Parasitic Helminths

Clonorchis Sinensis (oriental liver fluke)

• Definitive and Intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

Definitive host: human

Intermediate host: freshwater fish and snail

• How does the infection happen in humans?

  • Eating raw or undercooked fish that has been infected

• How do we diagnosis the infection?

  • Presence of eggs in the stool

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Egg: operculum

  • Adult: testes and uterus in one

• Name the diseases caused by the above organisms

  • Clonorchiasis (liver disease)

• Symptoms

  • Abdominal pain

  • Inflamed bile ducts

  • Liver damage

  • Bile duct cancer (extreme cases)

Chlonorchis sinensis egg

Operculum + small knob

Reminds me of an urn

Clonor sounds like urn

Schistosoma mansoni

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• definitive host: humans

• Intermediate host: freshwater snail

• How does the infection happen in humans?

  • Infected human urinates/poops in the water

  • Uninfected human enters water that has been contaminated with infected urine and feces.

  • Larvae penetrates unbroken skin, traveling into the mesenteric veins (gut) or urinary tract (in some species)

• How do we diagnosis the infection?

  • Presence of eggs in the feces or urine (some species only)

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Egg: distinct lateral spine

  • Adult female: thinner, fits into male groove

  • Adult male: shorter, wider, groove where female can lie inside of

• Name the diseases caused by the above organisms.

  • Schistosomiasis

• Symptoms

  • Bloody urine

  • Painful/difficulty urinating

  • Abdominal pain

  • Diarrhea

Schistosoma mansoni female and male adult

Schistosoma mansoni egg

Lateral spine

Mnemonic: S in Schistosoma = Spine

dipylidium caninum

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host

  • Dog or cat

  • Humans (children usually)

• Intermediate host?

  • Cat or dog flea

• How does the infection happen in humans?

  • Accidental ingestion of flea contaminated with the larval stage of the parasitic helminth

• How do we diagnosis the infection?

  • Presence of proglottids or egg packets in the stool

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Eggs: clusters of eggs (egg packets)

• Name the diseases caused by the above organisms.

  • Dipylidiasis

• Symptoms

  • Abdominal pain

  • Indigestion

  • Loss of appetite

Rmbr: its a dog tapeworm and tapeworms have segments (proglottids) containing egg packets

Dipylidium caninum egg packets

Echinococcus granulosus

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host?

  • Domestic and wild carnivores (eg: wolves, dogs, dingos)

• intermediate host?

  • Herbivorous mammals (Eg: sheep, elk)

  • Humans (accidental, dead end intermediate hosts)

• How does the infection happen in humans?

  • Fecal oral route (accidentally ingesting food contaminated with eggs or fingers contaminated with eggs, which come from the feces of wild/domestic carnivores)

• How do we diagnosis the infection?

  • Imaging techniques (MRI, CT Scan) to detect hydatid cysts

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Hydatid cyst

• Name the diseases caused by the above organisms.

  • Hydatid disease

• Symptoms

  • Cysts form in liver + lungs

  • Cough

  • Shortness of breath

  • Chest pain

  • Abdominal pain

  • Pressure in liver/lungs

Echinococcus granulosus adult

Looks like a c*ck

Echinococcus granulosus hydatid cyst w protoscolices

Taenia spp.

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host?

  • Humans

• intermediate host?

  • Pork or cattle

• How does the infection happen in humans?

  • Eating raw or undercooked pork or cattle that has been infected

• How do we diagnosis the infection?

  • Presence of eggs or proglottids in the stool (bc rmbr its a tapeworm)

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Scolex

    • Suckers

    • Hooklets

  • Proglottids

  • Eggs

    • Striated outer shell

• Name the diseases caused by the above organisms.

  • Taeniasis

  • Cysticercosis

    • Infection with the larval stage of the worm in the brain, eyes, and muscles. Direct ingestion of Taenia solium eggs

• Symptoms

  • Abdominal pain

  • Weight loss (hooks onto duodenum of small intestine, where most digestion occurs. Rmbr: tapeworm diet)

  • Cysticercosis: seizures, muscle/eye damage, mimics brain tumor symptoms

• Pork tapeworm;

  • Taenia solium

• Beef tapeworm:

  • Taenia saginata

Taenia solium scolex

Taenia solium proglottids

Taenia solium eggs

SOL= looks like sun rays aka striations

Ascaris lumbricoides

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host

  • Humans

• intermediate host?

  • None

• How does the infection happen in humans?

  • Ingestion of contaminated food or soil (contaminated w/human feces)

  • Eg: consuming unwashed/unpeeled fruits/veggies, hands/fingers w/dirt into mouth

  • Pathway: mouth, intestines, bronchial tree (lungs), throat, swallow, intestines, poop.

• How do we diagnosis the infection?

  • Presence of eggs in the stool

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Eggs: mammillations (Edge of the egg has scalloped/wavy edges)

• Name the diseases caused by the above organisms.

  • Ascariasis and ascaris pneumonia

• Symptoms

  • Cough

  • Abdominal discomfort

rmbr: its a human roundworm (Roundworms r found in soil)

Mnemonic: ASpoonful of soil. Lumb sounds like lung so it infects the lungs

Ascaris lumbricoides egg

Mnemonic: ASC = A SCalloped edge

Enterobius vermicularis

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host:

  • Humans

• intermediate host?

  • None

• How does the infection happen in humans?

  • Ingestion of eggs (from self-contamination or contaminated clothing, bedding, fingers, etc.)

• How do we diagnosis the infection?

  • Presence of eggs collected from the perianal region using cellophane tape

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Egg: oval shaped with one flattened side and one rounded side.

  • Adult female: straight, pointed tail (that’s why they’re called pinworm)

• Name the diseases caused by the above organisms.

  • Enterobiasis (pinworm infection)

• Symptoms

  • Itchy rectum (Worm lays eggs on perianal region)

Enterobius vermicularis adult

Enterobius vermicularis eggs

Ancylostoma duodenale (Necator americanus)

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host?

  • Humans

• intermediate host?

  • None

• How does the infection happen in humans?

  • Humans become infected by walking barefoot on contaminated soil, where infectious larvae are present

  • Larvae penetrate skin, enter circulation, travel to lungs, bronchial tree, throat, intestines (hook onto intestines)

• How do we diagnosis the infection?

  • Presence of eggs in the stool sample

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Adult: small hooks

• Name the diseases caused by the above organisms.

  • Hookworm disease

• Symptoms

  • Iron-deficiency Anemia

  • Fatigue

  • Anorexia

• Mnemonic: duo = do not walk barefoot

Ancylostoma duodenale

No scolex

Small hooks that look like fangs

Strongyloides stercoralis

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host?

  • Humans

• intermediate host?

  • None

• How does the infection happen in humans?

  • Also walking barefoot in contaminated soil

  • Infective filariform larvae penetrate skin —> blood—> lungs —> swallowed —> intestines

  • Worms mature into adults in intestines and prod eggs that hatch to make rhabditiform larvae

  • The larvae are either

    • passed through feces or

    • can cause auto infection (stay in body and become filariform larvae - infectious)

• How do we diagnosis the infection?

  • Presence of rhabditiform larvae in the stool, duodenal fluid, or biopsy specimens.

  • Not eggs bc eggs hatch in intestines —> rhabditiform

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Rhabditiform larvae

• Name the diseases caused by the above organisms.

  • Strongylodiasis

• Symptoms

  • Itchy rash at site of entry (often feet)

  • Lung- shortness of breath, cough

  • Intestines - abdominal pain

Mnemonic : RALIS Strong

RhAbditiform Larvae IS Strong

STE= STEp in soil

Strongyloides stercoralis rhabditiform larvae

Wuchereria bancrofti

• Definitive and intermediate host?

• How does the infection happen in humans?

• How do we diagnosis the infection?

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

• Name the diseases caused by the above organisms.

• Symptoms

• Definitive host

  • Humans

• intermediate host?

  • Mosquitoes

• How does the infection happen in humans?

  • Mosquito bites an infected human and ingests microfilariae.

  • Inside the mosquito, microfilariae develop into infective larvae.

  • Infective larvae enter a new human host via mosquito bite.

  • Larvae migrate to lymphatic vessels, mature into adult worms, and reproduce, releasing microfilariae into the bloodstream to continue the cycle.

  • Adults cause blockage of lymph vessels, leading to lymphatic filariasis (elephantiasis).

  • Summary: getting bit by a mosquito infected with larval stage of parasitic worm

• How do we diagnosis the infection?

  • Blood tests to detect microfilariae in peripheral blood — best collected at night when microfilariae circulate.

  • Clinical symptoms (swelling, elephantiasis).

• Is there any identifying characteristics for the egg, larvae or adult of each organism?

  • Microfilariae

• Name the diseases caused by the above organisms.

  • Lymphatic filariasis- causes blockages of lymph vessels, leading to elephantiasis

• Symptoms

  • Elephantiasis (swelling of limbs, genitalia)

  • Lymph node swelling

Mnemonic: we WUSCH mosquitos away

RIA= microfilaRIAe

Wuchereria bancrofti microfilaria