Infectious Diarrhea: 7 Causes, Symptoms & What to Do

Infectious diarrhea is a type of diarrhea caused by an viral, bacterial or parasitic infection. Normally, this type of diarrhea causes fever in addition to other symptoms, like vomiting and bloody stools. 

Ideally, the cause the diarrhea should be identified, as this will help to optimize treatment and prevent complications. Therefore, if you suspect your diarrhea is related to an infection, you should see your doctor for assessment. 

You are advised to avoid the use of anti-diarrhea medications, as this will cause the infectious agent to remain in the intestines and cause further complications. You should drink plenty of fluids to prevent dehydration and maintain a healthy, light diet that is aimed at eliminating the microorganism causing the infection. 

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What causes infectious diarrhea

The main causes of infectious diarrhea are:

1. Virus

A viral infection is one of the many causes of infectious diarrhea, especially in children between the ages of 6 months and 2 years old. It is normally related to a rotavirus, and can be easily transmitted between children through the fecal-oral route. 

Symptoms: This diarrhea is very intense and has a strong odor. Other symptoms like fever and vomiting can also occur. 

What to do: If you suspect a rotavirus infection, you should take the child to a doctor for assessment and treatment, which will depend on the presenting symptoms. You should offer the child water and natural fruit juices to prevent dehydration and serve meals that are light to speed-up recovery. 

2. Salmonella sp.

A salmonella infection occurs through the ingestion of foods contaminated by this bacteria. The most commonly affected foods are eggs and raw chicken meat. 

Symptoms: Intense diarrhea, vomiting and high fever. Symptoms of a salmonella infection can emerge up to 10 days after initial contact with the bacteria, depending on how concentrated the bacteria levels were in the food. Learn more about salmonella infections and what can cause them. 

What to do: It is important to drink plenty of fluids and maintain a light diet. You should also see your doctor to diagnose a salmonella infection, so that treatment with antibiotics can be initiated if necessary. 

3. Shigella sp.

Infectious diarrhea caused by a Shigella sp. bacteria can also occur if food or water contaminated with this bacteria are ingested. Read more about food poisoning and how it is transmitted.

Symptoms: You may experience a stomach ache, nausea, vomiting, and a headache in addition to diarrhea. Shigella infection symptoms disappear after 5 to 7 days, however if they persist or worsen, you should see a doctor for diagnosis and treatment. 

What to do: To treat a Shigella infection, the doctor will usually advise, rest, fluids and an antibiotics like azithromycin to quickly eliminate the bacteria from the body. Antibiotics are only recommended when symptoms do not improve and diarrhea lasts for over 7 days. 

4. Escherichia coli

Escherichia coli, or simply E. coli, is a bacteria that is naturally present in the intestines. However it can also be related to cases of diarrhea, because there are types of E. coli found in food that can produce diarrhea-inducing toxins. 

Symptoms: Generally, abdominal pain will emerge, as well as a low fever and blood in the stool. 

What to do: E. coli infections should be identified through stool testing, which will be able to capture which antibiotic is most reactive for treatment of this bacteria. In addition, rest, fluids and light, balanced meals are recommended when treating this infection. Understand which medications and home remedies to use to treat a fever at home.  

5. Giardia lamblia

Giardia lamblia is a parasite that is responsible for diarrhea in children. It occurs due to the ingestion of eggs from this parasite, which are found in water and contaminated foods. This infection is commonly referred to as giardiasis. 

Symptoms: Giardiasis can present with diarrhea, nausea, yellow or green stools and abdominal pain. Learn about other causes of yellow poop

What to do: If you suspect a giardiasis infection in your child, the child should be assessed by a pediatrician. The doctor may order stool testing to identify the presence of the parasite eggs in the poop. Once diagnosis is confirmed, the doctor may prescribe antiparasitics like metronidazole or secnidazole, as advise rest and fluids throughout recovery. See what else can cause green stools and how to treat it. 

6. Roundworms

Roundworms, or Ascaris lumbricoides, are a parasite that can develop in the intestines. They are transmitted through the ingestion of contaminated food and water. For this reason, food should always be properly handled and well-cooked.

Symptoms: They can cause diarrhea, abdominal discomfort and vomiting. 

What to do: Treatment for roundworms involves the use of antiparasitics like albendazole and ivermectin, which aim to eliminate these parasites. These medications should be taken as prescribed by the doctor. If you have abdominal pain, you should also avoid eating foods that cause excess gas.

7. Amebiasis

Entamoeba histolytica is a parasite that causes amebiasis, which is an infectious disease that commonly affects children who live in tropical climates or in conditions with poor sanitation. 

Symptoms: It can cause intense diarrhea, fever, stools with blood, nausea and fatigue. 

What to do: It is important that that  Entamoeba histolytica parasite is identified so that it can be treated quickly without any further complications. Therefore, if you notice any symptoms of an infectious diarrhea, the child should undergo stool testing to confirm a diagnosis and start treatment. Treatment usually involves the use of metronidazole for 10 days as prescribed by the doctor. Read more about how nausea can be treated.