helminths Flashcards
(89 cards)
1
Q
intestinal nematodes
A
ascaris lumbricoides enterobius vermicularis trichuris trichiura hookworms (ancylostoma/necator) stronglyoides stercoralis trichostrongylus species cappillaria philippinenesis
2
Q
roundworms
A
un-segmented, bilaterally symmetrical, have a digestive tract size varies separate sexes (males smaller) no intermediate host passed embroynated or embryonate in soil five stages- four larval, one adult
3
Q
ascaris lumbricoides
A
largest, found in intestine, larvae in lungs
vague intestinal, pneumonitis
4
Q
ascaris life cycle
A
eggs hatch in intestine
larvae penetrate gut wall, reach lungs
develop in lung, ascend trachea and are swallowed
reach intestine grow to maturity
5
Q
ascaris eggs
A
fertilized and unfertilized
mammilated or decorticated
6
Q
ascaris pathogenesis
A
host immune response
larval migration
mechanical effects of adult worms
nutritional dificiencies
7
Q
loeffler’s syndrome
A
pulmonary infiltrate in chest x-ray that clear and return, with eosinpophilia
8
Q
enterobius vermicularis
A
most common nematode infection (pinworm)
specimen- scotch tape, pinworm paddle (4-6 to rule out)
9
Q
e. vermicularis eggs
A
flatted on one side, doubtful in O & P
10
Q
e. vermicularis sexes
A
female 8 -13 pointed tail
male 2.5 blunt tail
11
Q
trichuris trichiura
A
seen with ascaris
abdominal cramps, tenesmus, RECTAL PROLAPSE
12
Q
t. trichiura eggs
A
confused with t. vulpus (t. vulpus larger)
barrel-shaped, yellow-brown with 2 polar plugs
13
Q
hookworm species
A
ancylostoma duodenale, necator americanus
if lots of eggs, no larvae (vs. strongyloides)
14
Q
hookworm pathogenesis
A
acquired by SKIN PENENTRATION of larvae
larvae develop in soil and become infectious in 7-10 days
15
Q
hookworm eggs
A
thin shell, oval
identical to strongyloides stercoralis eggs
colorless
16
Q
hookworm larvae
A
rhabditiform long buccal cavity inconspicuous gential primordium 250-350 filariform (infective) 500-700 pointed tail LARVAE MUST BE DIFFERENTIATED FROM STRONGYLOIDES
17
Q
necator vs. ancylostoma
A
necator: cutting blades
ancylostoma: two pair of teeth
18
Q
strongyloides stercoralis
A
strongyloidiasis SKIN PENETRATION OF LARVAE vague intestinal, pneumonitis prefer wet soil, tropic can go undiagnosed (40 years after inf.
19
Q
strongyloides stercoralis life cycle
A
2 life cycle
free-living- rhabditiform –> filariform (infective) in soil, or develop into adults that produce eggs
parasitic- penetrate skin, migrate and swallowed, adults in intestines
AUTOINFECTION- increasing worm burden, leads to disseminated strongyloidiasis (develop into filariform in host, infect intestinal mucosa)
20
Q
hookworm vs. strongyloides
A
filariform
stronglyloides- short buccal cavity
strogyloides- prominent gential promortium
rhabditiform- esophagus
21
Q
stronglyloides clinical disease
A
asymptomatic cutanoeous pulmonary (loeffler's) intestinal immunosuprressive therapy- feemal worms produce eggs and larvae at a faster pace (hyperinfection)- death due to migrating worms
22
Q
stronglyloides key points
A
rhabditiform larve are normally stool concentrate
filariform- short buccal cavity, prominent gential promortium
eggs rarely seen in stool (only heavy inf)
23
Q
trichostronglyus
A
found in herbivores throughout the world,
eggs are ovoid similar to hookworm
24
Q
cappilaria philippinensis
A
parasite of fish eating birds
may have auto infective cycle
eggs have inconspicuous mucoid plug
25
tissue nematoes
```
trichinella spiralis
baylisascaris procyonis
toxcoara canis and cati
ancylosotoma braziliense and caninum
anisakis
dracunculus medinensis
```
26
trichinella spiralis
trichinosis
ingestion of raw or poorly cooked prok, bear, walrus, horse
body site: intestine/muscles, diaphragm, larynx, tongue, jaws, neck, ribs, biceps
can be fata in heavy infection
can be
27
trichinella life cycle
pigs and rodents (humans from raw improperly cooked meat- tissue digested, release larvae
DOESN'T LAY EGGS
LARVAE/ADULTS RARELY SEEN IN intestine
28
baylisascaris procyonis
human baylisascaris
ingesting infective eggs from enviro (eating dirt)
visceral and ocular larva migrans syndromes (in intermediate host)
human infection rare
29
baylisascaris procyonis life cycle
RACCOON- definitive host
| eggs infective in soil after 2-4 weeks
30
Toxocara canis & cati
toxocariosis (visceral & ocular larva migrans)
ingesting eggs in soild contaminated with cat or dog feces
high eosinpophila
small intestine, liver, lungs, brain
31
toxocara diagnosis
biopsy not recommended, serologic test recommended, eggs not seen in humans
32
Ancylostoma braziliense & caninum
DOG HOOKWORMS
cutaneous larva migrans (creeping eruption)
skin penetration of infective filariform larvae
33
Anisakis & Pseudoterranova
```
ANISAKIASIS
ingestion of third stage larve in tissue of inadequately cooked fish
2 intermediate hosts
humans- accidental
definitive- marine mammal
```
34
Anisakis diagnosis
gastroscopic examination (2 cm larvae are removed)
35
Dracunculus mednensis
DRACUNCULIASIS (guinea worm)
ingestion of infected copepods in contaminated water
usually in lower extremities
36
Dracunculus diagnosis
clinical presentation
| rhabditiform larvae seen in fluid discharge (larvae discharged by adult)
37
Filarial nematodes
```
Wuchereria bancrofti
Brugia malayi
Loa loa
Onchocerca volvulus
Mansonella spp.
```
38
Filarial info
arthropod-transmitted
microfilariae- found in blood or skin
eight main species infect huamans
adults produce sheathed microfilariae that reach the blood stream
39
filarial morbidity
three species
wuchereria bancrofti, brugia malayi- lymphatic filariasis
onchocerca volvulus- onchocerciasis (river blindness)
40
nocturnal periodicity
the phenomenon where the highest number of microfilaria occur in the blood at night
41
filarial diagnosis
id of microfiliariaby microscopic examination in blood
+/- sheath, position of the nuclei, shape and distribution of nuclei and size
blood stain with GIEMSA
42
Knott's concentration
concentrate bloods
1 ml of blood, with 10 ml formalin
formalin lyses rbc and straightens microfilariacentrifuge
examine sediment
43
trematodes
```
"flukes"
parasities of vertebrate
adult vary in size
EGGS HAVE OPERCULUM
adults are HERMAPHRODITIC (except schistosomes)
two suckers- oral and ventral
snail- 1st intermediate
many utilize second intermediate
```
44
trematode life cycle
eggs in feces, free-swimming MIRACIDIUM larvae escapes operculum and infects snails
develop into CERCARIAE
cercariae encyst on vegetation and become METACERCARIAE
45
Trematodes categories
intestinal
liver
lungs
blood
46
Intestinal treamtodes
Fasciolopsis buski
Echinostomal ilocanum
Heterophyes heterophyes
Metagonimus yokogawai
47
Fasciolopsis buski
```
giant intestinal fluke disease
aquatic plants (adult in stool in heavy infection)
eggs- broadly oval, yellow-brown
```
48
Echinostoma ilocanum
mollusk
49
Heterophyes heterophyes
freshwater fish
50
Metagonimus yokogawai
freshwater fish
51
Liver & Lung Trematodes
Clonorchis sinensis
Opisthorchis viverrini
Fasciola hepatica
Paragonimus spp.
52
Clonorchis sinesis
Chinese liver fluke disease
bile duct
symptoms: usually none to acute cirrhosis
FISH
53
Eggs of Liver & Lung
similar- definitive diagnosis based on clincal
54
Opisthorchis viverrini
Thaliand and Laos
| Freshwater fish
55
Fasciola hepatica
```
fasciolasis
aquatic plants
body site: bile duct
eggs may be in very low numbers, differentiate from buski by clinical symptoms
(adults in bile duct not in stool)
```
56
Paragonimus westermani
Lung fluke disease
FISH, CRABS, CRAYFISH
Body Site: Lung
no symptoms to chronic cough
57
paragonimus eggs
operculated w/ opercular shoulder
eggs may be coughed in sputum or swallowed and found in stool
NOT INFECTIOUS
58
Blood trematodes
Schistosoma mansoni
Schistosoma haematobium
Schistosoma japonicum
59
Schistosomes
Schistosomiasis
skin penetration by cercariae (not metaciracariae)
in veins of intestine and bladder
60
Sympotms of schistosomiasis
dermatitis and hepatosplenomegaly
61
Schistosoma species
female lies in the male gynecophoral canal
female is longer and more slender
male is more robust
62
Schistosoma eggs
mansoni- prominent lateral projection
haematobium- terminal spine (irnary)
japonicum- spherical w/ minute lateral spine
63
Schisotosome info
eggs can not be detected until after worms mature
biopsy or serological test may be helpful
eggs contain mature miracidia but are not infectious to human (no metacircariae)
MESENTERIC VEINS
eggs cause damage due to spine
64
Cestodes intro
long, ribbon-like and flattened in a cross section
65
Cestode regions
scolex, neck, strobili (chain of proglottids)
66
scolex
attachment organ (for intestinal wall)
equipped with 4 cup-shaped suckers
some species have crown `
67
Neck
region of growth behind scolex that contains germinative tissue
budding zones from which new proglottids are produced
68
Strobila
entire chain of proglottids
proglottids are egg-developing untis that develop from distal end of the scolex
each proglottid contains male and female reproductive system
gravid proglottids are farthest away
69
Taenia saginata "beef tapeworm"
ingestion of infective cysts (cysticercus
| symptoms vague to none
70
Taenia saginata ID
```
5 - 10 m
1000-2000 proglottids
scolex "unarmed" no rostellum
eggs are not infectious, identical to t. solium
15-20 branches/proglottid
```
71
Taenia solium Taeniasis
eating pork contaminated with cysticercus
larvae are digested and attach to intestinal wall
adult worm produces ova in proglottids
eggs, sometimes proglottids are excreted
adult worm usually causes little problem
72
Taenia solium cysticercosis
ingesting infective eggs in porrly cooked pork or through AUTOINFECTION
eggs hatch in small intestine and produce oncosphere larvae that migrate and develop into cysticercoid larvae (high affinity for CNS)
73
Cysticercosis degree of disease
number of cysticerci, location, and immune response to them
| seizures, abnormal behavior, disequilibrium and visual problems
74
Taenia solium ID
```
2-4 meters
800-100 proglottids
scolex "armed" rostellum w/ 2 rows of hooks
proglottids are highly infectious, 7-13
eggs are identical\
```
75
Taenia speciation
scolex
| proglottid (submitted in tap water, stained w/ india ink) based on uterine branches
76
Diphyllobothrium latum
Fish tapeworm
infective larvae in freshwater fish
humans ingest undercook or raw fish containing an encysted plerocercoid larvae
77
diphyllobothrium ID
worm has a scolex with 2 suckers
LARGEST HUMAN TAPEWORM
eggs are unembryonated
CESTODE W/ OPERCULUM
78
Diphyllobothrium latum proglottid
wider than they are long
uterus in the center
passed in chains
79
hymenolepis nana
```
dwarf tapeworm disease
ingestion of eggs (grain beetles)
micre are usual host
more common inn children
ONLY TAPEWORM W/O OBLIGATE INTERMEDIATE HOST
smallest human tapeworm
```
80
hymenolepis nana scolex
armed rostellum
81
hymenolepis nana oncosphere/eggs
6 hooks
proglottids rarely seen in stool
POLAR FILAMENTS
EGGS ARE INFECTIOUS (vs. diminuta)
82
Hymenolpis diminuta
rat tapeworm disease
| ingestion of arthropods
83
Hymenolepisdiminuta
```
human infection rare
diagnosis based on id of eggs
eggs are thin shelled, six-hooked oncosphere
eggs are NOT INFECTIOUS
NO POLAR FILAMENTS
```
84
Diplydium caninum
dog tapeworm disease
| ingestion of arthropoids (fleas on dogs)
85
diplydium caninum eggs/proglottids
proglottids have 2 genital pores (resemble cucumber seeds)
egg packets are very characteristic
not infectious to humans
86
Echinococcus granulosis
```
Hydatid disease
dogs are definitive host
sheep intermediate
Liver (60%), Lungs (20%), kidneys
symptoms depend on cyst location
```
87
Echinococcus granulosis specimen
hydatid cyst fluid
88
Echinococcus granulosus control
avoid feeding raw sheep to dog
89
Echinococcus granulosus eggs
identical to taenia
