Can animals transmit tapeworms (Taenia) to humans?

Can Animals Give People Tapeworms?

Yes, animals can transmit tapeworms to humans through consumption of undercooked or raw meat containing tapeworm larvae. 1 The most common tapeworms transmitted from animals to humans are Taenia saginata (beef tapeworm) and Taenia solium (pork tapeworm).

Transmission Routes

• Humans acquire Taenia saginata through consumption of undercooked or raw beef containing the larval stage of the tapeworm 1
• Humans acquire Taenia solium through consumption of undercooked or raw pork containing the larval stage of the tapeworm 1
• Fish tapeworms can be transmitted to humans who consume raw or undercooked fish 2
• Humans can also get tapeworms by accidentally ingesting fleas that carry certain tapeworm species, particularly in children 1

Clinical Presentation

• Most tapeworm infections in humans are asymptomatic 1
• When symptoms occur, they may include:
  • Minor abdominal symptoms 1
  • Passage of tapeworm segments (proglottids) in stool or active expulsion through the rectum 1
  • Diarrhea and abdominal cramps (especially with Hymenolepis nana infection) 1
• Special concern: Taenia solium can cause neurocysticercosis if humans ingest eggs (not just larvae), acting as accidental intermediate hosts 3, 4

Diagnosis

• Concentrated stool microscopy for ova or worm segments (proglottids) 1, 2
• Multiple stool specimens should be examined as eggs are eliminated intermittently 1
• For suspected T. solium infection, cysticercosis serology may be warranted 1

Treatment

• For Taenia species (beef or pork tapeworm): Praziquantel 10 mg/kg as a single dose 1, 5
• For Hymenolepis nana (dwarf tapeworm): Praziquantel 25 mg/kg as a single dose 1
• For fish tapeworms: Praziquantel 10 mg/kg as a single dose 2

Prevention

• Cook meat thoroughly:
  • Beef and pork should be cooked to appropriate temperatures to kill tapeworm larvae 2
  • Fish should be cooked to at least 145°F (63°C) or frozen at -4°F (-20°C) for at least 7 days if planning to consume it raw 2
• Practice good hygiene and proper sanitation to prevent fecal-oral transmission 1
• Ensure proper veterinary care for pets to control parasites 1
• In endemic areas, avoid consuming undercooked meat from unknown sources 6

Public Health Considerations

• Taenia solium is of particular concern due to the risk of neurocysticercosis, which can cause seizures and is a leading cause of acquired epilepsy in endemic areas 4
• The risk of infection is highest in areas with inadequate knowledge of infection and hygiene, poor animal husbandry practices, and unsafe management of human and animal waste 6
• Infected individuals should be treated promptly to prevent environmental contamination and further spread 2

Common Pitfalls and Caveats

• Failing to identify the specific tapeworm species can lead to inadequate treatment, especially important for T. solium infections 1
• Not considering tapeworm infection in patients with unexplained gastrointestinal symptoms who consume raw or undercooked meat 1, 7
• Overlooking the need for repeat stool examinations due to intermittent shedding of eggs 1
• Not educating patients about prevention strategies after treatment, leading to reinfection 8