Non-Microbial Parasites

Question 1

parasitology 101

Answer 1

-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

Question 2

parasitology 101: Human Infection

Answer 2

-Ingestion
-Vector-borne transmission
-Direct contact or Penetration of integument and mucosal surfaces

Question 3

what are parasitic helminths?

Answer 3

worms

Question 4

invertebrates consist of?

Answer 4

-K. Animalia:
-S-K. invertebrata:
–Phylum Platyhelminthes: C. Cestoda, C. Trematoda, C. Turbellaria
–Phylum Nematoda: C. Secernentea, C. “Adenophorea”

Question 5

phylum platyhelminthes are?

Answer 5

flatworms

Question 6

P. Platyhelminthes
what are they?
structure?
whats need to support larval stages?
either?
secrete?
5 taxa

Answer 6

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

Question 7

Tapeworms

Answer 7

phylum platyhelminthes
C. Cestoda:
-Intestinalparasites
– Flat
– Segmented
– Lack digestive systems
– All same general body plan

Question 8

C. Cestoda

Answer 8

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)

Question 9

Taenia spp.
tyoe of?
contains?

Answer 9

type of tapeworm
contains scolex or proglottid variation

Question 10

flukes : C. Trematoda

Answer 10

-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

Question 11

C. Trematoda

Answer 11

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

Question 12

Free Living Flatworms

Answer 12

-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

Question 13

phylum nematoda

Answer 13

roundworms

Question 14

Phylum Nematoda

Answer 14

-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

Question 15

life cycles of free living roundworms (Nematoda)

Answer 15

dw

Question 16

ascariasis

Answer 16

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

Question 17

hookworms

Answer 17

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

Question 18

hookworms morphology

Answer 18

Ancylostoma duodenale
Necator americanus
-Morphology: Only differ in geographical location, Size, Teeth

Question 19

Pinworm

Answer 19

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

Question 20

filariasis

Answer 20

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

Question 21

Trichinosis

Answer 21

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

Question 22

phylum annelida

Answer 22

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

Question 23

leeches

Answer 23

Phlyum Annelida
-C. Hirudinea:
– Freshwater, terrestrial, and marine leeches
– Carry a clitellum
– Hermaphroditic
– Some are hematophagous
-Hirudo medicinalis

Question 24

Phylum Arthropoda

Answer 24

arthropods

Question 25

Arthropods

Answer 25

-Vectors: Organisms that carry pathogens toward other infection targets
-Arthropod vectors: Segmented bodies, Hard external skeletons, Jointed legs
-Vector Types:
– Mechanical (carrier) and Biological (host)
phylum: Arthropoda
S-PL: Chelicerata
Class: Arachnida

Question 26

classes under phylum Arthropoda

Answer 26

-C. Arachnida: Dermacentor spp., Sarcoptes scabiei, Dermatophagoides spp.
-C. Insecta: Ctenocephalides canis, Pulex irritans,
Pediculus humanis corporis, Pthirus pubis

Question 27

C. Arachnida

Answer 27

Arthropods
-8-legged: 2 additional appendages- Chelicerae, Pedipalps
-Exoskeleton
-No antennae or wings
-Spiders, scorpions, harvestmen, ticks, mites, and solifugae

Question 28

Ticks and Mites (Chiggers)

Answer 28

-6-legged juvenile stage
-arthropods
– Endemic worldwide
– Most important bacterial, viral, and protozoan vector: i.e. Borrelia burgdorferi (Lyme disease)
-Long life cycles
–Ticks: Cause Lyme disease, spotted fever, tularemia, encephalitis
-Mites: Cause ricketssial pox and scrub typhus

Question 29

C. Arachnida: Ticks

Answer 29

Tick features:
– “Hardbodied” ticks
– Wait to jump on host: Hunt for skin, Cut open skin (chelicerae), Glue to skin (Hypostome)
– Hematophagou
-Dermacentor variabilis

Question 30

C. Arachnida: Mites

Answer 30

-Itch mite: Sarcoptes scabiei, Scabies, Pruritus
-Life:
– 6-legged larvae migrate to the skin surface and then burrow into molting pouches
– 2 stages of maturation
– M & F mate, F permanently fertilized to lay eggs in burrows
–Dust mite: Dermatophagoides

Question 31

arthropods: Insects

Answer 31

-6-legged
-3 body regions: Head, Thorax, Abdomen
-Large morphology variation: Wing type and amount, Leg size, Mouth feed apparatuses
-Examples: Fleas, Lice, Mosquitoes, Kissing bugs

Question 32

Arthropods: C. Insecta- Fleas

Answer 32

-Fleas: Small, Flat, Wingless
-Most found on rodents and birds
-May carry: Tapeworm Dipylidium, Plague (Yersinia pestis), Transmit viral, bacterial and rickettsial protozoans and helminth diseases to humans and other animals
-Flea systematics are not entirely fixed
– Rep: Pulex irritans

Question 33

Arthropods: C. Insecta- Louse

Answer 33

-Body Lice (Pediculosis)
–Lay their eggs on or near the seams of clothing (Boiling clothes)
– Must feed on blood
– Endemic worldwide
– Spread rapidly under crowded living conditions where hygiene is poor (homeless, refugees, victims of war or natural disasters).
– Infestation is unlikely to persist on anyone who bathes regularly and who has at least weekly access to freshly laundered clothing and bedding.
-Life Cycle:
– Body lice have three forms: the egg (nit), the nymph,
and the adult.
* Nits are lice eggs.
* Nymphs mature into adults about 9-12 days after hatching (Must feed on blood)
* Adults have 6 legs, F lay eggs
– Must feed on blood.
– If they fall off, they die @ RT.
-Crabs are crab louse aka Pthirus pubis