How Common Is Balamuthia Mandrillaris?

Medically Reviewed on 11/29/2022
Balamuthia Mandrillaris
Balamuthia mandrillaris infection may infect anyone and happen at any time of year.

Balamuthia mandrillaris is a newly identified amoeba that causes brain and skin infections. Infection due to Balamuthia mandrillaris is extremely rare but fatal.

Balamuthia mandrillaris can cause Balamuthia amoebic encephalitis (BAE), which is fatal in most cases.

  • There have been about 200 incidences of Balamuthia mandrillaris infection globally, making it the least-known, brain-eating amoeba in the medical community. It is slow-acting and takes weeks or months to become fatal.
  • There have been only 11 verified survivors. This figure includes over 100 confirmed cases in the United States. Because Balamuthia illness is so unusual, there were probably more instances that were misdiagnosed.

The available data for BAE suggest that this condition is difficult to diagnose because information on predisposing conditions is insufficient. The number of documented BAE cases is rising globally, which is a major concern because little is known about the pathogen. 

There are no standardized diagnostic methods, and most treatments are almost entirely empirical.

What are the signs and symptoms of Balamuthia mandrillaris infection?

Balamuthia is present in soil and possibly water. The contamination happens through the respiratory route or skin lesions (breaks in the skin). The disease can begin with a wound on the face, trunk, or limbs and then progress to the brain, where it causes a condition called granulomatous amebic encephalitis (GAE).

Common signs and symptoms of Balamuthia mandrillaris infection may include:

  • Sore or a rash on the nose
  • Headache
  • Lethargy
  • Low-grade fever
  • Characteristics skin lesions
    • Similar to those caused by MRSA and do not respond to antibiotics
    • The lesion is generally localized and heals slowly or does not heal at all
  • Balamuthia lesions on the face often cause swelling
  • Stiff neck
  • Nausea
  • Vomiting (sensitive to heat and light)
  • Acute confused state
  • Change in personality or mental health changes
  • Aphasia (impairment of language) or problems with speech, walking, and coordination
  • Partial paralysis
  • Seizures
  • Blurry vision
  • Weight loss

Balamuthia can infect the skin, sinuses, brain, and other organs. It might start as a non-healing skin lesion and proceed to GAE. Though the infection develops gradually, the condition worsens over weeks to months.

Most of the time, the diagnosis is obtained after death by autopsy.

Who is at risk of getting Balamuthia mandrillaris infection?

Balamuthia mandrillaris infection may infect anyone and happen at any time of year. It does not, however, spread through human-to-human transmission.

A person can get infected when:

  • Amoeba-containing soil comes into touch with cut or wounded skin
  • Dust containing amoeba is inhaled into the lungs
  • Using the contaminated water

When the amoeba enters the body, they flow in the bloodstream until they reach the brain and cause granulomatous amebic encephalitis (GAE).

Risk factors

  • Balamuthia infection is more common in North and South America. B. mandrillaris amoebic encephalitis (BAE) is more frequently found in warmer regions, such as Southern California and South America.
  • Typically affects children and, in the United States, men of Hispanic descent.
  • Transmission through organ transplantation has been reported with an incubation period of 17 to 24 days.
  • Swimming in lakes, ponds, or pools could be a risk factor. Swimming in warm freshwater lakes and rivers was the most common cause in a few cases, but in rare instances, infections occur after tap water gets into the nose.


Bowel regularity means a bowel movement every day. See Answer

How is Balamuthia mandrillaris infection treated?

The infection should be treated quickly and aggressively because most individuals with the cutaneous infection die because of the development of granulomatous amoebic encephalitis (GAE). In most cases, the key was to initiate antimicrobial treatment early. Balamuthia infection has had successful treatments.

A cocktail of antibiotics and antifungal drugs is usually recommended. Multidrug combinations include:

  • Pentamidine (intravenous)
  • Sulfadiazine (oral)
  • Flucytosine (oral)
  • Fluconazole (intravenous or oral)
  • Itraconazole (oral)
  • Azithromycin (intravenous or oral) or clarithromycin (oral)
  • Miltefosine (oral)
  • Nitroxoline worked well in vitro and might be a possible treatment for this infection
  • These drugs with or without surgical resection of the central nervous system lesions

However, these drugs reveal harmful systemic side effects, including nephrotoxicity.

What is the prognosis Balamuthia mandrillaris infection?

Typically, the outcome is fatal. Most Balamuthia cases are discovered shortly before or after death.

Current treatment options are based on lab results and a few surviving cases. People who survived were 2 to 80 years old, implying that age may not be a factor in prognosis.

Early treatment with antifungal, antihelmintic, and antiprotozoal medications (sometimes in combination) may increase the likelihood of survival. Because Balamuthia infection is extremely rare, more research is needed to develop a concrete treatment method.

There is an urgent need for improved antimicrobial chemotherapy, alternative therapeutic intervention strategies, and education on such infections.

Medically Reviewed on 11/29/2022
Image Source: CDC image

Parasites - Balamuthia mandrillaris - Granulomatous Amebic Encephalitis (GAE).

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