Trichinella spiralis is a parasitic roundworm that causes the disease trichinosis in humans and other animals. The parasite has a complex life cycle, with an adult female worm living in the small intestine and releasing larvae that migrate and encyst in skeletal muscle tissue. Humans typically become infected by eating undercooked pork infected with the larvae. Symptoms vary depending on the stage of infection, but may include diarrhea, vomiting, muscle pain, and breathing difficulty. Diagnosis involves muscle biopsy or blood tests, and treatment primarily consists of anti-inflammatory drugs and the anti-parasitic drug mebendazole.

1. Trichinella spiralis

2. Trichinella spiralis
 Common name: Trichina worm- The Pork worm
 Trichinella spiralis means spira, how this coils up in its host.
 diseases: Trichinosis, Trichiniasis,
 is a zoonotic disease. it is passed between humans and animals.
 Habitat: females in mucosa of small intestinal
 The same animal acts as final and intermediated host
 is most common in Europe, North America, and Asia,
 Infective stage: contaminated meat (muscle) containing encyst larvae (pig)
 Diagnostic stage: larvae encysted in muscle (human)
 Can be fatal if large numbers of cysts form in the heart muscle.

3.  The sperm fertilizes the egg, but the female doesn’t release the
eggs until they have hatched within her uterus, which is usually
within the fifth or sixth day of infection.
 Female worms can produce approximately 1500 newborn
larvae (immature L1) during a life span (4-16 weeks), before
expulsion by the host immune system.
 Viviparous:
Expel active larvae

4. Oviparous: Eggs laid in 1-cell stage
or early cleavage stage.
Ovoviviparous: Eggs laid containing embryo or
larva (L1). Some hatch out prior to passage
in feces.
Viviparous: Expel active larvae

5. Morphology:
Anterior end: slender with small non papilated mouth.
Male:1.5mm
posterior end ventrally curved
with 2 copulatory appendages
Female: 3.5mm single ovary
Posterior end bluntly rounded

7. LARVAE
Measures 80-120 um by 5.6 u at birth
And grows but little until it has entered
A muscle fiber, size 900 um
developed.

8. Female worms deposit larvae into:
 The mucosa of small intestine
 Directly into the lymphatics
 Blood stream.
 The larvae carried to all parts of body,
 but the larvae developing only in striated muscle.

9. Epidemiology
 The disease among humans, rats, and pigs
 Rats and pigs feeding on garbage that includes infected pork
waste, become infected in turn
 Dead or dying infected rats are themselves eaten by pigs
 Raw or poorly cooked pork (sausage) harboring infective larvae
then becomes the vehicle for human infections
 Trichinellosis is a cosmopolitan disease that occurs most
commonly in Europe and the US

12. Pathogenesis:
1--Penetration of the adult females into mucosa
The first symptoms appear between 1- 2 days after ingestion.
The worms migrating in the intestinal epithelium
Inflammation of duodenal and jejunal mucosa:
This causes:
 inflammation,
 nausea,
 vomiting,
 sweating, and diarrhea.

13. 2- The migrating larvae
Ten days after infection the larvae will penetrated the
muscle fibers, carried to all parts of body, This causes
 muscular pain,
 difficulty breathing
 Per orbital edema and conjunctivitis
 heart (myocarditis),
 lungs (pneumonitis),
 brain (encephalitis).
 Can be fatal if large numbers of cysts form in the heart
muscle. heart failure or respiratory or kidney malfunction

14. Diagnosis :
 Muscle biopsy at the encystment stage
 blood test for eosinophilia
 increased levels of creatine phosphokinase CPK,
 Serology test Immunoassays, such as ELISA
 At the diarrheal stage, adult and larvae may be found
in feces

15. Treatment
 Anti-inflammatory drugs. When infected, it is
also suggested that you get a lot of rest to help
give your body time to recover.
 Mebendazole is the drug of choice.