1. Taenia Solium Cysticercosis
Dr I Burger
Dept Neurology
IALCH

2. Introduction Human tapeworm (Cestode) Complex two-host life cycle
Taenia Solium
Complex two-host life cycle
Infection causes two diseases:
Relationship adult tapeworm and cysticerosis only established in 1855
Kuchenmaister fed infected pork to condemned prisoners and recovered the worms from their intestines
Taeniasis
[Definitive hosts: humans]
Cysticercosis
[Intermediate hosts:Pigs & humans]

3. Epidemiology

4. Life Cycle

5. Biology and life cycle
Cycle starts when humans ingest undercooked pork meat that contains cysticeri
Cysticerci represent the larvae of the tapeworm
The larvae evaginate in the small intestine and the scolex attaches to the mucosa and starts forming segments (proglottids)

6. GARCIA et al LANCET NEUROLOGY OCTOBER 2005;4:653-661

7. GARCIA et al LANCET NEUROLOGY OCTOBER 2005;4:653-661

8. Biology and life cycle
The worm attaches to the mucosa of the small intestine by means of hooks and suckers located in the scolex (head)
It feeds on nutrients from ingested food
Causes minimal inflammation at the implantations site

9. Biology and life cycle
It has head (scolex), neck, strobila (body) that consists of hundreds of segments (proglottids)
After about 2 months gravid distal proglottids begin the detach from the worm and is excreted in the faeces
Each proglottid contain 50 – 60 thousand fertile eggs

10. Biology and life cycle
Hooks
Suckers
Scolex
Neck
Proglottids

12. Biology and life cycle

13. Biology and life cycle
Eggs are ingested by either humans or pigs that are exposed to human faeces (faecal-oral)
Many humans (15-25%) infect themselves
Other infections from household member
Eggs contain an embryo that is called an oncosphere
Action of gastric acid and intestinal fluids (bile salts) release the embryos from the eggs

14. Biology and life cycle
Oncospheres then actively cross the bowel wall, enter the bloods stream and migrate to internal organs
Predilection for muscle, brain and eyes
Within organs they encyst reaching their definitive size of 1cm within 2 months
Cells within the cyst differentiate into scolex – mature Taenia Solium larva

16. Biology and life cycle
It will remain alive and viable for a variable period of time – during this phase there is no immune response to the parasite
After some time it starts to degenerate resulting in inflammation finally leaving only a calcified scar
Vesicular, Colloidal, Granular, Calcific stages

17. Biology and life cycle
Undercooked pork is then ingested, larvae is released in the intestinal tract
Scolex is released and attaches to the bowel wall
Adult tapeworm then develops from behind scolex

18. Biology and life cycle
GARCIA et al LANCET NEUROLOGY OCTOBER 2005;4:

19. Clinical manifestations
Taeniasis (tape worm infestation)
Minimal symptoms or none at all
In severe infestations;
Malnutrition
Abdominal discomfort
Occasionally patients may notice the passage of proglottids within their stools

20. Clinical manifestations
Cysticercosis
Divided into extraneural
Skin:
Small painless mobile nodules
Muscle:
Asymptomatic or pseudohypertrophy
Eyes:
Asymptomatic or variable degrees of visual loss
Neurocysticercosis

24. Neurocysticercosis
After entering the CNS the cysticerci are viable and elicit very little inflammation
It can remain like this for long time protected by the Blood-Brain-Barrier
After variable amount of time the cyst starts to degenerate resulting in inflammation

25. Neurocysticercosis
Cysts cause disease by acting as mass lesions, blocking CSF flow
MOST of the symptoms direct result of the host inflammatory response due to cyst degeneration
Therefore clinical manifestations depend on:
Number
Location
Size
Hosts immune response to the cysts

26. Neurocysticercosis Epilepsy Headaches Paraparesis Psychiatric Strokes
Dementia

27. Neurocysticercosis Diagnosis X-rays of the muscles
Imaging of the brain and spinal cord (CT & MRI)
Serology
CSF examination

28. Brain imaging: Colloidal Vesicular Calcified Granular
Garcia, H. H. et al. N Engl J Med 2004;350:

34. Treatment
The decision if and how to treat patients with neurocysticercosis is complex and controversial
When a decision is made to treat it involves three different interventions
Anti-parasitic agent (albendazole or praziquantel)
Anti-inflammatory agent (prednisone)
Surgery (shunting or surgical removal of a cyst)

35. Treatment guidelines
GARCIA et al LANCET NEUROLOGY OCTOBER 2005;4:

36. Epidemiological control

37. Epidemiological control
Health education
Improved hygiene and sanitation
Treatment of Taeniasis
Improved pig husbandry
Effective disposal of pig carcasses
Vaccination of pigs
Chemotherapy for infected swine

38. Courtesy – FOYACA SIBAT