Parasites are small organisms that live either in or on another organism, which serves as their host. Some parasites can be microscopic while others are large enough to be seen with the naked eye. When a parasite enters the body, it can cause an infection

What is a parasitic infection?
A parasitic infection is an infection that occurs when a parasite enters a body, makes it a host, and causes the host to become sick. Not all parasites can cause the host damage. The ones that do, however, invade organ systems and can even cause death.
What is a protozoal infection?
A protozoal infection is a parasitic infection caused by organisms formerly classified as part of the Kingdom Protozoa. Protozoan infections affect humans as well as plants, animals, and marine life.
Some protozoan infections include:
- African Sleeping Sickness
- Amoebic dysentery
- Malaria
What are the causes of a parasitic infection?
Parasitic infections can be caused by three different types of organisms:
- Protozoa (as mentioned above)
- Helminths
- Ectoparasites
Parasitic infections can spread in different ways. For instance, protozoa and helminths can be spread through contaminated water, food, waste, soil, or blood. It can also be spread through sexual contact. Other parasites are transmitted through insects that act as carriers of the disease, as in the case of malaria.
What are the symptoms of a parasitic infection?
The signs and symptoms of a parasitic infection greatly depend on the parasite involved. For example:
- Trichomoniasis is a sexually transmitted parasitic infection that typically does not have any symptoms. For those that do experience symptoms, they feel itching, redness, irritation, and unusual discharge in their genital area.
- Giardiasis may cause diarrhea, abdominal cramping and bloating, gas, nausea, fatigue, and weight loss. Not everyone with giardiasis experiences symptoms, which makes it easy to pass the infection from one person to another.
- Cryptosporidiosis patients may experience stomach cramps, stomach pain, nausea, vomiting, dehydration, weight loss, and fever.
- Changas may not cause any symptoms in the first few weeks or months. Once symptoms do arise, these may include mild swelling at the infection site, low fever, body aches and pains, skin rash, headache, nausea and vomiting, diarrhea, swollen lymph nodes.
How to know if you have a parasitic infection
When you have a parasitic infection, you can experience several different symptoms, the most common being:
- Abdominal pain
- Diarrhea
- Nausea or vomiting
- Gas or bloating
- Blood and/or mucus in the stool
- Fever
- Weight loss
- Muscle aches
- Fatigue
- Rashes or an uncontrollable itching sensation
However, the symptoms you may experience if you have a parasitic infection depends on the type of parasite you have, as well as the part of the body that is located. At times, the parasite may have settled in a location where the symptoms may not be immediately visible. For example, some parasites can stay in your intestines and cause lesions, which can only be detected with imaging tests like an X-ray.
If you experience any of these symptoms and have reason to believe you have a parasitic infection, we strongly recommend scheduling an appointment with your healthcare provider.
Treatment for parasitic infections is readily available and can often lead to improvement or resolution of your symptoms.
What are the drugs used for parasitic infections?
Medication and treatment will again vary depending on the parasite causing the infection as well as the symptoms being experienced. Some medications used will specifically target the parasite involved while others may relieve you from the symptoms of the parasitic infection.
Possible drugs are:
- Metronidazole
- Tinidazole
- Albendazole
- Moxidectin