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Brainerd Diarrhea - Types, Causes, Prevention and Treatment

Published on Sep 12, 2022 and last reviewed on Mar 17, 2023   -  4 min read


Brainerd diarrhea is defined as the acute onset of watery diarrhea lasting more than four weeks.


Brainerd diarrhea is a sudden onset, watery explosive diarrhea that lasts for months. The cause of Brainerd diarrhea is unknown. Brainerd diarrhea is named after Brainerd, Minnesota, the town where the first outbreak of the disease occurred in 1983. The condition can occur in outbreaks or as sporadic cases. The disease has been associated with raw milk and contaminated water consumption. Brainerd diarrhea cannot be passed from one person to another.

What Are the Clinical Types of Diarrhea?

There are three clinical types of diarrhea:

  • Acute Watery Diarrhea - Itis the most common and lasts several hours or days. Acute bloody diarrhea. This condition is also known as dysentery.

  • Persistent Diarrhea - It lasts 14 days or longer.

  • Chronic Diarrhea - It lasts longer than four weeks.

What Is the History of Brainerd Diarrhea?

Since 1983, eight outbreaks of Brainerd diarrhea have been reported, seven of which have been in the United States. Although the causative factor remains unidentified, the epidemiologic and clinical findings are mostly similar. All Brainerd diarrhea outbreaks occurred in rural settings and primarily affected elderly persons. Most of the patients had symptoms that lasted greater than one year, and no one had significant improvement with antimicrobial therapy. Biopsies of colonic tissue from many patients showed intraepithelial lymphocytosis, a finding typical of Brainerd diarrhea.

What Causes Brainerd Diarrhea?

The cause of Brainerd diarrhea is not known despite many clinical and laboratory investigations.

No infectious agent or toxins are found to cause Brainerd diarrhea. However, inadequately chlorinated or unboiled contaminated water is identified as a source of Brainerd diarrhea in some cases.

What Are the Symptoms of Brainerd Diarrhea?

The symptoms of Brainerd diarrhea include:

  • There is watery, non-bloody diarrhea (ten to 20 times per day) with urgency and fecal incontinence.

  • Gas.

  • Mild abdominal cramping.

  • Minimal weight loss.

  • Nausea, vomiting, and fever are rare.

What Is the Diagnosis of Brainerd Diarrhea?

Since the cause is unknown, no laboratory test can confirm the diagnosis. Brainerd diarrhea should be suspected in any person who has a history of acute onset watery diarrhea lasting more than four weeks. The stool culture for examining parasites also tests negative. Brainerd diarrhea does not show any specific laboratory findings. Colonic biopsy specimens examined under the microscope showed mild inflammation and increased lymphocyte count. The small intestine and stomach appeared normal.

How Can Brainerd Diarrhea Be Treated?

There is no specific treatment for Brainerd diarrhea. Brainerd diarrhea usually resolves on its own without any treatment. Symptoms may come and go and last up to a year or more. A wide range of antimicrobials has been tried and showed no success rate. The antimicrobials include Ampicillin, Ciprofloxacin, Doxycycline, Metronidazole, and Paromomycin. Steroids and anti-inflammatory agents also showed no response. Opioid antimotility drugs such as Loperamide and Diphenoxylate showed some relief of symptoms in about 50 % of patients.

What Are the Other Causes of Watery Diarrhea?

Many diseases and conditions can cause diarrhea, including:

  • Bacterial and Parasitic Infections: Exposure to escherichia coli or parasites through contaminated food or water can cause diarrhea. Traveler's diarrhea is caused by bacteria and parasites when traveling in developing countries. Clostridium difficile is another bacteria that causes diarrhea and occurs after using certain antibiotics or a hospital stay.

  • Viral Infections: Viral infection causing diarrhea include enteric adenovirus, astrovirus, norovirus, cytomegalovirus, and viral hepatitis. Rotavirus can cause diarrhea in children. The virus that causes corona disease is also associated with nausea, vomiting, and diarrhea.

  • Medications: Many medications can cause diarrhea. Some antibiotics kill the good bacteria and disturb the intestine's normal bacterial flora, resulting in diarrhea or other infections. Anti-cancer drugs and antacids containing magnesium can cause diarrhea.

  • Lactose Intolerance: Lactose is a sugar found in milk and other dairy products. People who find it difficult to digest lactose will have diarrhea after eating dairy products.

  • Fructose: Fructose is a sugar found in fruits and honey. Fructose intolerance can also lead to diarrhea.

  • Artificial Sweeteners: Sorbitol and mannitol are artificial sugars found in chewing gum and other sugar-free products. They can cause diarrhea.

  • Surgery: Gallbladder removal and intestine surgery can cause diarrhea.

  • Digestive Disorders: Crohn's disease, ulcerative colitis, celiac disease, and small intestinal bacterial overgrowth can cause diarrhea.

How Can We Prevent Brainerd Diarrhea?

Avoid drinking unpasteurized raw milk and unboiled unchlorinated water will help prevent Brainerd diarrhea. Once the exact cause of Brainerd diarrhea is identified, other preventive measures can be taken.

How Can We Prevent Other Types of Watery Stools?

Washing hands properly can prevent the spread of infectious diarrhea. Proper washing should follow:

  • Wash the hands before and after preparing food. Wash the hands after using the toilet, sneezing, coughing, blowing the nose, or changing diapers.

  • Wash the hands with soap and water for at least 20 seconds.

  • Use an alcohol-based hand sanitizer that contains at least 60 % alcohol.

  • Children should be vaccinated against rotavirus, the most common cause of viral diarrhea.

  • Travelers' diarrhea occurs in people who travel to countries with poor sanitation. To reduce the risk of traveler's diarrhea:

  • Eat hot, well-cooked foods.

  • Avoid peeled fruits and vegetables.

  • Avoid undercooked meat and dairy foods.

  • Drink bottled water.

  • Avoid tap water and ice cubes.

What Are the Lifestyle Changes and Home Remedies for Diarrhea?

Some home remedies for diarrhea include:

  • Drinking plenty of liquids and juices can reduce the symptoms.

  • Avoid caffeine and alcohol.

  • Avoid certain foods such as dairy products, fatty foods, and high fiber foods.

  • Over-the-counter anti-diarrheal medications such as Loperamide and Bismuth salicylate help reduce the frequency of watery stools.

  • Probiotics available in capsule or liquid form can be taken to restore the healthy bacteria in the intestinal tract.


Brainerd diarrhea is a self-limiting condition. Symptoms present for up to a year or more. Long-term follow-up studies showed complete resolution of the patients in three years. There are no chances of relapse once the disease is completely resolved.

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Last reviewed at:
17 Mar 2023  -  4 min read




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