Helminthology Nematodes Nematodes Helminthology Strongyloides - - PowerPoint PPT Presentation

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Helminthology Nematodes Nematodes Helminthology Strongyloides - - PowerPoint PPT Presentation

May 25, 2023 366 likes •639 views

Helminthology Nematodes Nematodes Helminthology Strongyloides Strongyloides Terry L Dwelle Dwelle MD MPHTM MD MPHTM Terry L Classification of Nematodes Classification of Nematodes Superfamily Genus and Species Probable

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Helminthology Helminthology – – Nematodes Nematodes Strongyloides Strongyloides

Terry L Terry L Dwelle Dwelle MD MPHTM MD MPHTM

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Classification of Nematodes Classification of Nematodes

Subclass Subclass Order Order (suborder) (suborder) Superfamily Superfamily Genus and Species Genus and Species Probable Probable prevalence in prevalence in man man

Secernentea Secernentea Rhabditida Rhabditida Rhabditoidea Rhabditoidea Strongyloides Strongyloides stercoralis stercoralis 56 million 56 million Stronglyloides Stronglyloides myoptami myoptami Occasional Occasional Strongyloides Strongyloides fuelloborni fuelloborni Millions Millions Strongyloides Strongyloides pyocyanis pyocyanis Occasional Occasional

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General Information General Information

► ► Primarily a disease of tropical and subtropical

Primarily a disease of tropical and subtropical areas, highly prevalent in Brazil, Columbia, and SE areas, highly prevalent in Brazil, Columbia, and SE Asia Asia

► ► It is not uncommon in institutional settings in

It is not uncommon in institutional settings in temperate climates ( temperate climates (eg eg mental hospitals, prisons, mental hospitals, prisons, children children’ ’s homes) s homes)

► ► Serious problem in those on immunosuppressive

Serious problem in those on immunosuppressive therapy therapy

► ► Higher prevalence in areas with a high water table

Higher prevalence in areas with a high water table

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General Recognition Features General Recognition Features

► ► Size; parasitic female 2.7 mm, free living female

Size; parasitic female 2.7 mm, free living female 1.2 mm, free living male 0.9 mm 1.2 mm, free living male 0.9 mm

► ► Eggs

Eggs – – 50 50-

  • 58 X 30

58 X 30-

  • 34 um

34 um

► ► The

The Rhabdiform Rhabdiform larvae have a shorter larvae have a shorter buccal buccal canal canal vs vs hookworm hookworm

► ► Larvae have a double lateral

Larvae have a double lateral alae alae, smaller than , smaller than hookworm hookworm

► ► S.

  • S. fuelloborni

fuelloborni – – free living female has a distinct free living female has a distinct post post vulvar vulvar constriction constriction

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Manson’s Tropical Diseases, GC Cook, 12th Edition, Saunders, pp 1627

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Buccal Space Double Lateral Alae

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Life Cycle Life Cycle

► ►Definitive host

Definitive host

  • S

S stercoralis stercoralis -

  • man, dogs, primates

man, dogs, primates

  • S

S myoptami myoptami – – nutrea nutrea

  • S

S fuelloborni fuelloborni – – man, primates man, primates

  • S

S pyocyanis pyocyanis – – man, raccoon man, raccoon ► ►Stage leaving the body

Stage leaving the body – – Rhabdiform Rhabdiform larvae larvae

► ►Infectious stage for the definitive host

Infectious stage for the definitive host – – L3 L3 filariform filariform larvae larvae

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Life Cycle Life Cycle

Lungs Trachea Intestine

Penetrates the mucosa 2 molts – 2 weeks

Adults mate Eggs produce Crypts of Lieberkuhn L1 Rhabditoid larvae hatch Stool L3 Filariform Larvae Colonic mucosa

Internal Autoinfection

L3 Filariform Larvae

Perineal skin

Skin

External Autoinfection

Soil

Warm and moist

L3 Filariform Larvae

Soil 24-36 hours

Soil – Direct Development

Free living rhabditoid adults

Male and female – 3-5 days

Eggs produced L3 Filariform Larvae

Soil – Indirect Development

Life Cycle

In bronchial mucosa

L3 Filariform Larvae

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Life Cycle Life Cycle

Lungs Trachea Intestine

Penetrates the mucosa 2 molts – 2 weeks

Adults mate Eggs produce Crypts of Lieberkuhn L1 Rhabditoid larvae hatch Stool L3 Filariform Larvae Colonic mucosa

Internal Autoinfection

L3 Filariform Larvae

Perineal skin

Skin

External Autoinfection

Soil

Warm and moist

L3 Filariform Larvae

Soil 24-36 hours

Soil – Direct Development

Free living rhabditoid adults

Male and female – 3-5 days

Eggs produced L3 Filariform Larvae

Soil – Indirect Development

Life Cycle

In bronchial mucosa

L3 Filariform Larvae

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Life Cycle Life Cycle

Lungs Trachea Intestine

Penetrates the mucosa 2 molts – 2 weeks

Adults mate Eggs produce Crypts of Lieberkuhn L1 Rhabditoid larvae hatch Stool L3 Filariform Larvae Colonic mucosa

Internal Autoinfection

L3 Filariform Larvae

Perineal skin

Skin

External Autoinfection

Soil

Warm and moist

L3 Filariform Larvae

Soil 24-36 hours

Soil – Direct Development

Free living rhabditoid adults

Male and female – 3-5 days

Eggs produced L3 Filariform Larvae

Soil – Indirect Development

Life Cycle

In bronchial mucosa

L3 Filariform Larvae

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Life Cycle Life Cycle

Lungs Trachea Intestine

Penetrates the mucosa 2 molts – 2 weeks

Adults mate Eggs produce Crypts of Lieberkuhn L1 Rhabditoid larvae hatch Stool L3 Filariform Larvae Colonic mucosa

Internal Autoinfection

L3 Filariform Larvae

Perineal skin

Skin

External Autoinfection

Soil

Warm and moist

L3 Filariform Larvae

Soil 24-36 hours

Soil – Direct Development

Free living rhabditoid adults

Male and female – 3-5 days

Eggs produced L3 Filariform Larvae

Soil – Indirect Development

Life Cycle

In bronchial mucosa

L3 Filariform Larvae

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Life Cycle Life Cycle

Lungs Trachea Intestine

Penetrates the mucosa 2 molts – 2 weeks

Adults mate Eggs produce Crypts of Lieberkuhn L1 Rhabditoid larvae hatch Stool L3 Filariform Larvae Colonic mucosa

Internal Autoinfection

L3 Filariform Larvae

Perineal skin

Skin

External Autoinfection

Soil

Warm and moist

L3 Filariform Larvae

Soil 24-36 hours

Soil – Direct Development

Free living rhabditoid adults

Male and female – 3-5 days

Eggs produced L3 Filariform Larvae

Soil – Indirect Development

Life Cycle

In bronchial mucosa

L3 Filariform Larvae

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Forked Tail Stronglyloides Adult Alveolar lining Strongyloides Infiltrate

Eggs Larva

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Life Cycle Life Cycle

Lungs Trachea Intestine

Penetrates the mucosa 2 molts – 2 weeks

Adults mate Eggs produce Crypts of Lieberkuhn L1 Rhabditoid larvae hatch Stool L3 Filariform Larvae Colonic mucosa

Internal Autoinfection

L3 Filariform Larvae

Perineal skin

Skin

External Autoinfection

Soil

Warm and moist

L3 Filariform Larvae

Soil 24-36 hours

Soil – Direct Development

Free living rhabditoid adults

Male and female – 3-5 days

Eggs produced L3 Filariform Larvae

Soil – Indirect Development

Life Cycle

In bronchial mucosa

L3 Filariform Larvae

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Life Cycle Life Cycle

Lungs Trachea Intestine

Penetrates the mucosa 2 molts – 2 weeks

Adults mate Eggs produce Crypts of Lieberkuhn L1 Rhabditoid larvae hatch Stool L3 Filariform Larvae Colonic mucosa

Internal Autoinfection

L3 Filariform Larvae

Perineal skin

Skin

External Autoinfection

Soil

Warm and moist

L3 Filariform Larvae

Soil 24-36 hours

Soil – Direct Development

Free living rhabditoid adults

Male and female – 3-5 days

Eggs produced L3 Filariform Larvae

Soil – Indirect Development

Life Cycle

In bronchial mucosa

L3 Filariform Larvae

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Life Cycle Life Cycle

► ►

All All filariform filariform larvae can swim larvae can swim

► ►

Generally Generally strongyloides strongyloides has a lower prevalence than has a lower prevalence than hookworm hookworm

► ►

Strongyloides Strongyloides L3 L3 filariform filariform larvae are not infectious by the larvae are not infectious by the

  • ral route except for S
  • ral route except for S fuellobourni

fuellobourni

► ►

Adults are more commonly affected than children Adults are more commonly affected than children

► ►

The infection usually occurs through exposure to infected The infection usually occurs through exposure to infected soil soil

► ►

Transmission by breast milk has been demonstrated in Transmission by breast milk has been demonstrated in animals and is likely in man animals and is likely in man

► ►

Prepatent Prepatent period period – – 4 weeks 4 weeks

► ►

Patent period Patent period -

  • 30 + years

30 + years

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Clinical Presentation Clinical Presentation

► ►Half of the cases are mildly symptomatic or

Half of the cases are mildly symptomatic or asymptomatic asymptomatic

  • Recurrent rash

Recurrent rash – – Larvae Larvae currens currens – – starts from starts from the the perianal perianal area and moves rapidly (10 cm / area and moves rapidly (10 cm / day) to buttocks, thighs and trunk day) to buttocks, thighs and trunk

  • Urticaria

Urticaria

  • Gastrointestinal complaints

Gastrointestinal complaints – – mimics peptic mimics peptic ulcer, RUQ pain ulcer, RUQ pain

  • Chronic pulmonary symptoms

Chronic pulmonary symptoms

  • Eosinophilia

Eosinophilia

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SLIDE 18
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Clinical Presentation Clinical Presentation

► ►Severe infection

Severe infection – – immunocompromised immunocompromised

  • May cause fatal

May cause fatal hyperinfection hyperinfection

  • Gastrointestinal

Gastrointestinal – – diarrhea, constipation, diarrhea, constipation, abdominal pain, nausea and vomiting, abdominal pain, nausea and vomiting, malabsorption malabsorption (fat, B12, protein losing (fat, B12, protein losing enteropathy enteropathy) )

  • Hypereosinophilia

Hypereosinophilia resembling tropical resembling tropical pulmonary pulmonary eosinophilia eosinophilia (TPE) (TPE)

  • Leukocytosis

Leukocytosis

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SLIDE 20

Larvae

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Differential Diagnosis Differential Diagnosis

► ►Ascaris

Ascaris

► ►Hookworm

Hookworm

► ►Schistosomiasis

Schistosomiasis

► ►Tropical Pulmonary

Tropical Pulmonary Eosinophilia Eosinophilia

► ►Cutaneous

Cutaneous Larva Larva Migrans Migrans (CLM) (CLM)

► ►Viscera Larva

Viscera Larva Migrans Migrans (VLM) (VLM)

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Diagnosis Diagnosis

► ► Stool examination

Stool examination

► ► Duodenal fluid

Duodenal fluid

  • Enterotest

Enterotest (HDC Corporation, San Jose, CA) (HDC Corporation, San Jose, CA)

  • Duodenal aspirate via endoscope

Duodenal aspirate via endoscope

► ► Sputum in disseminated infection

Sputum in disseminated infection

► ► Serodiagnosis

Serodiagnosis

  • EIA 85% sensitive

EIA 85% sensitive

  • Cross reaction with

Cross reaction with filaria filaria infections infections

► ► Eosinophilia

Eosinophilia -

  • > 500 /

> 500 / uL uL

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Trichostrongylus Hookworm Strongyloides Rhabdiform Larvae

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Treatment Treatment

Drug Drug Adult dosage Adult dosage Pediatric dosage Pediatric dosage

Ivermectin Ivermectin (Drug of (Drug of choice) choice) 200 200 ug/kg/d ug/kg/d X 1 X 1-

  • 2 days

2 days 200 200 ug/kg/d ug/kg/d X 1 X 1-

  • 2 days

2 days Albendazole Albendazole (IND drug) (IND drug) 400 mg bid X 7 days 400 mg bid X 7 days 400 mg bid X 7 days 400 mg bid X 7 days Thiabendazole Thiabendazole (Alternate) (Alternate) 50 mg/kg/day divided into 50 mg/kg/day divided into q12h doses (maximum 3 q12h doses (maximum 3 gms gms/day) X 2 days /day) X 2 days Consider 5 or more days Consider 5 or more days for disseminated disease for disseminated disease 50 mg/kg/day divided into 50 mg/kg/day divided into q12h doses (maximum 3 q12h doses (maximum 3 gms gms/day) X 2 days /day) X 2 days Consider 5 or more days Consider 5 or more days for disseminated disease for disseminated disease

Medical Letter, August, 2004, Drugs for Parasitic Infections, Nelson’s Pocket Book

  • f Pediatric Antimicrobial Therapy, 15th Edition, Lippincott Williams, Wilkins, 2202-2003
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Adverse Reactions Adverse Reactions

Drug Drug Frequent Frequent Occasional Occasional Rare Rare

Ivermectin Ivermectin Fever, Fever, pruritus pruritus, tender , tender lymphnodes lymphnodes, headache, , headache, joint and bone pain joint and bone pain hypotension hypotension Albendazole Albendazole Diarrhea, abdominal pain Diarrhea, abdominal pain Leukopenia Leukopenia, alopecia, , alopecia, increased serum increased serum transaminase transaminase levels levels Thiabendazole Thiabendazole Nausea, vomiting, Nausea, vomiting, vertigo vertigo Leudopenia Leudopenia, , crystalluria crystalluria, , rash, hallucinations, rash, hallucinations,

  • lfactory disturbance,
  • lfactory disturbance,

erythema erythema multiforme multiforme, , Steven Steven’ ’s Johnson syndrome s Johnson syndrome Shock, tinnitus, Shock, tinnitus, intrahepatic intrahepatic cholestasis cholestasis, , convulsions, convulsions, angioneurotic angioneurotic edema edema

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Control Measures Control Measures

► ► Sanitary disposal of human waste

Sanitary disposal of human waste

► ► Education about the risk of infection through bare

Education about the risk of infection through bare skin in endemic areas skin in endemic areas

► ► Immunodeficient

Immunodeficient patient endemic area consider patient endemic area consider examination of the stool, duodenal fluid and examination of the stool, duodenal fluid and sputum sputum

► ► A patient requiring immunosuppressive therapy

A patient requiring immunosuppressive therapy ( (eg eg cancer chemotherapy) from an endemic area cancer chemotherapy) from an endemic area consider examination of the stool, duodenal fluid consider examination of the stool, duodenal fluid and sputum before treatment with and sputum before treatment with immunosuppressives immunosuppressives