Giardiasis: everything we know about stomach bug found at UK school

Two children at a Liverpool primary school dealing with a giardiasis infection outbreak have died, health authorities have confirmed.

The children attended Millstead Primary School in Everton, which teaches children aged two to 11 with special educational needs.

The UK Health Security Agency (UKHSA) said a link between their deaths had not been established and they were “unlikely” to be due to a “number of cases” of giardia.

The agency has not confirmed the sex or ages of the children who have died. They were reportedly aged five and six.

So what is giardiasis and its symptoms, how long does it last, is it life-threatening, and how is it treated?

Here is everything you need to know.

What is giardiasis?

Giardiasis is an intestinal infection caused by a microscopic parasite called Giardia lamblia (also called Giardia intestinalis or Giardia duodenalis). This parasite is found worldwide, and giardiasis is one of the most common causes of waterborne disease in humans.

Giardiasis is typically transmitted through ingesting contaminated food or water that contains Giardia cysts. It can also be spread through person-to-person contact in settings where hygiene practices are poor.

Health experts say it affects more than 300 million people a year.

What are the symptoms of giardiasis?

The symptoms of giardiasis can vary from person to person, and some people may be asymptomatic (show no symptoms). However, when symptoms do occur, they typically appear one to three weeks after exposure to the parasite and can include the following:

1. Diarrhoea: Frequent, watery, and sometimes foul-smelling stools.
2. Abdominal cramps and pain: Persistent stomach pain and cramping.
3. Bloating: Feeling of fullness or swelling in the abdomen.
4. Gas: Increased flatulence or burping.
5. Nausea and vomiting: Feeling sick to the stomach, sometimes leading to vomiting.
6. Greasy stools: Stools that may float and have a greasy appearance due to malabsorption of fats.
7. Weight loss: Unintended weight loss due to prolonged diarrhoea and nutrient malabsorption.
8. Fatigue: General feeling of tiredness and lack of energy.
9. Dehydration: Resulting from severe diarrhoea, which can lead to dry mouth, reduced urine output, and dizziness.

Children are more commonly affected by giardiasis than adults. This increased susceptibility is largely due to their tendency to engage in activities that increase the risk of exposure to the parasite, such as playing in contaminated water or putting objects in their mouths.

Additionally, young children are more likely to have close contact with other children, which can facilitate the spread of the infection in settings such as daycare centres and schools.

Giardiasis can cause persistent stomach pain and cramping (Getty Images)

How long does giardiasis normally last?

The duration of a giardiasis infection can vary depending on several factors, including the individual's immune response and whether they receive treatment. Generally, the infection course is as follows:

1. Incubation period: Symptoms typically begin one to three weeks after exposure to the Giardia parasite.

2. Duration of symptoms: Without treatment, symptoms of giardiasis can persist for several weeks to months. In some cases, symptoms may be intermittent, with periods of improvement followed by recurrence.

3. With treatment: When treated with appropriate medications, symptoms usually improve within a few days. The infection is typically cleared within one to two weeks of starting treatment.

4. Chronic cases: In rare cases, giardiasis can become chronic, especially if left untreated. Chronic giardiasis can lead to prolonged symptoms such as malabsorption, weight loss, and fatigue.

Is giardiasis life-threatening?

Giardiasis is rarely fatal, say experts, with approximately 500,000 people dying per year around the world from the condition. Outbreaks can be addressed with the appropriate measures, which the UKHSA has introduced in Millstead Primary School.

However, there are certain populations and situations where giardiasis can pose more serious risks:

1. Dehydration: Severe diarrhoea, especially in infants, young children, the elderly, and individuals with weakened immune systems, can lead to dehydration. In extreme cases, dehydration can become life-threatening if not properly managed.

2. Malnutrition: Prolonged giardiasis can lead to malabsorption of nutrients, causing weight loss and malnutrition. This can be particularly serious in children, as it may affect their growth and development.

3. Immunocompromised individuals: People with weakened immune systems, such as those with HIV/AIDS, undergoing chemotherapy, or taking immunosuppressive drugs, are at a higher risk of severe complications from giardiasis. The infection can be more difficult to treat and may persist longer in these individuals.

4. Chronic infection: In some cases, giardiasis can become chronic, leading to ongoing gastrointestinal issues and malabsorption problems. This can significantly impact quality of life and overall health.

What should I do if I have giardiasis?

The NHS advises that people should seek advice from non-emergency 111 consultants if they have a weakened immune system, diarrhoea lasts longer than a week, or blood is seen in stools.

Cases are usually easily treatable at home, but those struggling may need antibiotics to get better.

Here are the commonly used treatments:

Antibiotics: Several antibiotics are effective in treating giardiasis. The most commonly prescribed include:

• Metronidazole (Flagyl): Typically taken for 5 to 7 days. It is one of the most frequently used treatments for giardiasis.
• Tinidazole (Tindamax): Often given as a single dose, making it convenient for patients.
• Nitazoxanide (Alinia): Usually taken for 3 days, it is another effective treatment option, especially for children.

Supportive care: In addition to antibiotics, supportive care is important to manage symptoms and prevent complications:

• Hydration: It is crucial to drink plenty of fluids to prevent dehydration, especially if experiencing severe diarrhoea. Oral rehydration solutions may be recommended.
• Rest: Adequate rest can help the body recover more quickly.
• Nutrition: Eating a balanced diet and avoiding foods that may aggravate gastrointestinal symptoms, such as dairy products, can help manage symptoms.

Follow-up care: In some cases, symptoms may persist even after treatment, requiring follow-up with a healthcare provider. A stool test may be repeated to ensure the infection has been cleared.

Preventive measures: To avoid reinfection and prevent the spread of giardiasis:

• Practise good hand hygiene by washing hands thoroughly with soap and water, especially after using the toilet and before eating or preparing food.
• Drink only safe, clean water. In areas where water quality is questionable, boil water or use a water filter that can remove Giardia.
• Avoid swallowing water from lakes, rivers, or pools that may be contaminated.
• Wash fruits and vegetables thoroughly before eating.