Naegleria Infection (cont.)

After entering the nose, the amoeba travels into the brain along the olfactory nerve and through membranes to enter the brain. Once there, it causes primary amoebic meningoencephalitis (meaning inflammation of the brain and the lining around the brain). In the popular press, Naegleria fowleri is sometimes called the brain-eating amoeba, and meningoencephalitis is sometimes referred to as Naegleriasis.

Symptoms usually appear within five days after exposure but can be delayed up to two weeks. Patients may initially notice changes in smell or taste. Fever, headache, loss of appetite, and nausea follow quickly. The patient becomes confused or semiconscious and finally comatose. Physical examination shows fever and a stiff neck (meningismus).

A spinal tap will be done to examine the spinal fluid. Infection is diagnosed by seeing the amoeba under the microscope. Traditional Gram staining is not used to detect Naegleria because the heat used in the fixation process destroys the organism. Although not specific to Naegleria, the spinal fluid often has a mild elevation in the levels of proteins and a mild decrease in glucose, along with a high white cell count, and is often bloody in the later stages of disease.

Because rapid diagnosis is critical, examination of the spinal fluid is imperative. The organism can also be cultured in the laboratory using on a plate that is coated with bacteria for the amoeba to eat. The culture takes a few days. Newer tests are becoming available that use polymerase chain reaction (PCR) technology to detect amoebic DNA in spinal fluid.

Source: MedicineNet.com
http://www.medicinenet.com/naegleria_infection/article.htm