Comprehensive Guide to Nematodes, Cestodes, and Filarial Parasites

What is the diagnostic stage for nematodes?

Eggs (larvae for Strongyloides stercoralis)

What is the common name for Enterobius vermicularis?

Pinworm or Seatworm

How is Enterobius vermicularis transmitted?

Ingestion of an infective egg, hand to mouth transport

What is the infective stage of Enterobius vermicularis?

Embryonated eggs

What diagnostic method is used for Enterobius vermicularis?

Cellophane tape of the perianal region

Where do Enterobius vermicularis worms reside in the human body?

Small intestine, large intestine, perianal area

Describe the life cycle of Enterobius vermicularis.

Humans ingest eggs, which hatch in the small intestine; females migrate to the large intestine, lay eggs on perianal skin.

What are common symptoms of Enterobius vermicularis infection?

Asymptomatic cases, perianal itching, irritability, restlessness, nausea, and vulva irritation in girls.

What is the common name for Trichuris trichiura?

Whipworm

How is Trichuris trichiura transmitted?

Hand to mouth ingestion of infective eggs in fecal contamination

What is the infective stage of Trichuris trichiura?

Embryonated egg

What is the diagnostic stage for Trichuris trichiura?

Unembryonated egg found in feces

Where do Trichuris trichiura adults reside?

In the host's large intestine

What are the symptoms of heavy Trichuris trichiura infections?

Ulcerative colitis, inflammatory bowel disease, weight loss, abdominal pain, and possible rectal prolapse.

What is the common name for Ascaris lumbricoides?

Large intestinal roundworm or Ascariasis

How is Ascaris lumbricoides transmitted?

Hand to mouth ingestion of infective eggs with fully developed larvae

What is the diagnostic stage for Ascaris lumbricoides?

Unembryonated egg in feces

Describe the life cycle of Ascaris lumbricoides.

Adult worms in the small intestine produce eggs; juveniles hatch, migrate to lungs, and return to the small intestine.

What are the symptoms associated with Ascaris lumbricoides infection?

Pneumonia, cough, intestinal pain, possible obstruction, and asymptomatic cases.

In which regions is Ascaris lumbricoides prevalent?

Warm countries and areas of poor sanitation.

What is the common name for Necator americanus?

Hookworm Disease

How is Hookworm Disease transmitted?

Infective larvae penetrate the skin, usually through the bottom of the foot.

What is the infective stage of Hookworm Disease?

Filariform larvae found in fecal contaminated soil.

What is the diagnostic stage for Hookworm Disease?

Eggs in feces with a thin shell.

What are the main symptoms during the intestinal phase of Hookworm Disease?

Acute nausea, vomiting, flatulence, diarrhea, and constipation.

What is the life cycle of Necator americanus?

1. Adults attach to the small intestine lining and feed on blood. 2. Females produce eggs passed in feces. 3. Eggs hatch in soil; juveniles develop into infective stage. 4. Infective juveniles penetrate skin, migrate to lungs, are coughed up and swallowed, and mature in the small intestine.

What is the distribution of Necator americanus?

North & South America, Asia (including China and India), and Africa.

What is the common name for Ancylostoma duodenale?

Old World hookworm

What is the morphology of female Ancylostoma duodenale?

9-13 mm, curved dorsally in a hook position, with a mouth present and four teeth.

What are the symptoms of Ancylostoma duodenale infection?

Similar to Necator americanus: severe allergic reactions, sore throat, coughing, headache, nausea, vomiting, flatulence, diarrhea, and constipation.

What is the life cycle of Ancylostoma duodenale?

Similar to Necator americanus: adults attach to the small intestine, produce eggs, hatch in soil, penetrate skin, migrate to lungs, and mature in the small intestine.

What is the common name for Strongyloides stercoralis?

Threadworm or Strongyloidasis

How does Strongyloides stercoralis transmit?

Larvae penetrate exposed skin, usually through the foot.

What is unique about the reproduction of Strongyloides stercoralis?

It is parthenogenic, meaning females can reproduce without males.

What are the symptoms of Strongyloides stercoralis infection?

Abdominal pain, diarrhea, urticaria, weight loss, and possible bronchial verminous pneumonia.

What is the life cycle of Strongyloides stercoralis?

1. Parasitic females embed in the intestinal mucosa. 2. Females produce eggs that hatch in the intestine. 3. Juveniles are passed in feces and can develop into infective or free-living juveniles.

What is the common name for Trichinella spiralis?

Trichina worm, Trichinosis, or Trichinellosis

How is Trichinella spiralis transmitted?

Ingestion of undercooked striated muscle containing encysted larvae in pork, deer, walrus, or bear.

What is the diagnostic stage for Trichinella spiralis?

Encysted larvae in biopsied muscle or serological testing.

What are the symptoms of Trichinella spiralis infection?

Nausea, vomiting, abdominal pain, diarrhea, headache, fever, and possible death during the 4th to 8th week after infection.

What is the life cycle of Trichinella spiralis?

1. Host ingests undercooked muscle with encysted larvae. 2. Larvae are released in the intestine and mature into adults. 3. Females release larvae that encyst in striated muscle.

What is the distribution of Trichinella spiralis?

Worldwide among meat-eating populations, often brought by immigrants from Mexico and Central America.

What is the common name for Dracunculus medinensis?

Guinea Worm

How is Dracunculus medinensis transmitted?

Through human ingestion of infective copepods in drinking water.

What is the typical length of a female Dracunculus medinensis?

Up to 1 meter.

What is the diagnostic stage of Dracunculus medinensis?

Larvae present in water ingested by copepod intermediate host.

What are the main symptoms of Dracunculus medinensis infection?

Allergic reactions, painful blisters, and potential secondary infections.

Where is Dracunculus medinensis commonly found?

Middle East, India, Pakistan, and Africa.

What is the common name for Toxocara canis?

Dog roundworm

How is Toxocara canis transmitted?

Through ingestion of eggs from feces.

What is the infective stage of Toxocara canis?

Embryonated eggs with larvae present.

What are the symptoms of Toxocara canis infection in humans?

Fever, myalgia, weight loss, cough, rashes, and potential ophthalmologic lesions.

What is the common name for Dirofilaria immitis?

Heartworm

How is Dirofilaria immitis transmitted?

Through infected mosquito bites.

What is the diagnostic stage of Dirofilaria immitis?

Long thin white worms present in blood smear.

What are the main symptoms of Dirofilaria immitis infection in canines?

Weakness, chronic cough, vomiting, and labored breathing.

What is the common name for Baylisascaris procyonis?

Raccoon roundworm

How is Baylisascaris procyonis transmitted?

Through ingestion of infective eggs from raccoon feces.

What are the severe symptoms of Baylisascaris procyonis infection?

Ocular, neural, and visceral larvae presence.

What is the common name for Anisakis simplex?

Herring worm

How is Anisakis simplex transmitted?

By consuming raw or undercooked fish.

What are the symptoms of Anisakis simplex infection?

Allergic reactions, abdominal pain, vomiting, and potential intestinal obstructions.

What is the typical length of a female Anisakis simplex?

1-3 cm, with females being longer and thicker than males.

What is the infective stage of Anisakis simplex?

When humans ingest raw fish that has been improperly handled.

What is the location of infection for Dirofilaria immitis?

Heart and pulmonary arteries.

What is the life cycle stage of Toxocara canis after eggs are ingested?

Larvae mature and migrate to the small intestine.

What is the diagnostic stage for Baylisascaris procyonis?

Larvae in body tissue, fluids, or through antibody detection.

What is a common distribution area for Dirofilaria immitis?

Worldwide, mainly in tropical and subtropical areas.

What is the life cycle of Dracunculus medinensis?

Involves ingestion of copepods, migration to subcutaneous tissue, and emergence through the skin.

What is the scientific name of Bancroft's filaria?

Wucheria bancrofti

What disease is caused by Wucheria bancrofti?

Elephantiasis

How is Wucheria bancrofti transmitted?

Larvae enter through bites from mosquitoes into the blood.

What is the morphology of Wucheria bancrofti?

Curved body with a tapered tail; nuclei do not extend to the tip of the tail and appear as a sheath.

What is the diagnostic stage for Wucheria bancrofti?

Microfilariae in blood

What are the acute and chronic symptoms of Wucheria bancrofti infection?

Acute: fever and lymphangitis; Chronic: elephantiasis due to obstruction of lymphatics.

What is the scientific name of Brugia malayi?

Brugia malayi

What disease is associated with Brugia malayi?

Malayan filariasis

How is Brugia malayi transmitted?

Injection of microfilariae via arthropod intermediate hosts like Mansonia or Anopheles mosquitoes.

What is the morphology of Brugia malayi?

Usually tightly coiled with a tapered tail; nuclei do not extend to the tip of the tail and appear as a sheath.

What are the symptoms of Brugia malayi infection?

Acute: fever and lymphangitis; Chronic: elephantiasis due to obstruction of lymphatics.

What is the scientific name of the Eyeworm?

Loa loa

What disease is caused by Loa loa?

Eyeworm

How is Loa loa transmitted?

Adult filariae in human subcutaneous tissue produce living embryos that migrate into lymphatics, blood, or skin.

What is the morphology of Loa loa?

Tapered tail, often coiled; nuclei extend to the end of the tail.

What are the symptoms of Loa loa infection?

Localized subcutaneous edema around the eye, proteinuria, and endomyocardial fibrosis.

What is the scientific name of the causative agent of river blindness?

Onchocerca volvulus

What disease is caused by Onchocerca volvulus?

River blindness or blinding filaria

How is Onchocerca volvulus transmitted?

Adult filariae in human subcutaneous tissue produce living embryos that migrate to lymphatics, blood, or skin.

What is the morphology of Onchocerca volvulus?

Tapered tail sharply angled with no sheath present; nuclei are absent.

What are the symptoms of Onchocerca volvulus infection?

Fibrotic nodules on the skin, pigmented rash, and potential blindness.

What is the scientific name of the dwarf tapeworm?

Hymenolepis nana

How is Hymenolepis nana transmitted?

Eggs ingested by humans in contaminated food, water, or through hand-to-mouth contact.

What is the morphology of Hymenolepis nana eggs?

Oval eggs, subspherical 40-60 um x 30-50 um, with polar filaments.

What are the symptoms of Hymenolepis nana infection?

Light infections can be asymptomatic; heavy infections may cause intestinal enteritis, abdominal pain, diarrhea, headache, and dizziness.

What is the scientific name of the beef tapeworm?

Taenia saginata

How is Taenia saginata transmitted?

Cysticercus bovis eaten by humans in undercooked beef.

What is the morphology of Taenia saginata?

Proglottids have 15-20 branches; eggs are rounded or subspherical with a thick striated brown shell.

What is the scientific name for the Pork tapeworm?

Taenia solium

What disease is caused by Taenia solium?

Taeniasis

How is Taenia solium transmitted to humans?

By ingesting cysticercus cellulosae larva in undercooked pork