152 Lecture Exam 2

Necator americanus common name

new world hookworm

Necator americanus life cycle

Eggs (feces) → rhabditiform larvae (soil) → filariform larvae → penetrate skin → bloodstream → lungs → trachea → swallowed → adult in intestine

Necator americanus infective stage

J3 larva

Necator americanus transmission

skin penetration

Necator americanus hosts

definitive: human

Necator americanus symptoms

• cutaneous larval migrans

• severe protein deficiency

• blood loss, IDA

Necator americanus diagnostics

eggs in stool

Necator americanus treatment

• mebendazole

• dietary supplements

Necator americanus prevention

shoes

Necator americanus epidemiology

• Brazil/Texas (most common)

• africa, india, china

Necator americanus disease

hookworm infection

Ascaris lumbricoides common name

giant roundworm

Ascaris lumbricoides life cycle

unhatched eggs ingested → larvae hatch → J3 penetrate intestine → migrate to lymphs/venules → molts into J4→ coughed up & swallowed or digested in stomach → adults in intestine

Ascaris lumbricoides infective stage

embryonated egg

Ascaris lumbricoides transmission

fecal-oral

Ascaris lumbricoides location in the body

small intestine

Ascaris lumbricoides hosts

definitive: human

Ascaris lumbricoides symptoms

• malnutrition, abdominal pain

• rashes/eye pain

• asthma

massive infections:

• intestinal blockage

• death

Ascaris lumbricoides diagnostics

egg in stool

Ascaris lumbricoides treatment

mebendazole

Ascaris lumbricoides prevention

• sanitation

• wash produce

• avoid soil exposure

• control human fecal contamination

Ascaris lumbricoides epidemiology

• tropical/subtropical

• US

Ascaris lumbricoides disease

ascariasis

Enterobius vermicularis common name

pinworm

Enterobius vermicularis life cycle

embryonated eggs w/ J3 ingested → eggs hatch in small intestine → larva develops in large intestine → adults attach to mucosa → females migrate from lumen to anus around perianal folds → retroinfection

Enterobius vermicularis infective stage

embryonated egg with J3

Enterobius vermicularis transmission

fecal-oral

Enterobius vermicularis location in the body

colon

Enterobius vermicularis hosts

definitive: human

Enterobius vermicularis symptoms

• asymptomatic

• perianal itching (at night)

• restlessness

• secondary infection from scratching

Enterobius vermicularis diagnostics

• scotch tape test at night

• perianal exam

Enterobius vermicularis treatment

• mebendazole

• sanitizing household

Enterobius vermicularis prevention

• wash bedding

• strict hygiene (keep nails short, morning showers)

Enterobius vermicularis epidemiology

worldwide

Enterobius vermicularis disease

• enterobiasis

• skin damage/secondary infection from itching

Trichinella spiralis common name

pork worm

Trichinella spiralis life cycle

larva released from nurse cells in small intestine → adults invade small intestinal epithelium → females produce juveniles → new larva penetrates tissues to induce host cell transformation

Trichinella spiralis infective stage

encysted J1 larva

Trichinella spiralis transmission

eating undercooked pork

Trichinella spiralis location in the body

muscle tissue

Trichinella spiralis hosts

definitive: pigs, human (dead-end)

Trichinella spiralis symptoms

• nausea, vomiting

• sweats/fever

• diarrhea

• edema

Trichinella spiralis diagnostics

muscle biopsy

Trichinella spiralis treatment

albendazole/mebendazole

Trichinella spiralis prevention

• cook pork thoroughly

• avoid raw game

Trichinella spiralis epidemiology

• mexico

• south america

• africa

• asia

Trichinella spiralis disease

trichinosis

Wuchereria bancrofti common name

filarial worm

Wuchereria bancrofti life cycle

Mosquito injects J3 during blood meal → juveniles migrate to lymph → mature into adults → microfilariae circulate → mosquito ingests → J3 migrate to salivary glands → reinfect

Wuchereria bancrofti infective stage

J3 larva

Wuchereria bancrofti transmission

anopheles/culex mosquito bite

Wuchereria bancrofti location in the body

lymphatics

Wuchereria bancrofti hosts

definitive: human

intermediate: human

Wuchereria bancrofti symptoms

acute phase:

• lymph swelling

• chills/fever

obstructive phase:

• lymphedema (chronic)

Wuchereria bancrofti diagnostics

• blood smear

• imaging

• PCR

• CFA - circulating filarial antigen assay

Wuchereria bancrofti treatment

• diethylcarbamazine (DEC)

• compression bandages

• surgery

Wuchereria bancrofti prevention

mosquito control

Wuchereria bancrofti epidemiology

• central africa

• turkey

• india

• SE asia

• south america

Wuchereria bancrofti disease

lymphatic filariasis/elephantiasis

• driven by host INF response

Dracunculus medinensis common name

guinea worm

Dracunculus medinensis life cycle

human drinks water w/ J3 infected copepods → juveniles released in intestine → penetrate duodenum → adults mature & mate → female migrates to subcutaneous tissue → gravid females migrate to host skin → female emerges in water → releases larvae → J1 must find copepod → penetration of copepods by J1

Dracunculus medinensis transmission

during drought

• copepod explosions

• bathing, washing in infected water

Dracunculus medinensis infective stage

J3 in copepods

Dracunculus medinensis location in the body

skin

Dracunculus medinensis hosts

def: human

int: copepods

Dracunculus medinensis symptoms

• painful blisters

• burning, itching

• edema

• rash

Dracunculus medinensis diagnostics

juveniles in fluid

Dracunculus medinensis treatment

slow extraction

Dracunculus medinensis prevention

• filter water

• vector control

• safe drinking water

• prevent infected indiv. from entering water

• eradication

Dracunculus medinensis epidemiology

Africa

Dracunculus medinensis disease

dracunculiasis

Taenia saginata common name

beef tapeworm

Taenia saginata life cycle

Eggs → cattle ingest → cysticerci in muscle → humans ingest → adult in intestine

Taenia saginata infective stage

cysticercus

Taenia saginata transmission

undercooked beef

Taenia saginata location in the body

intestine

Taenia saginata hosts

• def: human

• int: cattle

Taenia saginata symptoms

• not very pathogenic

• intestinal obstruction, cramps, nausea, allergic rxn, B12 absorption

• difficult to assess as it passes out of anus

Taenia saginata diagnostics

proglottids in stool

Taenia saginata prevention

cook beef thoroughly

Taenia saginata epidemiology

anywhere that beef is consumed

Taenia solium common name

pork tapeworm

Taenia solium life cycle

pigs ingest vegetation contaminated by eggs/gravid proglottids → oncospheres hatch, penetrate intestinal wall & circulate to musculature → oncospheres develop into cysticerci in muscle → humans eat infected/undercooked meat → scolex attaches to intestine

Taenia solium infective stage

cysticercus

Taenia solium transmission

undercooked pork

Taenia solium location in the body

intestine, brain

Taenia solium hosts

def: human

int: pigs, human

Taenia solium symptoms

• depends where

• blindness

• epilepsy

Taenia solium treatment

surgery

Taenia solium prevention

• hygiene

• cook pork

Taenia solium epidemiology

• central & south america

• china

• india

Taenia solium disease

• INF response

• taeniasis

• cysticercosis

Diphyllobothrium latum common name

fish tapeworm

Diphyllobothrium latum life cycle

Eggs pass through uterine pore → water → oncosphere released in copepods → feeds on nutrients → develops procercoid → copepod eaten by fish → procercoid bores through fish intestine to muscle to develop plerocercoid → humans ingest fish → plerocercoid in intestine

Diphyllobothrium latum infective stage

plerocercoid

Diphyllobothrium latum transmission

• eating raw/undercooked fish (more common)

• community sewer into lakes/streams

• US fad of eating raw salmon

Diphyllobothrium latum location in the body

intestine

Diphyllobothrium latum hosts

def: human

int: copepod, broad-eating fish

Diphyllobothrium latum symptoms

• gastrointestinal distress

• fatigue, shortness of breath, lightheaded

• jaundiced skin

• numbness in hands/feet

Diphyllobothrium latum diagnostics

• proglottids in feces

• ventral uterine pore