Chagas disease

Subject: Chagas disease Thu Jan 20, 2011 12:35 pm

Chagas disease
Filed under: Infectious Diseases
Chagas (SHA-gus) disease is an inflammatory, infectious condition caused
by a parasite found in the feces of the reduviid bug. Also called
American trypanosomiasis, Chagas disease can infect anyone, but is
diagnosed most often in children.

Chagas disease is common in South America, Central America and Mexico,
the primary home of the reduviid bug. In recent years, rare cases of
Chagas disease have been found in the southern United States, as well.

Left untreated, Chagas disease can cause serious heart and digestive
problems. Treatment of Chagas disease focuses on killing the parasite
and managing signs and symptoms. You can take steps to prevent the
infection.

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Symptoms

Chagas disease occurs in three phases: acute, intermediate and chronic.
Symptoms in the acute and chronic phases can range from mild to severe,
although many people don't experience symptoms until the chronic stage.
In the intermediate stage, which occurs eight to 10 weeks after the
infection, there are no signs or symptoms.

Acute phase
The acute phase of Chagas disease, which lasts for weeks or months, may
be symptom-free. When signs and symptoms do occur, they are usually mild
and may include:

* Swelling at the infection site
* Fever
* Fatigue
* Rash
* Body aches
* Headache
* Loss of appetite
* Nausea, diarrhea or vomiting
* Swollen glands
* Enlargement of your liver or spleen

Signs and symptoms that develop during the acute phase usually go away
on their own. However, if untreated, the infection persists and advances
to the chronic phase.

Chronic phase
Signs and symptoms of the chronic phase of Chagas disease may occur 10
to 20 years after initial infection, or they may never occur. In severe
cases, however, Chagas disease signs and symptoms may include:

* Irregular heartbeat
* Inflamed, enlarged heart (cardiomyopathy)
* Congestive heart failure
* Sudden cardiac arrest
* Difficulty swallowing due to enlarged esophagus
* Abdominal pain or constipation due to enlarged colon

When to see a doctor
See your doctor if you live in or have traveled to an area at risk of
Chagas disease and you have signs and symptoms of the condition, such as
swelling at the infection site, fever, fatigue, body aches, rash and
nausea.

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Causes

The cause of Chagas disease is the parasite Trypanosoma cruzi.

T. cruzi is transmitted to humans by various species of bloodsucking
insects known as triatomine insects or reduviid bugs. Also called
"kissing bugs" because of their tendency to feed on faces, these insects
become infected by T. cruzi when they ingest blood from an animal
already infected with the parasite.

Reduviid bugs live primarily in mud, thatch or adobe huts in Mexico,
South America and Central America. They hide in crevices in the walls or
roof during the day, then come out at night — often feeding on sleeping
humans.

When infected reduviid bugs bite humans, they defecate, passing the T.
cruzi parasites in their feces, which irritates the skin of the infected
person. The parasites can then enter your body through your eyes,
mouth, a cut or scratch, or the wound from the reduviid bug's bite.
Scratching or rubbing the bite site can help the parasites enter your
body. Once in your body, the parasites multiply and spread.

You may also become infected by:

* Eating uncooked food contaminated with feces from infected reduviid bugs
* Being born to a woman infected with T. cruzi
* Having a blood transfusion containing infected blood
* Getting an organ transplant containing infected blood
* Working in a laboratory where there's an accidental
* Spending time in a forest that houses infected wild animals, such as raccoons and opossums
* Being with an infected pet

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Risk factors

The following factors may increase your risk of getting Chagas disease:

* Living in impoverished rural areas of Central America, South America and Mexico
* Living in a residence that contains reduviid bugs
* Receiving a blood transfusion or organ transplant from a person who carries the infection

It's rare for travelers to the at-risk areas in South America, Central America and Mexico to contract Chagas disease.

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Complications

If Chagas disease progresses to the chronic phase, serious heart or digestive complications may occur. These may include:

* Heart failure. Heart failure occurs when your heart becomes so
weak or stiff it can't pump enough blood to meet your body's needs.
* Enlargement of the esophagus (megaesophagus). This rare condition
is caused by the abnormal widening (dilation) of your esophagus, which
can result in difficulty with swallowing and digestion.
* Enlargement of the colon (megacolon). Megacolon occurs when your
colon becomes abnormally dilated, causing abdominal pain, distension and
severe constipation.

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Preparing for your appointment

You're likely to start by first seeing your family doctor or a general
practitioner. Depending on his or her findings, your doctor may refer
you to an infectious disease specialist.

It's a good idea to be well prepared for your appointment. Here's some
information to help you get ready for your appointment, and what to
expect from your doctor.

What you can do

* Be aware of any pre-appointment restrictions. At the time you make
the appointment, be sure to ask if there's anything you need to do in
advance.
* Write down any symptoms you're experiencing, including any that
may seem unrelated to the reason for which you scheduled the
appointment.
* Write down key personal information, including travel to other countries, major stresses or recent life changes.
* Make a list of all medications, vitamins and supplements that you're taking.
* Take a family member or friend along, if possible. Someone who
accompanies you may remember something that you missed or forgot.
* Write down questions to ask your doctor.

Preparing a list of questions will help you make the most of your time
with your doctor. List your questions from most important to least
important. For Chagas disease, some basic questions to ask your doctor
include:

* What is likely causing my symptoms or condition?
* Are there other possible causes for my symptoms or condition?
* What kinds of tests do I need?
* Is my condition likely temporary or chronic?
* What is the best course of action?
* What are the alternatives to the primary approach that you're suggesting?
* I have these other health conditions. How can I best manage them together?
* Is my family likely to be infected?
* Should I see a specialist?
* Are there any brochures or other printed material that I can take home with me? What Web sites do you recommend visiting?

Don't hesitate to ask other questions during your appointment anytime you don't understand something.

What to expect from your doctor
Your doctor is likely to ask you a number of questions, including:

* When did you first begin experiencing symptoms?
* Have your symptoms been continuous or occasional?
* How severe are your symptoms?
* What, if anything, seems to improve your symptoms?
* What, if anything, appears to worsen your symptoms?
* Have you been anywhere, such as Mexico, where the reduviid bug is common?

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Tests and diagnosis

Your doctor will conduct a physical exam, asking about your symptoms and any factors that put you at risk of Chagas disease.

If you have the signs and symptoms of Chagas disease, blood tests can
confirm the presence of the T. cruzi parasite or the proteins that your
immune system creates (antibodies) to fight the parasite in your blood.

If you're diagnosed with Chagas disease, you'll likely undergo
additional tests to determine whether the disease has entered the
chronic phase and caused heart or digestive complications. These tests
may include:

* Electrocardiogram, a procedure that records the electrical activity of your heart
* Abdominal X-ray, a procedure that uses radiation to capture images of your stomach, intestines and colon
* Upper endoscopy, a procedure in which you swallow a thin, lighted
tube (endoscope) that transmits images of your esophagus onto a screen

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Treatments and drugs

Treatment for Chagas disease focuses on killing the parasite and managing signs and symptoms.

During the acute phase of Chagas disease, the prescription medications
benznidazole and nifurtimox may be of benefit. Both drugs are available
in the regions most affected by Chagas disease. In the United States,
however, the drugs can be obtained only through the Centers for Disease
Control and Prevention.

Once Chagas disease reaches the chronic phase, medications aren't
effective for curing the disease. Instead, treatment depends on the
specific signs and symptoms:

* Heart-related complications. Treatment may include medications, a
pacemaker or other devices to regulate your heart rhythm, surgery, or
even heart transplant.
* Digestive-related complications. Treatment may include diet
modification, medications, corticosteroids or, in severe cases, surgery.

Prevention

If you live in a high-risk area for Chagas disease, these steps can help you prevent infection:

* Avoid sleeping in a mud, thatch or adobe house, if possible. These
types of residences are more likely to harbor reduviid bugs.
* Use insecticide-soaked netting over your bed when sleeping in thatch, mud or adobe houses.
* Use insecticides to remove insects from your residence.

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