What is a parasite?
Parasites are defined as organisms that live on or in another organism – known as the host – and survive by taking nutrients from the host. Humans become hosts by accidentally ingesting parasites, or eggs that later hatch into parasites. Parasites can survive for weeks or months in the human body, most commonly in the intestinal tract, before they are detected.
Some common symptoms of parasitic infection include the following:
- Nausea and vomiting
- Abdominal craps
- Loss of appetite
- Headaches and fever
How do we become infected?
Parasites can enter our bodies in a number of ways, including the following:
- Swallowing contaminated water: This is the most common way in which we become infected. Many parasites can be found in lakes, rivers, cisterns, municipal water supplies and wells. Water becomes infected as a result of agricultural runoff, animal feces and the discharge of wastewater. Swimming pools can be contaminated by children having “accidents” and by people with gastrointestinal illnesses.
- Eating contaminated food: We can become infected by eating raw produce that has been washed with contaminated water, or that has been handled by an individual who is infected. However, this is a less common means of infection since cooking kills many parasites.
- Person-to-person contact: People who regularly change diapers are at higher risk of parasitic infection. Parasites can also be transmitted through anal sex.
Are some people at higher risk of parasitic infection?
The risk of infection varies from one parasite to the next, but some common risk factors include the following:
- Age: Some parasites are more common in children, especially those who wear diapers, or who attend daycare centres.
- Occupation: Parents of children in diapers, child care workers, personal support workers and those who work with animals are more susceptible.
- Access to a clean water supply: Parasites are spread far more easily in places that lack proper sanitation. Tourists who travel to such places frequently become infected.
- Sexual practices: Unprotected anal sex raises the risk of parasitic infection.
What complications can arise?
Parasites are generally not life-threatening for otherwise healthy individuals. However, serious complications can arise in babies and children, seniors and people with other health problems. Complications include the following:
- Dehydration: Many parasites cause diarrhea and vomiting, resulting in reduced ability to take in enough fluids.
- Failure to thrive: Children can suffer from impaired physical and mental growth.
- Lactose intolerance: Some people develop an inability to digest milk sugar which can persist for months or years after the infection has passed.
- Inflammation: Internal organs such as the liver, bile duct and pancreas can become inflamed.