What is trichinosis?
Trichinosis is an infection of the intestine caused by eating food
infected by the parasite Trichinella spiralis.
Trichinosis is rare in the US. However, it is more common among
Southeast Asian immigrants because of some ways they use to
prepare food.
This infection is also called trichinellosis.
How does it occur?
You can get trichinosis by eating raw or inadequately cooked pork,
pork products or wild, meat-eating game, such as undercooked bear.
The parasite is a roundworm whose eggs (cysts) can be in raw meat
or meat that hasn't been cooked enough. New worms emerge from
these eggs in the stomach or intestine and reproduce in your
intestines, causing trichinosis. The incubation period (the time
between when you eat food containing the eggs and the appearance
of the first symptoms of the disease) is generally between 7 and
14 days. However, you might have symptoms as early as a day after
you eat contaminated food.
What are the symptoms?
Trichinosis sometimes has no symptoms. When symptoms do occur,
they come in three stages: the intestinal stage, the muscular
stage, and the convalescent stage.
Symptoms of the intestinal stage occur during the first week. They
include:
- abdominal cramps
- generally not feeling well
- occasional nausea, vomiting, or diarrhea
- fever (rare).
Symptoms of the muscular stage, which occur during the first month
after infection, include:
- fever
- muscle pain and tenderness
- swelling around the eyes
- sweating
- redness of the eyes
- weakness (often severe)
- feeling out of breath
- coughing
- rashes.
During the convalescent stage more severe symptoms may appear,
involving other parts of the body by the second month. Symptoms
may include:
- muscle pains and a general feeling of poor health that last
for several more months
- trouble using some muscles.
How is it diagnosed?
Your healthcare provider will ask about your symptoms, examine
you, and may order tests, such as:
- blood tests
- muscle biopsy to look for the larvae or cysts of the parasite.
If you have a muscle biopsy, first you will receive a local
anesthetic to numb the skin over the muscle of your upper arm or
calf. Your healthcare provider will make a small cut in the skin
and remove a tiny piece of muscle. Your provider will then sew the
skin back together. The muscle will be looked at under a
microscope for signs of trichinosis.
How is it treated?
Most people who have a mild infection get better without
treatment.
For more severe symptoms, your healthcare provider may prescribe
mebendazole or prednisone. Take all your medicine as prescribed.
If you quit taking your medicine before you have taken all of it,
the infection may come back.
If you have a severe infection, you may need to stay at the
hospital. Your healthcare provider may prescribe high doses of
corticosteroids. This medicine helps to control the symptoms.
After 24 to 48 hours of high doses, you may then need lower doses
for several days or weeks at home.
How long will the effects last?
Mild cases of the infection may last 3 to 5 days. In severe cases
the infection may last 1 to 2 months. You may have muscle pains
and feel ill for several more months.
How can I take care of myself?
- If you have diarrhea, you may want to let your bowel rest for
a few hours by drinking only clear liquids such as water, weak
tea, bouillon, apple juice, or sports drinks or oral
rehydrating solutions. You may also drink soft drinks without
caffeine (such as 7 UP) after letting them lose some of their
carbonation (go flat). Make sure you drink often so you do not
become dehydrated. Becoming dehydrated can be very dangerous,
especially for children, older adults, and some people who
have other medical problems. Suck on ice chips or Popsicles if
you feel too nauseated to drink fluids.
- It is OK to keep eating as long as it does not seem to worsen
diarrhea or stomach cramps. Foods that are easiest to digest
are soft starchy foods, such as bananas, cooked cereal, rice,
plain noodles, eggs, gelatin, toast or bread with jelly, and
applesauce. Avoid milk products and caffeine for a few days.
Return to your normal diet after 2 or 3 days, but for several
days avoid fresh fruit (other than bananas), alcohol, greasy
or fatty foods such as cheeseburgers or bacon, highly seasoned
or spicy foods, and most fresh vegetables. Cooked carrots,
potatoes, and squash are fine. If eating seems to worsen
diarrhea, let your bowel rest for a few hours by drinking just
clear liquids.
- If you have cramps or stomach pain, it may help to put a hot
water bottle or electric heating pad on your stomach. Cover
the hot water bottle with a towel or set the heating pad at
low to prevent burns.
- Make sure you take the medicine your healthcare provider
prescribes.
What can be done to help prevent trichinosis?
- Always cook meat, especially pork and pork products, to the
recommended temperature of 170°F (77°C) or higher.
- Freeze pork at 5°F (minus 15°C) for 20 days to kill the
parasite.
- Cook wild game meat thoroughly. Freezing wild game meats, even
for long periods of time, may not kill all worms.
This content is reviewed periodically and is subject to
change as new health information becomes available. The
information is intended to inform and educate and is not a
replacement for medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
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