Parasites are microorganisms that live off of other organisms, or hosts, to survive. Some parasites don't affect the host. Others grow, reprodu...
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What is a parasitic infection?
Parasites are organisms that live off other organisms, or
hosts, to survive. Some parasites don’t noticeably affect their hosts. Others
grow, reproduce, or invade organ systems that make their hosts sick, resulting
in a parasitic infection.
Parasitic infections are a big problem in tropical and
subtropical regions of the world. Malaria is one of the
deadliest parasitic diseases. Parasitic infections can also occur in the United
States. Common parasitic infections found in the United States include:
What are the symptoms of parasitic infections?
The symptoms of parasitic infections vary depending on the
organism. For example:
- Trichomoniasis is a sexually
transmitted infection caused by a parasite that often produces no symptoms. In
some cases, it may cause itching, redness, irritation, and an unusual discharge
in your genital area.
- Giardiasis may cause diarrhea,
gas, upset stomach, greasy stools, and dehydration.
- Cryptosporidiosis may cause stomach cramps,
stomach pain, nausea, vomiting, dehydration, weight loss, and fever.
- Toxoplasmosis may cause flu-like
symptoms, including swollen lymph nodes and muscle aches or pains that can last
for over a month.
What causes parasitic infections?
Parasitic infections can be caused by three types of
Protozoa are single-celled organisms that can live and
multiply inside your body. Some infections caused by protozoa include giardiasis.
This is a serious infection that you can contract from drinking water infected
with Giardia protozoa.
Helminths are multi-celled organisms that can live in or
outside of your body. They’re more commonly known as worms. They include flatworms,
tapeworms, thorny-headed worms, and roundworms.
Ectoparasites are multicelled organisms that live on or feed
off your skin. They include some insects and arachnids, such as mosquitos,
fleas, ticks, and mites.
Parasitic infections can be spread in a
number of ways. For example, protozoa and helminths can be spread through
contaminated water, food, waste, soil, and blood. Some can be passed through
sexual contact. Some parasites are spread by insects that act as a vector, or
carrier, of the disease. For example, malaria is caused by parasitic protozoa
that are transmitted by mosquitos when they feed on humans.
Who is at risk of parasitic infections?
Anyone can get a parasitic infection. But some people are at
greater risk than others. You’re more likely to contract a parasitic infection
- have a compromised immune system or are already
sick with another illness
- live or travel in tropical or subtropical
regions of the world
- lack a clean supply of drinking water
- swim in lakes, rivers, or ponds where Giardia
or other parasites are common
- work in childcare, work with soil regularly, or work
in other contexts where you come into contact with feces on a consistent basis
Outdoor cats can come into contact with infected rodents and
birds. This makes their owners more likely to contract toxoplasmosis, a
type of protozoa. Toxoplasmosis can be very harmful for pregnant women
and their developing babies. The infection is spread through cat feces. If you’re
pregnant, it’s important to have someone else clean the litter box daily.
How are parasitic infections diagnosed?
Parasitic infections can be diagnosed in a number of ways.
For example, your doctor might perform or order:
- A blood test
- A fecal exam: In such an exam, a sample of your
stool will be collected and checked for parasites and their eggs.
- An endoscopy or colonoscopy: These tests may be
ordered if the results of a stool exam are inconclusive. While you are sedated,
your doctor will pass a thin flexible tube through your mouth or rectum and into
your digestive system to examine your intestinal tract.
- X-rays, magnetic resonance imaging (MRI), or computerized
axial tomography (CAT): These scans are used to check for signs of lesions or
injury to your organs caused by parasites.
Your doctor may also order tests to check for bacteria or
other things that can cause infections.
How are parasitic infections treated?
Your treatment plan will depend on your specific diagnosis. Typically,
your doctor will prescribe medications. For example, they may prescribe
medications to treat trichomoniasis, giardiasis, or cryptosporidiosis. They
probably won’t prescribe medications for toxoplasmosis if you’re not pregnant
and otherwise healthy, unless you have a severe and prolonged infection.
Your doctor may also recommend other treatments to relieve
your symptoms. For example, many parasitic infections can cause diarrhea, which
often leads to dehydration. Your doctor will likely encourage you to drink
plenty of fluids to replenish those you lose.
How can parasitic infections be prevented?
There are several steps you can take to lower your risk of
contracting a parasitic infection:
- Practice safe sex, using a condom.
- Wash your hands regularly, especially after handling
uncooked food or feces.
- Cook food to its recommended internal temperature.
- Drink clean water, including bottled water when you’re traveling.
- Avoid swallowing water from lakes, streams, or ponds.
- Avoid cat litter and feces when you’re pregnant.
If you suspect you have a parasitic infection, make an
appointment with your doctor. They can help diagnose the cause of your symptoms
and recommend a treatment plan. By getting early treatment, you can help stop
the spread of infection to other people.