5th Semester → CNS Parasitology

Parasitic diseases affecting the nervous system and special senses

🧠 Parasites Affecting the Central Nervous System (CNS)


🖇 I. Mechanisms of CNS Damage

Parasites can affect the CNS through three main mechanisms:
1️⃣ Ectopic Lesion / Embolus: The parasite or its stage migrates and lodges in the CNS.
2️⃣ Inflammatory Reaction: The parasite causes inflammation and tissue damage.
3️⃣ Cystic Lesions: Formation of cysts inside brain tissue, causing pressure and neurological signs.


🟠 II. Parasite Groups Affecting the CNS

1. Trematoda (Flukes):

2. Cestoda (Tapeworms):

3. Nematoda (Roundworms):

4. Protozoa:

5. Arthropods:


🟣 III. Coenurosis Cerebralis (Detailed Focus)

🔹 Definition:
A parasitic disease affecting mainly the brain and CNS of animals, especially sheep.
Human infection is accidental.

🔹 Causative Agent:
Caused by the larval stage (Coenurus cerebralis) of Taenia multiceps (also called Multiceps multiceps).

🔹 Hosts:

🔹 Pathogenesis:

🔹 Symptoms:

🔹 Diagnosis:

🔹 Treatment:

🔹 Prevention & Control:
1️⃣ Regular deworming of dogs.
2️⃣ Proper disposal of dog feces.
3️⃣ Avoid feeding dogs raw or undercooked meat/offal.


🚨 IV. Key Questions Emphasized by the Doctor

  1. Enumerate parasites affecting the CNS (Trematoda, Cestoda, Nematoda, Protozoa, Arthropods).
  2. What are the three mechanisms of CNS damage (ectopic, inflammatory, cystic).
  3. Classify Coenurosis cerebralis correctly → a Cestode disease.
  4. Differentiate hosts of Taenia multiceps → Dog (definitive), Sheep (intermediate).
  5. Explain arthropod effect → usually indirect; direct example is Tick Paralysis Syndrome (temporary).