G. lamblia are found in human faeces. These parasite also thrive in contaminated food, water and soil and also they can survive outside the host for longer period of time. Accidentally consuming these parasite might leads to an infection.
The most common way to get giardiasis is to drink water that contain G. lamblia. Contaminated water can be in swimming pools, spas, and bodies of water, such as lakes. Sources of contamination include animal feces, diapers, and agricultural runoff.
Contracting giardiasis from food is less common because heat kills the parasites. Poor hygiene when handling food or eating produce rinsed in contaminated water can allow the parasite to spread.
Giardiasis also spreads through personal contact. For example, unprotected anal sex can pass the infection from one person to another.
Changing a child’s diaper or picking up the parasite while working in a day care center are also common ways to become infected. Children are at high risk for giardiasis because they’re likely to encounter feces when wearing diapers or potty training.
The following includes the risk factor:
The infection is more common among children than in adults. Children are more likely to get the disease as they come in contact with the faeces especially if they wear diapers, toilet training or spend time in a child care center. People who is with small children are also at higher risk of developing the disease.
People without access to safe drinking water:
Giardia infection is present in the areas where adequate sanitation is not present. The person is at higher risk when he/she travels to distant places. The risk is greatest in rural od wilderness areas.
People having anal sex:
People who have anal sex or oral-anal sex without using a condom or other protection are at increased risk of giardia infection, as well as sexually transmitted infections.
Giardia infection is almost never fatal in industrialized countries. But it can cause lingering symptoms and serious complications, especially in infants and children. The most common complications include:
- Dehydration. Often a result of severe diarrhea, dehydration occurs when the body doesn't have enough water to carry out its normal functions.
- Failure to thrive. Chronic diarrhea from giardia infection can lead to malnutrition and harm children's physical and mental development.
- Lactose intolerance. Many people with giardia infection develop lactose intolerance — the inability to properly digest milk sugar. The problem may persist long after the infection has cleared.