Parasitology - Lecture 19 & 20 (Swine Trichinella Taenia Protozoa)

Question 1

Discuss Trichinella spiralis

Answer 1

Trichinella spiralis –> Trichinellosis (Trichinois)
- T. spiralis larva in striated skelteal muscle of pigs

Question 2

Discuss the lifecycle and transmission of Trichinella spiralis

Answer 2

• Larvae (L1) in muscle, and adults in intestonme of infected mammals
• Transmitted in undercooked meat –> pigs in domestic cycle, wild pigs, bear, seal, etc
• Zoonotic importance –> typically occurs in outbreak fashionl causes severe disease and death
• Economic importance

Life cycle: L1 ingested –> L2, L3, L4, adult in intestines –> more L1s –> enter bloodstream and disseminate (NOTE that this all occurs in the same host) ———-> then the gastrointestinal phase occurs: L1 (muscle larva) in meat –> excyst in small intestine –> embed in mucosa –> L2, L3, L4, adult (PPP = 5 days) –> newborn larvae ———–> then, the migration phase occurs: newborn larvae –> lymphatics –> circulation –> tissue –> muscle cell ——-> then, the muscle phgase occurs: newborn larvae (L1) in muscle induces cyst formation –> infective muscle larva (L1) –> chornic infection (lasts months to years)

There are NO stages in decal samples for detection

Question 3

NOTE THAT there is missing information on the Sylvatic tranmission cycle (nvolving Trichinella spp) and on the domestic transmission cycle

Answer 3

need to redo these notes

Question 4

Discuss the sources of infection for Trichinella spiralis

Answer 4

• backyard operations or poorly managed swine operations –> dead pigs; cannibalism; tail biting; rodents

Hunted wild aimal meat products

Unusual sources –> horse meat

Question 5

Discuss the ‘pig diagnosis’ of trichinella

Answer 5

Pigs –> some countries inspect all pigs

1) Muscle digestion in acid –>Pepsin and HCL
2) Microscopic inspection of muscle –> tissue squash, histology,
3) ELISA serology –> antibodies develop after about 40 days

Question 6

Discuss the prevention and control of Trichinella

Answer 6

• Education: a) food prearation 2) source
• Managemnt (swine operations)
• Cook 160F for ground pork; or 145 F for porl chops; roasts”

Question 7

Discuss Taenia solium

Answer 7

Swine cestode –> Taenia solium (the pork tapeworm of humans)

Humans: get the larval cysticercus and the adult tapeworm
Pigs: only get the larval cysticercus

• **Zoonotic
• infection with adult tapeworm only happen in humans, as staed above**
• infection with the larval cysticercus stage: cysticercosis in people and pigs; also known as poork measles in pigs

Question 8

Discuss th eklife cycle of Taenia Solium

Answer 8

Adult in human SI –> egg in human feces –> ground –> pig

–> cysticercus in pig muscle –> human –> adult tapeworm

Question 9

Discuss cysticercosis in humans

Answer 9

Source of eggs is the human
1) ingestion of eggs from human feces (human fertilizer on vegetables)
2) Lapse of hygiene of person with adult tapeworm –> eggs on unwashed, feces contaminated hands

Question 10

Discuss the pathology of Taenia soium; also discuss diagnosis of cystercerci in pigs

Answer 10

Pathology:
infection in pigs is NOT a major clinical concern
Cysticerci in people –> pea sized parsitic cysts
- brain, eyes, muscle
- nuerocysticerocsis upon death of cysticercus

Adult tapeworm (only humans)
- intestinal discomfort
- source of eggs

Pigs: see cysterci at slaughter

Prevention: vaccines are available in other countries

Treatment: no treatment