List the cestades living in intestine
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Here is a thorough summary of all cestodes (tapeworms) that live as adults in the human intestine, drawn from the medical library.
Intestinal Cestodes (Tapeworms)
Cestodes are ribbon-like flatworms. As adults, they attach to the intestinal mucosa via a scolex (head bearing suckers, grooves, or hooks) and absorb nutrients across their body surface. They have no gut of their own. Treatment of choice for all adult intestinal cestodes is praziquantel (niclosamide is an alternative).
1. Taenia saginata - Beef Tapeworm
| Feature | Detail |
|---|---|
| Common name | Beef tapeworm |
| Source of infection | Eating raw/undercooked beef containing cysticerci |
| Size | Several meters long |
| Definitive host | Humans only |
| Intermediate host | Cattle |
| Symptoms | Usually asymptomatic; mild abdominal discomfort, diarrhea |
| Key point | Does NOT cause cysticercosis in humans; eggs are not infective to humans |
| Scolex | 4 suckers, no hooks (unarmed) |
| Proglottid | Gravid uterus has 15-20 primary lateral branches |
2. Taenia solium - Pork Tapeworm
| Feature | Detail |
|---|---|
| Common name | Pork tapeworm |
| Source of infection | Eating raw/undercooked pork containing cysticerci |
| Size | Several meters long |
| Definitive host | Humans (intestinal worm) |
| Intermediate host | Pigs; also humans (if eggs ingested) |
| Symptoms | Usually asymptomatic intestinal infection; but if eggs are ingested, causes cysticercosis (tissue invasion including the brain - neurocysticercosis) |
| Key point | Unique: humans can be BOTH definitive AND intermediate host |
| Scolex | 4 suckers + armed rostellum with hooks |
| Proglottid | Gravid uterus has 7-13 primary lateral branches |
3. Diphyllobothrium latum (now reclassified as Dibothriocephalus latum) - Fish/Broad Tapeworm
| Feature | Detail |
|---|---|
| Common name | Broad fish tapeworm |
| Source of infection | Eating raw/undercooked fish (plerocercoid larvae in fish flesh) |
| Size | Enormous - can exceed 10 meters |
| Definitive host | Humans and other fish-eating mammals |
| Symptoms | Vague abdominal discomfort, weight loss; unique ability to absorb vitamin B12 - can cause pernicious anemia |
| Eggs | Releases >1 million eggs per day; eggs are operculated (unlike Taenia eggs) |
4. Hymenolepis nana (reclassified as Rodentolepis nana) - Dwarf Tapeworm
| Feature | Detail |
|---|---|
| Common name | Dwarf tapeworm |
| Size | ~4 cm (smallest tapeworm infecting humans) |
| Distribution | Worldwide; most common human cestode infection |
| Life cycle | Unique: can complete life cycle directly in humans (no obligate intermediate host required); eggs passed in feces can directly reinfect |
| Internal autoinfection | Eggs can hatch within the gut without leaving - causes heavy infections, especially in children |
| Symptoms | Usually asymptomatic; heavy infections cause intestinal disturbance |
5. Hymenolepis diminuta - Rat Tapeworm
| Feature | Detail |
|---|---|
| Common name | Rat tapeworm |
| Intermediate host | Grain beetles, fleas |
| Transmission | Accidental ingestion of infected arthropods |
| Symptoms | Usually mild or asymptomatic |
| Compared to H. nana | Requires intermediate host (cannot directly self-infect); larger eggs without polar filaments |
6. Dipylidium caninum - Dog Tapeworm
| Feature | Detail |
|---|---|
| Common name | Dog tapeworm |
| Hosts | Dogs, cats; occasionally children |
| Intermediate host | Larval fleas |
| Transmission | Accidental ingestion of infected fleas (e.g., children playing with pets) |
| Proglottid | Distinctive double-pored, pumpkin seed-shaped segments |
| Symptoms | Mostly asymptomatic; children may develop diarrhea and restlessness |
7. Taenia asiaticus - Asian Tapeworm
| Feature | Detail |
|---|---|
| Distribution | Southeast Asia |
| Cycle | Humans - pigs (liver cysticerci) |
| Note | Formerly considered a subspecies of T. saginata; scolex has armed rostellum (like T. solium) but does NOT cause cysticercosis in humans |
Summary Table
| Species | Common Name | Infective Stage | Intermediate Host | Key Distinguishing Feature |
|---|---|---|---|---|
| T. saginata | Beef tapeworm | Cysticercus in beef | Cattle | Unarmed scolex; no cysticercosis in humans |
| T. solium | Pork tapeworm | Cysticercus in pork | Pigs (+ humans) | Armed scolex; causes neurocysticercosis |
| T. asiaticus | Asian tapeworm | Cysticercus in pig liver | Pigs | SE Asia only; no human cysticercosis |
| D. latum | Broad fish tapeworm | Plerocercoid in fish | Copepods + fish | B12 deficiency/pernicious anemia |
| H. nana | Dwarf tapeworm | Eggs (direct) | None required | Smallest; autoinfection; most common |
| H. diminuta | Rat tapeworm | Cysticercoid in beetles | Grain beetles | Needs arthropod host; rat reservoir |
| D. caninum | Dog tapeworm | Cysticercoid in fleas | Larval fleas | Double-pored proglottids; children/pets |
Sources: Jawetz, Melnick & Adelberg's Medical Microbiology 28E; Henry's Clinical Diagnosis and Management by Laboratory Methods; Harrison's Principles of Internal Medicine 22E (2025)
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