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Department of ParasitologyLeiden University Medical Centre
Strongyloides
Lisette van Lieshout
Department of ParasitologyLUMC, The Netherlands
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arasit
ology
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Department of ParasitologyLeiden University Medical Centre
Helminths
Nematodes (roundworm)• Geohelminths• Strongyloides
Cestodes (tapeworm)• Taenia• Echinococcus
Trematodes (flukes)• Schistosoma• Food born trematodesLU
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Department of ParasitologyLeiden University Medical Centre
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arasit
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Department of ParasitologyLeiden University Medical Centre
Case 1
• Child, 5 years old• Born in Vietnam• Recently in the Netherlands, adopted child• Routine stool examination, no complains• Several larvae found
200-300 µm
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Department of ParasitologyLeiden University Medical Centre
Case 2
• Female, 42 years old• Expatriate, several countries in the tropics• Since 7 years in the Netherlands• Suffering from diarrhoea (occasionally bloody)• Abdominal problems, weight loss• More than 7 stool samples examined• Finally some larvae found
200-300 µm
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Department of ParasitologyLeiden University Medical Centre
Case 3
• Male, 62 years old• Born in Suriname, living in the Netherlands since 10 years• Silicosis, intensively treated with corticosteroids• Hospitalised with fever, abdominal pain, nausea• Antibiotics, but no improvement• Patient dies• Autopsy: larvae in feces and in lungs and other organs
500-550 µm
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Department of ParasitologyLeiden University Medical Centre
Strongyloides global distribution
S. stercoralis: estimated 100 million people infected.Atlas of Human Infectious Diseases; H. Wertheim et al.,http://eu.wiley.com/WileyCDA/WileyTitle/productCd-140518440X.htmlLU
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Department of ParasitologyLeiden University Medical Centre
Strongyloides stercoralis
Greaves et al., BMJ (2013)LUMC - P
arasit
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Department of ParasitologyLeiden University Medical Centre
Clinical presentationPrimairy infection
• often asymptomatic (50%)
Chronic stage• general and mild intestinal complains• periods of epigastric pain, diarrhea• eosinophilia (75%)• larva currens (“creeping eruption”)
Hyper infection• fever• severe intestinal symptoms • severe pulmonary symptoms (48-68%)• disseminated: all organs involved
• 83-87% fatal
diagnosis and treatment (Ivermectin)to prevent hyperinfectionLUMC - P
arasit
ology
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Department of ParasitologyLeiden University Medical Centre
Natural course of Strongyloides infection
Concha et al., (2005) J Clin Gastroenterol 39:203
(not HIV/AIDS)
Eosinophilia???LUMC - P
arasit
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Department of ParasitologyLeiden University Medical Centre
LUMC - P
arasit
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Department of ParasitologyLeiden University Medical Centre
Immune reconstitution inflammatory syndrome - debated
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arasit
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Department of ParasitologyLeiden University Medical Centre
Strongyloides diagnosis
Direct smear• Not sensitive !!!!!!
Focused stool examination• Baermann procedure (alternative: cell strain)• Coproculture (alternative: agar plate)
Serology• Screening target patients
PCR (LUMC, increasingly used)
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arasit
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Baermann procedure
L1 larva
L1 larva
L1 = rhabditoid larvae
genital primordium
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arasit
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Department of ParasitologyLeiden University Medical Centre
Differentiation between Strongyloides L1 and L3 larvae
L1 = rhabditoid larvae
lengths: 200-300 µm
short buccal cavity
large genital primordium
lengths: 500-600 µm
motile, slender
long esophagus (>1/3)
no sheath
L3 = filariform larvaeLUMC - P
arasit
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Department of ParasitologyLeiden University Medical Centre
Strongyloides L1 larvae
genital primordium
Short buccal canal
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arasit
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Department of ParasitologyLeiden University Medical Centre
Differentiation between Strongyloides L1 and L3 larvae
L1 = rhabditoid larvae
L3 = filariform larvae
notched tail
NB:
Intermediate stages possible
Morphology deteriorates during storageLUMC - P
arasit
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Department of ParasitologyLeiden University Medical Centre
Intermediate stages of Strongyloides
Sputum of patient with hyperinfection
400 µm lengthsLUMC - P
arasit
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Department of ParasitologyLeiden University Medical Centre
Stool culture
L3 larva
L3 = filariaform larvae = INFECTIOUS
adult worm and L3adult wormL1 larvaLUMC - P
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Stool culture
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Skin penetration ofintestinal nematodes - tropical
Hookworm
65x40 µm
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arasit
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Department of ParasitologyLeiden University Medical Centre
Differentiation between Strongyloides and hookworm larvae
L1 = rhabditoid larvae
200-300 µm
Strongyloides
short buccal cavity
large genital premordium
Hookworm
long buccal cavity
invisible genital premordium
In case hookworm eggs hatched!!!LUMC - P
arasit
ology
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Department of ParasitologyLeiden University Medical Centre
Differentiation between Strongyloides and hookworm larvae
L3 = filariaform larvae
500-550 µm
15-20 µm
500-700 µm
25-35 µm
Strongyloides
motile, slender
long oesophagus (>1/3)
no sheath
notched tail
Hookworm
less motile, less slender
short oesophagus (<1/3)
sheath
pointed tail
Coproculture (4-7 days)!!!LUMC - P
arasit
ology
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Department of ParasitologyLeiden University Medical Centre
Differentiation between Strongyloides and hookworm L3-larvae
LUMC - P
arasit
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Department of ParasitologyLeiden University Medical Centre
Free living nematodes
Not all moving larvae are Strongyloides (or hookworm)
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Department of ParasitologyLeiden University Medical Centre
direct microscopy: cases found by number of slides examined
Nielsen & Mojon 19870
2
4
6
8
10
12
14
16
18
20
5 10 15 20 25 30 35 40 +
Groove, 1989
Requires analysis of multiple samples
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arasit
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Department of ParasitologyLeiden University Medical Centre
Strongyloides – diagnosis Mozambique
Copro-culture
Baermann Positive Negative Total
Positive 56 14 70
Negative 27 206 233
Total 83 220 303
• Baermann = Culture (McNemar P= 0.06)
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arasit
ology
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Department of ParasitologyLeiden University Medical Centre
Strongyloides diagnosis
Direct smear• Not sensitive !!!!!!
Focused stool examination• Baermann procedure (alternative: cell strain)• Coproculture (alternative: agar plate)
Serology• Screening target patients
PCR (LUMC, increasingly used)
LUMC - P
arasit
ology
ESCMID Online Lecture Library
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Department of ParasitologyLeiden University Medical Centre
Diagnosis of Strongyloides infectionby antibody determination
Different formats
(Dis)advantages:Sensitivity vs specificity
Immigrants, screening of specific patients, chronic infections
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arasit
ology
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Department of ParasitologyLeiden University Medical Centre
Real-time PCR StrongyloidesIn house tests
Verweij et al., 2009• 18S ribosomal RNA gen• Specificity 100%• Sensitivity > microscopy (?)• (Ct intensity)
• Implemented > 2006• 250-300 samples/year• 2-4 positive cases/year
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arasit
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0
20
40
60
80
100
%
Cum
ulat
ive
posi
tive s
Microscopy*
PCR
stool1 stool 2 stool 3
Peru: Strongyloides
Verweij et al (in preparation)
* Baermann
La Merced (N=188)LUMC - P
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Department of ParasitologyLeiden University Medical Centre
Strongyloides stercoralis in non-endemic settingsResults Antwerp Travel Clinic N=2591
Microscopy PCR
E. histolytica/E.dispar 99
E. histolytica 13
Giardia lamblia 95 149
Cryptosporidium 12 31
Strongyloides stercoralis 3 21
(Ten Hove et al. 2009)LUMC - P
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Department of ParasitologyLeiden University Medical Centre
LUMC Strongyloides PCR
Routine diagnosis: >2006• Samples/year 250-300 (3 => 1 sample)
2-4 PCR positive cases/year• Feces microscopy + PCR• Serology + PCR
• No microscopy positives missed
Post therapy: ½ - 2 weeks PCR negative
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Department of ParasitologyLeiden University Medical Centre
Ivermectine, 0,2 mg/kg, 1dd, 2-4d
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Strongyloidiasis
• Complex life cycle, autoinfection
• Potentially fatal
• Microscopy: very low sensitivity
• Serology: limitations
• PCR
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