Amoebiasis: Symptoms, Causes, and Treatment Options

What Is Amoebiasis?

Amoebiasis is an infection of the intestines caused by the protozoan parasite Entamoeba histolytica. The parasite typically colonises the large intestine. While many infections remain asymptomatic, invasive amoebiasis can cause colitis and systemic disease, ranging from mild diarrhoea to severe dysentery. In some cases, the parasite can also invade the intestinal wall and spread to other organs, such as the liver, leading to more serious complications.

While many people infected with E. histolytica remain asymptomatic, others may experience acute or chronic symptoms.

Who Does Amoebiasis Affect?

Amoebiasis can affect people of all ages and backgrounds, but certain populations are at higher risk of infection. These include:

• Residents of or travelers to developing countries with poor sanitation
• Individuals living in institutions such as mental health facilities or nursing homes
• People who engage in oral-anal sexual practices
• Immunocompromised individuals, such as those with HIV/AIDS or undergoing chemotherapy
• Young children and the elderly, who may have weaker immune systems

However, with proper hygiene practices and prompt medical care, the risk of severe complications can be significantly reduced.

How Do You Get Amoebiasis?

Amoebiasis is typically contracted through the following routes:

• Ingesting food or water contaminated with E. histolytica cysts
• Coming into contact with surfaces or objects contaminated with infected fecal matter
• Engaging in sexual practices that involve oral-anal contact
• Inadequate hand hygiene after using the restroom or changing diapers

The parasite's cysts can survive outside the body for weeks to months, making it easy for the infection to spread in areas with poor sanitation.

How Common Is Amoebiasis?

Amoebiasis is a major health concern in many developing countries, especially in tropical regions with substandard sanitation. The WHO estimates that Entamoeba histolytica infects about 50 million people worldwide each year. In India, studies suggest a prevalence rate of 3-23% in the asymptomatic population and 0.64-11% in symptomatic patients.

How Will Amoebiasis Affect Me?

The impact of amoebiasis can range from mild to severe. Some people experience no symptoms at all, while others develop amoebic dysentery with abdominal cramps, diarrhoea, and bloody stools. If the parasite spreads beyond the gut, it can cause liver abscesses, leading to fever, nausea, and right upper abdominal pain. In rare cases, Entamoeba histolytica can even reach the lungs or brain, causing serious complications.

Symptoms of Amoebiasis

The symptoms of amoebiasis can range from mild to severe, depending on the extent of the infection. Some common symptoms include:

• Diarrhoea, which may be watery or bloody (amoebic dysentery)
• Abdominal pain and tenderness
• Nausea and vomiting
• Fever and chills
• Fatigue and weakness
• Unintended weight loss

In some cases, amoebiasis may cause more severe symptoms, such as:

• Severe abdominal pain
• High fever
• Profuse bloody diarrhoea
• Dehydration
• Liver abscess (characterised by right upper quadrant pain, fever, and jaundice)

Causes of Amoebiasis

Amoebiasis is caused by the protozoan parasite Entamoeba histolytica.

Common causes of amoebiasis include:

• Consuming food or water contaminated with E. histolytica cysts
• Poor hand hygiene, especially after using the restroom or changing diapers
• Engaging in sexual practices that involve oral-anal contact
• Travelling to or living in areas with inadequate sanitation and limited access to clean water.

The cysts can survive for weeks to months outside the body, making it easy for the infection to spread in areas with poor sanitation.

Complications of Amoebiasis

Potential complications of amoebiasis include:

• Amoebic dysentery: A severe form of intestinal amoebiasis characterised by bloody diarrhoea, abdominal pain, and fever.
• Liver abscess: The most common extraintestinal complication, occurring when the parasite spreads to the liver and forms a pus-filled cavity.
• Peritonitis: Inflammation of the abdominal lining, which can occur if an amoebic liver abscess ruptures.
• Spread to other organs: In rare cases, the parasite can spread to the lungs, brain, or other organs, causing serious and potentially life-threatening infections.
• Malnutrition and dehydration: Chronic diarrhoea and intestinal inflammation can lead to malnutrition and dehydration, especially in young children and elderly individuals.

Is Amoebiasis Contagious?

Yes, amoebiasis is contagious. The cysts shed in an infected person's stool can spread the parasite to others through contaminated food, water, or surfaces. Household members and caregivers of people with amoebiasis are at higher risk, as are people in institutions with poor hygiene. Travellers to high-risk areas can also contract the infection and spread it upon return.

How Is Amoebiasis Diagnosed?

Diagnosing amoebiasis involves a combination of clinical evaluation and laboratory tests. A doctor will typically start by reviewing the patient's symptoms, medical history, and potential risk factors, such as recent travel to endemic areas or exposure to contaminated food or water.

Exams and Tests

Laboratory tests used to diagnose amoebiasis may include:

• Stool examination: Microscopic examination of stool samples to identify E. histolytica cysts or trophozoites.
• Antigen detection tests: Enzyme-linked immunosorbent assay (ELISA) or rapid antigen tests to detect E. histolytica antigens in stool samples.
• Molecular tests: Polymerase chain reaction (PCR) tests to detect E. histolytica DNA in stool or other clinical samples.
• Serological tests: Blood tests to detect antibodies against E. histolytica, which can indicate current or past infection.

In cases of suspected extraintestinal amoebiasis, such as liver abscesses, additional diagnostic tests may be necessary, such as:

• Imaging studies: Ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI) to visualise liver lesions or other affected organs.
• Aspiration of liver abscess: Ultrasound-guided aspiration of liver abscess contents for microscopic examination and culture.

How Is Amoebiasis Cured?

Amoebiasis treatment typically involves a combination of antibiotics:

1. Tissue amebicides: Medications like metronidazole or tinidazole to eliminate amoebae that have invaded the intestinal lining.
2. Luminal amebicides: Medications such as paromomycin or iodoquinol to clear remaining parasites from the gut.

For severe infections like amoebic liver abscesses, needle aspiration or drainage may be necessary along with antibiotics. Entamoeba histolytica treatment usually lasts 5-10 days, but longer courses may be needed for complicated cases. Completing the full course is crucial to prevent recurrence.

What Other Conditions Put Me at Higher Risk for Amoebiasis?

Several factors can increase a person's risk of contracting amoebiasis, including:

• Living in or traveling to areas with poor sanitation and limited access to clean water, such as developing countries in tropical and subtropical regions
• Consuming contaminated food or water
• Engaging in sexual practices that involve oral-anal contact
• Having a weakened immune system due to conditions like HIV/AIDS, cancer, or diabetes
• Taking immunosuppressive medications, such as corticosteroids or chemotherapy medicines
• Engaging in poor hygiene practices, such as not washing hands thoroughly after using the restroom or before preparing food.

At Metropolis Healthcare, we understand the physical and emotional toll digestive issues like amoebiasis can take. That's why we're committed to providing reliable, high-quality diagnostic testing to help you get answers and appropriate treatment fast. Our team of expert phlebotomists can collect your samples in the comfort of your home, and our state-of-the-art labs will process them with utmost precision. With Metropolis, taking charge of your gut health is convenient and hassle-free.

FAQs

How can I reduce my risk of amoebiasis?

Practise good hygiene by washing hands with soap and water, especially before preparing or eating food. When travelling in high-risk areas, drink only bottled water, avoid ice cubes, and eat cooked foods.

Is amoebiasis life-threatening?

In most cases, amoebiasis causes mild symptoms that resolve with proper treatment. However, if left untreated, the infection can lead to severe complications like perforated bowel or liver abscess, which can be life-threatening. Prompt diagnosis and amoebiasis treatment are essential.

What can I expect if I have amoebiasis?

With appropriate antibiotics, most people with amoebiasis start feeling better within a few days. Symptoms like diarrhoea and abdominal pain should gradually resolve over 1-2 weeks. Be sure to complete the full course of medication, stay hydrated, and get plenty of rest.

How is amoebiasis transmitted?

Amoebiasis spreads when someone ingests food or water contaminated with Entamoeba histolytica cysts shed in the faeces of an infected person. This can happen with poor sanitation, inadequate hand washing, or through oral-anal sexual contact.

How many days does amoebiasis last?

The duration of amoebiasis symptoms varies. Without treatment, diarrhoea can persist for weeks to months or come and go in cycles. With proper amoebiasis treatment, most people feel better within a few days, with symptoms resolving over 1-2 weeks.

Can amoebiasis be cured permanently?

Yes, amoebiasis can be cured completely with the right medications that target the parasite in both the intestinal wall and the gut lumen. However, reinfection is possible if one is exposed to contaminated food or water again.