Microbiologist seeks treatment for lethal parasitic brain disease

An intestinal parasite that has long existed in areas of Mexico and nations to the south is now making its way across the border with more frequency.

With an infection cycle that includes infiltration of the brain and nervous system, the resulting disease, neurocysticercosis, has caught the attention of researcher Judy Teale, Ph.D., a professor in the Department of Microbiology at the Health Science Center.

Dr. Teale is working to determine the effects of current treatments for the disease and the role of certain cells in immune response, with the goal of developing better medicines.

Neurocysticercosis begins with the ingestion of parasitic eggs that eventually result in the infection of the brain and central nervous system by larvae. Patients suffering from neurocysticercosis vary in terms of symptoms. Some are asymptomatic and the disease is not even found until the patients have died. Others exhibit a variety of maladies, including headaches, nausea and seizures.

Depending upon the length of infection and the location of the parasitic larvae, patients also may suffer more life-threatening conditions, including increased pressure on the brain.

The initial parasitic infection is largely the result of poor hygiene during food preparation and inadequate sanitary conditions. The disease is normally seen in Third World countries where standards in food preparation and sanitation are lower. But as people migrate from Mexico into the United States, local hospitals are seeing more and more cases of neurocysticercosis. University Hospital now treats several cases a month.

“It is the most common parasitic disease of the central nervous system worldwide,” Dr. Teale said. “It is a really serious problem.”

The larvae of the parasitic brain disease develops and lives inside this fluid-filled bladder sac. The smaller sac (left) represents one of normal size while the larger sac, which is more than 9 cm in length, if found in some patients. The large sac weaves in and out of spaces within the brain and can cause severe symptoms.

Little research has been conducted on this life-threatening disease. Current treatments, including anti-helminthic drugs (which have the power to destroy or expel intestinal worms), have been known to cause adverse side effects and additional problems for patients instead of alleviating illness altogether.

Dr. Teale has been working to define the brain’s immune response following treatment with the anti-helminthic drugs, including what cells are involved and what those cells secrete. She has determined that one particular type of cell, the gamma delta T-cell, is involved in controlling the infection in animal models, but research will continue to determine exactly what this cell does.

“It is the kind of cell that infiltrates—a massive infiltration—and it seems to be involved in controlling the infection in animals,” Dr. Teale said. “So we are doing studies to figure out the exact role of these gamma delta T-cells.”

Dr. Teale said prevention is key in stopping the spread of neurocysticercosis. The old adage warning tourists to steer clear of the drinking water in many foreign countries may not be the only caution to remember when traveling. Fruits and vegetables, which become contaminated with parasite eggs during the fertilization process, also should be under scrutiny and should be washed thoroughly. Preferably, salads should be avoided and fruits should be peeled prior to eating. Strawberries are a particular risk.

“It is becoming more and more of a problem in the U.S.,” Dr. Teale said. “In some areas of the United States, physicians are not used to seeing it, and it will take a lot longer to diagnose and treat.”