Cestodes of pigs

• Taenia solium (pork tapeworm)


  • 3 to 5m in length
  • Armed rostellum with two rows of hooks and 4 suckers
  • Uterus has 7 – 12 lateral branches

  
• Hosts

  • Adult: Man
  • Larval stage: Pigs, humans and dogs
• Larval stage

  Cysticercus cellulosae
• Cysticercosis is common in pig-breeding areas
• All suids (pigs) can carry T. solium cysticerci

  
• There may be substitute hosts i.e. small ruminants, dogs and even man
• In canine and human infections, parasite develops in brain and ocular tissue. Generalized cysticercosis is also observed in man
• Clinical signs of adult worms

  • Mild irritation to intestines - slight diarrhea, abdominal pain etc.
• Clinical signs of cysticerci in CNS

  • Locomotor disorder and signs of encephalitis (dizziness, headaches and seizures)
• Clinical signs of cysticerci in eye

  • Blurry vision and or blindness
• Lesions are identical to those of Taenia saginata (beef tapeworm)

  
• Diagnosis methods


  • Clinical diagnosis in living animal if vesicles are present on the tongue
  • Identification of eggs or gravid proglottid in faeces
  • Postmortem diagnosis - two longitudinal incisions in the tongue, full-length section of heart, horizontal slicing of masseter, examination of subscapular connective tissues and muscle surfaces
• Minor infections are difficult to detect
• Other diagnosis methods

  • Examination of pork products for presence of scolex & hooks (artificial digestion in pepsin hydrochloride)
  • CT scan or MRI for neurocysticercosis
  • Serology testing - ELISA, Enzyme-linked immunoelectrotransfer blot (EITB)
  • PCR
  • Demonstration of larva in biopsy samples

  
• Treatment

  • For intestinal infection: Praziquantel or niclosamide
  • For neurocysticercosis: Corticosteroids, anticonvulsants, and sometimes albendazole or praziquantel and/or surgery
• Prevention

  • Treat all Taenia carriers first (mass campaigns required)
  • Give staff preventive anthelmintic treatment periodically
  • Educate sedentary populations to use latrines and proper hygiene especially with food preparation
  • Detect cysticercosis in animals at abattoir and trim less contaminated meat

  
• Methods to destroy cysticerci

  • Cooking of meat (56oC for 5 minutes)
  • Pickling in brine for a month at 25o C
  • Finely mincing meat
  • Freezing: -18oC for 48h; -10oC for 10 days; -15oC for 54 hours (for small carcasses less than 200 kg)