Many children and adults infected with Giardia lamblia have no symptoms of giardiasis, even if they came into contact with the parasite which is also present in their faeces. These individuals can transmit the disease to others.
When giardiasis symptoms are present, they are most common represented by:
- Diarrhea that usually lasts 7-10 days. It may take longer but also can improve even more quickly in 2-4 days. First is present watery diarrhea, followed by steatorrhea (fat presents), foul-smelling stools that may float. This is a sign that fat is not digested properly and are transferred from the body in the stool
- Abdominal cramps and tenderness
- Nausea and loss of appetite
- Flatulence (gas) or bloating
In many cases, infected people do not seek treatment for these symptoms and giardiasis symptoms often improve by themselves. But if giardiasis is not treated after the first symptoms, the disease can last a long time and can become chronic. People with chronic giardiasis present diarrheal attacks which appear and disappear accompanied by the symptoms described above. These episodes alternate with periods of constipation or normal bowel movements and last only a few days when they occur. For these reasons, they do not seek medical treatment. Symptoms of chronic giardiasis include:
- Loose stools, fat, unbound (not always liquid or aqueous), sometimes foul-smelling stools and sparkling and often in small amounts
- Abdominal discomfort or gastric irritation are common after meals
- Abdominal cramps, bloating or pain
- Fetid halitosis (bad breath odor) persistent smell of sulfur sometimes
- Occasional headaches
- Weight loss
- General malaise, asthenia, fatigue, general feeling of discomfort.
Giardiasis Symptoms In Children
Children with giardiasis may show no symptoms other than impaired growth and weight loss. If gardiasis symptoms are present:
- Foamy diarrhea, yellow, foul-smelling
- Weight loss or loss of appetite
- Abdominal pain, nausea or vomiting
- Nutritional deficiencies caused by failure of absorption of nutrients.
Breastfeeding protects infants from giardiasis. Breast milk contains nutrients that kill parasites. These are common symptoms of giardiasis and other intestinal infections. Duration of symptoms and parasite identification test may be the only ones that sustain the differential diagnosis of these diseases.
Symptoms of giardiasis usually appear 7-10 days after infection, although it can sometimes take 35 days or more. Once emerged, the symptoms last at least 7 weeks:
- In children or adults with no other diseases, the symptoms may disappear without treatment
- Long-term diarrhea can cause weight loss, dehydration or nutritional problems because foods are not absorbed properly in the body.
Sometimes these problems get better without treatment. If this happens, can be treated properly.
Many people who are infected with Giardia intestinalis have no symptoms, infection although they can infect other people even if no symptoms of gardiasis are present due to the fact that the parasite is still present in the stool (faeces). Among people who have symptoms of giardia, 20% to 40% develop a temporary intolerance to milk or other milk-based products (lactase deficiency or lactose intolerance). This problem may take up to one month after the end of treatment for giardia. This means that treatment was not effective or reinfection occurred.
Newborns and infants with giardiasis may refuse food and may stop growing until the disease is cured. Normal growth and body development do not occur immediately but may resume in weeks or months. Studies have shown that it is possible that a person who infected with giardiasis to develop short-term immunity to the parasite.