2 pairs of cutting teeth

New world hookworm

Old world hookworm

2 large and a third smaller pair of teeth

• Migration phase
• Ova in feces
• Soil
• Rhabditiform larvae hatch
• Filariform larvae develop
• Larvae penetrate human skin
• Back to migration phase

Single hyaline shell

2-8 cell developing embryo

Can be confused for decorticated Ascaris

~250 u long

feeding form

large, bulging esophagus

buccal cavity open

~400-600 u long

infective form

small esophagus

buccal vacity enclosed in cuticle

Symptoms

Penetration of skin

-local erythema

-severe itching

Larval lung migration

-allergic symptoms

Adult in small intestine

-ab pain and diarrhea

-iron deficiency anemia

Lab Diagnosis

Microbiology Lab

-ova in feces

Hematology Lab

-Eosiniophilia

-RBC(micro, hypo)

Treatment

-Mebendazole

-Pyrantel pamoate

-Treat anemia w/ Fe

Prevention

-sanitary disposal of human feces

-wear shoes

-vaccine

Diseases

-strongyloidiasis         

-Cochin-China diarrhea

-Threadworm infection

Hosts

-humans

-dogs     

-monkeys

• Migration phase
• Rhabditiform larvae hatch in small intestine
• Feces
• Soil
• Filariform larvae develop
• Larvae penetrate human skin
• Migration phase

• Migration Phase
• Larvae penetrate intestine
• Filariform larvae develop in intestine
• Rhabditiform larvae hatch in s. intestine

Rhabditiform Larva

-buccal cavity long          

-genital primordium small

-tail pointed                   

Filariform Larva

-tail pointed                   

Rhabditiform Larva

-buccal cavity short         

-genital primordium large

-tail blunt                      

Filariform Larva

-tail slit or notched         

Symptoms

Penetration of skin

Migration

Adult in s. intestine

-immediate inflammatory response

-possible anemia

Lab Diagnosis

Rhabditiform larvae in stool

Ova in duodenal intubation speciment

Eosinophilia

Anermia possible

Disease- Trichinosis

Pork

Hosts- humans, hogs, rats, bears

Larvae encyst in muscle

Life Cycle

• Hogs
• Human ingestion
• s. intestine
• larvae invade intestinal mucosa
• adults
• fertilization
• Female deposits larvae into lymphatics
• bloodsteam
• larvae encyst in striated muscle
• Dead end

Symptoms

Intestinal invasion by adults

Migration of larvae

Encystation- muscle degeneration

Trichinosis spiralis

Lab Diagnosis

Muscle biopsy- check for larvae

WBC differential

-eosinophilia            

-general leukocytosis

Serological Tests

-flocculation

-latex agglutination

-indirect fluorescent antibody

-ELISA

Treatment

-steroids

-drugs dont always make it better

Prevention

-cook pork thouroughly

Toxocara canis & catu

Baylisascaris

Dirofilaria immitis

Anisakiasis

Angiostrongylus

• Animal eats embryonated eggs
• Eggs pass through feces and go into soil
• Eggs are ingested
• Larvae hatch in s. intestine and penetrate wall 
• Larvae migrate to all organs via bloodstream
• Pathology

Dog and cat roundworms

found worldwide, especially in children

Stimulates high eosinophilia

Symptoms

fever

ab pain (hepatosplenomegaly)

Eosinophilic granulomas in tissue

-especially liver and lings

Most serious

-blindness

Raccoon roundworm

Found anywhere, especially Midwest

Symptoms

depend upon where larvae migrate

-loss of vision- adults

-encephalitis- children

Heartworm in dogs

Mosquito is vector

Human infections mild

-nodules on arm

-coin lesions in lungs

Infection with marine nematodes

Usually in Japan

Ingestion of raw or undercooked saltwater fish

Larvae burrow into intestine, die, stimulate eosinphilic granulomas

Endemic in SE Asia

Ingestion of infected snails

Larvae travel to brain

-Eosinophilic meningitis

Cutaneous Larva Migrans

Dog and cat hookworm

creeping eruption; dermatitis

Found in tropical and subtropical climates

Tapeworm adults live in intestine of vertebrates

Larvae live in tissue of (in)vertebrates

Adult Morphology

-elongated and flattened

-no intestinal tract

-covered by tegument

• Larvae in intermediate hoste
• Larvae ingested by humans in raw meet
• Small intestine
• Adult Develops
• Ova
• Feces
• Environment
• Ova ingested by intermediate host
• Embryo in intestine 
• Penetration of intestinal wall
• Intramuscular tissue
• Intermediate host

Beef tapeworm

Definitive Host- humans

Intermediate- cattle, herbivoires

Larva: cysticercus larvae

Adult- 4-6 m

~35 u

Radially striated embryophore

Hexacanth embryo

Symptoms

vague- ab pain, diarrhea, weight loss

Feeling of loss of bowel control

Rare- appendicitis

Lab diagnosis

ova in stool

proglottid must be seen to speciate

Prevention

cook beef well

sanitary disposal of feces

Pork tapeworm

Definitive host- humans

Intermediate

-hogs (cysticercus larva)

-humans (cysticercus cellulosae)

Adults

-2-4 m long

-scolex has suckers and hooks

-gravid proglottid

• Human ingest ova in food or water
• Embryo penetrates intestinal mucosa
• Muscle and organs
• Cysticercus larva develops
• Dead end

Symptoms

human definitive host- vague ab pain, diarrhea

Cysticecus cellulosae- neruocysticercosis

Common names

fish tapeworm

broad tapeworm

found in freshwater lakes

definitive hosts

-humans, dogs, cats, bears, etc

Intermediate hosts

-1 freshwater copepod (procercoid larva)

-2 Freshwater fish (pleerocercoid larva)

Longest human tapeworm

-10 m or longer

->3000 proglottids

Symptoms

Vague GI problems

Pernicious anemia

Lab Findings

macro, ovalycytes, hypersegmented PMNs

Dwarf tapeworm

definitive hosts- humans and rodents

Intermediate- none required, fleas and beetles

Adult- 35 mm

Ovum

-45x35 u

-hexacanth embryo

-polar thickenings

-4-8 polar filaments

Definitive hosts- humans and rodents

Intermediate hosts- insects (cysticercoid larva)

Adult is 50 cm

Dog tapeworm

Definitive hosts

-dogs, cats, wild carnivores, sometimes humans

Intermediate

-fleas, lice

Symptoms

Usually no sympotoms

Diagnosis

egg packets in stool

Hydatid cyst disease

Common in sheep and cattle raising

Definitive- dogs, wolves, coyotes, foxes

Intermediate- humans, sheep, cattle, horses, hogs

adult and ova not found in humans

Hydatid cyst

protoscolicies

• Humans ingest ova in soil
• Larvae hatch in intestine
• Larvae penetrate intestine and carried throughout body
• hydatid cysts develop

Primary cyst disease- usually in liver, hepatomegaly

Secondary cyst disease- anywhere in body, more serious than primary

Diagnosis

Eosinophilia

Body scans

Sputum or urine

-protoscolices

Serological tests

Clonorchis sinesnis

Metorchis conjunctus

Fasciola hepatica

Chinese or Oriental Liver Fluke

Far East

Definitive Hosts- humans, fish eating mammals

Intermediate hosts- snail and freshwater fish

• Ingestion of undercooked fish with encysted matacercariae
• Metacercariae crawl into bile ducts
• Adults live in bile ducts
• Ova pass into intestine --> feces

Symptoms

mild or asymptomatic

indigestion, weight loss, hepatomegaly, jaundice, diarrhea, possible anemia

Diangnosis

Ova in feces

North American Liver Fluke

Definitive Hosts- bears, wolves, foxes

Fascioliasis, Liver rot

Sheep liver fluke

Definitive- humans, sheep, cattle, deer, rabbits

Intermediate host- snail, ingested by water plants

• Metacercariae encyst on grass, watercress, bark, soil
• Humans ingest these
• Larvae penetrate intestinal wall and go to liver where adult develop
• Ova pass throug bile ducts to intestine to feces

Symptoms

Early- fever, chills, pain below stomach radiating to back

Later- hepatomegaly, biliary obstruction, liver abscesses, diarrhea, jaundice

Diarrhea

Ova in feces

Fasciolopsis buski

Heterophyes heterophyes

Metagonimus yokagawai

Found in China

Definitive hosts- humans, dogs, rabbits

Intermediate hosts- snail

• Metacercariae on water plants
• Humans ingest these
• Adults develop in small intestine
• Ova in feces

Heterophyes heterophyes

Metagonimus yokagawai

Found in far east, egypt, middle east

Definitive- humans, fish eating mammals

Intermediate- snail and freshwater fish

Heterophyes heterophyes

Metagonimus yokagawai

Symptoms

usually none

heavy infection- ab pain, diarrhea

Diagnosis

ova in feces

Pulmonary Fluke

Paragonimus westermani

oriental lung fluke

far eat

definitive host- humans and other mammals

intermediate host- snail and freshwater crabs

• Metacercariae in crab ingested by humans
• go to intestine and eventually to lungs
• adult lives in lungs
• ova in sputum

Symptoms

blood stained sputum

pleural pain fever

Diagnosis

ova in sputum