The document summarizes Trichinella spiralis, a parasitic roundworm that can infect humans and cause trichinosis. Key points: - T. spiralis has a complex life cycle involving an intestinal phase in hosts and an encapsulated muscle phase that can persist for decades. - Common symptoms in humans include nausea, vomiting, fever and muscle pain as the larvae migrate and cysts form in muscles. - Transmission occurs through ingesting undercooked meat from infected pigs and other reservoir hosts like bears that harbor the parasite.

2. THE PARASITE'S TAXONOMY IS:
Class : Adenophorea
Subclass : Enoplia
Order : Stichosomida (Trichurata)
Superfamily : Trichocephaloidea
Family : Trichinellidae

3. Trichinella spiralis (green) is the most common member of the
genus and is the primary cause of domestic animal trichinosis.

4. INTRODUCTION…
Trichinosis is caused by ingesting the larvae of
the nematode Trichinella in undercooked, infected tissue.
The roundworm is found in many different carnivorous animals
and scavengers, and can cause serious illness and even death in
humans.
Trichinella has a nearly worldwide distribitution, making it an
incredibly successful parasite.

5. Important terms:
Cyst: A protective wall that forms around the larva.
Host : An organism that harbors a parasite providing food and
shelter.
Reservoir: an animal host that maintains a parasite life cycle in
the wild, and functions as a source of the parasite for humans.
Larva: The young and immature form of the worm.
Nematode: A type of roundworm with a long, unsegmented
body.
Striated muscle: muscles of the skeletal system and of the heart.

6. An infected person can experience nausea, diarrhea,
vomiting, fatigue, fever, and abdominal
discomfort in the first few days after
infection from Contaminated meat.
The incubation period can last between 5 and 45 days,
at which time headaches, fevers, chills, cough, eye
swelling, aching joints, muscle pain, itchy skin,
diarrhea or constipation can set in. Splinter hemorrages
of the fingernails, swelling and muscle pain are caused
by larvae moving through tissue.

7. WEAKNESS AND SORENESS MAY LAST MONTHS AFTER
OTHER SYMPTOMS HAVE SUBSIDED. MANY PEOPLE MAY
NEVER BE DIAGNOSED SINCE MILD OR MODERATE TRICHINOSIS
IS FREQUENTLY MISTAKEN FOR THE FLU OR ANOTHER
COMMON ILLNESS. a HEAVILY INFECTED PATIENT MAY HAVE
PROBLEMS RELATED TO THE CENTRAL NERVOUS SYSTEM, IN
ADDITION TO POSSIBLE HEART AND RESPIRATORY PROBLEMS.
VERY RARELY DO SEVERE CASES CAUSE DEATH.
swollen eyes[ periorbital edema] splinter hamorage

8. Reservoir
Reservoir hosts include bears, pigs, rats, wild cats,
foxes, dogs, wolves, horses, seals and walruses.
Domestic pigs are considered the dominant reservoir
host, but there are many different typical hosts
throughout the world:
Temperate regions : pig, wild boar, horse, dog, bear,
Fox
Tropical regions : wharthog, hyena
Arctic regions : polar bear, walrus, wolf, fox

9. TRANSMISSION
Transmission occurs by ingestion of infected
tissue. Domestic pigs frequently become
infected by ingestion of uncooked garbage or
infected rat carcasses. When humans eat
undercooked or raw meat from pigs and other
reservoir hosts, they too become infected.
Trichinella has no vector.

11. LIFE CYCLE
Larvae are ingested in
raw or undercooked meat
(i.e. pork) and develop into
adults in the small
intestine.
adults are attached to or
buried in the intestinal
mucosa, where they mate. A
female produces ~1,500
living young over a
lifespan of 4 to 16 weeks

12. Larvae enter the lymphatic's and mesenteric
veins, travel throughout the body, and eventually encyst in
striated muscle. A cyst is a kind of protective wall, in this
case created in reaction to the host's immune system.
Larvae may remain viable for up to 25 years in humans!
When viable cysts are ingested by a new host, the cycle
begins again.
There are basically two pathogenic phases in the life cycle.
Infection of the intestine is called the enteral phase and
includes early larval stages in addition to immature and
reproductive adult stages.
Larvae encysted in nurse cells in the
parenteral phase.

13. DIAGNOSISAND TREATMENT
Diagnosis
periorbital edema…
fever…
myositis…
Eosinophilia …
muscle biopsy…
common blood test called
the bentonite flocculation..
ELISA test…

14. Treatment
EARLY TREATMENT
Mebendazole (Vermox) and thiabendazole
(Mintezol) are effective against intestinal larvae
SUPPORTIVE CARE
Aspirin and anti-inflammatory drugs are effective,
but corticosteroids may be necessary in more severe
cases and when myocarditis is involved.

15. PREVENTION
Cook meat, especially pork, bear, walrus,
and wild pig thoroughly .
Freeze pork less than 6 inches thick for 20
days
at 5 degrees F. Freezing is not very effective for
the
meat of arctic animals
 Cook all meat fed to pigs and other animals
and do not allow pigs to eat carcasses of rats.
Clean all tools used to prepare meat.
You CANNOT rely on salting, drying,
smoking or microwaving to kill the encysted
worms.