Helminthology Nematodes Nematodes Helminthology Strongyloides - PowerPoint PPT Presentation

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 Subclass Subclass Order Order Superfamily Genus and Species Probable (suborder) prevalence in (suborder) prevalence in man man Secernentea Rhabditida Rhabditoidea Strongyloides stercoralis stercoralis 56 million Secernentea Rhabditida Rhabditoidea Strongyloides 56 million Stronglyloides myoptami myoptami Occasional Stronglyloides Occasional Strongyloides fuelloborni fuelloborni Millions Strongyloides Millions Strongyloides pyocyanis pyocyanis Occasional Strongyloides Occasional

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 (eg eg mental hospitals, prisons, mental hospitals, prisons, temperate climates ( children’ ’s homes) s homes) children ► 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

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 hookworm hookworm vs ► 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 vulvar vulvar constriction constriction post

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

Buccal Space Double Lateral Alae

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 larvae larvae filariform

Life Cycle Life Cycle Intestine Adults mate Eggs produce Penetrates the mucosa 2 molts – 2 weeks Crypts of Lieberkuhn Trachea Life Cycle In bronchial mucosa L1 Rhabditoid Lungs larvae hatch L3 Filariform Larvae Colonic mucosa L3 Filariform Larvae Stool Skin L3 Filariform Larvae Perineal skin Soil L3 Filariform Larvae Warm and moist Soil 24-36 hours Internal Autoinfection L3 Filariform Larvae Free living External Autoinfection rhabditoid adults Male and female – 3-5 days Soil – Direct Development Eggs produced Soil – Indirect Development

Life Cycle Life Cycle Intestine Adults mate Eggs produce Penetrates the mucosa 2 molts – 2 weeks Crypts of Lieberkuhn Trachea Life Cycle In bronchial mucosa L1 Rhabditoid Lungs larvae hatch L3 Filariform Larvae Colonic mucosa L3 Filariform Larvae Stool Skin L3 Filariform Larvae Perineal skin Soil L3 Filariform Larvae Warm and moist Soil 24-36 hours Internal Autoinfection L3 Filariform Larvae Free living External Autoinfection rhabditoid adults Male and female – 3-5 days Soil – Direct Development Eggs produced Soil – Indirect Development

Life Cycle Life Cycle Intestine Adults mate Eggs produce Penetrates the mucosa 2 molts – 2 weeks Crypts of Lieberkuhn Trachea Life Cycle In bronchial mucosa L1 Rhabditoid Lungs larvae hatch L3 Filariform Larvae Colonic mucosa L3 Filariform Larvae Stool Skin L3 Filariform Larvae Perineal skin Soil L3 Filariform Larvae Warm and moist Soil 24-36 hours Internal Autoinfection L3 Filariform Larvae Free living External Autoinfection rhabditoid adults Male and female – 3-5 days Soil – Direct Development Eggs produced Soil – Indirect Development

Life Cycle Life Cycle Intestine Adults mate Eggs produce Penetrates the mucosa 2 molts – 2 weeks Crypts of Lieberkuhn Trachea Life Cycle In bronchial mucosa L1 Rhabditoid Lungs larvae hatch L3 Filariform Larvae Colonic mucosa L3 Filariform Larvae Stool Skin L3 Filariform Larvae Perineal skin Soil L3 Filariform Larvae Warm and moist Soil 24-36 hours Internal Autoinfection L3 Filariform Larvae Free living External Autoinfection rhabditoid adults Male and female – 3-5 days Soil – Direct Development Eggs produced Soil – Indirect Development

Life Cycle Life Cycle Intestine Adults mate Eggs produce Penetrates the mucosa 2 molts – 2 weeks Crypts of Lieberkuhn Trachea Life Cycle In bronchial mucosa L1 Rhabditoid Lungs larvae hatch L3 Filariform Larvae Colonic mucosa L3 Filariform Larvae Stool Skin L3 Filariform Larvae Perineal skin Soil L3 Filariform Larvae Warm and moist Soil 24-36 hours Internal Autoinfection L3 Filariform Larvae Free living External Autoinfection rhabditoid adults Male and female – 3-5 days Soil – Direct Development Eggs produced Soil – Indirect Development

Strongyloides Forked Tail Alveolar lining Eggs Stronglyloides Adult Infiltrate Larva

Life Cycle Life Cycle Intestine Adults mate Eggs produce Penetrates the mucosa 2 molts – 2 weeks Crypts of Lieberkuhn Trachea Life Cycle In bronchial mucosa L1 Rhabditoid Lungs larvae hatch L3 Filariform Larvae Colonic mucosa L3 Filariform Larvae Stool Skin L3 Filariform Larvae Perineal skin Soil L3 Filariform Larvae Warm and moist Soil 24-36 hours Internal Autoinfection L3 Filariform Larvae Free living External Autoinfection rhabditoid adults Male and female – 3-5 days Soil – Direct Development Eggs produced Soil – Indirect Development

Life Cycle Life Cycle Intestine Adults mate Eggs produce Penetrates the mucosa 2 molts – 2 weeks Crypts of Lieberkuhn Trachea Life Cycle In bronchial mucosa L1 Rhabditoid Lungs larvae hatch L3 Filariform Larvae Colonic mucosa L3 Filariform Larvae Stool Skin L3 Filariform Larvae Perineal skin Soil L3 Filariform Larvae Warm and moist Soil 24-36 hours Internal Autoinfection L3 Filariform Larvae Free living External Autoinfection rhabditoid adults Male and female – 3-5 days Soil – Direct Development Eggs produced Soil – Indirect Development

Life Cycle Life Cycle ► All filariform filariform larvae can swim larvae can swim ► All ► Generally strongyloides strongyloides has a lower prevalence than has a lower prevalence than ► Generally hookworm hookworm ► ► Strongyloides L3 L3 filariform filariform larvae are not infectious by the larvae are not infectious by the Strongyloides oral route except for S fuellobourni fuellobourni oral route except for S ► ► 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 period period – – 4 weeks 4 weeks Prepatent ► ► Patent period - - 30 + years 30 + years Patent period

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 perianal perianal area and moves rapidly (10 cm / area and moves rapidly (10 cm / the 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

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 (fat, B12, protein losing (fat, B12, protein losing malabsorption enteropathy) ) enteropathy � Hypereosinophilia � Hypereosinophilia resembling tropical resembling tropical pulmonary eosinophilia eosinophilia (TPE) (TPE) pulmonary � Leukocytosis � Leukocytosis

Larvae