Certain common human stomach parasites often affect the entire digestive system, entering the body through the mouth and traveling to the intestines, where they will ultimately reside and reproduce. Poor hygiene is the common denominator in contracting stomach parasites. Taking proper hygienic precautions, like washing your hands and filtering questionable water sources, can help prevent parasitic infestation.
Entamoeba Histolytica
Humans are the primary host of the Entamoeba histolytica parasite, the most common pathogenic human parasite. Entamoeba histolytica often strike through from contaminated food or water. Untreated sewage is a common source of water contamination. Symptoms of infestation include dysentery, bloody stool, and abdominal pain. It is possible for this parasite to eat its way through the intestinal walls and infest other vital organs and viscera, sometimes resulting in death.
Balantidium Coli
The primary host of the Balantidium coli is the pig, but the parasite can also infect humans. Eating Balantidium eggs or drinking a contaminated item are common ways to contract this parasite, which primarily affects the intestines, and can lead to a condition known as balantidiasis. Signs of balantidiasis are diarrhea, dysentery, abdominal pain, nausea, and vomiting. The presence of this parasite can be confirmed through examination of stool samples.
Giardia Lamblia
Giardia lamblia may be found in contaminated soil, water, or food. Contamination usually results from drinking water polluted with fecal matter. Infestation can result in diarrhea and abdominal pain, and can also cause a chronic fatigue syndrome which complicates diagnosis.
Ascaris Lumbricoides
Ascaris lumbricoides is a common intestinal roundworm, acquired by consuming food or drink tainted with the parasite's eggs. Infestation is often the result of poor hygiene, substandard sanitation, or the use of human feces as fertilizer. The life cycle of the roundworm begins in the intestines, where the eggs hatch to release roundworm larvae. The larvae then travel to the lungs via the bloodstream. From the lungs, the roundworms enter the airways, and are swallowed once again, returning to the intestines, where they will mature and pass on their eggs via the host's feces. Symptoms of infestation are rare, though various respiratory and intestinal conditions may result from hosting Ascaris lumbricoides.
