Parasites that affect humans are a common cause of illness, particularly in underdeveloped countries. These parasites may attack the body by biting or stinging the skin, or they may be ingested through consumption of contaminated water or food. Though some infected individuals may not experience any problems when infected, there are symptoms of human parasite infection.
Intestinal Symptoms
Intestinal parasites can affect the levels of sodium and chloride in your body, which can cause your stools to become loose and watery. In some instances, your stools may also contain blood and mucus---a condition called dysentery.
Parasites in the intestines can produce inflammation within the intestinal wall, which may leave you feeling nauseous. Some parasites can produce toxic substances that may induce vomiting.
They can cause inflammation in the upper small intestine, resulting in the production of gas. This excess gas may leave you feeling uncomfortable and bloated.
Intestinal parasites can inflame or irritate the intestinal tract, causing pain or tenderness within the stomach or abdomen. Related symptoms, such as nausea or bloating, may also lead to stomach or abdominal pain.
Skin Symptoms
Some parasites prefer to reside in the epidermis---the outside layer of skin covering your body---rather than the intestine. Skin parasites, such as lice, fleas, bedbugs, mites and ticks, are common amongst young children, individuals who spend time outdoors or those with poor hygiene. Skin parasites may infect the skin by biting, stinging or burrowing beneath it. Individuals who have been exposed to to skin parasites may experience rash, irritation, swelling, itching, red bumps, welts and other skin lesions.
Constitutional Symptoms
Parasites can also cause additional symptoms throughout your body---a term called constitutional symptoms. Any type of parasite may cause one or more of the following symptoms:
Joint/muscle aches
Some parasites can live deep within your muscles or within the fluid that surrounds your joints. These parasites can cause muscle or joint inflammation, leading to an achy feeling throughout your body.
Restlessness/anxiety
Some parasites can produce waste or toxins that infect your central nervous system. This systemic parasite infection can cause you to become anxious or restless.
Weight loss
Some parasites can interfere with your ability to absorb the nutrients from ingested foods. In some instances, a parasite may induce nausea, which may decrease your desire to consume food. These types of parasites may lead you to lose a significant amount of weight over a very short period of time.
