Balamuthia Mandrillaris Balamuthia Mandrillaris
Centers for Disease Control and Prevention

Balamuthia mandrillaris ameba infection

Balamuthia mandrillaris is a free-living ameba (a single-celled organism) found in soil and dust. Exposure to Balamuthia is likely to be common because of how widespread it is in the environment. However, very few cases of disease in humans have been found worldwide since Balamuthia was discovered.

Photo courtesy of DPDx. What is Balamuthia mandrillaris?

Balamuthia is a free-living ameba found in the environment. It was first identified in 1986 in a specimen from the brain of a baboon that died in the San Diego Wild Animal Park. Since then, approximately 200 cases of Balamuthia disease have been reported worldwide; approximately 70 of those cases have been reported in the United States. Little is known at this time about how a person becomes infected.

Balamuthia can cause Balamuthia granulomatous amebic encephalitis (GAE), a serious brain infection that is usually fatal. Balamuthia GAE occurs when the Balamuthia amebae infect the body, possibly through skin wounds and cuts, or when dust containing Balamuthia is breathed in through the nose or mouth. The amebae may travel to the brain directly through the sinuses, or through the blood stream. Balamuthia GAE is a very rare but usually fatal disease.

Why is CDC concerned about Balamuthia infection now?

During 2009-2010, CDC identified two clusters of transplant-transmitted Balamuthia GAE. In each cluster, there were four transplant recipients; two transplant recipients became ill while two other recipients from each donor have not shown symptoms. The second cluster of cases is still being investigated. Both clusters are described in the September 17, 2010 issue of the MMWR.

CDC is working with the transplant community to minimize the risk of transmission of potentially fatal infections like Balamuthia through solid organ transplantation, while maximizing the availability of what should be a life-saving procedure.

What are the symptoms of a Balamuthia disease?

The symptoms of Balamuthia disease can begin with a red area of skin on the face, torso, or limbs that gets larger over time. However, some people with Balamuthia never develop skin lesions. Instead, their symptoms begin when the amebas infect the brain, causing Balamuthia GAE. Diagnosis of Balamuthia GAE can be difficult, as it may be easily confused with other neurologic diseases, even non-infectious ones, like stroke.

Some early symptoms might include a combination of the following:

Severe headache Stiff neck, or neck pain with neck movement Sensitivity to light Nausea and vomiting Unusual fatigue Fever Difficulty walking or talking Sudden one-sided weakness Behavioral changes Seizures Unusual skin lesions that persist over months

Symptoms can appear mild at first but can become more severe over weeks to several months. The disease is most often fatal once it spreads to the brain. The best treatment options are still unknown. Only a handful of patients have survived with treatment.

How long after infection do symptoms appear?

It is thought to usually take weeks to months, even over 2 or more years, to develop the first symptoms of Balamuthia GAE after exposure. Patients exposed through solid organ transplantation can develop symptoms of Balamuthia GAE more quickly, within weeks, because of their depressed immune systems.

Who is most likely to get disease from Balamuthia?

Anyone can be exposed to Balamuthia through the environment. This includes people who are healthy or those with weakened immune systems. It is still unknown whether specific factors make people more susceptible to infection and disease from Balamuthia.

What should I do if I think I may have Balamuthia?

Contact your healthcare provider if you think you may have a Balamuthia infection.

How is Balamuthia diagnosed?

Infections with Balamuthia can be diagnosed on biopsies of skin, brain, and other infected tissues through routine pathologic testing. Specialized tests available only through health departments are needed to confirm if the amebas are Balamuthia or another type of ameba. CDC is available to help health departments obtain confirmatory testing for Balamuthia.

What is the treatment for Balamuthia?

Currently, treatment recommendations include the use of a combination of several medicines that have been used with success in a few patients with Balamuthia GAE. To date, treatment plans have been based on lab studies of the ameba and the few cases in which the patients have survived after treatment.

How can I prevent a Balamuthia infection?

Currently, there are no known ways to prevent infection with Balamuthia since it is thought to occur worldwide in soil. It is still unclear how and why some people develop disease after exposure while others do not.

Should I be worried about getting Balamuthia infection from other people?

The only way that Balamuthia has been demonstrated to be transmitted person-to-person has been through solid organ transplantation from an organ donor with Balamuthia GAE. There have been no other reports of Balamuthia infection spreading from one person to another through any other means.