[07.33] Food-borne Parasites V2.pdf

Fecal matter

Contamination of food and water with infective stages usually occurs via what source?

Ascaris, Entamoeba histolytica, Giardia

Name three parasites acquired through ingestion of food and water specifically born through fecal contamination.

Taenia saginata, Taenia solium, Diphyllobothrium, Trichinella

Name four food-borne parasites that only become infective once they are inside specific organisms that eventually become foodstuffs.

Beef tapeworm

What is the common name for Taenia saginata?

Pork tapeworm

What is the common name for Taenia solium?

Fish tapeworm

What is the common name for Diphyllobothrium?

Food-borne Trematodes (FBTs)

What is the specific subgroup of food-borne parasitosis caused by flukes?

Opisthorchis, Clonorchis, Fasciola

Name the three liver flukes listed as food-borne trematodes.

Paragonimus

Name the lung fluke listed as a food-borne trematode.

Intestinal flukes

Which category of food-borne trematodes has the highest number of taxonomically diverse species, with over 70?

75 million

What was the estimated extrapolated number of global FBT infections as of 2015-2016?

2 million

How many disability-adjusted life years (DALYs) are attributed to FBTs?

Aquatic and marine snails (mostly freshwater)

What organisms serve as the first intermediate hosts for all food-borne trematodes?

Metacercaria

What is the common infective stage for all food-borne trematodes?

Operculated ova in stools

What is the diagnostic stage for food-borne trematode infections in humans?

Ova size

Besides morphology, what specific characteristic of operculated ova is used to differentiate food-borne trematodes for diagnosis?

Fasciolopsis buski

What is the scientific name of the Giant intestinal fluke?

2-8 cm (20-80 mm)

What is the typical length of an adult Fasciolopsis buski?

Ventral sucker

By what other name is the acetabulum known?

Above the genital pore

Where is the oral sucker located in Fasciolopsis buski?

Cephalic cone

What specific anterior structure is present in Fasciola but absent in Fasciolopsis buski?

Large size with a single operculum

Describe the common appearance of both Fasciolopsis buski and Fasciola ova.

Humans and pigs

Who are the definitive hosts for the Fasciolopsis buski life cycle?

Unembryonated eggs

In what state are Fasciolopsis buski eggs passed out in the feces?

Water

What environment is required for Fasciolopsis buski eggs to become embryonated?

Miracidia

Which stage hatches from embryonated eggs to infect aquatic snails?

Free-swimming cercariae

What stage extrudes from the snail and searches for a second intermediate host?

Water plants

What organisms serve as the second intermediate hosts for Fasciolopsis buski?

Ingestion of water plants containing metacercariae

How do definitive hosts complete the Fasciolopsis buski life cycle?

Duodenum

Where does excystation of Fasciolopsis buski occur in the human body?

Indian lotus (Nelumbo nucifera) and Common lotus (Nymphaea lotus)

Name two types of lotus that act as second intermediate hosts for Fasciolopsis.

Water caltrop (Trapa bicornis)

Which second intermediate host of Fasciolopsis buski is described as looking like a "carabao head"?

Water chestnuts (Eleocharis tuberosa)

Which common grocery item is a second intermediate host for Fasciolopsis buski?

Kangkong or water morning glory (Ipomoea aquatica)

Which common green vegetable is a frequent source of Fasciolopsis buski?

Fasciolopsiasis

What is the clinical name for the disease caused by Fasciolopsis?

Mucoid diarrhea

Inflammation and mild ulceration caused by Fasciolopsis buski results in what clinical manifestation?

Intestinal obstruction

What mechanical complication can occur due to an abundance of 8 cm long adult Fasciolopsis buski worms?

Excretory/secretory proteins of the fluke

What is the theorized cause of "intoxication" symptoms in Fasciola and Fasciolopsis infections?

Spiny intestinal flukes

What is the common name for Echinostoma and Artyfechinostomum?

Collared spines

The anterior oral sucker of Echinostoma is studded with what specific features?

5-12 mm

What is the approximate length of an adult Echinostoma ilocanum or malayanum?

Shorter and more slender

How does the morphology of Echinostoma compare to Fasciolopsis buski?

Vitelline follicles

Which structures in the adult fluke contain the ova?

100 μm (flattened operculum)

What is the typical size and appearance of an Echinostoma ovum?

Aquatic organisms (snails, bivalves, crustaceans, fish, amphibians)

Unlike Fasciola, what comprises the second intermediate hosts of Echinostoma?

Freshwater vegetation

What is NOT a second intermediate host for Echinostoma (unlike Fasciolopsis)?

Other snails

What is a major distinguishing feature of the Echinostoma life cycle regarding its intermediate hosts?

Golden apple snail (Pomacea canaliculata)

Which specific large freshwater snail is a common second intermediate host for Echinostoma?

Golden kuhol (Pila luzonica)

In the Philippines, which snail delicacy from Northern Luzon is the typical second intermediate host of Echinostoma ilocanum?

Viviparidae (River snails/Mystery snails)

In Thailand, which snails sold in wet markets have a 17% prevalence of Echinostoma infection?

Intestinal erosion and ulceration

Epigastric pain in Echinostoma infection is caused by what?

Attachment of the spiny oral sucker to the intestinal mucosa

What causes bloody diarrhea in heavy Echinostoma infections?

Asymptomatic

How are most Echinostoma infections characterized clinically?

Anemia, headache, dizziness, gastric pain

Name four non-specific symptoms of a light-to-moderate Echinostoma infection.

Profuse watery or bloody diarrhea, edema, anorexia

Name three symptoms associated with a heavy Echinostoma infection.

Very small intestinal flukes

By what name did Dr. Migriño coin the group of Heterophyids?

Metagonimus, Haplorchis, Heterophyes

Name the three species of heterophyids discussed in the source.

800 micrometers (less than 1 mm)

What is the approximate length of an adult Metagonimus spp.?

Tip of a pen (microscopic)

What visual comparison is used for the size of Metagonimus?

Fingernail (around 1 cm)

What visual comparison is used for the size of Echinostoma?

Thumb

What visual comparison is used for the size of Fasciola?

Gonotyl

What is the name for the muscular suckers surrounding the genital pores?

Metagonimus spp.

Which heterophyid species has two posterior testes but lacks a gonotyl?

Haplorchis taichui

Which heterophyid species has gonotyls with spines or sclerites and only one testis?

Heterophyes heterophyes

Which heterophyid species has a gonotyl with spines and rodlets surrounding the genital pore?

Muscular and prominent

How is the acetabulum of Heterophyes heterophyes described?

Embryonated eggs

Unlike Fasciolopsis, what state are Heterophyid eggs in when passed in human feces?

Freshwater fish

What is the second intermediate host for Heterophyes heterophyes life cycle?

Freshwater fish (perch, mullets, gobies, Tilapia)

What is the principal mode of human infection for Heterophyids?

Koi pla and Pla rah

Name two Thai fish delicacies documented to harbor intestinal flukes.

Contaminated cooking knives and chopping boards

Besides raw fish, what non-food items can cause human Heterophyid infections?

Mechanical and chemical irritation

What two principal factors are related to the pathogenicity and virulence of intestinal parasites?

Villi and crypts of the small intestines

What is the main habitat of heterophyids in the human body?

Immune status (Immunocompromised vs. Immunocompetent)

What determines whether Heterophyid worms invade deeper layers beyond the mucosa?

Secretory diarrhea

What type of diarrhea is caused by poor intestinal absorption of secretions and destruction of the mucosa in heterophyid disease?

Increased intestinal permeability

What report regarding the intestinal mucosa was noted in experimental mice with heterophyid infection?

Mild and transient

In most cases, how are the clinical manifestations of Metagonimus and other heterophyid infections described?

Lethargy, anorexia, weight loss

Name three common clinical symptoms of heterophyid infection besides pain and diarrhea.

Heart, brain, and spinal cord

Where might Heterophyids erratically migrate in immunocompromised individuals?

Herring worm

What is the common name for anisakids?

Intestinal nematodes (roundworms)

Taxonomically, what type of parasites are anisakids?

Anisakis spp., Pseudoterranova spp., Contracecum spp.

Name the three species included in the anisakid group.

Third-stage (L3) larvae (~1-2 cm long)

What is the specific life stage of anisakids that causes disease in humans?

Marine mammals (dolphins, seals, whales, sea lions)

Who are the definitive hosts for anisakids?

Saltwater

In what environment do anisakid eggs develop into ensheathed, free-swimming L3 larvae?

Crustaceans (shrimp, octopus, crabs)

Who are the primary paratenic hosts for anisakid L3 larvae?

Dead-end hosts

Humans are considered what type of host for anisakids because the larvae do not develop into adults?

Saltwater seafood (Sushi, Sashimi, Ceviche, Mackerel, Squid, Lobster, etc.)

What general type of food is at risk for Anisakis infections?

Peptic ulcer disease (PUD)

Gastric anisakidosis mimics which common clinical condition?

Appendicitis or diverticulitis

Intestinal anisakidosis mimics which common clinical conditions?

Acute abdomen or intestinal obstruction

What are two common misdiagnoses for intestinal anisakidosis?

Granuloma formation

What can occur in recurrent Anisakis infections?

Heat and freezing

Allergens from A. simplex are highly resistant to what two environmental factors?

Chronic exposure

Anisakis-related allergic reactions are a function of what?

23%

According to Ishikra et al. (1983), in what percentage of cases was intestinal anisakidosis correctly diagnosed postoperatively?

Medical (painkillers/symptomatic) vs. Surgical

What is the primary difference in treatment approach between anisakidosis and the conditions it mimics?

Stool exam

What is the primary diagnostic method for Fasciolopsis, Echinostoma, and Heterophyids?

Endoscopy, biopsy, autopsy, or serology

How are anisakids diagnosed given that humans do not produce ova?

Anti-anisakis IgA, IgG, or IgE

What specific serology markers are looked for in intestinal anisakidosis?

Praziquantel

What is the treatment of choice for food-borne trematodes (Fasciolopsis, Echinostoma, Heterophyids)?