Strongyloidiasis Flashcards
Strongyloidiasis is caused by what
strongyloides stercoralis
what is the fourth most important nematode infection in the world
strongyloides stercoralis
what is the mortality for strongyloides stercoralis
Dissemination in immunocompromised patients and those receiving
corticosteroids (mortality up to 85%)
what caused diarrhee de la cochinchine
Strongyloides
what are the names of Strongyloides
Bavay named Anguillula stercoralis and then Anguillula intestinalis
who established the genus strongyloides
grassi
who elucidated the life cycle of
Fulleborn (1911), Kreis (1932) and Faust (1933)
what does S procyonis (raccoon) do
Threadworms, heterogenetic, free-living and parasitic generations, include
at least 40 named species)w
what is the main strongyloides species
S. stercoralis
how many people are infected with strongyloides
370 million of people
where is strongyloides
- All tropical and subtropical regions
- Europe (Northern Italy, France, Spain, Switzerland, Poland)
- USA (Appalachian region, West Virginia)
- Japan (Okinawa)
- Australia (aboriginal populations)
explain life cycle strongyloides
-autoinfection
-homogonic cycle
heterogenic cycle
The first-stage juveniles (J1) often are referred to as
rhabditiform because posterior
end and esophagus separated by a prominent bulb.
how big is the free living female strongyloides
2-3 mm long
37 um wide
what is the lenght of free living strongyloides
0.9mm
why is strongyloides unique
has a free-living life cycle and
an autoinfective cycle in addition to the normal parasitic type life cycle.
what are the hosts of strongyloides
Natural: Humans
other primates
dogs
cats
Experimentally:
gerbils
Patas monkeys
SCID mice
reproduction of strongyloides
-Parasitic adults are parthenogenetic.
-Free-living adults are sexual.
where does the stronfyloides female live
in the small intestibe in the epithelial mucosa and the crypts of liberkuhn
true or false: in strongyloides, the eggs are embryonated when laid
yeah it is L1
in strongyloides, which stage is the one in which life history decisions are made
L1
how big are the strongyloides eggs
(50-58 um by 30-34 um)
what does L1 have in terms of physical things
-esophagus
-genital primodium
what is the autoinfective stage in strongyloides
L3a
has an intestine and a filariform esophagus
autoinfection of strongyloides: triggers
- Corticosteroids (prednisone)
- Immunosuppression (tacrolimus)
- Neonatal infections
- Infections with transplanted adults
- Co-infection with Th-1 inducing pathogens
- Massive initial infections
- Intestinal stasis
Homogonic (direct) development
vs
Heterogonic (indirect) development of strongyloides: determinants
- Immune status of the host
- Environmental parameters
- Presence of food
Third stage infective larva (L3i): behavior
- Positively thermotacic
- Attracted to salt
- Increased movement in presence of CO2
- Attracted to urocanic acid
- Positively geotactic
Migration starts with a “layover” in the skin for strongyloides
1-2 days
migration from the skin takes how long for strongyloides
4 days
in strongyloides how long does it take for the larva to reach the small intestine
5-6 days
how long does to take for stringyloides to reach l4
4 days
young adults of strongyloides in the intestine at … days post infection
7 days post infection
to see l1 in feces for strongyloides how long does it take
10-14 days lol
CUTANEOUS MANIFESTATIONS of strongyloides
- Urticarial rashes
- Migratory serpiginous dermatitis
- Periumbilical cutaneous purpura
pulmonary manifestations of strongyloides
- Diffuse bronchopneumonia
- Intra-alveolar hemorrrhage
GI manifestation of strongyloides
- Epigastric abdominal pain
- Postprandial fullness
- Heartburn
- Brief episodes of diarrhea
- Malabsorption
diagnostic challenges of strongyloides
-fatal disease in immunocompromised and lifelong autoinfection
-intermittent larval excretion
-insensitivity of standard lan techniques
-insensitivity of our best larva finding technique aka agar plate
-no available gold standard test like ag capture, pcr
-non specificity of standard strongyloides serologies
true or false: there is. a test recombinant antigen for strongyloides
yeah
20 Canadian children between age 3 and 16 with eosinophilic oesophagitis, how many were seropositive for strongyloides crude antigen
45%
-but they never travelled to strongyloides endemic areas
-The parents and embarrassingly non-specific serology
Specificity Testing of Strongyloides Recombinant Antigen serology what are the advantages
.. no endemic Strongyloides stercoralis
.. Plenty of trichinellosis in Arctic (non-travellers)
.. Plenty of other eosinophilic enteridides (eg Eosinophilic esophagitis)
.. Some sylvatic hydatids
.. Very rare human dirofilariasis
Specificity Testing of Strongyloides Recombinant Antigen serology what are the disadvantages
.. Southern Canada endemic for Strongyloides procyonis (in
raccoon)
.. Other endemic Canadian helminths include Echinococcus
granulosis (sylvatic), Toxocara canis, Baylisascaris
procyonis, Diphyllobothrium spp.
TREATMENT for strongyloides
- Ivermectin: 200 ug/kg per day
- Thiabendazole: 50 mg/kg per day
- Albendazole: 400 mg orally for adults and 15mg/kg per day for children
Transmission of HTLV-1 occurs through
breast feeding, sexual intercourse, transfusion of contaminated blood products or sharing of contaminated syringes and needles.
HTLV-1: Human T-cell-lymphotropic virus (endemic….
in Japan, Africa, the Caribbean and South America
Patients with strongyloidiasis and HTLV-1 co-infection (n = 12) had more……
Strongyloides stercoralis larvae found in stool when compared to strongyloidiasis-only patients
Increased proportions of regulatory T cells in strongyloidiasis/…
HTLV-1 co-infected patients.
…… responses to larval Strongyloides stercoralis antigens are decreased in
patients with strongyloidiasis and HTLV-1 co-infection compared to HTLV-1
negative subjects with strongyloidiasis
IL-5
Increased numbers of regulatory T cells correlates with reduced….
IL-5 responses to Strongyloides Stercorarius larval antigens
the hyperinfection is has a high mortality rate of?
15-87%
what are the risk factors for hyperinfection syndrome
-predisposing conditions
-htlv-1 infection
which immune response is inhibited caused by hyperinfection syndrome
th2 cell mediated
recommendations for strongyloides
-Immigrant…screening
-Investigating peripheral eosinophilia
-Chemotherapy Pre-immunosuppression screening
-Human T-lymphotropic virus type 1 (HTLV-1) patient
-Strongyloides post-treatment follow-up
