecious (male and female reprod. system in separate individuals)
-Main group of Nematodes: C. Secernentea, C. Adenophorea
-long, cylindrical, tapering
-Cuticle: Protective layer
-Parasitize almost all vertebrates
life cycles of free living roundworms (Nematoda)
dw
ascariasis
ascaris lumbricoides
-Transmission: Eggs are ingested in water or on vegetables
-Symptoms: Most infections are asymptomatic, Worm burden→abdominal pain and intestinal obstruction
-Diagnosis: Eggs fecally, Larvae in sputum, (rare) Mouth or Nose exit
-Treatment: Albendazole, Mebendazole, Pyrantel pamoate, Surgery
-Prevention: Proper sanitation, Sewage treatment, Hygiene and cooking practices
hookworms
Ancylostoma duodenale
Necator americanus
-Transmission: Eggs passed in stool and hatch, Larvae burrow through skin
-Symptoms: Chronic anemia + protein deficiency
-Diagnosis: Eggs fecally, Anemia / Blood in feces
-Treatment: Albendazole, Mebendazole, Pyrantel pamoate, Surgery
-Prevention: Proper sanitation + Sewage treatment, Avoid bare feet in endemic areas
hookworms morphology
Ancylostoma duodenale
Necator americanus
-Morphology: Only differ in geographical location, Size, Teeth
Pinworm
Enterobius vermincularis
-Transmission: Humans are only host, Female pinworms deposit their eggs in the anus
-Symptoms: Infections are often asymptomatic, Intense perianal itching occurs if symptomatic
-Diagnosis: Early morning/late night, dislodge and collect eggs using tape or cellophane
-Treatment: Mebendazole, Pyrantel pamoate
-Prevention: Prevent scratching and passing of eggs, Proper sanitation, hygiene and extreme care for clothes and food
filariasis
aka elephantiasis
Wuchereria bancrofti
-Filarial worms: Do not infect intestinal tract, but lymphatic system
–Endemic tropically in Africa, India, Asia and S. America
-Infection: Mosquito (microfilariae) bite → circulation →
lower body lymphatic vessels (17 yrs), Day (rest in Lymph); Night (circulation) coinciding with mosquito feeding habits
-Symptoms: Filariasis, Fever chills, Elephantiasis
-Treatment: Diethylcarbamazine
-Diagnosis: Microfilariae in blood smears, Single column of nuclei
Trichinosis
Trichinella spiralis
-Threadworm/Pork worm
-Smallest human nematode parasite
-Symptoms: 12-48h after ingestion mild malaise, 5-10d edema, fever, myalgia, heart damage and death
-Treatment: Albendazole, Mebendazole
-Diagnosis: Muscle biopsy
phylum annelida
segmented worms
-Stereotypical segmented/ringed worm: Macroscopic, multicellular, eukaryotic worms, Ragworms, earthworms, and leeches, Complete digestive system
-Main group (Class) of Annelids:
– C. Polychaeta
– C. Aelosomata: S-C. Oligochaeta, S-C. Hirudinea, S-C. Clitellata
leeches
Phlyum Annelida
-C. Hirudinea:
– Freshwater, terrestrial, and marine leeches
– Carry a clitellum
– Hermaphroditic
– Some are hematophagous
-Hirudo medicinalis
Phylum Arthropoda
arthropods
